Analysis of L-glutamic acid fermentation by using a dynamic metabolic simulation model of Escherichia coli.

PubMed

Nishio, Yousuke; Ogishima, Soichi; Ichikawa, Masao; Yamada, Yohei; Usuda, Yoshihiro; Masuda, Tadashi; Tanaka, Hiroshi

2013-09-22

Understanding the process of amino acid fermentation as a comprehensive system is a challenging task. Previously, we developed a literature-based dynamic simulation model, which included transcriptional regulation, transcription, translation, and enzymatic reactions related to glycolysis, the pentose phosphate pathway, the tricarboxylic acid (TCA) cycle, and the anaplerotic pathway of Escherichia coli. During simulation, cell growth was defined such as to reproduce the experimental cell growth profile of fed-batch cultivation in jar fermenters. However, to confirm the biological appropriateness of our model, sensitivity analysis and experimental validation were required. We constructed an L-glutamic acid fermentation simulation model by removing sucAB, a gene encoding α-ketoglutarate dehydrogenase. We then performed systematic sensitivity analysis for L-glutamic acid production; the results of this process corresponded with previous experimental data regarding L-glutamic acid fermentation. Furthermore, it allowed us to predicted the possibility that accumulation of 3-phosphoglycerate in the cell would regulate the carbon flux into the TCA cycle and lead to an increase in the yield of L-glutamic acid via fermentation. We validated this hypothesis through a fermentation experiment involving a model L-glutamic acid-production strain, E. coli MG1655 ΔsucA in which the phosphoglycerate kinase gene had been amplified to cause accumulation of 3-phosphoglycerate. The observed increase in L-glutamic acid production verified the biologically meaningful predictive power of our dynamic metabolic simulation model. In this study, dynamic simulation using a literature-based model was shown to be useful for elucidating the precise mechanisms involved in fermentation processes inside the cell. Further exhaustive sensitivity analysis will facilitate identification of novel factors involved in the metabolic regulation of amino acid fermentation.

Analysis of l-glutamic acid fermentation by using a dynamic metabolic simulation model of Escherichia coli

PubMed Central

2013-01-01

Background Understanding the process of amino acid fermentation as a comprehensive system is a challenging task. Previously, we developed a literature-based dynamic simulation model, which included transcriptional regulation, transcription, translation, and enzymatic reactions related to glycolysis, the pentose phosphate pathway, the tricarboxylic acid (TCA) cycle, and the anaplerotic pathway of Escherichia coli. During simulation, cell growth was defined such as to reproduce the experimental cell growth profile of fed-batch cultivation in jar fermenters. However, to confirm the biological appropriateness of our model, sensitivity analysis and experimental validation were required. Results We constructed an l-glutamic acid fermentation simulation model by removing sucAB, a gene encoding α-ketoglutarate dehydrogenase. We then performed systematic sensitivity analysis for l-glutamic acid production; the results of this process corresponded with previous experimental data regarding l-glutamic acid fermentation. Furthermore, it allowed us to predicted the possibility that accumulation of 3-phosphoglycerate in the cell would regulate the carbon flux into the TCA cycle and lead to an increase in the yield of l-glutamic acid via fermentation. We validated this hypothesis through a fermentation experiment involving a model l-glutamic acid-production strain, E. coli MG1655 ΔsucA in which the phosphoglycerate kinase gene had been amplified to cause accumulation of 3-phosphoglycerate. The observed increase in l-glutamic acid production verified the biologically meaningful predictive power of our dynamic metabolic simulation model. Conclusions In this study, dynamic simulation using a literature-based model was shown to be useful for elucidating the precise mechanisms involved in fermentation processes inside the cell. Further exhaustive sensitivity analysis will facilitate identification of novel factors involved in the metabolic regulation of amino acid fermentation. PMID:24053676

Metabolite changes during natural and lactic acid bacteria fermentations in pastes of soybeans and soybean–maize blends

PubMed Central

Ng'ong'ola-Manani, Tinna Austen; Østlie, Hilde Marit; Mwangwela, Agnes Mbachi; Wicklund, Trude

2014-01-01

The effect of natural and lactic acid bacteria (LAB) fermentation processes on metabolite changes in pastes of soybeans and soybean–maize blends was studied. Pastes composed of 100% soybeans, 90% soybeans and 10% maize, and 75% soybeans and 25% maize were naturally fermented (NFP), and were fermented by lactic acid bacteria (LFP). LAB fermentation processes were facilitated through back-slopping using a traditional fermented gruel, thobwa as an inoculum. Naturally fermented pastes were designated 100S, 90S, and 75S, while LFP were designated 100SBS, 90SBS, and 75SBS. All samples, except 75SBS, showed highest increase in soluble protein content at 48 h and this was highest in 100S (49%) followed by 90SBS (15%), while increases in 100SBS, 90S, and 75S were about 12%. Significant (P < 0.05) increases in total amino acids throughout fermentation were attributed to cysteine in 100S and 90S; and methionine in 100S and 90SBS. A 3.2% increase in sum of total amino acids was observed in 75SBS at 72 h, while decreases up to 7.4% in 100SBS at 48 and 72 h, 6.8% in 100S at 48 h and 4.7% in 75S at 72 h were observed. Increases in free amino acids throughout fermentation were observed in glutamate (NFP and 75SBS), GABA and alanine (LFP). Lactic acid was 2.5- to 3.5-fold higher in LFP than in NFP, and other organic acids detected were acetate and succinate. Maltose levels were the highest among the reducing sugars and were two to four times higher in LFP than in NFP at the beginning of the fermentation, but at 72 h, only fructose levels were significantly (P < 0.05) higher in LFP than in NFP. Enzyme activities were higher in LFP at 0 h, but at 72 h, the enzyme activities were higher in NFP. Both fermentation processes improved nutritional quality through increased protein and amino acid solubility and degradation of phytic acid (85% in NFP and 49% in LFP by 72 h). PMID:25493196

Production, optimization and characterization of lactic acid by Lactobacillus delbrueckii NCIM 2025 from utilizing agro-industrial byproduct (cane molasses).

PubMed

Srivastava, Abhinay Kumar; Tripathi, Abhishek Dutt; Jha, Alok; Poonia, Amrita; Sharma, Nitya

2015-06-01

In the present work Lactobacillus delbrueckii was used to utilize agro-industrial byproduct (cane molasses) for lactic acid production under submerged fermentation process. Screening of LAB was done by Fourier transform infra red spectroscopy (FTIR). Effect of different amino acids (DL-Phenylalanine, L-Lysine and DL-Aspartic acid) on the fermentation process was done by high performance liquid chromatography (HPLC). Central composite rotatable design (CCRD) was used to optimize the levels of three parameters viz. tween 80, amino acid and cane molasses concentration during fermentative production of lactic acid. Under optimum condition lactic acid production was enhanced from 55.89 g/L to 84.50 g/L. Further, validation showed 81.50 g/L lactic acid production. Scale up was done on 7.5 L fermentor. Productivity was found to be 3.40 g/L/h which was higher than previous studies with reduced fermentation time from 24 h to 12 h. Further characterization of lactic acid was done by FTIR.

Halobacterium sp. SP1(1) as a starter culture for accelerating fish sauce fermentation.

PubMed

Akolkar, A V; Durai, D; Desai, A J

2010-07-01

Application of Halobacterium sp. SP1(1) for the acceleration of fish sauce fermentation. Traditional fish sauce fermentation was mimicked using Halobacterium sp. SP1(1) as starter culture. Protease activity, peptide release and α-amino content (parameters used to monitor the progress of the fermentation) were high at day 10 in tests and day 20 in un-inoculated controls. The total protein and nitrogen contents were also high in tests compared with controls. The amino acid profile observed at the end of fermentation in experimental samples, when compared with the commercial sauce preparation, was found to be better with respect to flavour and aroma contributing amino acids as well as essential amino acid lysine. Microflora analysis of the final fish sauce revealed the absence of any nonhalophilic or halotolerant micro-organisms. The protease-producing halophilic isolates obtained from the fish sauce of eviscerated and uneviscerated controls were identified as Halobacterium sp. F1 and F2, respectively, by 16S rDNA sequence analysis. Exogenous augmentation of Halobacterium sp. SP1(1) accelerated the fish sauce fermentation process with an additive effect on the existing natural microflora present in the fish during fermentation. Halobacterium sp SP1(1), therefore, can be used as an important starter culture for accelerating the fish fermentation process, which is attributed to its extracellular protease. The present study is the first report on use of Halobacterium species as a starter culture for accelerating fish sauce fermentation. Use of halobacterial starter cultures may revolutionize the process in fish sauce industries by reducing the fermentation time and making the process more economical with improved nutritive value of product. Journal compilation © 2009 The Society for Applied Microbiology. No claim to Indian Government works.

The Impact of Single Amino Acids on Growth and Volatile Aroma Production by Saccharomyces cerevisiae Strains.

PubMed

Fairbairn, Samantha; McKinnon, Alexander; Musarurwa, Hannibal T; Ferreira, António C; Bauer, Florian F

2017-01-01

Nitrogen availability and utilization by Saccharomyces cerevisiae significantly influence fermentation kinetics and the production of volatile compounds important for wine aroma. Amino acids are the most important nitrogen source and have been classified based on how well they support growth. This study evaluated the effect of single amino acids on growth kinetics and major volatile production of two phenotypically different commercial wine yeast strains in synthetic grape must. Four growth parameters, lag phase, maximum growth rate, total biomass formation and time to complete fermentation were evaluated. In contrast with previous findings, in fermentative conditions, phenylalanine and valine supported growth well and asparagine supported it poorly. The four parameters showed good correlations for most amino acid treatments, with some notable exceptions. Single amino acid treatments resulted in the predictable production of aromatic compounds, with a linear correlation between amino acid concentration and the concentration of aromatic compounds that are directly derived from these amino acids. With the increased complexity of nitrogen sources, linear correlations were lost and aroma production became unpredictable. However, even in complex medium minor changes in amino acid concentration continued to directly impact the formation of aromatic compounds, suggesting that the relative concentration of individual amino acids remains a predictor of aromatic outputs, independently of the complexity of metabolic interactions between carbon and nitrogen metabolism and between amino acid degradation and utilization pathways.

The Impact of Single Amino Acids on Growth and Volatile Aroma Production by Saccharomyces cerevisiae Strains

PubMed Central

Fairbairn, Samantha; McKinnon, Alexander; Musarurwa, Hannibal T.; Ferreira, António C.; Bauer, Florian F.

2017-01-01

Nitrogen availability and utilization by Saccharomyces cerevisiae significantly influence fermentation kinetics and the production of volatile compounds important for wine aroma. Amino acids are the most important nitrogen source and have been classified based on how well they support growth. This study evaluated the effect of single amino acids on growth kinetics and major volatile production of two phenotypically different commercial wine yeast strains in synthetic grape must. Four growth parameters, lag phase, maximum growth rate, total biomass formation and time to complete fermentation were evaluated. In contrast with previous findings, in fermentative conditions, phenylalanine and valine supported growth well and asparagine supported it poorly. The four parameters showed good correlations for most amino acid treatments, with some notable exceptions. Single amino acid treatments resulted in the predictable production of aromatic compounds, with a linear correlation between amino acid concentration and the concentration of aromatic compounds that are directly derived from these amino acids. With the increased complexity of nitrogen sources, linear correlations were lost and aroma production became unpredictable. However, even in complex medium minor changes in amino acid concentration continued to directly impact the formation of aromatic compounds, suggesting that the relative concentration of individual amino acids remains a predictor of aromatic outputs, independently of the complexity of metabolic interactions between carbon and nitrogen metabolism and between amino acid degradation and utilization pathways. PMID:29312237

Amino acid profile and sensory characteristics of dry fermented pork loins produced with a mixture of probiotic starter cultures.

PubMed

Neffe-Skocińska, Katarzyna; Okoń, Anna; Kołożyn-Krajewska, Danuta; Dolatowski, Zbigniew

2017-07-01

Proteolysis is a biochemical process in dry-aged meat products where proteins are metabolized and broken down to polypeptides, peptides, and free amino acids. In the literature it is reported that an appropriate choice of probiotic starter culture limits proteolytic changes in dry-fermented meat products. In this study the combined effect of a mixture of probiotic starter cultures on the free amino acid profile, total count of lactic acid bacteria, and the sensory quality of dry-aged pork loins after fermentation and after storing the vacuum-packed samples was evaluated. LOCK900 and BB12 probiotic strains were the technologically best two-species mixture of starter cultures for the production of probiotic dry-aged pork loins. They allowed us to obtain products with high and stable bacterial count and acceptable sensory quality, both after 21 days of fermentation and after 2 months of cold storage. Changes in the free amino acid profile and increased intensity of the selected sensory attributes result from a significant share of probiotics in meat proteolysis occurring during fermentation and storage. The results suggest the relevance of using probiotic bacteria as a two-species starter culture for the production of dry-aged products. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Enhanced Bio-hydrogen Production from Protein Wastewater by Altering Protein Structure and Amino Acids Acidification Type

PubMed Central

Xiao, Naidong; Chen, Yinguang; Chen, Aihui; Feng, Leiyu

2014-01-01

Enhanced bio-hydrogen production from protein wastewater by altering protein structure and amino acids acidification type via pH control was investigated. The hydrogen production reached 205.2 mL/g-protein when protein wastewater was pretreated at pH 12 and then fermented at pH 10. The mechanism studies showed that pH 12 pretreatment significantly enhanced protein bio-hydrolysis during the subsequent fermentation stage as it caused the unfolding of protein, damaged the protein hydrogen bonding networks, and destroyed the disulfide bridges, which increased the susceptibility of protein to protease. Moreover, pH 10 fermentation produced more acetic but less propionic acid during the anaerobic fermentation of amino acids, which was consistent with the theory of fermentation type affecting hydrogen production. Further analyses of the critical enzymes, genes, and microorganisms indicated that the activity and abundance of hydrogen producing bacteria in the pH 10 fermentation reactor were greater than those in the control. PMID:24495932

Enhanced bio-hydrogen production from protein wastewater by altering protein structure and amino acids acidification type.

PubMed

Xiao, Naidong; Chen, Yinguang; Chen, Aihui; Feng, Leiyu

2014-02-05

Enhanced bio-hydrogen production from protein wastewater by altering protein structure and amino acids acidification type via pH control was investigated. The hydrogen production reached 205.2 mL/g-protein when protein wastewater was pretreated at pH 12 and then fermented at pH 10. The mechanism studies showed that pH 12 pretreatment significantly enhanced protein bio-hydrolysis during the subsequent fermentation stage as it caused the unfolding of protein, damaged the protein hydrogen bonding networks, and destroyed the disulfide bridges, which increased the susceptibility of protein to protease. Moreover, pH 10 fermentation produced more acetic but less propionic acid during the anaerobic fermentation of amino acids, which was consistent with the theory of fermentation type affecting hydrogen production. Further analyses of the critical enzymes, genes, and microorganisms indicated that the activity and abundance of hydrogen producing bacteria in the pH 10 fermentation reactor were greater than those in the control.

Comparative genome analysis of the candidate functional starter culture strains Lactobacillus fermentum 222 and Lactobacillus plantarum 80 for controlled cocoa bean fermentation processes.

PubMed

Illeghems, Koen; De Vuyst, Luc; Weckx, Stefan

2015-10-12

Lactobacillus fermentum 222 and Lactobacillus plantarum 80, isolates from a spontaneous Ghanaian cocoa bean fermentation process, proved to be interesting functional starter culture strains for cocoa bean fermentations. Lactobacillus fermentum 222 is a thermotolerant strain, able to dominate the fermentation process, thereby converting citrate and producing mannitol. Lactobacillus plantarum 80 is an acid-tolerant and facultative heterofermentative strain that is competitive during cocoa bean fermentation processes. In this study, whole-genome sequencing and comparative genome analysis was used to investigate the mechanisms of these strains to dominate the cocoa bean fermentation process. Through functional annotation and analysis of the high-coverage contigs obtained through 454 pyrosequencing, plantaricin production was predicted for L. plantarum 80. For L. fermentum 222, genes encoding a complete arginine deiminase pathway were attributed. Further, in-depth functional analysis revealed the capacities of these strains associated with carbohydrate and amino acid metabolism, such as the ability to use alternative external electron acceptors, the presence of an extended pyruvate metabolism, and the occurrence of several amino acid conversion pathways. A comparative genome sequence analysis using publicly available genome sequences of strains of the species L. plantarum and L. fermentum revealed unique features of both strains studied. Indeed, L. fermentum 222 possessed genes encoding additional citrate transporters and enzymes involved in amino acid conversions, whereas L. plantarum 80 is the only member of this species that harboured a gene cluster involved in uptake and consumption of fructose and/or sorbose. In-depth genome sequence analysis of the candidate functional starter culture strains L. fermentum 222 and L. plantarum 80 revealed their metabolic capacities, niche adaptations and functionalities that enable them to dominate the cocoa bean fermentation process. Further, these results offered insights into the cocoa bean fermentation ecosystem as a whole and will facilitate the selection of appropriate starter culture strains for controlled cocoa bean fermentation processes.

Enhanced Bio-hydrogen Production from Protein Wastewater by Altering Protein Structure and Amino Acids Acidification Type

NASA Astrophysics Data System (ADS)

Xiao, Naidong; Chen, Yinguang; Chen, Aihui; Feng, Leiyu

2014-02-01

Enhanced bio-hydrogen production from protein wastewater by altering protein structure and amino acids acidification type via pH control was investigated. The hydrogen production reached 205.2 mL/g-protein when protein wastewater was pretreated at pH 12 and then fermented at pH 10. The mechanism studies showed that pH 12 pretreatment significantly enhanced protein bio-hydrolysis during the subsequent fermentation stage as it caused the unfolding of protein, damaged the protein hydrogen bonding networks, and destroyed the disulfide bridges, which increased the susceptibility of protein to protease. Moreover, pH 10 fermentation produced more acetic but less propionic acid during the anaerobic fermentation of amino acids, which was consistent with the theory of fermentation type affecting hydrogen production. Further analyses of the critical enzymes, genes, and microorganisms indicated that the activity and abundance of hydrogen producing bacteria in the pH 10 fermentation reactor were greater than those in the control.

Influence of thermally processed carbohydrate/amino acid mixtures on the fermentation by Saccharomyces cerevisiae.

PubMed

Tauer, Andreas; Elss, Sandra; Frischmann, Matthias; Tellez, Patricia; Pischetsrieder, Monika

2004-04-07

The production of alcoholic beverages such as Tequila, Mezcal, whiskey, or beer includes the fermentation of a mash containing Maillard reaction products. Because excessive heating of the mash can lead to complications during the following fermentation step, the impact of Maillard products on the metabolism of Saccharomyces cerevisiae was investigated. For this purpose, fermentation was carried out in a model system in the presence and absence of Maillard reaction products and formation of ethanol served as a marker for the progression of fermentation. We found that increasing amounts of Maillard products reduced the formation of ethanol up to 80%. This effect was dependent on the pH value during the Maillard reaction, reaction time, as well as the carbohydrate and amino acid component used for the generation of Maillard reaction products. Another important factor is the pH value during fermentation: The inhibitory effect of Maillard products was not detectable at a pH of 4 and increased with higher pH-values. These findings might be of relevance for the production of above-mentioned beverages.

Comparison between the amino acid, fatty acid, mineral and nutritional quality of raw, germinated and fermented African locust bean (Parkia biglobosa) flour.

PubMed

Ijarotimi, Oluwole Steve; Keshinro, Oluremi Olufunke

2012-04-02

The most popular form of utilization of African locust bean (ALB) is in its traditional fermentation food condiment (iru/dawadawa), which adds protein to a protein-poor diet and also as medicine. In view of the nutritive values of ALB, the present study therefore aimed at investigating the effect of germination and fermentation on the nutritional quality of ALB flour. The ALB was obtained from a local market in Akure, Nigeria. The seeds were divided into three portions, and treated as raw African locust bean (RALB), germinated African locust bean (GALB) and fermented African locust bean (FALB) respectively. Each of the samples was milled, sieved and analysed for chemical, functional properties and nutritional qualities using standard methods. Some most important results of the chemical analysis were as follows: protein content range between 33.64 ±0.41 - 41.49 ±1.89 g/100 g, while the energy value was between 442.79 ±2.32 - 457.20 ±2.15 kcal. The P/Ca and Na/K ratio of the RALB were higher than other fl our samples respectively. Total essential amino acid was between 29.960-27.514 mg/100 g. Protein efficiency ratio (PER) was between 1.78-1.87; essential amino acid index 31.43-34.75%; while biological values were 22.56-26.18%. The dominant fatty acid (FA) composition of the samples was linoleic with 33.687%, 31.578% and 28.7% for RALB, GALB and FALB respectively; while the least was lauric acid. The polyunsaturated/saturated FA ratio ranges between 0.589-0.718. The antinutrient concentration of fermented flour sample was significantly reduced than other food samples. The present study investigated the effect of germination and fermentation on the nutritional quality of ALB flour. The finding showed that fermentation technique significantly reduced antinutrient concentration and also improved the nutrient composition, particularly amino acid profile of ALB flour.

Fermentable soluble fibres spare amino acids in healthy dogs fed a low-protein diet.

PubMed

Wambacq, Wendy; Rybachuk, Galena; Jeusette, Isabelle; Rochus, Kristel; Wuyts, Brigitte; Fievez, Veerle; Nguyen, Patrick; Hesta, Myriam

2016-06-28

Research in cats has shown that increased fermentation-derived propionic acid and its metabolites can be used as alternative substrates for gluconeogenesis, thus sparing amino acids for other purposes. This amino acid sparing effect could be of particular interest in patients with kidney or liver disease, where this could reduce the kidneys'/liver's burden of N-waste removal. Since dogs are known to have a different metabolism than the obligatory carnivorous cat, the main objective of this study was to assess the possibility of altering amino acid metabolism through intestinal fermentation in healthy dogs. This was studied by supplementing a low-protein diet with fermentable fibres, hereby providing an initial model for future studies in dogs suffering from renal/liver disease. Eight healthy dogs were randomly assigned to one of two treatment groups: sugar beet pulp and guar gum mix (SF: soluble fibre, estimated to mainly stimulate propionic acid production) or cellulose (IF: insoluble fibre). Treatments were incorporated into a low-protein (17 %) extruded dry diet in amounts to obtain similar total dietary fibre (TDF) contents for both diets (9.4 % and 8.2 % for the SF and IF diet, respectively) and were tested in a 4-week crossover feeding trial. Apparent faecal nitrogen digestibility and post-prandial fermentation metabolites in faeces and plasma were evaluated. Dogs fed the SF diet showed significantly higher faecal excretion of acetic and propionic acid, resulting in a higher total SCFA excretion compared to IF. SF affected the three to six-hour postprandial plasma acylcarnitine profile by significantly increasing AUC of acetyl-, propionyl-, butyryl- + isobutyryl-, 3-OH-butyryl-, 3-OH-isovaleryl- and malonyl-L-carnitine. Moreover, the amino acid plasma profile at that time was modified as leucine + isoleucine concentrations were significantly increased by SF, and a similar trend for phenylalanine and tyrosine's AUC was found. These results indicate that guar gum and sugar beet pulp supplementation diminishes postprandial use of amino acids favoring instead the use of short-chain fatty acids as substrate for the tricarboxylic acid (TCA) cycle. Further research is warranted to investigate the amino acid sparing effect of fermentable fibres in dogs with kidney/liver disease.

Vine-shoot waste aqueous extract applied as foliar fertilizer to grapevines: Effect on amino acids and fermentative volatile content.

PubMed

Sánchez-Gómez, R; Garde-Cerdán, T; Zalacain, A; Garcia, R; Cabrita, M J; Salinas, M R

2016-04-15

The aim of this work was to study the influence of foliar applications of different wood aqueous extracts on the amino acid content of musts and wines from Airén variety; and to study their relationship with the volatile compounds formed during alcoholic fermentation. For this purpose, the foliar treatments proposed were a vine-shoot aqueous extract applied in one and two times, and an oak extract which was only applied once. Results obtained show the potential of Airén vine-shoot waste aqueous extracts to be used as foliar fertilizer, enhancing the wine amino acid content especially when they were applied once. Similar results were observed with the aqueous oak extract. Regarding wine fermentative volatile compounds, there is a close relationship between musts and their wines amino acid content allowing us to discuss about the role of proline during the alcoholic fermentation and the generation of certain volatiles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Identification of key micro-organisms involved in Douchi fermentation by statistical analysis and their use in an experimental fermentation.

PubMed

Chen, C; Xiang, J Y; Hu, W; Xie, Y B; Wang, T J; Cui, J W; Xu, Y; Liu, Z; Xiang, H; Xie, Q

2015-11-01

To screen and identify safe micro-organisms used during Douchi fermentation, and verify the feasibility of producing high-quality Douchi using these identified micro-organisms. PCR-denaturing gradient gel electrophoresis (DGGE) and automatic amino-acid analyser were used to investigate the microbial diversity and free amino acids (FAAs) content of 10 commercial Douchi samples. The correlations between microbial communities and FAAs were analysed by statistical analysis. Ten strains with significant positive correlation were identified. Then an experiment on Douchi fermentation by identified strains was carried out, and the nutritional composition in Douchi was analysed. Results showed that FAAs and relative content of isoflavone aglycones in verification Douchi samples were generally higher than those in commercial Douchi samples. Our study indicated that fungi, yeasts, Bacillus and lactic acid bacteria were the key players in Douchi fermentation, and with identified probiotic micro-organisms participating in fermentation, a higher quality Douchi product was produced. This is the first report to analyse and confirm the key micro-organisms during Douchi fermentation by statistical analysis. This work proves fermentation micro-organisms to be the key influencing factor of Douchi quality, and demonstrates the feasibility of fermenting Douchi using identified starter micro-organisms. © 2015 The Society for Applied Microbiology.

Immunoreactivity reduction of soybean meal by fermentation, effect on amino acid composition and antigenicity of commercial soy products.

PubMed

Song, Y-S; Frias, J; Martinez-Villaluenga, C; Vidal-Valdeverde, C; de Mejia, E Gonzalez

2008-05-15

Food allergy has become a public health problem that continues to challenge both the consumer and the food industry. The objectives of this study were to evaluate the reduction of immunoreactivity by natural and induced fermentation of soybean meal (SBM) with Lactobacillus plantarum, Bifidobacterium lactis, Saccharomyces cereviseae, and to assess the effect on amino acid concentration. Immunoreactivity of commercially available fermented soybean products and ingredients was also evaluated. ELISA and western blot were used to measure IgE immunoreactivity using plasma from soy sensitive individuals. Commercial soy products included tempeh, miso and yogurt. Fermented SBM showed reduced immunoreactivity to human plasma, particularly if proteins were <20kDa. S. cereviseae and naturally fermented SBM showed the highest reduction in IgE immunoreactivity, up to 89% and 88%, respectively, against human pooled plasma. When SBM was subjected to fermentation with different microorganisms, most of the total amino acids increased significantly (p<0.05) and only few of them suffered a decrease depending on the type of fermentation. All commercial soy containing products tested showed very low immunoreactivity. Thus, fermentation can decrease soy immunoreactivity and can be optimized to develop nutritious hypoallergenic soy products. However, the clinical relevance of these findings needs to be determined by human challenge studies. Copyright © 2007 Elsevier Ltd. All rights reserved.

Microbial behavior and changes in food constituents during fermentation of Japanese sourdoughs with different rye and wheat starting materials.

PubMed

Fujimoto, Akihito; Ito, Keisuke; Itou, Madoka; Narushima, Noriko; Ito, Takayuki; Yamamoto, Akihisa; Hirayama, Satoru; Furukawa, Soichi; Morinaga, Yasushi; Miyamoto, Takahisa

2018-01-01

Sourdough is a food item made by kneading grain flour and water together and allowing fermentation through the action of lactic acid bacteria (Lactobacillales) and yeast. Typically, Japanese bakeries make sourdough with rye flour, wheat flour, malt extract, and water and allow spontaneous fermentation for 6 days. We compared the microbial behavior and food components, such as organic acids, sugars, and free amino acids, of sourdoughs made using two different rye and wheat flours during the 6-day fermentation period. Comparisons were made for two types of rye and wheat flours, using different production sites and different milling, distribution, and storage conditions. The microbial count was evaluated using different culture media. All sourdough types showed a significant increase in lactic acid levels on fermentation day 2 and a decrease in free amino acid levels on day 4. Low overall lactic acid production and little fluctuation in sugar levels occurred in sourdough made from French ingredients. For sourdough made from Japanese ingredients, sugar levels (chiefly glucose, sucrose, and maltose) declined on fermentation day 1, increased on day 2, and declined by day 5. With the French ingredients, no yeast cells were detected until day 3, and many acid precursors of sourdough flavor components were detected. Yet with the Japanese ingredients, 10 6 /g yeast cells were detected on days 3-5, as well as sourdough-flavor esters and alcohols. Differences in raw material quality affected the microbial behavior and changes in food constituents during the fermentation process and, consequently, the sourdough flavor. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Lysine Fermentation: History and Genome Breeding.

PubMed

Ikeda, Masato

Lysine fermentation by Corynebacterium glutamicum was developed in 1958 by Kyowa Hakko Kogyo Co. Ltd. (current Kyowa Hakko Bio Co. Ltd.) and is the second oldest amino acid fermentation process after glutamate fermentation. The fundamental mechanism of lysine production, discovered in the early stages of the process's history, gave birth to the concept known as "metabolic regulatory fermentation," which is now widely applied to metabolite production. After the development of rational metabolic engineering, research on lysine production first highlighted the need for engineering of the central metabolism from the viewpoints of precursor supply and NADPH regeneration. Furthermore, the existence of active export systems for amino acids was first demonstrated for lysine in C. glutamicum, and this discovery has resulted in the current recognition of such exporters as an important consideration in metabolite production. Lysine fermentation is also notable as the first process to which genomics was successfully applied to improve amino acid production. The first global "genome breeding" strategy was developed using a lysine producer as a model; this has since led to new lysine producers that are more efficient than classical industrial producers. These advances in strain development technology, combined with recent systems-level approaches, have almost achieved the optimization of entire cellular systems as cell factories for lysine production. In parallel, the continuous improvement of the process has resulted not only in fermentation processes with reduced load on downstream processing but also in commercialization of various product forms according to their intended uses. Nowadays lysine fermentation underpins a giant lysine demand of more than 2 million metric tons per year.

Use of Tetragenococcus halophilus as a starter culture for flavor improvement in fish sauce fermentation.

PubMed

Udomsil, Natteewan; Rodtong, Sureelak; Choi, Yeung Joon; Hua, Yanglin; Yongsawatdigul, Jirawat

2011-08-10

The potential of Tetragenococcus halophilus as a starter culture for flavor improvement in fish sauce fermentation was elucidated. Four strains of T. halophilus isolated from fish sauce mashes were inoculated to anchovy mixed with 25% NaCl with an approximate cell count of 10(6) CFU/mL. The α-amino content of 6-month-old fish sauce samples inoculated with T. halophilus was 780-784 mM. The addition of T. halophilus MRC10-1-3 and T. halophilus MCD10-5-10 resulted in a reduction of histamine (P < 0.05). Fish sauce inoculated with T. halophilus showed high contents of total amino acids with predominantly high glutamic acid. Major volatile compounds in fish sauce were 2-methylpropanal, 2-methylbutanal, 3-methylbutanal, and benzaldehyde. T. halophilus-inoculated fish sauce samples demonstrated the ability to reduce dimethyl disulfide, a compound contributing to a fecal note. The use of T. halophilus for fish sauce fermentation improves amino acid profiles and volatile compounds as well as reduces biogenic amine content of a fish sauce product.

Role of jeotgal, a Korean traditional fermented fish sauce, in microbial dynamics and metabolite profiles during kimchi fermentation.

PubMed

Jung, Min Young; Kim, Tae-Woon; Lee, Changsu; Kim, Joon Yong; Song, Hye Seon; Kim, Yeon Bee; Ahn, Seung Woo; Kim, Ju Seok; Roh, Seong Woon; Lee, Se Hee

2018-11-01

We investigated the effects of jeotgal (fermented fish sauce) on kimchi fermentation, with or without saeu-jeot and myeolchi-jeot. Bacterial community analysis showed that Leuconostoc, Weissella, Lactobacillus, and Tetragenococcus were the dominant genera; however, their succession depended on the presence of jeotgal. Leuconostoc gasicomitatum was the dominant species in kimchi without jeotgal, whereas Weissella koreensis and Lactobacillus sakei were the dominant species in kimchi with myeolchi-jeot and saeu-jeot, respectively. Metabolite analysis, using 1 H NMR, showed that the amounts of amino acids and gamma-aminobutyric acid (GABA) were higher in kimchi with jeotgal. Increases in acetate, lactate, and mannitol contents depended on fructose consumption and were more rapid in kimchi with jeotgal. Moreover, the consumption of various amino acids affected the increase in kimchi LAB. Thus, the role of jeotgal in kimchi fermentation was related to enhancement of taste, the amino acid source, and the increases in levels of functional metabolites. Copyright © 2018. Published by Elsevier Ltd.

Metabolic strategies of beer spoilage lactic acid bacteria in beer.

PubMed

Geissler, Andreas J; Behr, Jürgen; von Kamp, Kristina; Vogel, Rudi F

2016-01-04

Beer contains only limited amounts of readily fermentable carbohydrates and amino acids. Beer spoilage lactic acid bacteria (LAB) have to come up with metabolic strategies in order to deal with selective nutrient content, high energy demand of hop tolerance mechanisms and a low pH. The metabolism of 26 LAB strains of 6 species and varying spoilage potentialwas investigated in order to define and compare their metabolic capabilities using multivariate statistics and outline possible metabolic strategies. Metabolic capabilities of beer spoilage LAB regarding carbohydrate and amino acids did not correlate with spoilage potential, but with fermentation type (heterofermentative/homofermentative) and species. A shift to mixed acid fermentation by homofermentative (hof) Pediococcus claussenii and Lactobacillus backii was observed as a specific feature of their growth in beer. For heterofermentative (hef) LAB a mostly versatile carbohydrate metabolism could be demonstrated, supplementing the known relevance of organic acids for their growth in beer. For hef LAB a distinct amino acid metabolism, resulting in biogenic amine production, was observed, presumably contributing to energy supply and pH homeostasis.

Peptide (Lys-Leu) and amino acids (Lys and Leu) supplementations improve physiological activity and fermentation performance of brewer's yeast during very high-gravity (VHG) wort fermentation.

PubMed

Yang, Huirong; Zong, Xuyan; Cui, Chun; Mu, Lixia; Zhao, Haifeng

2017-12-22

Lys and Leu were generally considered as the key amino acids for brewer's yeast during beer brewing. In the present study, peptide Lys-Leu and a free amino acid (FAA) mixture of Lys and Leu (Lys + Leu) were supplemented in 24 °P wort to examine their effects on physiological activity and fermentation performance of brewer's yeast during very high-gravity (VHG) wort fermentation. Results showed that although both peptide Lys-Leu and their FAA mixture supplementations could increase the growth and viability, intracellular trehalose and glycerol content, wort fermentability, and ethanol content for brewer's yeast during VHG wort fermentation, and peptide was better than their FAA mixture at promoting growth and fermentation for brewer's yeast when the same dose was kept. Moreover, peptide Lys-Leu supplementation significantly increased the assimilation of Asp, but decreased the assimilation of Gly, Ala, Val, (Cys)2, Ile, Leu, Tyr, Phe, Lys, Arg, and Pro. However, the FAA mixture supplementation only promoted the assimilation of Lys and Leu, while reduced the absorption of total amino acids to a greater extent. Thus, the peptide Lys-Leu was more effective than their FAA mixture on the improvement of physiological activity, fermentation performance, and nitrogen metabolism of brewer's yeast during VHG wort fermentation. © 2017 International Union of Biochemistry and Molecular Biology, Inc.

Determination of Amino Acids in Cell Culture and Fermentation Broth Media Using Anion-Exchange Chromatography with Integrated Pulsed Amperometric Detection

PubMed Central

Hanko, Valoran P.; Heckenberg, Andrea; Rohrer, Jeffrey S.

2004-01-01

Anion-exchange chromatography with integrated pulsed amperometric detection (AE-IPAD) separates and directly detects amino acids, carbohydrates, alditols, and glycols in the same injection without pre- or post-column derivatization. These separations use a combination of NaOH and NaOH/sodium acetate eluents. We previously published the successful use of this technique, also known as AAA-Direct, to determine free amino acids in cell culture and fermentation broth media. We showed that retention of carbohydrates varies with eluent NaOH concentration differently than amino acids, and thus separations can be optimized by varying the initial NaOH concentration and its duration. Unfortunately, some amino acids eluting in the acetate gradient portion of the method were not completely resolved from system-related peaks and from unknown peaks in complex cell culture and fermentation media. In this article, we present changes in method that improve amino acid resolution and system ruggedness. The success of these changes and their compatibility with the separations previously designed for fermentation and cell culture are demonstrated with yeast extract-peptone-dextrose broth, M199, Dulbecco’s modified Eagle’s (with F-12), L-15 (Leibovitz), and McCoy’s 5A cell culture media. PMID:15585828

Isolation and Characterization of a Gene Specific to Lager Brewing Yeast That Encodes a Branched-Chain Amino Acid Permease

PubMed Central

Kodama, Yukiko; Omura, Fumihiko; Ashikari, Toshihiko

2001-01-01

We found two types of branched-chain amino acid permease gene (BAP2) in the lager brewing yeast Saccharomyces pastorianus BH-225 and cloned one type of BAP2 gene (Lg-BAP2), which is identical to that of Saccharomyces bayanus (by-BAP2-1). The other BAP2 gene of the lager brewing yeast (cer-BAP2) is very similar to the Saccharomyces cerevisiae BAP2 gene. This result substantiates the notion that lager brewing yeast is a hybrid of S. cerevisiae and S. bayanus. The amino acid sequence homology between S. cerevisiae Bap2p and Lg-Bap2p was 88%. The transcription of Lg-BAP2 was not induced by the addition of leucine to the growth medium, while that of cer-BAP2 was induced. The transcription of Lg-BAP2 was repressed by the presence of ethanol and weak organic acid, while that of cer-BAP2 was not affected by these compounds. Furthermore, Northern analysis during beer fermentation revealed that the transcription of Lg-BAP2 was repressed at the beginning of the fermentation, while cer-BAP2 was highly expressed throughout the fermentation. These results suggest that the transcription of Lg-BAP2 is regulated differently from that of cer-BAP2 in lager brewing yeasts. PMID:11472919

Estimating the effect of fermentation yeast on distillers grains protein

USDA-ARS?s Scientific Manuscript database

Distillers dried grains with solubles (DDGS) is the key co-product of bio-ethanol production from grains. Major factors affecting its quality and market values include protein quantity (concentration) and quality (amino acid composition). Yet, the effect of fermentation yeast on DDGS quality has no...

Gamma-amino butyric acid (GABA) synthesis of Lactobacillus in fermentation of defatted rice bran extract

NASA Astrophysics Data System (ADS)

Dat, Lai Quoc; Ngan, Tran Thi Kim; Nu, Nguyen Thi Xuan

2017-09-01

This research focused on the synthesis of GABA by Lactobacillus bacteria in fermentation of defatted rice bran extract without adding glutamate. Two strains of Lactobacillus were investigated into capacity of GABA synthesis. Result indicates that, Lactobacillus brevis VTCC - B - 454 exhibited the higher capacity of GABA synthesis in fermentation of defatted rice bran extract than that of Lactobacillus plantarum VTCC - B - 890. Total dissolved solid (TDS), free amino acids (AA) and reducing sugar (RS) contents in fermentation of defatted rice bran extract with two strains also significantly decreased. At pH 5 and 9 %w/w of TDS content in defatted rice bran extract, Lactobacillus brevis VTCC - B - 454 accumulated 2,952 ppm of GABA in 24 hours of fermentation. The result implies that fermentation with Lactobacillus brevis VTCC - B - 454 can be applied for GABA production from defatted rice bran extract.

[Metabolic pattern of pig hindgut bacteria on aromatic amino acids by an in vitro fermentation method].

PubMed

Ma, Meilei; He, Xiangyu; Zhu, Weiyun

2016-11-04

This experiment was conducted to study different metabolic patterns of pig hindgut bacteria on aromatic amino acids by an in vitro fermentation method. Ileum, cecum and colon chyme in Duroc, Landrace and Yorkshire goods hybridization pigs were taken as inoculum. The single aromatic amino acid concentration was kept 10 mmol/L in fermentation flask. Then the fermentation flask was incubated at 37℃ for 24 h. Gas production was measured at 4, 8, 12, 16 and 24 h, and samples of fermentation collected at 0 h and 24 h were used to measure ammonia nitrogen NH3-N and microbial crude protein (MCP). Denaturing gradient gel electrophoresis (DGGE) and real-time PCR were used to monitor and quantify the development of bacteria community in zymotic fluid.[ The concentrations of NH3-N and MCP were significantly affected by aromatic amino acids and intestinal segments (P<0.01). Intestinal segments also affected gas production (GP) significantly (P0.01). NH3-N, MCP and GP were affected by interaction of aromatic amino acids and intestinal segments. DGGE analysis showed bacteria of aromatic amino acids shared amount of bands together, especially similarity analysis of DGGE profile of Phe and Tyr in ileum, Tyr and Trp in colon were 87.9% and 80.5% separately. Shannon diversity indices analysis revealed that aromatic amino acids in cecum and colon varied significantly (P<0.05). Real-time PCR results showed that the quantity of total bacteria were affected by aromatic amino acids and intestinal segments significantly (P<0.05). The potential as proportion of different aromatic amino acids are different. Compared with Trp and Phe, the diversity of bacteria utilizing Tyr in cecum or colon is low; compared with Tyr and Trp, a large number of Phe participated in synthesizing bacteria.The fermentation pattern of specific aromatic amino acids in different intestinal segment was unique. Compared with ileum and cecum, much more aromatic amino acids participated in the synthesis of bacteria in colon.

Improved ethanol tolerance of Saccharomyces cerevisiae in mixed cultures with Kluyveromyces lactis on high-sugar fermentation.

PubMed

Yamaoka, Chizuru; Kurita, Osamu; Kubo, Tomoko

2014-12-01

The influence of non-Saccharomyces yeast, Kluyveromyces lactis, on metabolite formation and the ethanol tolerance of Saccharomyces cerevisiae in mixed cultures was examined on synthetic minimal medium containing 20% glucose. In the late stage of fermentation after the complete death of K. lactis, S. cerevisiae in mixed cultures was more ethanol-tolerant than that in pure culture. The chronological life span of S. cerevisiae was shorter in pure culture than mixed cultures. The yeast cells of the late stationary phase both in pure and mixed cultures had a low buoyant density with no significant difference in the non-quiescence state between both cultures. In mixed cultures, the glycerol contents increased and the alanine contents decreased when compared with the pure culture of S. cerevisiae. The distinctive intracellular amino acid pool concerning its amino acid concentrations and its amino acid composition was observed in yeast cells with different ethanol tolerance in the death phase. Co-cultivation of K. lactis seems to prompt S. cerevisiae to be ethanol tolerant by forming opportune metabolites such as glycerol and alanine and/or changing the intracellular amino acid pool. Copyright © 2014 Elsevier GmbH. All rights reserved.

Influence of foliar riboflavin applications to vineyard on grape amino acid content.

PubMed

González-Santamaría, Rosario; Ruiz-González, Rubén; Nonell, Santi; Garde-Cerdán, Teresa; Pérez-Álvarez, Eva P

2018-02-01

Nitrogen is an important element for grapevine and winemaking, which affects plant development, grape juice fermentation and has a potential effect in modulating wine quality. The aim was to study the influence of foliar applications of riboflavin (vitamin B2) to vineyard on grape nitrogen composition. This vitamin has a reported capacity to protect different plant species, but its application to favor grape and grape juice quality had not previously been studied. This work reports the oenological properties and the effect on amino acid concentration of grape juices obtained from grapes treated with riboflavin at two different doses compared to control. Results showed that probable alcohol, malic acid, color intensity and hue had significant differences when the riboflavin treatments were applied. Most of the amino acids presented the highest concentrations when the lowest riboflavin dose was used. These results are promising in terms of fermentation development and grape juice nitrogen composition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of methyl jasmonate application to grapevine leaves on grape amino acid content.

PubMed

Garde-Cerdán, Teresa; Portu, Javier; López, Rosa; Santamaría, Pilar

2016-07-15

Over the last few years, considerable attention has been paid to the application of elicitors to vineyard. However, research about the effect of elicitors on grape amino acid content is scarce. Therefore, the aim of this study was to evaluate the influence of foliar application of methyl jasmonate on must amino acid content. Results revealed that total amino acid content was not modified by the application of methyl jasmonate. However, the individual content of certain amino acids was increased as consequence of methyl jasmonate foliar application, i.e., histidine, serine, tryptophan, phenylalanine, tyrosine, asparagine, methionine, and lysine. Among them, phenylalanine content was considerably increased; this amino acid is precursor of phenolic and aromatic compounds. In conclusion, foliar application of methyl jasmonate improved must nitrogen composition. This finding suggests that methyl jasmonate treatment might be conducive to obtain wines of higher quality since must amino acid composition could affect the wine volatile composition and the fermentation kinetics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Very high gravity ethanol and fatty acid production of Zymomonas mobilis without amino acid and vitamin.

PubMed

Wang, Haoyong; Cao, Shangzhi; Wang, William Tianshuo; Wang, Kaven Tianyv; Jia, Xianhui

2016-06-01

Very high gravity (VHG) fermentation is the mainstream technology in ethanol industry, which requires the strains be resistant to multiple stresses such as high glucose concentration, high ethanol concentration, high temperature and harsh acidic conditions. To our knowledge, it was not reported previously that any ethanol-producing microbe showed a high performance in VHG fermentations without amino acid and vitamin. Here we demonstrate the engineering of a xylose utilizing recombinant Zymomonas mobilis for VHG ethanol fermentations. The recombinant strain can produce ethanol up to 136 g/L without amino acid and vitamin with a theoretical yield of 90 %, which is significantly superior to that produced by all the reported ethanol-producing strains. The intracellular fatty acids of the bacterial were about 16 % of the bacterial dry biomass, with the ratio of ethanol:fatty acids was about 273:1 (g/g). The recombinant strain was achieved by a multivariate-modular strategy tackles with the multiple stresses which are closely linked to the ethanol productivity of Z. mobilis. The over-expression of metB/yfdZ operon enabled the growth of the recombinant Z. mobilis in a chemically defined medium without amino acid and vitamin; and the fatty acids overproduction significantly increased ethanol tolerance and ethanol production. The coupled production of ethanol with fatty acids of the Z. mobilis without amino acid and vitamin under VHG fermentation conditions may permit a significant reduction of the production cost of ethanol and microbial fatty acids.

Metabolic Responses of Saccharomyces cerevisiae to Valine and Ammonium Pulses during Four-Stage Continuous Wine Fermentations

PubMed Central

Clement, T.; Perez, M.; Mouret, J. R.; Sanchez, I.; Sablayrolles, J. M.

2013-01-01

Nitrogen supplementation, which is widely used in winemaking to improve fermentation kinetics, also affects the products of fermentation, including volatile compounds. However, the mechanisms underlying the metabolic response of yeast to nitrogen additions remain unclear. We studied the consequences for Saccharomyces cerevisiae metabolism of valine and ammonium pulses during the stationary phase of four-stage continuous fermentation (FSCF). This culture technique provides cells at steady state similar to that of the stationary phase of batch wine fermentation. Thus, the FSCF device is an appropriate and reliable tool for individual analysis of the metabolic rerouting associated with nutrient additions, in isolation from the continuous evolution of the environment in batch processes. Nitrogen additions, irrespective of the nitrogen-containing compound added, substantially modified the formation of fermentation metabolites, including glycerol, succinate, isoamyl alcohol, propanol, and ethyl esters. This flux redistribution, fulfilling the requirements for precursors of amino acids, was consistent with increased protein synthesis resulting from increased nitrogen availability. Valine pulses, less efficient than ammonium addition in increasing the fermentation rate, were followed by a massive conversion of this amino acid in isobutanol and isobutyl acetate through the Ehrlich pathway. However, additional routes were involved in valine assimilation when added in stationary phase. Overall, we found that particular metabolic changes may be triggered according to the nature of the amino acid supplied, in addition to the common response. Both these shared and specific modifications should be considered when designing strategies to modulate the production of volatile compounds, a current challenge for winemakers. PMID:23417007

Metabolic responses of Saccharomyces cerevisiae to valine and ammonium pulses during four-stage continuous wine fermentations.

PubMed

Clement, T; Perez, M; Mouret, J R; Sanchez, I; Sablayrolles, J M; Camarasa, C

2013-04-01

Nitrogen supplementation, which is widely used in winemaking to improve fermentation kinetics, also affects the products of fermentation, including volatile compounds. However, the mechanisms underlying the metabolic response of yeast to nitrogen additions remain unclear. We studied the consequences for Saccharomyces cerevisiae metabolism of valine and ammonium pulses during the stationary phase of four-stage continuous fermentation (FSCF). This culture technique provides cells at steady state similar to that of the stationary phase of batch wine fermentation. Thus, the FSCF device is an appropriate and reliable tool for individual analysis of the metabolic rerouting associated with nutrient additions, in isolation from the continuous evolution of the environment in batch processes. Nitrogen additions, irrespective of the nitrogen-containing compound added, substantially modified the formation of fermentation metabolites, including glycerol, succinate, isoamyl alcohol, propanol, and ethyl esters. This flux redistribution, fulfilling the requirements for precursors of amino acids, was consistent with increased protein synthesis resulting from increased nitrogen availability. Valine pulses, less efficient than ammonium addition in increasing the fermentation rate, were followed by a massive conversion of this amino acid in isobutanol and isobutyl acetate through the Ehrlich pathway. However, additional routes were involved in valine assimilation when added in stationary phase. Overall, we found that particular metabolic changes may be triggered according to the nature of the amino acid supplied, in addition to the common response. Both these shared and specific modifications should be considered when designing strategies to modulate the production of volatile compounds, a current challenge for winemakers.

Aroma improvement by repeated freeze-thaw treatment during Tuber melanosporum fermentation

PubMed Central

Xiao, Deng-Rong; Liu, Rui-Sang; He, Long; Li, Hong-Mei; Tang, Ya-Ling; Liang, Xin-Hua; Chen, Tao; Tang, Ya-Jie

2015-01-01

The aroma attributes of sulfurous, mushroom and earthy are the most important characteristics of the aroma of Tuber melanosporum. However, these three aroma attributes are absent in the T. melanosporum fermentation system. To improve the quality of the aroma, repeated freeze-thaw treatment (RFTT) was adopted to affect the interplay of volatile organic compounds (VOCs). Using RFTT, not only was the score on the hedonic scale of the aroma increased from the “liked slightly” to the “liked moderately” grade, but the aroma attributes of sulfurous, mushroom and earthy could also be smelled in the T. melanosporum fermentation system for the first time. A total of 29 VOCs were identified, and 9 compounds were identified as the key discriminative volatiles affected by RFTT. Amino acid analysis revealed that methionine, valine, serine, phenylalanine, isoleucine and threonine were the key substrates associated with the biosynthesis of the 9 key discriminative VOCs. This study noted that amino acid metabolism played an important role in the regulation of the aroma of the T. melanosporum fermentation system. PMID:26607288

Influence of nitrogen sources on growth and fermentation performance of different wine yeast species during alcoholic fermentation.

PubMed

Kemsawasd, Varongsiri; Viana, Tiago; Ardö, Ylva; Arneborg, Nils

2015-12-01

In this study, the influence of twenty different single (i.e. 19 amino acids and ammonium sulphate) and two multiple nitrogen sources (N-sources) on growth and fermentation (i.e. glucose consumption and ethanol production) performance of Saccharomyces cerevisiae and of four wine-related non-Saccharomyces yeast species (Lachancea thermotolerans, Metschnikowia pulcherrima, Hanseniaspora uvarum and Torulaspora delbrueckii) was investigated during alcoholic fermentation. Briefly, the N-sources with beneficial effects on all performance parameters (or for the majority of them) for each yeast species were alanine, arginine, asparagine, aspartic acid, glutamine, isoleucine, ammonium sulphate, serine, valine and mixtures of 19 amino acids and of 19 amino acids plus ammonium sulphate (for S. cerevisiae), serine (for L. thermotolerans), alanine (for H. uvarum), alanine and asparagine (for M. pulcherrima), arginine, asparagine, glutamine, isoleucine and mixture of 19 amino acids (for T. delbrueckii). Furthermore, our results showed a clear positive effect of complex mixtures of N-sources on S. cerevisiae and on T. delbrueckii (although to a lesser extent) as to all performance parameters studied, whereas for L. thermotolerans, H. uvarum and M. pulcherrima, single amino acids affected growth and fermentation performance to the same extent as the mixtures. Moreover, we found groups of N-sources with similar effects on the growth and/or fermentation performance of two or more yeast species. Finally, the influences of N-sources observed for T. delbrueckii and H. uvarum resembled those of S. cerevisiae the most and the least, respectively. Overall, this work contributes to an improved understanding of how different N-sources affect growth, glucose consumption and ethanol production of wine-related yeast species under oxygen-limited conditions, which, in turn, may be used to, e.g. optimize growth and fermentation performance of the given yeast upon N-source supplementation during wine fermentations.

The Monosodium Glutamate Story: The Commercial Production of MSG and Other Amino Acids

NASA Astrophysics Data System (ADS)

Ault, Addison

2004-03-01

Examples of the industrial synthesis of pure amino acids are presented. The emphasis is on the synthesis of ( S )-glutamic acid and, to a lesser extent, ( S )-lysine and ( R,S )-methionine. These amino acids account for about 90% of the total world production of amino acids, ( S )-glutamic acid being used as a flavor-enhancing additive (MSG) for the human diet, and ( S )-lysine and ( R,S )-methionine as supplements for the feeding of domestic animals. Examples include chemical, enzymatic, and fermentation synthesis, and two clever continuous processes for the resolution of enantiomers. See Featured Molecules .

Effects of simple rain-shelter cultivation on fatty acid and amino acid accumulation in 'Chardonnay' grape berries.

PubMed

Meng, Nan; Ren, Zhi-Yuan; Yang, Xiao-Fan; Pan, Qiu-Hong

2018-02-01

Fatty acids and amino acids are the precursors of aliphatic and aromatic volatile compounds, higher alcohols and esters. They are also nutrition for yeast metabolism during fermentation. However, few reports have been concerned about the effect of viticulture practices on the accumulation of fatty acids and amino acids in wine grapes. This study aimed to explore the accumulation of these compounds in developing Vitis vinifera L. cv. Chardonnay grape berries under two vintages, and compare the influences of the rain-shelter cultivation and open-field cultivation. Fifteen fatty acids and 21 amino acids were detected in total. The rain-shelter cultivation led to an increase in the total concentration of fatty acids, and a decrease in the total concentration of amino acids compared with the open-field cultivation in 2012, while no significant difference was observed between two cultivation modes in 2013 vintage. Concentrations of palmitoleic acid, isoleucine and cysteine were significantly promoted in the rain-shelter grape berries, whereas those of tyrosine and ornithine were markedly reduced in both vintages. The rain-shelter cultivation of wine grapes in the rainy region is beneficial for improving grape quality and fermentation activity by influence on the concentration of fatty acids and amino acids. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Value-added probiotic development by high-solid fermentation of sweet potato with Saccharomyces boulardii.

PubMed

Campbell, Carmen; Nanjundaswamy, Ananda K; Njiti, Victor; Xia, Qun; Chukwuma, Franklin

2017-05-01

Controlled fermentation of Sweet potato ( Ipomoea batatas ) var. Beauregard by yeast, Saccharomyces boulardii (MAY 796) to enhance the nutritional value of sweet potato was investigated. An average 8.00 × 10 10 Colony Forming Units (CFU)/g of viable cells were obtained over 5-day high-solid fermentation. Yeast cell viability did not change significantly over time at 4°C whereas the number of viable yeast cells reduced significantly at room temperature (25°C), which was approximately 40% in 12 months. Overall, the controlled fermentation of sweet potato by MAY 796 enhanced protein, crude fiber, neutral detergent fiber, acid detergent fiber, amino acid, and fatty acid levels. Development of value-added sweet potato has a great potential in animal feed and human nutrition. S. boulardii - fermented sweet potato has great potential as probiotic-enriched animal feed and/or functional food for human nutrition.

Rapid determination of underivatized pyroglutamic acid, glutamic acid, glutamine and other relevant amino acids in fermentation media by LC-MS-MS.

PubMed

Qu, Jun; Chen, Wei; Luo, Guoan; Wang, Yiming; Xiao, Shengyuan; Ling, Zhihua; Chen, Guoqiang

2002-01-01

Determination of amino acids in a complex matrix without derivatization is advantageous, however, difficulties are found in both the detection and the separation of those compounds. In this study, a rapid and reliable LC-MS-MS method for the quantitation of underivatized amino acids in exocellular media was established. Injections were made directly after centrifugation of the samples, without further preparation. The separation of seven underivatized amino acids was achieved on a reversed-phase C18 column with pentadecafluorooctanoic acid as a volatile ion-pair reagent, and the specific detection of most amino acids was achieved by MS-MS of the specific transitions [M + H]+-->[M + H - 46]+. The calibration curves of all analytes were linear over the range of 1.0-1000 microg ml(-1) and the detection limits ranged from 0.1 to 5 ng ml(-1), with an injection volume of 20 microl. The inter-day and intra-day precisions ranged from 2.6 to 5.7% and 4.8 to 8.2%, respectively; the mean recoveries of the seven analytes were 81-104%, 91-107% and 93-101% respectively at the spiked level of 10, 40 and 200 microg ml(-1). A large number of fermentation samples were analysed using this method. The technique is simple, rapid, selective and sensitive, and shows potential for the high-throughput quantitation of amino acids from other biological matrices.

Fermentation Conditions that Affect Clavulanic Acid Production in Streptomyces clavuligerus: A Systematic Review.

PubMed

Ser, Hooi-Leng; Law, Jodi Woan-Fei; Chaiyakunapruk, Nathorn; Jacob, Sabrina Anne; Palanisamy, Uma Devi; Chan, Kok-Gan; Goh, Bey-Hing; Lee, Learn-Han

2016-01-01

The β-lactamase inhibitor, clavulanic acid is frequently used in combination with β-lactam antibiotics to treat a wide spectrum of infectious diseases. Clavulanic acid prevents drug resistance by pathogens against these β-lactam antibiotics by preventing the degradation of the β-lactam ring, thus ensuring eradication of these harmful microorganisms from the host. This systematic review provides an overview on the fermentation conditions that affect the production of clavulanic acid in the firstly described producer, Streptomyces clavuligerus. A thorough search was conducted using predefined terms in several electronic databases (PubMed, Medline, ScienceDirect, EBSCO), from database inception to June 30th 2015. Studies must involve wild-type Streptomyces clavuligerus, and full texts needed to be available. A total of 29 eligible articles were identified. Based on the literature, several factors were identified that could affect the production of clavulanic acid in S. clavuligerus. The addition of glycerol or other vegetable oils (e.g., olive oil, corn oil) could potentially affect clavulanic acid production. Furthermore, some amino acids such as arginine and ornithine, could serve as potential precursors to increase clavulanic acid yield. The comparison of different fermentation systems revealed that fed-batch fermentation yields higher amounts of clavulanic acid as compared to batch fermentation, probably due to the maintenance of substrates and constant monitoring of certain entities (such as pH, oxygen availability, etc.). Overall, these findings provide vital knowledge and insight that could assist media optimization and fermentation design for clavulanic acid production in S. clavuligerus.

Zygosaccharomyces bailii Is a Potential Producer of Various Flavor Compounds in Chinese Maotai-Flavor Liquor Fermentation

PubMed Central

Xu, Yan; Zhi, Yan; Wu, Qun; Du, Rubing; Xu, Yan

2017-01-01

Zygosaccharomyces bailii is a common yeast in various food fermentations. Understanding the metabolic properties and genetic mechanisms of Z. bailii is important for its industrial applications. Fermentation characteristics of Z. bailii MT15 from Chinese Maotai-flavor liquor fermentation were studied. Z. bailii MT15 produced various flavor compounds, including 19 alcohols, six acids, three esters, three ketones, and two aldehydes. Moreover, production of acids and aldehydes were increased by 110 and 41%, respectively, at 37°C (the maximum temperature in liquor fermentation) compared with that at 30°C, indicating its excellent flavor productivity. Z. bailii MT15 is a diploid with genome size of 20.19 Mb. Comparative transcriptome analysis revealed that 12 genes related to amino acid transport were significantly up-regulated (2.41- to 5.11-fold) at 37°C. Moreover, genes ARO8, ARO9, and ALDH4 involved in amino acid metabolism also showed higher expression levels (>1.71-fold) at 37°C. Increased substrate supply and a vigorous metabolism might be beneficial for the increased production of acids and aldehydes at 37°C. This work revealed the potential contribution of Z. bailii to various flavor compounds in food fermentation, and produced insights into the metabolic mechanisms of Z. bailii in flavor production. PMID:29312273

The impacts of temperature, alcoholic degree and amino acids content on biogenic amines and their precursor amino acids content in red wine.

PubMed

Lorenzo, C; Bordiga, M; Pérez-Álvarez, E P; Travaglia, F; Arlorio, M; Salinas, M R; Coïsson, J D; Garde-Cerdán, T

2017-09-01

The aim was to study how factors such as temperature, alcoholic degree, and amino acids supplementation are able to influence the content of tyramine, histamine, 2-phenylethylamine, tryptamine and their precursor amino acids in winemaking process. Biogenic amines and amino acids were quantified at the beginning, middle and end of alcoholic fermentation, and at the end of malolactic fermentation. In general, samples produced with amino acid supplementation did not show the highest concentrations of biogenic amines, except for histamine, which content increased with the addition of the four amino acids. The synthesis of tyramine was mainly affected by the temperature and alcoholic degree, the formation of phenylethylamine was largely influenced by alcoholic degree, and tryptamine synthesis principally depended on temperature. Interestingly, there was interaction between these three factors for the biogenic amines studied. In conclusion, winemaking conditions should be established depending on the biogenic amine which synthesis is required to be controlled. Copyright © 2017 Elsevier Ltd. All rights reserved.

Production of Bakers' Yeast in Cheese Whey Ultrafiltrate †

PubMed Central

Champagne, C. P.; Goulet, J.; Lachance, R. A.

1990-01-01

A process for the production of bakers' yeast in whey ultrafiltrate (WU) is described. Lactose in WU was converted to lactic acid and galactose by fermentation. Streptococcus thermophilus was selected for this purpose. Preculturing of S. thermophilus in skim milk considerably reduced its lag. Lactic fermentation in 2.3×-concentrated WU was delayed compared with that in unconcentrated whey, and fermentation could not be completed within 60 h. The growth rate of bakers' yeast in fermented WU differed among strains. The rate of galactose utilization was similar for all strains, but differences in lactic acid utilization occurred. Optimal pH ranges for galactose and lactic acid utilization were 5.5 to 6.0 and 5.0 to 5.5, respectively. The addition of 4 g of corn steep liquor per liter to fermented WU increased cell yields. Two sources of nitrogen were available for growth of Saccharomyces cerevisiae: amino acids (corn steep liquor) and ammonium (added during the lactic acid fermentation). Ammonium was mostly assimilated during growth on lactic acid. This process could permit the substitution of molasses by WU for the industrial production of bakers' yeast. PMID:16348117

Fermentation of Agave tequilana juice by Kloeckera africana: influence of amino-acid supplementations.

PubMed

Valle-Rodríguez, Juan Octavio; Hernández-Cortés, Guillermo; Córdova, Jesús; Estarrón-Espinosa, Mirna; Díaz-Montaño, Dulce María

2012-02-01

This study aimed to improve the fermentation efficiency of Kloeckera africana K1, in tequila fermentations. We investigated organic and inorganic nitrogen source requirements in continuous K. africana fermentations fed with Agave tequilana juice. The addition of a mixture of 20 amino-acids greatly improved the fermentation efficiency of this yeast, increasing the consumption of reducing sugars and production of ethanol, compared with fermentations supplemented with ammonium sulfate. The preference of K. africana for each of the 20 amino-acids was further determined in batch fermentations and we found that asparagine supplementation increased K. africana biomass production, reducing sugar consumption and ethanol production (by 30, 36.7 and 45%, respectively) over fermentations supplemented with ammonium sulfate. Therefore, asparagine appears to overcome K. africana nutritional limitation in Agave juice. Surprisingly, K. africana produced a high concentration of ethanol. This contrasts to poor ethanol productivities reported for other non-Saccharomyces yeasts indicating a relatively high ethanol tolerance for the K. africana K1 strain. Kloeckera spp. strains are known to synthesize a wide variety of volatile compounds and we have shown that amino-acid supplements influenced the synthesis by K. africana of important metabolites involved in the bouquet of tequila. The findings of this study have revealed important nutritional limitations of non-Saccharomyces yeasts fermenting Agave tequilana juice, and have highlighted the potential of K. africana in tequila production processes.

Microbial Successions and Metabolite Changes during Fermentation of Salted Shrimp (Saeu-Jeot) with Different Salt Concentrations

PubMed Central

Lee, Se Hee; Jung, Ji Young; Jeon, Che Ok

2014-01-01

To investigate the effects of salt concentration on saeu-jeot (salted shrimp) fermentation, four sets of saeu-jeot samples with 20%, 24%, 28%, and 32% salt concentrations were prepared, and the pH, bacterial and archaeal abundances, bacterial communities, and metabolites were monitored during the entire fermentation period. Quantitative PCR showed that Bacteria were much more abundant than Archaea in all saeu-jeot samples, suggesting that bacterial populations play more important roles than archaeal populations even in highly salted samples. Community analysis indicated that Vibrio, Photobacterium, Psychrobacter, Pseudoalteromonas, and Enterovibrio were identified as the initially dominant genera, and the bacterial successions were significantly different depending on the salt concentration. During the early fermentation period, Salinivibrio predominated in the 20% salted samples, whereas Staphylococcus, Halomonas, and Salimicrobium predominated in the 24% salted samples; eventually, Halanaerobium predominated in the 20% and 24% salted samples. The initially dominant genera gradually decreased as the fermentation progressed in the 28% and 32% salted samples, and eventually Salimicrobium became predominant in the 28% salted samples. However, the initially dominant genera still remained until the end of fermentation in the 32% salted samples. Metabolite analysis showed that the amino acid profile and the initial glycerol increase were similar in all saeu-jeot samples regardless of the salt concentration. After 30–80 days of fermentation, the levels of acetate, butyrate, and methylamines in the 20% and 24% salted samples increased with the growth of Halanaerobium, even though the amino acid concentrations steadily increased until approximately 80–107 days of fermentation. This study suggests that a range of 24–28% salt concentration in saeu-jeot fermentation is appropriate for the production of safe and tasty saeu-jeot. PMID:24587230

Effect of biogenic fermentation impurities on lactic acid hydrogenation to propylene glycol.

PubMed

Zhang, Zhigang; Jackson, James E; Miller, Dennis J

2008-09-01

The effect of residual impurities from glucose fermentation to lactic acid (LA) on subsequent ruthenium-catalyzed hydrogenation of LA to propylene glycol (PG) is examined. Whereas refined LA feed exhibits stable conversion to PG over carbon-supported ruthenium catalyst in a trickle bed reactor, partially refined LA from fermentation shows a steep decline in PG production over short (<40 h) reaction times followed by a further slow decay in performance. Addition of model impurities to refined LA has varying effects: organic acids, sugars, or inorganic salts have little effect on conversion; alanine, a model amino acid, results in a strong but reversible decline in conversion via competitive adsorption between alanine and LA on the Ru surface. The sulfur-containing amino acids cysteine and methionine irreversibly poison the catalyst for LA conversion. Addition of 0.1 wt% albumin as a model protein leads to slow decline in rate, consistent with pore plugging or combined pore plugging and poisoning of the Ru surface. This study points to the need for integrated design and operation of biological processes and chemical processes in the biorefinery in order to make efficient conversion schemes viable.

Formation of taste-active amino acids, amino acid derivatives and peptides in food fermentations - A review.

PubMed

Zhao, Cindy J; Schieber, Andreas; Gänzle, Michael G

2016-11-01

Fermented foods are valued for their rich and complex odour and taste. The metabolic activity of food-fermenting microorganisms determines food quality and generates odour and taste compounds. This communication reviews the formation of taste-active amino acids, amino acid derivatives and peptides in food fermentations. Pathways of the generation of taste compounds are presented for soy sauce, cheese, fermented meats, and bread. Proteolysis or autolysis during food fermentations generates taste-active amino acids and peptides; peptides derived from proteolysis particularly impart umami taste (e.g. α-glutamyl peptides) or bitter taste (e.g. hydrophobic peptides containing proline). Taste active peptide derivatives include pyroglutamyl peptides, γ-glutamyl peptides, and succinyl- or lactoyl amino acids. The influence of fermentation microbiota on proteolysis, and peptide hydrolysis, and the metabolism of glutamate and arginine is well understood, however, the understanding of microbial metabolic activities related to the formation of taste-active peptide derivatives is incomplete. Improved knowledge of the interactions between taste-active compounds will enable the development of novel fermentation strategies to develop tastier, less bitter, and low-salt food products, and may provide novel and "clean label" ingredients to improve the taste of other food products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Non-Saccharomyces Yeasts Nitrogen Source Preferences: Impact on Sequential Fermentation and Wine Volatile Compounds Profile.

PubMed

Gobert, Antoine; Tourdot-Maréchal, Raphaëlle; Morge, Christophe; Sparrow, Céline; Liu, Youzhong; Quintanilla-Casas, Beatriz; Vichi, Stefania; Alexandre, Hervé

2017-01-01

Nitrogen sources in the must are important for yeast metabolism, growth, and performance, and wine volatile compounds profile. Yeast assimilable nitrogen (YAN) deficiencies in grape must are one of the main causes of stuck and sluggish fermentation. The nitrogen requirement of Saccharomyces cerevisiae metabolism has been described in detail. However, the YAN preferences of non- Saccharomyces yeasts remain unknown despite their increasingly widespread use in winemaking. Furthermore, the impact of nitrogen consumption by non- Saccharomyces yeasts on YAN availability, alcoholic performance and volatile compounds production by S. cerevisiae in sequential fermentation has been little studied. With a view to improving the use of non- Saccharomyces yeasts in winemaking, we studied the use of amino acids and ammonium by three strains of non- Saccharomyces yeasts ( Starmerella bacillaris, Metschnikowia pulcherrima , and Pichia membranifaciens ) in grape juice. We first determined which nitrogen sources were preferentially used by these yeasts in pure cultures at 28 and 20°C (because few data are available). We then carried out sequential fermentations at 20°C with S. cerevisiae , to assess the impact of the non- Saccharomyces yeasts on the availability of assimilable nitrogen for S. cerevisiae . Finally, 22 volatile compounds were quantified in sequential fermentation and their levels compared with those in pure cultures of S. cerevisiae . We report here, for the first time, that non- Saccharomyces yeasts have specific amino-acid consumption profiles. Histidine, methionine, threonine, and tyrosine were not consumed by S. bacillaris , aspartic acid was assimilated very slowly by M. pulcherrima , and glutamine was not assimilated by P. membranifaciens . By contrast, cysteine appeared to be a preferred nitrogen source for all non- Saccharomyces yeasts. In sequential fermentation, these specific profiles of amino-acid consumption by non- Saccharomyces yeasts may account for some of the interactions observed here, such as poorer performances of S. cerevisiae and volatile profile changes.

Non-Saccharomyces Yeasts Nitrogen Source Preferences: Impact on Sequential Fermentation and Wine Volatile Compounds Profile

PubMed Central

Gobert, Antoine; Tourdot-Maréchal, Raphaëlle; Morge, Christophe; Sparrow, Céline; Liu, Youzhong; Quintanilla-Casas, Beatriz; Vichi, Stefania; Alexandre, Hervé

2017-01-01

Nitrogen sources in the must are important for yeast metabolism, growth, and performance, and wine volatile compounds profile. Yeast assimilable nitrogen (YAN) deficiencies in grape must are one of the main causes of stuck and sluggish fermentation. The nitrogen requirement of Saccharomyces cerevisiae metabolism has been described in detail. However, the YAN preferences of non-Saccharomyces yeasts remain unknown despite their increasingly widespread use in winemaking. Furthermore, the impact of nitrogen consumption by non-Saccharomyces yeasts on YAN availability, alcoholic performance and volatile compounds production by S. cerevisiae in sequential fermentation has been little studied. With a view to improving the use of non-Saccharomyces yeasts in winemaking, we studied the use of amino acids and ammonium by three strains of non-Saccharomyces yeasts (Starmerella bacillaris, Metschnikowia pulcherrima, and Pichia membranifaciens) in grape juice. We first determined which nitrogen sources were preferentially used by these yeasts in pure cultures at 28 and 20°C (because few data are available). We then carried out sequential fermentations at 20°C with S. cerevisiae, to assess the impact of the non-Saccharomyces yeasts on the availability of assimilable nitrogen for S. cerevisiae. Finally, 22 volatile compounds were quantified in sequential fermentation and their levels compared with those in pure cultures of S. cerevisiae. We report here, for the first time, that non-Saccharomyces yeasts have specific amino-acid consumption profiles. Histidine, methionine, threonine, and tyrosine were not consumed by S. bacillaris, aspartic acid was assimilated very slowly by M. pulcherrima, and glutamine was not assimilated by P. membranifaciens. By contrast, cysteine appeared to be a preferred nitrogen source for all non-Saccharomyces yeasts. In sequential fermentation, these specific profiles of amino-acid consumption by non-Saccharomyces yeasts may account for some of the interactions observed here, such as poorer performances of S. cerevisiae and volatile profile changes. PMID:29163451

Slight Fermentation with Lactobacillus fermentium Improves the Taste (Sugar:Acid Ratio) of Citrus (Citrus reticulata cv. chachiensis) Juice.

PubMed

Yu, Yuanshan; Xiao, Gengsheng; Xu, Yujuan; Wu, Jijun; Fu, Manqin; Wen, Jing

2015-11-01

The aim of this study was to evaluate the hypothesis that fermentation with Lactobacillus fermentium, which can metabolize citric acid, could be applied in improving the taste (sugar:acid ratio) of citrus juice. During fermentation, the strain of L. fermentium can preferentially utilize citric acid of citrus (Citrus reticulata cv. Chachiensis) juice to support the growth without the consumption of sugar. After 6 h of fermentation with L. fermentium at 30 °C, the sugar:acid ratio of citrus juice increased to 22:1 from 12:1, which resulted in that the hedonic scores of sweetness, acidity and overall acceptability of fermented-pasteurized citrus juice were higher than the unfermented-pasteurized citrus juice. Compared with unfermented-pasteurized citrus juice, the ORAC value and total amino acid showed a reduction, and no significant change (P > 0.05) in the L*, a*, b*, total soluble phenolics and ascorbic acid (Vc) content in the fermented-pasteurized citrus juice was observed as compared with unfermented-pasteurized citrus juice. Hence, slight fermentation with L. fermentium can be used for improving the taste (sugar:acid ratio) of citrus juice with the well retaining of quality. © 2015 Institute of Food Technologists®

Purification Or Organic Acids Using Anion Exchange Chromatography.

DOEpatents

Ponnampalam; Elankovan

2001-09-04

Disclosed is a cost-effective method for purifying and acidifying carboxylic acids, including organic acids and amino acids. The method involves removing impurities by allowing the anionic form of the carboxylic acid to bind to an anion exchange column and washing the column. The carboxylic anion is displaced as carboxylic acid by washing the resin with a strong inorganic anion. This method is effective in removing organic carboxylic acids and amino acids from a variety of industrial sources, including fermentation broths, hydrolysates, and waste streams.

Production of a water-soluble fertilizer containing amino acids by solid-state fermentation of soybean meal and evaluation of its efficacy on the rapeseed growth.

PubMed

Wang, Jianlei; Liu, Zhemin; Wang, Yue; Cheng, Wen; Mou, Haijin

2014-10-10

Soybean meal is a by-product of soybean oil extraction and contains approximately 44% protein. We performed solid-state fermentation by using Bacillus subtilis strain N-2 to produce a water-soluble fertilizer containing amino acids. Strain N-2 produced a high yield of protease, which transformed the proteins in soybean meal into peptide and free amino acids that were dissolved in the fermentation products. Based on the Plackett-Burman design, the initial pH of the fermentation substrate, number of days of fermentation, and the ratio of liquid to soybean meal exhibited significant effects on the recovery of proteins in the resulting water-soluble solution. According to the predicted results of the central composite design, the highest recovery of soluble proteins (99.072%) was achieved at the optimum conditions. Under these conditions, the resulting solution contained 50.42% small peptides and 7.9% poly-γ-glutamic acid (γ-PGA). The water-soluble fertilizer robustly increased the activity of the rapeseed root system, chlorophyll content, leaf area, shoot dry weight, root length, and root weight at a concentration of 0.25% (w/v). This methodology offers a value-added use of soybean meal. Copyright © 2014 Elsevier B.V. All rights reserved.

Protein digestibility-corrected amino acid scores for bean and bean-rice infant weaning food products.

PubMed

Kannan, S; Nielsen, S S; Mason, A C

2001-10-01

Vegetable proteins are an integral part of infant weaning diets in Latin America. Protein quality in plant-based products, however, is constrained by amino acid composition and intrinsically present antinutritional factors. The goal of this study was to improve bean protein quality by utilizing fermentation and germination processing. The objectives were to determine if protein quality, as measured by Food and Agricultural Organization (FAO) approved True Protein Digestibility (TPD) and Protein Digestibility-Corrected Amino Acid Scores (PDCAAS), of formulated bean-based weaning products could be improved upon fermentation and germination and if protein quality could be further improved when processed beans were combined with cooked rice. Results showed that the highest TPD and PDCAAS values were obtained for cooked germinated beans combined with rice. The TPD values for products ranged from 80 to 91%, and the PDCAAS values were 0.38-0.51. There was no significant increase (P < 0.05) of either TPD or PDCAAS values upon fermentation. Germination increased TPD of cooked bean products; this increase was not, however, accompanied by an increase in PDCAAS. When combined with rice, the PDCAAS values for all bean products improved significantly, thus supporting the concept of cereal-legume complementation. In conclusion, this study showed the range of PDCAAS in processed black bean and bean-rice infant weaning food products. The potential for incorporation of these products into the diets of weaning age Latin American children would, however, be confirmed only after validation with growth or metabolic balance studies in human infants.

Growth and Metabolism of Lactic Acid Bacteria during and after Malolactic Fermentation of Wines at Different pH

PubMed Central

Davis, C. R.; Wibowo, D. J.; Lee, T. H.; Fleet, G. H.

1986-01-01

Commercially produced red wines were adjusted to pH 3.0, 3.2, 3.5, 3.7, or 4.0 and examined during and after malolactic fermentation for growth of lactic acid bacteria and changes in the concentrations of carbohydrates, organic acids, amino acids, and acetaldehyde. With one exception, Leuconostoc oenos conducted the malolactic fermentation in all wines and was the only species to occur in wines at pH below 3.5. Malolactic fermentation by L. oenos was accompanied by degradation of malic, citric, and fumaric acids and production of lactic and acetic acids. The concentrations of arginine, histidine, and acetaldehyde also decreased at this stage, but the behavior of hexose and pentose sugars was complicated by other factors. Pediococcus parvulus conducted the malolactic fermentation in one wine containing 72 mg of total sulfur dioxide per liter. Fumaric and citric acids were not degraded during this malolactic fermentation, but hexose sugars were metabolized. P. parvulus and species of Lactobacillus grew after malolactic fermentation in wines with pH adjusted above 3.5. This growth was accompanied by the utilization of wine sugars and production of lactic and acetic acids. PMID:16347015

The Thr505 and Ser557 residues of the AGT1-encoded alpha-glucoside transporter are critical for maltotriose transport in Saccharomyces cerevisiae.

PubMed

Smit, A; Moses, S G; Pretorius, I S; Cordero Otero, R R

2008-04-01

The main objective of this study was to identify amino acid residues in the AGT1-encoded alpha-glucoside transporter (Agt1p) that are critical for efficient transport of maltotriose in the yeast Saccharomyces cerevisiae. The sequences of two AGT1-encoded alpha-glucoside transporters with different efficiencies of maltotriose transport in two Saccharomyces strains (WH310 and WH314) were compared. The sequence variations and discrepancies between these two proteins (Agt1p(WH310) and Agt1p(WH314)) were investigated for potential effects on the functionality and maltotriose transport efficiency of these two AGT1-encoded alpha-glucoside transporters. A 23-amino-acid C-terminal truncation proved not to be critical for maltotriose affinity. The identification of three amino acid differences, which potentially could have been instrumental in the transportation of maltotriose, were further investigated. Single mutations were created to restore the point mutations I505T, V549A and T557S one by one. The single site mutant V549A showed a decrease in maltotriose transport ability, and the I505T and T557S mutants showed complete reduction in maltotriose transport. The amino acids Thr(505) and Ser(557), which are respectively located in the transmembrane (TM) segment TM(11) and on the intracellular segment after TM(12) of the AGT1-encoded alpha-glucoside transporters, are critical for efficient transport of maltotriose in S. cerevisiae. Improved fermentation of starch and its dextrin products, such as maltotriose and maltose, would benefit the brewing and whisky industries. This study could facilitate the development of engineered maltotriose transporters adapted to starch-efficient fermentation systems, and offers prospects for the development of yeast strains with improved maltose and maltotriose uptake capabilities that, in turn, could increase the overall fermentation efficiencies in the beer and whisky industries.

Aromatic Amino Acid-Derived Compounds Induce Morphological Changes and Modulate the Cell Growth of Wine Yeast Species

PubMed Central

González, Beatriz; Vázquez, Jennifer; Cullen, Paul J.; Mas, Albert; Beltran, Gemma; Torija, María-Jesús

2018-01-01

Yeasts secrete a large diversity of compounds during alcoholic fermentation, which affect growth rates and developmental processes, like filamentous growth. Several compounds are produced during aromatic amino acid metabolism, including aromatic alcohols, serotonin, melatonin, and tryptamine. We evaluated the effects of these compounds on growth parameters in 16 different wine yeasts, including non-Saccharomyces wine strains, for which the effects of these compounds have not been well-defined. Serotonin, tryptamine, and tryptophol negatively influenced yeast growth, whereas phenylethanol and tyrosol specifically affected non-Saccharomyces strains. The effects of the aromatic alcohols were observed at concentrations commonly found in wines, suggesting a possible role in microbial interaction during wine fermentation. Additionally, we demonstrated that aromatic alcohols and ethanol are able to affect invasive and pseudohyphal growth in a manner dependent on nutrient availability. Some of these compounds showed strain-specific effects. These findings add to the understanding of the fermentation process and illustrate the diversity of metabolic communication that may occur among related species during metabolic processes. PMID:29696002

Nutrient assessment of olive leaf residues processed by solid-state fermentation as an innovative feedstuff additive.

PubMed

Xie, P-J; Huang, L-X; Zhang, C-H; Zhang, Y-L

2016-07-01

Olive leaf residue feedstuff additives were prepared by solid-state fermentation (SSF), and its feeding effects on broiler chickens were examined. The fermentation's nutrient value, that is, protein enrichment, cellulase activity, tannic acid degradation and amino acid enhancement, was determined. The effect of different strains, including molds (Aspergillus niger, Aspergillus oryzae and Trichoderma viride) and yeasts (Candida utilis, Candida tropicalis and Geotrichum candidum), and the fermentation time on the nutrient values of the feedstuff additives was investigated. The experimental results showed that the optimal parameters for best performance were A. niger and C. utilis in a 1 : 1 ratio (v/v) in co-culture fermentation for 5 days. Under these conditions, the total content of amino acids in the fermented olive leaf residues increased by 22·0% in comparison with that in the raw leaf residues. Both Glutamic acid and Aspartic acid contents were increased by more than 25·4%. Broiler chickens fed with different amounts of feedstuff additives were assessed. The results demonstrated that the chicken weight gains increased by 120%, and normal serum biochemical parameters were improved significantly after 10% of the feedstuff additives were supplemented to the daily chicken feed for 28 days. The co-culture combination of A. niger and C. utilis with SSF for olive leaf residue had the best nutrient values. The addition of 10% fermented olive leaf residue facilitated the chicken growth and development. This study reveals that olive leaf residues fermented by SSF exhibited considerable potential as feed additives for feeding poultry. © 2016 The Society for Applied Microbiology.

High hydrostatic pressure increases amino acid requirements in the piezo-hyperthermophilic archaeon Thermococcus barophilus.

PubMed

Cario, Anaïs; Lormières, Florence; Xiang, Xiao; Oger, Philippe

2015-11-01

We have established a defined growth medium for the piezophilic hyperthermophilic archaeon Thermococcus barophilus, which allows growth yields of ca. 10(8) cells/ml under both atmospheric and high hydrostatic pressure. Our results demonstrate a major impact of hydrostatic pressure on amino acid metabolism, with increases from 3 amino acids required at atmospheric pressure to 17 at 40 MPa. We observe in T. barophilus and other Thermococcales a similar discrepancy between the presence/absence of amino acid synthesis pathways and amino acid requirements, which supports the existence of alternate, but yet unknown, amino acid synthesis pathways, and may explain the low number of essential amino acids observed in T. barophilus and other Thermococcales. T. barophilus displays a strong metabolic preference for organic polymers such as polypeptides and chitin, which may constitute a more readily available resource of carbon and energy in situ in deep-sea hydrothermal vents. We hypothesize that the low energy yields of fermentation of organic polymers, together with energetic constraints imposed by high hydrostatic pressure, may render de novo synthesis of amino acids ecologically unfavorable. Induction of this metabolic switch to amino acid recycling can explain the requirement for non-essential amino acids by Thermococcales for efficient growth in defined medium. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Herbicide glufosinate inhibits yeast growth and extends longevity during wine fermentation.

PubMed

Vallejo, Beatriz; Picazo, Cecilia; Orozco, Helena; Matallana, Emilia; Aranda, Agustín

2017-09-29

Glufosinate ammonium (GA) is a widely used herbicide that inhibits glutamine synthetase. This inhibition leads to internal amino acid starvation which, in turn, causes the activation of different nutrient sensing pathways. GA also inhibits the enzyme of the yeast Saccharomyces cerevisiae in such a way that, although it is not used as a fungicide, it may alter yeast performance in industrial processes like winemaking. We describe herein how GA indeed inhibits the yeast growth of a wine strain during the fermentation of grape juice. In turn, GA extends longevity in a variety of growth media. The biochemical analysis indicates that GA partially inhibits the nutrient sensing TORC1 pathway, which may explain these phenotypes. The GCN2 kinase mutant is hypersensitive to GA. Hence the control of translation and amino acid biosynthesis is required to also deal with the damaging effects of this pesticide. A global metabolomics analysis under winemaking conditions indicated that an increase in amino acid and in polyamines occurred. In conclusion, GA affects many different biochemical processes during winemaking, which provides us with some insights into both the effect of this herbicide on yeast physiology and into the relevance of the metabolic step for connecting nitrogen and carbon metabolism.

Impact of phenylalanine and urea applications to Tempranillo and Monastrell vineyards on grape amino acid content during two consecutive vintages.

PubMed

Garde-Cerdán, Teresa; Gutiérrez-Gamboa, Gastón; Portu, Javier; Fernández-Fernández, José Ignacio; Gil-Muñoz, Rocío

2017-12-01

Nitrogen plays a key role in the fermentation and secondary metabolites formation. The aim was to study the influence of vine nitrogen applications on grape amino acid composition. Nitrogen sources applied to Tempranillo and Monastrell grapevines were phenylalanine and urea, during two seasons. Results showed that the application of these compounds had little effect on grape amino acid composition, regardless of variety and vintage. This could be due to the fact that vineyards did not present nitrogenous requirements. Thus, variety was the determining factor in Asp, Glu, Gln, Cit, Met, Gly, Gaba, Val, Ile, and Leu while season was the factor that most affected Thr, Arg, Ala, and Lys due its implication on berry ripening. The concentration of the remaining amino acids was influenced by two or three of the factors studied. Therefore, when the vineyard has adequate nitrogen nutritional status, grape amino acid content was determined by variety and vintage. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of amino acids in grape-derived products: a review.

PubMed

Callejón, R M; Troncoso, A M; Morales, M L

2010-06-15

The amino acids present in foods and beverages affect the quality of these products and they play an important role in enology. Amino acids are consumed by yeasts as a source of nitrogen during alcoholic fermentation and are precursors of aroma compounds. In this review various chromatographic methodologies for the determination of amino acids are described, and specific applications for the analysis of amino acid content are discussed. Amino acids usually need to be derivatized to make them more detectable. Several derivatizing reagents have been employed for the determination of amino acids in enological applications, and each has its advantages and disadvantages.

Effects of the addition of different nitrogen sources in the tequila fermentation process at high sugar concentration.

PubMed

Arrizon, J; Gschaedler, A

2007-04-01

To study the effect of the addition of different nitrogen sources at high sugar concentration in the tequila fermentation process. Fermentations were performed at high sugar concentration (170 g l(-1)) using Agave tequilana Weber blue variety with and without added nitrogen from different sources (ammonium sulfate; glutamic acid; a mixture of ammonium sulfate and amino acids) during the exponential phase of growth. All the additions increased the fermentation rate and alcohol efficiency. The level of synthesis of volatile compounds depended on the source added. The concentration of amyl alcohols and isobutanol were decreased while propanol and acetaldehyde concentration increased. The most efficient nitrogen sources for fermentation rate were ammonium sulfate and the mixture of ammonium sulfate and amino acids. The level of volatile compounds produced depended upon types of nitrogen. The synthesis of some volatile compounds increased while others decreased with nitrogen addition. The addition of nitrogen could be a strategy for improving the fermentation rate and efficiency in the tequila fermentation process at high sugar Agave tequilana concentration. Furthermore, the sensory quality of the final product may change because the synthesis of the volatile compounds is modified.

Study of the effects of proline, phenylalanine, and urea foliar application to Tempranillo vineyards on grape amino acid content. Comparison with commercial nitrogen fertilisers.

PubMed

Garde-Cerdán, T; López, R; Portu, J; González-Arenzana, L; López-Alfaro, I; Santamaría, P

2014-11-15

The aim of this work was to study the influence of foliar application of different nitrogen sources on grape amino acid content. The nitrogen sources applied to Tempranillo grapevines were proline, phenylalanine, urea, and two commercial nitrogen fertilisers, both without and with amino acids in their formulations. All treatments were applied at veraison and one week later. Proline treatment did not affect the must nitrogen composition. However, phenylalanine and urea foliar application enhanced the plants' synthesis of most of the amino acids, producing similar effects. In addition, the spray of commercial nitrogen fertilisers over leaves also induced a rise in grape amino acid concentrations regardless of the presence or absence of amino acids in their formulation. The most effective treatments were phenylalanine and urea followed by nitrogen fertilisers. This finding is of oenological interest for improved must nitrogen composition, ensuring better fermentation kinetics and most likely enhancing wine quality. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microbial production of poly-γ-glutamic acid.

PubMed

Sirisansaneeyakul, Sarote; Cao, Mingfeng; Kongklom, Nuttawut; Chuensangjun, Chaniga; Shi, Zhongping; Chisti, Yusuf

2017-09-05

Poly-γ-glutamic acid (γ-PGA) is a natural, biodegradable and water-soluble biopolymer of glutamic acid. This review is focused on nonrecombinant microbial production of γ-PGA via fermentation processes. In view of its commercial importance, the emphasis is on L-glutamic acid independent producers (i.e. microorganisms that do not require feeding with the relatively expensive amino acid L-glutamic acid to produce γ-PGA), but glutamic acid dependent production is discussed for comparison. Strategies for improving production, reducing costs and using renewable feedstocks are discussed.

Effect of processing on proximate composition, anti-nutrient status and amino acid content in three accessions of African locust bean (Parkia biglobosa (jacq.) benth.

PubMed

Urua, Ikootobong Sunday; Uyoh, Edak Aniedi; Ntui, Valentine Otang; Okpako, Elza Cletus

2013-02-01

Proximate composition, amino acid levels and anti-nutrient factors (polyphenols, phytic acid and oxalate) in the seeds of Parkia biglobosa were determined at three stages: raw, boiled and fermented. The highest anti-nutrient factor present in the raw state was oxalate, while phytic acid was the least. The amino acid of the raw seeds matched favourably to the World Health Organization reference standard. After processing, boiling increased fat, crude fibre and protein, while it reduced moisture, ash and the anti-nutrient content in 64% of the cases examined. Fermentation reduced ash, crude fibre and carbohydrate in all the accessions. It increased the moisture, fat and protein, while reducing the anti-nutrient factors in 78% of the cases. The high levels of protein, fat and amino acids coupled with the low levels of the anti-nutrients in the boiled and fermented seeds make Parkia a good source of nutrients for humans and livestock.

The effect of hexose ratios on metabolite production in Saccharomyces cerevisiae strains obtained from the spontaneous fermentation of mezcal.

PubMed

Oliva Hernández, Amanda A; Taillandier, Patricia; Reséndez Pérez, Diana; Narváez Zapata, José A; Larralde Corona, Claudia Patricia

2013-04-01

Mezcal from Tamaulipas (México) is produced by spontaneous alcoholic fermentation using Agave spp. musts, which are rich in fructose. In this study eight Saccharomyces cerevisiae isolates obtained at the final stage of fermentation from a traditional mezcal winery were analysed in three semi-synthetic media. Medium M1 had a sugar content of 100 g l(-1) and a glucose/fructose (G/F) of 9:1. Medium M2 had a sugar content of 100 g l(-1) and a G/F of 1:9. Medium M3 had a sugar content of 200 g l(-1) and a G/F of 1:1. In the three types of media tested, the highest ethanol yield was obtained from the glucophilic strain LCBG-3Y5, while strain LCBG-3Y8 was highly resistant to ethanol and the most fructophilic of the mezcal strains. Strain LCBG-3Y5 produced more glycerol (4.4 g l(-1)) and acetic acid (1 g l(-1)) in M2 than in M1 (1.7 and 0.5 g l(-1), respectively), and the ethanol yields were higher for all strains in M1 except for LCBG-3Y5, -3Y8 and the Fermichamp strain. In medium M3, only the Fermichamp strain was able to fully consume the 100 g of fructose l(-1) but left a residual 32 g of glucose l(-1). Regarding the hexose transporters, a high number of amino acid polymorphisms were found in the Hxt1p sequences. Strain LCBG-3Y8 exhibited eight unique amino acid changes, followed by the Fermichamp strain with three changes. In Hxt3p, we observed nine amino acid polymorphisms unique for the Fermichamp strain and five unique changes for the mezcal strains.

Characterization of a novel antibacterial glycopeptide produced by Penicillium sp. M03.

PubMed

Yang, W H; Zhang, W C; Lu, X M; Jiang, G S; Gao, P J

2009-04-01

To isolate a novel antibiotic termed AF from fermentation broth of Penicillium sp. M03 and to examine its antimicrobial activity, biological properties and structure characteristics. Sephadex LH-20 and HPLC were used to purify AF from fermentation broth of Penicillium sp. M03. The antimicrobial activity of AF was evaluated with the agar diffusion test. Amino acid and monosaccharide composition of AF was analysed by a HITACHI 835 detector and HPLC assay, respectively. Matrix-assisted laser desorption time of flight mass spectrometry, FT-IR and (1)H nuclear magnetic resonance spectra analyses were performed to examine the initial structure of AF. Eighty milligrams of AF was isolated as white powder from 1-l Penicillium sp. M03 fermentation broth. It consists of five amino acid and two monosaccharide residues and the molecular weight of it was 1017, and it was stable to beta-lactamase, heat, acid and alkali. AF showed inhibitory activity to a wide range of bacteria, particularly to multidrug-resistant Staphylococcus aureus. AF was a novel antibacterial glycopeptide with a broad inhibitory spectrum to pathogenic bacteria including multidrug-resistant agents. Furthermore, it is difficult to generate bacteria resistant to AF. Characterization of AF made it a potential antibiotic to fight against antibiotic-resistant bacterial pathogens.

Transcriptomes Reveal Genetic Signatures Underlying Physiological Variations Imposed by Different Fermentation Conditions in Lactobacillus plantarum

PubMed Central

Bongers, Roger S.; van Bokhorst-van de Veen, Hermien; Wiersma, Anne; Overmars, Lex; Marco, Maria L.; Kleerebezem, Michiel

2012-01-01

Lactic acid bacteria (LAB) are utilized widely for the fermentation of foods. In the current post-genomic era, tools have been developed that explore genetic diversity among LAB strains aiming to link these variations to differential phenotypes observed in the strains investigated. However, these genotype-phenotype matching approaches fail to assess the role of conserved genes in the determination of physiological characteristics of cultures by environmental conditions. This manuscript describes a complementary approach in which Lactobacillus plantarum WCFS1 was fermented under a variety of conditions that differ in temperature, pH, as well as NaCl, amino acid, and O2 levels. Samples derived from these fermentations were analyzed by full-genome transcriptomics, paralleled by the assessment of physiological characteristics, e.g., maximum growth rate, yield, and organic acid profiles. A data-storage and -mining suite designated FermDB was constructed and exploited to identify correlations between fermentation conditions and industrially relevant physiological characteristics of L. plantarum, as well as the associated transcriptome signatures. Finally, integration of the specific fermentation variables with the transcriptomes enabled the reconstruction of the gene-regulatory networks involved. The fermentation-genomics platform presented here is a valuable complementary approach to earlier described genotype-phenotype matching strategies which allows the identification of transcriptome signatures underlying physiological variations imposed by different fermentation conditions. PMID:22802930

Amino acid and fatty acid compositions of Rusip from fermented Anchovy fish (Stolephorussp)

NASA Astrophysics Data System (ADS)

Koesoemawardani, D.; Hidayati, S.; Subeki

2018-04-01

Rusip is a typical food of Bangka Belitung Indonesia made from fermented anchovy. This study aims to determine the properties of chemistry, microbiology, composition of amino acids and fatty acids from fermented fish spontaneously and non spontaneously. Spontaneous rusip treatment is done by anchovy fish (Stolephorussp) after cleaning and added salt 25% (w/w) and palm sugar 10% (w/w). While, non-spontaneous rusip is done by adding a culture mixture of Streptococcus, Leuconostoc, and Lactobacillus bacteria 2% (w/v). The materials are then incubated for 2 weeks. The data obtained were then performed t-test at the level of 5%. Spontaneous and non-spontaneous rusip fermentation process showed significant differences in total acid, reducing sugar, salt content, TVN, total lactic acid bacteria, total mold, and total microbial. The dominant amino acid content of spontaneous and non-spontaneous rusip are glutamic acid and aspartic acid, while the dominant fatty acids in spontaneous and non-spontaneous rusip are docosahexaenoic acid, palmitic acid, oleic acid, arachidonic acid, stearic acid, eicosapentaenoic acid, palmitoleic acid, and myristic acid.

Effects of temperature on microbial succession and metabolite change during saeu-jeot fermentation.

PubMed

Lee, Se Hee; Jung, Ji Young; Jeon, Che Ok

2014-04-01

To investigate the effects of temperature on saeu-jeot (shrimp) fermentation, four sets of saeu-jeot samples with approximately 25% (w/v) NaCl were fermented at 10 °C, 15 °C, 20 °C, and 25 °C. The pH values of the 10 °C and 15 °C samples were relatively constant during the entire fermentation period, whereas those of the 20 °C and 25 °C samples gradually decreased after 25 days of fermentation. Quantitative PCR showed that the maximum bacterial abundance was greater in higher temperature samples, and the bacterial abundance in the 10 °C samples steadily decreased during the entire fermentation period. Community analysis using pyrosequencing revealed that the initially dominant Proteobacteria including Pseudoalteromonas, Photobacterium, Vibrio, Aliivibrio, and Enterovibrio were replaced rapidly with Firmicutes such as Psychrobacter, Staphylococcus, Salimicrobium, Alkalibacillus, and Halanaerobium as the fermentation progressed. However, Vibrio, Photobacterium, Aliivibrio, and Enterovibrio, which may include potentially pathogenic strains, remained even after 215 days in the 10 °C samples. Metabolite analysis using (1)H NMR showed that amino acid profiles and initial quick increases of glucose and glycerol were similar and independent of bacterial growth in all temperature samples. After 25 days of fermentation, the levels of glucose, glycerol, and trimethylamine N-oxide decreased with the growth of Halanaerobium and the increase of acetate, butyrate, and methylamines in the 20 °C and 25 °C samples although the amino acid concentrations steadily increased until approximately 105 days of fermentation. Statistical triplot analysis showed that the bacterial successions occurred similarly regardless of the fermentation temperature, and Halanaerobium was likely responsible for the production of acetate, butyrate, and methylamines. This study suggests that around 15 °C might be the optimum temperature for the production of safe and tasty saeu-jeot. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of aspartic acid and glutamate on metabolism and acid stress resistance of Acetobacter pasteurianus.

PubMed

Yin, Haisong; Zhang, Renkuan; Xia, Menglei; Bai, Xiaolei; Mou, Jun; Zheng, Yu; Wang, Min

2017-06-15

Acetic acid bacteria (AAB) are widely applied in food, bioengineering and medicine fields. However, the acid stress at low pH conditions limits acetic acid fermentation efficiency and high concentration of vinegar production with AAB. Therefore, how to enhance resistance ability of the AAB remains as the major challenge. Amino acids play an important role in cell growth and cell survival under severe environment. However, until now the effects of amino acids on acetic fermentation and acid stress resistance of AAB have not been fully studied. In the present work the effects of amino acids on metabolism and acid stress resistance of Acetobacter pasteurianus were investigated. Cell growth, culturable cell counts, acetic acid production, acetic acid production rate and specific production rate of acetic acid of A. pasteurianus revealed an increase of 1.04, 5.43, 1.45, 3.30 and 0.79-folds by adding aspartic acid (Asp), and cell growth, culturable cell counts, acetic acid production and acetic acid production rate revealed an increase of 0.51, 0.72, 0.60 and 0.94-folds by adding glutamate (Glu), respectively. For a fully understanding of the biological mechanism, proteomic technology was carried out. The results showed that the strengthening mechanism mainly came from the following four aspects: (1) Enhancing the generation of pentose phosphates and NADPH for the synthesis of nucleic acid, fatty acids and glutathione (GSH) throughout pentose phosphate pathway. And GSH could protect bacteria from low pH, halide, oxidative stress and osmotic stress by maintaining the viability of cells through intracellular redox equilibrium; (2) Reinforcing deamination of amino acids to increase intracellular ammonia concentration to maintain stability of intracellular pH; (3) Enhancing nucleic acid synthesis and reparation of impaired DNA caused by acid stress damage; (4) Promoting unsaturated fatty acids synthesis and lipid transport, which resulted in the improvement of cytomembrane fluidity, stability and integrity. The present work is the study to show the effectiveness of Asp and Glu on metabolism and acid stress resistance of A. pasteurianus as well as their working mechanism. The research results will be helpful for development of nutrient salts, the optimization and regulation of high concentration of cider vinegar production process.

An OmpA family protein, a target of the GinI/GinR quorum-sensing system in Gluconacetobacter intermedius, controls acetic acid fermentation.

PubMed

Iida, Aya; Ohnishi, Yasuo; Horinouchi, Sueharu

2008-07-01

Via N-acylhomoserine lactones, the GinI/GinR quorum-sensing system in Gluconacetobacter intermedius NCI1051, a gram-negative acetic acid bacterium, represses acetic acid and gluconic acid fermentation. Two-dimensional polyacrylamide gel electrophoretic analysis of protein profiles of strain NCI1051 and ginI and ginR mutants identified a protein that was produced in response to the GinI/GinR regulatory system. Cloning and nucleotide sequencing of the gene encoding this protein revealed that it encoded an OmpA family protein, named GmpA. gmpA was a member of the gene cluster containing three adjacent homologous genes, gmpA to gmpC, the organization of which appeared to be unique to vinegar producers, including "Gluconacetobacter polyoxogenes." In addition, GmpA was unique among the OmpA family proteins in that its N-terminal membrane domain forming eight antiparallel transmembrane beta-strands contained an extra sequence in one of the surface-exposed loops. Transcriptional analysis showed that only gmpA of the three adjacent gmp genes was activated by the GinI/GinR quorum-sensing system. However, gmpA was not controlled directly by GinR but was controlled by an 89-amino-acid protein, GinA, a target of this quorum-sensing system. A gmpA mutant grew more rapidly in the presence of 2% (vol/vol) ethanol and accumulated acetic acid and gluconic acid in greater final yields than strain NCI1051. Thus, GmpA plays a role in repressing oxidative fermentation, including acetic acid fermentation, which is unique to acetic acid bacteria and allows ATP synthesis via ethanol oxidation. Consistent with the involvement of gmpA in oxidative fermentation, its transcription was also enhanced by ethanol and acetic acid.

Properties of Acetate Kinase Isozymes and a Branched-Chain Fatty Acid Kinase from a Spirochete

PubMed Central

Harwood, Caroline S.; Canale-Parola, Ercole

1982-01-01

Spirochete MA-2, which is anaerobic, ferments glucose, forming acetate as a major product. The spirochete also ferments (but does not utilize as growth substrates) small amounts of l-leucine, l-isoleucine, and l-valine, forming the branched-chain fatty acids isovalerate, 2-methylbutyrate, and isobutyrate, respectively, as end products. Energy generated through the fermentation of these amino acids is utilized to prolong cell survival under conditions of growth substrate starvation. A branched-chain fatty acid kinase and two acetate kinase isozymes were resolved from spirochete MA-2 cell extracts. Kinase activity was followed by measuring the formation of acyl phosphate from fatty acid and ATP. The branched-chain fatty acid kinase was active with isobutyrate, 2-methylbutyrate, isovalerate, butyrate, valerate, or propionate as a substrate but not with acetate as a substrate. The acetate kinase isozymes were active with acetate and propionate as substrates but not with longer-chain fatty acids as substrates. The acetate kinase isozymes and the branched-chain fatty acid kinase differed in nucleoside triphosphate and cation specificities. Each acetate kinase isozyme had an apparent molecular weight of approximately 125,000, whereas the branched-chain fatty acid kinase had a molecular weight of approximately 76,000. These results show that spirochete MA-2 synthesizes a branched-chain fatty acid kinase specific for leucine, isoleucine, and valine fermentation. It is likely that a phosphate branched-chain amino acids is also synthesized by spirochete MA-2. Thus, in spirochete MA-2, physiological mechanisms have evolved which serve specifically to generate maintenance energy from branched-chain amino acids. PMID:6288660

Production of gaba (γ – Aminobutyric acid) by microorganisms: a review

PubMed Central

Dhakal, Radhika; Bajpai, Vivek K.; Baek, Kwang-Hyun

2012-01-01

GABA (γ-aminobutyric acid) is a four carbon non-protein amino acid that is widely distributed in plants, animals and microorganisms. As a metabolic product of plants and microorganisms produced by the decarboxylation of glutamic acid, GABA functions as an inhibitory neurotransmitter in the brain that directly affects the personality and the stress management. A wide range of traditional foods produced by microbial fermentation contain GABA, in which GABA is safe and eco-friendly, and also has the possibility of providing new health-benefited products enriched with GABA. Synthesis of GABA is catalyzed by glutamate decarboxylase, therefore, the optimal fermentation condition is mainly based on the biochemical properties of the enzyme. Major GABA producing microorganisms are lactic acid bacteria (LAB), which make food spoilage pathogens unable to grow and act as probiotics in the gastrointestinal tract. The major factors affecting the production of GABA by microbial fermentation are temperature, pH, fermentation time and different media additives, therefore, these factors are summarized to provide the most up-dated information for effective GABA synthesis. There has been a huge accumulation of knowledge on GABA application for human health accompanying with a demand on natural GABA supply. Only the GABA production by microorganisms can fulfill the demand with GABA-enriched health beneficial foods. PMID:24031948

Fermentation of Xylose Causes Inefficient Metabolic State Due to Carbon/Energy Starvation and Reduced Glycolytic Flux in Recombinant Industrial Saccharomyces cerevisiae

PubMed Central

Matsushika, Akinori; Nagashima, Atsushi; Goshima, Tetsuya; Hoshino, Tamotsu

2013-01-01

In the present study, comprehensive, quantitative metabolome analysis was carried out on the recombinant glucose/xylose-cofermenting S. cerevisiae strain MA-R4 during fermentation with different carbon sources, including glucose, xylose, or glucose/xylose mixtures. Capillary electrophoresis time-of-flight mass spectrometry was used to determine the intracellular pools of metabolites from the central carbon pathways, energy metabolism pathways, and the levels of twenty amino acids. When xylose instead of glucose was metabolized by MA-R4, glycolytic metabolites including 3- phosphoglycerate, 2- phosphoglycerate, phosphoenolpyruvate, and pyruvate were dramatically reduced, while conversely, most pentose phosphate pathway metabolites such as sedoheptulose 7- phosphate and ribulose 5-phosphate were greatly increased. These results suggest that the low metabolic activity of glycolysis and the pool of pentose phosphate pathway intermediates are potential limiting factors in xylose utilization. It was further demonstrated that during xylose fermentation, about half of the twenty amino acids declined, and the adenylate/guanylate energy charge was impacted due to markedly decreased adenosine triphosphate/adenosine monophosphate and guanosine triphosphate/guanosine monophosphate ratios, implying that the fermentation of xylose leads to an inefficient metabolic state where the biosynthetic capabilities and energy balance are severely impaired. In addition, fermentation with xylose alone drastically increased the level of citrate in the tricarboxylic acid cycle and increased the aromatic amino acids tryptophan and tyrosine, strongly supporting the view that carbon starvation was induced. Interestingly, fermentation with xylose alone also increased the synthesis of the polyamine spermidine and its precursor S-adenosylmethionine. Thus, differences in carbon substrates, including glucose and xylose in the fermentation medium, strongly influenced the dynamic metabolism of MA-R4. These results provide a metabolic explanation for the low ethanol productivity on xylose compared to glucose. PMID:23874849

Fermentation and Characterization of Pitaya Wine

NASA Astrophysics Data System (ADS)

Gong, Xiao; Yang, Yaxuan; Ma, Lina; Peng, Shaodan; Lin, Mao

2017-12-01

Juice was extracted from pitaya pulp. After fermentation, the wine produced contained 11.2% vol (v/v) alcohol, total sugar content is 7.3g/L, 7.8% °Brix, the content of titratable acid and amino acid nitrogen are 2.34 g/L and 0.46 g/L, respectively. Dragon fruit wine of the communist party of detect aroma components is 56 kinds, content is more than 0.5%, 17 kinds, 9 esters are among those kinds, 5 kinds alcohol, there are 2 kinds of acids, one kind of alkanes. The physicochemical characteristics of wines produced from pitaya is attractive, with unique flavor and rich nutritional value, which makes it widely accepted and even liked.

Production of gaba (γ - Aminobutyric acid) by microorganisms: a review.

PubMed

Dhakal, Radhika; Bajpai, Vivek K; Baek, Kwang-Hyun

2012-10-01

GABA (γ-aminobutyric acid) is a four carbon non-protein amino acid that is widely distributed in plants, animals and microorganisms. As a metabolic product of plants and microorganisms produced by the decarboxylation of glutamic acid, GABA functions as an inhibitory neurotransmitter in the brain that directly affects the personality and the stress management. A wide range of traditional foods produced by microbial fermentation contain GABA, in which GABA is safe and eco-friendly, and also has the possibility of providing new health-benefited products enriched with GABA. Synthesis of GABA is catalyzed by glutamate decarboxylase, therefore, the optimal fermentation condition is mainly based on the biochemical properties of the enzyme. Major GABA producing microorganisms are lactic acid bacteria (LAB), which make food spoilage pathogens unable to grow and act as probiotics in the gastrointestinal tract. The major factors affecting the production of GABA by microbial fermentation are temperature, pH, fermentation time and different media additives, therefore, these factors are summarized to provide the most up-dated information for effective GABA synthesis. There has been a huge accumulation of knowledge on GABA application for human health accompanying with a demand on natural GABA supply. Only the GABA production by microorganisms can fulfill the demand with GABA-enriched health beneficial foods.

Effect of two doses of urea foliar application on leaves and grape nitrogen composition during two vintages.

PubMed

Pérez-Álvarez, Eva P; Garde-Cerdán, Teresa; García-Escudero, Enrique; Martínez-Vidaurre, José María

2017-06-01

Nitrogen affects grapevine growth and also yeast metabolism, which have a direct influence on fermentation kinetics and the formation of different volatile compounds. Throughout the grapevine cycle, soil nitrogen availability and grape nitrogen composition can vary because of different factors. Nitrogen foliar applications can contribute toward enhancing grapevine nitrogen status and minimize the problem of leaching that traditional nitrogen-soil applications can provoke. The present study aimed to evaluate the influence of urea foliar applications on grapevine nitrogen status and grape amino acid content. Accordingly, two different doses of urea were applied over the leaves of a 'Tempranillo' vineyard. The highest urea doses affected nitrogen content on blade leaf tissues after veraison. Must amino acid profiles were modified by urea application and some of the compounds increased their concentrations. The effect of year on the increase of must total amino acid concentrations was more important than the effect of the doses applied. Urea foliar applications can be an interesting tool for decreasing grapevine nitrogen deficiencies. This method of nitrogen implementation in the vineyard could avoid sluggish fermentation problems during winemaking, enhance must nitrogen composition, and contribute to improving wine quality. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Contribution of the microbial and meat endogenous enzymes to the free amino acid and amine contents of dry fermented sausages.

PubMed

Hierro, E; de La Hoz, L; Ordóñez, J A

1999-03-01

The role of the starter culture and meat endogenous enzymes on the free amino acid and amine contents of dry fermented sausages was studied. Five batches of sausages were prepared. The control batch was manufactured with aseptic ingredients without microbial inoculation. The other four experimental batches were manufactured with aseptic ingredients inoculated with Lactobacillus plantarum 4045 or Micrococcus-12 or L. plantarum 4045 and Micrococcus-12 or L. plantarum 4045 and Staphylococcus sp. Their effects on pH, a(w), myofibrillar proteins, and free amino acid and amine contents were studied. Sausages inoculated only with L. plantarum 4045 or with this starter combined with a Micrococcaceae had the lowest pH as a result of carbohydrate fermentation. In all batches similar patterns were observed for myofibrillar proteins and free amino acids which could indicate that meat endogenous proteases play an important role in proteolytic phenomena. No changes were observed in the amine fraction, indicating that the strains used as starter cultures did not show amino acid decarboxylase activity.

[Development of a new type of biological organic fertilizer and its effect on the growth promotion of tomato].

PubMed

Liu, Qiu Mei; Chen, Xing; Meng, Xiao Hui; Ye, Qi; Li, Tuo; Liu, Dong Yang; Shen, Qi Rong

2017-10-01

The objective of this study was to improve the ability of sporulation production of Trichoderma guizhouense NJAU4742 under solid state fermentation by using rice straw and amino acids as resources, and the fermentation products were used as inoculants of the organic fertilizers adding with different ratios of amino acids solution to develop a new type of biological organic fertilizer. The results indicated that the optimal condition for sporulation by T. guizhouense NJAU4742 was soaking in 30 times diluted amino acid solution for one whole night, with initial pH 3.5, 75% of moisture content and 30% of corn powder, under which the sporulation reached to 2.40×10 10 CFU·g -1 . The fermentation products were inoculated at 2% into the mature organic fertilizer containing 20% of amino acids solution, and the sporulation and IAA content were 6.40×10 9 CFU·g -1 and 38.66 mg·kg -1 , which were 1142.30 and 1.42 times higher than that of CK after 7 days, respectively. Pot experiment showed that biological organic fertilizer could significantly promote the growth of tomato, and the height of the tomato increased by 98.8% and 23.8%, respectively, compared with CK. The stem diameters of AT (amino acids + mature organic fertilizer + T. guizhouense NJAU4742) and AA (amino acids + mature organic fertilizer) were increased by 58.9% and 10.3%, respectively, compared with CK. As for the chlorophyll, leaf length and leaf width, the values also increased significantly. The highest spore content was obtained by using amino acids and rice straw as substrates under solid state fermentation (SSF), which overcame the difficulties of producing new type of biological organic fertilizer during the large scale industrial production. Biological organic fertilizer and amino acids organic fertilizer could significantly promote the growth of tomato compared with the chemical fertilizer, and had a good application prospect in intensive agriculture.

A single membrane-bound enzyme catalyzes the conversion of 2,5-diketo-d-gluconate to 4-keto-d-arabonate in d-glucose oxidative fermentation by Gluconobacter oxydans NBRC 3292.

PubMed

Tazoe, Masaaki; Oishi, Hiromi; Kobayashi, Setsuko; Hoshino, Tatsuo

2016-08-01

4-Keto-d-arabonate synthase (4KAS), which converts 2,5-diketo-d-gluconate (DKGA) to 4-keto-d-arabonate (4KA) in d-glucose oxidative fermentation by some acetic acid bacteria, was solubilized from the Gluconobacter oxydans NBRC 3292 cytoplasmic membrane, and purified in an electrophoretically homogenous state. A single membrane-bound enzyme was found to catalyze the conversion from DKGA to 4KA. The 92-kDa 4KAS was a homodimeric protein not requiring O2 or a cofactor for the conversion, but was stimulated by Mn(2+). N-terminal amino acid sequencing of 4KAS, followed by gene homology search indicated a 1,197-bp open reading frame (ORF), corresponding to the GLS_c04240 locus, GenBank accession No. CP004373, encoding a 398-amino acid protein with a calculated molecular weight of 42,818 Da. An Escherichia coli transformant with the 4kas plasmid exhibited 4KAS activity. Furthermore, overexpressed recombinant 4KAS was purified in an electrophoretically homogenous state and had the same molecular size as the natural enzyme.

Improvement of Nitrogen Assimilation and Fermentation Kinetics under Enological Conditions by Derepression of Alternative Nitrogen-Assimilatory Pathways in an Industrial Saccharomyces cerevisiae Strain

PubMed Central

Salmon, Jean-Michel; Barre, Pierre

1998-01-01

Metabolism of nitrogen compounds by yeasts affects the efficiency of wine fermentation. Ammonium ions, normally present in grape musts, reduce catabolic enzyme levels and transport activities for nonpreferred nitrogen sources. This nitrogen catabolite repression severely impairs the utilization of proline and arginine, both common nitrogen sources in grape juice that require the proline utilization pathway for their assimilation. We attempted to improve fermentation performance by genetic alteration of the regulation of nitrogen-assimilatory pathways in Saccharomyces cerevisiae. One mutant carrying a recessive allele of ure2 was isolated from an industrial S. cerevisiae strain. This mutation strongly deregulated the proline utilization pathway. Fermentation kinetics of this mutant were studied under enological conditions on simulated standard grape juices with various nitrogen levels. Mutant strains produced more biomass and exhibited a higher maximum CO2 production rate than the wild type. These differences were primarily due to the derepression of amino acid utilization pathways. When low amounts of dissolved oxygen were added, the mutants could assimilate proline. Biomass yield and fermentation rate were consequently increased, and the duration of the fermentation was substantially shortened. S. cerevisiae strains lacking URE2 function could improve alcoholic fermentation of natural media where proline and other poorly assimilated amino acids are the major potential nitrogen source, as is the case for most fruit juices and grape musts. PMID:9758807

Physiological analysis of yeast cells by flow cytometry during serial-repitching of low-malt beer fermentation.

PubMed

Kobayashi, Michiko; Shimizu, Hiroshi; Shioya, Suteaki

2007-05-01

At the end of beer brewing fermentation, yeast cells are collected and repitched for economical reasons. Although it is generally accepted that the physiological state of inoculated yeast cells affects their subsequent fermentation performance, the effect of serial-repitching on the physiological state of such yeast cells has not been well clarified. In this study, the fermentation performance of yeast cells during serial-repitching was investigated. After multiple repitchings, the specific growth rate and maximum optical density (OD(660)) decreased, and increases in isoamyl alcohol, which causes an undesirable flavor, and residual free amino acid nitrogen (FAN) concentrations were observed. The physiological state of individual cells before inoculation was characterized by flow cytometry using the fluorescent dyes dehydrorhodamine 123 (DHR) and bis-(1,3-dibutylbarbituric acid) trimethine oxonol (OXN). The fluorescence intensities of DHR, an indicator of reactive oxygen species (ROSs), and OXN, which indicates membrane potential, gradually increased as the number of serial-repitching cycles increased. Fluorescence intensity correlated strongly with cell growth. The subsequent fermentation performance can be predicted from this correlation.

Time course effects of fermentation on fatty acid and volatile compound profiles of Cheonggukjang using new soybean cultivars.

PubMed

Cho, Kye Man; Lim, Ho-Jeong; Kim, Mi-So; Kim, Da Som; Hwang, Chung Eun; Nam, Sang Hae; Joo, Ok Soo; Lee, Byong Won; Kim, Jae Kyeom; Shin, Eui-Cheol

2017-07-01

In this study, we investigated the effects of the potential probiotic Bacillus subtilis CSY191 on the fatty acid profiles of Cheonggukjang, a fermented soybean paste, prepared using new Korean brown soybean cultivars, protein-rich cultivar (Saedanbaek), and oil-rich cultivar (Neulchan). Twelve fatty acids were identified in the sample set-myristic, palmitic, palmitoleic, stearic, oleic, vaccenic, linoleic, α-linolenic, arachidic, gondoic, behenic, and lignoceric acids-yet, no specific changes driven by fermentation were noted in the fatty acid profiles. To further explore the effects of fermentation of B. subtilis CSY191, complete profiles of volatiles were monitored. In total, 121, 136, and 127 volatile compounds were detected in the Saedanbaek, Daewon (control cultivar), and Neulchan samples, respectively. Interestingly, the content of pyrazines-compounds responsible for pungent and unpleasant Cheonggukjang flavors-was significantly higher in Neulchan compared to that in Saedanbaek. Although the fermentation period was not a strong factor affecting the observed changes in fatty acid profiles, we noted that profiles of volatiles in Cheonggukjang changed significantly over time, and different cultivars represented specific volatile profiles. Thus, further sensory evaluation might be needed to determine if such differences influence consumers' preferences. Furthermore, additional studies to elucidate the associations between B. subtilis CSY191 fermentation and other nutritional components (e.g., amino acids) and their health-promoting potential are warranted. Copyright © 2016. Published by Elsevier B.V.

Metabolomic and proteomic analysis of D-lactate-producing Lactobacillus delbrueckii under various fermentation conditions.

PubMed

Liang, Shaoxiong; Gao, Dacheng; Liu, Huanhuan; Wang, Cheng; Wen, Jianping

2018-05-28

As an important feedstock monomer for the production of biodegradable stereo-complex poly-lactic acid polymer, D-lactate has attracted much attention. To improve D-lactate production by microorganisms such as Lactobacillus delbrueckii, various fermentation conditions were performed, such as the employment of anaerobic fermentation, the utilization of more suitable neutralizing agents, and exploitation of alternative nitrogen sources. The highest D-lactate titer could reach 133 g/L under the optimally combined fermentation condition, increased by 70.5% compared with the control. To decipher the potential mechanisms of D-lactate overproduction, the time-series response of intracellular metabolism to different fermentation conditions was investigated by GC-MS and LC-MS/MS-based metabolomic analysis. Then the metabolomic datasets were subjected to weighted correlation network analysis (WGCNA), and nine distinct metabolic modules and eight hub metabolites were identified to be specifically associated with D-lactate production. Moreover, a quantitative iTRAQ-LC-MS/MS proteomic approach was employed to further analyze the change of intracellular metabolism under the combined fermentation condition, identifying 97 up-regulated and 42 down-regulated proteins compared with the control. The in-depth analysis elucidated how the key factors exerted influence on D-lactate biosynthesis. The results revealed that glycolysis and pentose phosphate pathways, transport of glucose, amino acids and peptides, amino acid metabolism, peptide hydrolysis, synthesis of nucleotides and proteins, and cell division were all strengthened, while ATP consumption for exporting proton, cell damage, metabolic burden caused by stress response, and bypass of pyruvate were decreased under the combined condition. These might be the main reasons for significantly improved D-lactate production. These findings provide the first omics view of cell growth and D-lactate overproduction in L. delbrueckii, which can be a theoretical basis for further improving the production of D-lactate.

Study of the effect of vintage, maturity degree, and irrigation on the amino acid and biogenic amine content of a white wine from the Verdejo variety.

PubMed

Ortega-Heras, Miriam; Pérez-Magariño, Silvia; Del-Villar-Garrachón, Vanesa; González-Huerta, Carlos; Moro Gonzalez, Luis Carlos; Guadarrama Rodríguez, Alberto; Villanueva Sanchez, Sonia; Gallo González, Rubén; Martín de la Helguera, Sara

2014-08-01

The aim of this study was to determine the effect of three factors directly related to the amino acid content of grapes and their interaction. These three factors were vintage, maturity degree and irrigation. The evolution of amino acid was also assessed during the winemaking along with the effect of maturity and irrigation on the biogenic amine formation. The grapes used for this study were of the Verdejo variety. The results indicated that there was a strong vintage effect on amino acid content in grapes, which seemed to be clearly related to climatic conditions. The effect of maturity on amino acid content depended on vintage, irrigation and the amino acid itself although it was observed that irrigation caused the increase of most amino acids present in the berry. Irrigation did not affect the evolution of nitrogen compounds during the alcoholic fermentation process but the maturity degree in some of the amino acids tested did so. No direct relationship could be established between irrigation or maturity degree and biogenic amines. However, it should be noted that the biogenic amine content was very low. Vintage has a strong effect on the amino acid content in grapes which appears to be related to weather conditions. No direct relationship has been found between irrigation or maturity degree and biogenic amines content. Furthermore, it is noted that biogenic amine content found in final wines was very low. © 2013 Society of Chemical Industry.

Influence of the yeast strain on the changes of the amino acids, peptides and proteins during sparkling wine production by the traditional method.

PubMed

Martínez-Rodríguez, A J; Carrascosa, A V; Martín-Alvarez, P J; Moreno-Arribas, V; Polo, M C

2002-12-01

The influence of five yeast strains on the nitrogen fractions, amino acids, peptides and proteins, during 12 months of aging of sparkling wines produced by the traditional or Champenoise method, was studied. High-performance liquid chromatography (HPLC) techniques were used for analysis of the amino acid and peptide fractions. Proteins plus polypeptides were determined by the colorimetric Bradford method. Four main stages were detected in the aging of wines with yeast. In the first stage, a second fermentation took place; amino acids and proteins plus polypeptides diminished, and peptides were liberated. In the second stage, there was a release of amino acids and proteins, and peptides were degraded. In the third stage, the release of proteins and peptides predominated. In the fourth stage, the amino acid concentration diminished. The yeast strain used influenced the content of free amino acids and peptides and the aging time in all the nitrogen fractions.

Updates on industrial production of amino acids using Corynebacterium glutamicum.

PubMed

Wendisch, Volker F; Jorge, João M P; Pérez-García, Fernando; Sgobba, Elvira

2016-06-01

L-Amino acids find various applications in biotechnology. L-Glutamic acid and its salts are used as flavor enhancers. Other L-amino acids are used as food or feed additives, in parenteral nutrition or as building blocks for the chemical and pharmaceutical industries. L-amino acids are synthesized from precursors of central carbon metabolism. Based on the knowledge of the biochemical pathways microbial fermentation processes of food, feed and pharma amino acids have been developed. Production strains of Corynebacterium glutamicum, which has been used safely for more than 50 years in food biotechnology, and Escherichia coli are constantly improved using metabolic engineering approaches. Research towards new processes is ongoing. Fermentative production of L-amino acids in the million-ton-scale has shaped modern biotechnology and its markets continue to grow steadily. This review focusses on recent achievements in strain development for amino acid production including the use of CRISPRi/dCas9, genome-reduced strains, biosensors and synthetic pathways to enable utilization of alternative carbon sources.

Adaptive mutation of Acetobacter pasteurianus SKU1108 enhances acetic acid fermentation ability at high temperature.

PubMed

Matsutani, Minenosuke; Nishikura, Mitsuteru; Saichana, Natsaran; Hatano, Tomoyuki; Masud-Tippayasak, Uraiwan; Theergool, Gunjana; Yakushi, Toshiharu; Matsushita, Kazunobu

2013-05-20

In vitro adaptation is one of the most challenging subjects in biology to understand adaptive evolution. Microbial adaptation to temperature is not only interesting in terms of understanding the adaptation mechanism, but also useful for industrial applications. In this study, we attempted the in vitro adaptation of Acetobacter pasteurianus SKU1108 by repeating its cultivation under high-temperature acetic acid fermentation conditions. As a result, thermo-adapted strains having the higher fermentation ability than the wild-type strain were obtained. Mutations and/or disruptions in several proteins of the adapted strains were detected with NGS sequencing technology. In particular, two different adapted strains had mutations or disruptions in three specific genes in common, suggesting that these genes are essential for thermotolerance or fermentation at higher temperature. In order to clarify their involvement in thermotolerance, two of the three genes were disrupted and their phenotype was examined. The results showed that mutations of the two proteins, MarR and an amino acid transporter, are partly responsible for higher fermentation ability and/or thermotolerance. Thus, it was suggested that these elevated abilities of the adapted strains are acquired by assembling several single gene mutations including the above two mutations. Copyright © 2013 Elsevier B.V. All rights reserved.

Inoculum size-dependent interactive regulation of metabolism and stress response of Saccharomyces cerevisiae revealed by comparative metabolomics.

PubMed

Ding, Ming-Zhu; Tian, Hong-Chi; Cheng, Jing-Sheng; Yuan, Ying-Jin

2009-12-01

To investigate the metabolic regulation against inoculum density and stress response to high cell density, comparative metabolomic analysis was employed on Saccharomyces cerevisiae under fermentations with five different inoculum sizes by gas chromatography time-of-flight mass spectrometry. Samples from these fermentations were clearly distinguished by principal components analysis, indicating that inoculum size had a profound effect on the metabolism of S. cerevisiae. Potential biomarkers responsible for the discrimination were identified as glycerol, phosphoric acid, succinate, glycine, isoleucine, proline, palmitoleic acid, myo-inositol and ethanolamine. It indicated that enhanced stress protectants in glycerol biosynthesis and amino acid metabolism, depressed citric acid cycle intermediates, as well as decreased metabolites relating to membrane structure and function were involved as the inoculum size of yeast increased. Furthermore, significantly higher levels of glycerol and proline in yeast cells of higher inoculum size fermentation (40 g l(-1)) revealed that they played important roles in protecting yeast from stresses in high cell density fermentation. These findings provided new insights into characterizing the metabolic regulation and stress response depending on inoculum density during ethanol fermentation.

Exploitation of Albanian wheat cultivars: characterization of the flours and lactic acid bacteria microbiota, and selection of starters for sourdough fermentation.

PubMed

Nionelli, Luana; Curri, Nertila; Curiel, José Antonio; Di Cagno, Raffaella; Pontonio, Erica; Cavoski, Ivana; Gobbetti, Marco; Rizzello, Carlo Giuseppe

2014-12-01

Six Albanian soft and durum wheat cultivars were characterized based on chemical and technological features, showing different attitudes for bread making. Gliadin and glutenin fractions were selectively extracted from flours, and subjected to two-dimensional electrophoresis. Linja 7 and LVS flours showed the best characteristics, and abundance of high molecular weight (HMW)-glutenins. Type I sourdoughs were prepared through back slopping procedure, and the lactic acid bacteria were typed and identified. Lactobacillus plantarum and Leuconostoc mesenteroides were the predominant species. Thirty-eight representative isolates were singly used for sourdough fermentation of soft and durum wheat Albanian flours and their selection was carried out based on growth and acidification, quotient of fermentation, and proteolytic activity. Two different pools of lactic acid bacteria were designed to ferment soft or durum wheat flours. Sourdough fermentation with mixed and selected starters positively affected the quotient of fermentation, concentration of free amino acids, profile of phenolic acids, and antioxidant and phytase activities. This study provided the basis to exploit the potential of wheat Albanian flours based on an integrated approach, which considered the characterization of the flours and the processing conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Characterization of Clostridium thermocellum strains with disrupted fermentation end product pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Der Veen, Douwe; Lo, Jonathan; Brown, Steven D

2013-01-01

Clostridium thermocellum is a thermophilic, cellulolytic anaerobe that is a candidate microorganism for industrial biofuels production. Strains with mutations in genes associated with production of Llactate ( ldh) and/or acetate ( pta) were characterized to gain insight into the intracellular processes that convert cellobiose to ethanol and other fermentation end products. Cellobiose-grown cultures of the ldh strain had identical biomass accumulation, fermentation end products, transcription profile and intracellular metabolite concentrations compared to its parent strain (DSM1313 hpt spo0A). The pta-deficient strain grew slower and had 30% lower final biomass concentration compared to the parent strain, yet produced 75% more ethanol.more » A ldh pta double mutant strain evolved for faster growth had growth rate and ethanol yield comparable to the parent strain, whereas its biomass accumulation was comparable to pta. Free amino acids were secreted by all examined strains, with both pta strains secreting higher amounts of alanine, valine, isoleucine, proline, glutamine, and threonine. Valine concentration for ldh pta reached 5 mM by the end of growth, or 2.7% of the substrate carbon utilized. These secreted amino acid concentrations correlate with increased intracellular pyruvate concentrations, up to 6-fold in the pta and 16-fold in the ldh pta strain. We hypothesize that the deletions in fermentation end product pathways result in an intracellular redox imbalance, which the organism attempts to relieve, in part by recycling NADP+ through increased production of amino acids.« less

Distinctive microbiomes and metabolites linked with weight loss after gastric bypass, but not gastric banding.

PubMed

Ilhan, Zehra Esra; DiBaise, John K; Isern, Nancy G; Hoyt, David W; Marcus, Andrew K; Kang, Dae-Wook; Crowell, Michael D; Rittmann, Bruce E; Krajmalnik-Brown, Rosa

2017-09-01

Roux-en-Y gastric bypass (RYGB) and laparoscopic adjustable gastric banding (LAGB) are anatomically different bariatric operations. RYGB achieves greater weight loss compared with LAGB. Changes in the gut microbiome have been documented after RYGB, but not LAGB, and the microbial contribution to sustainable surgical weight loss warrants further evaluation. We hypothesized that RYGB imposes greater changes on the microbiota and its metabolism than LAGB, and that the altered microbiota may contribute to greater weight loss. Using multi-omic approaches, we analyzed fecal microbial community structure and metabolites of pre-bariatric surgery morbidly obese (PreB-Ob), normal weight (NW), post-RYGB, and post-LAGB participants. RYGB microbiomes were significantly different from those from NW, LAGB and PreB-Ob. Microbiome differences between RYGB and PreB-Ob populations were mirrored in their metabolomes. Diversity was higher in RYGB compared with LAGB, possibly because of an increase in the abundance of facultative anaerobic, bile-tolerant and acid-sensible microorganisms in the former. Possibly because of lower gastric acid exposure, phylotypes from the oral cavity, such as Escherichia, Veillonella and Streptococcus, were in greater abundance in the RYGB group, and their abundances positively correlated with percent excess weight loss. Many of these post-RYGB microorganisms are capable of amino-acid fermentation. Amino-acid and carbohydrate fermentation products-isovalerate, isobutyrate, butyrate and propionate-were prevalent in RYGB participants, but not in LAGB participants. RYGB resulted in greater alteration of the gut microbiome and metabolome than LAGB, and RYGB group exhibited unique microbiome composed of many amino-acid fermenters, compared with nonsurgical controls.

Impact of fermentation rate changes on potential hydrogen sulfide concentrations in wine.

PubMed

Butzke, Christian E; Park, Seung Kook

2011-05-01

The correlation between alcoholic fermentation rate, measured as carbon dioxide (CO2) evolution, and the rate of hydrogen sulfide (H2S) formation during wine production was investigated. Both rates and the resulting concentration peaks in fermentor headspace H2S were directly impacted by yeast assimilable nitrogenous compounds in the grape juice. A series of model fermentations was conducted in temperature-controlled and stirred fermentors using a complex model juice with defined concentrations of ammonium ions and/or amino acids. The fermentation rate was measured indirectly by noting the weight loss of the fermentor; H2S was quantitatively trapped in realtime using a pre-calibrated H2S detection tube which was inserted into a fermentor gas relief port. Evolution rates for CO2 and H2S as well as the relative ratios between them were calculated. These fermentations confirmed that total sulfide formation was strongly yeast strain-dependent, and high concentrations of yeast assimilable nitrogen did not necessarily protect against elevated H2S formation. High initial concentrations of ammonium ions via addition of diammonium phosphate (DAP) caused a higher evolution of H2S when compared with a non-supplemented but nondeficient juice. It was observed that the excess availability of a certain yeast assimilable amino acid, arginine, could result in a more sustained CO2 production rate throughout the wine fermentation. The contribution of yeast assimilable amino acids from conventional commercial yeast foods to lowering of the H2S formation was marginal.

Chemical changes associated with lotus and water lily natto production

NASA Astrophysics Data System (ADS)

Lestari, S. D.; Fatimah, N.; Nopianti, R.

2017-04-01

Natto is a traditional Japanese food made by fermenting whole soybean seeds with pure culture of Bacillus subtilis subsp. natto. The purpose of this study was to investigate the suitability of lotus (Nelumbo nucifera) and water lily (Nymphaea stellata) seeds as the raw materials for natto production. Chemical (proximate, amino acids and minerals) changes were observed on raw, steamed and fermented seeds. Proximate compositions of all samples were calculated in both wet basis and dry basis. In wet basis calculation, steaming and fermentation tended to lower the carbohydrates, ashes, fats and protein content which were attributed to the increase of moisture. The total amino acid, iron and magnesium contents of raw lotus seeds were 24.29%, 5.08 mg 100g-1 and 174.23 mg 100g-1 dry matter, respectively. After a 24h-fermentation at 40°C, the total amino acids decreased while iron and magnesium contents increased significantly reaching, in respective order, 9.9 mg 100g-1 and 411.36 mg 100g-1 dry matter. Changes in chemical composition after fermentation were more pronounced in lotus seeds than water lily seeds indicating that their nutrient composition were more suitable to support Bacillus subtilis growth.

Distinctive microbiomes and metabolites linked with weight loss after gastric bypass, but not gastric banding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ilhan, Zehra Esra; DiBaise, John K.; Isern, Nancy G.

Roux-en-Y gastric bypass (RYGB) and laparoscopic adjustable gastric banding (LAGB) are anatomically different bariatric operations. RYGB achieves greater weight loss compared with LAGB. Changes in the gut microbiome have been documented after RYGB, but not LAGB, and the microbial contribution to sustainable surgical weight loss warrants further evaluation. We hypothesized that RYGB imposes greater changes on the microbiota and its metabolism than LAGB, and that the altered microbiota may contribute to greater weight loss. Using multi-omic approaches, we analyzed fecal microbial community structure and metabolites of pre-bariatric surgery morbidly obese (PreB-Ob), normal weight (NW), post-RYGB, and post-LAGB participants. RYGB microbiomesmore » were significantly different from those from NW, LAGB and PreB-Ob. Microbiome differences between RYGB and PreB- Ob populations were mirrored in their metabolomes. Diversity was higher in RYGB compared with LAGB, possibly because of an increase in the abundance of facultative anaerobic, bile-tolerant and acid-sensible microorganisms in the former. Possibly because of lower gastric acid exposure, phylotypes from the oral cavity, such as Escherichia, Veillonella and Streptococcus, were in greater abundance in the RYGB group, and their abundances positively correlated with percent excess weight loss. Many of these post-RYGB microorganisms are capable of amino-acid fermentation. Amino-acid and carbohydrate fermentation products—isovalerate, isobutyrate, butyrate and propionate—were prevalent in RYGB participants, but not in LAGB participants. RYGB resulted in greater alteration of the gut microbiome and metabolome than LAGB, and RYGB group exhibited unique microbiome composed of many amino-acid fermenters, compared with nonsurgical controls.« less

Insights into the Biogenic Amine Metabolic Landscape during Industrial Semidry Chinese Rice Wine Fermentation.

PubMed

Xia, Xiaole; Zhang, Qingwen; Zhang, Bin; Zhang, Wuji; Wang, Wu

2016-10-05

Inspired by concerns about food safety, the metabolic landscape of biogenic amines (BAs) was elucidated during industrial semidry Chinese rice wine fermentation. The main fermentation process represented the largest contribution to BA formation, which corresponded to 69.1% (54.3 mg/L). Principal component analysis revealed that total acid and ethanol were strongly correlated with BAs, indicating that BA formation favored acidic and stressful conditions. Other than putrescine (PUT), spermidine (SPD), and spermine (SPM), 5 BAs exhibited strong relationships with the precursor amino acids (R 2 > 0.85). PUT was mainly decarboxylated from arginine (89.6%) whereas SPD (100%) and SPM (83.1%) were obtained from ornithine. Interestingly, some SPD could convert back to PUT (24.3%). All 8 BAs showed good relationships with lactic acid bacteria (LAB) (R 2 around 0.75). Moreover, among the five main LAB genera, Lactobacillus had a positive correlation with BA formation.

L-Cysteine Metabolism and Fermentation in Microorganisms.

PubMed

Takagi, Hiroshi; Ohtsu, Iwao

L-Cysteine is an important amino acid both biologically and commercially. Although most amino acids are industrially produced by microbial fermentation, L-cysteine has been mainly produced by protein hydrolysis. Due to environmental and safety problems, synthetic or biotechnological products have been preferred in the market. Here, we reviewed L-cysteine metabolism, including biosynthesis, degradation, and transport, and biotechnological production (including both enzymatic and fermentation processes) of L-cysteine. The metabolic regulation of L-cysteine including novel sulfur metabolic pathways found in microorganisms is also discussed. Recent advancement in biochemical studies, genome sequencing, structural biology, and metabolome analysis has enabled us to use various approaches to achieve direct fermentation of L-cysteine from glucose. For example, worldwide companies began to supply L-cysteine and its derivatives produced by bacterial fermentation. These companies successfully optimized the original metabolism of their private strains. Basically, a combination of three factors should be required for improving L-cysteine fermentation: that is, (1) enhancing biosynthesis: overexpression of the altered cysE gene encoding feedback inhibition-insensitive L-serine O-acetyltransferase (SAT), (2) weakening degradation: knockout of the genes encoding L-cysteine desulfhydrases, and (3) exploiting export system: overexpression of the gene involved in L-cysteine transport. Moreover, we found that "thiosulfate" is much more effective sulfur source than commonly used "sulfate" for L-cysteine production in Escherichia coli, because thiosulfate is advantageous for saving consumption of NADPH and relating energy molecules.

An aerobic detoxification photofermentation by Rhodospirillum rubrum for converting soy sauce residue into feed with moderate pretreatment.

PubMed

Zhang, Jian; Yuan, Jie; Zhang, Wen-Xue; Zhu, Wen-You; Tu, Fang; Jiang, Ya; Sun, Chuan-Ze

2017-09-25

This paper reports an effective process for converting soy sauce residue into feeds by combining moderate acid hydrolysis and ammonization with Rhodospirillum rubrum fermentation. After pretreatment with dilute sulfuric or phosphoric acid (1%, w/w) at 100 °C, materials were subjected to fermentation under several gases (N 2 , CO 2 , and air) and different light intensities in a 2-L fermentor. Following sulfuric acid treatment, the true protein increased from 188 to 362 g kg -1 and the crude fiber decreased from 226 to 66 g kg -1 after fermentation at 0.5 L min -1  L -1 of air flow and a light intensity of 750 lx and following phosphoric acid treatment, the true protein increased by 90% and the crude fiber decreased by 67% after fermentation at 0.6 L min -1  L -1 of air flow and a light intensity of 600 lx Other contents, including crude fat, crude ash, phosphorus, sulfur, sulfur-containing amino acids, sodium chloride, and calcium, were also improved for use as feed. Meantime, some toxic substances, including furfural, hydroxymethylfurfural (5-HMF), acetic acid, phenol, and cresol, which were produced by the pretreatments, could be removed by 12-32, 5-8, 49-53, 7-8, and 7-8%, respectively; and total sugars, glucose, and xylose could be utilized by 68-69, 71-72, and 63-67% respectively. The quality of soy sauce residue is improved for use as feed and some toxic substances can be decreased via the R. rubrum fermentation.

An OmpA Family Protein, a Target of the GinI/GinR Quorum-Sensing System in Gluconacetobacter intermedius, Controls Acetic Acid Fermentation▿ †

PubMed Central

Iida, Aya; Ohnishi, Yasuo; Horinouchi, Sueharu

2008-01-01

Via N-acylhomoserine lactones, the GinI/GinR quorum-sensing system in Gluconacetobacter intermedius NCI1051, a gram-negative acetic acid bacterium, represses acetic acid and gluconic acid fermentation. Two-dimensional polyacrylamide gel electrophoretic analysis of protein profiles of strain NCI1051 and ginI and ginR mutants identified a protein that was produced in response to the GinI/GinR regulatory system. Cloning and nucleotide sequencing of the gene encoding this protein revealed that it encoded an OmpA family protein, named GmpA. gmpA was a member of the gene cluster containing three adjacent homologous genes, gmpA to gmpC, the organization of which appeared to be unique to vinegar producers, including “Gluconacetobacter polyoxogenes.” In addition, GmpA was unique among the OmpA family proteins in that its N-terminal membrane domain forming eight antiparallel transmembrane β-strands contained an extra sequence in one of the surface-exposed loops. Transcriptional analysis showed that only gmpA of the three adjacent gmp genes was activated by the GinI/GinR quorum-sensing system. However, gmpA was not controlled directly by GinR but was controlled by an 89-amino-acid protein, GinA, a target of this quorum-sensing system. A gmpA mutant grew more rapidly in the presence of 2% (vol/vol) ethanol and accumulated acetic acid and gluconic acid in greater final yields than strain NCI1051. Thus, GmpA plays a role in repressing oxidative fermentation, including acetic acid fermentation, which is unique to acetic acid bacteria and allows ATP synthesis via ethanol oxidation. Consistent with the involvement of gmpA in oxidative fermentation, its transcription was also enhanced by ethanol and acetic acid. PMID:18487322

Managing Your Wine Fermentation to Reduce the Risk of Biogenic Amine Formation

PubMed Central

Smit, Anita Yolandi; Engelbrecht, Lynn; du Toit, Maret

2012-01-01

Biogenic amines are nitrogenous organic compounds produced in wine from amino acid precursors mainly by microbial decarboxylation. The concentration of biogenic amines that can potentially be produced is dependent on the amount of amino acid precursors in the medium, the presence of decarboxylase positive microorganisms and conditions that enable microbial or biochemical activity such as the addition of nutrients to support the inoculated starter cultures for alcoholic and malolactic fermentation (MLF). MLF can be conducted using co-inoculation or an inoculation after the completion of alcoholic fermentation that may also affect the level of biogenic amines in wine. This study focused on the impact of the addition of complex commercial yeast and bacterial nutrients and the use of different MLF inoculation scenarios on the production of biogenic amines in wine. Results showed that the addition of complex nutrients to real grape must could potentially increase histamine concentrations in wine. The same experiment in synthetic grape must showed a similar trend for putrescine and cadaverine. The effect of different MLF inoculation scenarios was examined in two cultivars, Pinotage and Shiraz. Conflicting results was obtained. In the Shiraz, co-inoculation resulted in lower biogenic amine concentrations after MLF compared to before MLF, while the concentration was higher in the Pinotage. However, the production of biogenic amines was affected more by the presence of decarboxylase positive lactic acid bacteria than by the addition of complex nutrients or the inoculation scenario. PMID:22419915

Quality, antioxidative ability, and cell proliferation-enhancing activity of fermented black soybean broths with various supplemental culture medium.

PubMed

Lin, Chih-Chien; Wu, Pey-Shiuan; Liang, David Woei-Ming; Kwan, Chang-Chin; Chen, Yi-Shyan

2012-01-01

The fermented soybean-based foods have played an important role in traditional diets around the world for many centuries, and Bacillus subtilis is typically used in the fermentation of soybean-based foods. The fermentation process may improve not only the flavor but also the nutritional value of food, and substances produced in this fermented broth were affected by many factors including culture medium and the selected soybeans. In this study, we use 3 potential culture mediums in the fermentation of black soybean and the fermented black soybean broths were used for the examination of amino acid composition, total phenolics content, flavonoids and anthocyanins contents, the antioxidant properties, and cytotoxicity. Our results indicated that the fermented black soybean broth, fermentation III, have the most abundant essential amino acid (79.77 mg/g), phenolics (19.33 mg/g), flavonoids (46.01 mg/g), and anthocyanins (1.06 mg/g). Besides, all of the fermented black soybean broths exhibited the significant antioxidative abilities with 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging effect, reducing power and ferrous ion chelating effect. In addition, the fermented black soybean broths demonstrated the cell proliferation-enhancing activity in Detroit 551 cells. The cells were augmented up to the maximum value of 183.6% (compared with control) at 10 mg/mL of the fermentation I. Therefore, the different supplemental culture medium fermented black soybean broths may be used as a functional ingredient in the products of nutritional drinks and health foods. The present study illustrated the potential of various supplemental culture medium fermented black soybean broths in the application of functional ingredient for nutritional drinks and health foods. © 2011 Institute of Food Technologists®

Qualitative and quantitative prediction of volatile compounds from initial amino acid profiles in Korean rice wine (makgeolli) model.

PubMed

Kang, Bo-Sik; Lee, Jang-Eun; Park, Hyun-Jin

2014-06-01

In Korean rice wine (makgeolli) model, we tried to develop a prediction model capable of eliciting a quantitative relationship between initial amino acids in makgeolli mash and major aromatic compounds, such as fusel alcohols, their acetate esters, and ethyl esters of fatty acids, in makgeolli brewed. Mass-spectrometry-based electronic nose (MS-EN) was used to qualitatively discriminate between makgeollis made from makgeolli mashes with different amino acid compositions. Following this measurement, headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry (GC-MS) combined with partial least-squares regression (PLSR) method was employed to quantitatively correlate amino acid composition of makgeolli mash with major aromatic compounds evolved during makgeolli fermentation. In qualitative prediction with MS-EN analysis, the makgeollis were well discriminated according to the volatile compounds derived from amino acids of makgeolli mash. Twenty-seven ion fragments with mass-to-charge ratio (m/z) of 55 to 98 amu were responsible for the discrimination. In GC-MS combined with PLSR method, a quantitative approach between the initial amino acids of makgeolli mash and the fusel compounds of makgeolli demonstrated that coefficient of determination (R(2)) of most of the fusel compounds ranged from 0.77 to 0.94 in good correlation, except for 2-phenylethanol (R(2) = 0.21), whereas R(2) for ethyl esters of MCFAs including ethyl caproate, ethyl caprylate, and ethyl caprate was 0.17 to 0.40 in poor correlation. The amino acids have been known to affect the aroma in alcoholic beverages. In this study, we demonstrated that an electronic nose qualitatively differentiated Korean rice wines (makgeollis) by their volatile compounds evolved from amino acids with rapidity and reproducibility and successively, a quantitative correlation with acceptable R2 between amino acids and fusel compounds could be established via HS-SPME GC-MS combined with partial least-squares regression. Our approach for predicting the quantities of volatile compounds in the finished product from initial condition of fermentation will give an insight to food researchers to modify and optimize the qualities of the corresponding products. © 2014 Institute of Food Technologists®

Metabolic profiling of sourdough fermented wheat and rye bread.

PubMed

Koistinen, Ville M; Mattila, Outi; Katina, Kati; Poutanen, Kaisa; Aura, Anna-Marja; Hanhineva, Kati

2018-04-09

Sourdough fermentation by lactic acid bacteria is commonly used in bread baking, affecting several attributes of the final product. We analyzed whole-grain wheat and rye breads and doughs prepared with baker's yeast or a sourdough starter including Candida milleri, Lactobacillus brevis and Lactobacillus plantarum using non-targeted metabolic profiling utilizing LC-QTOF-MS. The aim was to determine the fermentation-induced changes in metabolites potentially contributing to the health-promoting properties of whole-grain wheat and rye. Overall, we identified 118 compounds with significantly increased levels in sourdough, including branched-chain amino acids (BCAAs) and their metabolites, small peptides with high proportion of BCAAs, microbial metabolites of phenolic acids and several other potentially bioactive compounds. We also identified 69 compounds with significantly decreased levels, including phenolic acid precursors, nucleosides, and nucleobases. Intensive sourdough fermentation had a higher impact on the metabolite profile of whole-grain rye compared to milder whole-grain wheat sourdough fermentation. We hypothesize that the increased amount of BCAAs and potentially bioactive small peptides may contribute to the insulin response of rye bread, and in more general, the overall protective effect against T2DM and CVD.

Reduction of biogenic amines production by eliminating the PEP4 gene in Saccharomyces cerevisiae during fermentation of Chinese rice wine.

PubMed

Guo, Xuewu; Guan, Xiangyu; Wang, Yazhou; Li, Lina; Wu, Deguang; Chen, Yefu; Pei, Huadong; Xiao, Dongguang

2015-07-01

Biogenic amines in Chinese rice wine have a potential threat of toxicity to human health. In this study, PEP4 gene in Saccharomyces cerevisiae was knocked out in order to evaluate its effect on biogenic amines production; the enzyme encodes proteinase A (PrA), an enzyme that is responsible for the production of free amino acids. It was found that compared to the wild type strain, the PrA activity and amino acid concentration decreased significantly, and the production of biogenic amines in this knockout strain decreased by 25.5%, from 180.1mg/L to 134.2mg/L. Especially, tyramine, cadaverine and histamine concentrations were also decreased by 57.5%, 24.6% and 54.3%, respectively. The main reason for the decrease of biogenic amines may be due to the low concentration of free amino acids. Our results provide a new strategy to minimize the biogenic amine production during fermentation of Chinese rice wine. Copyright © 2015 Elsevier Ltd. All rights reserved.

Economic process to co-produce poly(ε-l-lysine) and poly(l-diaminopropionic acid) by a pH and dissolved oxygen control strategy.

PubMed

Xu, Zhaoxian; Feng, Xiaohai; Sun, Zhuzhen; Cao, Changhong; Li, Sha; Xu, Zheng; Xu, Zongqi; Bo, Fangfang; Xu, Hong

2015-01-01

This study tended to apply biorefinery of indigenous microbes to the fermentation of target-product generation through a novel control strategy. A novel strategy for co-producing two valuable homopoly(amino acid)s, poly(ε-l-lysine) (ε-PL) and poly(l-diaminopropionic acid) (PDAP), was developed by controlling pH and dissolved oxygen concentrations in Streptomyces albulus PD-1 fermentation. The production of ε-PL and PDAP got 29.4 and 9.6gL(-1), respectively, via fed-batch cultivation in a 5L bioreactor. What is more, the highest production yield (21.8%) of similar production systems was achieved by using this novel strategy. To consider the economic-feasibility, large-scale production in a 1t fermentor was also implemented, which would increase the gross profit of 54,243.5USD from one fed-batch bioprocess. This type of fermentation, which produces multiple commercial products from a unified process is attractive, because it will improve the utilization rate of raw materials, enhance production value and enrich product variety. Copyright © 2015 Elsevier Ltd. All rights reserved.

Characterization of Clostridium thermocellum strains with disrupted fermentation end-product pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Der Veen, Douwe; Lo, Jonathan; Brown, Steven D

2013-01-01

Clostridium thermocellum is a thermophilic, cellulolytic anaerobe that is a candidate microorganism for industrial biofuels production. Strains with mutations in genes associated with production of L-lactate (Dldh) and/or acetate (Dpta) were characterized to gain insight into the intracellular processes that convert cellobiose to ethanol and other fermentation end-products. Cellobiose-grown cultures of the Dldh strain had identical biomass accumulation, fermentation end-products, transcription profile, and intracellular metabolite concentrations compared to its parent strain (DSM1313 Dhpt Dspo0A). The Dpta-deficient strain grew slower and had 30 % lower final biomass concentration compared to the parent strain, yet produced 75% more ethanol. A Dldh Dptamore » double-mutant strain evolved for faster growth had a growth rate and ethanol yield comparable to the parent strain, whereas its biomass accumulation was comparable to Dpta. Free amino acids were secreted by all examined strains, with both Dpta strains secreting higher amounts of alanine, valine, isoleucine, proline, glutamine, and threonine. Valine concentration for Dldh Dpta reached 5 mM by the end of growth, or 2.7 % of the substrate carbon utilized. These secreted amino acid concentrations correlate with increased intracellular pyruvate concentrations, up to sixfold in the Dpta and 16-fold in the Dldh Dpta strain. We hypothesize that the deletions in fermentation end-product pathways result in an intracellular redox imbalance, which the organism attempts to relieve, in part by recycling NADP* through increased production of amino acids.« less

Yogurt-like beverages made of a mixture of cereals, soy and grape must: microbiology, texture, nutritional and sensory properties.

PubMed

Coda, Rossana; Lanera, Alessia; Trani, Antonio; Gobbetti, Marco; Di Cagno, Raffaella

2012-04-16

Cereal (rice, barley, emmer and oat) and soy flours and concentrated red grape must were used for making vegetable yogurt-like beverages (VYLB). Two selected strains of Lactobacillus plantarum were used for lactic acid fermentation, according to a process which included the flour gelatinization. All VLYB had values of pH lower than 4.0 and both selected starters remained viable at ca. 8.4 log cfu/g throughout storage. All VLYB showed high values of apparent viscosity and water holding capacity. During fermentation, lactic acid bacteria consumed glucose, fructose, and malic acid, which was supplied with grape must. Compared to control vegetable yogurt-like beverages (CVYLB), without bacterial inoculum, an increase of total free amino acids (FAA) was found during fermentation and storage. Also the concentration of polyphenolic compounds and ascorbic acid (ASC) was higher in VLYB compared to CVYLB. This was reflected on the antioxidant activity. As determined by Solid Phase Micro-Extraction/Gas-Chromatography/Mass-Spectrometry analysis, several volatile compounds were identified. Beverages made with the mixture of rice and barley or emmer flours seemed to possess the best combination textural, nutritional and sensory properties. Copyright © 2012 Elsevier B.V. All rights reserved.

Impact of short-term intake of red wine and grape polyphenol extract on the human metabolome.

PubMed

Jacobs, Doris M; Fuhrmann, Jens C; van Dorsten, Ferdinand A; Rein, Dietrich; Peters, Sonja; van Velzen, Ewoud J J; Hollebrands, Boudewijn; Draijer, Richard; van Duynhoven, John; Garczarek, Ursula

2012-03-28

Red wine and grape polyphenols are considered to promote cardiovascular health and are involved in multiple biological functions. Their overall impact on the human metabolome is not known. Therefore, exogenous and endogenous metabolic effects were determined in fasting plasma and 24 h urine from healthy male adults consuming a mix of red wine and grape juice extracts (WGM) for 4 days in a placebo-controlled, crossover study. Syringic acid, 3-hydroxyhippuric acid, pyrogallol, 3-hydroxyphenylacetic acid, and 3-hydroxyphenylpropionic acid were confirmed as the strongest urinary markers of WGM intake. Overall, WGM had a mild impact on the endogenous metabolism. Most noticeable were changes in several amino acids deriving from tyrosine and tryptophan. Reductions in the microbial metabolites p-cresol sulfate and 3-indoxylsulfuric acid and increases in indole-3-lactic acid and nicotinic acid were observed in urine. In plasma, tyrosine was reduced. The results suggest that short-term intake of WGM altered microbial protein fermentation and/or amino acid metabolism.

Simultaneous saccharification and fermentation of broken rice: an enzymatic extrusion liquefaction pretreatment for Chinese rice wine production.

PubMed

Li, Hongyan; Jiao, Aiquan; Xu, Xueming; Wu, Chunsen; Wei, Benxi; Hu, Xiuting; Jin, Zhengyu; Tian, Yaoqi

2013-08-01

Broken rice, pretreated by enzymatic extrusion liquefaction, was used to produce Chinese rice wine by simultaneous saccharification and fermentation (SSF) process in this study. The study compared the novel process and traditional process for Chinese rice wine fermentation utilizing broken rice and head rice, respectively. With the optimum extrusion parameters (barrel temperature, 98 °C; moisture content, 42% and amylase concentration, 1‰), 18% (v/v at 20 °C) alcoholic degree, 37.66% fermentation recovery and 93.63% fermentation efficiency were achieved, indicating enzymatic extrusion-processed rice wine from broken rice exhibited much higher fermentation rate and efficiency than traditional-processed rice wine from head rice during SSF. The starch molecule distribution data indicated that the alcoholic degree was related to the oligosaccharides' formation during enzymatic extrusion. Sum of amino acid (AA) in the extrusion-processed wine was 53.7% higher than that in the traditional one. These results suggest that the enzymatic extrusion pretreatment for broken rice is a feasible and alternative process in the fermentation of Chinese rice wine.

Soluble arabinoxylan enhances large intestinal microbial health biomarkers in pigs fed a red meat-containing diet.

PubMed

Williams, Barbara A; Zhang, Dagong; Lisle, Allan T; Mikkelsen, Deirdre; McSweeney, Christopher S; Kang, Seungha; Bryden, Wayne L; Gidley, Michael J

2016-04-01

The aim of this study was to investigate how moderately increased dietary red meat combined with a soluble fiber (wheat arabinoxylan [AX]) alters the large intestinal microbiota in terms of fermentative end products and microbial community profiles in pigs. Four groups of 10 pigs were fed Western-type diets containing two amounts of red meat, with or without a solubilized wheat AX-rich fraction for 4 wk. After euthanasia, fermentative end products (short-chain fatty acids, ammonia) of digesta from four sections of large intestine were measured. Di-amino-pimelic acid was a measure of total microbial biomass, and bacterial profiles were determined using a phylogenetic microarray. A factorial model determined effects of AX and meat content. Arabinoxylan was highly fermentable in the cecum, as indicated by increased concentrations of short-chain fatty acids (particularly propionate). Protein fermentation end products were decreased, as indicated by the reduced ammonia and branched-chain ratio although this effect was less prominent distally. Microbial profiles in the distal large intestine differed in the presence of AX (including promotion of Faecalibacterium prausnitzii), consistent with an increase in carbohydrate versus protein fermentation. Increased di-amino-pimelic acid (P < 0.0001) suggested increased microbial biomass for animals fed AX. Solubilized wheat AX has the potential to counteract the effects of dietary red meat by reducing protein fermentation and its resultant toxic end products such as ammonia, as well as leading to a positive shift in fermentation end products and microbial profiles in the large intestine. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

Branched chain amino acids maintain the molecular weight of poly(γ-glutamic acid) of Bacillus licheniformis ATCC 9945 during the fermentation.

PubMed

Mitsunaga, Hitoshi; Meissner, Lena; Büchs, Jochen; Fukusaki, Eiichiro

2016-10-01

Poly(γ-glutamic acid) mainly produced by Bacillus spp. is an industrially important compound due to several useful features. Among them, molecular weight is an important characteristic affecting on the physical properties such as viscosities and negative charge densities. However, it is difficult to control the molecular size of PGA since it decreases during fermentation. Previous study reported that PGA produced in the media containing different carbon sources such as glucose and glycerol showed differences in molecular weight. Therefore in this study, the effect of carbon source on the PGA molecular weight was examined; with the aim of developing a strategy to maintain the high molecular weight of PGA during fermentation. Our result showed that the weight average molecular weight (Mw) of PGA of Bacillus licheniformis ATCC 9945 cultivated in the media containing PTS-sugars were higher than the medium containing glycerol (non-PTS). The result of metabolome analysis indicated the possibility of CodY (a global regulator protein) activation in the cells cultivated in the media containing PTS-sugars. To mimic this effect, branched-chain amino acids (BCAAs), which are activators of CodY, were added to a medium containing glycerol. As the result, the Mw of PGA in the BCAAs-supplemented media were maintained and high during the early production phase compared to the non BCAAs-supplemented medium. These results indicate that BCAAs can repress the PGA molecular weight reduction during fermentation in B. licheniformis ATCC 9945. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Physicochemical Properties Analysis and Secretome of Aspergillus niger in Fermented Rapeseed Meal

PubMed Central

Shi, Changyou; He, Jun; Yu, Jie; Yu, Bing; Mao, Xiangbing; Zheng, Ping; Huang, Zhiqing; Chen, Daiwen

2016-01-01

The nutrient digestibility and feeding value of rapeseed meal (RSM) for non-ruminant animals is poor due to the presence of anti-nutritional substances such as glucosinolate, phytic acid, crude fiber etc. In the present study, a solid state fermentation (SSF) using Aspergillus niger was carried out with the purpose of improving the nutritional quality of RSM. The chemical composition and physicochemical properties of RSM before and after fermentation were compared. To further understand possible mechanism of solid state fermentation, the composition of extracellular enzymes secreted by Aspergillus niger during fermentation was analysed using two-dimentional difference gel electrophoresis (2D-DIGE) combined with matrix assisted laser desorption ionization—time of flight—mass spectrometer (MALDI-TOF-MS). Results of the present study indicated that SSF had significant effects on chemical composition of RSM. The fermented rapeseed meal (FRSM) contained more crude protein (CP) and amino acid (AA) (except His) than unfermented RSM. Notably, the small peptide in FRSM was 2.26 time larger than that in unfermented RSM. Concentrations of anti-nutritional substrates in FRSM including neutral detergent fiber (NDF), glucosinolates, isothiocyanate, oxazolidithione, and phytic acid declined (P < 0.05) by 13.47, 43.07, 55.64, 44.68 and 86.09%, respectively, compared with unfermented RSM. A. niger fermentation disrupted the surface structure, changed macromolecular organic compounds, and reduced the protein molecular weights of RSM substrate. Total proteins of raw RSM and FRSM were separated and 51 protein spots were selected for mass spectrometry according to 2D-DIGE map. In identified proteins, there were 15 extracellular hydrolases secreted by A. niger including glucoamylase, acid protease, beta-glucanase, arabinofuranosidase, xylanase, and phytase. Some antioxidant related enzymes also were identified. These findings suggested that A. niger is able to secrete many extracellular degradation enzymes (especially lignocellulosic hydrolyzing enzymes, acid proteases and phytase) during fermentation of RSM, thus altering chemical composition and physicochemical properties of RSM. PMID:27049858

Fermentation of soybean hulls to ethanol while retaining protein value

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mielenz, Jonathan R; Wyman, Professor Charles E; John, Bardsley

2009-01-01

Soybean hulls were evaluated as a resource for production of ethanol by the simultaneous saccharification and fermentation (SSF) process, and no pretreatment of the hulls was found to be needed to realize high ethanol yields with S. cerevisiae D5A. The impact of cellulase, -glucosidase and pectinase dosages were determined at a 15% biomass loading, and ethanol concentrations of 25-30 g/L were routinely obtained, while under these conditions corn stover, wheat straw, and switchgrass produced 3-4 times lower ethanol yields. Removal of carbohydrates also concentrated the hull protein to over 25% w/w from the original roughly 10%. Analysis of the soybeanmore » hulls before and after fermentation showed similar amino acid profiles including an increase in the essential amino acids lysine and threonine in the residues. Thus, eliminating pretreatment should assure that the protein in the hulls is preserved, and conversion of the carbohydrates to ethanol with high yields produces a more concentrated and valuable co-product in addition to ethanol. The resulting upgraded feed product from soybean hulls would likely to be acceptable to monogastric as well as bovine livestock.« less

Aroma profiling of an aerated fermentation of natural grape must with selected yeast strains at pilot scale.

PubMed

Tronchoni, Jordi; Curiel, José Antonio; Sáenz-Navajas, María Pilar; Morales, Pilar; de-la-Fuente-Blanco, Arancha; Fernández-Zurbano, Purificación; Ferreira, Vicente; Gonzalez, Ramon

2018-04-01

The use of non-Saccharomyces strains in aerated conditions has proven effective for alcohol content reduction in wine during lab-scale fermentation. The process has been scaled up to 20 L batches, in order to produce lower alcohol wines amenable to sensory analysis. Sequential instead of simultaneous inoculation was chosen to prevent oxygen exposure of Saccharomyces cerevisiae during fermentation, since previous results indicated that this would result in increased acetic acid production. In addition, an adaptation step was included to facilitate non-Saccharomyces implantation in natural must. Wines elaborated with Torulaspora delbrueckii or Metschnikowia pulcherrima in aerated conditions contained less alcohol than control wine (S. cerevisiae, non-aerated). Sensory and aroma analysis revealed that the quality of mixed fermentations was affected by the high levels of some yeast amino acid related byproducts, which suggests that further progress requires a careful selection of non-Saccharomyces strains and the use of specific N-nutrients. Copyright © 2017 Elsevier Ltd. All rights reserved.

Purification of gamma-amino butyric acid (GABA) from fermentation of defatted rice bran extract by using ion exchange resin

NASA Astrophysics Data System (ADS)

Tuan Nha, Vi; Phung, Le Thi Kim; Dat, Lai Quoc

2017-09-01

Rice bran is one of the significant byproducts of rice processing with 10 %w/w of constitution of whole rice grain. It is rich in nutrient compounds, including glutamic acid. Thus, it could be utilized for the fermentation with Lactobateria for synthesis of GABA, a valuable bioactive for antihypertensive effects. However, the concentration and purity of GABA in fermentation broth of defatted rice bran extract is low for production of GABA drug. This research focused on the purification of GABA from the fermentation broth of defatted rice bran extract by using cation exchange resin. The results indicate that, the adsorption isotherm of GABA by Purelite C100 showed the good agreement with Freundlich model, with high adsorption capacity. The effects of pH and concentration of NaCl in eluent on the elution were also investigated. The obtained results show that, at the operating conditions of elution as follows: pH 6.5, 0.8 M of NaCl in eluent, 0.43 of bed volume; concentration of GABA in accumulative eluent, the purity and recovery yield of GABA were 743.8 ppm, 44.0% and 84.2%, respectively. Results imply that, it is feasible to apply cation exchange resin for purification of GABA from fermentation broth of defatted rice bran extract.

Selection of lactic acid bacteria isolated from Tunisian cereals and exploitation of the use as starters for sourdough fermentation.

PubMed

Mamhoud, Asma; Nionelli, Luana; Bouzaine, Taroub; Hamdi, Moktar; Gobbetti, Marco; Rizzello, Carlo Giuseppe

2016-05-16

Wheat bread is the most popular staple food consumed in Tunisia and, despite the niche production of some typical breads (e.g. Tabouna, Mlawi, Mtabga), the major part is currently produced with baker's yeast at industrial or, mainly, at artisanal level, while the use of sourdough fermentation is rarely reported. Considering the growing national demand for cereal baked goods, it can be hypothesized that sourdough fermentation through the use of selected lactic acid bacteria as starters could improve the overall quality and the diversification of local products. Different cereal grains were collected from the regions of Ariana, Bizerta, Beja Nabeul, and Seliana, and the autochthonous lactic acid bacteria were isolated, identified, characterized and selected on the basis of the kinetics of acidification, the proteolytic activity, and the quotient of fermentation. Lactobacillus curvatus MA2, Pediococcus pentosaceus OA2, and Pediococcus acidilactici O1A1 were used together as mixed starter to obtain a selected sourdough. According to the backslopping procedure, a type I sourdough was made from a Tunisian flour (spontaneous sourdough). Compared to the use of the spontaneous sourdough, the one obtained with selected and mixed starters by a unique fermentation step, favored the increase of the concentrations of organic acids, phenols, and total free amino acids, the most suitable quotient of fermentation, and the most intense phytase and antioxidant activities, that increased ca. 20% compared to the control. Moreover, the selected starters improved the in vitro protein digestibility (ca. 82% when selected sourdough was used), textural and sensory features of the breads, as determined by textural profile analysis and panel test, respectively. This study aimed at exploiting the potential of selected autochthonous lactic acid bacteria and extending the use of a sourdough (type II), thanks to the set-up of a two-step fermentation protocol designed for application at the industrial level, and the confirmed nutritional, textural, and sensory advantages of the final product. Copyright © 2016 Elsevier B.V. All rights reserved.

Physicochemical Properties Analysis and Secretome of Aspergillus niger in Fermented Rapeseed Meal.

PubMed

Shi, Changyou; He, Jun; Yu, Jie; Yu, Bing; Mao, Xiangbing; Zheng, Ping; Huang, Zhiqing; Chen, Daiwen

2016-01-01

The nutrient digestibility and feeding value of rapeseed meal (RSM) for non-ruminant animals is poor due to the presence of anti-nutritional substances such as glucosinolate, phytic acid, crude fiber etc. In the present study, a solid state fermentation (SSF) using Aspergillus niger was carried out with the purpose of improving the nutritional quality of RSM. The chemical composition and physicochemical properties of RSM before and after fermentation were compared. To further understand possible mechanism of solid state fermentation, the composition of extracellular enzymes secreted by Aspergillus niger during fermentation was analysed using two-dimentional difference gel electrophoresis (2D-DIGE) combined with matrix assisted laser desorption ionization-time of flight-mass spectrometer (MALDI-TOF-MS). Results of the present study indicated that SSF had significant effects on chemical composition of RSM. The fermented rapeseed meal (FRSM) contained more crude protein (CP) and amino acid (AA) (except His) than unfermented RSM. Notably, the small peptide in FRSM was 2.26 time larger than that in unfermented RSM. Concentrations of anti-nutritional substrates in FRSM including neutral detergent fiber (NDF), glucosinolates, isothiocyanate, oxazolidithione, and phytic acid declined (P < 0.05) by 13.47, 43.07, 55.64, 44.68 and 86.09%, respectively, compared with unfermented RSM. A. niger fermentation disrupted the surface structure, changed macromolecular organic compounds, and reduced the protein molecular weights of RSM substrate. Total proteins of raw RSM and FRSM were separated and 51 protein spots were selected for mass spectrometry according to 2D-DIGE map. In identified proteins, there were 15 extracellular hydrolases secreted by A. niger including glucoamylase, acid protease, beta-glucanase, arabinofuranosidase, xylanase, and phytase. Some antioxidant related enzymes also were identified. These findings suggested that A. niger is able to secrete many extracellular degradation enzymes (especially lignocellulosic hydrolyzing enzymes, acid proteases and phytase) during fermentation of RSM, thus altering chemical composition and physicochemical properties of RSM.

Use of sourdough fermentation and pseudo-cereals and leguminous flours for the making of a functional bread enriched of gamma-aminobutyric acid (GABA).

PubMed

Coda, Rossana; Rizzello, Carlo Giuseppe; Gobbetti, Marco

2010-02-28

Lactobacillus plantarum C48 and Lactococcus lactis subsp. lactis PU1, previously selected for the biosynthesis of gamma-aminobutyric acid (GABA), were used for sourdough fermentation of cereal, pseudo-cereal and leguminous flours. Chickpea, amaranth, quinoa and buckwheat were the flours most suitable to be enriched of GABA. The parameters of sourdough fermentation were optimized. Addition of 0.1mM pyridoxal phosphate, dough yield of 160, inoculum of 5 x 10(7)CFU/g of starter bacteria and fermentation for 24h at 30 degrees C were found to be the optimal conditions. A blend of buckwheat, amaranth, chickpea and quinoa flours (ratio 1:1:5.3:1) was selected and fermented with baker's yeast (non-conventional flour bread, NCB) or with Lb. plantarum C48 sourdough (non-conventional flour sourdough bread, NCSB) and compared to baker's yeast started wheat flour bread (WFB). NCSB had the highest concentration of free amino acids and GABA (ca. 4467 and 504 mg/kg, respectively). The concentration of phenolic compounds and antioxidant activity of NCSB bread was the highest, as well as the rate of in vitro starch hydrolysis was the lowest. Texture analysis showed that sourdough fermentation enhances several characteristics of NCSB with respect to NCB, thus approaching the features of WFB. Sensory analysis showed that sourdough fermentation allowed to get good palatability and overall taste appreciation. (c) 2009 Elsevier B.V. All rights reserved.

Quantification of nitrogen in the liquid fraction and in vitro assessment of lysine bioavailability in the solid fraction of soybean meal hydrolysates.

PubMed

Luján-Rhenals, D; Morawicki, R; Shi, Z; Ricke, S C

2018-01-02

Soybean meal (SBM) is a product generated from the manufacture of soybean oil and has the potential for use as a source of fermentable sugars for ethanol production or as a protein source for animal feeds. Knowing the levels of nitrogen available from ammonium is a necessary element of the ethanolic fermentation process while identifying the levels of essential amino acids such as lysine is important in determining usage as a feed source. As such the purpose of this study was to quantify total nitrogen and ammonium in the liquid fraction of hydrolyzed SBM and to evaluate total and bioavailable lysine in the solid fraction of the hydrolyzed SBM. The effects of acid concentration, cellulase and β-glucosidase on total and ammonium nitrogen were studied with analysis indicating that higher acid concentrations increased nitrogen compounds with ammonium concentrations ranging from 0.20 to 1.24 g L -1 while enzymatic treatments did not significantly increase nitrogen levels. Total and bioavailable lysine was quantified by use of an auxotrophic gfpmut3 E.coli whole-cell bioassay organism incapable of lysine biosynthesis. Acid and enzymatic treatments were applied with lysine bioavailability increasing from a base of 82% for untreated SBM to up to 97%. Our results demonstrated that SBM has the potential to serve in ethanolic fermentation and as an optimal source essential amino acid lysine.

Lactic acid bacteria in the quality improvement and depreciation of wine.

PubMed

Lonvaud-Funel, A

1999-01-01

The winemaking process includes two main steps: lactic acid bacteria are responsible for the malolactic fermentation which follows the alcoholic fermentation by yeasts. Both types of microorganisms are present on grapes and on cellar equipment. Yeasts are better adapted to growth in grape must than lactic acid bacteria, so the alcoholic fermentation starts quickly. In must, up to ten lactic acid bacteria species can be identified. They belong to the Lactobacillus, Pediococcus, Leuconostoc and Oenococcus genera. Throughout alcoholic fermentation, a natural selection occurs and finally the dominant species is O. oeni, due to interactions between yeasts and bacteria and between bacteria themselves. After bacterial growth, when the population is over 10(6) CFU/ml, malolactic transformation is the obvious change in wine composition. However, many other substrates can be metabolized. Some like remaining sugars and citric acid are always assimilated by lactic acid bacteria, thus providing them with energy and carbon. Other substrates such as some amino acids may be used following pathways restricted to strains carrying the adequate enzymes. Some strains can also produce exopolysaccharides. All these transformations greatly influence the sensory and hygienic quality of wine. Malic acid transformation is encouraged because it induces deacidification. Diacetyl produced from citric acid is also helpful to some extent. Sensory analyses show that many other reactions change the aromas and make malolactic fermentation beneficial, but they are as yet unknown. On the contrary, an excess of acetic acid, the synthesis of glucane, biogenic amines and precursors of ethylcarbamate are undesirable. Fortunately, lactic acid bacteria normally multiply in dry wines; moreover some of these activities are not widespread. Moreover, the most striking trait of wine lactic acid bacteria is their capacity to adapt to a hostile environment. The mechanisms for this are not yet completely elucidated. Molecular biology has provided some explanations for the behaviour and the metabolism of bacteria in wine. New tools are now available to detect the presence of desirable and undesirable strains. Even if much remains unknown, winemakers and oenologists can nowadays better control the process. By acting upon the diverse microflora and grape musts, they are more able to produce healthy and pleasant wines.

Amino Acid Selective 13C Labeling and 13C Scrambling Profile Analysis of Protein α and Side-Chain Carbons in Escherichia coli Utilized for Protein Nuclear Magnetic Resonance.

PubMed

Sugiki, Toshihiko; Furuita, Kyoko; Fujiwara, Toshimichi; Kojima, Chojiro

2018-06-20

Amino acid selective isotope labeling is an important nuclear magnetic resonance technique, especially for larger proteins, providing strong bases for the unambiguous resonance assignments and information concerning the structure, dynamics, and intermolecular interactions. Amino acid selective 15 N labeling suffers from isotope dilution caused by metabolic interconversion of the amino acids, resulting in isotope scrambling within the target protein. Carbonyl 13 C atoms experience less isotope scrambling than the main-chain 15 N atoms do. However, little is known about the side-chain 13 C atoms. Here, the 13 C scrambling profiles of the Cα and side-chain carbons were investigated for 15 N scrambling-prone amino acids, such as Leu, Ile, Tyr, Phe, Thr, Val, and Ala. The level of isotope scrambling was substantially lower in 13 Cα and 13 C side-chain labeling than in 15 N labeling. We utilized this reduced scrambling-prone character of 13 C as a simple and efficient method for amino acid selective 13 C labeling using an Escherichia coli cold-shock expression system and high-cell density fermentation. Using this method, the 13 C labeling efficiency was >80% for Leu and Ile, ∼60% for Tyr and Phe, ∼50% for Thr, ∼40% for Val, and 30-40% for Ala. 1 H- 15 N heteronuclear single-quantum coherence signals of the 15 N scrambling-prone amino acid were also easily filtered using 15 N-{ 13 Cα} spin-echo difference experiments. Our method could be applied to the assignment of the 55 kDa protein.

The role of oxygen in the liquid fermentation of wheat bran.

PubMed

Savolainen, Otto I; Coda, Rossana; Suomi, Katja; Katina, Kati; Juvonen, Riikka; Hanhineva, Kati; Poutanen, Kaisa

2014-06-15

The extensive use of wheat bran as a food ingredient is limited due to its bitter taste and hard texture. To overcome these, some preprocessing methods, such as fermentation with yeast and lactic acid bacteria or enzymatic treatments have been proposed. The current work studied microbial communities, acidification, ethanol formation and metabolite profile of wheat bran fermented in either aerated or anaerobic conditions. In aerated conditions, yeasts grew better and the production of organic acids was smaller, and hence pH was higher. In anaerobic conditions, lactic acid bacteria and endogenous heterotrophic bacteria grew better. Aeration had a large effect on the sourdough metabolite profile, as analyzed by UPLC-qTOF-MS. Anaerobic conditions induced degradation of ferulic and caffeic acids, whereas the amount of sinapic acid increased. Aeration caused degradation of amino acids and hydroxycinnamic acid derivatives of polyamines. The results suggest that the control of oxygen could be used for tailoring the properties of bran sourdough. Copyright © 2013 Elsevier Ltd. All rights reserved.

No-Cook Process for Ethanol Production Using Indian Broken Rice and Pearl Millet

PubMed Central

Gohel, Vipul; Duan, Gang

2012-01-01

No-cook process using granular starch hydrolyzing enzyme (GSHE) was evaluated for Indian broken rice and pearl millet. One-factor-at-a-time optimization method was used in ethanol production to identify optimum concentration of GSHE, under yeast fermentation conditions using broken rice and pearl millet as fermentation feedstocks. An acid fungal protease at a concentration of 0.2 kg per metric ton of grain was used along with various dosages of GSHE under yeast fermentation conditions to degrade the grain proteins into free amino nitrogen for yeast growth. To measure the efficacy of GSHE to hydrolyze no-cook broken rice and pearl millet, the chemical composition, fermentation efficiency, and ethanol recovery were determined. In both feedstocks, fermentation efficiency and ethanol recovery obtained through single-step no-cook process were higher than conventional multistep high-temperature process, currently considered the ideal industrial process. Furthermore, the no-cook process can directly impact energy consumption through steam saving and reducing the water cooling capacity needs, compared to conventional high-temperature process. PMID:22518148

Microbial community structure in fermentation process of Shaoxing rice wine by Illumina-based metagenomic sequencing.

PubMed

Xie, Guangfa; Wang, Lan; Gao, Qikang; Yu, Wenjing; Hong, Xutao; Zhao, Lingyun; Zou, Huijun

2013-09-01

To understand the role of the community structure of microbes in the environment in the fermentation of Shaoxing rice wine, samples collected from a wine factory were subjected to Illumina-based metagenomic sequencing. De novo assembly of the sequencing reads allowed the characterisation of more than 23 thousand microbial genes derived from 1.7 and 1.88 Gbp of sequences from two samples fermented for 5 and 30 days respectively. The microbial community structure at different fermentation times of Shaoxing rice wine was revealed, showing the different roles of the microbiota in the fermentation process of Shaoxing rice wine. The gene function of both samples was also studied in the COG database, with most genes belonging to category S (function unknown), category E (amino acid transport and metabolism) and unclassified group. The results show that both the microbial community structure and gene function composition change greatly at different time points of Shaoxing rice wine fermentation. © 2013 Society of Chemical Industry.

Optimization of fermentation parameters to study the behavior of selected lactic cultures on soy solid state fermentation.

PubMed

Rodríguez de Olmos, A; Bru, E; Garro, M S

2015-03-02

The use of solid fermentation substrate (SSF) has been appreciated by the demand for natural and healthy products. Lactic acid bacteria and bifidobacteria play a leading role in the production of novel functional foods and their behavior is practically unknown in these systems. Soy is an excellent substrate for the production of functional foods for their low cost and nutritional value. The aim of this work was to optimize different parameters involved in solid state fermentation (SSF) using selected lactic cultures to improve soybean substrate as a possible strategy for the elaboration of new soy food with enhanced functional and nutritional properties. Soy flour and selected lactic cultures were used under different conditions to optimize the soy SSF. The measured responses were bacterial growth, free amino acids and β-glucosidase activity, which were analyzed by applying response surface methodology. Based on the proposed statistical model, different fermentation conditions were raised by varying the moisture content (50-80%) of the soy substrate and temperature of incubation (31-43°C). The effect of inoculum amount was also investigated. These studies demonstrated the ability of selected strains (Lactobacillus paracasei subsp. paracasei and Bifidobacterium longum) to grow with strain-dependent behavior on the SSF system. β-Glucosidase activity was evident in both strains and L. paracasei subsp. paracasei was able to increase the free amino acids at the end of fermentation under assayed conditions. The used statistical model has allowed the optimization of fermentation parameters on soy SSF by selected lactic strains. Besides, the possibility to work with lower initial bacterial amounts to obtain results with significant technological impact was demonstrated. Copyright © 2014 Elsevier B.V. All rights reserved.

Analysis of metabolomic profile of fermented Orostachys japonicus A. Berger by capillary electrophoresis time of flight mass spectrometry

PubMed Central

Das, Gitishree; Patra, Jayanta Kumar; Lee, Sun-Young; Kim, Changgeon; Park, Jae Gyu

2017-01-01

Microbial cell performance in food biotechnological processes has become an important concern for improving human health worldwide. Lactobacillus plantarum, which is widely distributed in nature, is a lactic acid bacterium with many industrial applications for fermented foods or functional foods (e.g., probiotics). In the present study, using capillary electrophoresis time of flight mass spectrometry, the metabolomic profile of dried Orostachys japonicus A. Berger, a perennial medicinal herb with L. plantarum was compared with that of O. japonicus fermented with L. plantarum to elucidate the metabolomic changes induced by the fermentation process. The levels of several metabolites were changed by the fermentation process, indicating their involvement in microbial performance. For example, glycolysis, the pentose phosphate pathway, the TCA cycle, the urea cycle-related metabolism, nucleotide metabolism, and lipid and amino acid metabolism were altered significantly by the fermentation process. Although the fermented metabolites were not tested using in vivo studies to increase human health benefits, our findings provide an insight into the alteration of metabolites induced by fermentation, and indicated that the metabolomic analysis for the process should be accompanied by fermenting strains and conditions. PMID:28704842

Microbe participation in aroma production during soy sauce fermentation.

PubMed

Harada, Risa; Yuzuki, Masanobu; Ito, Kotaro; Shiga, Kazuki; Bamba, Takeshi; Fukusaki, Eiichiro

2018-06-01

Soy sauce is a traditional Japanese fermented seasoning that contains various constituents such as amino acids, organic acids, and volatiles that are produced during the long fermentation process. Although studies regarding the correlation between microbes and aroma constituents have been performed, there are no reports about the influences of the microbial products, such as lactic acid, acetic acid, and ethanol, during fermentation. Because it is known that these compounds contribute to microbial growth and to changes in the constituent profile by altering the moromi environment, understanding the influence of these compounds is important. Metabolomics, the comprehensive study of low molecular weight metabolites, is a promising strategy for the deep understanding of constituent contributions to food characteristics. Therefore, the influences of microbes and their products such as lactic acid, acetic acid, and ethanol on aroma profiles were investigated using gas chromatography/mass spectrometry (GC/MS)-based metabolic profiling. The presence of aroma constituents influenced by microbes and chemically influenced by lactic acid, acetic acid, and ethanol were proposed. Most of the aroma constituents were not produced by adding ethanol alone, confirming the participation of yeast in aroma production. It was suggested that lactic acid bacterium relates to a key aromatic compound, 2,5-dimethyl-4-hydroxy-3(2H)-furanone. However, most of the measured aroma constituents changed similarly in both samples with lactic acid bacterium and acids. Thus, it was clear that the effect of lactic acid and acetic acid on the aroma profile was significant. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Bacterial dynamics and metabolite changes in solid-state acetic acid fermentation of Shanxi aged vinegar.

PubMed

Li, Sha; Li, Pan; Liu, Xiong; Luo, Lixin; Lin, Weifeng

2016-05-01

Solid-state acetic acid fermentation (AAF), a natural or semi-controlled fermentation process driven by reproducible microbial communities, is an important technique to produce traditional Chinese cereal vinegars. Highly complex microbial communities and metabolites are involved in traditional Chinese solid-state AAF, but the association between microbiota and metabolites during this process are still poorly understood. In this study, we performed amplicon 16S rRNA gene sequencing on the Illumina MiSeq platform, PCR-denaturing gradient gel electrophoresis, and metabolite analysis to trace the bacterial dynamics and metabolite changes under AAF process. A succession of bacterial assemblages was observed during the AAF process. Lactobacillales dominated all the stages. However, Acetobacter species in Rhodospirillales were considerably accelerated during AAF until the end of fermentation. Quantitative PCR results indicated that the biomass of total bacteria showed a "system microbe self-domestication" process in the first 3 days, and then peaked at the seventh day before gradually decreasing until the end of AAF. Moreover, a total of 88 metabolites, including 8 organic acids, 16 free amino acids, and 66 aroma compounds were detected during AAF. Principal component analysis and cluster analyses revealed the high correlation between the dynamics of bacterial community and metabolites.

Analysis of metabolomic profile of fermented Orostachys japonicus A. Berger by capillary electrophoresis time of flight mass spectrometry.

PubMed

Das, Gitishree; Patra, Jayanta Kumar; Lee, Sun-Young; Kim, Changgeon; Park, Jae Gyu; Baek, Kwang-Hyun

2017-01-01

Microbial cell performance in food biotechnological processes has become an important concern for improving human health worldwide. Lactobacillus plantarum, which is widely distributed in nature, is a lactic acid bacterium with many industrial applications for fermented foods or functional foods (e.g., probiotics). In the present study, using capillary electrophoresis time of flight mass spectrometry, the metabolomic profile of dried Orostachys japonicus A. Berger, a perennial medicinal herb with L. plantarum was compared with that of O. japonicus fermented with L. plantarum to elucidate the metabolomic changes induced by the fermentation process. The levels of several metabolites were changed by the fermentation process, indicating their involvement in microbial performance. For example, glycolysis, the pentose phosphate pathway, the TCA cycle, the urea cycle-related metabolism, nucleotide metabolism, and lipid and amino acid metabolism were altered significantly by the fermentation process. Although the fermented metabolites were not tested using in vivo studies to increase human health benefits, our findings provide an insight into the alteration of metabolites induced by fermentation, and indicated that the metabolomic analysis for the process should be accompanied by fermenting strains and conditions.

Sch9p kinase and the Gcn4p transcription factor regulate glycerol production during winemaking.

PubMed

Vallejo, Beatriz; Orozco, Helena; Picazo, Cecilia; Matallana, Emilia; Aranda, Agustín

2017-01-01

Grape juice fermentation is a harsh environment with many stressful conditions, and Saccharomyces cerevisiae adapts its metabolism in response to those environmental challenges. Many nutrient-sensing pathways control this feature. The Tor/Sch9p pathway promotes growth and protein synthesis when nutrients are plenty, while the transcription factor Gcn4p is required for the activation of amino acid biosynthetic pathways. We previously showed that Sch9p impact on longevity depends on the nitrogen/carbon ratio. When nitrogen is limiting, SCH9 deletion shortens chronological life span, which is the case under winemaking conditions. Its deletion also increases glycerol during fermentation, so the impact of this pathway on metabolism under winemaking conditions was studied by transcriptomic and metabolomic approaches. SCH9 deletion causes the upregulation of many amino acid biosynthesis pathways. When Gcn4p was overexpressed during winemaking, increased glycerol production was also observed. Therefore, both pathways are related in terms of glycerol production. SCH9 deletion increased the amount of the limiting enzyme in glycerol biosynthesis, glycerol-3-P dehydrogenase Gpd1p at the protein level. The impact on the metabolome of SCH9 deletion and GCN4 overexpression differed, although both showed a downregulation of glycolysis. SCH9 deletion downregulated the amount of most proteinogenic amino acids and increased the amount of lipids, such as ergosterol. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Iranian wheat flours from rural and industrial mills: Exploitation of the chemical and technology features, and selection of autochthonous sourdough starters for making breads.

PubMed

Pontonio, Erica; Nionelli, Luana; Curiel, José Antonio; Sadeghi, Alireza; Di Cagno, Raffaella; Gobbetti, Marco; Rizzello, Carlo Giuseppe

2015-05-01

This study aimed at describing the main chemical and technology features of eight Iranian wheat flours collected from industrial and artisanal mills. Their suitability for bread making was investigated using autochthonous sourdough starters. Chemical analyses showed high concentration of fibers and ash, and technology aptitude for making breads. As shown through 2-DE analyses, gliadin and glutenin subunits were abundant and varied among the flours. According to the back slopping procedure, type I sourdoughs were prepared from Iranian flours, and lactic acid bacteria were typed and identified. Strains of Pediococcus pentosaceus, Weissella cibaria, Weissella confusa, and Leuconostoc citreum were the most abundant. Based on the kinetics of growth and acidification, quotient of fermentation and concentration of total free amino acids, lactic acid bacteria were selected and used as sourdough mixed starters for bread making. Compared to spontaneous fermentation, sourdoughs fermented with selected and mixed starters favored the increase of the concentrations of organic acids and total free amino acids, the most suitable quotient of fermentation, and the most intense phytase and antioxidant activities. Although the high concentration of fibers, selected and mixed starters improved the textural features of the breads. This study might had contribute to the exploitation of the potential of Iranian wheat flours and to extend the use of sourdough, showing positive technology, nutritional and, probably, economic repercussions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of amino acids on tannase biosynthesis by Bacillus licheniformis KBR6.

PubMed

Mohapatra, Pradeep K Das; Pati, Bikas R; Mondal, Keshab C

2009-04-01

Microbial tannase (tannin acyl hydrolase, EC 3.1.1.20), a hydrolysable tannin-degrading enzyme, has gained importance in various industrial processes, and is used extensively in the manufacture of instant tea, beer, wine, and gallic acid. Tannase is an inducible enzyme, and hydrolysable tannin, especially tannic acid, is the sole inducer. This study is of the effect of various amino acids and their analogues on tannase biosynthesis by Bacillus licheniformis KBR6 to ascertain the mode of action of these growth factors on tannase biosynthesis from microbial origin. Enzyme production was carried out in enriched tannic acid medium through submerged fermentation for 20 h at 35 degrees C. Different amino acids at a concentration of 0.05 g% (w/v) were added to the culture medium immediately after sterilization. Culture supernatant was used as the source of the enzyme and the quantity of tannase was estimated by the colorimetric assay method. Growth of the organism was estimated according to biomass dry weight. Maximum tannase (2.87-fold that of the control) was synthesized by B. licheniformis KBR6 when alanine was added to the culture medium. Other amino acids, such as DL-serine, L-cystine, glycine, L-ornithine, aspartic acid, L-glutamic acid, DL-valine, L-leucine and L-lysine, also induced tannase synthesis. L-Cysteine monohydrochloride and DL-threonine were the most potent inhibitors. Regulation of tannase biosynthesis by B. licheniformis in the presence of various amino acids is shown. This information will be helpful for formulating an enriched culture medium for industrial-scale tannase production.

Observation of CO 2 in Fourier transform infrared spectral measurements of living Acholeplasma laidlawii cells

NASA Astrophysics Data System (ADS)

Omura, Yoko; Okazaki, Norio

2003-06-01

In monitoring the time course of conformational disorder by Fourier transform infrared spectroscopy for intact Acholeplasma laidlawii cells grown at 37 °C on binary fatty acid mixtures containing oleic acid and for cells grown on pure palmitic acid, an absorption band at 2343 cm-1 was observed. The band intensity was found to increase with time. This band was not observed in the spectra for isolated membranes. It is suggested that the 2343 cm-1 band is due to CO2 dissolved in water, most likely produced at the final point of fermentation of amino acid by this microorganism.

Effect of halotolerant starter microorganisms on chemical characteristics of fermented chum salmon (Oncorhynchus keta) sauce.

PubMed

Yoshikawa, Shuji; Kurihara, Hideyuki; Kawai, Yuji; Yamazaki, Koji; Tanaka, Akira; Nishikiori, Takafumi; Ohta, Tomoki

2010-05-26

Chum salmon sauce mash was inoculated with barley koji (barley steamed and molded with Aspergillus oryzae ) and halotolerant microorganisms (HTMs), Zygosaccharomyces rouxii , Candida versatilis , and Tetragenococcus halophilus , in nine different combinations under non-aseptic conditions similar to the industrial fish sauce production and fermented at 35 +/- 2.5 degrees C for 84 days. The changes in the chemical components, color, and sensory properties during fermentation were investigated. Free amino acid content was increased, and the browning of fish sauce was enhanced by the usage of barley koji during fermentation. The halotolerant yeast (HTY) produced ethanol and repressed the browning by consumption of reducing sugar. Inoculated Z. rouxii in the fish sauce mash produced 2-phenylethanol (2-PE) and 4-hydoxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone (HEMF), and C. versatilis in the fish sauce mash produced 4-ethylguaiacol (4-EG), known as characteristic flavor compounds in soy sauce, adding soy-sauce-like flavor to the fish sauce. Thus, inoculation of HTMs and barley koji was effective for conferring the soy-sauce-like flavor and increasing free amino acid and ethanol contents in fish sauce product.

Dynamics of the Saccharomyces cerevisiae Transcriptome during Bread Dough Fermentation

PubMed Central

Aslankoohi, Elham; Zhu, Bo; Rezaei, Mohammad Naser; Voordeckers, Karin; De Maeyer, Dries; Marchal, Kathleen; Dornez, Emmie

2013-01-01

The behavior of yeast cells during industrial processes such as the production of beer, wine, and bioethanol has been extensively studied. In contrast, our knowledge about yeast physiology during solid-state processes, such as bread dough, cheese, or cocoa fermentation, remains limited. We investigated changes in the transcriptomes of three genetically distinct Saccharomyces cerevisiae strains during bread dough fermentation. Our results show that regardless of the genetic background, all three strains exhibit similar changes in expression patterns. At the onset of fermentation, expression of glucose-regulated genes changes dramatically, and the osmotic stress response is activated. The middle fermentation phase is characterized by the induction of genes involved in amino acid metabolism. Finally, at the latest time point, cells suffer from nutrient depletion and activate pathways associated with starvation and stress responses. Further analysis shows that genes regulated by the high-osmolarity glycerol (HOG) pathway, the major pathway involved in the response to osmotic stress and glycerol homeostasis, are among the most differentially expressed genes at the onset of fermentation. More importantly, deletion of HOG1 and other genes of this pathway significantly reduces the fermentation capacity. Together, our results demonstrate that cells embedded in a solid matrix such as bread dough suffer severe osmotic stress and that a proper induction of the HOG pathway is critical for optimal fermentation. PMID:24056467

Dynamics of the Saccharomyces cerevisiae transcriptome during bread dough fermentation.

PubMed

Aslankoohi, Elham; Zhu, Bo; Rezaei, Mohammad Naser; Voordeckers, Karin; De Maeyer, Dries; Marchal, Kathleen; Dornez, Emmie; Courtin, Christophe M; Verstrepen, Kevin J

2013-12-01

The behavior of yeast cells during industrial processes such as the production of beer, wine, and bioethanol has been extensively studied. In contrast, our knowledge about yeast physiology during solid-state processes, such as bread dough, cheese, or cocoa fermentation, remains limited. We investigated changes in the transcriptomes of three genetically distinct Saccharomyces cerevisiae strains during bread dough fermentation. Our results show that regardless of the genetic background, all three strains exhibit similar changes in expression patterns. At the onset of fermentation, expression of glucose-regulated genes changes dramatically, and the osmotic stress response is activated. The middle fermentation phase is characterized by the induction of genes involved in amino acid metabolism. Finally, at the latest time point, cells suffer from nutrient depletion and activate pathways associated with starvation and stress responses. Further analysis shows that genes regulated by the high-osmolarity glycerol (HOG) pathway, the major pathway involved in the response to osmotic stress and glycerol homeostasis, are among the most differentially expressed genes at the onset of fermentation. More importantly, deletion of HOG1 and other genes of this pathway significantly reduces the fermentation capacity. Together, our results demonstrate that cells embedded in a solid matrix such as bread dough suffer severe osmotic stress and that a proper induction of the HOG pathway is critical for optimal fermentation.

Detoxification of acidic biorefinery waste liquor for production of high value amino acid.

PubMed

Christopher, Meera; Anusree, Murali; Mathew, Anil K; Nampoothiri, K Madhavan; Sukumaran, Rajeev Kumar; Pandey, Ashok

2016-08-01

The current study evaluates the detoxification of acid pretreatment liquor (APL) using adsorbent (ADS 400 & ADS 800) or ion-exchange (A-27MP & A-72MP) resins and its potential for amino acid production. The APL is generated as a by-product from the pretreatment of lignocellulosic biomass and is rich monomeric sugars as well as sugar degradation products (fermentation inhibitors) such as furfural and hydroxymethyl furfural (HMF). Of the four resins compared, ADS 800 removed approximately 85% and 60% of furfural and HMF, respectively. ADS 800 could be reused for up to six cycles after regeneration without losing its adsorption properties. The study was further extended by assessing the fermentability of detoxified APL for l-lysine production using wild and mutant strains of Corynebacterium glutamicum. The detoxified APL was superior to APL for l-lysine production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fermentation of quinoa and wheat slurries by Lactobacillus plantarum CRL 778: proteolytic activity.

PubMed

Dallagnol, Andrea Micaela; Pescuma, Micaela; De Valdez, Graciela Font; Rollán, Graciela

2013-04-01

Quinoa fermentation by lactic acid bacteria (LAB) is an interesting alternative to produce new bakery products with high nutritional value; furthermore, they are suitable for celiac patients because this pseudo-cereal contains no gluten. Growth and lactic acid production during slurry fermentations by Lactobacillus plantarum CRL 778 were greater in quinoa (9.8 log cfu/mL, 23.1 g/L) than in wheat (8.9 log cfu/mL, 13.9 g/L). Lactic fermentation indirectly stimulated flour protein hydrolysis by endogenous proteases of both slurries. However, quinoa protein hydrolysis was faster, reaching 40-100% at 8 h of incubation, while wheat protein hydrolysis was only 0-20%. In addition, higher amounts of peptides (24) and free amino acids (5 g/L) were determined in quinoa compared to wheat. Consequently, greater concentrations (approx. 2.6-fold) of the antifungal compounds (phenyllactic and hydroxyphenyllactic acids) were synthesized from Phe and Tyr in quinoa by L. plantarum CRL 778, an antifungal strain. These promising results suggest that this LAB strain could be used in the formulation of quinoa sourdough to obtain baked goods with improved nutritional quality and shelf life, suitable for celiac patients.

Comparison of free amino acids, antioxidants, soluble phenolic acids, cytotoxicity and immunomodulation of fermented mung bean and soybean.

PubMed

Ali, Norlaily Mohd; Yeap, Swee-Keong; Yusof, Hamidah Mohd; Beh, Boon-Kee; Ho, Wan-Yong; Koh, Soo-Peng; Abdullah, Mohd Puad; Alitheen, Noorjahan Banu; Long, Kamariah

2016-03-30

Mung bean and soybean have been individually reported previously to have antioxidant, cytotoxic and immunomodulatory effects, while fermentation is a well-known process to enhance the bioactive compounds that contribute to higher antioxidant, cytotoxic and immunomodulation effects. In this study, the free amino acids profile, soluble phenolic acids content, antioxidants, cytotoxic and immunomodulatory effects of fermented and non-fermented mung bean and soybean were compared. Fermented mung bean was recorded to have the highest level of free amino acids, soluble phenolic acids (especially protocatechuic acid) and antioxidant activities among all the tested products. Both fermented mung bean and soybean possessed cytotoxicity activities against breast cancer MCF-7 cells by arresting the G0/G1 phase followed by apoptosis. Moreover, fermented mung bean and soybean also induced splenocyte proliferation and enhanced the levels of serum interleukin-2 and interferon-γ. Augmented amounts of free amino acids and phenolic acids content after fermentation enhanced the antioxidants, cytotoxicity and immunomodulation effects of mung bean and soybean. More specifically, fermented mung bean showed the best effects among all the tested products. This study revealed the potential of fermented mung bean and soybean as functional foods for maintenance of good health. © 2015 Society of Chemical Industry.

L-Methionine Production.

PubMed

Shim, Jihyun; Shin, Yonguk; Lee, Imsang; Kim, So Young

L-Methionine has been used in various industrial applications such as the production of feed and food additives and has been used as a raw material for medical supplies and drugs. It functions not only as an essential amino acid but also as a physiological effector, for example, by inhibiting fat accumulation and enhancing immune response. Producing methionine from fermentation is beneficial in that microorganisms can produce L-methionine selectively using eco-sustainable processes. Nevertheless, the fermentative method has not been used on an industrial scale because it is not competitive economically compared with chemical synthesis methods. Presented are efforts to develop suitable strains, engineered enzymes, and alternative process of producing L-methionine that overcomes problems of conventional fermentation methods. One of the alternative processes is a two-step process in which the L-methionine precursor is produced by fermentation and then converted to L-methionine by enzymes. Directed efforts toward strain development and enhanced enzyme engineering will advance industrial production of L-methionine based on fermentation.

Enhancement of ε-poly-L-lysine (ε-PL) production by a novel producer Bacillus cereus using metabolic precursors and glucose feeding.

PubMed

Chheda, Anuj H; Vernekar, Madhavi R

2015-10-01

Epsilon poly-L-lysine (ε-PL) is a homo-biopolymer with approximately 25-30 L-lysine residues. It is a promising natural biopolymer widely used in food and pharmaceutical industry. The present work reports enhanced production of ε-PL with a novel producer Bacillus cereus using amino acids and TCA cycle intermediates in the fermentation medium. Among the various amino acids and TCA cycle intermediates tested 2 mM L-aspartic acid and 5 mM citric acid gave ε-PL yield of 145.5 and 230 mg/L, respectively. A combination of citric acid after 24 h and L-aspartic acid after 36 h improved ε-PL yield from 85 mg/L (control) to 335 mg/L. Glucose feeding strategy along with metabolic precursors was employed which further enhanced ε-PL yield to 565 mg/L. Thus, more than sixfold increase in ε-PL yield was achieved suggesting the potential of Bacillus cereus as a novel ε-PL producer.

Enzymes in Fermented Fish.

PubMed

Giyatmi; Irianto, H E

Fermented fish products are very popular particularly in Southeast Asian countries. These products have unique characteristics, especially in terms of aroma, flavor, and texture developing during fermentation process. Proteolytic enzymes have a main role in hydrolyzing protein into simpler compounds. Fermentation process of fish relies both on naturally occurring enzymes (in the muscle or the intestinal tract) as well as bacteria. Fermented fish products processed using the whole fish show a different characteristic compared to those prepared from headed and gutted fish. Endogenous enzymes like trypsin, chymotrypsin, elastase, and aminopeptidase are the most involved in the fermentation process. Muscle tissue enzymes like cathepsins, peptidases, transaminases, amidases, amino acid decarboxylases, glutamic dehydrogenases, and related enzymes may also play a role in fish fermentation. Due to the decreased bacterial number during fermentation, contribution of microbial enzymes to proteolysis may be expected prior to salting of fish. Commercial enzymes are supplemented during processing for specific purposes, such as quality improvement and process acceleration. In the case of fish sauce, efforts to accelerate fermentation process and to improve product quality have been studied by addition of enzymes such as papain, bromelain, trypsin, pepsin, and chymotrypsin. © 2017 Elsevier Inc. All rights reserved.

Microbial diversity and component variation in Xiaguan Tuo Tea during pile fermentation

PubMed Central

Li, Min; Yang, Xinrui; Gui, Xin; Chen, Guofeng; Chu, Jiuyun; He, Xingwang; Wang, Weitao; Han, Feng

2018-01-01

Xiaguan Tuo Tea is largely consumed by the Chinese, but there is little research into the microbial diversity and component changes during the fermentation of this tea. In this study, we first used fluorescence in situ hybridization (FISH), next-generation sequencing (NGS) and chemical analysis methods to determine the microbial abundance and diversity and the chemical composition during fermentation. The FISH results showed that the total number of microorganisms ranges from 2.3×102 to 4.0×108 cells per gram of sample during fermentation and is mainly dominated by fungi. In the early fermentation stages, molds are dominant (0.6×102~2.8×106 cells/g, 0~35 d). However, in the late stages of fermentation, yeasts are dominant (3.6×104~9.6×106 cells/g, 35~56 d). The bacteria have little effect during the fermentation of tea (102~103 cells/g, <1% of fungus values). Of these fungi, A. niger (Aspergillus niger) and B. adeninivorans (Blastobotrys adeninivorans) are identified as the two most common strains, based on Next-generation Sequencing (NGS) analysis. Peak diversity in tea was observed at day 35 of fermentation (Shannon–Weaver index: 1.195857), and lower diversity was observed on days 6 and 56 of fermentation (Shannon–Weaver index 0.860589 and 1.119106, respectively). During the microbial fermentation, compared to the unfermented tea, the tea polyphenol content decreased by 54%, and the caffeine content increased by 59%. Theanine and free amino acid contents were reduced during fermentation by 81.1 and 92.85%, respectively. PMID:29462204

Effect of salt-tolerant yeast of Candida versatilis and Zygosaccharomyces rouxii on the production of biogenic amines during soy sauce fermentation.

PubMed

Qi, Wei; Hou, Li-Hua; Guo, Hong-Lian; Wang, Chun-Ling; Fan, Zhen-Chuan; Liu, Jin-Fu; Cao, Xiao-Hong

2014-06-01

This study aimed to enhance and improve the quality and safety of soy sauce. In the present work, the change of biogenic amines, such as histamine, tyramine, cadaverine, spermidine, was examined by the treatment of Candida versatilis and Zygosaccharomyces rouxii, and the influence of salt-tolerant yeast on biogenic amines was analysed during the whole fermentation process. The results showed that the content of biogenic amines was elevated after yeast treatment and the content of biogenic amines was influenced by using yeast. The dominating biogenic amine in soy sauce was tyramine. At the end of fermentation, the concentrations of biogenic amines produced by Zygosaccharomyces rouxii and Candida versatilis in the soy mash were 122.71 mg kg(-1) and 69.96 mg kg(-1) . The changes of biogenic amines in high-salt liquid soy mash during fermentation process indicated that a variety of biogenic amines were increased in the fermentation ageing period, which may be due to amino acid decarboxylation to form biogenic amines by yeast decarboxylase. The fermentation period of soy sauce should be longer than 5 months because biogenic amines began to decline after this time period. © 2013 Society of Chemical Industry.

Microbial diversity and component variation in Xiaguan Tuo Tea during pile fermentation.

PubMed

Li, Haizhou; Li, Min; Yang, Xinrui; Gui, Xin; Chen, Guofeng; Chu, Jiuyun; He, Xingwang; Wang, Weitao; Han, Feng; Li, Ping

2018-01-01

Xiaguan Tuo Tea is largely consumed by the Chinese, but there is little research into the microbial diversity and component changes during the fermentation of this tea. In this study, we first used fluorescence in situ hybridization (FISH), next-generation sequencing (NGS) and chemical analysis methods to determine the microbial abundance and diversity and the chemical composition during fermentation. The FISH results showed that the total number of microorganisms ranges from 2.3×102 to 4.0×108 cells per gram of sample during fermentation and is mainly dominated by fungi. In the early fermentation stages, molds are dominant (0.6×102~2.8×106 cells/g, 0~35 d). However, in the late stages of fermentation, yeasts are dominant (3.6×104~9.6×106 cells/g, 35~56 d). The bacteria have little effect during the fermentation of tea (102~103 cells/g, <1% of fungus values). Of these fungi, A. niger (Aspergillus niger) and B. adeninivorans (Blastobotrys adeninivorans) are identified as the two most common strains, based on Next-generation Sequencing (NGS) analysis. Peak diversity in tea was observed at day 35 of fermentation (Shannon-Weaver index: 1.195857), and lower diversity was observed on days 6 and 56 of fermentation (Shannon-Weaver index 0.860589 and 1.119106, respectively). During the microbial fermentation, compared to the unfermented tea, the tea polyphenol content decreased by 54%, and the caffeine content increased by 59%. Theanine and free amino acid contents were reduced during fermentation by 81.1 and 92.85%, respectively.

Use of Selected Lactic Acid Bacteria and Quinoa Flour for Manufacturing Novel Yogurt-Like Beverages.

PubMed

Lorusso, Anna; Coda, Rossana; Montemurro, Marco; Rizzello, Carlo Giuseppe

2018-04-01

This study aimed at investigating the suitability of quinoa for making yogurt-like beverages. After the selection of the adequate technological parameters, the fermentation was carried out by using different lactic acid bacteria strains: a probiotic ( Lactobacillus rhamnosus SP1), an exopolysaccharides (EPS)-producing ( Weissella confusa DSM 20194), and one isolated from quinoa ( Lactobacillus plantarum T6B10). During the 20 h of fermentation, W. confusa caused the highest viscosity increase. All the strains had improved concentration of free amino acids and γ-Aminobutyric acid (GABA), polyphenols availability, antioxidant activity (up to 54%), and protein digestibility. The nutritional index (NI) was the highest when L. rhamnosus SP1 was used. The starch hydrolysis index in vitro ranged from 52 to 60. During storage at 4 °C, viscosity and water holding capacity decreased with the exception of the beverage fermented with W. confusa , while all the nutritional characteristics remained stable or slightly increased. Sensory analyses showed that beverages had good textural and organoleptic profiles. Besides the well-known positive properties of the raw matrix, fermentation allowed the obtainment of beverages with different features. Due to the nutritional and functional characteristics conferred to the quinoa beverages, the use of the probiotic and EPS-producing strains showed adequate potential for the industrial application.

Investigation into the misincorporation of norleucine into a recombinant protein vaccine candidate.

PubMed

Ni, Joyce; Gao, Meg; James, Andrew; Yao, Jiansheng; Yuan, Tao; Carpick, Bruce; D'Amore, Tony; Farrell, Patrick

2015-06-01

A high level of norleucine misincorporation was detected in a recombinant methionine-rich protein vaccine candidate expressed in E. coli K12. An investigation was conducted to evaluate a simple remediation strategy to reduce norleucine misincorporation and to determine if the phenomenon was either (a) due to the depletion of methionine during fermentation, (b) a result of the cultivation environment, or (c) a strain-specific effect. While supplementation with exogenous methionine improved product quality, the undesirable biosynthesis of non-standard amino acids such as norleucine and norvaline persisted. In contrast, non-standard amino acid biosynthesis was quickly minimized upon selection of an appropriate fed-batch process control strategy, fermentation medium, and nutrient feed. By expressing the same protein in E. coli BL21(DE3), it was determined that the biosynthesis of norleucine and norvaline, and the misincorporation of norleucine into the protein were primarily attributed to the use of E. coli K12 as the host for protein expression.

Management of Multiple Nitrogen Sources during Wine Fermentation by Saccharomyces cerevisiae

PubMed Central

Crépin, Lucie; Truong, Nhat My; Bloem, Audrey; Sanchez, Isabelle; Dequin, Sylvie

2017-01-01

ABSTRACT During fermentative growth in natural and industrial environments, Saccharomyces cerevisiae must redistribute the available nitrogen from multiple exogenous sources to amino acids in order to suitably fulfill anabolic requirements. To exhaustively explore the management of this complex resource, we developed an advanced strategy based on the reconciliation of data from a set of stable isotope tracer experiments with labeled nitrogen sources. Thus, quantifying the partitioning of the N compounds through the metabolism network during fermentation, we demonstrated that, contrary to the generally accepted view, only a limited fraction of most of the consumed amino acids is directly incorporated into proteins. Moreover, substantial catabolism of these molecules allows for efficient redistribution of nitrogen, supporting the operative de novo synthesis of proteinogenic amino acids. In contrast, catabolism of consumed amino acids plays a minor role in the formation of volatile compounds. Another important feature is that the α-keto acid precursors required for the de novo syntheses originate mainly from the catabolism of sugars, with a limited contribution from the anabolism of consumed amino acids. This work provides a comprehensive view of the intracellular fate of consumed nitrogen sources and the metabolic origin of proteinogenic amino acids, highlighting a strategy of distribution of metabolic fluxes implemented by yeast as a means of adapting to environments with changing and scarce nitrogen resources. IMPORTANCE A current challenge for the wine industry, in view of the extensive competition in the worldwide market, is to meet consumer expectations regarding the sensory profile of the product while ensuring an efficient fermentation process. Understanding the intracellular fate of the nitrogen sources available in grape juice is essential to the achievement of these objectives, since nitrogen utilization affects both the fermentative activity of yeasts and the formation of flavor compounds. However, little is known about how the metabolism operates when nitrogen is provided as a composite mixture, as in grape must. Here we quantitatively describe the distribution through the yeast metabolic network of the N moieties and C backbones of these nitrogen sources. Knowledge about the management of a complex resource, which is devoted to improvement of the use of the scarce N nutrient for growth, will be useful for better control of the fermentation process and the sensory quality of wines. PMID:28115380

Management of Multiple Nitrogen Sources during Wine Fermentation by Saccharomyces cerevisiae.

PubMed

Crépin, Lucie; Truong, Nhat My; Bloem, Audrey; Sanchez, Isabelle; Dequin, Sylvie; Camarasa, Carole

2017-03-01

During fermentative growth in natural and industrial environments, Saccharomyces cerevisiae must redistribute the available nitrogen from multiple exogenous sources to amino acids in order to suitably fulfill anabolic requirements. To exhaustively explore the management of this complex resource, we developed an advanced strategy based on the reconciliation of data from a set of stable isotope tracer experiments with labeled nitrogen sources. Thus, quantifying the partitioning of the N compounds through the metabolism network during fermentation, we demonstrated that, contrary to the generally accepted view, only a limited fraction of most of the consumed amino acids is directly incorporated into proteins. Moreover, substantial catabolism of these molecules allows for efficient redistribution of nitrogen, supporting the operative de novo synthesis of proteinogenic amino acids. In contrast, catabolism of consumed amino acids plays a minor role in the formation of volatile compounds. Another important feature is that the α-keto acid precursors required for the de novo syntheses originate mainly from the catabolism of sugars, with a limited contribution from the anabolism of consumed amino acids. This work provides a comprehensive view of the intracellular fate of consumed nitrogen sources and the metabolic origin of proteinogenic amino acids, highlighting a strategy of distribution of metabolic fluxes implemented by yeast as a means of adapting to environments with changing and scarce nitrogen resources. IMPORTANCE A current challenge for the wine industry, in view of the extensive competition in the worldwide market, is to meet consumer expectations regarding the sensory profile of the product while ensuring an efficient fermentation process. Understanding the intracellular fate of the nitrogen sources available in grape juice is essential to the achievement of these objectives, since nitrogen utilization affects both the fermentative activity of yeasts and the formation of flavor compounds. However, little is known about how the metabolism operates when nitrogen is provided as a composite mixture, as in grape must. Here we quantitatively describe the distribution through the yeast metabolic network of the N moieties and C backbones of these nitrogen sources. Knowledge about the management of a complex resource, which is devoted to improvement of the use of the scarce N nutrient for growth, will be useful for better control of the fermentation process and the sensory quality of wines. Copyright © 2017 American Society for Microbiology.

Effects of Schiff Base Formation and Aldol Condensation on the Determination of Aldehydes in Rice Wine Using GC-MS.

PubMed

Han, Ji Hye; Lee, Sang Mi; Kim, Young-Suk

2017-04-11

The Schiff base reaction and aldol condensation that occur during sample preparation can lead to the reduction of aldehyde content in the analysis of traditional Korean rice wine, makgeolli. The contents of aldehydes were decreased, whereas those of hydroxy carbonyl compounds were increased by increasing the pH. In the presence of added amino acids, the levels of aldehydes in makgeolli were reduced as the amount of the amino acid alanine increased. Also, the contents of hydroxyl carbonyl compounds were reduced by alanine addition as compared to the control. Therefore, the determination of aldehydes can be affected by pH and the amount of amino acids, which can vary during fermentation and storage of alcoholic beverages because pH and amino acids affect Schiff base formation and aldol condensation.

High-Throughput Metabolic Fingerprinting of Legume Silage Fermentations via Fourier Transform Infrared Spectroscopy and Chemometrics

PubMed Central

Johnson, Helen E.; Broadhurst, David; Kell, Douglas B.; Theodorou, Michael K.; Merry, Roger J.; Griffith, Gareth W.

2004-01-01

Silage quality is typically assessed by the measurement of several individual parameters, including pH, lactic acid, acetic acid, bacterial numbers, and protein content. The objective of this study was to use a holistic metabolic fingerprinting approach, combining a high-throughput microtiter plate-based fermentation system with Fourier transform infrared (FT-IR) spectroscopy, to obtain a snapshot of the sample metabolome (typically low-molecular-weight compounds) at a given time. The aim was to study the dynamics of red clover or grass silage fermentations in response to various inoculants incorporating lactic acid bacteria (LAB). The hyperspectral multivariate datasets generated by FT-IR spectroscopy are difficult to interpret visually, so chemometrics methods were used to deconvolute the data. Two-phase principal component-discriminant function analysis allowed discrimination between herbage types and different LAB inoculants and modeling of fermentation dynamics over time. Further analysis of FT-IR spectra by the use of genetic algorithms to identify the underlying biochemical differences between treatments revealed that the amide I and amide II regions (wavenumbers of 1,550 to 1,750 cm−1) of the spectra were most frequently selected (reflecting changes in proteins and free amino acids) in comparisons between control and inoculant-treated fermentations. This corresponds to the known importance of rapid fermentation for the efficient conservation of forage proteins. PMID:15006782

Use of Selected Lactic Acid Bacteria and Quinoa Flour for Manufacturing Novel Yogurt-Like Beverages

PubMed Central

Lorusso, Anna; Montemurro, Marco; Rizzello, Carlo Giuseppe

2018-01-01

This study aimed at investigating the suitability of quinoa for making yogurt-like beverages. After the selection of the adequate technological parameters, the fermentation was carried out by using different lactic acid bacteria strains: a probiotic (Lactobacillus rhamnosus SP1), an exopolysaccharides (EPS)-producing (Weissella confusa DSM 20194), and one isolated from quinoa (Lactobacillus plantarum T6B10). During the 20 h of fermentation, W. confusa caused the highest viscosity increase. All the strains had improved concentration of free amino acids and γ-Aminobutyric acid (GABA), polyphenols availability, antioxidant activity (up to 54%), and protein digestibility. The nutritional index (NI) was the highest when L. rhamnosus SP1 was used. The starch hydrolysis index in vitro ranged from 52 to 60. During storage at 4 °C, viscosity and water holding capacity decreased with the exception of the beverage fermented with W. confusa, while all the nutritional characteristics remained stable or slightly increased. Sensory analyses showed that beverages had good textural and organoleptic profiles. Besides the well-known positive properties of the raw matrix, fermentation allowed the obtainment of beverages with different features. Due to the nutritional and functional characteristics conferred to the quinoa beverages, the use of the probiotic and EPS-producing strains showed adequate potential for the industrial application. PMID:29614769

Removing a bottleneck in the Bacillus subtilis biotin pathway: bioA utilizes lysine rather than S-adenosylmethionine as the amino donor in the KAPA-to-DAPA reaction.

PubMed

Van Arsdell, Scott W; Perkins, John B; Yocum, R Rogers; Luan, Linda; Howitt, C Linda; Chatterjee, Nilu Prasad; Pero, Janice G

2005-07-05

In biotin biosynthesis, DAPA aminotransferase encoded by the bioA gene catalyzes the formation of the intermediate 7,8-diaminopelargonic acid (DAPA) from 7-keto-8-aminopelargonic acid (KAPA). DAPA aminotransferases from Escherichia coli, Serratia marcescens, and Bacillus sphaericus use S-adenosylmethionine (SAM) as the amino donor. Our observation that SAM is not an amino donor for B. subtilis DAPA aminotransferase led to a search for an alternative amino donor for this enzyme. Testing of 26 possible amino acids in a cell-free extract assay revealed that only l-lysine was able to dramatically stimulate the in vitro conversion of KAPA to DAPA by the B. subtilis DAPA aminotransferase. The K(m) for lysine and KAPA was estimated to be between 2 and 25 mM, which is significantly higher than the K(m) of purified E. coli BioA for SAM (0.15 mM). This higher requirement for lysine resulted in accumulation of KAPA during fermentation of B. subtilis biotin producing strains. However, this pathway bottleneck could be relieved by either addition of exogenous lysine to the medium or by introduction of lysine deregulated mutations into the production strains.

Saccharomyces kudriavzevii and Saccharomyces uvarum differ from Saccharomyces cerevisiae during the production of aroma-active higher alcohols and acetate esters using their amino acidic precursors.

PubMed

Stribny, Jiri; Gamero, Amparo; Pérez-Torrado, Roberto; Querol, Amparo

2015-07-16

Higher alcohols and acetate esters are important flavour and aroma components in the food industry. In alcoholic beverages these compounds are produced by yeast during fermentation. Although Saccharomyces cerevisiae is one of the most extensively used species, other species of the Saccharomyces genus have become common in fermentation processes. This study analyses and compares the production of higher alcohols and acetate esters from their amino acidic precursors in three Saccharomyces species: Saccharomyces kudriavzevii, Saccharomyces uvarum and S. cerevisiae. The global volatile compound analysis revealed that S. kudriavzevii produced large amounts of higher alcohols, whereas S. uvarum excelled in the production of acetate esters. Particularly from phenylalanine, S. uvarum produced the largest amounts of 2-phenylethyl acetate, while S. kudriavzevii obtained the greatest 2-phenylethanol formation from this precursor. The present data indicate differences in the amino acid metabolism and subsequent production of flavour-active higher alcohols and acetate esters among the closely related Saccharomyces species. This knowledge will prove useful for developing new enhanced processes in fragrance, flavour, and food industries. Copyright © 2015. Published by Elsevier B.V.

Allelic variants of hexose transporter Hxt3p and hexokinases Hxk1p/Hxk2p in strains of Saccharomyces cerevisiae and interspecies hybrids.

PubMed

Zuchowska, Magdalena; Jaenicke, Elmar; König, Helmut; Claus, Harald

2015-11-01

The transport of sugars across the plasma membrane is a critical step in the utilization of glucose and fructose by Saccharomyces cerevisiae during must fermentations. Variations in the molecular structure of hexose transporters and kinases may affect the ability of wine yeast strains to finish sugar fermentation, even under stressful wine conditions. In this context, we sequenced and compared genes encoding the hexose transporter Hxt3p and the kinases Hxk1p/Hxk2p of Saccharomyces strains and interspecies hybrids with different industrial usages and regional backgrounds. The Hxt3p primary structure varied in a small set of amino acids, which characterized robust yeast strains used for the production of sparkling wine or to restart stuck fermentations. In addition, interspecies hybrid strains, previously isolated at the end of spontaneous fermentations, revealed a common amino acid signature. The location and potential influence of the amino acids exchanges is discussed by means of a first modelled Hxt3p structure. In comparison, hexokinase genes were more conserved in different Saccharomyces strains and hybrids. Thus, molecular variants of the hexose carrier Hxt3p, but not of kinases, correlate with different fermentation performances of yeast. Copyright © 2015 John Wiley & Sons, Ltd.

Aspergillus oryzae GB-107 fermentation improves nutritional quality of food soybeans and feed soybean meals.

PubMed

Hong, Kee-Jong; Lee, Chan-Ho; Kim, Sung Woo

2004-01-01

This study evaluated the effect of fermentation on the nutritional quality of food-grade soybeans and feed-grade soybean meals. Soybeans and soybean meals were fermented by Aspergillus oryzae GB-107 in a bed-packed solid fermentor for 48 hours. After fermentation, their nutrient contents as well as trypsin inhibitor were measured and compared with those of raw soybeans and soybean meals. Proteins were extracted from fermented and non-fermented soybeans and soybean meals, and the peptide characteristics were evaluated after electrophoresis. Fermented soybeans and fermented soybean meals contained 10% more (P < .05) crude protein than raw soybeans and soybean meals. The essential amino acid profile was unchanged after fermentation. Fermentation eliminated (P < .05) most of the trypsin inhibitor from both soybeans and soybean meals. Fermentation increased the amount of small-size peptides (<20 kDa) (P < .05) compared with raw soybeans, while significantly decreasing large-size peptides (>60 kDa) (P < .05). Fermented soybean meal contained more (P < .01) small-size peptides (<20 kDa) than soybean meal. Fermented soybean meal did not contain large-size peptides (>60 kDa), whereas 22.1% of peptides in soybean meal were large-size (>60 kDa). Collectively, fermentation increased protein content, eliminated trypsin inhibitors, and reduced peptide size in soybeans and soybean meals. These effects of fermentation might make soy foods more useful in human diets as a functional food and benefit livestock as a novel feed ingredient.

Effects of Temperature on Bacterial Communities and Metabolites during Fermentation of Myeolchi-Aekjeot, a Traditional Korean Fermented Anchovy Sauce.

PubMed

Jung, Ji Young; Lee, Hyo Jung; Chun, Byung Hee; Jeon, Che Ok

2016-01-01

Myeolchi-aekjeot (MA) in Korea is produced outdoors without temperature controls, which is a major obstacle to produce commercial MA products with uniform quality. To investigate the effects of temperature on MA fermentation, pH, bacterial abundance and community, and metabolites were monitored during fermentation at 15°C, 20°C, 25°C, and 30°C. Initial pH values were approximately 6.0, and pH values increased after approximately 42 days, with faster increases at higher temperatures. Bacterial abundances increased rapidly in all MA samples after quick initial decreases during early fermentation and then they again steadily decreased after reaching their maxima, which were significantly greater at higher temperatures. Bacterial community analysis revealed that Proteobacteria and Tenericutes were predominant in all initial MA samples, but they were rapidly displaced by Firmicutes as fermentation progressed. Photobacterium and Mycoplasma belonging to Proteobacteria and Tenericutes, respectively, which may include potentially pathogenic strains, were dominant in initial MA, but decreased with the growth of Chromohalobacter, which occurred faster at higher temperatures--they were dominant until 273 and 100 days at 15°C and 20°C, respectively, but not detected after 30 days at 25°C and 30°C. Chromohalobacter also decreased with the appearance of subsequent genera belonging to Firmicutes in all MA samples. Tetragenococcus, halophilic lactic acid bacteria, appeared predominantly at 20°C, 25°C, and 30°C; they were most abundant at 30°C, but not detected at 15°C. Alkalibacillus and Lentibacillus appeared as dominant genera with the decrease of Tetragenococcus at 25°C and 30°C, but only Lentibacillus was dominant at 15°C and 20°C. Metabolite analysis showed that amino acids related to tastes were major metabolites and their concentrations were relatively higher at high temperatures. This study suggests that high temperatures (approximately 30°C) may be appropriate in MA fermentation, in the light of faster disappearance of potentially pathogenic genera, higher amino acids, growth of Tetragenococcus, and faster fermentation.

Effects of Temperature on Bacterial Communities and Metabolites during Fermentation of Myeolchi-Aekjeot, a Traditional Korean Fermented Anchovy Sauce

PubMed Central

Chun, Byung Hee; Jeon, Che Ok

2016-01-01

Myeolchi-aekjeot (MA) in Korea is produced outdoors without temperature controls, which is a major obstacle to produce commercial MA products with uniform quality. To investigate the effects of temperature on MA fermentation, pH, bacterial abundance and community, and metabolites were monitored during fermentation at 15°C, 20°C, 25°C, and 30°C. Initial pH values were approximately 6.0, and pH values increased after approximately 42 days, with faster increases at higher temperatures. Bacterial abundances increased rapidly in all MA samples after quick initial decreases during early fermentation and then they again steadily decreased after reaching their maxima, which were significantly greater at higher temperatures. Bacterial community analysis revealed that Proteobacteria and Tenericutes were predominant in all initial MA samples, but they were rapidly displaced by Firmicutes as fermentation progressed. Photobacterium and Mycoplasma belonging to Proteobacteria and Tenericutes, respectively, which may include potentially pathogenic strains, were dominant in initial MA, but decreased with the growth of Chromohalobacter, which occurred faster at higher temperatures––they were dominant until 273 and 100 days at 15°C and 20°C, respectively, but not detected after 30 days at 25°C and 30°C. Chromohalobacter also decreased with the appearance of subsequent genera belonging to Firmicutes in all MA samples. Tetragenococcus, halophilic lactic acid bacteria, appeared predominantly at 20°C, 25°C, and 30°C; they were most abundant at 30°C, but not detected at 15°C. Alkalibacillus and Lentibacillus appeared as dominant genera with the decrease of Tetragenococcus at 25°C and 30°C, but only Lentibacillus was dominant at 15°C and 20°C. Metabolite analysis showed that amino acids related to tastes were major metabolites and their concentrations were relatively higher at high temperatures. This study suggests that high temperatures (approximately 30°C) may be appropriate in MA fermentation, in the light of faster disappearance of potentially pathogenic genera, higher amino acids, growth of Tetragenococcus, and faster fermentation. PMID:26977596

Effect of propionic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

PubMed

Xu, Jian; Bao, Jia-Wei; Su, Xian-Feng; Zhang, Hong-Jian; Zeng, Xin; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

2016-03-01

In this study, an integrated citric acid-methane fermentation process was established to solve the problem of wastewater treatment in citric acid production. Citric acid wastewater was treated through anaerobic digestion and then the anaerobic digestion effluent (ADE) was further treated and recycled for the next batch citric acid fermentation. This process could eliminate wastewater discharge and reduce water resource consumption. Propionic acid was found in the ADE and its concentration continually increased in recycling. Effect of propionic acid on citric acid fermentation was investigated, and results indicated that influence of propionic acid on citric acid fermentation was contributed to the undissociated form. Citric acid fermentation was inhibited when the concentration of propionic acid was above 2, 4, and 6 mM in initial pH 4.0, 4.5 and, 5.0, respectively. However, low concentration of propionic acid could promote isomaltase activity which converted more isomaltose to available sugar, thereby increasing citric acid production. High concentration of propionic acid could influence the vitality of cell and prolong the lag phase, causing large amount of glucose still remaining in medium at the end of fermentation and decreasing citric acid production.

Lactic acid fermentation of dahlia tuber starch and waste using Lactobacillus bulgaricus: A comparative study

NASA Astrophysics Data System (ADS)

Praputri, E.; Sundari, E.; Martynis, M.; Agenta, P.

2018-03-01

Lactic acid fermentation of dahlia tuber starch and waste was performed by means of Lactobacillus bulgaricus through enzymatic hydrolysis followed by fermentation process. The effect of pH condition on lactic acid production was investigated during the process. The selected bacteria produced lactic acid after 24 hours of fermentation and the productivity was increase after 24 hours of fermentation. After 120 hours of fermentation, it was found that dahlia tuber starch can produce up to 16.18% of lactic acid, whereas lactic acid produced from dahlia tuber waste was only 0.40% at pH of 4. The lactic acid production increase significantly for pH 3.5 and 4 until 96 hours of fermentation, then slowed down. On the other hand, for pH 4.5 the lactic acid production increase until 48 hours of fermentation and then slowed down. The identification of fermentation product indicated that the lactic acid produced in this study was 16.20%, acidic, yellow and cloudy with pH 3.4 – 4.2. The density of lactic acid produced ranged between 1.21 to 1.25 gr/ml.

Changes in flavour and microbial diversity during natural fermentation of suan-cai, a traditional food made in Northeast China.

PubMed

Wu, Rina; Yu, Meiling; Liu, Xiaoyu; Meng, Lingshuai; Wang, Qianqian; Xue, Yating; Wu, Junrui; Yue, Xiqing

2015-10-15

We measured changes in the main physical and chemical properties, flavour compounds and microbial diversity in suan-cai during natural fermentation. The results showed that the pH and concentration of soluble protein initially decreased but were then maintained at a stable level; the concentration of nitrite increased in the initial fermentation stage and after reaching a peak it decreased significantly to a low level by the end of fermentation. Suan-cai was rich in 17 free amino acids. All of the free amino acids increased in concentration to different degrees, except histidine. Total free amino acids reached their highest levels in the mid-fermentation stage. The 17 volatile flavour components identified at the start of fermentation increased to 57 by the mid-fermentation stage; esters and aldehydes were in the greatest diversity and abundance, contributing most to the aroma of suan-cai. Bacteria were more abundant and diverse than fungi in suan-cai; 14 bacterial species were identified from the genera Leuconostoc, Bacillus, Pseudomonas and Lactobacillus. The predominant fungal species identified were Debaryomyces hansenii, Candida tropicalis and Penicillium expansum. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of acetic acid on citric acid fermentation in an integrated citric acid-methane fermentation process.

PubMed

Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

2014-09-01

An integrated citric acid-methane fermentation process was proposed to solve the problem of extraction wastewater in citric acid fermentation process. Extraction wastewater was treated by anaerobic digestion and then recycled for the next batch of citric acid fermentation to eliminate wastewater discharge and reduce water resource consumption. Acetic acid as an intermediate product of methane fermentation was present in anaerobic digestion effluent. In this study, the effect of acetic acid on citric acid fermentation was investigated and results showed that lower concentration of acetic acid could promote Aspergillus niger growth and citric acid production. 5-Cyano-2,3-ditolyl tetrazolium chloride (CTC) staining was used to quantify the activity of A. niger cells, and the results suggested that when acetic acid concentration was above 8 mM at initial pH 4.5, the morphology of A. niger became uneven and the part of the cells' activity was significantly reduced, thereby resulting in deceasing of citric acid production. Effects of acetic acid on citric acid fermentation, as influenced by initial pH and cell number in inocula, were also examined. The result indicated that inhibition by acetic acid increased as initial pH declined and was rarely influenced by cell number in inocula.

Comparative study on nutrient composition, phytochemical, and functional characteristics of raw, germinated, and fermented Moringa oleifera seed flour

PubMed Central

Ijarotimi, Oluwole S; Adeoti, Oluwole A; Ariyo, Oluwaseun

2013-01-01

Moringa oleifera seeds were processed as raw M. oleifera (RMO), germinated M. oleifera (GMO), and fermented M. oleifera (FMO), and were evaluated for proximate, minerals, amino acids, fatty acids, phytochemicals/antinutrients, and functional properties. Protein content of GMO (23.69 ± 0.11 g/100 g) was higher than FMO (21.15 ± 0.08 g/100 g) and that of RMO (18.86 ± 0.09 g/100 g) (P < 0.05), respectively. Energy value of FMO (465.32 ± 0.48 kcal) was higher than GMO (438.62 ± 0.12 kcal) and that of RMO (409.04 ± 1.61 kcal), respectively. Mineral contents in GMO were significantly higher in iron, sodium, potassium, magnesium, and copper, while FMO were higher in calcium, phosphorus, and magnesium, and both were significantly lower than those in RMO (P < 0.05). Total essential amino acids (TEAAs) in FMO (31.07 mg/g crude protein) were higher than in GMO (26.52 mg/g crude protein), and were higher than that in RMO (23.56 mg/g crude protein). Linoleic acid (58.79 ± 0.02–62.05 ± 0.01 g/100 g) and behenic acid (0.13 ± 0.00–0.20 ± 0.06 g/100 g) were the predominant and least fatty acids, respectively. Phytochemical/antinutrient compositions in FMO samples were significantly lower than GMO, and both were significantly lower when compared with RMO samples (P < 0.05). The bulk density (pack and loose), foaming capacity, swelling capacity, and water absorption capacity (WAC) of FMO were significantly higher than those of GMO, and there was no significant difference between GMO and RMO samples. The study established that fermentation processing methods increased the protein content, essential amino acid, and polyunsaturated fatty acid profiles, and reduced antinutrient compositions of M. oleifera seed than germination processing techniques; hence, fermentation techniques should be encouraged in processing moringa seeds in food processing. PMID:24804056

Vinegar production from post-distillation slurry deriving from rice shochu production with the addition of caproic acid-producing bacteria consortium and lactic acid bacterium.

PubMed

Yuan, Hua-Wei; Tan, Li; Chen, Hao; Sun, Zhao-Yong; Tang, Yue-Qin; Kida, Kenji

2017-12-01

To establish a zero emission process, the post-distillation slurry of a new type of rice shochu (NTRS) was used for the production of health promoting vinegar. Since the NTRS post-distillation slurry contained caproic acid and lactic acid, the effect of these two organic acids on acetic acid fermentation was first evaluated. Based on these results, Acetobacter aceti CICC 21684 was selected as a suitable strain for subsequent production of vinegar. At the laboratory scale, acetic acid fermentation of the NTRS post-distillation slurry in batch mode resulted in an acetic acid concentration of 41.9 g/L, with an initial ethanol concentration of 40 g/L, and the acetic acid concentration was improved to 44.5 g/L in fed-batch mode. Compared to the NTRS post-distillation slurry, the vinegar product had higher concentrations of free amino acids and inhibition of angiotensin I converting enzyme activity. By controlling the volumetric oxygen transfer coefficient to be similar to that of the laboratory scale production, 45 g/L of acetic acid was obtained at the pilot scale, using a 75-L fermentor with a working volume of 40 L, indicating that vinegar production can be successfully scaled up. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Microbial Diversity during Fermentation of Sweet Paste, a Chinese Traditional Seasoning, Using PCR-Denaturing Gradient Gel Electrophoresis.

PubMed

Mao, Ping; Hu, Yuanliang; Liao, Tingting; Wang, Zhaoting; Zhao, Shumiao; Liang, Yunxiang; Hu, Yongmei

2017-04-28

The aim of this study was to elucidate the changes in the microbial community and biochemical properties of a traditional sweet paste during fermentation. PCR-denaturing gradient gel electrophoresis (DGGE) analysis showed that Aspergillus oryzae was the predominant species in the koji (the fungal mixture), and the majority of the fungi isolated belonged to two Zygosaccharomyces species in the mash. The bacterial DGGE profiles revealed the presence of Bacillus subtilis during fermentation, and Lactobacillus acidipiscis, Lactobacillus pubuzihii, Lactobacillus sp., Staphylococcus kloosi, and several uncultured bacteria were also detected in the mash after 14 days of main fermentation. Additionally, during main fermentation, amino-type nitrogen and total acid increased gradually to a maximum of 6.77 ± 0.25 g/kg and 19.10 ± 0.58 g/kg (30 days) respectively, and the concentration of reducing sugar increased to 337.41 ± 3.99 g/kg (7 days). The 180-day fermented sweet paste contained 261.46 ± 19.49 g/kg reducing sugar and its pH value remained at around 4.65. This study has used the PCR-DGGE technique to demonstrate the microbial community (including bacteria and fungi) in sweet paste and provides useful information (biochemical properties) about the assessment of the quality of sweet paste throughout fermentation.

Metabolic Engineering of Clostridium cellulolyticum for Production of Isobutanol from Cellulose▿

PubMed Central

Higashide, Wendy; Li, Yongchao; Yang, Yunfeng; Liao, James C.

2011-01-01

Producing biofuels directly from cellulose, known as consolidated bioprocessing, is believed to reduce costs substantially compared to a process in which cellulose degradation and fermentation to fuel are accomplished in separate steps. Here we present a metabolic engineering example for the development of a Clostridium cellulolyticum strain for isobutanol synthesis directly from cellulose. This strategy exploits the host's natural cellulolytic activity and the amino acid biosynthesis pathway and diverts its 2-keto acid intermediates toward alcohol synthesis. Specifically, we have demonstrated the first production of isobutanol to approximately 660 mg/liter from crystalline cellulose by using this microorganism. PMID:21378054

Evidence for the bacterial origin of genes encoding fermentation enzymes of the amitochondriate protozoan parasite Entamoeba histolytica.

PubMed

Rosenthal, B; Mai, Z; Caplivski, D; Ghosh, S; de la Vega, H; Graf, T; Samuelson, J

1997-06-01

Entamoeba histolytica is an amitochondriate protozoan parasite with numerous bacterium-like fermentation enzymes including the pyruvate:ferredoxin oxidoreductase (POR), ferredoxin (FD), and alcohol dehydrogenase E (ADHE). The goal of this study was to determine whether the genes encoding these cytosolic E. histolytica fermentation enzymes might derive from a bacterium by horizontal transfer, as has previously been suggested for E. histolytica genes encoding heat shock protein 60, nicotinamide nucleotide transhydrogenase, and superoxide dismutase. In this study, the E. histolytica por gene and the adhE gene of a second amitochondriate protozoan parasite, Giardia lamblia, were sequenced, and their phylogenetic positions were estimated in relation to POR, ADHE, and FD cloned from eukaryotic and eubacterial organisms. The E. histolytica por gene encodes a 1,620-amino-acid peptide that contained conserved iron-sulfur- and thiamine pyrophosphate-binding sites. The predicted E. histolytica POR showed fewer positional identities to the POR of G. lamblia (34%) than to the POR of the enterobacterium Klebsiella pneumoniae (49%), the cyanobacterium Anabaena sp. (44%), and the protozoan Trichomonas vaginalis (46%), which targets its POR to anaerobic organelles called hydrogenosomes. Maximum-likelihood, neighbor-joining, and parsimony analyses also suggested as less likely E. histolytica POR sharing more recent common ancestry with G. lamblia POR than with POR of bacteria and the T. vaginalis hydrogenosome. The G. lamblia adhE encodes an 888-amino-acid fusion peptide with an aldehyde dehydrogenase at its amino half and an iron-dependent (class 3) ADH at its carboxy half. The predicted G. lamblia ADHE showed extensive positional identities to ADHE of Escherichia coli (49%), Clostridium acetobutylicum (44%), and E. histolytica (43%) and lesser identities to the class 3 ADH of eubacteria and yeast (19 to 36%). Phylogenetic analyses inferred a closer relationship of the E. histolytica ADHE to bacterial ADHE than to the G. lamblia ADHE. The 6-kDa FD of E. histolytica and G. lamblia were most similar to those of the archaebacterium Methanosarcina barkeri and the delta-purple bacterium Desulfovibrio desulfuricans, respectively, while the 12-kDa FD of the T. vaginalis hydrogenosome was most similar to the 12-kDa FD of gamma-purple bacterium Pseudomonas putida. E. histolytica genes (and probably G. lamblia genes) encoding fermentation enzymes therefore likely derive from bacteria by horizontal transfer, although it is not clear from which bacteria these amebic genes derive. These are the first nonorganellar fermentation enzymes of eukaryotes implicated to have derived from bacteria.

Fermentation products in the cystic fibrosis airways induce aggregation and dormancy-associated expression profiles in a CF clinical isolate of Pseudomonas aeruginosa.

PubMed

Phan, Joann; Gallagher, Tara; Oliver, Andrew; England, Whitney E; Whiteson, Katrine

2018-05-01

Pseudomonas aeruginosa is a well-known dominant opportunistic pathogen in cystic fibrosis (CF) with a wide range of metabolic capacities. However, P. aeruginosa does not colonize the airways alone, and benefits from the metabolic products of neighboring cells-especially volatile molecules that can travel between different parts of the airways easily. Here, we present a study that investigates the metabolic, gene expression profiles and phenotypic responses of a P. aeruginosa clinical isolate to fermentation products lactic acid and 2,3-butanediol, metabolites that are produced by facultative anaerobic members of the CF polymicrobial community and potential biomarkers of disease progression. Although previous studies have successfully investigated the metabolic and transcriptional profiles of P. aeruginosa, most have used common lab reference strains that may differ in important ways from clinical isolates. Using transcriptomics and metabolomics with gas chromatography time of flight mass spectrometry, we observe that fermentation products induce pyocyanin production along with the expression of genes involved in P. aeruginosa amino acid utilization, dormancy and aggregative or biofilm modes of growth. These findings have important implications for how interactions within the diverse CF microbial community influence microbial physiology, with potential clinical consequences.

In Situ Production of Exopolysaccharides during Sourdough Fermentation by Cereal and Intestinal Isolates of Lactic Acid Bacteria

PubMed Central

Tieking, Markus; Korakli, Maher; Ehrmann, Matthias A.; Gänzle, Michael G.; Vogel, Rudi F.

2003-01-01

EPS formed by lactobacilli in situ during sourdough fermentation may replace hydrocolloids currently used as texturizing, antistaling, or prebiotic additives in bread production. In this study, a screening of >100 strains of cereal-associated and intestinal lactic acid bacteria was performed for the production of exopolysaccharides (EPS) from sucrose. Fifteen strains produced fructan, and four strains produced glucan. It was remarkable that formation of glucan and fructan was most frequently found in intestinal isolates and strains of the species Lactobacillus reuteri, Lactobacillus pontis, and Lactobacillus frumenti from type II sourdoughs. By the use of PCR primers derived from conserved amino acid sequences of bacterial levansucrase genes, it was shown that 6 of the 15 fructan-producing lactobacilli and none of 20 glucan producers or EPS-negative strains carried a levansucrase gene. In sourdough fermentations, it was determined whether those strains producing EPS in MRS medium modified as described by Stolz et al. (37) and containing 100 g of sucrose liter−1 as the sole source of carbon also produce the same EPS from sucrose during sourdough fermentation in the presence of 12% sucrose. For all six EPS-producing strains evaluated in sourdough fermentations, in situ production of EPS at levels ranging from 0.5 to 2 g/kg of flour was demonstrated. Production of EPS from sucrose is a metabolic activity that is widespread among sourdough lactic acid bacteria. Thus, the use of these organisms in bread production may allow the replacement of additives. PMID:12571016

iTRAQ-based proteome profiling of Saccharomyces cerevisiae and cryotolerant species Saccharomyces uvarum and Saccharomyces kudriavzevii during low-temperature wine fermentation.

PubMed

García-Ríos, Estéfani; Querol, Amparo; Guillamón, José Manuel

2016-09-02

Temperature is one of the most important parameters to affect the duration and rate of alcoholic fermentation and final wine quality. Some species of the Saccharomyces genus have shown better adaptation at low temperature than Saccharomyces cerevisiae, which was the case of cryotolerant yeasts Saccharomyces uvarum and Saccharomyces kudriavzevii. In an attempt to detect inter-specific metabolic differences, we characterized the proteomic landscape of these cryotolerant species grown at 12°C and 28°C, which we compared with the proteome of S. cerevisiae (poorly adapted at low temperature). Our results showed that the main differences among the proteomic profiling of the three Saccharomyces strains grown at 12°C and 28°C lay in translation, glycolysis and amino acid metabolism. Our data corroborate previous transcriptomic results, which suggest that S. kudriavzevii is better adapted to grow at low temperature as a result of enhanced more efficient translation. Fitter amino acid biosynthetic pathways can also be mechanisms that better explain biomass yield in cryotolerant strains. Yet even at low temperature, S. cerevisiae is the most fermentative competitive species. A higher concentration of glycolytic and alcoholic fermentation enzymes in the S. cerevisiae strain might explain such greater fermentation activity. Temperature is one of the main relevant environmental variables that microorganisms have to cope with and it is also a key factor in some industrial processes that involve microorganisms. However, we are still far from understanding the molecular and physiological mechanisms of adaptation at low temperatures. The results obtained in this study provided a global atlas of the proteome changes triggered by temperature in three different species of the genus Saccharomyces with different degree of cryotolerance. These results would facilitate a better understanding of mechanisms for how yeast could adapt at the low temperature of growth. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of yeast assimilable nitrogen content in wine fermentations by sequential injection analysis with spectrophotometric detetection.

PubMed

Muik, Barbara; Edelmann, Andrea; Lendl, Bernhard; Ayora-Cañada, María José

2002-09-01

An automated method for measuring the primary amino acid concentration in wine fermentations by sequential injection analysis with spectrophotometric detection was developed. Isoindole-derivatives from the primary amino acid were formed by reaction with o-phthaldialdehyde and N-acetyl- L-cysteine and measured at 334 nm with respect to a baseline point at 700 nm to compensate the observed Schlieren effect. As the reaction kinetic was strongly matrix dependent the analytical readout at the final reaction equilibrium has been evaluated. Therefore four parallel reaction coils were included in the flow system to be capable of processing four samples simultaneously. Using isoleucine as the representative primary amino acid in wine fermentations a linear calibration curve from 2 to 10 mM isoleucine, corresponding to 28 to 140 mg nitrogen/L (N/L) was obtained. The coefficient of variation of the method was 1.5% at a throughput of 12 samples per hour. The developed method was successfully used to monitor two wine fermentations during alcoholic fermentation. The results were in agreement with an external reference method based on high performance liquid chromatography. A mean-t-test showed no significant differences between the two methods at a confidence level of 95%.

Impact of fermentation on nitrogenous compounds of cocoa beans (Theobroma cacao L.) from various origins.

PubMed

Hue, C; Gunata, Z; Breysse, A; Davrieux, F; Boulanger, R; Sauvage, F X

2016-02-01

Tangential filtration technique was used to separate and quantify three different fractions of nitrogenous compounds depending on their molecular size, during cocoa fermentation. On every phenotype and origin analyzed, protein profile of non-fermented samples was similar. During fermentation course, proteins get degraded with a concomitant increase in amino acids content. Peptides between 3 and 10 kDa were observed at low levels. A strong correlation between amino acids and ammonia nitrogen, a fermentation marker was found. Attention was drawn on each fraction, and enabled to point out other phenomenon occurring during fermentation. The migration of some nitrogenous compounds towards the bean shell during fermentation was demonstrated. Acetone treatment of cocoa powder prior to SDS-PAGE led to losses of nitrogenous compounds. This result gives clues on the tanning phenomenon carried out by polyphenols on nitrogenous compounds, phenomenon which increases during fermentation. Copyright © 2015. Published by Elsevier Ltd.

Characterisation of aroma profiles of commercial soy sauce by odour activity value and omission test.

PubMed

Feng, Yunzi; Su, Guowan; Zhao, Haifeng; Cai, Yu; Cui, Chun; Sun-Waterhouse, Dongxiao; Zhao, Mouming

2015-01-15

Twenty-seven commercial soy sauces produced through three different fermentation processes (high-salt liquid-state fermentation soy sauce, HLFSS; low-salt solid-state fermentation soy sauce, LSFSS; Koikuchi soy sauce, KSS) were examined to identify the aroma compounds and the effect of fermentation process on the flavour of the soy sauce was investigated. Results showed that 129 volatiles were identified, of which 41 aroma-active components were quantified. The types of odorants occurring in the three soy sauce groups were similar, although their intensities significantly differed. Many esters and phenols were found at relatively high intensities in KSS, whereas some volatile acids only occurred in LSFSS. Furthermore, 23 aroma compounds had average OAVs>1, among which 3-methylbutanal, ethyl acetate, 4-hydroxy-2-ethyl-5-methyl-3(2H)-furanone, 2-methylbutanal and 3-(methylthio)propanal exhibited the highest average OAVs (>100). In addition, omission tests verified the important contribution of the products resulting from amino acid catabolism to the characteristic aroma of soy sauce. Copyright © 2014. Published by Elsevier Ltd.

Quality improvement on half-fin anchovy (Setipinna taty) fish sauce by Psychrobacter sp. SP-1 fermentation.

PubMed

Zheng, Bin; Liu, Yu; He, Xiaoxia; Hu, Shiwei; Li, Shijie; Chen, Meiling; Jiang, Wei

2017-10-01

A method of improving fish sauce quality during fermentation was investigated. Psychrobacter sp. SP-1, a halophilic protease-producing bacterium, was isolated from fish sauce with flavor-enhancing properties and non-biogenic amine-producing activity. The performance of Psychrobacter sp. SP-1 in Setipinna taty fish sauce fermentation was investigated further. The inoculation of Psychrobacter sp. SP-1 did not significantly affect pH or NaCl concentration changes (P > 0.05), although it significantly increased total moderately halophilic microbial count, protease activity, total soluble nitrogen content and amino acid nitrogen content, and also promoted the umami taste and meaty aroma (P < 0.05). Furthermore, the inoculation of Psychrobacter sp. SP-1 significantly decreased total volatile basic nitrogen content and biogenic amines content (P < 0.05), which were regarded as harmful compounds in foods. The results of the present study demonstrate that Psychrobacter sp. SP-1 can be used as a potential starter culture for improving fish sauce quality by fermentation. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Lactic Acid Fermentation of Cactus Cladodes (Opuntia ficus-indica L.) Generates Flavonoid Derivatives with Antioxidant and Anti-Inflammatory Properties.

PubMed

Filannino, Pasquale; Cavoski, Ivana; Thlien, Nadia; Vincentini, Olimpia; De Angelis, Maria; Silano, Marco; Gobbetti, Marco; Di Cagno, Raffaella

2016-01-01

Cactus pear (Opuntia ficus-indica L.) is widely distributed in the arid and semi-arid regions throughout the world. In the last decades, the interest towards vegetative crop increased, and cladodes are exploited for nutraceutical and health-promoting properties. This study aimed at investigating the capacity of selected lactic acid bacteria to increase the antioxidant and anti-inflammatory properties of cactus cladodes pulp, with the perspective of producing a functional ingredient, dietary supplement or pharmaceutical preparation. Preliminarily, the antioxidant activity was determined through in vitro assays. Further, it was confirmed through ex vivo analysis on intestinal Caco-2/TC7 cells, and the profile of flavonoids was characterized. Cactus cladode pulp was fermented with lactic acid bacteria, which were previously selected from plant materials. Chemically acidified suspension, without bacterial inoculum and incubated under the same conditions, was used as the control. Lactobacillus plantarum CIL6, POM1 and 1MR20, Lactobacillus brevis POM2 and POM4, Lactobacillus rossiae 2LC8 and Pediococcus pentosaceus CILSWE5 were the best growing strains. Fermentation of cladode pulp with L. brevis POM2 and POM4 allowed the highest concentration of γ-amino butyric acid. Lactic acid fermentation had preservative effects (P<0.05) on the levels of vitamin C and carotenoids. Two flavonoid derivatives (kaemferol and isorhamnetin) were identified in the ethyl acetate extracts, which were considered to be the major compounds responsible for the increased radical scavenging activity. After inducing oxidative stress by IL-1β, the increased antioxidant activity (P<0.05) of fermented cladode pulp was confirmed using Caco-2/TC7 cells. Fermented cladode pulp had also immune-modulatory effects towards Caco-2 cells. Compared to the control, fermented cladode pulp exhibited a significantly (P<0.05) higher inhibition of IL-8, TNFα and prostaglandins PGE2 synthesis. The highest functional effect was found using ethyl acetate extracts. In conclusion, fermentation, especially with L. plantarum strains and L. brevis POM4, enhanced the antioxidant and immune-modulation features of cladode pulp.

Lactic Acid Fermentation of Cactus Cladodes (Opuntia ficus-indica L.) Generates Flavonoid Derivatives with Antioxidant and Anti-Inflammatory Properties

PubMed Central

Filannino, Pasquale; Cavoski, Ivana; Thlien, Nadia; Vincentini, Olimpia; De Angelis, Maria; Silano, Marco; Gobbetti, Marco; Di Cagno, Raffaella

2016-01-01

Cactus pear (Opuntia ficus-indica L.) is widely distributed in the arid and semi-arid regions throughout the world. In the last decades, the interest towards vegetative crop increased, and cladodes are exploited for nutraceutical and health-promoting properties. This study aimed at investigating the capacity of selected lactic acid bacteria to increase the antioxidant and anti-inflammatory properties of cactus cladodes pulp, with the perspective of producing a functional ingredient, dietary supplement or pharmaceutical preparation. Preliminarily, the antioxidant activity was determined through in vitro assays. Further, it was confirmed through ex vivo analysis on intestinal Caco-2/TC7 cells, and the profile of flavonoids was characterized. Cactus cladode pulp was fermented with lactic acid bacteria, which were previously selected from plant materials. Chemically acidified suspension, without bacterial inoculum and incubated under the same conditions, was used as the control. Lactobacillus plantarum CIL6, POM1 and 1MR20, Lactobacillus brevis POM2 and POM4, Lactobacillus rossiae 2LC8 and Pediococcus pentosaceus CILSWE5 were the best growing strains. Fermentation of cladode pulp with L. brevis POM2 and POM4 allowed the highest concentration of γ-amino butyric acid. Lactic acid fermentation had preservative effects (P<0.05) on the levels of vitamin C and carotenoids. Two flavonoid derivatives (kaemferol and isorhamnetin) were identified in the ethyl acetate extracts, which were considered to be the major compounds responsible for the increased radical scavenging activity. After inducing oxidative stress by IL-1β, the increased antioxidant activity (P<0.05) of fermented cladode pulp was confirmed using Caco-2/TC7 cells. Fermented cladode pulp had also immune-modulatory effects towards Caco-2 cells. Compared to the control, fermented cladode pulp exhibited a significantly (P<0.05) higher inhibition of IL-8, TNFα and prostaglandins PGE2 synthesis. The highest functional effect was found using ethyl acetate extracts. In conclusion, fermentation, especially with L. plantarum strains and L. brevis POM4, enhanced the antioxidant and immune-modulation features of cladode pulp. PMID:27023062

Membrane-integrated fermentation system for improving the optical purity of D-lactic acid produced during continuous fermentation.

PubMed

Sawai, Hideki; Na, Kyungsu; Sasaki, Nanami; Mimitsuka, Takashi; Minegishi, Shin-ichi; Henmi, Masahiro; Yamada, Katsushige; Shimizu, Sakayu; Yonehara, Tetsu

2011-01-01

This report describes the production of highly optically pure D-lactic acid by the continuous fermentation of Sporolactobacillus laevolacticus and S. inulinus, using a membrane-integrated fermentation (MFR) system. The optical purity of D-lactic acid produced by the continuous fermentation system was greater than that produced by batch fermentation; the maximum value for the optical purity of D-lactic acid reached 99.8% enantiomeric excess by continuous fermentation when S. leavolacticus was used. The volumetric productivity of the optically pure D-lactic acid was about 12 g/L/h, this being approximately 11-fold higher than that obtained by batch fermentation. An enzymatic analysis indicated that both S. laevolacticus and S. inulinus could convert L-lactic acid to D-lactic acid by isomerization after the late-log phase. These results provide evidence for an effective bio-process to produce D-lactic acid of greater optical purity than has conventionally been achieved to date.

Antioxidant and Hepatoprotective Effect of Aqueous Extract of Germinated and Fermented Mung Bean on Ethanol-Mediated Liver Damage

PubMed Central

Mohd Ali, Norlaily; Mohd Yusof, Hamidah; Long, Kamariah; Yeap, Swee Keong; Ho, Wan Yong; Beh, Boon Kee; Koh, Soo Peng; Abdullah, Mohd Puad; Alitheen, Noorjahan Banu

2013-01-01

Mung bean is a hepatoprotective agent in dietary supplements. Fermentation and germination processes are well recognized to enhance the nutritional values especially the concentration of active compounds such as amino acids and GABA of various foods. In this study, antioxidant and hepatoprotective effects of freeze-dried mung bean and amino-acid- and GABA-enriched germinated and fermented mung bean aqueous extracts were compared. Liver superoxide dismutase (SOD), malondialdehyde (MDA), ferric reducing antioxidant power (FRAP), nitric oxide (NO) levels, and serum biochemical profile such as aspartate transaminase (AST), alanine transaminase (ALT), triglycerides (TG), and cholesterol and histopathological changes were examined for the antioxidant and hepatoprotective effects of these treatments. Germinated and fermented mung bean have recorded an increase of 27.9 and 7.3 times of GABA and 8.7 and 13.2 times of amino acid improvement, respectively, as compared to normal mung bean. Besides, improvement of antioxidant levels, serum markers, and NO level associated with better histopathological evaluation indicated that these extracts could promote effective recovery from hepatocyte damage. These results suggested that freeze-dried, germinated, and fermented mung bean aqueous extracts enriched with amino acids and GABA possessed better hepatoprotective effect as compared to normal mung bean. PMID:23484140

Energy from Redox Disproportionation of Sugar Carbon Drives Biotic and Abiotic Synthesis

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1997-01-01

To identify the energy source that drives the biosynthesis of amino acids, lipids, and nucleotides from glucose, we calculated the free energy change due to redox disproportionation of the substrate carbon of: (1) 26-carbon fermentation reactions and (2) the biosynthesis of amino acids and lipids of E. coli from glucose. The free energy (cal/mmol of carbon) of these reactions was plotted as a function of the degree of redox disproportionation of carbon (disproportionative electron transfers (mmol)/mmol of carbon). The zero intercept and proportionality between energy yield and degree of redox disproportionation exhibited by this plot demonstrate that redox disproportionation is the principal energy source of these redox reactions (slope of linear fit = -10.4 cal/mmol of disproportionative electron transfers). The energy and disproportionation values of E. coli amino acid and lipid biosynthesis from glucose lie near this linear curve fit with redox disproportionation accounting for 84% and 96% (and ATP only 6% and 1%) of the total energy of amino acid and lipid biosynthesis, respectively. These observations establish that redox disproportionation of carbon, and not ATP, is the primary energy source driving amino acid and lipid biosynthesis from glucose. In contrast, we found that nucleotide biosynthesis involves very little redox disproportionation, and consequently depends almost entirely on ATP for energy. The function of sugar redox disproportionation as the major source of free energy for the biosynthesis of amino acids and lipids suggests that sugar disproportionation played a central role in the origin of metabolism, and probably the origin of life.

Two-carbon metabolites, polyphenols and vitamins influence yeast chronological life span in winemaking conditions

PubMed Central

2012-01-01

Background Viability in a non dividing state is referred to as chronological life span (CLS). Most grape juice fermentation happens when Saccharomyces cerevisiae yeast cells have stopped dividing; therefore, CLS is an important factor toward winemaking success. Results We have studied both the physical and chemical determinants influencing yeast CLS. Low pH and heat shorten the maximum wine yeast life span, while hyperosmotic shock extends it. Ethanol plays an important negative role in aging under winemaking conditions, but additional metabolites produced by fermentative metabolism, such as acetaldehyde and acetate, have also a strong impact on longevity. Grape polyphenols quercetin and resveratrol have negative impacts on CLS under winemaking conditions, an unexpected behavior for these potential anti-oxidants. We observed that quercetin inhibits alcohol and aldehyde dehydrogenase activities, and that resveratrol performs a pro-oxidant role during grape juice fermentation. Vitamins nicotinic acid and nicotinamide are precursors of NAD+, and their addition reduces mean longevity during fermentation, suggesting a metabolic unbalance negative for CLS. Moreover, vitamin mix supplementation at the end of fermentation shortens CLS and enhances cell lysis, while amino acids increase life span. Conclusions Wine S. cerevisiae strains are able to sense changes in the environmental conditions and adapt their longevity to them. Yeast death is influenced by the conditions present at the end of wine fermentation, particularly by the concentration of two-carbon metabolites produced by the fermentative metabolism, such as ethanol, acetic acid and acetaldehyde, and also by the grape juice composition, particularly its vitamin content. PMID:22873488

Energy from Redox Disproportionation of Sugar Carbon Drives Biotic and Abiotic Synthesis

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1997-01-01

To identify the energy source that drives the biosynthesis of amino acids, lipids, and nucleotides from glucose, we calculated the free energy change due to redox disproportionation of the substrate carbon of: (1) 26-carbon fermentation reactions and (2) the biosynthesis of amino acids and lipids of E. coli from glucose. The free energy (cal/mmol of carbon) of these reactions was plotted as a function of the degree of redox disproportionation of carbon (disproportionative electron transfers (mmol)/mmol of carbon). The zero intercept and proportionality between energy yield and degree of redox disproportionation exhibited by this plot demonstrate that redox disproportionation is the principal energy source of these redox reactions (slope of linear fit = -10.4 cal/mmol of disproportionative electron transfers). The energy and disproportionation values of E. coli amino acid and lipid biosynthesis from glucose lie near this linear curve fit with redox disproportionation accounting for 84% and 96% (and ATP only 6% and 1 %) of the total energy of amino acid and lipid biosynthesis, respectively. These observations establish that redox disproportionation of carbon, and not ATP, is the primary energy source driving amino acid and lipid biosynthesis from glucose. In contrast, we found that nucteotide biosynthesis involves very little redox disproportionation, and consequently depends almost entirely on ATP for energy. The function of sugar redox disproportionation as the major source of free energy for the biosynthesis of amino acids and lipids suggests that sugar disproportionation played a central role in the origin of metabolism, and probably the origin of life.

Investigations on the effect of forage source, grinding, and urea supplementation on ruminal fermentation and microbial protein flow in a semi-continuous rumen simulation system.

PubMed

Hildebrand, Bastian; Boguhn, Jeannette; Rodehutscord, Markus

2011-10-01

The objective of the present study was to compare the effect of maize silage and grass silage on microbial fermentation and protein flow in a semi-continuous rumen simulation system (Rusitec) when milling screen size (MSS) during grinding was varied. Oven-dried silages were milled through screens of 1, 4 or 9 mm pore size and incubated for 48 h in a Rusitec system. Furthermore, the effect of N supplementation to maize silage (MSS: 4 mm) was investigated and single dose vs. continuous infusion of urea-N were compared. Degradation of organic matter (OM), crude protein (CP), fibre fractions and non-structural carbohydrates (NSC) as well as short-chain fatty acid production differed significantly between forage sources. Urea-N supplementation improved the degradation of NSC, but not that of fibre fractions in maize silage. The way of urea supply had only marginal effects on fermentation characteristics. An increase in MSS, and consequently in mean feed particle size, led to an improvement in the degradation of OM, CP and NSC, but efficiency of microbial net protein synthesis (EMPS; mg microbial N flow/g degraded OM) and the microbial amino acid profile were less affected. EMPS was higher in grass silage than in maize silage and was improved by urea-N supplementation in maize silage. This study indicates that fermentation of NSC as well as EMPS during incubation of maize silage was limited by availability of NH3-N. Furthermore, an increase in MSS above 1 mm seems to improve fermentation of silages in the Rusitec system.

Growth and acid production of Lactobacillus delbrueckii ssp. bulgaricus ATCC 11842 in the fermentation of algal carcass.

PubMed

Li, C; Zhang, G F; Mao, X; Wang, J Y; Duan, C Y; Wang, Z J; Liu, L B

2016-06-01

Algal carcass is a low-value byproduct of algae after its conversion to biodiesel. Dried algal carcass is rich in protein, carbohydrate, and multiple amino acids, and it is typically well suited for growth and acid production of lactic acid bacteria. In this study, Lactobacillus delbrueckii ssp. bulgaricus ATCC 11842 was used to ferment different algal carcass media (ACM), including 2% ACM, 2% ACM with 1.9% glucose (ACM-G), and 2% ACM with 1.9% glucose and 2g/L amino acid mixture (ACM-GA). Concentrations of organic acids (lactic acid and acetic acid), acetyl-CoA, and ATP were analyzed by HPLC, and activities of lactate dehydrogenase (LDH), acetokinase (ACK), pyruvate kinase (PK), and phosphofructokinase (PFK) were determined by using a chemical approach. The growth of L. bulgaricus cells in ACM-GA was close to that in the control medium (de Man, Rogosa, and Sharpe). Lactic acid and acetic acid contents were greatly reduced when L. bulgaricus cells were grown in ACM compared with the control medium. Acetyl-CoA content varied with organic acid content and was increased in cells grown in different ACM compared with the control medium. The ATP content of L. bulgaricus cells in ACM was reduced compared with that of cells grown in the control medium. Activities of PFK and ACK of L. bulgaricus cells grown in ACM were higher and those of PK and LDH were lower compared with the control. Thus, ACM rich in nutrients may serve as an excellent substrate for growth by lactic acid bacteria, and addition of appropriate amounts of glucose and amino acids can improve growth and acid production. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Comparative study of quality characteristics of meju, a Korean soybean fermentation starter, made by soybeans germinated under dark and light conditions.

PubMed

Choi, Ung Kyu; Bajpai, Vivek K

2010-01-01

This study was conducted to evaluate the effect of dark and light conditions on the quality characteristics of whole soybean meju, a Koran soybean fermentation starter, made by germinated soybeans. The sprouting rates of soybeans under dark and light conditions after 24h were 25.6+/-1.2% and 20.5+/-1.5%, respectively and reaching to a level of 99.4+/-0.4% and 98.9+/-0.5%, respectively at 60h. The pH, moisture contents and amino-type nitrogen contents had no significant differences under dark and light conditions, however, the contents were significantly different as compared to control. Also there was a significant difference in the color change values of whole soybean meju under dark and light conditions. The compositions of total organic acids in MNG, MGD and MGL were noted to be 942.2+/-111.0, 1075+/-120.2 and 1019+/-108.1mg%, respectively. However, no significant differences were observed in free amino acid contents of MNG, MGD and MGL. It was observed that isoflavone contents were significantly differed in MGD and MGL as compared to MNG. Copyright 2009 Elsevier Ltd. All rights reserved.

Amino acids production focusing on fermentation technologies - A review.

PubMed

D'Este, Martina; Alvarado-Morales, Merlin; Angelidaki, Irini

Amino acids are attractive and promising biochemicals with market capacity requirements constantly increasing. Their applicability ranges from animal feed additives, flavour enhancers and ingredients in cosmetic to specialty nutrients in pharmaceutical and medical fields. This review gives an overview of the processes applied for amino acids production and points out the main advantages and disadvantages of each. Due to the advances made in the genetic engineering techniques, the biotechnological processes, and in particular the fermentation with the aid of strains such as Corynebacterium glutamicum or Escherichia coli, play a significant role in the industrial production of amino acids. Despite the numerous advantages of the fermentative amino acids production, the process still needs significant improvements leading to increased productivity and reduction of the production costs. Although the production processes of amino acids have been extensively investigated in previous studies, a comprehensive overview of the developments in bioprocess technology has not been reported yet. This review states the importance of the fermentation process for industrial amino acids production, underlining the strengths and the weaknesses of the process. Moreover, the potential of innovative approaches utilizing macro and microalgae or bacteria are presented. Copyright © 2017 Elsevier Inc. All rights reserved.

Engineering acidic Streptomyces rubiginosus D-xylose isomerase by rational enzyme design.

PubMed

Waltman, Mary Jo; Yang, Zamin Koo; Langan, Paul; Graham, David E; Kovalevsky, Andrey

2014-02-01

To maximize bioethanol production from lignocellulosic biomass, all sugars must be utilized. Yeast fermentation can be improved by introducing the d-xylose isomerase enzyme to convert the pentose sugar d-xylose, which cannot be fermented by Saccharomyces cerevisiae, into the fermentable ketose d-xylulose. The low activity of d-xylose isomerase, especially at the low pH required for optimal fermentation, limits its use. A rational enzyme engineering approach was undertaken, and seven amino acid positions were replaced to improve the activity of Streptomyces rubiginosus d-xylose isomerase towards its physiological substrate at pH values below 6. The active-site design was guided by mechanistic insights and the knowledge of amino acid protonation states at low pH obtained from previous joint X-ray/neutron crystallographic experiments. Tagging the enzyme with 6 or 12 histidine residues at the N-terminus resulted in a significant increase in the active-site affinity towards substrate at pH 5.8. Substituting an asparagine at position 215, which hydrogen bonded to the metal-bound Glu181 and Asp245, with an aspartate gave a variant with almost an order of magnitude lower KM than measured for the native enzyme, with a 4-fold increase in activity. Other studied variants showed similar (Asp57Asn, Glu186Gln/Asn215Asp), lower (Asp57His, Asn247Asp, Lys289His, Lys289Glu) or no (Gln256Asp, Asp287Asn, ΔAsp287) activity in acidic conditions relative to the native enzyme.

Ultrasonic Monitoring of the Progress of Lactic Acid Fermentation

NASA Astrophysics Data System (ADS)

Masuzawa, Nobuyoshi; Kimura, Akihiro; Ohdaira, Etsuzo

2003-05-01

Promotion of lactic acid fermentation by ultrasonic irradiation has been attempted. It is possible to determine the progress of fermentation and production of a curd, i.e., yoghurt and or kefir, by measuring acidity using a pH meter. However, this method is inconvenient and indirect for the evaluation of the progress of lactic acid fermentation under anaerobic condition. In this study, an ultrasonic monitoring method for evaluating the progress of lactic acid fermentation was examined.

Betaine and Beet Molasses Enhance L-Lactic Acid Production by Bacillus coagulans

PubMed Central

Xu, Ke; Xu, Ping

2014-01-01

Lactic acid is an important chemical with various industrial applications, and it can be efficiently produced by fermentation, in which Bacillus coagulans strains present excellent performance. Betaine can promote lactic acid fermentation as an effective osmoprotectant. Here, positive effect of betaine on fermentation by B. coagulans is revealed. Betaine could enhance lactic acid production by protecting l-LDH activity and cell growth from osmotic inhibition, especially under high glucose concentrations and with poor organic nitrogen nutrients. The fermentation with 0.05 g/L betaine could produce 17.9% more lactic acid compared to the fermentation without betaine. Beet molasses, which is rich in sucrose and betaine, was utilized in a co-feeding fermentation and raised the productivity by 22%. The efficient lactic acid fermentation by B. coagulans is thus developed by using betaine and beet molasses. PMID:24956474

The use of fermentation liquid of wastewater primary sedimentation sludge as supplemental carbon source for denitrification based on enhanced anaerobic fermentation.

PubMed

Liu, Feng; Tian, Yu; Ding, Yi; Li, Zhipeng

2016-11-01

Wastewater primary sedimentation sludge was prepared into fermentation liquid as denitrification carbon source, and the main components of fermentation liquid was short-chain volatile fatty acids. Meanwhile, the acetic acid and propionic acid respectively accounted for about 29.36% and 26.56% in short-chain volatile fatty acids. The performance of fermentation liquid, methanol, acetic acid, propionic acid and glucose used as sole carbon source were compared. It was found that the denitrification rate with fermentation liquid as carbon source was 0.17mgNO3(-)-N/mg mixed liquor suspended solid d, faster than that with methanol, acetic acid, and propionic acid as sole carbon source, and lower than that with glucose as sole carbon source. For the fermentation liquid as carbon source, the transient accumulation of nitrite was insignificantly under different initial total nitrogen concentration. Therefore, the use of fermentation liquid for nitrogen removal could improve denitrification rate, and reduce nitrite accumulation in denitrification process. Copyright © 2016 Elsevier Ltd. All rights reserved.

Betaine and beet molasses enhance L-lactic acid production by Bacillus coagulans.

PubMed

Xu, Ke; Xu, Ping

2014-01-01

Lactic acid is an important chemical with various industrial applications, and it can be efficiently produced by fermentation, in which Bacillus coagulans strains present excellent performance. Betaine can promote lactic acid fermentation as an effective osmoprotectant. Here, positive effect of betaine on fermentation by B. coagulans is revealed. Betaine could enhance lactic acid production by protecting l-LDH activity and cell growth from osmotic inhibition, especially under high glucose concentrations and with poor organic nitrogen nutrients. The fermentation with 0.05 g/L betaine could produce 17.9% more lactic acid compared to the fermentation without betaine. Beet molasses, which is rich in sucrose and betaine, was utilized in a co-feeding fermentation and raised the productivity by 22%. The efficient lactic acid fermentation by B. coagulans is thus developed by using betaine and beet molasses.

Coproduction of acetic acid and electricity by application of microbial fuel cell technology to vinegar fermentation.

PubMed

Tanino, Takanori; Nara, Youhei; Tsujiguchi, Takuya; Ohshima, Takayuki

2013-08-01

The coproduction of a useful material and electricity via a novel application of microbial fuel cell (MFC) technology to oxidative fermentation was investigated. We focused on vinegar production, i.e., acetic acid fermentation, as an initial and model useful material that can be produced by oxidative fermentation in combination with MFC technology. The coproduction of acetic acid and electricity by applying MFC technology was successfully demonstrated by the simultaneous progress of acetic acid fermentation and electricity generation through a series of repeated batch fermentations. Although the production rate of acetic acid was very small, it increased with the number of repeated batch fermentations that were conducted. We obtained nearly identical (73.1%) or larger (89.9%) acetic acid yields than that typically achieved by aerated fermentation (75.8%). The open-cycle voltages measured before and after fermentation increased with the total fermentation time and reached a maximum value of 0.521 V prior to the third batch fermentation. The maximum current and power densities measured in this study (19.1 μA/cm² and 2.47 μW/cm², respectively) were obtained after the second batch fermentation. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Effects of different microbes on fermenting feed for sea cucumber ( Apostichopus japonicus)

NASA Astrophysics Data System (ADS)

Jiang, Yan; Wang, Yingeng; Mai, Kangsen; Zhang, Zheng; Liao, Meijie; Rong, Xiaojun

2015-10-01

The effects of different microbes on fermenting feed for sea cucumber ( Apostichopus japonicus) were compared to select the optimal fermentation strain in this study. Saccharomgces cerevisae, Candida utilis, Bacillus subtilis and Geotrichum candidum were independently added into the experimental compound feed, while only saline was mixed with the control feed. The fermentation treatments were inoculated with 10% seed solution under the condition of 25°C and 70% water content, which lasted for 5 days to elucidate the optimal microbe strain for fermenting effect. Physicochemical indexes and sensorial characteristics were measured per day during the fermentation. The indexes included dry matter recovery (DMR), crude protein (CP), the percentage of amino acid nitrogen to total nitrogen (AA-N/tN), the percentage of ammonia nitrogen to total nitrogen (NH3-N/tN), and the ratio of fermentation strains and vibrios to the total microbes, color, smell and viscosity. The results showed that DMR, CP and AA-N/tN of the S. cerevisae group reached the highest level on day 3, but the ratio of fermentation strain was second to C. utilis group. In addition, its NH3-N/tN and the ratio of vibrios were maintained at low levels, and the sensory evaluation score including smell, color and viscosity was the highest in S. cerevisae group on day 3. Therefore, S. cerevisae could be the optimal strain for the feed fermentation for sea cucumber. This research developed a new production method of fermentation feed for sea cucumber.

Removal and recovery of inhibitory volatile fatty acids from mixed acid fermentations by conventional electrodialysis.

PubMed

Jones, Rhys Jon; Massanet-Nicolau, Jaime; Guwy, Alan; Premier, Giuliano C; Dinsdale, Richard M; Reilly, Matthew

2015-08-01

Hydrogen production during dark fermentation is inhibited by the co-production of volatile fatty acids (VFAs) such as acetic and n-butyric acid. In this study, the effectiveness of conventional electrodialysis (CED) in reducing VFA concentrations in model solutions and hydrogen fermentation broths is evaluated. This is the first time CED has been reported to remove VFAs from hydrogen fermentation broths. During 60 min of operation CED removed up to 99% of VFAs from model solutions, sucrose-fed and grass-fed hydrogen fermentation broths, containing up to 1200 mg l(-1) each of acetic acid, propionic acid, i-butyric acid, n-butyric acid, i-valeric acid, and n-valeric acid. CED's ability to remove VFAs from hydrogen fermentation broths suggests that this technology is capable of improving hydrogen yields from dark fermentation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biosynthesis of indigo using recombinant E. coli: Development of a biological system for the cost-effective production of a large volume chemical

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berry, A.; Battist, S.; Chotani, G.

1995-11-01

Cost-effective production of any large-volume chemical by fermentation requires extensive manipulation of both the production organism and the fermentation and recovery processes. We have developed a recombinant E. coli system for the production of tryptophan and several other products derived from the aromatic amino acid pathway. By linking our technology for low-cost production of tryptophan from glucose with the enzyme naphthalene dioxygenase (NDO), we have achieved an overall process for the production of indigo dye from glucose. To successfully join these two technologies, both the tryptophan pathway and NDO were extensively modified via genetic engineering. In addition, systems were developedmore » to remove deleterious by-products generated during the chemical oxidations leading to indigo formation. Low-cost fermentation processes were developed that utilized minimal-salts media containing glucose as the sole carbon source. Finally, economical recovery processes were used that preserved the environmental friendliness of the biosynthetic route to indigo.« less

21 CFR 573.500 - Condensed, extracted glutamic acid fermentation product.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Condensed, extracted glutamic acid fermentation product. 573.500 Section 573.500 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... fermentation product. Condensed, extracted glutamic acid fermentation product may be safely used in animal feed...

Manipulation of the carbon storage regulator system for metabolite remodeling and biofuel production in Escherichia coli.

PubMed

McKee, Adrienne E; Rutherford, Becky J; Chivian, Dylan C; Baidoo, Edward K; Juminaga, Darmawi; Kuo, Dwight; Benke, Peter I; Dietrich, Jeffrey A; Ma, Suzanne M; Arkin, Adam P; Petzold, Christopher J; Adams, Paul D; Keasling, Jay D; Chhabra, Swapnil R

2012-06-13

Microbial engineering strategies that elicit global metabolic perturbations have the capacity to increase organism robustness for targeted metabolite production. In particular, perturbations to regulators of cellular systems that impact glycolysis and amino acid production while simultaneously decreasing fermentation by-products such as acetate and CO(2) make ideal targets. Intriguingly, perturbation of the Carbon Storage Regulator (Csr) system has been previously implicated in large changes in central carbon metabolism in E. coli. Therefore, we hypothesized that perturbation of the Csr system through the CsrA-CsrB ribonucleoprotein complex might increase production of biofuels and their intermediates from heterologous pathways. We engaged the CsrA-CsrB ribonucleoprotein complex of E. coli via overexpression of CsrB. CsrB is a 350-nucleotide non-coding RNA that antagonizes CsrA, an RNA-binding protein that regulates translation of specific mRNA targets. By using shotgun proteomics and targeted metabolomics we established that elevation of CsrB levels leads to alterations in metabolite and protein levels in glycolysis, the TCA cycle and amino acid levels. Consequently, we show that such changes can be suitably applied to improve the production of desired compounds through the native fatty acid and heterologous n-butanol and isoprenoid pathways by up to two-fold. We also observed concomitant decreases in undesirable fermentation by-products such as acetate and CO(2). We have demonstrated that simple engineering of the RNA-based Csr global regulatory system constitutes a novel approach to obtaining pathway-independent improvements within engineered hosts. Additionally, since Csr is conserved across most prokaryotic species, this approach may also be amenable to a wide variety of production hosts.

Inhibitor tolerance of a recombinant flocculating industrial Saccharomyces cerevisiae strain during glucose and xylose co-fermentation.

PubMed

Li, Yun-Cheng; Gou, Zi-Xi; Zhang, Ying; Xia, Zi-Yuan; Tang, Yue-Qin; Kida, Kenji

Lignocellulose-derived inhibitors have negative effects on the ethanol fermentation capacity of Saccharomyces cerevisiae. In this study, the effects of eight typical inhibitors, including weak acids, furans, and phenols, on glucose and xylose co-fermentation of the recombinant xylose-fermenting flocculating industrial S. cerevisiae strain NAPX37 were evaluated by batch fermentation. Inhibition on glucose fermentation, not that on xylose fermentation, correlated with delayed cell growth. The weak acids and the phenols showed additive effects. The effect of inhibitors on glucose fermentation was as follows (from strongest to weakest): vanillin>phenol>syringaldehyde>5-HMF>furfural>levulinic acid>acetic acid>formic acid. The effect of inhibitors on xylose fermentation was as follows (from strongest to weakest): phenol>vanillin>syringaldehyde>furfural>5-HMF>formic acid>levulinic acid>acetic acid. The NAPX37 strain showed substantial tolerance to typical inhibitors and showed good fermentation characteristics, when a medium with inhibitor cocktail or rape straw hydrolysate was used. This research provides important clues for inhibitors tolerance of recombinant industrial xylose-fermenting S. cerevisiae. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Metabolite profile of koji amazake and its lactic acid fermentation product by Lactobacillus sakei UONUMA.

PubMed

Oguro, Yoshifumi; Nishiwaki, Toshikazu; Shinada, Ryota; Kobayashi, Kazuya; Kurahashi, Atsushi

2017-08-01

The koji amazake is a traditional sweet Japanese beverage. It has been consumed for over a thousand years in Japan; nonetheless, little is yet known of the ingredients in koji amazake. Therefore, this study aimed to analyze the metabolites of koji amazake using a metabolomics approach. Additionally, we reformed the flavor of koji amazake by lactic acid fermentation (LAF-amazake) using Lactobacillus sakei UONUMA, which was isolated from snow caverns. The purpose of this article is to identify the ingredients in these beverages. In LAF-amazake and koji amazake, sugars, amino acids, organic acids, and vitamin B complex were determined in the two beverages, and over 300 compounds were detected in total. Thirteen saccharides were identified including two unknown trisaccharides, and there were no differences in these between the two beverages. In LAF-amazake, lactic acid, vitamin B2 (riboflavin), B3 (nicotinic acid and nicotinamide), and B6 (pyridoxine) were significantly increased as compared to koji amazake, whereas malate and glutamine decreased. These results suggested that LAF, malolactic fermentation, and glutamine deamidation occurred simultaneously in LAF-amazake. L. sakei UONUMA strains produced these vitamins. Moreover, it was surprising that acetylcholine, a well-known neurotransmitter, was newly generated in LAF-amazake. Here, we have succeeded in reforming the flavor of koji amazake and obtained these metabolic data on the two beverages. The present study could provide useful basic information for promoting functional analyses of koji amazake and LAF-amazake for human health. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Fermentative production of high titer citric acid from corn stover feedstock after dry dilute acid pretreatment and biodetoxification.

PubMed

Zhou, Ping-Ping; Meng, Jiao; Bao, Jie

2017-01-01

The aim of this work is to study the citric acid fermentation by a robust strain Aspergillus niger SIIM M288 using corn stover feedstock after dry dilute sulfuric acid pretreatment and biodetoxification. Citric acid at 100.04g/L with the yield of 94.11% was obtained, which are comparable to the starch or sucrose based citric acid fermentation. No free wastewater was generated in the overall process from the pretreatment to citric acid fermentation. Abundant divalent metal ions as well as high titer of potassium, phosphate, and nitrogen were found in corn stover hydrolysate. Further addition of extra nutrients showed no impact on increasing citric acid formation except minimum nitrogen source was required. Various fermentation parameters were tested and only minimum regulation was required during the fermentation. This study provided a biorefining process for citric acid fermentation from lignocellulose feedstock with the maximum citric acid titer and yield. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fermentation products in the cystic fibrosis airways induce aggregation and dormancy-associated expression profiles in a CF clinical isolate of Pseudomonas aeruginosa

PubMed Central

Phan, Joann; Gallagher, Tara; Oliver, Andrew; England, Whitney E; Whiteson, Katrine

2018-01-01

Abstract Pseudomonas aeruginosa is a well-known dominant opportunistic pathogen in cystic fibrosis (CF) with a wide range of metabolic capacities. However, P. aeruginosa does not colonize the airways alone, and benefits from the metabolic products of neighboring cells—especially volatile molecules that can travel between different parts of the airways easily. Here, we present a study that investigates the metabolic, gene expression profiles and phenotypic responses of a P. aeruginosa clinical isolate to fermentation products lactic acid and 2,3-butanediol, metabolites that are produced by facultative anaerobic members of the CF polymicrobial community and potential biomarkers of disease progression. Although previous studies have successfully investigated the metabolic and transcriptional profiles of P. aeruginosa, most have used common lab reference strains that may differ in important ways from clinical isolates. Using transcriptomics and metabolomics with gas chromatography time of flight mass spectrometry, we observe that fermentation products induce pyocyanin production along with the expression of genes involved in P. aeruginosa amino acid utilization, dormancy and aggregative or biofilm modes of growth. These findings have important implications for how interactions within the diverse CF microbial community influence microbial physiology, with potential clinical consequences. PMID:29617986

Caffeic acid production by simultaneous saccharification and fermentation of kraft pulp using recombinant Escherichia coli.

PubMed

Kawaguchi, Hideo; Katsuyama, Yohei; Danyao, Du; Kahar, Prihardi; Nakamura-Tsuruta, Sachiko; Teramura, Hiroshi; Wakai, Keiko; Yoshihara, Kumiko; Minami, Hiromichi; Ogino, Chiaki; Ohnishi, Yasuo; Kondo, Ahikiko

2017-07-01

Caffeic acid (3,4-dihydroxycinnamic acid) serves as a building block for thermoplastics and a precursor for biologically active compounds and was recently produced from glucose by microbial fermentation. To produce caffeic acid from inedible cellulose, separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) reactions were compared using kraft pulp as lignocellulosic feedstock. Here, a tyrosine-overproducing Escherichia coli strain was metabolically engineered to produce caffeic acid from glucose by introducing the genes encoding a 4-hydroxyphenyllactate 3-hydroxylase (hpaBC) from Pseudomonas aeruginosa and tyrosine ammonia lyase (fevV) from Streptomyces sp. WK-5344. Using the resulting recombinant strain, the maximum yield of caffeic acid in SSF (233 mg/L) far exceeded that by SHF (37.9 mg/L). In the SSF with low cellulase loads (≤2.5 filter paper unit/g glucan), caffeic acid production was markedly increased, while almost no glucose accumulation was detected, indicating that the E. coli cells experienced glucose limitation in this culture condition. Caffeic acid yield was also negatively correlated with the glucose concentration in the fermentation medium. In SHF, the formation of by-product acetate and the accumulation of potential fermentation inhibitors increased significantly with kraft pulp hydrolysate than filter paper hydrolysate. The combination of these inhibitors had synergistic effects on caffeic acid fermentation at low concentrations. With lower loads of cellulase in SSF, less potential fermentation inhibitors (furfural, 5-hydroxymethyfurfural, and 4-hydroxylbenzoic acid) accumulated in the medium. These observations suggest that glucose limitation in SSF is crucial for improving caffeic acid yield, owing to reduced by-product formation and fermentation inhibitor accumulation.

Enhancement of gamma-aminobutyric acid (GABA) levels using an autochthonous Lactobacillus futsaii CS3 as starter culture in Thai fermented shrimp (Kung-Som).

PubMed

Sanchart, Chatthaphisuth; Rattanaporn, Onnicha; Haltrich, Dietmar; Phukpattaranont, Pimpimol; Maneerat, Suppasil

2017-08-01

Gamma-aminobutyric acid (GABA) is a non-proteinogenic amino acid, which has a variety of well-characterized beneficial physiological functions. In order to improve GABA levels and the fermentation process of Thai fermented shrimp (Kung-Som), autochthonous Lactobacillus futsaii CS3 was inoculated as a starter culture into Kung-Som, and its effects on the quality of Kung-Som were studied. The optimal conditions for GABA production in Kung-Som as obtained by response surface methodology (RSM) using a central composite design (CCD) were an inoculum size of roughly 10 7 CFU/g (X 1 ) of L. futsaii cells together with the addition of 0.5% (w/w) monosodium glutamate (MSG) (X 2 ), resulting in maximum GABA levels of 10,500 mg per kg fresh product. Under these optimized conditions, the experimental GABA content of Kung-Som with an added starter culture was up to four times higher than that of the control (without starter culture) or commercial Kung-Som products (10,120 mg/kg product). Kung-Som produced by inoculation with L. futsaii CS3 but without addition of MSG showed a considerably increased GABA content of 7790 mg/kg compared to the control. Fermentation time was reduced to less than 1 week for these samples compared to the control batches, which took up to 19 days. Polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) revealed that L. futsaii CS3 remained prominently throughout the Kung-Som fermentation, and that lactic acid bacteria (LAB) rapidly dominated the total microflora because of this inoculation with L. futsaii CS3. Kung-Som samples with starter culture were accepted as well as commercial ones by 30 panelists (p > 0.05). In conclusion, L. futsaii CS3 is a good starter culture for GABA production, resulting in, improved microbiological safety as well as reduced fermentation time.

Whole-Genome Sequence Analysis of Bombella intestini LMG 28161T, a Novel Acetic Acid Bacterium Isolated from the Crop of a Red-Tailed Bumble Bee, Bombus lapidarius.

PubMed

Li, Leilei; Illeghems, Koen; Van Kerrebroeck, Simon; Borremans, Wim; Cleenwerck, Ilse; Smagghe, Guy; De Vuyst, Luc; Vandamme, Peter

2016-01-01

The whole-genome sequence of Bombella intestini LMG 28161T, an endosymbiotic acetic acid bacterium (AAB) occurring in bumble bees, was determined to investigate the molecular mechanisms underlying its metabolic capabilities. The draft genome sequence of B. intestini LMG 28161T was 2.02 Mb. Metabolic carbohydrate pathways were in agreement with the metabolite analyses of fermentation experiments and revealed its oxidative capacity towards sucrose, D-glucose, D-fructose and D-mannitol, but not ethanol and glycerol. The results of the fermentation experiments also demonstrated that the lack of effective aeration in small-scale carbohydrate consumption experiments may be responsible for the lack of reproducibility of such results in taxonomic studies of AAB. Finally, compared to the genome sequences of its nearest phylogenetic neighbor and of three other insect associated AAB strains, the B. intestini LMG 28161T genome lost 69 orthologs and included 89 unique genes. Although many of the latter were hypothetical they also included several type IV secretion system proteins, amino acid transporter/permeases and membrane proteins which might play a role in the interaction with the bumble bee host.

Transcriptome and Proteome Expression Analysis of the Metabolism of Amino Acids by the Fungus Aspergillus oryzae in Fermented Soy Sauce

PubMed Central

Zhao, Guozhong; Yao, Yunping; Wang, Chunling; Tian, Fengwei; Liu, Xiaoming; Hou, Lihua; Yang, Zhen; Zhao, Jianxin; Zhang, Hao

2015-01-01

Amino acids comprise the majority of the flavor compounds in soy sauce. A portion of these amino acids are formed from the biosynthesis and metabolism of the fungus Aspergillus oryzae; however, the metabolic pathways leading to the formation of these amino acids in A. oryzae remain largely unknown. We sequenced the transcriptomes of A. oryzae 100-8 and A. oryzae 3.042 under similar soy sauce fermentation conditions. 2D gel electrophoresis was also used to find some differences in protein expression. We found that many amino acid hydrolases (endopeptidases, aminopeptidases, and X-pro-dipeptidyl aminopeptidase) were expressed at much higher levels (mostly greater than double) in A. oryzae 100-8 than in A. oryzae 3.042. Our results indicated that glutamate dehydrogenase may activate the metabolism of amino acids. We also found that the expression levels of some genes changed simultaneously in the metabolic pathways of tyrosine and leucine and that these conserved genes may modulate the function of the metabolic pathway. Such variation in the metabolic pathways of amino acids is important as it can significantly alter the flavor of fermented soy sauce. PMID:25945335

Overproduction of 2-phenylethanol by industrial yeasts to improve organoleptic properties of bakers' products.

PubMed

Dueñas-Sánchez, Rafael; Pérez, Ana G; Codón, Antonio C; Benítez, Tahía; Rincón, Ana María

2014-06-16

2-Phenylethanol (PEA), an important alcohol derived from phenylalanine, is involved in aroma and flavour of bakers' products. Four spontaneous mutants of an industrial bakers' yeast, V1 strain, were isolated for their resistance to p-fluoro-DL-phenylalanine (PFP), a toxic analogue of L-phenylalanine. Mutants overproduced this amino acid and showed variations in their internal pool for several other amino acids. Moreover, a rise in PEA production after growth in industrial medium (MAB) was observed in three of the mutants, although their growth and fermentative capacities were slightly impaired. However, concentration of PEA remained higher during dough fermentation and also after baking, thus improving taste and aroma in bread. Copyright © 2014 Elsevier B.V. All rights reserved.

Transcriptome and Proteome Expression Analysis of the Metabolism of Amino Acids by the Fungus Aspergillus oryzae in Fermented Soy Sauce.

PubMed

Zhao, Guozhong; Yao, Yunping; Wang, Chunling; Tian, Fengwei; Liu, Xiaoming; Hou, Lihua; Yang, Zhen; Zhao, Jianxin; Zhang, Hao; Cao, Xiaohong

2015-01-01

Amino acids comprise the majority of the flavor compounds in soy sauce. A portion of these amino acids are formed from the biosynthesis and metabolism of the fungus Aspergillus oryzae; however, the metabolic pathways leading to the formation of these amino acids in A. oryzae remain largely unknown. We sequenced the transcriptomes of A. oryzae 100-8 and A. oryzae 3.042 under similar soy sauce fermentation conditions. 2D gel electrophoresis was also used to find some differences in protein expression. We found that many amino acid hydrolases (endopeptidases, aminopeptidases, and X-pro-dipeptidyl aminopeptidase) were expressed at much higher levels (mostly greater than double) in A. oryzae 100-8 than in A. oryzae 3.042. Our results indicated that glutamate dehydrogenase may activate the metabolism of amino acids. We also found that the expression levels of some genes changed simultaneously in the metabolic pathways of tyrosine and leucine and that these conserved genes may modulate the function of the metabolic pathway. Such variation in the metabolic pathways of amino acids is important as it can significantly alter the flavor of fermented soy sauce.

Purification and characterization of two bacteriocins produced by lactic acid bacteria isolated from Mongolian airag.

PubMed

Batdorj, B; Dalgalarrondo, M; Choiset, Y; Pedroche, J; Métro, F; Prévost, H; Chobert, J-M; Haertlé, T

2006-10-01

The aim of this study was to isolate and identify bacteriocin-producing lactic acid bacteria (LAB) issued from Mongolian airag (traditional fermented mare's milk), and to purify and characterize bacteriocins produced by these LAB. Identification of the bacteria (Enterococcus durans) was carried out on the basis of its morphological, biochemical characteristics and carbohydrate fermentation profile and by API50CH kit and 16S rDNA analyses. The pH-neutral cell-free supernatant of this bacterium inhibited the growth of several Lactobacillus spp. and food-borne pathogens including Escherichia coli, Staphylococcus aureus and Listeria innocua. The antimicrobial agent (enterocin A5-11) was heat stable and was not sensitive to acid and alkaline conditions (pH 2-10), but was sensitive to several proteolytic enzymes. Its inhibitory activity was completely eliminated after treatment with proteinase K and alpha-chymotrypsin. The activity was however not completely inactivated by other proteases including trypsin and pepsin. Three-step purification procedure with high recovery yields was developed to separate two bacteriocins. The applied procedure allowed the recovery of 16% and 64% of enterocins A5-11A and A5-11B, respectively, present in the culture supernatant with purity higher than 99%. SDS-PAGE analyses revealed that enterocin A5-11 has a molecular mass of 5000 Da and mass spectrometry analyses demonstrates molecular masses of 5206 and 5218 Da for fractions A and B, respectively. Amino acid analyses of both enterocins indicated significant quantitative difference in their contents in threonine, alanine, isoleucine and leucine. Their N-termini were blocked hampering straightforward Edman degradation. Bacteriocins A5-11A and B from Ent. durans belong to the class II of bacteriocins. Judging from molecular masses, amino acid composition and spectrum of activities, bacteriocins A5-11A and B from Ent. durans show high degree of similarity with enterocins L50A and L50B isolated from Enterococcus faecium (Cintas et al. 1998, 2000) and with enterocin I produced by Ent. faecium 6T1a, a strain originally isolated from a Spanish-style green olive fermentation (Floriano et al. 1998).

Branched short-chain fatty acids modulate glucose and lipid metabolism in primary adipocytes

PubMed Central

Heimann, Emilia; Nyman, Margareta; Pålbrink, Ann-Ki; Lindkvist-Petersson, Karin; Degerman, Eva

2016-01-01

ABSTRACT Short-chain fatty acids (SCFAs), e.g. acetic acid, propionic acid and butyric acid, generated through colonic fermentation of dietary fibers, have been shown to reach the systemic circulation at micromolar concentrations. Moreover, SCFAs have been conferred anti-obesity properties in both animal models and human subjects. Branched SCFAs (BSCFAs), e.g., isobutyric and isovaleric acid, are generated by fermentation of branched amino acids, generated from undigested protein reaching colon. However, BSCFAs have been sparsely investigated when referring to effects on energy metabolism. Here we primarily investigate the effects of isobutyric acid and isovaleric acid on glucose and lipid metabolism in primary rat and human adipocytes. BSCFAs inhibited both cAMP-mediated lipolysis and insulin-stimulated de novo lipogenesis at 10 mM, whereas isobutyric acid potentiated insulin-stimulated glucose uptake by all concentrations (1, 3 and 10 mM) in rat adipocytes. For human adipocytes, only SCFAs inhibited lipolysis at 10 mM. In both in vitro models, BSCFAs and SCFAs reduced phosphorylation of hormone sensitive lipase, a rate limiting enzyme in lipolysis. In addition, BSCFAs and SCFAs, in contrast to insulin, inhibited lipolysis in the presence of wortmannin, a phosphatidylinositide 3-kinase inhibitor and OPC3911, a phosphodiesterase 3 inhibitor in rat adipocytes. Furthermore, BSCFAs and SCFAs reduced insulin-mediated phosphorylation of protein kinase B. To conclude, BSCFAs have effects on adipocyte lipid and glucose metabolism that can contribute to improved insulin sensitivity in individuals with disturbed metabolism. PMID:27994949

Evaluation of the nutritional characteristics of a finger millet based complementary food.

PubMed

Mbithi-Mwikya, Stephen; Van Camp, John; Mamiro, Peter R S; Ooghe, Wilfried; Kolsteren, Patrick; Huyghebaert, Andre

2002-05-08

Finger millet (Eleusine coracana), kidney beans (Phaseolus vulgaris), peanuts (Arachis hypogoea), and mango (Mangifera indica) were processed separately and then combined, on the basis of their amino acid scores and energy content, into a complementary food for children of weaning age. The finger millet and kidney beans were processed by germination, autoclaving, and lactic acid fermentation. A mixture containing, on a dry matter basis, 65.2, 19.1, 8.0, and 7.7% of the processed finger millet, kidney beans, peanuts, and mango, respectively, gave a composite protein with an in vitro protein digestibility of 90.2% and an amino acid chemical score of 0.84. This mixture had an energy density of 16.3 kJ.g(-1) of dry matter and a decreased antinutrient content and showed a measurable improvement in the in vitro extractability for calcium, iron, and zinc. A 33% (w/v) pap made from a mix of the processed ingredients had an energy density of 5.4 kJ.g(-1) of pap, which is sufficient to meet the energy requirements of well-nourished children of 6-24 months of age at three servings a day and at the FAO average breast-feeding frequency.

Molecular and Metabolic Adaptations of Lactococcus lactis at Near-Zero Growth Rates

PubMed Central

Ercan, Onur; Wels, Michiel; Smid, Eddy J.

2014-01-01

This paper describes the molecular and metabolic adaptations of Lactococcus lactis during the transition from a growing to a near-zero growth state by using carbon-limited retentostat cultivation. Transcriptomic analyses revealed that metabolic patterns shifted between lactic- and mixed-acid fermentations during retentostat cultivation, which appeared to be controlled at the level of transcription of the corresponding pyruvate dissipation-encoding genes. During retentostat cultivation, cells continued to consume several amino acids but also produced specific amino acids, which may derive from the conversion of glycolytic intermediates. We identify a novel motif containing CTGTCAG in the upstream regions of several genes related to amino acid conversion, which we propose to be the target site for CodY in L. lactis KF147. Finally, under extremely low carbon availability, carbon catabolite repression was progressively relieved and alternative catabolic functions were found to be highly expressed, which was confirmed by enhanced initial acidification rates on various sugars in cells obtained from near-zero-growth cultures. The present integrated transcriptome and metabolite (amino acids and previously reported fermentation end products) study provides molecular understanding of the adaptation of L. lactis to conditions supporting low growth rates and expands our earlier analysis of the quantitative physiology of this bacterium at near-zero growth rates toward gene regulation patterns involved in zero-growth adaptation. PMID:25344239

L-Lactic acid production from glycerol coupled with acetic acid metabolism by Enterococcus faecalis without carbon loss.

PubMed

Murakami, Nao; Oba, Mana; Iwamoto, Mariko; Tashiro, Yukihiro; Noguchi, Takuya; Bonkohara, Kaori; Abdel-Rahman, Mohamed Ali; Zendo, Takeshi; Shimoda, Mitsuya; Sakai, Kenji; Sonomoto, Kenji

2016-01-01

Glycerol is a by-product in the biodiesel production process and considered as one of the prospective carbon sources for microbial fermentation including lactic acid fermentation, which has received considerable interest due to its potential application. Enterococcus faecalis isolated in our laboratory produced optically pure L-lactic acid from glycerol in the presence of acetic acid. Gas chromatography-mass spectrometry analysis using [1, 2-(13)C2] acetic acid proved that the E. faecalis strain QU 11 was capable of converting acetic acid to ethanol during lactic acid fermentation of glycerol. This indicated that strain QU 11 restored the redox balance by oxidizing excess NADH though acetic acid metabolism, during ethanol production, which resulted in lactic acid production from glycerol. The effects of pH control and substrate concentration on lactic acid fermentation were also investigated. Glycerol and acetic acid concentrations of 30 g/L and 10 g/L, respectively, were expected to be appropriate for lactic acid fermentation of glycerol by strain QU 11 at a pH of 6.5. Furthermore, fed-batch fermentation with 30 g/L glycerol and 10 g/L acetic acid wholly exhibited the best performance including lactic acid production (55.3 g/L), lactic acid yield (0.991 mol-lactic acid/mol-glycerol), total yield [1.08 mol-(lactic acid and ethanol)]/mol-(glycerol and acetic acid)], and total carbon yield [1.06 C-mol-(lactic acid and ethanol)/C-mol-(glycerol and acetic acid)] of lactic acid and ethanol. In summary, the strain QU 11 successfully produced lactic acid from glycerol with acetic acid metabolism, and an efficient fermentation system was established without carbon loss. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Influence of rice straw-derived dissolved organic matter on lactic acid fermentation by Rhizopus oryzae.

PubMed

Chen, Xingxuan; Wang, Xiahui; Xue, Yiyun; Zhang, Tian-Ao; Li, Yuhao; Hu, Jiajun; Tsang, Yiu Fai; Zhang, Hongsheng; Gao, Min-Tian

2018-06-01

Rice straw can be used as carbon sources for lactic acid fermentation. However, only a small amount of lactic acid is produced even though Rhizopus oryzae can consume glucose in rice straw-derived hydrolysates. This study correlated the inhibitory effect of rice straw with rice straw-derived dissolved organic matter (DOM). Lactic acid fermentations with and without DOM were conducted to investigate the effect of DOM on lactic acid fermentation by R. oryzae. Fermentation using control medium with DOM showed a similar trend to fermentation with rice straw-derived hydrolysates, showing that DOM contained the major inhibitor of rice straw. DOM assay indicated that it mainly consisted of polyphenols and polysaccharides. The addition of polyphenols and polysaccharides derived from rice straw confirmed that lactic acid fermentation was promoted by polysaccharides and significantly inhibited by polyphenols. The removal of polyphenols also improved lactic acid production. However, the loss of polysaccharides during the removal of polyphenols resulted in low glucose consumption. This study is the first to investigate the effects of rice straw-derived DOM on lactic acid fermentation by R. oryzae. The results may provide a theoretical basis for identifying inhibitors and promoters associated with lactic acid fermentation and for establishing suitable pretreatment methods. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Effect of manganese ions on ethanol fermentation by xylose isomerase expressing Saccharomyces cerevisiae under acetic acid stress.

PubMed

Ko, Ja Kyong; Um, Youngsoon; Lee, Sun-Mi

2016-12-01

The efficient fermentation of lignocellulosic hydrolysates in the presence of inhibitors is highly desirable for bioethanol production. Among the inhibitors, acetic acid released during the pretreatment of lignocellulose negatively affects the fermentation performance of biofuel producing organisms. In this study, we evaluated the inhibitory effects of acetic acid on glucose and xylose fermentation by a high performance engineered strain of xylose utilizing Saccharomyces cerevisiae, SXA-R2P-E, harboring a xylose isomerase based pathway. The presence of acetic acid severely decreased the xylose fermentation performance of this strain. However, the acetic acid stress was alleviated by metal ion supplementation resulting in a 52% increased ethanol production rate under 2g/L of acetic acid stress. This study shows the inhibitory effect of acetic acid on an engineered isomerase-based xylose utilizing strain and suggests a simple but effective method to improve the co-fermentation performance under acetic acid stress for efficient bioethanol production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metabolomics Reveals that Dietary Ferulic Acid and Quercetin Modulate Metabolic Homeostasis in Rats.

PubMed

Zhang, Limin; Dong, Manyuan; Guangyong Xu; Yuan Tian; Tang, Huiru; Wang, Yulan

2018-02-21

Phenolic compounds ingestion has been shown to have potential preventive and therapeutic effects against various metabolic diseases such as obesity and cancer. To provide a better understanding of these potential benefit effects, we investigated the metabolic alterations in urine and feces of rat ingested ferulic acid (FA) and quercetin (Qu) using NMR-based metabolomics approach. Our results suggested that dietary FA and/or Qu significantly decreased short chain fatty acids and elevated oligosaccharides in the feces, implying that dietary FA and Qu may modulate gut microbial community with inhibition of bacterial fermentation of dietary fibers. We also found that dietary FA and/or Qu regulated several host metabolic pathways including TCA cycle and energy metabolism, bile acid, amino acid, and nucleic acid metabolism. These biological effects suggest that FA and Qu display outstanding bioavailability and bioactivity and could be used for treatment of some metabolic syndromes, such as inflammatory bowel diseases and obesity.

Draft genome sequence of Dethiosulfovibrio salsuginis DSM 21565T an anaerobic, slightly halophilic bacterium isolated from a Colombian saline spring.

PubMed

Díaz-Cárdenas, Carolina; López, Gina; Alzate-Ocampo, José David; González, Laura N; Shapiro, Nicole; Woyke, Tanja; Kyrpides, Nikos C; Restrepo, Silvia; Baena, Sandra

2017-01-01

A bacterium belonging to the phylum Synergistetes , genus Dethiosulfovibrio was isolated in 2007 from a saline spring in Colombia. Dethiosulfovibrio salsuginis USBA 82 T ( DSM 21565 T = KCTC 5659 T ) is a mesophilic, strictly anaerobic, slightly halophilic, Gram negative bacterium with a diderm cell envelope. The strain ferments peptides, amino acids and a few organic acids. Here we present the description of the complete genome sequencing and annotation of the type species Dethiosulfovibrio salsuginis USBA 82 T . The genome consisted of 2.68 Mbp with a 53.7% G + C . A total of 2609 genes were predicted and of those, 2543 were protein coding genes and 66 were RNA genes. We detected in USBA 82 T genome six Synergistetes conserved signature indels (CSIs), specific for Jonquetella, Pyramidobacter and Dethiosulfovibrio . The genome of D. salsuginis contained, as expected, genes related to amino acid transport, amino acid metabolism and thiosulfate reduction. These genes represent the major gene groups of Synergistetes , related with their phenotypic traits, and interestingly, 11.8% of the genes in the genome belonged to the amino acid fermentation COG category. In addition, we identified in the genome some ammonification genes such as nitrate reductase genes. The presence of proline operon genes could be related to de novo synthesis of proline to protect the cell in response to high osmolarity. Our bioinformatics workflow included antiSMASH and BAGEL3 which allowed us to identify bacteriocins genes in the genome.

Detoxification of Corncob Acid Hydrolysate with SAA Pretreatment and Xylitol Production by Immobilized Candida tropicalis

PubMed Central

Deng, Li-Hong; Tang, Yong; Liu, Yun

2014-01-01

Xylitol fermentation production from corncob acid hydrolysate has become an attractive and promising process. However, corncob acid hydrolysate cannot be directly used as fermentation substrate owing to various inhibitors. In this work, soaking in aqueous ammonia (SAA) pretreatment was employed to reduce the inhibitors in acid hydrolysate. After detoxification, the corncob acid hydrolysate was fermented by immobilized Candida tropicalis cell to produce xylitol. Results revealed that SAA pretreatment showed high delignification and efficient removal of acetyl group compounds without effect on cellulose and xylan content. Acetic acid was completely removed, and the content of phenolic compounds was reduced by 80%. Furthermore, kinetic behaviors of xylitol production by immobilized C. tropicalis cell were elucidated from corncob acid hydrolysate detoxified with SAA pretreatment and two-step adsorption method, respectively. The immobilized C. tropicalis cell showed higher productivity efficiency using the corncob acid hydrolysate as fermentation substrate after detoxification with SAA pretreatment than by two-step adsorption method in the five successive batch fermentation rounds. After the fifth round fermentation, about 60 g xylitol/L fermentation substrate was obtained for SAA pretreatment detoxification, while about 30 g xylitol/L fermentation substrate was obtained for two-step adsorption detoxification. PMID:25133211

Yield improvement of heterologous peptides expressed in yps1-disrupted Saccharomyces cerevisiae strains.

PubMed

Egel-Mitani; Andersen; Diers; Hach; Thim; Hastrup; Vad

2000-06-01

Heterologous protein expression levels in Saccharomyces cerevisiae fermentations are highly dependent on the susceptibility to endogenous yeast proteases. Small peptides, such as glucagon and glucagon-like-peptides (GLP-1 and GLP-2), featuring an open structure are particularly accessible for proteolytic degradation during fermentation. Therefore, homogeneous products cannot be obtained. The most sensitive residues are found at basic amino acid residues in the peptide sequence. These heterologous peptides are degraded mainly by the YPS1-encoded aspartic protease, yapsin1, when produced in the yeast. In this article, distinct degradation products were analyzed by HPLC and mass spectrometry, and high yield of the heterologous peptide production has been achieved by the disruption of the YPS1 gene (previously called YAP3). By this technique, high yield continuous fermentation of glucagon in S. cerevisiae is now possible.

Recovery of succinic acid produced by fermentation of a metabolically engineered Mannheimia succiniciproducens strain.

PubMed

Song, Hyohak; Huh, Yun Suk; Lee, Sang Yup; Hong, Won Hi; Hong, Yeon Ki

2007-12-01

There have recently been much advances in the production of succinic acid, an important four-carbon dicarboxylic acid for many industrial applications, by fermentation of several natural and engineered bacterial strains. Mannheimia succiniciproducens MBEL55E isolated from bovine rumen is able to produce succinic acid with high efficiency, but also produces acetic, formic and lactic acids just like other anaerobic succinic acid producers. We recently reported the development of an engineered M. succiniciproducens LPK7 strain which produces succinic acid as a major fermentation product while producing much reduced by-products. Having an improved succinic acid producer developed, it is equally important to develop a cost-effective downstream process for the recovery of succinic acid. In this paper, we report the development of a simpler and more efficient method for the recovery of succinic acid. For the recovery of succinic acid from the fermentation broth of LPK7 strain, a simple process composed of a single reactive extraction, vacuum distillation, and crystallization yielded highly purified succinic acid (greater than 99.5% purity, wt%) with a high yield of 67.05wt%. When the same recovery process or even multiple reactive extraction steps were applied to the fermentation broth of MBEL55E, lower purity and yield of succinic acid were obtained. These results suggest that succinic acid can be purified in a cost-effective manner by using the fermentation broth of engineered LPK7 strain, showing the importance of integrating the strain development, fermentation and downstream process for optimizing the whole processes for succinic acid production.

Production and characterization of bioactive metabolites from piezotolerant deep sea fungus Nigrospora sp. in submerged fermentation.

PubMed

Arumugam, G K; Srinivasan, S K; Joshi, G; Gopal, D; Ramalingam, K

2015-01-01

To produce and characterize bioactive metabolites from piezotolerant marine fungus Nigrospora sp. in submerged fermentation. A distinct marine strain, Nigrospora sp. NIOT has been isolated from a depth of 800 m at the Arabian Sea. The 18S rRNA and internal transcribed spacers (ITS) analysis demonstrates its close association with the genus Nigrospora. Effect of pH, temperature, salinity, carbon source and amino acids was studied to optimize the fermentation conditions. Optimal mycelia growth and secondary metabolites production were observed at 6·0-8·0 pH, 20-30°C temperature, 7·5% salinity, sucrose as carbon source and tryptophan as amino acid source. The extracellular secondary metabolites exhibited high antimicrobial activities against both gram-positive and gram-negative pathogenic bacteria with minimal inhibitory concentration (MIC) values higher than 30 μg ml(-1). Strongest cytotoxicity was observed in all cell lines tested, GI50 (growth inhibition by 50%) was calculated to be 1·35, 3·2, 0·13 and 0·35 μg ml(-1) against U937, MCF-7, A673 and Jurkat, respectively. Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) analyses of secondary metabolites confirmed the production of antimicrobial and anticancer substances. A piezotolerant fungus Nigrospora sp. NIOT isolated from deep sea environment was successfully cultured under submerged fermentation. The secondary metabolites produced from this organism showed potent antimicrobial and anticancer activities with immediate application to cosmetics and pharmaceutical industries. This is the first study exploring Nigrospora sp. from 800 m in marine environment. This deep sea fungus under optimized culture conditions effectively produced bioactive secondary metabolites such as griseofulvin, spirobenzofuran and pyrone derivatives at higher concentrations. © 2014 The Society for Applied Microbiology.

Production of D-lactic acid in a continuous membrane integrated fermentation reactor by genetically modified Saccharomyces cerevisiae: enhancement in D-lactic acid carbon yield.

PubMed

Mimitsuka, Takashi; Sawai, Kenji; Kobayashi, Koji; Tsukada, Takeshi; Takeuchi, Norihiro; Yamada, Katsushige; Ogino, Hiroyasu; Yonehara, Tetsu

2015-01-01

Poly d-lactic acid is an important polymer because it improves the thermostability of poly l-lactic acid by stereo complex formation. To demonstrate potency of continuous fermentation using a membrane-integrated fermentation reactor (MFR) system, continuous fermentation using genetically modified Saccharomyces cerevisiae which produces d-lactic acid was performed at the low pH and microaerobic conditions. d-Lactic acid continuous fermentation using the MFR system by genetically modified yeast increased production rate by 11-fold compared with batch fermentation. In addition, the carbon yield of d-lactic acid in continuous fermentation was improved to 74.6 ± 2.3% compared to 39.0 ± 1.7% with batch fermentation. This dramatic improvement in carbon yield could not be explained by a reduction in carbon consumption to form cells compared to batch fermentation. Further detailed analysis at batch fermentation revealed that the carbon yield increased to 76.8% at late stationary phase. S. cerevisiae, which exhibits the Crabtree-positive effect, demonstrated significant changes in metabolic activities at low sugar concentrations (Rossignol et al., Yeast, 20, 1369-1385, 2003). Moreover, lactate-producing S. cerevisiae requires ATP supplied not only from the glycolytic pathway but also from the TCA cycle (van Maris et al., Appl. Environ. Microbiol., 70, 2898-2905, 2004). Our finding was revealed that continuous fermentation, which can maintain the conditions of both a low sugar concentration and air supply, results in Crabtree-positive and lactate-producing S. cerevisiae for suitable conditions of d-lactic acid production with respect to redox balance and ATP generation because of releasing the yeast from the Crabtree effect. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Enhancement of l-lactic acid production via synergism in open co-fermentation of Sophora flavescens residues and food waste.

PubMed

Zheng, Jin; Gao, Ming; Wang, Qunhui; Wang, Juan; Sun, Xiaohong; Chang, Qiang; Tashiro, Yukihiro

2017-02-01

In this study, Sophora flavescens residues (SFR) were used for l-lactic acid production and were mixed with food waste (FW) to assess the effects of different compositions of SFR and FW. Positive synergistic effects of mixed substrates were achieved with co-fermentation. Co-fermentation increased the proportion of l-lactic acid by decreasing the co-products of ethanol and other organic acids. A maximum l-lactic acid concentration of 48.4g/L and l-lactic acid conversion rate of 0.904g/g total sugar were obtained through co-fermentation of SFR and FW at the optimal ratio of 1:1.5. These results were approximately 6-fold those obtained during mono-fermentation of SFR. Co-fermentation of SFR and FW provides a suitable C/N ratio and pH for effective open fermentative production of l-lactic acid. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optimisation of lactic acid fermentation for improved vinegar flavour during rosy vinegar brewing.

PubMed

Jiang, Yujian; Guo, Jianna; Li, Yudong; Lin, Sen; Wang, Li; Li, Jianrong

2010-06-01

Rosy vinegar is a well-known traditional Chinese product whose flavour is affected by its lactic acid content. In this study, Lactobacillus bacteria were employed to increase the content of lactic acid during the ethanol fermentation stage. The optimised fermentation parameters were determined as an inoculation amount of 3% (v/v), a temperature of 30 degrees C and an initial pH value of 4.0. Fermentation under these optimal conditions resulted in an alcohol degree of 6.2% (v/v), a total acidity of 49.5 g L(-1) and a lactic acid content of 4.14 g L(-1). The content of lactic acid (4.14 g L(-1)), which approached the level achieved by solid state fermentation, was 3.56-fold higher than that in vinegar fermented without lactic acid bacteria (1.16 g L(-1)). The results indicate that mixed fermentation with Lactobacillus plantarum and Saccharomyces cerevisiae strains greatly increases the lactic acid content and improves the flavour of rosy vinegar. Copyright (c) 2010 Society of Chemical Industry.

The production of aromatic alcohols in non-Saccharomyces wine yeast is modulated by nutrient availability.

PubMed

González, Beatriz; Vázquez, Jennifer; Morcillo-Parra, M Ángeles; Mas, Albert; Torija, María Jesús; Beltran, Gemma

2018-09-01

Aromatic alcohols (tryptophol, phenylethanol, tyrosol) positively contribute to organoleptic characteristics of wines, and are also described as bioactive compounds and quorum sensing molecules. These alcohols are produced by yeast during alcoholic fermentation via the Erhlich pathway, although in non-Saccharomyces this production has been poorly studied. We studied how different wine yeast species modulate the synthesis patterns of aromatic alcohol production depending on glucose, nitrogen and aromatic amino acid availability. Nitrogen limitation strongly promoted the production of aromatic alcohols in all strains, whereas low glucose generally inhibited it. Increased aromatic amino acid concentrations stimulated the production of aromatic alcohols in all of the strains and conditions tested. Thus, there was a clear association between the nutrient conditions and production of aromatic alcohols in most of the wine yeast species analysed. Additionally, the synthesis pattern of these alcohols has been evaluated for the first time in Torulaspora delbrueckii, Metschnikowia pulcherrima and Starmellera bacillaris. Copyright © 2018 Elsevier Ltd. All rights reserved.

Genome-wide identification of Saccharomyces cerevisiae genes required for tolerance to acetic acid.

PubMed

Mira, Nuno P; Palma, Margarida; Guerreiro, Joana F; Sá-Correia, Isabel

2010-10-25

Acetic acid is a byproduct of Saccharomyces cerevisiae alcoholic fermentation. Together with high concentrations of ethanol and other toxic metabolites, acetic acid may contribute to fermentation arrest and reduced ethanol productivity. This weak acid is also a present in lignocellulosic hydrolysates, a highly interesting non-feedstock substrate in industrial biotechnology. Therefore, the better understanding of the molecular mechanisms underlying S. cerevisiae tolerance to acetic acid is essential for the rational selection of optimal fermentation conditions and the engineering of more robust industrial strains to be used in processes in which yeast is explored as cell factory. The yeast genes conferring protection against acetic acid were identified in this study at a genome-wide scale, based on the screening of the EUROSCARF haploid mutant collection for susceptibility phenotypes to this weak acid (concentrations in the range 70-110 mM, at pH 4.5). Approximately 650 determinants of tolerance to acetic acid were identified. Clustering of these acetic acid-resistance genes based on their biological function indicated an enrichment of genes involved in transcription, internal pH homeostasis, carbohydrate metabolism, cell wall assembly, biogenesis of mitochondria, ribosome and vacuole, and in the sensing, signalling and uptake of various nutrients in particular iron, potassium, glucose and amino acids. A correlation between increased resistance to acetic acid and the level of potassium in the growth medium was found. The activation of the Snf1p signalling pathway, involved in yeast response to glucose starvation, is demonstrated to occur in response to acetic acid stress but no evidence was obtained supporting the acetic acid-induced inhibition of glucose uptake. Approximately 490 of the 650 determinants of tolerance to acetic acid identified in this work are implicated, for the first time, in tolerance to this weak acid. These are novel candidate genes for genetic engineering to obtain more robust yeast strains against acetic acid toxicity. Among these genes there are number of transcription factors that are documented regulators of a large percentage of the genes found to exert protection against acetic acid thus being considered interesting targets for subsequent genetic engineering. The increase of potassium concentration in the growth medium was found to improve the expression of maximal tolerance to acetic acid, consistent with the idea that the adequate manipulation of nutrient concentration of industrial growth medium can be an interesting strategy to surpass the deleterious effects of this weak acid in yeast cells.

Prediction of fermentation index of cocoa beans (Theobroma cacao L.) based on color measurement and artificial neural networks.

PubMed

León-Roque, Noemí; Abderrahim, Mohamed; Nuñez-Alejos, Luis; Arribas, Silvia M; Condezo-Hoyos, Luis

2016-12-01

Several procedures are currently used to assess fermentation index (FI) of cocoa beans (Theobroma cacao L.) for quality control. However, all of them present several drawbacks. The aim of the present work was to develop and validate a simple image based quantitative procedure, using color measurement and artificial neural network (ANNs). ANN models based on color measurements were tested to predict fermentation index (FI) of fermented cocoa beans. The RGB values were measured from surface and center region of fermented beans in images obtained by camera and desktop scanner. The FI was defined as the ratio of total free amino acids in fermented versus non-fermented samples. The ANN model that included RGB color measurement of fermented cocoa surface and R/G ratio in cocoa bean of alkaline extracts was able to predict FI with no statistical difference compared with the experimental values. Performance of the ANN model was evaluated by the coefficient of determination, Bland-Altman plot and Passing-Bablok regression analyses. Moreover, in fermented beans, total sugar content and titratable acidity showed a similar pattern to the total free amino acid predicted through the color based ANN model. The results of the present work demonstrate that the proposed ANN model can be adopted as a low-cost and in situ procedure to predict FI in fermented cocoa beans through apps developed for mobile device. Copyright © 2016 Elsevier B.V. All rights reserved.

Stillage reflux in food waste ethanol fermentation and its by-product accumulation.

PubMed

Ma, Hongzhi; Yang, Jian; Jia, Yan; Wang, Qunhui; Tashiro, Yukihiro; Sonomoto, Kenji

2016-06-01

Raw materials and pollution control are key issues for the ethanol fermentation industry. To address these concerns, food waste was selected as fermentation substrate, and stillage reflux was carried out in this study. Reflux was used seven times during fermentation. Corresponding ethanol and reducing sugar were detected. Accumulation of by-products, such as organic acid, sodium chloride, and glycerol, was investigated. Lactic acid was observed to accumulate up to 120g/L, and sodium chloride reached 0.14mol/L. Other by-products did not accumulate. The first five cycles of reflux increased ethanol concentration, which prolonged fermentation time. Further increases in reflux time negatively influenced ethanol fermentation. Single-factor analysis with lactic acid and sodium chloride demonstrated that both factors affected ethanol fermentation, but lactic acid induced more effects. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lactic acid bacteria contribution to gut microbiota complexity: lights and shadows

PubMed Central

Pessione, Enrica

2012-01-01

Lactic Acid Bacteria (LAB) are ancient organisms that cannot biosynthesize functional cytochromes, and cannot get ATP from respiration. Besides sugar fermentation, they evolved electrogenic decarboxylations and ATP-forming deiminations. The right balance between sugar fermentation and decarboxylation/deimination ensures buffered environments thus enabling LAB to survive in human gastric trait and colonize gut. A complex molecular cross-talk between LAB and host exists. LAB moonlight proteins are made in response to gut stimuli and promote bacterial adhesion to mucosa and stimulate immune cells. Similarly, when LAB are present, human enterocytes activate specific gene expression of specific genes only. Furthermore, LAB antagonistic relationships with other microorganisms constitute the basis for their anti-infective role. Histamine and tyramine are LAB bioactive catabolites that act on the CNS, causing hypertension and allergies. Nevertheless, some LAB biosynthesize both gamma-amino-butyrate (GABA), that has relaxing effect on gut smooth muscles, and beta-phenylethylamine, that controls satiety and mood. Since LAB have reduced amino acid biosynthetic abilities, they developed a sophisticated proteolytic system, that is also involved in antihypertensive and opiod peptide generation from milk proteins. Short-chain fatty acids are glycolytic and phosphoketolase end-products, regulating epithelial cell proliferation and differentiation. Nevertheless, they constitute a supplementary energy source for the host, causing weight gain. Human metabolism can also be affected by anabolic LAB products such as conjugated linoleic acids (CLA). Some CLA isomers reduce cancer cell viability and ameliorate insulin resistance, while others lower the HDL/LDL ratio and modify eicosanoid production, with detrimental health effects. A further appreciated LAB feature is the ability to fix selenium into seleno-cysteine. Thus, opening interesting perspectives for their utilization as antioxidant nutraceutical vectors. PMID:22919677

Consensus pan-genome assembly of the specialised wine bacterium Oenococcus oeni.

PubMed

Sternes, Peter R; Borneman, Anthony R

2016-04-27

Oenococcus oeni is a lactic acid bacterium that is specialised for growth in the ecological niche of wine, where it is noted for its ability to perform the secondary, malolactic fermentation that is often required for many types of wine. Expanding the understanding of strain-dependent genetic variations in its small and streamlined genome is important for realising its full potential in industrial fermentation processes. Whole genome comparison was performed on 191 strains of O. oeni; from this rich source of genomic information consensus pan-genome assemblies of the invariant (core) and variable (flexible) regions of this organism were established. Genetic variation in amino acid biosynthesis and sugar transport and utilisation was found to be common between strains. Furthermore, we characterised previously-unreported intra-specific genetic variations in the natural competence of this microbe. By assembling a consensus pan-genome from a large number of strains, this study provides a tool for researchers to readily compare protein-coding genes across strains and infer functional relationships between genes in conserved syntenic regions. This establishes a foundation for further genetic, and thus phenotypic, research of this industrially-important species.

Manipulation of the carbon storage regulator system for metabolite remodeling and biofuel production in Escherichia coli

PubMed Central

2012-01-01

Background Microbial engineering strategies that elicit global metabolic perturbations have the capacity to increase organism robustness for targeted metabolite production. In particular, perturbations to regulators of cellular systems that impact glycolysis and amino acid production while simultaneously decreasing fermentation by-products such as acetate and CO2 make ideal targets. Intriguingly, perturbation of the Carbon Storage Regulator (Csr) system has been previously implicated in large changes in central carbon metabolism in E. coli. Therefore, we hypothesized that perturbation of the Csr system through the CsrA-CsrB ribonucleoprotein complex might increase production of biofuels and their intermediates from heterologous pathways. Results We engaged the CsrA-CsrB ribonucleoprotein complex of E. coli via overexpression of CsrB. CsrB is a 350-nucleotide non-coding RNA that antagonizes CsrA, an RNA-binding protein that regulates translation of specific mRNA targets. By using shotgun proteomics and targeted metabolomics we established that elevation of CsrB levels leads to alterations in metabolite and protein levels in glycolysis, the TCA cycle and amino acid levels. Consequently, we show that such changes can be suitably applied to improve the production of desired compounds through the native fatty acid and heterologous n-butanol and isoprenoid pathways by up to two-fold. We also observed concomitant decreases in undesirable fermentation by-products such as acetate and CO2. Conclusions We have demonstrated that simple engineering of the RNA-based Csr global regulatory system constitutes a novel approach to obtaining pathway-independent improvements within engineered hosts. Additionally, since Csr is conserved across most prokaryotic species, this approach may also be amenable to a wide variety of production hosts. PMID:22694848

Making soy sauce from defatted soybean meal without the mejus process by submerged cultivation using thermophilic bacteria.

PubMed

Hur, Jeong Min; Park, Doo Hyun

2015-08-01

The diversity of thermophilic bacteria was not significantly altered while growing in a defatted soybean meal (DFSM) slurry at 60 °C for 10, 20, and 30 days. Five species of thermophilic bacteria, which belong to the genera Aeribacillus (temperature gradient gel electrophoresis [TGGE] band no. 1), Saccharococcus (TGGE band no. 2), Geobacillus (TGGE band no. 3), Bacillus (TGGE band no. 4), and Anoxybacillus (TGGE band no. 5), were detected in the fermenting DFSM slurry. The cell-free culture fluid obtained from the fermenting DFSM slurry on day 14 hydrolyzed starch and soy protein at 60 °C but not at 30 °C. Soy sauce (test soy sauce) was prepared from the fermented DFSM slurry after a 30 day cultivation at 60 °C and a 60 day ripening at 45 °C. Free amino acid (AA) and organic acid contents in the soy sauce increased in proportion to the fermentation period, whereas ammonium decreased proportionally. Mg and Ca contained in the soy sauce decreased proportionally during fermentation and were lower than those in the non-fermented DFSM extract (control). Spectral absorbance of soy sauce prepared from the fermented DFSM slurry was maximal at 430 nm and increased slightly in proportion to the fermentation period. The aroma and flavor of the test soy sauce were significantly different from those of traditional Korean soy sauce. Conclusively, soy sauce may be prepared directly from the fermented DFSM slurry without meju-preparing process and fermentation period may be a factor for control of soy sauce quality.

Effects of different fermentation methods on bacterial cellulose and acid production by Gluconacetobacter xylinus in Cantonese-style rice vinegar.

PubMed

Fu, Liang; Chen, Siqian; Yi, Jiulong; Hou, Zongxia

2014-07-01

A strain of acidogenic bacterium was isolated from the fermentation liquid of Cantonese-style rice vinegar produced by traditional surface fermentation. 16S rDNA identification confirmed the bacterium as Gluconacetobacter xylinus, which synthesizes bacterial cellulose, and the acid productivity of the strain was investigated. In the study, the effects of the membrane integrity and the comparison of the air-liquid interface membrane with immerged membrane on total acidity, cellulose production, alcohol dehydrogenase (ADH) activity and number of bacteria were investigated. The cellulose membrane and the bacteria were observed under SEM for discussing their relationship. The correlations between oxygen consumption and total acid production rate were compared in surface and shake flask fermentation. The results showed the average acid productivity of the strain was 0.02g/(100mL/h), and the integrity of cellulose membrane in surface fermentation had an important effect on total acidity and cellulose production. With a higher membrane integrity, the total acidity after 144 h of fermentation was 3.75 g/100 mL, and the cellulose production was 1.71 g/100 mL after 360 h of fermentation. However, when the membrane was crushed by mechanical force, the total acidity and the cellulose production were as low as 0.36 g/100 mL and 0.14 g/100 mL, respectively. When the cellulose membrane was forced under the surface of fermentation liquid, the total acid production rate was extremely low, but the activity of ADH in the cellulose membrane was basically the same with the one above the liquid surface. The bacteria were mainly distributed in the cellulose membrane during the fermentation. The bacterial counts in surface fermentation were more than in the shake flask fermentation and G. xylinus consumed the substrate faster, in surface fermentation than in shake flask fermentation. The oxygen consumption rate and total acid production rate of surface fermentation were respectively 26.13 times and 2.92 times that of shake flask fermentation.

High-efficiency l-lactic acid production by Rhizopus oryzae using a novel modified one-step fermentation strategy.

PubMed

Fu, Yong-Qian; Yin, Long-Fei; Zhu, Hua-Yue; Jiang, Ru

2016-10-01

In this study, lactic acid fermentation by Rhizopus oryzae was investigated using the two different fermentation strategies of one-step fermentation (OSF) and conventional fermentation (CF). Compared to CF, OSF reduced the demurrage of the production process and increased the production of lactic acid. However, the qp was significantly lower than during CF. Based on analysis of μ, qs and qp, a novel modified OSF strategy was proposed. This strategy aimed to achieve a high final concentration of lactic acid, and a high qp by R. oryzae. In this strategy, the maximum lactic acid concentration and productivity of the lactic acid production stage reached 158g/l and 5.45g/(lh), which were 177% and 366% higher, respectively, than the best results from CF. Importantly, the qp and yield did not decrease. This strategy is a convenient and economical method for l-lactic acid fermentation by R. oryzae. Copyright © 2016 Elsevier Ltd. All rights reserved.

Human proinsulin C-peptide from a precursor overexpressed in Pichia pastoris.

PubMed

Huang, Yang-Bin; Li, Jiang; Gao, Xin; Sun, Jiu-Ru; Lu, Yi; Feng, Tao; Fei, Jian; Cui, Da-Fu; Xia, Qi-Chang; Ren, Jun; Zhang, You-Shang

2006-08-01

In this article we report the production of human proinsulin C-peptide with 31 amino acid residues from a precursor overexpressed in Pichia pastoris. A C-peptide precursor expression plasmid containing nine C-peptide genes in tandem was constructed and used to transform P. pastoris. Transformants with a high copy number of the C-peptide precursor gene integrated into the chromosome of P. pastoris were selected. In high-density fermentation in a 300 liter fermentor using a simple culture medium composed mainly of salt and methanol, the C-peptide precursor was overexpressed to a level of 2.28 g per liter. A simple procedure was established to purify the expression product from the culture medium. The purified C-peptide precursor was converted into C-peptide by trypsin and carboxypeptidase B joint digestion. The yield of C-peptide with a purity of 96% was 730 mg per liter of culture. The purified C-peptide was characterized by mass spectrometry, N- and C-terminal amino acid sequencing, and sodium dodecylsulfate-polyacrylamide gel electrophoresis.

Furaldehyde substrate specificity and kinetics of Saccharomyces cerevisiae alcohol dehydrogenase 1 variants.

PubMed

Laadan, Boaz; Wallace-Salinas, Valeria; Carlsson, Åsa Janfalk; Almeida, João Rm; Rådström, Peter; Gorwa-Grauslund, Marie F

2014-08-09

A previously discovered mutant of Saccharomyces cerevisiae alcohol dehydrogenase 1 (Adh1p) was shown to enable a unique NADH-dependent reduction of 5-hydroxymethylfurfural (HMF), a well-known inhibitor of yeast fermentation. In the present study, site-directed mutagenesis of both native and mutated ADH1 genes was performed in order to identify the key amino acids involved in this substrate shift, resulting in Adh1p-variants with different substrate specificities. In vitro activities of the Adh1p-variants using two furaldehydes, HMF and furfural, revealed that HMF reduction ability could be acquired after a single amino acid substitution (Y295C). The highest activity, however, was reached with the double mutation S110P Y295C. Kinetic characterization with both aldehydes and the in vivo primary substrate acetaldehyde also enabled to correlate the alterations in substrate affinity with the different amino acid substitutions. We demonstrated the key role of Y295C mutation in HMF reduction by Adh1p. We generated and kinetically characterized a group of protein variants using two furaldehyde compounds of industrial relevance. Also, we showed that there is a threshold after which higher in vitro HMF reduction activities do not correlate any more with faster in vivo rates of HMF conversion, indicating other cell limitations in the conversion of HMF.

Evolution of free amino acids, biogenic amines and n-nitrosoamines throughout ageing in organic fermented beef.

PubMed

Wójciak, Karolina M; Solska, Elżbieta

2016-01-01

In recent years, interest in uncured meat products has grown and studies were carried out on the use of substances which could replace nitrites, such as acid whey. In spite of this problem in fermented meat products, there is no information regarding the effects of prolonged ageing on the formation of chemical (nitrosoamines, biogenic amines, secondary lipid oxidation products) and microbiological (L. monocytogenes, S. aureus, OLD) toxicants in fermented beef marinated with acid whey. The aim of this study was to determine the selected pathogenic bacteria, biogenic amines, N-nitrosamines contents in fermented beef subjected to extended ageing. In this study, selected pathogenic bacteria, N-nitrosamines, biogenic amines, amino acids, TBARS values changes during the ageing of fermented beef marinated with acid whey were analyzed in 0-, 2- and 36-month-old samples. The pH values of fermented beef aged for 2 months (5.68, 5.49 and 5.68 respectively) were significantly lower (p < 0.05) than those obtained after the end of the manufacturing ripening period (5.96, 5.97 and 5.74 respectively), which confirmed the effectiveness of the fermentation process of acidification on beef. The high Lactic Acid Bacteria content (5.64-6.30 log cfu/g) confirmed this finding. Histamine was not detected in either of the products. The highest concentration of total biogenic amine (i.e. 1159.0 mg/kg) was found in fermented beef marinated with acid whey, whereas a total of only 209.8 mg/kg, was observed in control beef with nitrate and nitrite. N-nitrosamines were not detected in any of the ageing beef samples. In this study, marinating beef in acid whey did not inhibit the production of biogenic amines in the samples analyzed. The high concentration of FAAs, the potential precursor of BA, could lead to intense peptidase activity. The results obtained indicate that biogenic amines are not direct precursors for nitrosamines formation in fermented beef. The LAB strain from acid whey reduced the pH value during the first stages of ageing and ensured the microbiological safety of the product not only in the first stage of fermentation but also at the end of ageing (36 months).

Batch and fed-batch production of butyric acid by Clostridium butyricum ZJUCB

PubMed Central

He, Guo-qing; Kong, Qing; Chen, Qi-he; Ruan, Hui

2005-01-01

The production of butyric acid by Clostridium butyricum ZJUCB at various pH values was investigated. In order to study the effect of pH on cell growth, butyric acid biosynthesis and reducing sugar consumption, different cultivation pH values ranging from 6.0 to 7.5 were evaluated in 5-L bioreactor. In controlled pH batch fermentation, the optimum pH for cell growth and butyric acid production was 6.5 with a cell yield of 3.65 g/L and butyric acid yield of 12.25 g/L. Based on these results, this study then compared batch and fed-batch fermentation of butyric acid production at pH 6.5. Maximum value (16.74 g/L) of butyric acid concentration was obtained in fed-batch fermentation compared to 12.25 g/L in batch fermentation. It was concluded that cultivation under fed-batch fermentation mode could enhance butyric acid production significantly (P<0.01) by C. butyricum ZJUCB. PMID:16252341

Alcoholic fermentation induces melatonin synthesis in orange juice.

PubMed

Fernández-Pachón, M S; Medina, S; Herrero-Martín, G; Cerrillo, I; Berná, G; Escudero-López, B; Ferreres, F; Martín, F; García-Parrilla, M C; Gil-Izquierdo, A

2014-01-01

Melatonin (N-acetyl-5-methoxytryptamine) is a molecule implicated in multiple biological functions. Its level decreases with age, and the intake of foods rich in melatonin has been considered an exogenous source of this important agent. Orange is a natural source of melatonin. Melatonin synthesis occurs during alcoholic fermentation of grapes, malt and pomegranate. The amino acid tryptophan is the precursor of all 5-methoxytryptamines. Indeed, melatonin appears in a shorter time in wines when tryptophan is added before fermentation. The aim of the study was to measure melatonin content during alcoholic fermentation of orange juice and to evaluate the role of the precursor tryptophan. Identification and quantification of melatonin during the alcoholic fermentation of orange juice was carried out by UHPLC-QqQ-MS/MS. Melatonin significantly increased throughout fermentation from day 0 (3.15 ng/mL) until day 15 (21.80 ng/mL) reaching larger amounts with respect to other foods. Melatonin isomer was also analysed, but its content remained stable ranging from 11.59 to 14.18 ng/mL. The enhancement of melatonin occurred mainly in the soluble fraction. Tryptophan levels significantly dropped from 13.80 mg/L (day 0) up to 3.19 mg/L (day 15) during fermentation. Melatonin was inversely and significantly correlated with tryptophan (r = 0.907). Therefore, the enhancement in melatonin could be due to both the occurrence of tryptophan and the new synthesis by yeast. In summary, the enhancement of melatonin in novel fermented orange beverage would improve the health benefits of orange juice by increasing this bioactive compound. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The amino-terminal tail of Hxt11 confers membrane stability to the Hxt2 sugar transporter and improves xylose fermentation in the presence of acetic acid.

PubMed

Shin, Hyun Yong; Nijland, Jeroen G; de Waal, Paul P; Driessen, Arnold J M

2017-09-01

Hxt2 is a glucose repressed, high affinity glucose transporter of the yeast Saccharomyces cerevisiae and is subjected to high glucose induced degradation. Hxt11 is a sugar transporter that is stably expressed at the membrane irrespective the sugar concentration. To transfer this property to Hxt2, the N-terminal tail of Hxt2 was replaced by the corresponding region of Hxt11 yielding a chimeric Hxt11/2 transporter. This resulted in the stable expression of Hxt2 at the membrane and improved the growth on 8% d-glucose and 4% d-xylose. Mutation of N361 of Hxt11/2 into threonine reversed the specificity for d-xylose over d-glucose with high d-xylose transport rates. This mutant supported efficient sugar fermentation of both d-glucose and d-xylose at industrially relevant sugar concentrations even in the presence of the inhibitor acetic acid which is normally present in lignocellulosic hydrolysates. Biotechnol. Bioeng. 2017;114: 1937-1945. © 2017 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc. © 2017 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc.

Acetic acid fermentation of acetobacter pasteurianus: relationship between acetic acid resistance and pellicle polysaccharide formation.

PubMed

Kanchanarach, Watchara; Theeragool, Gunjana; Inoue, Taketo; Yakushi, Toshiharu; Adachi, Osao; Matsushita, Kazunobu

2010-01-01

Acetobacter pasteurianus strains IFO3283, SKU1108, and MSU10 were grown under acetic acid fermentation conditions, and their growth behavior was examined together with their capacity for acetic acid resistance and pellicle formation. In the fermentation process, the cells became aggregated and covered by amorphous materials in the late-log and stationary phases, but dispersed again in the second growth phase (due to overoxidation). The morphological change in the cells was accompanied by changes in sugar contents, which might be related to pellicle polysaccharide formation. To determine the relationship between pellicle formation and acetic acid resistance, a pellicle-forming R strain and a non-forming S strain were isolated, and their fermentation ability and acetic acid diffusion activity were compared. The results suggest that pellicle formation is directly related to acetic acid resistance ability, and thus is important to acetic acid fermentation in these A. pasteurianus strains.

Advances in citric acid fermentation by Aspergillus niger: biochemical aspects, membrane transport and modeling.

PubMed

Papagianni, Maria

2007-01-01

Citric acid is regarded as a metabolite of energy metabolism, of which the concentration will rise to appreciable amounts only under conditions of substantive metabolic imbalances. Citric acid fermentation conditions were established during the 1930s and 1940s, when the effects of various medium components were evaluated. The biochemical mechanism by which Aspergillus niger accumulates citric acid has continued to attract interest even though its commercial production by fermentation has been established for decades. Although extensive basic biochemical research has been carried out with A. niger, the understanding of the events relevant for citric acid accumulation is not completely understood. This review is focused on citric acid fermentation by A. niger. Emphasis is given to aspects of fermentation biochemistry, membrane transport in A. niger and modeling of the production process.

Formulation of yeast-leavened bread with reduced salt content by using a Lactobacillus plantarum fermentation product.

PubMed

Valerio, Francesca; Conte, Amalia; Di Biase, Mariaelena; Lattanzio, Veronica M T; Lonigro, S Lisa; Padalino, Lucia; Pontonio, Erica; Lavermicocca, Paola

2017-04-15

A Lactobacillus plantarum fermentation product (Bio21B), obtained after strain growth (14h) in a wheat flour-based medium, was applied in the bread-making process as taste enhancer, in order to obtain a yeast-leavened bread with reduced salt content (20% and 50%) with respect to a reference bread (REF) not containing the fermentation product. Sensory analysis indicated that the Bio21B bread with salt reduced by 50% had a pleasant taste similar to the salt-containing bread (REF). l-Glutamate and total free amino acid content did not differ between REF and Bio21B breads, while the acids lactic, acetic, phenyllactic, 4-OH-phenyllactic and indole-3-lactic were present only in Bio21B breads. Moreover, the presence of several umami (uridine monophosphate, inosine monophosphate, adenosine, and guanosine) and kokumi (γ-l-glutamyl-l-valine) taste-related molecules was ascertained both in REF and in Bio21B breads. Therefore, a possible role of the acidic molecules in compensating the negative perception of salt reduction can be hypothesized. Copyright © 2016 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stols, L.; Donnelly, M.I.; Kulkarni, G.

The malic enzyme gene of Ascaris suum was cloned into the vector pTRC99a in two forms encoding alternative amino-termini. The resulting plasmids, pMEA1 and pMEA2, were introduced into Escherichia coli NZN111, a strain that is unable to grow fermentatively because of inactivation of the genes encoding pyruvate dissimilation. Induction of pMEA1, which encodes the native animoterminus, gave better overexpression of malic enzyme, approx 12-fold compared to uninduced cells. Under the appropriate culture conditions, expression of malic enzyme allowed the fermentative dissimilation of glucose by NZN111. The major fermentation product formed in induced cultures was succinic acid.

Preparation of stable isotope-labeled peripheral cannabinoid receptor CB2 by bacterial fermentation

PubMed Central

Berger, Christian; Ho, Jenny T.C.; Kimura, Tomohiro; Hess, Sonja; Gawrisch, Klaus; Yeliseev, Alexei

2010-01-01

We developed a bacterial fermentation protocol for production of a stable isotope-labeled cannabinoid receptor CB2 for subsequent structural studies of this protein by nuclear magnetic resonance spectroscopy. The human peripheral cannabinoid receptor was expressed in Escherichia coli as a fusion with maltose binding protein and two affinity tags. The fermentation was performed in defined media comprised of mineral salts, glucose and 15N2-L-tryptophan to afford incorporation of the labeled amino acid into the protein. Medium, growth and expression conditions were optimized so that the fermentation process produced about 2 mg of purified, labeled CB2 per liter of culture medium. By performing a mass spectroscopic characterization of the purified CB2, we determined that one of the two 15N atoms in tryptophan was incorporated into the recombinant protein. NMR analysis of 15N chemical shifts strongly suggests that the 15N atoms are located in Trp-indole rings. Importantly, analysis of the peptides derived from the CNBr cleavage of the purified protein confirmed a minimum of 95% incorporation of the labeled tryptophan into the CB2 sequence. The labeled CB2, purified and reconstituted into liposomes at a protein-to-lipid molar ratio of 1:500, was functional as confirmed by activation of cognate G proteins in an in vitro coupled assay. To our knowledge, this is the first reported production of a biologically active, stable isotope-labeled G protein-coupled receptor by bacterial fermentation. PMID:20044006

Extractive Fermentation of Lactic Acid in Lactic Acid Bacteria Cultivation: A Review.

PubMed

Othman, Majdiah; Ariff, Arbakariya B; Rios-Solis, Leonardo; Halim, Murni

2017-01-01

Lactic acid bacteria are industrially important microorganisms recognized for their fermentative ability mostly in their probiotic benefits as well as lactic acid production for various applications. Nevertheless, lactic acid fermentation often suffers end-product inhibition which decreases the cell growth rate. The inhibition of lactic acid is due to the solubility of the undissociated lactic acid within the cytoplasmic membrane and insolubility of dissociated lactate, which causes acidification of cytoplasm and failure of proton motive forces. This phenomenon influences the transmembrane pH gradient and decreases the amount of energy available for cell growth. In general, the restriction imposed by lactic acid on its fermentation can be avoided by extractive fermentation techniques, which can also be exploited for product recovery.

Evaluation of fermentation kinetics of acid-treated corn cob hydrolysate for xylose fermentation in the presence of acetic acid by Pichia stipitis.

PubMed

Kashid, Mohan; Ghosalkar, Anand

2017-08-01

The efficient utilization of lignocellulosic biomass for ethanol production depends on the fermentability of the biomass hydrolysate obtained after pretreatment. In this work we evaluated the kinetics of ethanol production from xylose using Pichia stipitis in acid-treated corn cob hydrolysate. Acetic acid is one of the main inhibitors in corn cob hydrolysate that negatively impacts kinetics of xylose fermentation by P. stipitis. Unstructured kinetic model has been formulated that describes cell mass growth and ethanol production as a function of xylose, oxygen, ethanol, and acetic acid concentration. Kinetic parameters were estimated under different operating conditions affecting xylose fermentation. This is the first report on kinetics of xylose fermentation by P. stipitis which includes inhibition of acetic acid on growth and product formation. In the presence of acetic acid in the hydrolysate, the model accurately predicted reduction in maximum specific growth rate (from 0.23 to 0.15 h -1 ) and increase in ethanol yield per unit biomass (from 3 to 6.2 gg -1 ), which was also observed during experimental trials. Presence of acetic acid in the fermentation led to significant reduction in the cell growth rate, reduction in xylose consumption and ethanol production rate. The developed model accurately described physiological state of P. stipitis during corn cob hydrolysate fermentation. Proposed model can be used to predict the influence of xylose, ethanol, oxygen, and acetic acid concentration on cell growth and ethanol productivity in industrial fermentation.

L-Tryptophan Production in Escherichia coli Improved by Weakening the Pta-AckA Pathway

PubMed Central

Liu, Lina; Duan, Xuguo; Wu, Jing

2016-01-01

Acetate accumulation during the fermentation process of Escherichia coli FB-04, an L-tryptophan production strain, is detrimental to L-tryptophan production. In an initial attempt to reduce acetate formation, the phosphate acetyltransferase gene (pta) from E. coli FB-04 was deleted, forming strain FB-04(Δpta). Unfortunately, FB-04(Δpta) exhibited a growth defect. Therefore, pta was replaced with a pta variant (pta1) from E. coli CCTCC M 2016009, forming strain FB-04(pta1). Pta1 exhibits lower catalytic capacity and substrate affinity than Pta because of a single amino acid substitution (Pro69Leu). FB-04(pta1) lacked the growth defect of FB-04(Δpta) and showed improved fermentation performance. Strain FB-04(pta1) showed a 91% increase in L-tryptophan yield in flask fermentation experiments, while acetate production decreased by 35%, compared with its parent FB-04. Throughout the fed-batch fermentation process, acetate accumulation by FB-04(pta1) was slower than that by FB-04. The final L-tryptophan titer of FB-04(pta1) reached 44.0 g/L, representing a 15% increase over that of FB-04. Metabolomics analysis showed that the pta1 genomic substitution slightly decreased carbon flux through glycolysis and significantly increased carbon fluxes through the pentose phosphate and common aromatic pathways. These results indicate that this strategy enhances L-tryptophan production and decreases acetate accumulation during the L-tryptophan fermentation process. PMID:27348810

Utilization of African grains for sourdough bread making.

PubMed

Coda, Rossana; Di Cagno, Raffaella; Rizzello, Carlo G; Nionelli, Luana; Edema, Mojisola O; Gobbetti, Marco

2011-08-01

Acha and Iburu flours were singly subjected to sourdough fermentation with previously selected autochthonous starters. Sourdoughs were used (30%, wt/wt) as aroma carriers and acidifiers during short time fermentation with the addition of baker's yeast. Acha and Iburu sourdough breads were compared to wheat sourdough bread started with the same strains and to breads made with the same formula but using baker's yeast alone. During Acha and Iburu sourdough fermentations, starter lactic acid bacteria reached almost the same cell density found in wheat sourdoughs. Acidification was more intense. Iburu sourdough bread had the highest total titratable acidity, the lowest pH, and contained the highest levels of free amino acids and phytase activity. The values of in vitro protein digestibility did not differ between Acha sourdough and wheat sourdough breads, while Iburu sourdough bread showed a slightly lower value. Acha and Iburu sourdough breads showed lower specific volume and higher density with respect to wheat sourdough breads. Nevertheless, Acha and Iburu sourdough breads were preferred for hardness and resilience. As shown by sensory analysis, Acha and especially Iburu sourdough breads were appreciated for color, acid taste and flavor, and overall acceptability. This study was aimed at evaluating the technological and nutritional properties of the African cereals Acha and Iburu. Sourdough fermentation and the use of selected starters increased the nutritional and sensory qualities and the potential application for bakery industry. © 2011 Institute of Food Technologists®

Extractive Fermentation of Lactic Acid in Lactic Acid Bacteria Cultivation: A Review

PubMed Central

Othman, Majdiah; Ariff, Arbakariya B.; Rios-Solis, Leonardo; Halim, Murni

2017-01-01

Lactic acid bacteria are industrially important microorganisms recognized for their fermentative ability mostly in their probiotic benefits as well as lactic acid production for various applications. Nevertheless, lactic acid fermentation often suffers end-product inhibition which decreases the cell growth rate. The inhibition of lactic acid is due to the solubility of the undissociated lactic acid within the cytoplasmic membrane and insolubility of dissociated lactate, which causes acidification of cytoplasm and failure of proton motive forces. This phenomenon influences the transmembrane pH gradient and decreases the amount of energy available for cell growth. In general, the restriction imposed by lactic acid on its fermentation can be avoided by extractive fermentation techniques, which can also be exploited for product recovery. PMID:29209295

Lactic acid bacteria population dynamics during spontaneous fermentation of radish (Raphanus sativus L.) roots in brine.

PubMed

Pardali, Eleni; Paramithiotis, Spiros; Papadelli, Marina; Mataragas, Marios; Drosinos, Eleftherios H

2017-06-01

The aim of the present study was to assess the microecosystem development and the dynamics of the lactic acid bacteria population during spontaneous fermentation of radish (Raphanus sativus L.) roots in brine at 20 and 30 °C. In both temperatures, lactic acid bacteria prevailed the fermentation; as a result, the pH value was reduced to ca. 3.6 and total titrable acidity increased to ca. 0.4% lactic acid. Enterococci population increased and formed a secondary microbiota while pseudomonads, Enterobacteriaceae and yeasts/molds populations were below enumeration limit already before the middle of fermentation. Pediococcus pentosaceus dominated during the first days, followed by Lactobacillus plantarum that prevailed the fermentation until the end. Lactobacillus brevis was also detected during the final days of fermentation. A succession at sub-species level was revealed by the combination of RAPD-PCR and rep-PCR analyses. Glucose and fructose were the main carbohydrates detected in brine and were metabolized into lactic acid, acetic acid and ethanol.

Production of lactic acid from sucrose: strain selection, fermentation, and kinetic modeling.

PubMed

Lunelli, Betânia H; Andrade, Rafael R; Atala, Daniel I P; Wolf Maciel, Maria Regina; Maugeri Filho, Francisco; Maciel Filho, Rubens

2010-05-01

Lactic acid is an important product arising from the anaerobic fermentation of sugars. It is used in the pharmaceutical, cosmetic, chemical, and food industries as well as for biodegradable polymer and green solvent production. In this work, several bacterial strains were isolated from industrial ethanol fermentation, and the most efficient strain for lactic acid production was selected. The fermentation was conducted in a batch system under anaerobic conditions for 50 h at a temperature of 34 degrees C, a pH value of 5.0, and an initial sucrose concentration of 12 g/L using diluted sugarcane molasses. Throughout the process, pulses of molasses were added in order to avoid the cell growth inhibition due to high sugar concentration as well as increased lactic acid concentrations. At the end of the fermentation, about 90% of sucrose was consumed to produce lactic acid and cells. A kinetic model has been developed to simulate the batch lactic acid fermentation results. The data obtained from the fermentation were used for determining the kinetic parameters of the model. The developed model for lactic acid production, growth cell, and sugar consumption simulates the experimental data well.

Strategies for improving production performance of probiotic Pediococcus acidilactici viable cell by overcoming lactic acid inhibition.

PubMed

Othman, Majdiah; Ariff, Arbakariya B; Wasoh, Helmi; Kapri, Mohd Rizal; Halim, Murni

2017-11-27

Lactic acid bacteria are industrially important microorganisms recognized for fermentative ability mostly in their probiotic benefits as well as lactic acid production for various applications. Fermentation conditions such as concentration of initial glucose in the culture, concentration of lactic acid accumulated in the culture, types of pH control strategy, types of aeration mode and different agitation speed had influenced the cultivation performance of batch fermentation of Pediococcus acidilactici. The maximum viable cell concentration obtained in constant fed-batch fermentation at a feeding rate of 0.015 L/h was 6.1 times higher with 1.6 times reduction in lactic acid accumulation compared to batch fermentation. Anion exchange resin, IRA 67 was found to have the highest selectivity towards lactic acid compared to other components studied. Fed-batch fermentation of P. acidilactici coupled with lactic acid removal system using IRA 67 resin showed 55.5 and 9.1 times of improvement in maximum viable cell concentration compared to fermentation without resin for batch and fed-batch mode respectively. The improvement of the P. acidilactici growth in the constant fed-batch fermentation indicated the use of minimal and simple process control equipment is an effective approach for reducing by-product inhibition. Further improvement in the cultivation performance of P. acidilactici in fed-bath fermentation with in situ addition of anion-exchange resin significantly helped to enhance the growth of P. acidilactici by reducing the inhibitory effect of lactic acid and thus increasing probiotic production.

Lysine and Glutamic Acids as the End Products of Multi-response of Optimized Fermented Medium by Mucor mucedo KP736529.

PubMed

El-Hersh, Mohammed S; Saber, WesamEldin I A; El-Fadaly, Husain A; Mahmoud, Mohammed K

Amino acids are important for living organisms, they acting as crucial for metabolic activities and energy generation, wherein the deficiency in these amino acids cause various physiological defects. The aim of this study is to investigate the effect of some nutritional factors on the amino acids production by Mucor mucedo KP736529 during fermentation intervals. Mucor mucedo KP736529 was selected according to proteolytic activity. Corn steep liquor and olive cake were used in the fermented medium during Placket-Burman and central composite design to maximize the production of lysine and glutamic acids. During the screening by Plackett-Burman design, olive cake and Corn Steep Liquor (CSL) had potential importance for the higher production of amino acids. The individual fractionation of total amino acids showed both lysine and glutamic as the major amino acids associated with the fermentation process. Moreover, the Central Composite Design (CCD) has been adopted to explain the interaction between olive cake and CSL on the production of lysine and glutamic acids. The model recorded significant F-value, with high values of R 2, adjusted R 2 and predicted R 2 for both lysine and glutamic, indicating the validity of the data. Solving equation for maximum production of lysine recorded theoretical levels of olive cake and CSL, being 2.58 and 1.83 g L -1, respectively, with predicting value of lysine at 1.470 μg mL -1, whereas the predicting value of glutamic acid reached 0.805 mg mL -1 at levels of 2.49 and 1.93 g L -1 from olive cake and CSL, respectively. The desirability function (D) showed the actual responses being 1.473±0.009 and 0.801±0.004 μg mL -1 for lysine and glutamic acids, respectively. The model showed adequate validity to be applied in a large-scale production of both lysine and glutamic acids.

Production of citric acid using its extraction wastewater treated by anaerobic digestion and ion exchange in an integrated citric acid-methane fermentation process.

PubMed

Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

2014-08-01

In order to solve the problem of extraction wastewater pollution in citric acid industry, an integrated citric acid-methane fermentation process is proposed in this study. Extraction wastewater was treated by mesophilic anaerobic digestion and then used to make mash for the next batch of citric acid fermentation. The recycling process was done for seven batches. Citric acid production (82.4 g/L on average) decreased by 34.1 % in the recycling batches (2nd-7th) compared with the first batch. And the residual reducing sugar exceeded 40 g/L on average in the recycling batches. Pigment substances, acetic acid, ammonium, and metal ions in anaerobic digestion effluent (ADE) were considered to be the inhibitors, and their effects on the fermentation were studied. Results indicated that ammonium, Na(+) and K(+) in the ADE significantly inhibited citric acid fermentation. Therefore, the ADE was treated by acidic cation exchange resin prior to reuse to make mash for citric acid fermentation. The recycling process was performed for ten batches, and citric acid productions in the recycling batches were 126.6 g/L on average, increasing by 1.7 % compared with the first batch. This process could eliminate extraction wastewater discharge and reduce water resource consumption.

Fumaric Acid Production from Alkali-Pretreated Corncob by Fed-Batch Simultaneous Saccharification and Fermentation Combined with Separated Hydrolysis and Fermentation at High Solids Loading.

PubMed

Li, Xin; Zhou, Jin; Ouyang, Shuiping; Ouyang, Jia; Yong, Qiang

2017-02-01

Production of fumaric acid from alkali-pretreated corncob (APC) at high solids loading was investigated using a combination of separated hydrolysis and fermentation (SHF) and fed-batch simultaneous saccharification and fermentation (SSF) by Rhizopus oryzae. Four different fermentation modes were tested to maximize fumaric acid concentration at high solids loading. The highest concentration of 41.32 g/L fumaric acid was obtained from 20 % (w/v) APC at 38 °C in the combined SHF and fed-batch SSF process, compared with 19.13 g/L fumaric acid in batch SSF alone. The results indicated that a combination of SHF and fed-batch SSF significantly improved production of fumaric acid from lignocellulose by R. oryzae than that achieved with batch SSF at high solids loading.

Exploring flavour-producing core microbiota in multispecies solid-state fermentation of traditional Chinese vinegar.

PubMed

Wang, Zong-Min; Lu, Zhen-Ming; Shi, Jin-Song; Xu, Zheng-Hong

2016-05-31

Multispecies solid-state fermentation (MSSF), a natural fermentation process driven by reproducible microbiota, is an important technique to produce traditional fermented foods. Flavours, skeleton of fermented foods, was mostly produced by microbiota in food ecosystem. However, the association between microbiota and flavours and flavour-producing core microbiota are still poorly understood. Here, acetic acid fermentation (AAF) of Zhenjiang aromatic vinegar was taken as a typical case of MSSF. The structural and functional dynamics of microbiota during AAF process was determined by metagenomics and favour analyses. The dominant bacteria and fungi were identified as Acetobacter, Lactobacillus, Aspergillus, and Alternaria, respectively. Total 88 flavours including 2 sugars, 9 organic acids, 18 amino acids, and 59 volatile flavours were detected during AAF process. O2PLS-based correlation analysis between microbiota succession and flavours dynamics showed bacteria made more contribution to flavour formation than fungi. Seven genera including Acetobacter, Lactobacillus, Enhydrobacter, Lactococcus, Gluconacetobacer, Bacillus and Staphylococcus were determined as functional core microbiota for production of flavours in Zhenjiang aromatic vinegar, based on their dominance and functionality in microbial community. This study provides a perspective for bridging the gap between the phenotype and genotype of ecological system, and advances our understanding of MSSF mechanisms in Zhenjiang aromatic vinegar.

Exploring the Degradation of Gallotannins Catalyzed by Tannase Produced by Aspergillus niger GH1 for Ellagic Acid Production in Submerged and Solid-State Fermentation.

PubMed

Chávez-González, Mónica L; Guyot, Sylvain; Rodríguez-Herrera, Raul; Prado-Barragán, Arely; Aguilar, Cristóbal N

2018-06-01

Due to great interest on producing bioactive compounds for functional foods and biopharmaceuticals, it is important to explore the microbial degradation of potential sources of target biomolecules. Gallotannins are polyphenols present in nature, an example of them is tannic acid which is susceptible to enzymatic hydrolysis. This hydrolysis is performed by tannase or tannin acyl hydrolase, releasing in this way, biomolecules with high-added value. In the present study, chemical profiles obtained after fungal degradation of tannic acid under two bioprocesses (submerged fermentation (SmF) and solid state fermentation (SSF)) were determined. In both fermentation systems (SmF and SSF), Aspergillus niger GH1 strain and tannic acid as a sole carbon source and inducer were used (the presence of tannic acid promotes production of enzyme tannase). In case of SSF, polyurethane foam (PUF) was used like as support of fermentation; culture medium only was used in case of submerged fermentation. Fermentation processes were monitored during 72 h; samples were taken kinetically every 8 h; and all extracts obtained were partially purified to obtain polyphenolic fraction and then were analyzed by liquid chromatography-mass spectrometry (LC-MS). Molecules like gallic acid and n-galloyl glucose were identified as intermediates in degradation of tannic acid; during SSF was identified ellagic acid production. The results obtained in this study will contribute to biotechnological production of ellagic acid.

Overexpression and optimization of glutamate decarboxylase in Lactobacillus plantarum Taj-Apis362 for high gamma-aminobutyric acid production

PubMed Central

Tajabadi, Naser; Baradaran, Ali; Ebrahimpour, Afshin; Rahim, Raha A; Bakar, Fatimah A; Manap, Mohd Yazid A; Mohammed, Abdulkarim S; Saari, Nazamid

2015-01-01

Gamma-aminobutyric acid (GABA) is an important bioactive compound biosynthesized by microorganisms through decarboxylation of glutamate by glutamate decarboxylase (GAD). In this study, a full-length GAD gene was obtained by cloning the template deoxyribonucleic acid to pTZ57R/T vector. The open reading frame of the GAD gene showed the cloned gene was composed of 1410 nucleotides and encoded a 469 amino acids protein. To improve the GABA-production, the GAD gene was cloned into pMG36e-LbGAD, and then expressed in Lactobacillus plantarum Taj-Apis362 cells. The overexpression was confirmed by SDS-PAGE and GAD activity, showing a 53 KDa protein with the enzyme activity increased by sevenfold compared with the original GAD activity. The optimal fermentation conditions for GABA production established using response surface methodology were at glutamic acid concentration of 497.973 mM, temperature 36°C, pH 5.31 and time 60 h. Under the conditions, maximum GABA concentration obtained (11.09 mM) was comparable with the predicted value by the model at 11.23 mM. To our knowledge, this is the first report of successful cloning (clone-back) and overexpression of the LbGAD gene from L. plantarum to L. plantarum cells. The recombinant Lactobacillus could be used as a starter culture for direct incorporation into a food system during fermentation for production of GABA-rich products. PMID:25757029

Effects of selected lactic acid bacteria on the characteristics of amaranth sourdough.

PubMed

Jekle, Mario; Houben, Andreas; Mitzscherling, Martin; Becker, Thomas

2010-10-01

As the processing of amaranth in baked goods is challenging, the use of sourdough fermentation is a promising possibility to exploit the advantages of this raw material. In this study the fermentation properties of Lactobacillus plantarum, Lactobacillus paralimentarius and Lactobacillus helveticus in amaranth-based sourdough were examined in order to validate them as starter cultures. pH, total titratable acidity (TTA) and lactic/acetic acid ratio of the sourdough and sensory properties of the resulting wheat bread were evaluated using fermentation temperatures of 30 and 35 °C. While fermentation pH, TTA and lactic acid concentration showed small variations with the use of L. plantarum and L. paralimentarius, L. helveticus reached the most intensive acidification after initial adaptation to the substrate. Acetic acid production was independent of lactic acid metabolism. Furthermore, the lactic/acetic acid ratio exceeded recommendation by 10-35 times (fermentation quotient 25-82). Sensory evaluation showed no significant differences between the two fermentation temperatures but differences among the three micro-organisms. The results provide relevant information on the fermentation properties required of a customised starter for amaranth flour. Copyright © 2010 Society of Chemical Industry.

Production of polymalic acid and malic acid by Aureobasidium pullulans fermentation and acid hydrolysis.

PubMed

Zou, Xiang; Zhou, Yipin; Yang, Shang-Tian

2013-08-01

Malic acid is a dicarboxylic acid widely used in the food industry and also a potential C4 platform chemical that can be produced from biomass. However, microbial fermentation for direct malic acid production is limited by low product yield, titer, and productivity due to end-product inhibition. In this work, a novel process for malic acid production from polymalic acid (PMA) fermentation followed by acid hydrolysis was developed. First, a PMA-producing Aureobasidium pullulans strain ZX-10 was screened and isolated. This microbe produced PMA as the major fermentation product at a high-titer equivalent to 87.6 g/L of malic acid and high-productivity of 0.61 g/L h in free-cell fermentation in a stirred-tank bioreactor. Fed-batch fermentations with cells immobilized in a fibrous-bed bioreactor (FBB) achieved the highest product titer of 144.2 g/L and productivity of 0.74 g/L h. The fermentation produced PMA was purified by adsorption with IRA-900 anion-exchange resins, achieving a ∼100% purity and a high recovery rate of 84%. Pure malic acid was then produced from PMA by hydrolysis with 2 M sulfuric acid at 85°C, which followed the first-order reaction kinetics. This process provides an efficient and economical way for PMA and malic acid production, and is promising for industrial application. Copyright © 2013 Wiley Periodicals, Inc.

Production, isolation, and purification of L-asparaginase from Pseudomonas aeruginosa 50071 using solid-state fermentation.

PubMed

El-Bessoumy, Ashraf A; Sarhan, Mohamed; Mansour, Jehan

2004-07-31

The L-asparaginase (E. C. 3. 5. 1. 1) enzyme was purified to homogeneity from Pseudomonas aeruginosa 50071 cells that were grown on solid-state fermentation. Different purification steps (including ammonium sulfate fractionation followed by separation on Sephadex G-100 gel filtration and CM-Sephadex C50) were applied to the crude culture filtrate to obtain a pure enzyme preparation. The enzyme was purified 106-fold and showed a final specific activity of 1900 IU/mg with a 43% yield. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the purified enzyme revealed it was one peptide chain with M(r) of 160 kDa. A Lineweaver-Burk analysis showed a K(m) value of 0.147 mM and V(max) of 35.7 IU. The enzyme showed maximum activity at pH 9 when incubated at 37 degrees C for 30 min. The amino acid composition of the purified enzyme was also determined.

Models of glycolysis: Glyceraldehyde as a source of energy and monomers for prebiotic condensation reactions

NASA Technical Reports Server (NTRS)

Weber, A. L.

1986-01-01

All organisms require energy in a chemical form for maintenance and growth. In contemporary life this chemical energy is obtained by the synthesis of the phosphoanhydride bonds of ATP. Among the biological processes that yield ATP, fermentation is generally considered primitive, because it operates under anaerobic conditions by substrate-level phosphorylation which does not require compartmentation by membranes. Fermentation by the glycolytic pathway, which is found in almost every living cell, is an especially attractive energy source for primitive life. Glycolysis not only produces useful chemical energy (ATP), but intermediates of this pathway are also involved in amino acid synthesis and photosynthetic carbon-fixation. It is believed that energy and substrates needed for the origin of life were provided by nonenzymatic chemical reactions that resemble the enzyme-mediated reactions of glycolysis. These nonenzymatic reactions would have provided a starting point for the evolutionary development of glycolysis.

FERMENTATION OF ETHYLENE GLYCOL BY CLOSTRIDIUM GLYCOLICUM, SP. N1

PubMed Central

Gaston, Lamont W.; Stadtman, E. R.

1963-01-01

Gaston, Lamont W. (National Heart Institute, National Institutes of Health, Bethesda, Md.) and E. R. Stadtman. Fermentation of ethylene glycol by Clostridium glycolicum, sp. n. J. Bacteriol. 85:356–362. 1963.—An anaerobic organism which utilizes ethylene glycol as a source of energy and carbon has been isolated from mud. It is a long (5 μ), slender, motile, gram-positive, spore-forming rod, with peritrichous flagellae. It grows well from 22 to 37 C at pH 7.4 to 7.6, and ferments glucose, fructose, sorbitol, dulcitol, and cellulose. It does not reduce nitrates, form indole, or cause hemolysis or proteolysis except for a slight attack on coagulated egg albumin. Fifteen amino acids and the vitamins biotin and pantothenate are required for optimal growth on ethylene glycol. Analogues other than propylene glycol do not support growth. Ethylene glycol and propylene glycol are stoichiometrically converted to equal amounts of the respective acid and alcohol. PMID:13946772

Prediction of reaction knockouts to maximize succinate production by Actinobacillus succinogenes.

PubMed

Nag, Ambarish; St John, Peter C; Crowley, Michael F; Bomble, Yannick J

2018-01-01

Succinate is a precursor of multiple commodity chemicals and bio-based succinate production is an active area of industrial bioengineering research. One of the most important microbial strains for bio-based production of succinate is the capnophilic gram-negative bacterium Actinobacillus succinogenes, which naturally produces succinate by a mixed-acid fermentative pathway. To engineer A. succinogenes to improve succinate yields during mixed acid fermentation, it is important to have a detailed understanding of the metabolic flux distribution in A. succinogenes when grown in suitable media. To this end, we have developed a detailed stoichiometric model of the A. succinogenes central metabolism that includes the biosynthetic pathways for the main components of biomass-namely glycogen, amino acids, DNA, RNA, lipids and UDP-N-Acetyl-α-D-glucosamine. We have validated our model by comparing model predictions generated via flux balance analysis with experimental results on mixed acid fermentation. Moreover, we have used the model to predict single and double reaction knockouts to maximize succinate production while maintaining growth viability. According to our model, succinate production can be maximized by knocking out either of the reactions catalyzed by the PTA (phosphate acetyltransferase) and ACK (acetyl kinase) enzymes, whereas the double knockouts of PEPCK (phosphoenolpyruvate carboxykinase) and PTA or PEPCK and ACK enzymes are the most effective in increasing succinate production.

Effects of koji-making with mixed strains on physicochemical and sensory properties of Chinese-type soy sauce.

PubMed

Chen, Zhi-Yao; Feng, Yun-Zi; Cui, Chun; Zhao, Hai-Feng; Zhao, Mou-Ming

2015-08-15

Two kinds of soy sauces were prepared with Aspergillus oryzae koji (SSAO) and mixed koji (SSAOM, A. oryzae mouldstarter:Monascus purpureus mouldstarter = 1:2, w/w) respectively. The effects of mixed koji on the essential indices, oxygen radical absorption capacity, color indices, free amino acids and volatile compounds of soy sauce have been studied, followed by a sensory evaluation between SSAO and SSAOM. The contents of non-salt soluble solid, reducing sugar, total acid, total nitrogen and amino nitrogen in SSAOM increased by 21.50%, 9.88%, 15.35%, 5.98% and 41.43%, respectively, compared with the control SSAO, owing to the higher activities of acid protease and glucoamylase in the mixed koji. Moreover, SSAOM showed higher antioxidant activity, higher levels of free amino acids and much more attractive color. Meanwhile, flavor groups such as esters, aldehydes, pyrazines and sulfur-containing compounds in SSAOM were also improved. The contents of free amino acids and aroma compounds were consistent with the sensory evaluation. According to descriptive sensory analysis, SSAOM showed higher intensity for sweet and umami attributes; in addition, higher flowery, burnt, fruity and caramel-like attributes were perceived in SSAOM, while SSAO showed higher ethanolic and sour attributes. The investigated soy sauce prepared with mixed koji can be considered as an effective method to accelerate the fermentation process and improve the flavor of soy sauce. © 2014 Society of Chemical Industry.

Omics-based approaches reveal phospholipids remodeling of Rhizopus oryzae responding to furfural stress for fumaric acid-production from xylose.

PubMed

Pan, Xinrong; Liu, Huanhuan; Liu, Jiao; Wang, Cheng; Wen, Jianping

2016-12-01

In order to relieve the toxicity of furfural on Rhizopus oryzae fermentation, the molecular mechanism of R. oryzae responding to furfural stress for fumaric acid-production was investigated by omics-based approaches. In metabolomics analysis, 29 metabolites including amino acid, sugars, polyols and fatty acids showed significant changes for maintaining the basic cell metabolism at the cost of lowering fumaric acid production. To further uncover the survival mechanism, lipidomics was carried out, revealing that phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol and polyunsaturated acyl chains might be closely correlated with R. oryzae's adapting to furfural stress. Based on the above omics analysis, lecithin, inositol and soybean oil were exogenously supplemented separately with an optimized concentration in the presence of furfural, which increased fumaric acid titer from 5.78g/L to 10.03g/L, 10.05g/L and 12.13g/L (increased by 73.5%, 73.8% and 110%, respectively). These findings provide a methodological guidance for hemicellulose-fumaric acid development. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exploring flavour-producing core microbiota in multispecies solid-state fermentation of traditional Chinese vinegar

PubMed Central

Wang, Zong-Min; Lu, Zhen-Ming; Shi, Jin-Song; Xu, Zheng-Hong

2016-01-01

Multispecies solid-state fermentation (MSSF), a natural fermentation process driven by reproducible microbiota, is an important technique to produce traditional fermented foods. Flavours, skeleton of fermented foods, was mostly produced by microbiota in food ecosystem. However, the association between microbiota and flavours and flavour-producing core microbiota are still poorly understood. Here, acetic acid fermentation (AAF) of Zhenjiang aromatic vinegar was taken as a typical case of MSSF. The structural and functional dynamics of microbiota during AAF process was determined by metagenomics and favour analyses. The dominant bacteria and fungi were identified as Acetobacter, Lactobacillus, Aspergillus, and Alternaria, respectively. Total 88 flavours including 2 sugars, 9 organic acids, 18 amino acids, and 59 volatile flavours were detected during AAF process. O2PLS-based correlation analysis between microbiota succession and flavours dynamics showed bacteria made more contribution to flavour formation than fungi. Seven genera including Acetobacter, Lactobacillus, Enhydrobacter, Lactococcus, Gluconacetobacer, Bacillus and Staphylococcus were determined as functional core microbiota for production of flavours in Zhenjiang aromatic vinegar, based on their dominance and functionality in microbial community. This study provides a perspective for bridging the gap between the phenotype and genotype of ecological system, and advances our understanding of MSSF mechanisms in Zhenjiang aromatic vinegar. PMID:27241188

Characterization of soybean protein hydrolysates able to promote the proliferation of Streptococcus thermophilus ST.

PubMed

Hongfei, Zhao; Fengling, Bai; Fang, Zhou; Walczak, Piotr; Xiangning, Jiang; Bolin, Zhang

2013-04-01

How soybean protein hydrolysates (SPHs) to favor the growth of S. thermophilus ST were investigated. Hydrolyzed soybean protein was fractionated to 4 fragments, that is, SPH-I, SPH-II, SPH-III, and SPH-IV according to their molecular weight sizes. SPHs can improve the growth of strain ST, in which SPH-IV, with the molecular weight of less than 5 kD, significantly promoted the growth of strain ST. The cell counts of strain ST grew quickly from 7.71 to 9.78 (log CFU/mL) when the concentrations of SPH-IV ranging from 0% to 1%. Moreover, 2 chemically defined media (CDMs) were used to test their roles in maintaining the viability of strain ST. CDMs only maintained the survival of strain ST, but SPH-IV had the promotional effects on proliferation of the bacteria. SPH-IV was further characterized to be oligopeptides that contain 2 to 8 amino acids and free amino acids by high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis. The amino acid compositions showed that SPH-IV contained more essential amino acids, which were necessary for the growth of S. thermophilus ST. Clearly, SPH-IV could be used as an exogenous nitrogen supplement to enhance the proliferation of S. thermophilus ST and other lactic acid bacteria, and the data from small scale-up fermentation also supported this point. © 2013 Institute of Food Technologists®

Efficient non-sterilized fermentation of biomass-derived xylose to lactic acid by a thermotolerant Bacillus coagulans NL01.

PubMed

Ouyang, Jia; Cai, Cong; Chen, Hai; Jiang, Ting; Zheng, Zhaojuan

2012-12-01

Xylose is the major pentose and the second most abundant sugar in lignocellulosic feedstock. Its efficient utilization is regarded as a technical barrier to the commercial production of bulk chemicals from lignocellulosic biomass. This work aimed at evaluating the lactic acid production from the biomass-derived xylose using non-sterilized fermentation by Bacillus coagulans NL01. A maximum lactic acid concentration of about 75 g/L was achieved from xylose of 100 g/L after 72 h batch fermentation. Acetic acid and levulinic acid were identified as important inhibitors in xylose fermentation, which markedly reduced lactic acid productivity at 15 and 1.0 g/L, respectively. But low concentrations of formic acid (<2 g/L) exerted a stimulating effect on the lactic acid production. When prehydrolysate containing total 25.45 g/L monosaccharide was fermented with B. coagulans NL01, the same preference for glucose, xylose, and arabinose was observed and18.2 g/L lactic acid was obtained after 48 h fermentation. These results proved that B. coagulans NL01 was potentially well-suited for producing lactic acid from underutilized xylose-rich prehydrolysates.

Prediction of reaction knockouts to maximize succinate production by Actinobacillus succinogenes

PubMed Central

Nag, Ambarish; St. John, Peter C.; Crowley, Michael F.

2018-01-01

Succinate is a precursor of multiple commodity chemicals and bio-based succinate production is an active area of industrial bioengineering research. One of the most important microbial strains for bio-based production of succinate is the capnophilic gram-negative bacterium Actinobacillus succinogenes, which naturally produces succinate by a mixed-acid fermentative pathway. To engineer A. succinogenes to improve succinate yields during mixed acid fermentation, it is important to have a detailed understanding of the metabolic flux distribution in A. succinogenes when grown in suitable media. To this end, we have developed a detailed stoichiometric model of the A. succinogenes central metabolism that includes the biosynthetic pathways for the main components of biomass—namely glycogen, amino acids, DNA, RNA, lipids and UDP-N-Acetyl-α-D-glucosamine. We have validated our model by comparing model predictions generated via flux balance analysis with experimental results on mixed acid fermentation. Moreover, we have used the model to predict single and double reaction knockouts to maximize succinate production while maintaining growth viability. According to our model, succinate production can be maximized by knocking out either of the reactions catalyzed by the PTA (phosphate acetyltransferase) and ACK (acetyl kinase) enzymes, whereas the double knockouts of PEPCK (phosphoenolpyruvate carboxykinase) and PTA or PEPCK and ACK enzymes are the most effective in increasing succinate production. PMID:29381705

Metabolic engineering of Corynebacterium glutamicum ATCC13869 for L-valine production.

PubMed

Chen, Cheng; Li, Yanyan; Hu, Jinyu; Dong, Xunyan; Wang, Xiaoyuan

2015-05-01

In this study, an L-valine-producing strain was developed from Corynebacterium glutamicum ATCC13869 through deletion of the three genes aceE, alaT and ilvA combined with the overexpression of six genes ilvB, ilvN, ilvC, lrp1, brnF and brnE. Overexpression of lrp1 alone increased L-valine production by 16-fold. Deletion of the aceE, alaT and ilvA increased L-valine production by 44-fold. Overexpression of the six genes ilvB, ilvN, ilvC, lrp1, brnE and brnF in the triple deletion mutant WCC003 further increased L-valine production. The strain WCC003/pJYW-4-ilvBNC1-lrp1-brnFE produced 243mM L-valine in flask cultivation and 437mM (51g/L) L-valine in fed-batch fermentation and lacked detectable amino-acid byproduct such as l-alanine and l-isoleucine that are usually found in the fermentation of L-valine-producing C. glutamicum. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

27 CFR 24.182 - Use of acid to correct natural deficiencies.

Code of Federal Regulations, 2010 CFR

2010-04-01

... during fermentation, to grapes or juice from grapes. In addition, after fermentation is completed, citric..., during or after fermentation, may not increase the fixed acid level of the finished wine (calculated as...

Exploration of amino acid biomarkers in polar ice with the Mars Organic Analyzer

NASA Astrophysics Data System (ADS)

Jayarajah, C.; Botta, O.; Aubrey, A.; Parker, E.; Bada, J.; Mathies, R.

2009-05-01

A portable microfabricated capillary electrophoresis (CE) system named the Mars Organic Analyzer (MOA) has been developed to analyze fluorescently-labeled biomarkers including amino acids, amines, nucleobases, and amino sugars with the goal of life detection on Mars (1,2). This technology has also been shown to be effective in screening the formation of biogenic amines during fermentation (3). The MOA is a part of the Urey instrument package that has been selected for the 2016 European ExoMars mission by ESA. The identification of recent gully erosion sites, observations of ice on and beneath the surface of Mars, and the discovery of large reservoirs of sub-surface ice on Mars point to water-ice as an important target for astrobiological analyses. In addition, the ice samples on the Moon, Mercury, Europa and Enceladus are of interest due to the possibility that they may contain information on biogenic material relevant to the evolution of life. We explore here the use of the MOA instrument for the analysis of amino acids in polar ice samples. The amino acids valine, alanine/serine, glycine, glutamic acid, and aspartic acid were found in the parts-per-billion range from Greenland ice-core samples. Chiral analysis of these samples yielded D/L ratios of 0.51/0.09 for alanine/serine and 0.14/0.06 for aspartic acid. Individual amino acids in the parts-per-trillion range were found in Antarctic ice samples collected from the surface of a meteorite collection area. The distinct amino acid and amine content of these samples indicates that further biomarker characterization of ice samples as a function of sampling location, depth, and structural features will be highly informative. The rapid sensitive analysis capabilities demonstrated here establish the feasibility of using the MOA to analyze the biomarker content of ice samples in planetary exploration. 1. Skelley, A. M.; Scherer, J. R.; Aubrey, A. D.; Grover, W. H.; Ivester, R. H. C., Ehrenfreund, P.; Grunthaner, F. J.; Bada, J. L.; Mathies, R. A. PNAS, 2005, 192, 1041. 2. Skelley, A. M., Cleaves, H. J., Jayarajah, C. N., Bada, J. L. and Mathies, R. A., Astrobiology 2006, 6, 824. 3. Jayarajah, C.N., Skelley, A.M., Fortner, A.D., and Mathies, R.A., Anal. Chem. 2007, 79, 21, 8162.

Polymalic acid fermentation by Aureobasidium pullulans for malic acid production from soybean hull and soy molasses: Fermentation kinetics and economic analysis.

PubMed

Cheng, Chi; Zhou, Yipin; Lin, Meng; Wei, Peilian; Yang, Shang-Tian

2017-01-01

Polymalic acid (PMA) production by Aureobasidium pullulans ZX-10 from soybean hull hydrolysate supplemented with corn steep liquor (CSL) gave a malic acid yield of ∼0.4g/g at a productivity of ∼0.5g/L·h. ZX-10 can also ferment soy molasses, converting all carbohydrates including the raffinose family oligosaccharides to PMA, giving a high titer (71.9g/L) and yield (0.69g/g) at a productivity of 0.29g/L·h in fed-batch fermentation under nitrogen limitation. A higher productivity of 0.64g/L·h was obtained in repeated batch fermentation with cell recycle and CSL supplementation. Cost analysis for a 5000 MT plant shows that malic acid can be produced at $1.10/kg from soy molasses, $1.37/kg from corn, and $1.74/kg from soybean hull. At the market price of $1.75/kg, malic acid production from soy molasses via PMA fermentation offers an economically competitive process for industrial production of bio-based malic acid. Copyright © 2016 Elsevier Ltd. All rights reserved.

Engineering Escherichia coli to overproduce aromatic amino acids and derived compounds.

PubMed

Rodriguez, Alberto; Martínez, Juan A; Flores, Noemí; Escalante, Adelfo; Gosset, Guillermo; Bolivar, Francisco

2014-09-09

The production of aromatic amino acids using fermentation processes with recombinant microorganisms can be an advantageous approach to reach their global demands. In addition, a large array of compounds with alimentary and pharmaceutical applications can potentially be synthesized from intermediates of this metabolic pathway. However, contrary to other amino acids and primary metabolites, the artificial channelling of building blocks from central metabolism towards the aromatic amino acid pathway is complicated to achieve in an efficient manner. The length and complex regulation of this pathway have progressively called for the employment of more integral approaches, promoting the merge of complementary tools and techniques in order to surpass metabolic and regulatory bottlenecks. As a result, relevant insights on the subject have been obtained during the last years, especially with genetically modified strains of Escherichia coli. By combining metabolic engineering strategies with developments in synthetic biology, systems biology and bioprocess engineering, notable advances were achieved regarding the generation, characterization and optimization of E. coli strains for the overproduction of aromatic amino acids, some of their precursors and related compounds. In this paper we review and compare recent successful reports dealing with the modification of metabolic traits to attain these objectives.

Techno-economics of carbon preserving butanol production using a combined fermentative and catalytic approach.

PubMed

Nilsson, Robert; Bauer, Fredric; Mesfun, Sennai; Hulteberg, Christian; Lundgren, Joakim; Wännström, Sune; Rova, Ulrika; Berglund, Kris Arvid

2014-06-01

This paper presents a novel process for n-butanol production which combines a fermentation consuming carbon dioxide (succinic acid fermentation) with subsequent catalytic reduction steps to add hydrogen to form butanol. Process simulations in Aspen Plus have been the basis for the techno-economic analyses performed. The overall economy for the novel process cannot be justified, as production of succinic acid by fermentation is too costly. Though, succinic acid price is expected to drop drastically in a near future. By fully integrating the succinic acid fermentation with the catalytic conversion the need for costly recovery operations could be reduced. The hybrid process would need 22% less raw material than the butanol fermentation at a succinic acid fermentation yield of 0.7g/g substrate. Additionally, a carbon dioxide fixation of up to 13ktonnes could be achieved at a plant with an annual butanol production of 10ktonnes. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Effect of fermentation inhibitors in the presence and absence of activated charcoal on the growth of Saccharomyces cerevisiae.

PubMed

Kim, Sung-Koo; Park, Don-Hee; Song, Se Hee; Wee, Young-Jung; Jeong, Gwi-Taek

2013-06-01

The acidic hydrolysis of biomass generates numerous inhibitors of fermentation, which adversely affect cell growth and metabolism. The goal of the present study was to determine the effects of fermentation inhibitors on growth and glucose consumption by Saccharomyces cerevisiae. We also conducted in situ adsorption during cell cultivation in synthetic broth containing fermentation inhibitors. In order to evaluate the effect of in situ adsorption on cell growth, five inhibitors, namely 5-hydroxymethylfurfural, levulinic acid, furfural, formic acid, and acetic acid, were introduced into synthetic broth. The existence of fermentation inhibitors during cell culture adversely affects cell growth and sugar consumption. Furfural, formic acid, and acetic acid were the most potent inhibitors in our culture system. The in situ adsorption of inhibitors by the addition of activated charcoal to the synthetic broth increased cell growth and sugar consumption. Our results indicate that detoxification of fermentation media by in situ adsorption may be useful for enhancing biofuel production.

Aptitude of Saccharomyces yeasts to ferment unripe grapes harvested during cluster thinning for reducing alcohol content of wine.

PubMed

Bovo, Barbara; Nadai, Chiara; Vendramini, Chiara; Fernandes Lemos Junior, Wilson Josè; Carlot, Milena; Skelin, Andrea; Giacomini, Alessio; Corich, Viviana

2016-11-07

Among the viticultural techniques developed to obtain wine with reduced alcohol content, the use of unripe grapes with low sugar and high malic acid concentration, harvested at cluster thinning, was recently explored. So far, no studies have evaluated the fermentation performances of Saccharomyces in unripe grape musts, in terms of fermentation ability and reducing malic acid contents, to improve the quality of this low-alcohol beverage. In this work, we evaluated 24 S. cerevisiae strains isolated from Italian and Croatian vineyards with different fermentation aptitudes. Moreover, four S. paradoxus were considered, as previous works demonstrated that strains belonging to this species were able to degrade high malic acid amounts in standard musts. The industrial strain S. cerevisiae 71B was added as reference. Sugar and malic acid contents were modified in synthetic musts in order to understand the effect of their concentrations on alcoholic fermentation and malic acid degradation. S. cerevisiae fermentation performances improved when glucose concentration decreased and malic acid level increased. The conditions that simulate unripe grape must, i.e. low glucose and high malic acid content were found to enhance S. cerevisiae ability to degrade malic acid. On the contrary, S. paradoxus strains were able to degrade high amounts of malic acid only in conditions that resemble ripe grape must, i.e. high glucose and low malic acid concentration. In fermentation trials when low glucose concentrations were used, at high malic acid levels S. cerevisiae strains produced higher glycerol than at low malic acid condition. Malic acid degradation ability, tested on the best performing S. cerevisiae strains, was enhanced in fermentation trials when unripe grape must was used. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization of protease and effects of temperature and salinity on the biochemical changes during fermentation of Antarctic krill.

PubMed

Fan, Yan; Tian, Lili; Xue, Yong; Li, Zhaojie; Hou, Hu; Xue, Changhu

2017-08-01

Despite their abundance, Antarctic krill are underutilized because of numerous difficulties in their commercial processing. Ideally, fermentation technology can be applied to transform them into a popular condiment. In addition to the exploration of protease properties, the present study aimed to evaluate proteinase activity, pH, amino nitrogen, and histamine formation during fermentation at different temperatures and salt treatments. Even though the activity of Antarctic krill protease reached a maximum at 40 °C and pH 7, it was stable at 30 °C and pH 7-9. Among the metal ions tested, Ca 2+ , Mg 2+ and K + increased protease activity, in contrast to Zn 2+ and Cu 2+ . Within each treatment, the highest protease activity and amino nitrogen content, as well as the lowest histamine level, were observed on day 12 of fermentation. Treatment at 35 °C with 180 g kg -1 salt led to the production of maximum amino nitrogen (0.0352 g kg -1 ) and low histamine (≤0.0497 g kg -1 ). Krill paste fermented for 12 days at 35 °C with 180 g kg -1 salt exhibited the optimal quality and properties, suggesting an efficient method for fermentation of Antarctic krill and other aquatic resources. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Identification of fermentation inhibitors in wood hydrolyzates and removal of inhibitors by ion exchange and liquid-liquid extraction

NASA Astrophysics Data System (ADS)

Luo, Caidian

1998-12-01

Common methods employed in the ethanol production from biomass consist of chemical or enzymatic degradation of biomass into sugars and then fermentation of sugars into ethanol or other chemicals. However, some degradation products severely inhibit the fermentation processes and substantially reduce the efficiency of ethanol production. How to remove inhibitors from the reaction product mixture and increase the production efficiency are critical in the commercialization of any processes of energy from biomass. The present study has investigated anion exchange and liquid-liquid extraction as potential methods for inhibitor removal. An analytical method has been developed to identify the fermentation inhibitors in a hydrolyzate. The majority of inhibitors present in hybrid poplar hydrolyzate have positively been identified. Ion exchange with weak basic Dowex-MWA-1 resin has been proved to be an effective mean to remove fermentation inhibitors from hybrid poplar hydrolyzate and significantly increase the fermentation productivity. Extraction with n-butanol might be a preferred way to remove inhibitors from wood hydrolyzates and improve the fermentability of sugars in the hydrolyzates. n-Butanol also removes some glucose, mannose and xylose from the hydrolyzate. Inhibitor identification reveals that lignin and sugar degradation compounds including both aromatic and aliphatic aldehydes and carboxylic acids formed in hydrolysis, plus fatty acids and other components from wood extractives are major fermentation inhibitors in Sacchromyces cerevisiae fermentation. There are 35 components identified as fermentation inhibitors. Among them, 4-hydroxy benzoic acid, 3,4-dihydroxy benzoic acid, syringic acid, syringaldehyde, and ferulic acid are among the most abundant aromatic inhibitors in hybrid poplar hydrolyzate. The conversion of aldehyde groups into carboxylic acid groups in the nitric acid catalyzed hydrolysis reduces the toxicity of the hydrolyzate. A wide spectrum of aliphatic acids has been identified in the wood hydrolyzate studied. They are potential fermentation inhibitors probably similar to acetic acid. Ethyl acetate extraction has also been demonstrated to be a possible method to remove fermentation inhibitors from hydrolyzates. (Abstract shortened by UMI.)

Biofuel and chemical production by recombinant microorganisms via fermentation of proteinaceous biomass

DOEpatents

Liao, James C.; Cho, Kwang Myung; Yan, Yajun; Huo, Yixin

2016-03-15

Provided herein are metabolically modified microorganisms characterized by having an increased keto-acid flux when compared with the wild-type organism and comprising at least one polynucleotide encoding an enzyme that when expressed results in the production of a greater quantity of a chemical product when compared with the wild-type organism. The recombinant microorganisms are useful for producing a large number of chemical compositions from various nitrogen containing biomass compositions and other carbon sources. More specifically, provided herein are methods of producing alcohols, acetaldehyde, acetate, isobutyraldehyde, isobutyric acid, n-butyraldehyde, n-butyric acid, 2-methyl-1-butyraldehyde, 2-methyl-1-butyric acid, 3-methyl-1-butyraldehyde, 3-methyl-1-butyric acid, ammonia, ammonium, amino acids, 2,3-butanediol, 1,4-butanediol, 2-methyl-1,4-butanediol, 2-methyl-1,4-butanediamine, isobutene, itaconate, acetoin, acetone, isobutene, 1,5-diaminopentane, L-lactic acid, D-lactic acid, shikimic acid, mevalonate, polyhydroxybutyrate (PHB), isoprenoids, fatty acids, homoalanine, 4-aminobutyric acid (GABA), succinic acid, malic acid, citric acid, adipic acid, p-hydroxy-cinnamic acid, tetrahydrofuran, 3-methyl-tetrahydrofuran, gamma-butyrolactone, pyrrolidinone, n-methylpyrrolidone, aspartic acid, lysine, cadeverine, 2-ketoadipic acid, and/or S-adenosyl-methionine (SAM) from a suitable nitrogen rich biomass.

Lactic acid production from Sophora flavescens residues pretreated with sodium hydroxide: Reutilization of the pretreated liquor during fermentation.

PubMed

Wang, Juan; Gao, Ming; Liu, Jianguo; Wang, Qunhui; Wang, Cong; Yin, Zihe; Wu, Chuanfu

2017-10-01

The feasibility of lactic acid production from Sophora flavescens residues (SFRs) pretreated with sodium hydroxide with the reutilization of the pretreated liquor during fermentation was investigated. After sodium hydroxide pretreatment, 67.5% of the lignin was removed, and hydrolysis efficiency increased from 37.3% to 79.2%. The reutilization of pretreated liquor at 50% loading during open fermentation of unwashed SFR increased lactic acid production by 34.1%. The pretreated liquor acted as pH buffer and resulted in stable pH and high cellulase activity during fermentation. Inhibitors in the pretreated liquor did not affect the growth of lactic acid bacteria but severely inhibited the growth of ethanol-producing yeast. Consequently, lactic acid production increased and ethanol production was zero at 50% loading. Water consumption during pretreatment and fermentation with 50% pretreated liquor was 1.341L per 100g SFR, which was 67.6% lower than that during fermentation with washed SFR. Copyright © 2017 Elsevier Ltd. All rights reserved.

Efficient production of optically pure D-lactic acid from raw corn starch by using a genetically modified L-lactate dehydrogenase gene-deficient and alpha-amylase-secreting Lactobacillus plantarum strain.

PubMed

Okano, Kenji; Zhang, Qiao; Shinkawa, Satoru; Yoshida, Shogo; Tanaka, Tsutomu; Fukuda, Hideki; Kondo, Akihiko

2009-01-01

In order to achieve direct and efficient fermentation of optically pure D-lactic acid from raw corn starch, we constructed L-lactate dehydrogenase gene (ldhL1)-deficient Lactobacillus plantarum and introduced a plasmid encoding Streptococcus bovis 148 alpha-amylase (AmyA). The resulting strain produced only D-lactic acid from glucose and successfully expressed amyA. With the aid of secreting AmyA, direct D-lactic acid fermentation from raw corn starch was accomplished. After 48 h of fermentation, 73.2 g/liter of lactic acid was produced with a high yield (0.85 g per g of consumed sugar) and an optical purity of 99.6%. Moreover, a strain replacing the ldhL1 gene with an amyA-secreting expression cassette was constructed. Using this strain, direct D-lactic acid fermentation from raw corn starch was accomplished in the absence of selective pressure by antibiotics. This is the first report of direct D-lactic acid fermentation from raw starch.

Efficient Production of Optically Pure d-Lactic Acid from Raw Corn Starch by Using a Genetically Modified l-Lactate Dehydrogenase Gene-Deficient and α-Amylase-Secreting Lactobacillus plantarum Strain▿

PubMed Central

Okano, Kenji; Zhang, Qiao; Shinkawa, Satoru; Yoshida, Shogo; Tanaka, Tsutomu; Fukuda, Hideki; Kondo, Akihiko

2009-01-01

In order to achieve direct and efficient fermentation of optically pure d-lactic acid from raw corn starch, we constructed l-lactate dehydrogenase gene (ldhL1)-deficient Lactobacillus plantarum and introduced a plasmid encoding Streptococcus bovis 148 α-amylase (AmyA). The resulting strain produced only d-lactic acid from glucose and successfully expressed amyA. With the aid of secreting AmyA, direct d-lactic acid fermentation from raw corn starch was accomplished. After 48 h of fermentation, 73.2 g/liter of lactic acid was produced with a high yield (0.85 g per g of consumed sugar) and an optical purity of 99.6%. Moreover, a strain replacing the ldhL1 gene with an amyA-secreting expression cassette was constructed. Using this strain, direct d-lactic acid fermentation from raw corn starch was accomplished in the absence of selective pressure by antibiotics. This is the first report of direct d-lactic acid fermentation from raw starch. PMID:19011066

Composition analysis and application of degradation products of whole feathers through a large scale of fermentation.

PubMed

Cao, Zhang-Jun; Lu, Dan; Luo, Lai-Sheng; Deng, Yun-Xia; Bian, Yong-Gang; Zhang, Xing-Qun; Zhou, Mei-Hua

2011-08-01

Feathers are one of the most abundant bioresources. They are discarded as waste in most cases and could cause environmental pollution. On the other hand, keratin constituted by amino acids is the main component of feathers. In this article, we reported on biorefined feathers and integrants and application of degraded products. The fermentation of whole chicken feathers with Stenotrophomonas maltophilia DHHJ in a scale-up of a 5-L bioreactor was investigated in this article. The fermentation process was controlled at 0.08 MPa pressure, 2.5 L/min airflow, and 300 rpm as 100% oxygen saturation level, 40°C, and pH 7.8. Feathers were almost completely degraded in the tested fermentation reaction with the following conditions: 80 g of whole feathers in 3 L fermentation broth for 72 h, seed age of 16 h, 100 mL inoculation amount, and 50% oxygen saturation level. The degraded products contain 397.1 mg/L soluble protein that has mass weight ranging from 10 to 160 kD, 336.9 mg/L amino acids, and many kinds of metal ions. The fermentation broth was evaluated as leaf fertilizer and found to increase plant growth to 82% or 66% for two- or fourfold dilutions, respectively. In addition, in a hair care assay, the broth showed a hair protective function by increasing weight, flexibility, and strength of the treated hair. The whole feathers were degraded completely by S. maltophilia DHHJ. The degraded product includes many factors to life, such as peptides, amino acids, and mineral elements. It could be applied as leaf fertilizer and hair care product.

Global insights into acetic acid resistance mechanisms and genetic stability of Acetobacter pasteurianus strains by comparative genomics

PubMed Central

Wang, Bin; Shao, Yanchun; Chen, Tao; Chen, Wanping; Chen, Fusheng

2015-01-01

Acetobacter pasteurianus (Ap) CICC 20001 and CGMCC 1.41 are two acetic acid bacteria strains that, because of their strong abilities to produce and tolerate high concentrations of acetic acid, have been widely used to brew vinegar in China. To globally understand the fermentation characteristics, acid-tolerant mechanisms and genetic stabilities, their genomes were sequenced. Genomic comparisons with 9 other sequenced Ap strains revealed that their chromosomes were evolutionarily conserved, whereas the plasmids were unique compared with other Ap strains. Analysis of the acid-tolerant metabolic pathway at the genomic level indicated that the metabolism of some amino acids and the known mechanisms of acetic acid tolerance, might collaboratively contribute to acetic acid resistance in Ap strains. The balance of instability factors and stability factors in the genomes of Ap CICC 20001 and CGMCC 1.41 strains might be the basis for their genetic stability, consistent with their stable industrial performances. These observations provide important insights into the acid resistance mechanism and the genetic stability of Ap strains and lay a foundation for future genetic manipulation and engineering of these two strains. PMID:26691589

Biotechnological production of enantiomerically pure d-lactic acid.

PubMed

Klotz, Silvia; Kaufmann, Norman; Kuenz, Anja; Prüße, Ulf

2016-11-01

The fermentation process of l-lactic acid is well known. Little importance was attached to d-lactic acid, but in the past 10 years, d-lactic acid gained significantly in importance. d-Lactic acid is an interesting precursor for manufacturing heat-resistant polylactic acid (PLA) bioplastics which can be widely used, for example as packaging material, coatings, for textiles or in the automotive industry.This review provides a comprehensive overview of the most recent developments, including a spectrum of studied microorganisms and their capabilities for the production of d-lactic acid. Additionally, the technological achievements in biotechnological d-lactic acid production including fermentation techniques like fed batch, simultaneous saccharification, and fermentation and continuous techniques are presented. Attention is also turned to suitable alternative substrates and their applicability in fermentation processes. Furthermore, advantages and disadvantages of product recovery and purification are discussed. Economic aspects of PLA are pointed out, and the present industrial producers of lactic acid are briefly introduced.

Antimicrobial Peptides Produced by Selective Pressure Incorporation of Non-canonical Amino Acids.

PubMed

Nickling, Jessica H; Baumann, Tobias; Schmitt, Franz-Josef; Bartholomae, Maike; Kuipers, Oscar P; Friedrich, Thomas; Budisa, Nediljko

2018-05-04

Nature has a variety of possibilities to create new protein functions by modifying the sequence of the individual amino acid building blocks. However, all variations are based on the 20 canonical amino acids (cAAs). As a way to introduce additional physicochemical properties into polypeptides, the incorporation of non-canonical amino acids (ncAAs) is increasingly used in protein engineering. Due to their relatively short length, the modification of ribosomally synthesized and post-translationally modified peptides by ncAAs is particularly attractive. New functionalities and chemical handles can be generated by specific modifications of individual residues. The selective pressure incorporation (SPI) method utilizes auxotrophic host strains that are deprived of an essential amino acid in chemically defined growth media. Several structurally and chemically similar amino acid analogs can then be activated by the corresponding aminoacyl-tRNA synthetase and provide residue-specific cAA(s) → ncAA(s) substitutions in the target peptide or protein sequence. Although, in the context of the SPI method, ncAAs are also incorporated into the host proteome during the phase of recombinant gene expression, the majority of the cell's resources are assigned to the expression of the target gene. This enables efficient residue-specific incorporation of ncAAs often accompanied with high amounts of modified target. The presented work describes the in vivo incorporation of six proline analogs into the antimicrobial peptide nisin, a lantibiotic naturally produced by Lactococcus lactis. Antimicrobial properties of nisin can be changed and further expanded during its fermentation and expression in auxotrophic Escherichia coli strains in defined growth media. Thereby, the effects of residue-specific replacement of cAAs with ncAAs can deliver changes in antimicrobial activity and specificity. Antimicrobial activity assays and fluorescence microscopy are used to test the new nisin variants for growth inhibition of a Gram-positive Lactococcus lactis indicator strain. Mass spectroscopy is used to confirm ncAA incorporation in bioactive nisin variants.

Integrated production of lactic acid and biomass on distillery stillage.

PubMed

Djukić-Vuković, Aleksandra P; Mojović, Ljiljana V; Vukašinović-Sekulić, Maja S; Nikolić, Svetlana B; Pejin, Jelena D

2013-09-01

The possibilities of parallel lactic acid and biomass production in batch and fed-batch fermentation on distillery stillage from bioethanol production were studied. The highest lactic acid yield and productivity of 92.3 % and 1.49 g L(-1) h(-1) were achieved in batch fermentation with initial sugar concentration of 55 g L(-1). A significant improvement of the process was achieved in fed-batch fermentation where the concentration of lactic acid was increased to 47.6 % and volumetric productivity for 21 % over the batch process. A high number of Lactobacillus rhamnosus ATCC 7469 viable cells of 10(9) CFU ml(-1) was attained at the end of fed-batch fermentation. The survival of 92.9 % of L. rhamnosus cells after 3 h of incubation at pH 2.5 validated that the fermentation media remained after lactic acid removal could be used as a biomass-enriched animal feed thus making an additional value to the process.

Metabolomic Profiles of Aspergillus oryzae and Bacillus amyloliquefaciens During Rice Koji Fermentation.

PubMed

Lee, Da Eun; Lee, Sunmin; Jang, Eun Seok; Shin, Hye Won; Moon, Byoung Seok; Lee, Choong Hwan

2016-06-14

Rice koji, used early in the manufacturing process for many fermented foods, produces diverse metabolites and enzymes during fermentation. Using gas chromatography time-of-flight mass spectrometry (GC-TOF-MS), ultrahigh-performance liquid chromatography linear trap quadrupole ion trap tandem mass spectrometry (UHPLC-LTQ-IT-MS/MS), and multivariate analysis we generated the metabolite profiles of rice koji produced by fermentation with Aspergillus oryzae (RK_AO) or Bacillus amyloliquefaciens (RK_BA) for different durations. Two principal components of the metabolomic data distinguished the rice koji samples according to their fermenter species and fermentation time. Several enzymes secreted by the fermenter species, including α-amylase, protease, and β-glucosidase, were assayed to identify differences in expression levels. This approach revealed that carbohydrate metabolism, serine-derived amino acids, and fatty acids were associated with rice koji fermentation by A. oryzae, whereas aromatic and branched chain amino acids, flavonoids, and lysophospholipids were more typical in rice koji fermentation by B. amyloliquefaciens. Antioxidant activity was significantly higher for RK_BA than for RK_AO, as were the abundances of flavonoids, including tricin, tricin glycosides, apigenin glycosides, and chrysoeriol glycosides. In summary, we have used MS-based metabolomics and enzyme activity assays to evaluate the effects of using different microbial species and fermentation times on the nutritional profile of rice koji.

Purification, characterization and amino acid content of cholesterol oxidase produced by Streptomyces aegyptia NEAE 102.

PubMed

El-Naggar, Noura El-Ahmady; Deraz, Sahar F; Soliman, Hoda M; El-Deeb, Nehal M; El-Shweihy, Nancy M

2017-03-29

There is an increasing demand on cholesterol oxidase for its various industrial and clinical applications. The current research was focused on extracellular cholesterol oxidase production under submerged fermentation by a local isolate previously identified as Streptomyces aegyptia NEAE 102. The crude enzyme extract was purified by two purification steps, protein precipitation using ammonium sulfate followed by ion exchange chromatography using DEAE Sepharose CL-6B. The kinetic parameters of purified cholesterol oxidase from Streptomyces aegyptia NEAE 102 were studied. The best conditions for maximum cholesterol oxidase activity were found to be 105 min of incubation time, an initial pH of 7 and temperature of 37 °C. The optimum substrate concentration was found to be 0.4 mM. The higher thermal stability behavior of cholesterol oxidase was at 50 °C. Around 63.86% of the initial activity was retained by the enzyme after 20 min of incubation at 50 °C. The apparent molecular weight of the purified enzyme as sized by sodium dodecyl sulphate-polyacryalamide gel electrophoresis was approximately 46 KDa. On DEAE Sepharose CL-6B column cholesterol oxidase was purified to homogeneity with final specific activity of 16.08 U/mg protein and 3.14-fold enhancement. The amino acid analysis of the purified enzyme produced by Streptomyces aegyptia NEAE 102 illustrated that, cholesterol oxidase is composed of 361 residues with glutamic acid as the most represented amino acid with concentration of 11.49 μg/mL. Taking into account the extracellular production, wide pH tolerance, thermal stability and shelf life, cholesterol oxidase produced by Streptomyces aegyptia NEAE 102 suggested that the enzyme could be industrially useful.

Sequence Analysis of Leuconostoc mesenteroides Bacteriophage Φ1-A4 Isolated from an Industrial Vegetable Fermentation▿

PubMed Central

Lu, Z.; Altermann, E.; Breidt, F.; Kozyavkin, S.

2010-01-01

Vegetable fermentations rely on the proper succession of a variety of lactic acid bacteria (LAB). Leuconostoc mesenteroides initiates fermentation. As fermentation proceeds, L. mesenteroides dies off and other LAB complete the fermentation. Phages infecting L. mesenteroides may significantly influence the die-off of L. mesenteroides. However, no L. mesenteroides phages have been previously genetically characterized. Knowledge of more phage genome sequences may provide new insights into phage genomics, phage evolution, and phage-host interactions. We have determined the complete genome sequence of L. mesenteroides phage Φ1-A4, isolated from an industrial sauerkraut fermentation. The phage possesses a linear, double-stranded DNA genome consisting of 29,508 bp with a G+C content of 36%. Fifty open reading frames (ORFs) were predicted. Putative functions were assigned to 26 ORFs (52%), including 5 ORFs of structural proteins. The phage genome was modularly organized, containing DNA replication, DNA-packaging, head and tail morphogenesis, cell lysis, and DNA regulation/modification modules. In silico analyses showed that Φ1-A4 is a unique lytic phage with a large-scale genome inversion (∼30% of the genome). The genome inversion encompassed the lysis module, part of the structural protein module, and a cos site. The endolysin gene was flanked by two holin genes. The tail morphogenesis module was interspersed with cell lysis genes and other genes with unknown functions. The predicted amino acid sequences of the phage proteins showed little similarity to other phages, but functional analyses showed that Φ1-A4 clusters with several Lactococcus phages. To our knowledge, Φ1-A4 is the first genetically characterized L. mesenteroides phage. PMID:20118355

Using slaughterhouse waste in a biochemical-based biorefinery - results from pilot scale tests.

PubMed

Schwede, Sebastian; Thorin, Eva; Lindmark, Johan; Klintenberg, Patrik; Jääskeläinen, Ari; Suhonen, Anssi; Laatikainen, Reino; Hakalehto, Elias

2017-05-01

A novel biorefinery concept was piloted using protein-rich slaughterhouse waste, chicken manure and straw as feedstocks. The basic idea was to provide a proof of concept for the production of platform chemicals and biofuels from organic waste materials at non-septic conditions. The desired biochemical routes were 2,3-butanediol and acetone-butanol fermentation. The results showed that hydrolysis resulted only in low amounts of easily degradable carbohydrates. However, amino acids released from the protein-rich slaughterhouse waste were utilized and fermented by the bacteria in the process. Product formation was directed towards acidogenic compounds rather than solventogenic products due to increasing pH-value affected by ammonia release during amino acid fermentation. Hence, the process was not effective for 2,3-butanediol production, whereas butyrate, propionate, γ-aminobutyrate and valerate were predominantly produced. This offered fast means for converting tedious protein-rich waste mixtures into utilizable chemical goods. Furthermore, the residual liquid from the bioreactor showed significantly higher biogas production potential than the corresponding substrates. The combination of the biorefinery approach to produce chemicals and biofuels with anaerobic digestion of the residues to recover energy in form of methane and nutrients that can be utilized for animal feed production could be a feasible concept for organic waste utilization.

Effect of boiling and roasting on the fermentation of soybeans into dawadawa (soy-dawadawa).

PubMed

Dakwa, Sarah; Sakyi-Dawson, Esther; Diako, Charles; Annan, Nana Takyiwa; Amoa-Awua, Wisdom Kofi

2005-09-25

Soybeans which had initially been dehulled by either boiling (boiled/dehulled) or roasting (roasted/dehulled) before peeling, were cooked and fermented into dawadawa, a traditional food condiment. The micropopulation, enzymatic activities, proximate composition, amino acid, and aroma profiles of the two types of soybean dawadawa were evaluated during fermentation. Only minor differences were found in the microbial profiles of the two types of soy-dawadawa. Although boiled/dehulled soy-dawadawa initially had lower microbial counts, it recorded higher counts at the advanced stages of fermentation. Proteolytic and amylolytic Bacillus species including Bacillus subtilis, Bacillus pumilus, Bacillus licheniformis, Bacillus cereus, and Bacillus firmus dominated the micropopulation of the two types of soy-dawadawa with Bacillus subtilis accounting for about 50% of the Bacillus species in all samples. Lactic acid bacteria and yeasts occurred in low numbers in the two types of soy-dawadawa. The proximate composition of the two types of soy-dawadawa were similar, and their contents of moisture and protein increased whilst fat and ash decreased during fermentation. Both types of fermenting soy-dawadawa recorded similar levels of alpha-amylase activity, but boiled/dehulled soy-dawadawa showed slightly higher protease activity. The levels of isoleucine, leucine, lysine, phenylalanine, arginine and proline increased significantly with fermentation time in both types of soy-dawadawa. With respect to differences in their aroma profiles, hexanodecanol, octadecyl acetate, 1,2-dimethyl benzene, tetradecene, (E)-5-eicosene, cyclohexadecane, and hexacosane were found only in the roasted/dehulled samples, whilst 1,2-ethanediol, ethyl acetate, dimethyl disulfide, cyclotetradecane, decene, indole , 2 butyl-octenal, acetophenone, and toluene were found only in the boiled/dehulled samples. A market focus group showed preference for roasted/dehulled soy-dawadawa over boiled/dehulled soy-dawadawa. Apart from the volatile aroma compounds, the biochemical and microbiological profiles of the two types of soy-dawadawa showed only minor differences and were also similar to the profiles reported for African locust bean dawadawa.

Global insights into acetic acid resistance mechanisms and genetic stability of Acetobacter pasteurianus strains by comparative genomics

NASA Astrophysics Data System (ADS)

Wang, Bin; Shao, Yanchun; Chen, Tao; Chen, Wanping; Chen, Fusheng

2015-12-01

Acetobacter pasteurianus (Ap) CICC 20001 and CGMCC 1.41 are two acetic acid bacteria strains that, because of their strong abilities to produce and tolerate high concentrations of acetic acid, have been widely used to brew vinegar in China. To globally understand the fermentation characteristics, acid-tolerant mechanisms and genetic stabilities, their genomes were sequenced. Genomic comparisons with 9 other sequenced Ap strains revealed that their chromosomes were evolutionarily conserved, whereas the plasmids were unique compared with other Ap strains. Analysis of the acid-tolerant metabolic pathway at the genomic level indicated that the metabolism of some amino acids and the known mechanisms of acetic acid tolerance, might collaboratively contribute to acetic acid resistance in Ap strains. The balance of instability factors and stability factors in the genomes of Ap CICC 20001 and CGMCC 1.41 strains might be the basis for their genetic stability, consistent with their stable industrial performances. These observations provide important insights into the acid resistance mechanism and the genetic stability of Ap strains and lay a foundation for future genetic manipulation and engineering of these two strains.

Kinetics of D-lactic acid production by Sporolactobacillus sp. strain CASD using repeated batch fermentation.

PubMed

Zhao, Bo; Wang, Limin; Li, Fengsong; Hua, Dongliang; Ma, Cuiqing; Ma, Yanhe; Xu, Ping

2010-08-01

D-lactic acid was produced by Sporolactobacillus sp. strain CASD in repeated batch fermentation with one- and two-reactor systems. The strain showed relatively high energy consumption in its growth-related metabolism in comparison with other lactic acid producers. When the fermentation was repeated with 10% (v/v) of previous culture to start a new batch, D-lactic acid production shifted from being cell-maintenance-dependent to cell-growth-dependent. In comparison with the one-reactor system, D-lactic acid production increased approximately 9% in the fourth batch of the two-reactor system. Strain CASD is an efficient D-lactic acid producer with increased growth rate at the early stage of repeated cycles, which explains the strain's physiological adaptation to repeated batch culture and improved performance in the two-reactor fermentation system. From a kinetic point of view, two-reactor fermentation system was shown to be an alternative for conventional one-reactor repeated batch operation. Copyright 2010 Elsevier Ltd. All rights reserved.

Semicontinuous Production of Lactic Acid From Cheese Whey Using Integrated Membrane Reactor

NASA Astrophysics Data System (ADS)

Li, Yebo; Shahbazi, Abolghasem; Coulibaly, Sekou; Mims, Michele M.

Semicontinuous production of lactic acid from cheese whey using free cells of Bifidobacterium longum with and without nanofiltration was studied. For the semicontinuous fermentation without membrane separation, the lactic acid productivity of the second and third runs is much lower than the first run. The semicontinuous fermentation with nanoseparation was run semicontinuously for 72 h with lactic acid to be harvested every 24 h using a nanofiltration membrane unit. The cells and unutilized lactose were kept in the reactor and mixed with newly added cheese whey in the subsequent runs. Slight increase in the lactic acid productivity was observed in the second and third runs during the semicontinuous fermentation with nanofiltration. It can be concluded that nanoseparation could improve the lactic acid productivity of the semicontinuous fermentation process.

Global insights into acetic acid resistance mechanisms and genetic stability of Acetobacter pasteurianus strains by comparative genomics.

PubMed

Wang, Bin; Shao, Yanchun; Chen, Tao; Chen, Wanping; Chen, Fusheng

2015-12-22

Acetobacter pasteurianus (Ap) CICC 20001 and CGMCC 1.41 are two acetic acid bacteria strains that, because of their strong abilities to produce and tolerate high concentrations of acetic acid, have been widely used to brew vinegar in China. To globally understand the fermentation characteristics, acid-tolerant mechanisms and genetic stabilities, their genomes were sequenced. Genomic comparisons with 9 other sequenced Ap strains revealed that their chromosomes were evolutionarily conserved, whereas the plasmids were unique compared with other Ap strains. Analysis of the acid-tolerant metabolic pathway at the genomic level indicated that the metabolism of some amino acids and the known mechanisms of acetic acid tolerance, might collaboratively contribute to acetic acid resistance in Ap strains. The balance of instability factors and stability factors in the genomes of Ap CICC 20001 and CGMCC 1.41 strains might be the basis for their genetic stability, consistent with their stable industrial performances. These observations provide important insights into the acid resistance mechanism and the genetic stability of Ap strains and lay a foundation for future genetic manipulation and engineering of these two strains.

Revealing the beneficial effect of protease supplementation to high gravity beer fermentations using "-omics" techniques

PubMed Central

2011-01-01

Background Addition of sugar syrups to the basic wort is a popular technique to achieve higher gravity in beer fermentations, but it results in dilution of the free amino nitrogen (FAN) content in the medium. The multicomponent protease enzyme Flavourzyme has beneficial effect on the brewer's yeast fermentation performance during high gravity fermentations as it increases the initial FAN value and results in higher FAN uptake, higher specific growth rate, higher ethanol yield and improved flavour profile. Results In the present study, transcriptome and metabolome analysis were used to elucidate the effect on the addition of the multicomponent protease enzyme Flavourzyme and its influence on the metabolism of the brewer's yeast strain Weihenstephan 34/70. The study underlines the importance of sufficient nitrogen availability during the course of beer fermentation. The applied metabolome and transcriptome analysis allowed mapping the effect of the wort sugar composition on the nitrogen uptake. Conclusion Both the transcriptome and the metabolome analysis revealed that there is a significantly higher impact of protease addition for maltose syrup supplemented fermentations, while addition of glucose syrup to increase the gravity in the wort resulted in increased glucose repression that lead to inhibition of amino acid uptake and hereby inhibited the effect of the protease addition. PMID:21513553

Cofactor engineering of ketol-acid reductoisomerase (IlvC) and alcohol dehydrogenase (YqhD) improves the fusel alcohol yield in algal protein anaerobic fermentation

DOE PAGES

Wu, Weihua; Tran-Gyamfi, Mary Bao; Jaryenneh, James Dekontee; ...

2016-08-24

Recently the feasibility of conversion of algal protein to mixed alcohols has been demonstrated with an engineered E.coli strain, enabling comprehensive utilization of the biomass for biofuel applications. However, the yield and titers of mixed alcohol production must be improved for market adoption. A major limiting factor for achieving the necessary yield and titer improvements is cofactor imbalance during the fermentation of algal protein. To resolve this problem, a directed evolution approach was applied to modify the cofactor specificity of two key enzymes (IlvC and YqhD) from NADPH to NADH in the mixed alcohol metabolic pathway. Using high throughput screening,more » more than 20 YqhD mutants were identified to show activity on NADH as a cofactor. Of these 20 mutants, the top five of YqhD mutants were selected for combination with two IlvC mutants with NADH as a cofactor for the modification of the protein conversion strain. The combination of the IlvC and YqhD mutants yielded a refined E.coli strain, subtype AY3, with increased fusel alcohol yield of ~60% compared to wild type under anaerobic fermentation on amino acid mixtures. When applied to real algal protein hydrolysates, the strain AY3 produced 100% and 38% more total mixed alcohols than the wild type strain on two different algal hydrolysates, respectively. The results indicate that cofactor engineering is a promising approach to improve the feasibility of bioconversion of algal protein into mixed alcohols as advanced biofuels.« less

Semi-Continuous Fermentation of Onion Vinegar and Its Functional Properties.

PubMed

Lee, Sulhee; Lee, Jin-A; Park, Gwi-Gun; Jang, Jae-Kweon; Park, Young-Seo

2017-08-08

For the fermentation of vinegar using onion, acetic acid bacteria and yeast strains with high fermentation ability were screened. Among them, Saccharomyces cerevisiae 1026 was selected as a starter for ethanol production and Acetobacter orientalis MAK88 was selected as a vinegar producer. When the two-stage fermentation of onion vinegar was performed at 28 °C, the titratable acidity reached 4.80% at 24 h of fermentation. When semi-continuous fermentation proceeded to charge-discharge consisting of three cycles, the acetic acid content reached 4.35% at 48 h of fermentation. At this stage, the fermentation efficiency, acetic acid productivity, and specific product formation rate were 76.71%, 17.73 g/(L·d), and 20.58 g/(g·h), respectively. The process in this study significantly reduced the fermentation time and simplified the vinegar production process. The content of total flavonoids and total polyphenols in onion vinegar were 104.36 and 455.41 μg/mL, respectively. The antioxidant activities of onion vinegar in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic) acid (ABTS⁺) radical scavenging activity, and reducing power were 75.33%, 98.88%, and 1.28, respectively. The nitrite scavenging abilities of onion vinegar were 95.38 at pH 1.2. The onion vinegar produced in this study showed higher organoleptic acceptability than commercial onion vinegar.

B-535a, b and c, new sphingosine kinase inhibitors, produced by a marine bacterium; taxonomy, fermentation, isolation, physico-chemical properties and structure determination.

PubMed

Kono, K; Tanaka, M; Mizuno, T; Kodama, K; Ogita, T; Kohama, T

2000-08-01

In the course of our screening for inhibitors of sphingosine kinase, we found a series of active compounds in a culture broth of a novel marine bacterium, SANK 71896. The structures of the compounds, named B-5354a, b and c, were elucidated by a combination of spectroscopic analyses to be new esters of 4-amino-3-hydroxybenzoic acid with long-chain unsaturated alcohols. B-5354a, b and c inhibit sphingosine kinase activity with IC50 values of 21, 58 and 38 microm, respectively.

Chiral Recognition with Macrocyclic Glycopeptides: Mechanisms and Applications

NASA Astrophysics Data System (ADS)

Berthod, Alain; Qiu, Hai Xiao; Staroverov, Sergey M.; Kuznestov, Mikhail A.; Armstrong, Daniel W.

The macrocyclic glycopeptide chiral selectors are natural molecules produced by bacterial fermentation. Purified and bonded to silica particles, they make very useful chiral stationary phases (CSP) with a broad spectrum of applicability in enantiomeric separation. The macrocyclic glycopeptide CSPs are multimodal, the same column being able to work in normal phase mode with apolar mobile phase, in reversed-phase mode, or in polar ionic mode with 100% alcoholic mobile phase of adjusted pH. The role of the carbohydrate units is described as well as the critical charge-charge docking interaction responsible for the amino acid enantiomer recognition. The complimentary phenomenon is also exposed.

Removal of heavy metals from polluted soil using the citric acid fermentation broth: a promising washing agent.

PubMed

Zhang, Hongjiao; Gao, Yuntao; Xiong, Huabin

2017-04-01

The citric acid fermentation broth was prepared and it was employed to washing remediation of heavy metal-polluted soil. A well-defined washing effect was obtained, the removal percentages using citric acid fermentation broth are that 48.2% for Pb, 30.6% for Cu, 43.7% for Cr, and 58.4% for Cd and higher than that using citric acid solution. The kinetics of heavy metals desorption can be described by the double constant equation and Elovich equation and is a heterogeneous diffusion process. The speciation analysis shows that the citric acid fermentation broth can effectively reduce bioavailability and environmental risk of heavy metals. Spectroscopy characteristics analysis suggests that the washing method has only a small effect on the mineral composition and does not destroy the framework of soil system. Therefore, the citric acid fermentation broth is a promising washing agent and possesses a potential practical application value in the field of remediation of soils with a good washing performance.

Analysis of the cocobiota and metabolites of Moniliophthora perniciosa-resistant Theobroma cacao beans during spontaneous fermentation in southern Brazil.

PubMed

Bastos, Valdeci S; Santos, Maria Fs; Gomes, Laidson P; Leite, Analy Mo; Flosi Paschoalin, Vânia M; Del Aguila, Eduardo M

2018-03-25

Cocoa bean fermentation is a spontaneous process involving a succession of microbial activities, yeasts, lactic acid, and acetic acid bacteria. The spontaneous fermentation of cocoa beans by Theobroma cacao TSH565 clonal variety, a highly productive hybrid resistant to Moniliophthora perniciosa and Phytophthora spp., was investigated. The natural cocobiota involved in the spontaneous fermentation of this hybrid in southern Brazil, was investigated by using both a culture-dependent microbiological analysis and a molecular analysis. The changes in the physicochemical characteristics and the kinetics of substrate utilization and metabolite production during fermentation were also evaluated. Yeasts (178) and bacteria (244) isolated during fermentation were identified by partial sequencing of the ITS and 16S rDNAs, respectively. After 144 h of fermentation, the indigenous yeast community was composed of Hanseniaspora spp., Saccharomyces spp., and Pichia spp. The bacterial population comprised Lactococcus spp., Staphylococcus spp., Acetobacter spp. and Lactobacilli strains. The kinetics of substrate transformation reflected the dynamic composition of the cocobiota. Substrates such as glucose, fructose, sucrose, and citric acid, present at the beginning of fermentation, were metabolized to produce ethanol, acetic acid, and lactic acid. The results described here provide new insights into microbial diversity in cocoa bean-pulp mass fermentation and the kinetics of metabolites synthesis, and pave the way for the selection of starter cultures to increase efficiency and consistency to obtain homogeneous and best quality cocoa products. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Efficient calcium lactate production by fermentation coupled with crystallization-based in situ product removal.

PubMed

Xu, Ke; Xu, Ping

2014-07-01

Lactic acid is a platform chemical with various industrial applications, and its derivative, calcium lactate, is an important food additive. Fermentation coupled with in situ product removal (ISPR) can provide more outputs with high productivity. The method used in this study was based on calcium lactate crystallization. Three cycles of crystallization were performed during the fermentation course using a Bacillus coagulans strain H-1. As compared to fed-batch fermentation, this method showed 1.7 times higher average productivity considering seed culture, with 74.4% more L-lactic acid produced in the fermentation with ISPR. Thus, fermentation coupled with crystallization-based ISPR may be a biotechnological alternative that provides an efficient system for production of calcium lactate or lactic acid. Copyright © 2014 Elsevier Ltd. All rights reserved.

Electronic tongue-based discrimination of Korean rice wines (makgeolli) including prediction of sensory evaluation and instrumental measurements.

PubMed

Kang, Bo-Sik; Lee, Jang-Eun; Park, Hyun-Jin

2014-05-15

A commercial electronic tongue was used to discriminate Korean rice wines (makgeolli) brewed from nine cultivars of rice with different amino acid and fatty acid compositions. The E-tongue was applied to establish prediction models with sensory evaluation or LC-MS/MS by partial least squares regression (PLSR). All makgeollis were classified into three groups by principal components analysis, and the separation pattern was affected by rice qualities and yeast fermentation. Makgeolli taste changed from the complicated comprising sweetness, saltiness, and umami to the uncomplicated, such as bitterness and then, sourness, with a decrease of amino acids and fatty acids in the rice. The quantitative correlation between E-tongue and sensory scores or LC-MS/MS by PLSR demonstrated that E-tongue could well predict most of the sensory attributes with relatively acceptable r(2), except for bitterness, but could not predict most of the chemical compounds responsible for taste attributes, except for ribose, lactate, succinate, and tryptophan. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cofactor engineering of ketol-acid reductoisomerase (IlvC) and alcohol dehydrogenase (YqhD) improves the fusel alcohol yield in algal protein anaerobic fermentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Weihua; Tran-Gyamfi, Mary Bao; Jaryenneh, James Dekontee

Recently the feasibility of conversion of algal protein to mixed alcohols has been demonstrated with an engineered E.coli strain, enabling comprehensive utilization of the biomass for biofuel applications. However, the yield and titers of mixed alcohol production must be improved for market adoption. A major limiting factor for achieving the necessary yield and titer improvements is cofactor imbalance during the fermentation of algal protein. To resolve this problem, a directed evolution approach was applied to modify the cofactor specificity of two key enzymes (IlvC and YqhD) from NADPH to NADH in the mixed alcohol metabolic pathway. Using high throughput screening,more » more than 20 YqhD mutants were identified to show activity on NADH as a cofactor. Of these 20 mutants, the top five of YqhD mutants were selected for combination with two IlvC mutants with NADH as a cofactor for the modification of the protein conversion strain. The combination of the IlvC and YqhD mutants yielded a refined E.coli strain, subtype AY3, with increased fusel alcohol yield of ~60% compared to wild type under anaerobic fermentation on amino acid mixtures. When applied to real algal protein hydrolysates, the strain AY3 produced 100% and 38% more total mixed alcohols than the wild type strain on two different algal hydrolysates, respectively. The results indicate that cofactor engineering is a promising approach to improve the feasibility of bioconversion of algal protein into mixed alcohols as advanced biofuels.« less

Use of sourdough made with quinoa (Chenopodium quinoa) flour and autochthonous selected lactic acid bacteria for enhancing the nutritional, textural and sensory features of white bread.

PubMed

Rizzello, Carlo Giuseppe; Lorusso, Anna; Montemurro, Marco; Gobbetti, Marco

2016-06-01

Lactic acid bacteria were isolated and identified from quinoa flour, spontaneously fermented quinoa dough, and type I quinoa sourdough. Strains were further selected based on acidification and proteolytic activities. Selected Lactobacillus plantarum T6B10 and Lactobacillus rossiae T0A16 were used as mixed starter to get quinoa sourdough. Compared to non-fermented flour, organic acids, free amino acids, soluble fibers, total phenols, phytase and antioxidant activities, and in vitro protein digestibility markedly increased during fermentation. A wheat bread was made using 20% (w/w) of quinoa sourdough, and compared to baker's yeast wheat breads manufactured with or without quinoa flour. The use of quinoa sourdough improved the chemical, textural, and sensory features of wheat bread, showing better performances compared to the use of quinoa flour. Protein digestibility and quality, and the rate of starch hydrolysis were also nutritional features that markedly improved using quinoa sourdough as an ingredient. This study exploited the potential of quinoa flour through sourdough fermentation. A number of advantages encouraged the manufacture of novel and healthy leavened baked goods. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of Ultrasonic Frequency on Lactic Acid Fermentation Promotion by Ultrasonic Irradiation

NASA Astrophysics Data System (ADS)

Shimada, Tadayuki; Ohdaira, Etsuzo; Masuzawa, Nobuyoshi

2004-05-01

The authors have been researching the promotion of lactic acid fermentation by ultrasonic irradiation. In the past research, it was proven that ultrasonic irradiation is effective in the process of fermentation, and the production of yoghurt and kefir was promoted. In this study, the effect of the ultrasonic frequency in this fermentation process was examined. In the frequency range of this study, it was found that the action of fermentation promotion was exponentially proportionate to the irradiated ultrasonic frequency.

Differential regulation of mitochondrial pyruvate carrier genes modulates respiratory capacity and stress tolerance in yeast.

PubMed

Timón-Gómez, Alba; Proft, Markus; Pascual-Ahuir, Amparo

2013-01-01

Mpc proteins are highly conserved from yeast to humans and are necessary for the uptake of pyruvate at the inner mitochondrial membrane, which is used for leucine and valine biosynthesis and as a fuel for respiration. Our analysis of the yeast MPC gene family suggests that amino acid biosynthesis, respiration rate and oxidative stress tolerance are regulated by changes in the Mpc protein composition of the mitochondria. Mpc2 and Mpc3 are highly similar but functionally different: Mpc2 is most abundant under fermentative non stress conditions and important for amino acid biosynthesis, while Mpc3 is the most abundant family member upon salt stress or when high respiration rates are required. Accordingly, expression of the MPC3 gene is highly activated upon NaCl stress or during the transition from fermentation to respiration, both types of regulation depend on the Hog1 MAP kinase. Overexpression experiments show that gain of Mpc2 function leads to a severe respiration defect and ROS accumulation, while Mpc3 stimulates respiration and enhances tolerance to oxidative stress. Our results identify the regulated mitochondrial pyruvate uptake as an important determinant of respiration rate and stress resistance.

Antifungal polypeptides

DOEpatents

Altier, Daniel J [Waukee, IA; Dahlbacka, Glen [Oakland, CA; Elleskaya, Irina [Kyiv, UA; Ellanskaya, legal representative, Natalia; Herrmann, Rafael [Wilmington, DE; Hunter-Cevera, Jennie [Elliott City, MD; McCutchen, Billy F [College Station, IA; Presnail, James K [Avondale, PA; Rice, Janet A [Wilmington, DE; Schepers, Eric [Port Deposit, MD; Simmons, Carl R [Des Moines, IA; Torok, Tamas [Richmond, CA; Yalpani, Nasser [Johnston, IA

2011-04-12

Compositions and methods for protecting a plant from a pathogen, particularly a fungal pathogen, are provided. Compositions include novel amino acid sequences, and variants and fragments thereof, for antipathogenic polypeptides that were isolated from microbial fermentation broths. Nucleic acid molecules comprising nucleotide sequences that encode the antipathogenic polypeptides of the invention are also provided. A method for inducing pathogen resistance in a plant using the nucleotide sequences disclosed herein is further provided. The method comprises introducing into a plant an expression cassette comprising a promoter operably linked to a nucleotide sequence that encodes an antipathogenic polypeptide of the invention. Compositions comprising an antipathogenic polypeptide or a transformed microorganism comprising a nucleic acid of the invention in combination with a carrier and methods of using these compositions to protect a plant from a pathogen are further provided. Transformed plants, plant cells, seeds, and microorganisms comprising a nucleotide sequence that encodes an antipathogenic polypeptide of the invention, or variant or fragment thereof, are also disclosed.

Antifungal polypeptides

DOEpatents

Altier, Daniel J.; Dahlbacka, Glen; Elleskaya, Irina; Ellanskaya, legal representative; Natalia; Herrmann, Rafael; Hunter-Cevera, Jennie; McCutchen, Billy F.; Presnail, James K.; Rice, Janet A.; Schepers, Eric; Simmons, Carl R.; Torok, Tamas; Yalpani, Nasser

2010-08-10

Compositions and methods for protecting a plant from a pathogen, particularly a fungal pathogen, are provided. Compositions include novel amino acid sequences, and variants and fragments thereof, for antipathogenic polypeptides that were isolated from microbial fermentation broths. Nucleic acid molecules comprising nucleotide sequences that encode the antipathogenic polypeptides of the invention are also provided. A method for inducing pathogen resistance in a plant using the nucleotide sequences disclosed herein is further provided. The method comprises introducing into a plant an expression cassette comprising a promoter operably linked to a nucleotide sequence that encodes an antipathogenic polypeptide of the invention. Compositions comprising an antipathogenic polypeptide or a transformed microorganism comprising a nucleic acid of the invention in combination with a carrier and methods of using these compositions to protect a plant from a pathogen are further provided. Transformed plants, plant cells, seeds, and microorganisms comprising a nucleotide sequence that encodes an antipathogenic polypeptide of the invention, or variant or fragment thereof, are also disclosed.

Antifungal polypeptides

DOEpatents

Altier, Daniel J [Granger, IA; Dahlbacka, Glen [Oakland, CA; Ellanskaya, Irina [Kyiv, UA; Ellanskaya, legal representative, Natalia; Herrmann, Rafael [Wilmington, DE; Hunter-Cevera, Jennie [Elliott City, MD; McCutchen, Billy F [College Station, TX; Presnail, James K [Avondale, PA; Rice, Janet A [Wilmington, DE; Schepers, Eric [Port Deposit, MD; Simmons, Carl R [Des Moines, IA; Torok, Tamas [Richmond, CA; Yalpani, Nasser [Johnston, IA

2012-04-03

Compositions and methods for protecting a plant from a pathogen, particularly a fungal pathogen, are provided. Compositions include novel amino acid sequences, and variants and fragments thereof, for antipathogenic polypeptides that were isolated from microbial fermentation broths. Nucleic acid molecules comprising nucleotide sequences that encode the antipathogenic polypeptides of the invention are also provided. A method for inducing pathogen resistance in a plant using the nucleotide sequences disclosed herein is further provided. The method comprises introducing into a plant an expression cassette comprising a promoter operably linked to a nucleotide sequence that encodes an antipathogenic polypeptide of the invention. Compositions comprising an antipathogenic polypeptide or a transformed microorganism comprising a nucleic acid of the invention in combination with a carrier and methods of using these compositions to protect a plant from a pathogen are further provided. Transformed plants, plant cells, seeds, and microorganisms comprising a nucleotide sequence that encodes an antipathogenic polypeptide of the invention, or variant or fragment thereof, are also disclosed.

Antifungal polypeptides

DOEpatents

Altier, Daniel J.; Dahlbacka, Glen; Ellanskaya, legal representative, Natalia; Herrmann, Rafael; Hunter-Cevera, Jennie; McCutchen, Billy F.; Presnail, James K.; Rice, Janet A.; Schepers, Eric; Simmons, Carl R.; Torok, Tamas; Yalpani, Nasser; Ellanskaya, deceased, Irina

2007-12-11

Compositions and methods for protecting a plant from a pathogen, particularly a fungal pathogen, are provided. Compositions include novel amino acid sequences, and variants and fragments thereof, for antipathogenic polypeptides that were isolated from microbial fermentation broths. Nucleic acid molecules comprising nucleotide sequences that encode the antipathogenic polypeptides of the invention are also provided. A method for inducing pathogen resistance in a plant using the nucleotide sequences disclosed herein is further provided. The method comprises introducing into a plant an expression cassette comprising a promoter operably linked to a nucleotide sequence that encodes an antipathogenic polypeptide of the invention. Compositions comprising an antipathogenic polypeptide or a transformed microorganism comprising a nucleic acid of the invention in combination with a carrier and methods of using these compositions to protect a plant from a pathogen are further provided. Transformed plants, plant cells, seeds, and microorganisms comprising a nucleotide sequence that encodes an antipathogenic polypeptide of the invention, or variant or fragment thereof, are also disclosed.

Extractive fermentation for enhanced propionic acid production from lactose by Propionibacterium acidipropionici

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Z.; Yang, S.T.

1998-05-01

An extractive fermentation process using an amine extractant and a hollow-fiber membrane extractor to selectively remove propionic acid from the fermentation broth was developed to produce propionate from lactose. Compared to the conventional batch fermentation, the extractive fermentation had a much higher productivity ({approximately}1 g/(L{center_dot}h) or 5-fold increase), higher propionate yield (up to 0.66 g/g or more than 20% increase), higher final product concentration (75 g/L or higher), and higher product purity ({approximately}90%). Meanwhile, acetate and succinate productions in the extractive fermentation were significantly reduced. The improved fermentation performance can be attributed to the reduced product inhibition and a possiblemore » metabolic pathway shift to favor more propionic but less acetic and succinic acid production. The process was stable and gave consistent long-term performance over the 1.5-month period studied. The effects of propionate concentration, pH, and amine content in the solvent on the extractive fermentation were also studied and are discussed in this paper.« less

21 CFR 173.160 - Candida guilliermondii.

Code of Federal Regulations, 2010 CFR

2010-04-01

... guilliermondii may be safely used as the organism for fermentation production of citric acid in accordance with... guilliermondii and its concomitant metabolites produced during the fermentation process. (b)(1) The nonpathogenic... pure culture in the fermentation process for the production of citric acid using an acceptable aqueous...

Overexpression and optimization of glutamate decarboxylase in Lactobacillus plantarum Taj-Apis362 for high gamma-aminobutyric acid production.

PubMed

Tajabadi, Naser; Baradaran, Ali; Ebrahimpour, Afshin; Rahim, Raha A; Bakar, Fatimah A; Manap, Mohd Yazid A; Mohammed, Abdulkarim S; Saari, Nazamid

2015-07-01

Gamma-aminobutyric acid (GABA) is an important bioactive compound biosynthesized by microorganisms through decarboxylation of glutamate by glutamate decarboxylase (GAD). In this study, a full-length GAD gene was obtained by cloning the template deoxyribonucleic acid to pTZ57R/T vector. The open reading frame of the GAD gene showed the cloned gene was composed of 1410 nucleotides and encoded a 469 amino acids protein. To improve the GABA-production, the GAD gene was cloned into pMG36e-LbGAD, and then expressed in Lactobacillus plantarum Taj-Apis362 cells. The overexpression was confirmed by SDS-PAGE and GAD activity, showing a 53 KDa protein with the enzyme activity increased by sevenfold compared with the original GAD activity. The optimal fermentation conditions for GABA production established using response surface methodology were at glutamic acid concentration of 497.973 mM, temperature 36°C, pH 5.31 and time 60 h. Under the conditions, maximum GABA concentration obtained (11.09 mM) was comparable with the predicted value by the model at 11.23 mM. To our knowledge, this is the first report of successful cloning (clone-back) and overexpression of the LbGAD gene from L. plantarum to L. plantarum cells. The recombinant Lactobacillus could be used as a starter culture for direct incorporation into a food system during fermentation for production of GABA-rich products. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Producing Acetic Acid of Acetobacter pasteurianus by Fermentation Characteristics and Metabolic Flux Analysis.

PubMed

Wu, Xuefeng; Yao, Hongli; Liu, Qing; Zheng, Zhi; Cao, Lili; Mu, Dongdong; Wang, Hualin; Jiang, Shaotong; Li, Xingjiang

2018-03-19

The acetic acid bacterium Acetobacter pasteurianus plays an important role in acetic acid fermentation, which involves oxidation of ethanol to acetic acid through the ethanol respiratory chain under specific conditions. In order to obtain more suitable bacteria for the acetic acid industry, A. pasteurianus JST-S screened in this laboratory was compared with A. pasteurianus CICC 20001, a current industrial strain in China, to determine optimal fermentation parameters under different environmental stresses. The maximum total acid content of A. pasteurianus JST-S was 57.14 ± 1.09 g/L, whereas that of A. pasteurianus CICC 20001 reached 48.24 ± 1.15 g/L in a 15-L stir stank. Metabolic flux analysis was also performed to compare the reaction byproducts. Our findings revealed the potential value of the strain in improvement of industrial vinegar fermentation.

Biodiversity of yeasts, lactic acid bacteria and acetic acid bacteria in the fermentation of "Shanxi aged vinegar", a traditional Chinese vinegar.

PubMed

Wu, Jia Jia; Ma, Ying Kun; Zhang, Fen Fen; Chen, Fu Sheng

2012-05-01

Shanxi aged vinegar is a famous traditional Chinese vinegar made from several kinds of cereal by spontaneous solid-state fermentation techniques. In order to get a comprehensive understanding of culturable microorganism's diversity present in its fermentation, the indigenous microorganisms including 47 yeast isolates, 28 lactic acid bacteria isolates and 58 acetic acid bacteria isolates were recovered in different fermenting time and characterized based on a combination of phenotypic and genotypic approaches including inter-delta/PCR, PCR-RFLP, ERIC/PCR analysis, as well as 16S rRNA and 26S rRNA partial gene sequencing. In the alcoholic fermentation, the dominant yeast species Saccharomyces (S.) cerevisiae (96%) exhibited low phenotypic and genotypic diversity among the isolates, while Lactobacillus (Lb.) fermentum together with Lb. plantarum, Lb. buchneri, Lb. casei, Pediococcus (P.) acidilactici, P. pentosaceus and Weissella confusa were predominated in the bacterial population at the same stage. Acetobacter (A.) pasteurianus showing great variety both in genotypic and phenotypic tests was the dominant species (76%) in the acetic acid fermentation stage, while the other acetic acid bacteria species including A. senegalensis, A. indonesiensis, A. malorum and A. orientalis, as well as Gluconobacter (G.) oxydans were detected at initial point of alcoholic and acetic acid fermentation stage respectively. Copyright © 2011 Elsevier Ltd. All rights reserved.

Production of butyric acid from acid hydrolysate of corn husk in fermentation by Clostridium tyrobutyricum: kinetics and process economic analysis.

PubMed

Xiao, Zhiping; Cheng, Chu; Bao, Teng; Liu, Lujie; Wang, Bin; Tao, Wenjing; Pei, Xun; Yang, Shang-Tian; Wang, Minqi

2018-01-01

Butyric acid is an important chemical currently produced from petrochemical feedstocks. Its production from renewable, low-cost biomass in fermentation has attracted large attention in recent years. In this study, the feasibility of corn husk, an abundant agricultural residue, for butyric acid production by using Clostridium tyrobutyricum immobilized in a fibrous bed bioreactor (FBB) was evaluated. Hydrolysis of corn husk (10% solid loading) with 0.4 M H 2 SO 4 at 110 °C for 6 h resulted in a hydrolysate containing ~ 50 g/L total reducing sugars (glucose:xylose = 1.3:1.0). The hydrolysate was used for butyric acid fermentation by C. tyrobutyricum in a FBB, which gave 42.6 and 53.0% higher butyric acid production from glucose and xylose, respectively, compared to free-cell fermentations. Fermentation with glucose and xylose mixture (1:1) produced 50.37 ± 0.04 g L -1 butyric acid with a yield of 0.38 ± 0.02 g g -1 and productivity of 0.34 ± 0.03 g L -1  h -1 . Batch fermentation with corn husk hydrolysate produced 21.80 g L -1 butyric acid with a yield of 0.39 g g -1 , comparable to those from glucose. Repeated-batch fermentations consistently produced 20.75 ± 0.65 g L -1 butyric acid with an average yield of 0.39 ± 0.02 g g -1 in three consecutive batches. An extractive fermentation process can be used to produce, separate, and concentrate butyric acid to > 30% (w/v) sodium butyrate at an economically attractive cost for application as an animal feed supplement. A high concentration of total reducing sugars at ~ 50% (w/w) yield was obtained from corn husk after acid hydrolysis. Stable butyric acid production from corn husk hydrolysate was achieved in repeated-batch fermentation with C. tyrobutyricum immobilized in a FBB, demonstrating that corn husk can be used as an economical substrate for butyric acid production.

Time-based comparative transcriptomics in engineered xylose-utilizing Saccharomyces cerevisiae identifies temperature-responsive genes during ethanol production.

PubMed

Ismail, Ku Syahidah Ku; Sakamoto, Takatoshi; Hasunuma, Tomohisa; Kondo, Akihiko

2013-09-01

Agricultural residues comprising lignocellulosic materials are excellent sources of pentose sugar, which can be converted to ethanol as fuel. Ethanol production via consolidated bioprocessing requires a suitable microorganism to withstand the harsh fermentation environment of high temperature, high ethanol concentration, and exposure to inhibitors. We genetically enhanced an industrial Saccharomyces cerevisiae strain, sun049, enabling it to uptake xylose as the sole carbon source at high fermentation temperature. This strain was able to produce 13.9 g/l ethanol from 50 g/l xylose at 38 °C. To better understand the xylose consumption ability during long-term, high-temperature conditions, we compared by transcriptomics two fermentation conditions: high temperature (38 °C) and control temperature (30 °C) during the first 12 h of fermentation. This is the first long-term, time-based transcriptomics approach, and it allowed us to discover the role of heat-responsive genes when xylose is the sole carbon source. The results suggest that genes related to amino acid, cell wall, and ribosomal protein synthesis are down-regulated under heat stress. To allow cell stability and continuous xylose uptake in order to produce ethanol, hexose transporter HXT5, heat shock proteins, ubiquitin proteins, and proteolysis were all induced at high temperature. We also speculate that the strong relationship between high temperature and increased xylitol accumulation represents the cell's mechanism to protect itself from heat degradation.

Overexpression of Human Bone Alkaline Phosphatase in Pichia Pastoris

NASA Technical Reports Server (NTRS)

Karr, Laurel; Malone, Christine, C.; Rose, M. Franklin (Technical Monitor)

2000-01-01

The Pichiapastoris expression system was utilized to produce functionally active human bone alkaline phosphatase in gram quantities. Bone alkaline phosphatase is a key enzyme in bone formation and biomineralization, yet important questions about its structural chemistry and interactions with other cellular enzymes in mineralizing tissues remain unanswered. A soluble form of human bone alkaline phosphatase was constructed by deletion of the 25 amino acid hydrophobic C-terminal region of the encoding cDNA and inserted into the X-33 Pichiapastoris strain. An overexpression system was developed in shake flasks and converted to large-scale fermentation. Alkaline phosphatase was secreted into the medium to a level of 32mgAL when cultured in shake flasks. Enzyme activity was 12U/mg measured by a spectrophotometric assay. Fermentation yielded 880mgAL with enzymatic activity of 968U/mg. Gel electrophoresis analysis indicates that greater than 50% of the total protein in the fermentation is alkaline phosphatase. A purification scheme has been developed using ammonium sulfate precipitation followed by hydrophobic interaction chromatography. We are currently screening crystallization conditions of the purified recombinant protein for subsequent X-ray diffraction analyses. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

Capillary electrophoresis method for the analysis of organic acids and amino acids in the presence of strongly alternating concentrations of aqueous lactic acid.

PubMed

Laube, Hendrik; Boden, Jana; Schneider, Roland

2017-07-01

During the production of bio-based bulk chemicals, such as lactic acid (LA), organic impurities have to be removed to produce a ready-to-market product. A capillary electrophoresis method for the simultaneous detection of LA and organic impurities in less than 10 min was developed. LA and organic impurities were detected using a direct UV detection method with micellar background electrolyte, which consisted of borate and sodium dodecyl sulfate. We investigated the effects of electrolyte composition and temperature on the speed, sensitivity, and robustness of the separation. A few validation parameters, such as linearity, limit of detection, and internal and external standards, were evaluated under optimized conditions. The method was applied for the detection of LA and organic impurities, including tyrosine, phenylalanine, and pyroglutamic acid, in samples from a continuous LA fermentation process from post-extraction tapioca starch and yeast extract.

A novel extractive fermentation process for propionic acid production from whey lactose

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lewis, V.P.; Yang, Shangtian

An extractive fermentation process was developed to produce propionate from lactose. The bacterium Propionibacterium acidipropionici was immobilized in a spiral wound, fibrous matrix packed in the reactor. Propionic acid is the major product from lactose fermentation, with acetic acid and carbon dioxide as byproducts. Propionic acid is a strong inhibitor to this fermentation. A tertiary amine was used to selectively extract propionic acid from the bioreactor, hence enhancing reactor productivity by over 100%. The authors also speculate that by selectively extracting propionic acid, lactose metabolism can be directed to yield more propionate and less byproducts. Other advantages of extractive fermentationmore » include better pH control and a purer product. The propionic acid present in the extractant can be easily stripped with small amounts of an alkaline solution, resulting in a concentrated propionate salt. The extractant was also regenerated in this stripping step. Thus, the process is energy-efficient and economically attractive.« less

Rapid discrimination of strain-dependent fermentation characteristics among Lactobacillus strains by NMR-based metabolomics of fermented vegetable juice

PubMed Central

Nakamura, Toshihide; Sekiyama, Yasuyo; Kikuchi, Jun

2017-01-01

In this study, we investigated the applicability of NMR-based metabolomics to discriminate strain-dependent fermentation characteristics of lactic acid bacteria (LAB), which are important microorganisms for fermented food production. To evaluate the discrimination capability, six type strains of Lactobacillus species and six additional L. brevis strains were used focusing on i) the difference between homo- and hetero-lactic fermentative species and ii) strain-dependent characteristics within L. brevis. Based on the differences in the metabolite profiles of fermented vegetable juices, non-targeted principal component analysis (PCA) clearly separated the samples into those inoculated with homo- and hetero-lactic fermentative species. The separation was primarily explained by the different levels of dominant metabolites (lactic acid, acetic acid, ethanol, and mannitol). Orthogonal partial least squares discrimination analysis, based on a regions-of-interest (ROIs) approach, revealed the contribution of low-abundance metabolites: acetoin, phenyllactic acid, p-hydroxyphenyllactic acid, glycerophosphocholine, and succinic acid for homolactic fermentation; and ornithine, tyramine, and γ-aminobutyric acid (GABA) for heterolactic fermentation. Furthermore, ROIs-based PCA of seven L. brevis strains separated their strain-dependent fermentation characteristics primarily based on their ability to utilize sucrose and citric acid, and convert glutamic acid and tyrosine into GABA and tyramine, respectively. In conclusion, NMR metabolomics successfully discriminated the fermentation characteristics of the tested strains and provided further information on metabolites responsible for these characteristics, which may impact the taste, aroma, and functional properties of fermented foods. PMID:28759594

Application of low-cost algal nitrogen source feeding in fuel ethanol production using high gravity sweet potato medium.

PubMed

Shen, Yu; Guo, Jin-Song; Chen, You-Peng; Zhang, Hai-Dong; Zheng, Xu-Xu; Zhang, Xian-Ming; Bai, Feng-Wu

2012-08-31

Protein-rich bloom algae biomass was employed as nitrogen source in fuel ethanol fermentation using high gravity sweet potato medium containing 210.0 g l(-1) glucose. In batch mode, the fermentation could not accomplish even in 120 h without any feeding of nitrogen source. While, the feeding of acid-hydrolyzed bloom algae powder (AHBAP) notably promoted fermentation process but untreated bloom algae powder (UBAP) was less effective than AHBAP. The fermentation times were reduced to 96, 72, and 72 h if 5.0, 10.0, and 20.0 g l(-1) AHBAP were added into medium, respectively, and the ethanol yields and productivities increased with increasing amount of feeding AHBAP. The continuous fermentations were performed in a three-stage reactor system. Final concentrations of ethanol up to 103.2 and 104.3 g l(-1) with 4.4 and 5.3 g l(-1) residual glucose were obtained using the previously mentioned medium feeding with 20.0 and 30.0 g l(-1) AHBAP, at dilution rate of 0.02 h(-1). Notably, only 78.5 g l(-1) ethanol and 41.6 g l(-1) residual glucose were obtained in the comparative test without any nitrogen source feeding. Amino acids analysis showed that approximately 67% of the protein in the algal biomass was hydrolyzed and released into the medium, serving as the available nitrogen nutrition for yeast growth and metabolism. Both batch and continuous fermentations showed similar fermentation parameters when 20.0 and 30.0 g l(-1) AHBAP were fed, indicating that the level of available nitrogen in the medium should be limited, and an algal nitrogen source feeding amount higher than 20.0 g l(-1) did not further improve the fermentation performance. Copyright © 2012 Elsevier B.V. All rights reserved.

Microbial process for the preparation of acetic acid, as well as solvent for its extraction from the fermentation broth

DOEpatents

Gaddy, James L.; Clausen, Edgar C.; Ko, Ching-Whan; Wade, Leslie E.; Wikstrom, Carl V.

2004-06-22

A modified water-immiscible solvent useful in the extraction of acetic acid from aqueous streams is a substantially pure mixture of isomers of highly branched di-alkyl amines. Solvent mixtures formed of such a modified solvent with a desired co-solvent, preferably a low boiling hydrocarbon, are useful in the extraction of acetic acid from aqueous gaseous streams. An anaerobic microbial fermentation process for the production of acetic acid employs such solvents, under conditions which limit amide formation by the solvent and thus increase the efficiency of acetic acid recovery. Methods for the direct extraction of acetic acid and the extractive fermentation of acetic acid also employ the modified solvents and increase efficiency of acetic acid production. Such increases in efficiency are also obtained where the energy source for the microbial fermentation contains carbon dioxide and the method includes a carbon dioxide stripping step prior to extraction of acetic acid in solvent.

Microbial process for the preparation of acetic acid, as well as solvent for its extraction from the fermentation broth

DOEpatents

Gaddy, James L.; Clausen, Edgar C.; Ko, Ching-Whan; Wade, Leslie E.; Wikstrom, Carl V.

2007-03-27

A modified water-immiscible solvent useful in the extraction of acetic acid from aqueous streams is a substantially pure mixture of isomers of highly branched di-alkyl amines. Solvent mixtures formed of such a modified solvent with a desired co-solvent, preferably a low boiling hydrocarbon, are useful in the extraction of acetic acid from aqueous gaseous streams. An anaerobic microbial fermentation process for the production of acetic acid employs such solvents, under conditions which limit amide formation by the solvent and thus increase the efficiency of acetic acid recovery. Methods for the direct extraction of acetic acid and the extractive fermentation of acetic acid also employ the modified solvents and increase efficiency of acetic acid production. Such increases in efficiency are also obtained where the energy source for the microbial fermentation contains carbon dioxide and the method includes a carbon dioxide stripping step prior to extraction of acetic acid in solvent.

Ethanol and lactic acid production using sap squeezed from old oil palm trunks felled for replanting.

PubMed

Kosugi, Akihiko; Tanaka, Ryohei; Magara, Kengo; Murata, Yoshinori; Arai, Takamitsu; Sulaiman, Othman; Hashim, Rokiah; Hamid, Zubaidah Aimi Abdul; Yahya, Mohd Khairul Azri; Yusof, Mohd Nor Mohd; Ibrahim, Wan Asma; Mori, Yutaka

2010-09-01

Old oil palm trunks that had been felled for replanting were found to contain large quantities of high glucose content sap. Notably, the sap in the inner part of the trunk accounted for more than 80% of the whole trunk weight. The glucose concentration of the sap from the inner part was 85.2g/L and decreased towards the outer part. Other sugars found in relatively low concentrations were sucrose, fructose, galactose, xylose, and rhamnose. In addition, oil palm sap was found to be rich in various kinds of amino acids, organic acids, minerals and vitamins. Based on these findings, we fermented the sap to produce ethanol using the sake brewing yeast strain, Saccharomyces cerevisiae Kyokai no.7. Ethanol was produced from the sap without the addition of nutrients, at a comparable rate and yield to the reference fermentation on YPD medium with glucose as a carbon source. Likewise, we produced lactic acid, a promising material for bio-plastics, poly-lactate, from the sap using the homolactic acid bacterium Lactobacillus lactis ATCC19435. We confirmed that sugars contained in the sap were readily converted to lactic acid with almost the same efficiency as the reference fermentation on MSR medium with glucose as a substrate. These results indicate that oil palm trunks felled for replanting are a significant resource for the production of fuel ethanol and lactic acid in palm oil-producing countries such as Malaysia and Indonesia. Copyright 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Prediction of reaction knockouts to maximize succinate production by Actinobacillus succinogenes

DOE PAGES

Nag, Ambarish; St. John, Peter C.; Crowley, Michael F.; ...

2018-01-30

Succinate is a precursor of multiple commodity chemicals and bio-based succinate production is an active area of industrial bioengineering research. One of the most important microbial strains for bio-based production of succinate is the capnophilic gram-negative bacterium Actinobacillus succinogenes, which naturally produces succinate by a mixed-acid fermentative pathway. To engineer A. succinogenes to improve succinate yields during mixed acid fermentation, it is important to have a detailed understanding of the metabolic flux distribution in A. succinogenes when grown in suitable media. To this end, we have developed a detailed stoichiometric model of the A. succinogenes central metabolism that includes themore » biosynthetic pathways for the main components of biomass - namely glycogen, amino acids, DNA, RNA, lipids and UDP-N-Acetyl-a-D-glucosamine. We have validated our model by comparing model predictions generated via flux balance analysis with experimental results on mixed acid fermentation. Moreover, we have used the model to predict single and double reaction knockouts to maximize succinate production while maintaining growth viability. According to our model, succinate production can be maximized by knocking out either of the reactions catalyzed by the PTA (phosphate acetyltransferase) and ACK (acetyl kinase) enzymes, whereas the double knockouts of PEPCK (phosphoenolpyruvate carboxykinase) and PTA or PEPCK and ACK enzymes are the most effective in increasing succinate production.« less

Enhancement of γ-aminobutyric acid production in recombinant Corynebacterium glutamicum by co-expressing two glutamate decarboxylase genes from Lactobacillus brevis.

PubMed

Shi, Feng; Jiang, Junjun; Li, Yongfu; Li, Youxin; Xie, Yilong

2013-11-01

γ-Aminobutyric acid (GABA), a non-protein amino acid, is a bioactive component in the food, feed and pharmaceutical fields. To establish an effective single-step production system for GABA, a recombinant Corynebacterium glutamicum strain co-expressing two glutamate decarboxylase (GAD) genes (gadB1 and gadB2) derived from Lactobacillus brevis Lb85 was constructed. Compared with the GABA production of the gadB1 or gadB2 single-expressing strains, GABA production by the gadB1-gadB2 co-expressing strain increased more than twofold. By optimising urea supplementation, the total production of L-glutamate and GABA increased from 22.57 ± 1.24 to 30.18 ± 1.33 g L⁻¹, and GABA production increased from 4.02 ± 0.95 to 18.66 ± 2.11 g L⁻¹ after 84-h cultivation. Under optimal urea supplementation, L-glutamate continued to be consumed, GABA continued to accumulate after 36 h of fermentation, and the pH level fluctuated. GABA production increased to a maximum level of 27.13 ± 0.54 g L⁻¹ after 120-h flask cultivation and 26.32 g L⁻¹ after 60-h fed-batch fermentation. The conversion ratio of L-glutamate to GABA reached 0.60-0.74 mol mol⁻¹. By co-expressing gadB1 and gadB2 and optimising the urea addition method, C. glutamicum was genetically improved for de novo biosynthesis of GABA from its own accumulated L-glutamate.

Metaproteomics analysis of the functional insights into microbial communities of combined hydrogen and methane production by anaerobic fermentation from reed straw

PubMed Central

Yang, Yang; Wang, Yong

2017-01-01

A metaproteomic approach was used to analyse the proteins expressed and provide functional evidence of key metabolic pathways in the combined production of hydrogen and methane by anaerobic fermentation (CHMP-AF) for reed straw utilisation. The functions and structures of bacteria and archaea populations show significant succession in the CHMP-AF process. There are many kinds of bacterial functional proteins, mainly belonging to phyla Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes, that are involved in carbohydrate metabolism, energy metabolism, lipid metabolism, and amino acid metabolism. Ferredoxin-NADP reductase, present in bacteria in genus Azotobacter, is an important enzyme for NADH/NAD+ equilibrium regulation in hydrogen production. The archaeal functional proteins are mainly involved in methane metabolism in energy metabolism, such as acetyl-CoA decarboxylase, and methyl-coenzyme M reductase, and the acetic acid pathway exhibited the highest proportion of the total. The archaea of genus Methanosarcina in phylum Euryarchaeota can produce methane under the effect of multi-functional proteins through acetic acid, CO2 reduction, and methyl nutrient pathways. The study demonstrates metaproteomics as a new way of uncovering community functional and metabolic activity. The combined information was used to identify the metabolic pathways and organisms crucial for lignocellulosic biomass degradation and biogas production. This also regulates the process from its protein levels and improves the efficiency of biogas production using reed straw biomass. PMID:28817657

By-products from the biodiesel chain as a substrate to citric acid production by solid-state fermentation.

PubMed

Schneider, Manuella; Zimmer, Gabriela F; Cremonese, Ezequiel B; de C de S Schneider, Rosana; Corbellini, Valeriano A

2014-07-01

In this study, we propose the use of tung cake for the production of organic acids, with an emphasis on citric acid by solid-state fermentation. We evaluated the conditions of production and the by-products from the biodiesel chain as raw materials involved in this bioprocess. First, we standardized the conditions of solid-state fermentation in tung cake with and without residual fat and with different concentrations of glycerine using the fungus Aspergillus niger The solid-state fermentation process was monitored for 7 days considering the biomass growth and pH level. Citric acid production was determined by high-performance liquid chromatography. Fungal development was better in the crude tung cake, consisting of 20% glycerine. The highest citric acid yield was 350 g kg(-1) of biomass. Therefore, the solid-state fermentation of the tung cake with glycerine led to citric acid production using the Aspergillus niger fungus. © The Author(s) 2014.

Metaproteomics analysis of the functional insights into microbial communities of combined hydrogen and methane production by anaerobic fermentation from reed straw.

PubMed

Jia, Xuan; Xi, Bei-Dou; Li, Ming-Xiao; Yang, Yang; Wang, Yong

2017-01-01

A metaproteomic approach was used to analyse the proteins expressed and provide functional evidence of key metabolic pathways in the combined production of hydrogen and methane by anaerobic fermentation (CHMP-AF) for reed straw utilisation. The functions and structures of bacteria and archaea populations show significant succession in the CHMP-AF process. There are many kinds of bacterial functional proteins, mainly belonging to phyla Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes, that are involved in carbohydrate metabolism, energy metabolism, lipid metabolism, and amino acid metabolism. Ferredoxin-NADP reductase, present in bacteria in genus Azotobacter, is an important enzyme for NADH/NAD+ equilibrium regulation in hydrogen production. The archaeal functional proteins are mainly involved in methane metabolism in energy metabolism, such as acetyl-CoA decarboxylase, and methyl-coenzyme M reductase, and the acetic acid pathway exhibited the highest proportion of the total. The archaea of genus Methanosarcina in phylum Euryarchaeota can produce methane under the effect of multi-functional proteins through acetic acid, CO2 reduction, and methyl nutrient pathways. The study demonstrates metaproteomics as a new way of uncovering community functional and metabolic activity. The combined information was used to identify the metabolic pathways and organisms crucial for lignocellulosic biomass degradation and biogas production. This also regulates the process from its protein levels and improves the efficiency of biogas production using reed straw biomass.

Comparison of high-titer lactic acid fermentation from NaOH- and NH3-H2O2-pretreated corncob by Bacillus coagulans using simultaneous saccharification and fermentation

PubMed Central

Zhang, Zhenting; Xie, Yuejiao; He, Xiaolan; Li, Xinli; Hu, Jinlong; Ruan, Zhiyong; Zhao, Shumiao; Peng, Nan; Liang, Yunxiang

2016-01-01

Lignocellulose is one of the most abundant renewable feedstocks that has attracted considerable attention as a substrate for biofuel and biochemical production. One such biochemical product, lactic acid, is an important fermentation product because of its great potential for the production of biodegradable and biocompatible polylactic acid. High-titer lactic acid production from lignocellulosic materials has been achieved recently; however, it requires biodetoxification or results in large amounts of waste washing water. In this study, we employed two alkaline pretreatment methods and compared their effects on lactic acid fermentation of pretreated corncob by Bacillus coagulans LA204 using fed-batch simultaneous saccharification and fermentation under non-sterile conditions. The lactic acid titer, yield, and productivity from 16% (w/w) NaOH-pretreated and washed corncob were 122.99 g/L, 0.77 g/g corncob, and 1.37 g/L/h, respectively, and from 16% NH3-H2O2-pretreated and washed corncob were 118.60 g/L, 0.74 g/g corncob, and 1.32 g/L/h, respectively. Importantly, the lactic acid titer, yield, and productivity from 18.4% NH3-H2O2-pretreated and unwashed corncob by using fed-batch simultaneous saccharification and fermentation reached 79.47 g/L, 0.43 g/g corncob, and 1.10 g/L/h, respectively, demonstrating that this method is possible for industrial applications and saves washing water. PMID:27853308

A lignocellulosic hydrolysate-tolerant Aurantiochytrium sp. mutant strain for docosahexaenoic acid production.

PubMed

Qi, Feng; Zhang, Mingliang; Chen, Youwei; Jiang, Xianzhang; Lin, Jinxin; Cao, Xiao; Huang, Jianzhong

2017-03-01

To utilize lignocellulosic hydrolysate for docosahexaenoic acid (DHA) production, a novel mutant Aurantiochytrium sp. FN21 with strong tolerance against inhibitory lignocellulosic hydrolysate was obtained through continuous domestication processes from the parent strain Aurantiochytrium sp. FJU-512. Aurantiochytrium sp. FN21 can accumulate 21.3% and 30.7% more DHA compared to its parent strain cultured in fermentation medium and a medium with 50% (v/v) sugarcane bagasse hydrolysate (SBH), respectively. After optimization with different nitrogen sources, the highest lipid (11.84g/L) and DHA (3.15g/L) production were achieved in SBH. The results demonstrated that Aurantiochytrium sp. FN21 has the commercial applications for DHA production using lignocellulosic hydrolysate. In order to elucidate the tolerance mechanism, transcriptomic profiling of the two strains was studied. The highly up-regulated genes and corresponding cellular pathways (TCA cycle, amino acid biosynthesis, fatty acid metabolism and degradation of aromatic compounds) are considered to be associated with the hydrolysate-tolerance of Aurantiochytrium sp. FN21. Copyright © 2016 Elsevier Ltd. All rights reserved.

Intracellular metabolic changes of Clostridium acetobutylicum and promotion to butanol tolerance during biobutanol fermentation.

PubMed

Wang, Yan-Feng; Tian, Juan; Ji, Zhi-Hua; Song, Mao-Yong; Li, Hao

2016-09-01

During the fermentation process, Clostridium acetobutylicum cells are often inhibited by the accumulated butanol. However, the mechanism underlying response of C. acetobutylicum to butanol stress remains poorly understood. This study was performed to clarify such mechanism through investigating the butanol stress-associated intracellular biochemical changes at acidogenesis phase (i.e., middle exponential phase) and solventogenesis phase (i.e., early stationary phase) by a gas chromatography-mass spectrometry-based metabolomics strategy. With the aid of partial least-squares-discriminant analysis, a pairwise discrimination between control group and butanol-treated groups was revealed, and 27 metabolites with variable importance in the projection value greater than 1 were identified. Under butanol stress, the glycolysis might be inhibited while TCA cycle might be promoted. Moreover, changes of lipids and fatty acids compositions, amino acid metabolism and osmoregulator concentrations might be the key factors involved in C. acetobutylicum metabolic response to butanol stress. It was suggested that C. acetobutylicum cells might change the levels of long acyl chain saturated fatty acids and branched-chain amino acids to maintain the integrity of cell membrane through adjusting membrane fluidity under butanol stress. The increased level of glycerol was considered to be correlated with osmoregulation and regulating redox balance. In addition, increased levels of some amino acids (i.e., threonine, glycine, alanine, phenylalanine, tyrosine, tryptophan, aspartate and glutamate) might also confer butanol tolerance to C. acetobutylicum. These results highlighted our knowledge about the response or adaptation of C. acetobutylicum to butanol stress, and would contribute to the construction of feasible butanologenic strains with higher butanol tolerance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Prediction of reaction knockouts to maximize succinate production by Actinobacillus succinogenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nag, Ambarish; St. John, Peter C.; Crowley, Michael F.

Succinate is a precursor of multiple commodity chemicals and bio-based succinate production is an active area of industrial bioengineering research. One of the most important microbial strains for bio-based production of succinate is the capnophilic gram-negative bacterium Actinobacillus succinogenes, which naturally produces succinate by a mixed-acid fermentative pathway. To engineer A. succinogenes to improve succinate yields during mixed acid fermentation, it is important to have a detailed understanding of the metabolic flux distribution in A. succinogenes when grown in suitable media. To this end, we have developed a detailed stoichiometric model of the A. succinogenes central metabolism that includes themore » biosynthetic pathways for the main components of biomass - namely glycogen, amino acids, DNA, RNA, lipids and UDP-N-Acetyl-a-D-glucosamine. We have validated our model by comparing model predictions generated via flux balance analysis with experimental results on mixed acid fermentation. Moreover, we have used the model to predict single and double reaction knockouts to maximize succinate production while maintaining growth viability. According to our model, succinate production can be maximized by knocking out either of the reactions catalyzed by the PTA (phosphate acetyltransferase) and ACK (acetyl kinase) enzymes, whereas the double knockouts of PEPCK (phosphoenolpyruvate carboxykinase) and PTA or PEPCK and ACK enzymes are the most effective in increasing succinate production.« less

Use of Lactobacillus plantarum fermentation products in bread-making to prevent Bacillus subtilis ropy spoilage.

PubMed

Valerio, Francesca; De Bellis, Palmira; Lonigro, Stella L; Visconti, Angelo; Lavermicocca, Paola

2008-03-20

Four fermentation products (FPs) of the lactic acid bacterium Lactobacillus plantarum ITM21B were screened for their anti-Bacillus activity in vitro and in bread-making trials. Results of the storage tests performed with loaves prepared with an FP or calcium propionate demonstrated that after 3 days at 30 degrees C, gross spoilage was evident in only the control loaves, which contained Bacillus subtilis at numbers of about 10(9) cfu/g. The highest inhibitory activity was shown by DM-FP obtained by growing L. plantarum in a defined medium (DM). Significantly, this medium contained an amino acceptor of the aminoacid transamination, namely alpha-ketoglutaric acid, and an aminoacid pool. With loaves prepared using the DM-acid mixture which simulated the DM-FP composition, the same reduction of ropy spoilage as with DM-FP was obtained after 3 days, while the efficacy of the mixture decreased after 7 days. This result suggests the potential involvement of some unknown metabolites in the inhibitory activity of DM-FP. In baked products made with flour based media (M1-FP, M2-FP, M3-FP), no ropy symptoms were noticeable after 3 days storage although a considerable Bacillus count was detected. DM-FP was as effective as calcium propionate (0.3% w/w, based on flour mass) in prolonging the Bacillus free-shelf life of yeast-leavened bread for 7 days.

[Modeling of lactic acid fermentation of leguminous plant juices].

PubMed

Shurkhno, R A; Validov, Sh Z; Boronin, A M; Naumova, R P

2006-01-01

Lactic acid fermentation of leguminous plant juices was modeled to provide a comparative efficiency assessment of the previously selected strains of lactic acid bacteria as potential components of starter cultures. Juices of the legumes fodder galega, red clover, and alfalfa were subjected to lactic acid fermentation in 27 variants of experiment. Local strains (Lactobacillus sp. RS 2, Lactobacillus sp. RS 3, and Lactobacillus sp. RS 4) and the collection strain Lactobacillus plantarum BS 933 appeared the most efficient (with reference to the rate and degree of acidogenesis, ratio of lactic and acetic acids, and dynamics of microflora) in fermenting fodder galega juice; Lactobacillus sp. RS 1, Lactobacillus sp. RS 2, Lactobacillus sp. RS 3, Lactobacillus sp. RS 4, and L. plantarum BS 933 were the most efficient for red clover juice. Correction of alfalfa juice fermentation using the tested lactic acid bacterial strains appeared inefficient, which is explainable by its increased protein content and a low level of the acids produced during fermentation.

Economically enhanced succinic acid fermentation from cassava bagasse hydrolysate using Corynebacterium glutamicum immobilized in porous polyurethane filler.

PubMed

Shi, Xinchi; Chen, Yong; Ren, Hengfei; Liu, Dong; Zhao, Ting; Zhao, Nan; Ying, Hanjie

2014-12-01

An immobilized fermentation system, using cassava bagasse hydrolysate (CBH) and mixed alkalis, was developed to achieve economical succinic acid production by Corynebacterium glutamicum. The C. glutamicum strains were immobilized in porous polyurethane filler (PPF). CBH was used efficiently as a carbon source instead of more expensive glucose. Moreover, as a novel method for regulating pH, the easily decomposing NaHCO3 was replaced by mixed alkalis (NaOH and Mg(OH)2) for succinic acid production by C. glutamicum. Using CBH and mixed alkalis in the immobilized batch fermentation system, succinic acid productivity of 0.42gL(-1)h(-1) was obtained from 35gL(-1) glucose of CBH, which is similar to that obtained with conventional free-cell fermentation with glucose and NaHCO3. In repeated batch fermentation, an average of 22.5gL(-1) succinic acid could be obtained from each batch, which demonstrated the enhanced stability of the immobilized C. glutamicum cells. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fermentation performance of lactic acid bacteria in different lupin substrates-influence and degradation ability of antinutritives and secondary plant metabolites.

PubMed

Fritsch, C; Vogel, R F; Toelstede, S

2015-10-01

The main objectives were to determine the influence of secondary plant metabolites and antinutritives in lupin seeds on the fermentation performance of lactic acid bacteria and to study their ability to degrade these substances. The suitability of lupin raw materials as fermentation substrates was examined. To evaluate the fermentation performance, microbial growth, metabolite formation and substrate uptake in three different lupin substrates was monitored. On the one hand, a lupin protein isolate, which contained only trace amounts of phytochemicals was used in the study. On the other hand, the flour of Lupinus angustifolius cv. Boregine and the flour of the alkaloid rich lupin Lupinus angustifolius cv. Azuro were inoculated with Bifidobacterium animalis subsp. lactis, Pediococcus pentosaceus, Lactobacillus plantarum and Lactococcus lactis subsp. lactis. The micro-organisms showed no significant differences in the fermentation performance on the different lupin flours. Similarly, the growth of most strains on lupin protein isolate was comparable to that on the lupin flours. The fermentation with Bifidobacterium animalis subsp. lactis led to a significant decrease in flatulence causing oligosaccharides. During fermentation with Lactobacillus plantarum the phytic acid content was partially degraded. Neither the secondary plant metabolites nor the antinutritives of lupin flour inhibited the growth or metabolic activity of the tested micro-organisms. Therefore, lupin flour is suitable for lactic fermentation. Some strains showed the ability to degrade oligosaccharides or phytic acid. This work contributes to the fundamental knowledge of the metabolism of lactic acid bacteria during fermentation of lupin substrates. Fermentation of lupin raw materials could be used to improve the nutritional value of the substrates due to the reduction of antinutritives. © 2015 The Society for Applied Microbiology.

Kefir immobilized on corn grains as biocatalyst for lactic acid fermentation and sourdough bread making.

PubMed

Plessas, Stavros; Alexopoulos, Athanasios; Bekatorou, Argyro; Bezirtzoglou, Eugenia

2012-12-01

The natural mixed culture kefir was immobilized on boiled corn grains to produce an efficient biocatalyst for lactic acid fermentation with direct applications in food production, such as sourdough bread making. The immobilized biocatalyst was initially evaluated for its efficiency for lactic acid production by fermentation of cheese whey at various temperatures. The immobilized cells increased the fermentation rate and enhanced lactic acid production compared to free kefir cells. Maximum lactic acid yield (68.8 g/100 g) and lactic acid productivity (12.6 g/L per day) were obtained during fermentation by immobilized cells at 37 °C. The immobilized biocatalyst was then assessed as culture for sourdough bread making. The produced sourdough breads had satisfactory specific loaf volumes and good sensory characteristics. Specifically, bread made by addition of 60% w/w sourdough containing kefir immobilized on corn was more resistant regarding mould spoilage (appearance during the 11(th) day), probably due to higher lactic acid produced (2.86 g/Kg of bread) compared to the control samples. The sourdough breads made with the immobilized biocatalyst had aroma profiles similar to that of the control samples as shown by headspace SPME GC-MS analysis. © 2012 Institute of Food Technologists®

Superparamagnetic poly(methyl methacrylate) beads for nattokinase purification from fermentation broth.

PubMed

Yang, Chengli; Xing, Jianmin; Guan, Yueping; Liu, Huizhou

2006-09-01

An effective method for purification of nattokinase from fermentation broth using magnetic poly(methyl methacrylate) (PMMA) beads immobilized with p-aminobenzamidine was proposed in this study. Firstly, magnetic PMMA beads with a narrow size distribution were prepared by spraying suspension polymerization. Then, they were highly functionalized via transesterification reaction with polyethylene glycol. The surface hydroxyl-modified magnetic beads obtained were further modified with chloroethylamine to transfer the surface amino-modified magnetic functional beads. The morphology and surface functionality of the magnetic beads were examined by scanning electron microscopy and Fourier transform infrared. An affinity ligand, p-aminobenzamidine was covalently immobilized to the amino-modified magnetic beads by the glutaraldehyde method for nattokinase purification directly from the fermentation broth. The purification factor and the recovery of the enzyme activity were found to be 8.7 and 85%, respectively. The purification of nattokinase from fermentation broth by magnetic beads only took 40 min, which shows a very fast purification of nattokinase compared to traditional purification methods.

Conversion of Thin Stillage Compounds using Endemic Bacteria Augmented with Lactobacillus panis PM1B.

PubMed

Ratanapariyanuch, Kornsulee; Shim, Youn Young; Reaney, Martin J T

2016-10-04

A consortium of organisms endemic in wheat-based thin stillage (W-TS) obtained from a commercial ethanol production converts glycerol to 1,3-propanediol (1,3-PD) and lactic acid to acetic acid. We sought to improve conditions for 1,3-PD and acetic acid production to be used in future studies of industrial isolation of these compounds from two-stage fermentation. Occasionally stillage fermentation proceeded slowly but an inoculum of Lactobacillus panis PM1B augmented both fermentation rate and extent. Fermentation rate and product yield were enhanced by adjusting pH to 5 daily, adding glucose and glycerol (molar ratio 0.1:1), adding freeze-dried W-TS, and adding vitamins (B 2 , B 3 , and B 12 ). 1,3-PD and 3-HPA did not inhibit 1,3-PD production during fermentation. Moreover, agitation did not improve fermentation rate or extent. Corn sugar was a suitable substitute for glucose. Fermentation was performed at both 20 and 150 L, with 1,3-PD production of 2% (w/v, 20 g/L) being routinely achieved or exceeded.

Homo-D-lactic acid fermentation from arabinose by redirection of the phosphoketolase pathway to the pentose phosphate pathway in L-lactate dehydrogenase gene-deficient Lactobacillus plantarum.

PubMed

Okano, Kenji; Yoshida, Shogo; Tanaka, Tsutomu; Ogino, Chiaki; Fukuda, Hideki; Kondo, Akihiko

2009-08-01

Optically pure d-lactic acid fermentation from arabinose was achieved by using the Lactobacillus plantarum NCIMB 8826 strain whose l-lactate dehydrogenase gene was deficient and whose phosphoketolase gene was substituted with a heterologous transketolase gene. After 27 h of fermentation, 38.6 g/liter of d-lactic acid was produced from 50 g/liter of arabinose.

Positive selection on D-lactate dehydrogenases of Lactobacillus delbrueckii subspecies bulgaricus.

PubMed

Zhang, Jifeng; Gong, Guangyu; Wang, Xiao; Zhang, Hao; Tian, Weidong

2015-08-01

Lactobacillus delbrueckii has been widely used for yogurt fermentation. It has genes encoding both D- and L-type lactate dehydrogenases (LDHs) that catalyse the production of L(+) or D(-) stereoisomer of lactic acid. D-lactic acid is the primary lactate product by L. delbrueckii, yet it cannot be metabolised by human intestine. Since it has been domesticated for long time, an interesting question arises regarding to whether the selection pressure has affected the evolution of both L-LDH and D-LDH genes in the genome. To answer this question, in this study the authors first investigated the evolution of these two genes by constructing phylogenetic trees. They found that D-LDH-based phylogenetic tree could better represent the phylogenetic relationship in the acidophilus complex than L-LDH-based tree. They next investigated the evolutions of LDH genes of L. delbrueckii at amino acid level, and found that D-LDH gene in L. delbrueckii is positively selected, possibly a consequence of long-term domestication. They further identified four amino acids that are under positive selection. One of them, V261, is located at the centre of three catalytic active sites, indicating likely functional effects on the enzyme activity. The selection from the domestication process thus provides direction for future engineering of D-LDH.

Production of L-valine from metabolically engineered Corynebacterium glutamicum.

PubMed

Wang, Xiaoyuan; Zhang, Hailing; Quinn, Peter J

2018-05-01

L-Valine is one of the three branched-chain amino acids (valine, leucine, and isoleucine) essential for animal health and important in metabolism; therefore, it is widely added in the products of food, medicine, and feed. L-Valine is predominantly produced through microbial fermentation, and the production efficiency largely depends on the quality of microorganisms. In recent years, continuing efforts have been made in revealing the mechanisms and regulation of L-valine biosynthesis in Corynebacterium glutamicum, the most utilitarian bacterium for amino acid production. Metabolic engineering based on the metabolic biosynthesis and regulation of L-valine provides an effective alternative to the traditional breeding for strain development. Industrially competitive L-valine-producing C. glutamicum strains have been constructed by genetically defined metabolic engineering. This article reviews the global metabolic and regulatory networks responsible for L-valine biosynthesis, the molecular mechanisms of regulation, and the strategies employed in C. glutamicum strain engineering.

Plant-based Paste Fermented by Lactic Acid Bacteria and Yeast: Functional Analysis and Possibility of Application to Functional Foods

PubMed Central

Kuwaki, Shinsuke; Nakajima, Nobuyoshi; Tanaka, Hidehiko; Ishihara, Kohji

2012-01-01

A plant-based paste fermented by lactic acid bacteria and yeast (fermented paste) was made from various plant materials. The paste was made of fermented food by applying traditional food-preservation techniques, that is, fermentation and sugaring. The fermented paste contained major nutrients (carbohydrates, proteins, and lipids), 18 kinds of amino acids, and vitamins (vitamin A, B1, B2, B6, B12, E, K, niacin, biotin, pantothenic acid, and folic acid). It contained five kinds of organic acids, and a large amount of dietary fiber and plant phytochemicals. Sucrose from brown sugar, used as a material, was completely resolved into glucose and fructose. Some physiological functions of the fermented paste were examined in vitro. It was demonstrated that the paste possessed antioxidant, antihypertensive, antibacterial, anti-inflammatory, anti-allergy and anti-tyrosinase activities in vitro. It was thought that the fermented paste would be a helpful functional food with various nutrients to help prevent lifestyle diseases. PMID:25114554

Transcriptome analysis of Lactococcus lactis subsp. lactis during milk acidification as affected by dissolved oxygen and the redox potential.

PubMed

Larsen, Nadja; Moslehi-Jenabian, Saloomeh; Werner, Birgit Brøsted; Jensen, Maiken Lund; Garrigues, Christel; Vogensen, Finn Kvist; Jespersen, Lene

2016-06-02

Performance of Lactococcus lactis as a starter culture in dairy fermentations depends on the levels of dissolved oxygen and the redox state of milk. In this study the microarray analysis was used to investigate the global gene expression of L. lactis subsp. lactis DSM20481(T) during milk acidification as affected by oxygen depletion and the decrease of redox potential. Fermentations were carried out at different initial levels of dissolved oxygen (dO2) obtained by milk sparging with oxygen (high dO2, 63%) or nitrogen (low dO2, 6%). Bacterial exposure to high initial oxygen resulted in overexpression of genes involved in detoxification of reactive oxygen species (ROS), oxidation-reduction processes, biosynthesis of trehalose and down-regulation of genes involved in purine nucleotide biosynthesis, indicating that several factors, among them trehalose and GTP, were implicated in bacterial adaptation to oxidative stress. Generally, transcriptional changes were more pronounced during fermentation of oxygen sparged milk. Genes up-regulated in response to oxygen depletion were implicated in biosynthesis and transport of pyrimidine nucleotides, branched chain amino acids and in arginine catabolic pathways; whereas genes involved in salvage of nucleotides and cysteine pathways were repressed. Expression pattern of genes involved in pyruvate metabolism indicated shifts towards mixed acid fermentation after oxygen depletion with production of specific end-products, depending on milk treatment. Differential expression of genes, involved in amino acid and pyruvate pathways, suggested that initial oxygen might influence the release of flavor compounds and, thereby, flavor development in dairy fermentations. The knowledge of molecular responses involved in adaptation of L. lactis to the shifts of redox state and pH during milk fermentations is important for the dairy industry to ensure better control of cheese production. Copyright © 2016 Elsevier B.V. All rights reserved.

High-efficiency removal of phytic acid in soy meal using two-stage temperature-induced Aspergillus oryzae solid-state fermentation.

PubMed

Chen, Liyan; Vadlani, Praveen V; Madl, Ronald L

2014-01-15

Phytic acid of soy meal (SM) could influence protein and important mineral digestion of monogastric animals. Aspergillus oryzae (ATCC 9362) solid-state fermentation was applied to degrade phytic acid in SM. Two-stage temperature fermentation protocol was investigated to increase the degradation rate. The first stage was to maximize phytase production and the second stage was to realize the maximum enzymatic degradation. In the first stage, a combination of 41% moisture, a temperature of 37 °C and inoculum size of 1.7 mL in 5 g substrate (dry matter basis) favored maximum phytase production, yielding phytase activity of 58.7 U, optimized via central composite design. By the end of second-stage fermentation, 57% phytic acid was degraded from SM fermented at 50 °C, compared with 39% of that fermented at 37 °C. The nutritional profile of fermented SM was also studied. Oligosaccharides were totally removed after fermentation and 67% of total non-reducing polysaccharides were decreased. Protein content increased by 9.5%. Two-stage temperature protocol achieved better phytic acid degradation during A. oryzae solid state fermentation. The fermented SM has lower antinutritional factors (phytic acid, oligosaccharides and non-reducing polysaccharides) and higher nutritional value for animal feed. © 2013 Society of Chemical Industry.

Biosuccinic Acid from Lignocellulosic-Based Hexoses and Pentoses by Actinobacillus succinogenes: Characterization of the Conversion Process.

PubMed

Ferone, Mariateresa; Raganati, Francesca; Olivieri, Giuseppe; Salatino, Piero; Marzocchella, Antonio

2017-12-01

Succinic acid (SA) is a well-established chemical building block. Actinobacillus succinogenes fermentation is by far the most investigated route due to very promising high SA yield and titer on several sugars. This study contributes to include the SA production within the concept of biorefinery of lignocellulose biomass. The study was focused on the SA production by A. succinogenes DSM 22257 using sugars representative from lignocellulose hydrolysis-glucose, mannose, arabinose, and xylose-as carbon source. Single sugar batch fermentation tests and mixture sugar fermentation tests were carried out. All the sugars investigated were converted in succinic acid by A. succinogenes. The best fermentation performances were measured in tests with glucose as carbon source. The bacterial growth kinetics was characterized by glucose inhibition. No inhibition phenomena were observed with the other sugar investigated. The sugar mixture fermentation tests highlighted the synergic effects of the co-presence of the four sugars. Under the operating conditions tested, the final concentration of succinic acid in the sugar mixture test was larger (27 g/L) than that expected (25.5 g/L) by combining the fermentation of the single sugar. Moreover, the concentration of acetic and formic acid was lower, consequently obtaining an increment in the succinic acid specificity.

Comparison of high-titer lactic acid fermentation from NaOH- and NH3-H2O2-pretreated corncob by Bacillus coagulans using simultaneous saccharification and fermentation.

PubMed

Zhang, Zhenting; Xie, Yuejiao; He, Xiaolan; Li, Xinli; Hu, Jinlong; Ruan, Zhiyong; Zhao, Shumiao; Peng, Nan; Liang, Yunxiang

2016-11-17

Lignocellulose is one of the most abundant renewable feedstocks that has attracted considerable attention as a substrate for biofuel and biochemical production. One such biochemical product, lactic acid, is an important fermentation product because of its great potential for the production of biodegradable and biocompatible polylactic acid. High-titer lactic acid production from lignocellulosic materials has been achieved recently; however, it requires biodetoxification or results in large amounts of waste washing water. In this study, we employed two alkaline pretreatment methods and compared their effects on lactic acid fermentation of pretreated corncob by Bacillus coagulans LA204 using fed-batch simultaneous saccharification and fermentation under non-sterile conditions. The lactic acid titer, yield, and productivity from 16% (w/w) NaOH-pretreated and washed corncob were 122.99 g/L, 0.77 g/g corncob, and 1.37 g/L/h, respectively, and from 16% NH 3 -H 2 O 2 -pretreated and washed corncob were 118.60 g/L, 0.74 g/g corncob, and 1.32 g/L/h, respectively. Importantly, the lactic acid titer, yield, and productivity from 18.4% NH 3 -H 2 O 2 -pretreated and unwashed corncob by using fed-batch simultaneous saccharification and fermentation reached 79.47 g/L, 0.43 g/g corncob, and 1.10 g/L/h, respectively, demonstrating that this method is possible for industrial applications and saves washing water.

A novel membrane-integrated fermentation reactor system: application to pyruvic acid production in continuous culture by Torulopsis glabrata.

PubMed

Sawai, Hideki; Mimitsuka, Takashi; Minegishi, Shin-Ichi; Henmi, Masahiro; Yamada, Katsushige; Shimizu, Sakayu; Yonehara, Tetsu

2011-08-01

This paper describes the performance of a novel bio-reactor system, the membrane-integrated fermentation reactor (MFR), for efficient continuous fermentation. The MFR, equipped with an autoclavable polyvinylidene difluoride membrane, has normally been used for biological wastewater treatment. The productivity of the MFR system, applied to the continuous production of pyruvic acid by the yeast Torulopsis glabrata, was remarkably high. The volumetric productivity of pyruvic acid increased up to 4.2 g/l/h, about four times higher than that of batch fermentation. Moreover, the membrane was able to filter fermentation broth for more than 300 h without fouling even though the cell density of the fermentation broth reached 600 as OD(660). Transmembrane pressure, used as an indicator of membrane fouling, remained below 5 kPa throughout the continuous fermentation. These results clearly indicate that the MFR system is a simple and highly efficient system that is applicable to the fermentative production of a range of biochemicals.

Lactic acid bacteria involved in cocoa beans fermentation from Ivory Coast: Species diversity and citrate lyase production.

PubMed

Ouattara, Hadja D; Ouattara, Honoré G; Droux, Michel; Reverchon, Sylvie; Nasser, William; Niamke, Sébastien L

2017-09-01

Microbial fermentation is an indispensable process for high quality chocolate from cocoa bean raw material. lactic acid bacteria (LAB) are among the major microorganisms responsible for cocoa fermentation but their exact role remains to be elucidated. In this study, we analyzed the diversity of LAB in six cocoa producing regions of Ivory Coast. Ribosomal 16S gene sequence analysis showed that Lactobacillus plantarum and Leuconostoc mesenteroides are the dominant LAB species in these six regions. In addition, other species were identified as the minor microbial population, namely Lactobacillus curieae, Enterococcus faecium, Fructobacillus pseudoficulneus, Lactobacillus casei, Weissella paramesenteroides and Weissella cibaria. However, in each region, the LAB microbial population was composed of a restricted number of species (maximum 5 species), which varied between the different regions. LAB implication in the breakdown of citric acid was investigated as a fundamental property for a successful cocoa fermentation process. High citrate lyase producer strains were characterized by rapid citric acid consumption, as revealed by a 4-fold decrease in citric acid concentration in the growth medium within 12h, concomitant with an increase in acetic acid and lactic acid concentration. The production of citrate lyase was strongly dependent on environmental conditions, with optimum production at acidic pH (pH<5), and moderate temperature (30-40°C), which corresponds to conditions prevailing in the early stage of natural cocoa fermentation. This study reveals that one of the major roles of LAB in the cocoa fermentation process involves the breakdown of citric acid during the early stage of cocoa fermentation through the activity of citrate lyase. Copyright © 2017 Elsevier B.V. All rights reserved.

Role of a membrane-bound aldehyde dehydrogenase complex AldFGH in acetic acid fermentation with Acetobacter pasteurianus SKU1108.

PubMed

Yakushi, Toshiharu; Fukunari, Seiya; Kodama, Tomohiro; Matsutani, Minenosuke; Nina, Shun; Kataoka, Naoya; Theeragool, Gunjana; Matsushita, Kazunobu

2018-05-01

Acetic acid fermentation is widely considered a consequence of ethanol oxidation by two membrane-bound enzymes-alcohol dehydrogenase and aldehyde dehydrogenase (ALDH)-of acetic acid bacteria. Here, we used a markerless gene disruption method to construct a mutant of the Acetobacter pasteurianus strain SKU1108 with a deletion in the aldH gene, which encodes the large catalytic subunit of a heterotrimeric ALDH complex (AldFGH), to examine the role of AldFGH in acetic acid fermentation. The ΔaldH strain grew less on ethanol-containing medium, i.e., acetic acid fermentation conditions, than the wild-type strain and significantly accumulated acetaldehyde in the culture medium. Unexpectedly, acetaldehyde oxidase activity levels of the intact ΔaldH cells and the ΔaldH cell membranes were similar to those of the wild-type strain, which might be attributed to an additional ALDH isozyme (AldSLC). The apparent K M values of the wild-type and ΔaldH membranes for acetaldehyde were similar to each other, when the cells were cultured in nonfermentation conditions, where ΔaldH cells grow as well as the wild-type cells. However, the membranes of the wild-type cells grown under fermentation conditions showed a 10-fold lower apparent K M value than those of the cells grown under nonfermentation conditions. Under fermentation conditions, transcriptional levels of a gene for AldSLC were 10-fold lower than those under nonfermentation conditions, whereas aldH transcript levels were not dramatically changed under the two conditions. We suggest that A. pasteurianus SKU1108 has two ALDHs, and the AldFGH complex is indispensable for acetic acid fermentation and is the major enzyme under fermentation conditions.

Effect of acetic acid in recycling water on ethanol production for cassava in an integrated ethanol-methane fermentation process.

PubMed

Yang, Xinchao; Wang, Ke; Zhang, Jianhua; Tang, Lei; Mao, Zhonggui

2016-11-01

Recently, the integrated ethanol-methane fermentation process has been studied to prevent wastewater pollution. However, when the anaerobic digestion reaction runs poorly, acetic acid will accumulate in the recycling water. In this paper, we studied the effect of low concentration of acetic acid (≤25 mM) on ethanol fermentation at different initial pH values (4.2, 5.2 or 6.2). At an initial pH of 4.2, ethanol yields increased by 3.0% and glycerol yields decreased by 33.6% as the acetic acid concentration was increased from 0 to 25 mM. Raising the concentration of acetic acid to 25 mM increased the buffering capacity of the medium without obvious effects on biomass production in the cassava medium. Acetic acid was metabolized by Saccharomyces cerevisiae for the reason that the final concentration of acetic acid was 38.17% lower than initial concentration at pH 5.2 when 25 mM acetic acid was added. These results confirmed that a low concentration of acetic acid in the process stimulated ethanol fermentation. Thus, reducing the acetic acid concentration to a controlled low level is more advantageous than completely removing it.

Transformation of chemical constituents of lychee wine by simultaneous alcoholic and malolactic fermentations.

PubMed

Chen, Dai; Liu, Shao-Quan

2016-04-01

This work examined for the first time the impact of malolactic fermentation (MLF) on the chemical constituents of lychee wine. Oenococcus oeni Viniflora Oenos (MLF inducer) and Saccharomyces cerevisiae MERIT.ferm were co-inoculated into lychee juice to induce simultaneous alcoholic fermentation (AF) and MLF. MLF did not affect sugar utilisation and ethanol production statistically (8.54% v/v for MLF and 9.27% v/v for AF). However, MLF resulted in dramatic degradation of malic and citric acids with concomitant increases of lactic acid, ethyl lactate and pH. The final concentrations of acetic and succinic acids between AF and MLF wines had no significant difference. The MLF wine contained significantly higher amounts of amino acids than the AF wine. More importantly, MLF significantly elevated the levels of potent aroma-active compounds including isoamyl acetate, linalool, geraniol and cis-rose oxide (to levels above or near respective detection thresholds), suggesting that MLF is an effective way of retaining the original lychee flavour. Copyright © 2015 Elsevier Ltd. All rights reserved.

High-level coproduction, purification and characterisation of laccase and exopolysaccharides by Coriolus versicolor.

PubMed

Que, Youxiong; Sun, Shujing; Xu, Liping; Zhang, Yuye; Zhu, Hu

2014-09-15

In this study, a two-stage pH-shift fermentation process was developed for the coproduction of laccase and exopolysaccharides (EPS) by Coriolus versicolor. At the same time, laccase and EPS were purified and characterised in detail. The results showed that the highest laccase and EPS production reached 7680 U l(-1) and 8.2 g l(-1). Furthermore, the flow behaviour of fermentation broth was Newtonian and the maximum μ(ap) was 2.7×10(-3) Pa s. The MW of laccase was 64 kDa and it showed a pI value of 4.2. The CD analysis showed that laccase had a high α-helical content (68%). The MW of the purified EPS was determined to be 1.8×10(6) Da, consisting of carbohydrates (87.6%) and proteins (12.4%). The EPS consisted of 17 amino acids, mainly serine (11.3%), glutamic acid (12.60%), leucine (13.3%) and phenylalanine (9.4%) in protein moiety, and three monosaccharides (galactose, mannose and xylose). Copyright © 2014 Elsevier Ltd. All rights reserved.

Production of cured meat color in nitrite-free Harbin red sausage by Lactobacillus fermentum fermentation.

PubMed

Zhang, Xue; Kong, Baohua; Xiong, Youling L

2007-12-01

Lactobacillus fermentum was substituted for nitrite to produce cured pink color in a Chinese-style sausage. Treatments included inoculations (10(4), 10(6), and 10(8)CFU/g meat) followed by fermentation at 30°C for 8h and then at 4°C for 16h. Control sausage (with sodium nitrite, 60mg/kg meat) was cured at 4°C for 24h without L. fermentum. The UV-Vis spectra of pigment extract from L. fermentum-treated sausage were identical to that of nitrosylmyoglobin (NO-Mb) formed in nitrite-treated control. The NO-Mb concentration and the colorimetric a(∗) value of sausage treated with 10(8)CFU/g meat of L. fermentum essentially replicated those in nitrite-cured meat. Free amino acid content in sausage treated with L. fermentum was greater and the pH slightly lower compared with the nitrite-cured control sample. This study showed that L. fermentum has the potential to substitute for nitrite in the sausage production.

Monitoring the impact of an aspartic protease (MpAPr1) on grape proteins and wine properties.

PubMed

Theron, Louwrens Wiid; Bely, Marina; Divol, Benoit

2018-04-23

The perception of haze in wine is brought about when pathogenesis-related proteins become unstable and aggregate, subsequently resulting in crosslinking until it develops into light-dispersing particles. Elimination of these proteins is usually achieved via bentonite fining, which, although effective, suffers from several drawbacks. The utilization of proteases has been proposed as an ideal alternative. In a previous study, an aspartic protease (MpAPr1) from the yeast Metschnikowia pulcherrima was purified and shown to be partially active against grape proteins in synthetic medium. In this study, the effects of pure MpAPr1 supplemented to Sauvignon Blanc juice on subsequent fermentation were investigated. The juice was incubated for 48 h and thereafter inoculated with Saccharomyces cerevisiae. Results revealed that the enzyme had no observable effects on fermentation performance and retained activity throughout. Protein degradation could be detected and resulted in a significant modification of the wine composition and an increase in the presence of certain volatile compounds, especially those linked to amino acid metabolism.

Identification of Lactobacillus sakei genes induced during meat fermentation and their role in survival and growth.

PubMed

Hüfner, Eric; Markieton, Tobias; Chaillou, Stéphane; Crutz-Le Coq, Anne-Marie; Zagorec, Monique; Hertel, Christian

2007-04-01

Lactobacillus sakei is a lactic acid bacterium that is ubiquitous in the food environment and is one of the most important constituents of commercial meat starter cultures. In this study, in vivo expression technology (IVET) was applied to investigate gene expression of L. sakei 23K during meat fermentation. The IVET vector used (pEH100) contained promoterless and transcriptionally fused reporter genes mediating beta-glucuronidase activity and erythromycin resistance. A genomic library of L. sakei 23K was established, and the clones were subjected to fermentation in a raw-sausage model. Fifteen in carne-induced fusions were identified. Several genes encoded proteins which are likely to contribute to stress-related functions. One of these genes was involved in acquisition of ammonia from amino acids, and the remaining either were part of functionally unrelated pathways or encoded hypothetical proteins. The construction and use of isogenic mutants in the sausage model suggested that four genes have an impact on the performance of L. sakei during raw-sausage fermentation. Inactivation of the heat shock regulator gene ctsR resulted in increased growth, whereas knockout of the genes asnA2, LSA1065, and LSA1194 resulted in attenuated performance compared to the wild-type strain. The results of our study are the first to provide an insight into the transcriptional response of L. sakei when growing in the meat environment. In addition, this study establishes a molecular basis which allows investigation of bacterial properties that are likely to contribute to the ecological performance of the organism and to influence the final outcome of sausage fermentation.

Microbial process for the preparation of acetic acid as well as solvent for its extraction from the fermentation broth

DOEpatents

Gaddy, James L.; Clausen, Edgar C.; Ko, Ching-Whan; Wade, Leslie E.; Wikstrom, Carl V.

2002-01-01

A modified water-immiscible solvent useful in the extraction of acetic acid from aqueous streams is a substantially pure mixture of isomers of highly branched di-alkyl amines. This solvent is substantially devoid of mono-alkyl amines and alcohols. Solvent mixtures formed of such a modified solvent with a desired cosolvent, preferably a low boiling hydrocarbon which forms an azeotrope with water are useful in the extraction of acetic acid from aqueous gaseous streams. An anaerobic microbial fermentation process for the production of acetic acid employs such solvents, under conditions which limit amide formation by the solvent and thus increase the efficiency of acetic acid recovery. Methods for the direct extraction of acetic acid and the extractive fermentation of acetic acid also employ the modified solvents and increase efficiency of acetic acid production. Such increases in efficiency are also obtained where the energy source for the microbial fermentation contains carbon dioxide and the method includes a carbon dioxide stripping step prior to extraction of acetic acid in solvent.

Comprehensive assessment of the L-lysine production process from fermentation of sugarcane molasses.

PubMed

Anaya-Reza, Omar; Lopez-Arenas, Teresa

2017-07-01

L-Lysine is an essential amino acid that can be produced by chemical processes from fossil raw materials, as well as by microbial fermentation, the latter being a more efficient and environmentally friendly procedure. In this work, the production process of L-lysine-HCl is studied using a systematic approach based on modeling and simulation, which supports decision making in the early stage of process design. The study considers two analysis stages: first, the dynamic analysis of the fermentation reactor, where the conversion of sugars from sugarcane molasses to L-lysine with a strain of Corynebacterium glutamicum is carried out. In this stage, the operation mode (either batch or fed batch) and operating conditions of the fermentation reactor are defined to reach the maximum technical criteria. Afterwards, the second analysis stage relates to the industrial production process of L-lysine-HCl, where the fermentation reactor, upstream processing, and downstream processing are included. In this stage, the influence of key parameters on the overall process performance is scrutinized through the evaluation of several technical, economic, and environmental criteria, to determine a profitable and sustainable design of the L-lysine production process. The main results show how the operating conditions, process design, and selection of evaluation criteria can influence in the conceptual design. The best plant design shows maximum product yield (0.31 g L-lysine/g glucose) and productivity (1.99 g/L/h), achieving 26.5% return on investment (ROI) with a payback period (PBP) of 3.8 years, decreasing water and energy consumption, and with a low potential environmental impact (PEI) index.

Fermentation assays reveal differences in sugar and (off-) flavor metabolism across different Brettanomyces bruxellensis strains.

PubMed

Crauwels, Sam; Van Opstaele, Filip; Jaskula-Goiris, Barbara; Steensels, Jan; Verreth, Christel; Bosmans, Lien; Paulussen, Caroline; Herrera-Malaver, Beatriz; de Jonge, Ronnie; De Clippeleer, Jessika; Marchal, Kathleen; De Samblanx, Gorik; Willems, Kris A; Verstrepen, Kevin J; Aerts, Guido; Lievens, Bart

2017-01-01

Brettanomyces (Dekkera) bruxellensis is an ascomycetous yeast of major importance in the food, beverage and biofuel industry. It has been isolated from various man-made ecological niches that are typically characterized by harsh environmental conditions such as wine, beer, soft drink, etc. Recent comparative genomics studies revealed an immense intraspecific diversity, but it is still unclear whether this genetic diversity also leads to systematic differences in fermentation performance and (off-)flavor production, and to what extent strains have evolved to match their ecological niche. Here, we present an evaluation of the fermentation properties of eight genetically diverse B. bruxellensis strains originating from beer, wine and soft drinks. We show that sugar consumption and aroma production during fermentation are determined by both the yeast strain and composition of the medium. Furthermore, our results indicate a strong niche adaptation of B. bruxellensis, most clearly for wine strains. For example, only strains originally isolated from wine were able to thrive well and produce the typical Brettanomyces-related phenolic off-flavors 4-ethylguaiacol and 4-ethylphenol when inoculated in red wine. Sulfite tolerance was found as a key factor explaining the observed differences in fermentation performance and off-flavor production. Sequence analysis of genes related to phenolic off-flavor production, however, revealed only marginal differences between the isolates tested, especially at the amino acid level. Altogether, our study provides novel insights in the Brettanomyces metabolism of flavor production, and is highly relevant for both the wine and beer industry. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Genome-wide identification of genes involved in growth and fermentation activity at low temperature in Saccharomyces cerevisiae.

PubMed

Salvadó, Zoel; Ramos-Alonso, Lucía; Tronchoni, Jordi; Penacho, Vanessa; García-Ríos, Estéfani; Morales, Pilar; Gonzalez, Ramon; Guillamón, José Manuel

2016-11-07

Fermentation at low temperatures is one of the most popular current winemaking practices because of its reported positive impact on the aromatic profile of wines. However, low temperature is an additional hurdle to develop Saccharomyces cerevisiae wine yeasts, which are already stressed by high osmotic pressure, low pH and poor availability of nitrogen sources in grape must. Understanding the mechanisms of adaptation of S. cerevisiae to fermentation at low temperature would help to design strategies for process management, and to select and improve wine yeast strains specifically adapted to this winemaking practice. The problem has been addressed by several approaches in recent years, including transcriptomic and other high-throughput strategies. In this work we used a genome-wide screening of S. cerevisiae diploid mutant strain collections to identify genes that potentially contribute to adaptation to low temperature fermentation conditions. Candidate genes, impaired for growth at low temperatures (12°C and 18°C), but not at a permissive temperature (28°C), were deleted in an industrial homozygous genetic background, wine yeast strain FX10, in both heterozygosis and homozygosis. Some candidate genes were required for growth at low temperatures only in the laboratory yeast genetic background, but not in FX10 (namely the genes involved in aromatic amino acid biosynthesis). Other genes related to ribosome biosynthesis (SNU66 and PAP2) were required for low-temperature fermentation of synthetic must (SM) in the industrial genetic background. This result coincides with our previous findings about translation efficiency with the fitness of different wine yeast strains at low temperature. Copyright © 2016 Elsevier B.V. All rights reserved.

Microbial process for the preparation of acetic acid as well as solvent for its extraction from the fermentation broth

DOEpatents

Gaddy, James L.; Clausen, Edgar C.; Ko, Ching-Whan; Wade, Leslie E.; Wikstrom, Carl V.

2006-07-11

A modified water-immiscible solvent useful in the extraction of acetic acid from aqueous streams is a substantially pure mixture of isomers of highly branched di-alkyl amines. This solvent is substantially devoid of mono-alkyl amines and alcohols. Solvent mixtures formed of such a modified solvent with a desired cosolvent, preferably a low boiling hydrocarbon which forms an azeotrope with water are useful in the extraction of acetic acid from aqueous gaseous streams. An anaerobic microbial fermentation process for the production of acetic acid employs such solvents, under conditions which limit amide formation by the solvent and thus increase the efficiency of acetic acid recovery. Methods for the direct extraction of acetic acid and the extractive fermentation of acetic acid also employ the modified solvents and increase efficiency of acetic acid production. Such increases in efficiency are also obtained where the energy source for the microbial fermentation contains carbon dioxide and the method includes a carbon dioxide stripping step prior to extraction of acetic acid in solvent.

New fermentation processes for producing itaconic acid and citric acid for industrial uses

USDA-ARS?s Scientific Manuscript database

Itaconic acid is an important industrial chemical that we have produced by fermentation of simple sugars using the yeast Pseudozyma antarctica. Itaconic acid is priced at ~$4 per kg and has an annual market volume of about 15,000 metric tons. Itaconic acid is used in the polymer industry and for m...

The influence of narrow-leafed lupin seed fermentation on their chemical composition and ileal digestibility and microbiota in growing pigs.

PubMed

Zaworska, Anita; Frankiewicz, Andrzej; Kasprowicz-Potocka, Małgorzata

2017-08-01

The aims of this study were to provide a controlled fermentation process of blue lupin seeds (Lupinus angustifolius, cv. Neptun), monitor the changes in seed composition and determine the influence of the fermentation on the apparent ileal digestibility (AID) of crude protein (CP) and amino acids in growing pigs, compared with raw lupin seeds. The fermentation with bacteria and yeast was conducted for 24 h at 25ºC under aerobic conditions. Seed fermentation increased the contents of CP, fibre, fat and ash and most of the analysed amino acids but reduced the levels of the nitrogen-free extractives. Furthermore, fermentation decreased the contents of raffinose family oligosaccharides and phytic acids but increased the alkaloid content. The AID was estimated on three barrows (mean initial body weight 25 kg), surgically fitted with a T-cannula in the distal ileum. The pigs received three diets, each for 6 d, within three experimental periods (3 × 3 Latin Square design). The diets contained soybean meal (Group SBM), raw lupin seeds (Group RL) or fermented lupin seeds (Group FL) as solely protein sources. Fermentation had a positive impact on the AID of CP and methionine, cysteine, isoleucine, leucine, phenylalanine and valine (p < 0.05). Feeding raw or fermented lupin seeds did not affect the microbial status of the ileal digesta. Moreover, ammonia content in the caecal digesta did not differ between Groups RL and FL, although it was significantly higher than in Group SBM. It can be concluded that the fermentation process modified the chemical composition of nutrients in seeds, which can influence the digestibility and utilisation of the fermentation product in animal diets compared to raw seeds.

Improvement of l-lactic acid productivity from sweet sorghum juice by repeated batch fermentation coupled with membrane separation.

PubMed

Wang, Yong; Meng, Hongyu; Cai, Di; Wang, Bin; Qin, Peiyong; Wang, Zheng; Tan, Tianwei

2016-07-01

In order to efficiently produce l-lactic acid from non-food feedstocks, sweet sorghum juice (SSJ), which is rich of fermentable sugars, was directly used for l-lactic acid fermentation by Lactobacillus rhamnosus LA-04-1. A membrane integrated repeated batch fermentation (MIRB) was developed for productivity improvement. High-cell-density fermentation was achieved with a final cell density (OD620) of 42.3, and the CCR effect was overcomed. When SSJ (6.77gL(-1) glucose, 4.51gL(-1) fructose and 50.46gL(-1) sucrose) was used as carbon source in MIRB process, l-lactic acid productivity was increased significantly from 1.45gL(-1)h(-1) (batch 1) to 17.55gL(-1)h(-1) (batch 6). This process introduces an effective way to produce l-lactic acid from SSJ. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Process development for continuous ethanol fermentation by the flocculating yeast under stillage backset conditions].

PubMed

Zi, Lihan; Liu, Chenguang; Bai, Fengwu

2014-02-01

Propionic acid, a major inhibitor to yeast cells, was accumulated during continuous ethanol fermentation from corn meal hydrolysate by the flocculating yeast under stillage backset conditions. Based on its inhibition mechanism in yeast cells, strategies were developed for alleviating this effect. Firstly, high temperature processes such as medium sterilization generated more propionic acid, which should be avoided. Propionic acid was reduced significantly during ethanol fermentation without medium sterilization, and concentrations of biomass and ethanol increased by 59.3% and 7.4%, respectively. Secondly, the running time of stillage backset should be controlled so that propionic acid accumulated would be lower than its half inhibition concentration IC50 (40 mmol/L). Finally, because low pH augmented propionic acid inhibition in yeast cells, a higher pH of 5.5 was validated to be suitable for ethanol fermentation under the stillage backset condition.

21 CFR 184.1033 - Citric acid.

Code of Federal Regulations, 2010 CFR

2010-04-01

... lemon or pineapple juice; by mycological fermentation using Candida spp., described in §§ 173.160 and... for the recovery of citric acid from Aspergillus niger fermentation liquor. (b) The ingredient meets...

Production of human insulin in an E. coli system with Met-Lys-human proinsulin as the expressed precursor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin-Qiu Chen; Hong-Tao Zhang; Mei-Hao Hu

1995-10-01

The construction of a gene encoding Lys-human proinsulin, its direct expression in E.coli, and the simple purification procedure are described here. The temperature inducible promotor was employed for induction in a very short time. The expression level could reach 20-30%. After a simple downstream processing and only one step of Sephadex G50 purification, 150 mg recombinant Lys-human proinsulin with a purity of up to 90% could be obtained easily from 1 L of high density fermentation medium. The obtained product is in the form of Met-Lys-human proinsulin because of the failure of the bacterial host to remove the initiator methioninemore » residue. The Lys-human proinsulin could be changed into human insulin by tryspin and carboxypeptidase B treatment in later steps. After separation with DEAE Sephadex A25, human insulin with expected amino acid composition and full native biological activity could be obtained with a yield of 50 mg/L fermentation medium. 20 refs., 5 figs., 4 tabs.« less

The effect of lactic acid bacteria on cocoa bean fermentation.

PubMed

Ho, Van Thi Thuy; Zhao, Jian; Fleet, Graham

2015-07-16

Cocoa beans (Theobroma cacao L.) are the raw material for chocolate production. Fermentation of cocoa pulp by microorganisms is crucial for developing chocolate flavor precursors. Yeasts conduct an alcoholic fermentation within the bean pulp that is essential for the production of good quality beans, giving typical chocolate characters. However, the roles of bacteria such as lactic acid bacteria and acetic acid bacteria in contributing to the quality of cocoa bean and chocolate are not fully understood. Using controlled laboratory fermentations, this study investigated the contribution of lactic acid bacteria to cocoa bean fermentation. Cocoa beans were fermented under conditions where the growth of lactic acid bacteria was restricted by the use of nisin and lysozyme. The resultant microbial ecology, chemistry and chocolate quality of beans from these fermentations were compared with those of indigenous (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii, Kluyveromyces marxianus and Saccharomyces cerevisiae, the lactic acid bacteria Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in control fermentations. In fermentations with the presence of nisin and lysozyme, the same species of yeasts and acetic acid bacteria grew but the growth of lactic acid bacteria was prevented or restricted. These beans underwent characteristic alcoholic fermentation where the utilization of sugars and the production of ethanol, organic acids and volatile compounds in the bean pulp and nibs were similar for beans fermented in the presence of lactic acid bacteria. Lactic acid was produced during both fermentations but more so when lactic acid bacteria grew. Beans fermented in the presence or absence of lactic acid bacteria were fully fermented, had similar shell weights and gave acceptable chocolates with no differences in sensory rankings. It was concluded that lactic acid bacteria may not be necessary for successful cocoa fermentation. Copyright © 2015. Published by Elsevier B.V.

Ethanol production from residual wood chips of cellulose industry: acid pretreatment investigation, hemicellulosic hydrolysate fermentation, and remaining solid fraction fermentation by SSF process.

PubMed

Silva, Neumara Luci Conceição; Betancur, Gabriel Jaime Vargas; Vasquez, Mariana Peñuela; Gomes, Edelvio de Barros; Pereira, Nei

2011-04-01

Current research indicates the ethanol fuel production from lignocellulosic materials, such as residual wood chips from the cellulose industry, as new emerging technology. This work aimed at evaluating the ethanol production from hemicellulose of eucalyptus chips by diluted acid pretreatment and the subsequent fermentation of the generated hydrolysate by a flocculating strain of Pichia stipitis. The remaining solid fraction generated after pretreatment was subjected to enzymatic hydrolysis, which was carried out simultaneously with glucose fermentation [saccharification and fermentation (SSF) process] using a strain of Saccharomyces cerevisiae. The acid pretreatment was evaluated using a central composite design for sulfuric acid concentration (1.0-4.0 v/v) and solid to liquid ratio (1:2-1:4, grams to milliliter) as independent variables. A maximum xylose concentration of 50 g/L was obtained in the hemicellulosic hydrolysate. The fermentation of hemicellulosic hydrolysate and the SSF process were performed in bioreactors and the final ethanol concentrations of 15.3 g/L and 28.7 g/L were obtained, respectively.

Dynamics and Biodiversity of Populations of Lactic Acid Bacteria and Acetic Acid Bacteria Involved in Spontaneous Heap Fermentation of Cocoa Beans in Ghana▿

PubMed Central

Camu, Nicholas; De Winter, Tom; Verbrugghe, Kristof; Cleenwerck, Ilse; Vandamme, Peter; Takrama, Jemmy S.; Vancanneyt, Marc; De Vuyst, Luc

2007-01-01

The Ghanaian cocoa bean heap fermentation process was studied through a multiphasic approach, encompassing both microbiological and metabolite target analyses. A culture-dependent (plating and incubation, followed by repetitive-sequence-based PCR analyses of picked-up colonies) and culture-independent (denaturing gradient gel electrophoresis [DGGE] of 16S rRNA gene amplicons, PCR-DGGE) approach revealed a limited biodiversity and targeted population dynamics of both lactic acid bacteria (LAB) and acetic acid bacteria (AAB) during fermentation. Four main clusters were identified among the LAB isolated: Lactobacillus plantarum, Lactobacillus fermentum, Leuconostoc pseudomesenteroides, and Enterococcus casseliflavus. Other taxa encompassed, for instance, Weissella. Only four clusters were found among the AAB identified: Acetobacter pasteurianus, Acetobacter syzygii-like bacteria, and two small clusters of Acetobacter tropicalis-like bacteria. Particular strains of L. plantarum, L. fermentum, and A. pasteurianus, originating from the environment, were well adapted to the environmental conditions prevailing during Ghanaian cocoa bean heap fermentation and apparently played a significant role in the cocoa bean fermentation process. Yeasts produced ethanol from sugars, and LAB produced lactic acid, acetic acid, ethanol, and mannitol from sugars and/or citrate. Whereas L. plantarum strains were abundant in the beginning of the fermentation, L. fermentum strains converted fructose into mannitol upon prolonged fermentation. A. pasteurianus grew on ethanol, mannitol, and lactate and converted ethanol into acetic acid. A newly proposed Weissella sp., referred to as “Weissella ghanaensis,” was detected through PCR-DGGE analysis in some of the fermentations and was only occasionally picked up through culture-based isolation. Two new species of Acetobacter were found as well, namely, the species tentatively named “Acetobacter senegalensis” (A. tropicalis-like) and “Acetobacter ghanaensis” (A. syzygii-like). PMID:17277227

Semi-industrial scale (30 m3) fed-batch fermentation for the production of D-lactate by Escherichia coli strain HBUT-D15.

PubMed

Fu, Xiangmin; Wang, Yongze; Wang, Jinhua; Garza, Erin; Manow, Ryan; Zhou, Shengde

2017-02-01

D(-)-lactic acid is needed for manufacturing of stereo-complex poly-lactic acid polymer. Large scale D-lactic acid fermentation, however, has yet to be demonstrated. A genetically engineered Escherichia coli strain, HBUT-D, was adaptively evolved in a 15% calcium lactate medium for improved lactate tolerance. The resulting strain, HBUT-D15, was tested at a lab scale (7 L) by fed-batch fermentation with up to 200 g L -1 of glucose, producing 184-191 g L -1 of D-lactic acid, with a volumetric productivity of 4.38 g L -1  h -1 , a yield of 92%, and an optical purity of 99.9%. The HBUT-D15 was then evaluated at a semi-industrial scale (30 m 3 ) via fed-batch fermentation with up to 160 g L -1 of glucose, producing 146-150 g L -1 of D-lactic acid, with a volumetric productivity of 3.95-4.29 g L -1  h -1 , a yield of 91-94%, and an optical purity of 99.8%. These results are comparable to that of current industrial scale L(+)-lactic acid fermentation.

A membrane-integrated fermentation reactor system: its effects in reducing the amount of sub-raw materials for D-lactic acid continuous fermentation by Sporolactobacillus laevolacticus.

PubMed

Mimitsuka, Takashi; Na, Kyungsu; Morita, Ken; Sawai, Hideki; Minegishi, Shinichi; Henmi, Masahiro; Yamada, Katsushige; Shimizu, Sakayu; Yonehara, Tetsu

2012-01-01

Continuous fermentation by retaining cells with a membrane-integrated fermentation reactor (MFR) system was found to reduce the amount of supplied sub-raw material. If the amount of sub-raw material can be reduced, continuous fermentation with the MFR system should become a more attractive process for industrialization, due to decreased material costs and loads during the refinement process. Our findings indicate that the production rate decreased when the amount of the sub-raw material was reduced in batch fermentation, but did not decrease during continuous fermentation with Sporolactobacillus laevolacticus. Moreover, continuous fermentation with a reduced amount of sub-raw material resulted in a productivity of 11.2 g/L/h over 800 h. In addition, the index of industrial process applicability used in the MFR system increased by 6.3-fold as compared with the conventional membrane-based fermentation reactor previously reported, suggesting a potential for the industrialization of this D-lactic acid continuous fermentation process.

Significance of CO2 donor on the production of succinic acid by Actinobacillus succinogenes ATCC 55618

PubMed Central

2011-01-01

Background Succinic acid is a building-block chemical which could be used as the precursor of many industrial products. The dissolved CO2 concentration in the fermentation broth could strongly regulate the metabolic flux of carbon and the activity of phosphoenolpyruvate (PEP) carboxykinase, which are the important committed steps for the biosynthesis of succinic acid by Actinobacillus succinogenes. Previous reports showed that succinic acid production could be promoted by regulating the supply of CO2 donor in the fermentation broth. Therefore, the effects of dissolved CO2 concentration and MgCO3 on the fermentation process should be investigated. In this article, we studied the impacts of gaseous CO2 partial pressure, dissolved CO2 concentration, and the addition amount of MgCO3 on succinic acid production by Actinobacillus succinogenes ATCC 55618. We also demonstrated that gaseous CO2 could be removed when MgCO3 was fully supplied. Results An effective CO2 quantitative mathematical model was developed to calculate the dissolved CO2 concentration in the fermentation broth. The highest succinic acid production of 61.92 g/L was obtained at 159.22 mM dissolved CO2 concentration, which was supplied by 40 g/L MgCO3 at the CO2 partial pressure of 101.33 kPa. When MgCO3 was used as the only CO2 donor, a maximal succinic acid production of 56.1 g/L was obtained, which was just decreased by 7.03% compared with that obtained under the supply of gaseous CO2 and MgCO3. Conclusions Besides the high dissolved CO2 concentration, the excessive addition of MgCO3 was beneficial to promote the succinic acid synthesis. This was the first report investigating the replaceable of gaseous CO2 in the fermentation of succinic acid. The results obtained in this study may be useful for reducing the cost of succinic acid fermentation process. PMID:22040346

Antifungal activity of Leuconostoc citreum and Weissella confusa in rice cakes.

PubMed

Baek, Eunjong; Kim, Hyojin; Choi, Hyejung; Yoon, Sun; Kim, Jeongho

2012-10-01

The antifungal activity of organic acids greatly improves the shelf life of bread and bakery products. However, little is known about the effect of lactic acid fermentation on fungal contamination in rice cakes. Here, we show that lactic acid fermentation in rice dough can greatly retard the growth of three fungal species when present in rice cakes, namely Cladosporium sp. YS1, Neurospora sp. YS3, and Penicillium crustosum YS2. The antifungal activity of the lactic acid bacteria against these fungi was much better than that of 0.3% calcium propionate. We found that organic acids including lactic and acetic acid, which are byproducts of lactic fermentation or can be artificially added, were the main antifungal substances. We also found that some Leuconostoc citreum and Weissella confusa strains could be good starter species for rice dough fermentation. These results imply that these lactic acid bacteria can be applicable to improve the preservation of rice cakes.

Effects of chlorpyrifos and chlorantraniliprole on fermentation quality of alfalfa (Medicago sativa L.) silage inoculated with or without Lactobacillus plantarum LP.

PubMed

Zhang, Qing; Yu, Zhu; Wang, Xianguo; Na, Risu

2017-03-01

The effects of pesticides and Lactobacillus plantarum (LP) on fermentation quality of alfalfa (Medicago sativa L.) silage were investigated. Chlorpyrifos and chlorantraniliprole were sprayed on the surface of alfalfa plants at 658.6 and 45.0 g active ingredient/ha, respectively. Alfalfa plants were harvested on day 5 post-application and ensiled with or without LP. Chlorpyrifos and chlorantraniliprole decreased the yeast count of alfalfa material (P < 0.05). Both pesticides increased the butyric acid content of alfalfa silage (P < 0.001). Chlorpyrifos increased pH and decreased lactic acid, acetic acid and short-chain fatty acid contents (P < 0.05). LP decreased pH and butyric acid content, and increased lactic acid and short-chain fatty acid contents of alfalfa silage treated with pesticides (P < 0.05). LP increased the concentration of chlorpyrifos residue in alfalfa silage (P < 0.05). Chlorpyrifos and chlorantraniliprole affected the microbial communities of the material before ensiling, especially coliform bacteria and yeast; the two pesticide residues were reduced after the fermentation of alfalfa silage and affected the fermentation process, whereas LP improved the fermentation quality of pesticides-contaminated alfalfa silage and slowed down the dissipation of chlorpyrifos. © 2016 Japanese Society of Animal Science.

Osmoadaptation of wine yeast (Saccharomyces cerevisiae) during Icewine fermentation leads to high levels of acetic acid.

PubMed

Heit, C; Martin, S J; Yang, F; Inglis, D L

2018-06-01

Volatile acidity (VA) production along with gene expression patterns, encoding enzymes involved in both acetic acid production and utilization, were investigated to relate gene expression patterns to the production of undesired VA during Icewine fermentation. Icewine juice and diluted Icewine juice were fermented using the Saccharomyces cerevisiae wine yeast K1-V1116. Acetic acid production increased sixfold during the Icewine fermentation vs the diluted juice condition, while ethyl acetate production increased 2·4-fold in the diluted fermentation relative to the Icewine. Microarray analysis profiled the transcriptional response of K1-V1116 under both conditions. ACS1 and ACS2 were downregulated 19·0-fold and 11·2-fold, respectively, in cells fermenting Icewine juice compared to diluted juice. ALD3 expression was upregulated 14·6-fold, and gene expressions involved in lipid and ergosterol synthesis decreased during Icewine fermentation. Decreased expression of ACS1 and ACS2 together with increased ALD3 expression contributes to the higher acetic acid and lower ethyl acetate levels generated by K1-V1116 fermenting under hyperosmotic stress. This work represents a more comprehensive understanding of how and why commercial wine yeast respond at the transcriptional and metabolic level during fermentation of Icewine juice, and how these responses contribute to increased acetic acid and decreased ethyl acetate production. © 2018 The Society for Applied Microbiology.

Fermentation and recovery process for lactic acid production

DOEpatents

Tsai, S.P.; Moon, S.H.; Coleman, R.

1995-11-07

A method is described for converting starch to glucose and fermenting glucose to lactic acid, including simultaneous saccharification and fermentation through use of a novel consortium of bacterial strains. 2 figs.

Valorisation of mixed bakery waste in non-sterilized fermentation for L-lactic acid production by an evolved Thermoanaerobacterium sp. strain.

PubMed

Yang, Xiaofeng; Zhu, Muzi; Huang, Xiongliang; Lin, Carol Sze Ki; Wang, Jufang; Li, Shuang

2015-12-01

In this study, an advanced biorefinery technology that uses mixed bakery waste has been developed to produce l-lactic acid using an adaptively evolved Thermoanaerobacterium aotearoense LA1002-G40 in a non-sterilized system. Under these conditions, mixed bakery waste was directly hydrolysed by Aspergillus awamori and Aspergillus oryzae, resulting in a nutrient-rich hydrolysate containing 83.6g/L glucose, 9.5 g/L fructose and 612 mg/L free amino nitrogen. T. aotearoense LA1002-G40 was evaluated and then adaptively evolved to grow in this nutrient-rich hydrolysate. Using a 5-L fermenter, the overall lactic acid production from mixed bakery waste was 0.18 g/g with a titer, productivity and yield of 78.5 g/L, 1.63 g/L/h and 0.85 g/g, respectively. This is an innovative procedure involving a complete bioconversion process for l-lactic acid produced from mixed bakery waste under non-sterilized conditions. The proposed process could be potentially applied to turn food waste into l-lactic acid in an economically feasible way. Copyright © 2015 Elsevier Ltd. All rights reserved.

Simultaneous Production and Recovery of Fumaric Acid from Immobilized Rhizopus oryzae with a Rotary Biofilm Contactor and an Adsorption Column

PubMed Central

Cao, N.; Du, J.; Gong, C. S.; Tsao, G. T.

1996-01-01

An integrated system of simultaneous fermentation-adsorption for the production and recovery of fumaric acid from glucose by Rhizopus oryzae was investigated. The system was constructed such that growing Rhizopus mycelia were self-immobilized on the plastic discs of a rotary biofilm contactor during the nitrogen-rich growth phase. During the nongrowth, production phase, the biofilm was alternately exposed to liquid medium and air upon rotation of the discs in the horizontal fermentation vessel. The product of fermentation, fumaric acid, was removed simultaneously and continuously by a coupled adsorption column, thereby moderating inhibition, enhancing the fermentation rate, and sustaining cell viability. Another beneficial effect of the removal of fumaric acid is release of hydroxyl ions from a polyvinyl pyridine adsorbent into the circulating fermentation broth. This moderates the decrease in pH that would otherwise occur. Polyvinyl pyridine and IRA-900 gave the highest loading for this type of fermentation. This fermentation system is capable of producing fumaric acid with an average yield of 85 g/liter from 100 g of glucose per liter within 20 h under repetitive fed-batch cycles. On a weight yield basis, 91% of the theoretical maximum was obtained with a productivity of 4.25 g/liter/h. This is in contrast to stirred-tank fermentation supplemented with calcium carbonate, whose average weight yield was 65% after 72 h with a productivity of 0.9 g/liter/h. The immobilized reactor was operated repetitively for 2 weeks without loss of biological activity. PMID:16535381

Simultaneous detoxification, saccharification, and ethanol fermentation of weak-acid hydrolyzates

USDA-ARS?s Scientific Manuscript database

Lignocellulosic feedstocks can be prepared for ethanol fermentation by pre-treatment with a dilute mineral acid catalyst that hydrolyzes the hemicellulose and opens up the plant cell wall fibers for subsequent enzymatic saccharification. The acid catalyzed reaction scheme is sequential whereby rele...

Lactic acid fermentation of cassava dough into agbelima.

PubMed

Amoa-Awua, W K; Appoh, F E; Jakobsen, M

1996-08-01

The souring of cassava dough during fermentation into the fermented cassava meal, agbelima, was investigated. Four different types of traditional inocula were used to ferment the dough and increases in titrable acidity expressed as lactic acid from 0.31-0.38 to 0.78-0.91% (w/w) confirmed the fermentation to be a process of acidification. The microflora of all inocula and fermenting dough contained high counts of lactic acid bacteria, 10(8)-10(9) cfu/g in all inocula and 10(7)-10(8), 10(8)-10(9) and 10(9) cfu/g at 0, 24 and 48 h in all fermentations. Lactobacillus plantarum was the dominant species of lactic acid bacteria during all types of fermentation accounting for 51% of 171 representative isolates taken from various stages of fermentation. Other major lactic acid bacteria found were Lactobacillus brevis, 16%, Leuconostoc mesenteroides, 15% and some cocci including Streptococcus spp. whose numbers decreased with fermentation time. The lactic acid bacteria were responsible for the souring of agbelima through the production of lactic acid. All L. plantarum, L. brevis and L. mesenteroides isolates examined demonstrated linamarase as well as other enzymatic activities but did not possess tissue degrading enzymes like cellulase, pectin esterase and polygalacturonase. The aroma profile of agbelima did not vary with the type of inoculum used and in all samples the build-up of aroma compounds were dominated by a non-identified low molecular weight alcohol, 1-propanol, isoamyl alcohol, ethyl acetate, 3-methyl-1-butanol and acetoin. Substantial reductions occurred in the levels of cyanogenic compounds present in cassava during fermentation into agbelima and detoxification was enhanced by the use of inoculum.

Effects of end products on fermentation profiles in Clostridium carboxidivorans P7 for syngas fermentation.

PubMed

Zhang, Jie; Taylor, Steven; Wang, Yi

2016-10-01

Clostridium carboxidivorans P7 is a strict anaerobic bacterium capable of converting syngas to biofuels. However, its fermentation profiles is poorly understood. Here, various end-products, including acetic acid, butyric acid, hexanoic acid, ethanol and butanol were supplemented to evaluate their effects on fermentation profiles in C. carboxidivorans at two temperatures. At 37°C, fatty acids addition likely led to more corresponding alcohols production. At 25°C, C2 and C4 fatty acids supplementation resulted in more corresponding higher fatty acids, while supplemented hexanoic acid increased yields of C2 and C4 fatty acids and hexanol. Supplementation of ethanol or butanol caused increased production of C2 and C4 acids at both temperatures; however, long-chain alcohols were still more likely produced at lower temperature. In conclusion, fermentation profiles of C. carboxidivorans can be changed in respond to pre-added end-products and carbon flow may be redirected to desired products by controlling culture conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis of microbial community variation during the mixed culture fermentation of agricultural peel wastes to produce lactic acid.

PubMed

Liang, Shaobo; Gliniewicz, Karol; Gerritsen, Alida T; McDonald, Armando G

2016-05-01

Mixed cultures fermentation can be used to convert organic wastes into various chemicals and fuels. This study examined the fermentation performance of four batch reactors fed with different agricultural (orange, banana, and potato (mechanical and steam)) peel wastes using mixed cultures, and monitored the interval variation of reactor microbial communities with 16S rRNA genes using Illumina sequencing. All four reactors produced similar chemical profile with lactic acid (LA) as dominant compound. Acetic acid and ethanol were also observed with small fractions. The Illumina sequencing results revealed the diversity of microbial community decreased during fermentation and a community of largely lactic acid producing bacteria dominated by species of Lactobacillus developed. Copyright © 2016 Elsevier Ltd. All rights reserved.

In vitro fermentation of mulberry fruit polysaccharides by human fecal inocula and impact on microbiota.

PubMed

Chen, Chun; Huang, Qiang; Fu, Xiong; Liu, Rui Hai

2016-11-09

This study investigated the in vitro fermentation of polysaccharides from Morus alba L., the contribution of its carbohydrates to the fermentation, and the effect on the composition of gut microbiota. Over 48 h of fermentation, the pH value in the fecal culture decreased from 7.12 to 6.14, and the total short chain fatty acids (SCFA) and acetic, propionic, and butyric acids all significantly increased. After 48 h of fermentation, 45.36 ± 1.36% of the total carbohydrates in the polysaccharide, including 35.72 ± 1.51% of arabinose, 23.1 ± 1.19% of galactose, 41.43 ± 1.52% of glucose, 26.36 ± 1.93% of rhamnose and 65.57 ± 1.07% of galacturic acid, were consumed. The increase in acetic and butyric acids was primarily due to the fermentation of galactose and galacturonic acid in the polysaccharide, while the increase in propionic acid resulted mainly from the fermentation of arabinose and glucose. In addition, the polysaccharide could modulate the gut microbiota composition by increasing the Bacteroidetes population and decreasing the Firmicutes population. The results may facilitate the development of food products known as prebiotics, aimed at improving gastrointestinal health.

The optimization of l-lactic acid production from sweet sorghum juice by mixed fermentation of Bacillus coagulans and Lactobacillus rhamnosus under unsterile conditions.

PubMed

Wang, Yong; Chen, Changjing; Cai, Di; Wang, Zheng; Qin, Peiyong; Tan, Tianwei

2016-10-01

The cost reduction of raw material and sterilization could increase the economic feasibility of l-lactic acid fermentation, and the development of an cost-effective and efficient process is highly desired. To improve the efficiency of open fermentation by Lactobacillus rhamnosus based on sweet sorghum juice (SSJ) and to overcome sucrose utilization deficiency of Bacillus coagulans, a mixed fermentation was developed. Besides, the optimization of pH, sugar concentration and fermentation medium were also studied. Under the condition of mixed fermentation and controlled pH, a higher yield of 96.3% was achieved, compared to that (68.8%) in sole Lactobacillus rhamnosus fermentation. With an optimized sugar concentration and a stepwise-controlled pH, the l-lactic acid titer, yield and productivity reached 121gL(-1), 94.6% and 2.18gL(-1)h(-1), respectively. Furthermore, corn steep powder (CSP) as a cheap source of nitrogen and salts was proved to be an efficient supplement to SSJ in this process. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simultaneous saccharification and aerobic fermentation of high titer cellulosic citric acid by filamentous fungus Aspergillus niger.

PubMed

Hou, Weiliang; Bao, Jie

2018-04-01

Simultaneous saccharification and fermentation (SSF) is the most efficient operation in biorefining conversion, but aerobic SSF under high solids loading significantly faces the serious oxygen transfer limitation. This study took the first insight into an aerobic SSF by high oxygen demanding filamentous fungi in highly viscous lignocellulose hydrolysate. The results show that oxygen requirement in the aerobic SSF by Aspergillus niger was well satisfied for production of cellulosic citric acid. The record high citric acid titer of 136.3 g/L and the overall conversion yield of 74.9% of cellulose were obtained by the aerobic SSF. The advantage of SSF to the separate hydrolysis and fermentation (SHF) on citric acid fermentation was compared based on the rigorous Aspen Plus modeling. The techno-economic analysis indicates that the minimum citric acid selling price (MCSP) of $0.603 per kilogram by SSF was highly competitive with the commercial citric acid from starch feedstock. Copyright © 2018 Elsevier Ltd. All rights reserved.

Production of fuel ethanol from bamboo by concentrated sulfuric acid hydrolysis followed by continuous ethanol fermentation.

PubMed

Sun, Zhao-Yong; Tang, Yue-Qin; Iwanaga, Tomohiro; Sho, Tomohiro; Kida, Kenji

2011-12-01

An efficient process for the production of fuel ethanol from bamboo that consisted of hydrolysis with concentrated sulfuric acid, removal of color compounds, separation of acid and sugar, hydrolysis of oligosaccharides and subsequent continuous ethanol fermentation was developed. The highest sugar recovery efficiency was 81.6% when concentrated sulfuric acid hydrolysis was carried out under the optimum conditions. Continuous separation of acid from the saccharified liquid after removal of color compounds with activated carbon was conducted using an improved simulated moving bed (ISMB) system, and 98.4% of sugar and 90.5% of acid were recovered. After oligosaccharide hydrolysis and pH adjustment, the unsterilized saccharified liquid was subjected to continuous ethanol fermentation using Saccharomycescerevisiae strain KF-7. The ethanol concentration, the fermentation yield based on glucose and the ethanol productivity were approximately 27.2 g/l, 92.0% and 8.2 g/l/h, respectively. These results suggest that the process is effective for production of fuel ethanol from bamboo. Copyright © 2011 Elsevier Ltd. All rights reserved.

Cost-effective simultaneous saccharification and fermentation of l-lactic acid from bagasse sulfite pulp by Bacillus coagulans CC17.

PubMed

Zhou, Jie; Ouyang, Jia; Xu, Qianqian; Zheng, Zhaojuan

2016-12-01

The main barriers to cost-effective lactic acid production from lignocellulose are the high cost of enzymes and the ineffective utilization of the xylose within the hydrolysate. In the present study, the thermophilic Bacillus coagulans strain CC17 was used for the simultaneous saccharification and fermentation (SSF) of bagasse sulfite pulp (BSP) to produce l-lactic acid. Unexpectedly, SSF by CC17 required approximately 33.33% less fungal cellulase than did separate hydrolysis and fermentation (SHF). More interestingly, CC17 can co-ferment cellobiose and xylose without any exogenous β-glucosidase in SSF. Moreover, adding xylanase could increase the concentration of lactic acid produced via SSF. Up to 110g/L of l-lactic acid was obtained using fed-batch SSF, resulting in a lactic acid yield of 0.72g/g cellulose. These results suggest that SSF using CC17 has a remarkable advantage over SHF and that a potentially low-cost and highly-efficient fermentation process can be established using this protocol. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anaerobic detoxification fermentation by Rhodospirillum rubrum for rice straw as feed with moderate pretreatment.

PubMed

Zhang, Jian; Yuan, Jie; Zhang, Wen-Xue; Tu, Fang; Jiang, Ya; Sun, Chuan-Ze

2018-01-02

A novel and effective process was put forward for converting rice straw into feed by combining diluted acid hydrolysis and ammonization with Rhodospirillum rubrum fermentation. After pretreatment with dilute sulfuric or phosphoric acid (1%, w/w) at 100°C, materials were subjected to fermentation under several gases (N 2 , CO 2 , and air) and different light intensities in a 2-L fermentor. The key indexes of feed for fermented materials were estimated and several toxic substances were investigated during the fermentation. Following sulfuric acid treatment, the true protein of rice straw increased from 29 to 143 g kg -1 and the crude fiber decreased from 359 to 136 g kg -1 after fermentation at 0.3 L min -1  L -1 of N 2 flow and a light intensity of 3400 lux; and following phosphoric acid treatment, the true protein increased by 286% and the crude fiber decreased by 52% after fermentation at 0.4 L min -1  L -1 of N 2 flow and a light intensity of 3000 lux. Other key contents were also improved for use as feed, and some toxic substances (i.e., furfural, hydroxymethylfurfural, acetic acid, phenol, cresol) produced by the pretreatments could be removed at low levels during the fermentations.

Detoxification of sugarcane-derived hemicellulosic hydrolysate using a lactic acid producing strain.

PubMed

Alves de Oliveira, Regiane; Vaz Rossell, Carlos Eduardo; Venus, Joachim; Cândida Rabelo, Sarita; Maciel Filho, Rubens

2018-07-20

Furfural and HMF are known for a negative impact in different bioprocesses, including lactic acid fermentation. There are already some methods described to remove these inhibitory compounds from the hydrolysates. However, these methods also reduce the yield of sugars from the hydrolysis and increase the process costs. In this work, the detoxification of sugarcane-derived hemicellulosic hydrolysate was performed by Lactobacillus plantarum during the fermentation time. At the end of the fermentation, a decrease of 98% of furfural and 86% of HMF and was observed, with a final lactic acid titer of 34.5 g/L. The simultaneous fermentation and bio-detoxification simplify the process and reduce operational costs, leading to economic competitiveness of second-generation feedstock for lactic acid production. Copyright © 2018 Elsevier B.V. All rights reserved.

Optimization of the integrated citric acid-methane fermentation process by air stripping and glucoamylase addition.

PubMed

Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Wang, Ke; Tang, Lei; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

2015-03-01

To solve the problem of extraction wastewater in citric acid industry, an integrated citric acid-methane fermentation process was proposed. In the integrated process, extraction wastewater was treated by mesophilic anaerobic digestion and then reused to make mash for the next batch of citric acid fermentation. In this study, an Aspergillus niger mutant strain exhibiting resistance to high metal ions concentration was used to eliminate the inhibition of 200 mg/L Na(+) and 300 mg/L K(+) in anaerobic digestion effluent (ADE) and citric acid production increased by 25.0 %. Air stripping was used to remove ammonium, alkalinity, and part of metal ions in ADE before making mash. In consequence, citric acid production was significantly improved but still lower by 6.1 % than the control. Results indicated that metal ions in ADE synergistically inhibited the activity of glucoamylase, thus reducing citric acid production. When 130 U/g glucoamylase was added before fermentation, citric acid production was 141.5 g/L, which was even higher than the control (140.4 g/L). This process could completely eliminate extraction wastewater discharge and reduce water resource consumption.

Contribution of the tricarboxylic acid (TCA) cycle and the glyoxylate shunt in Saccharomyces cerevisiae to succinic acid production during dough fermentation.

PubMed

Rezaei, Mohammad N; Aslankoohi, Elham; Verstrepen, Kevin J; Courtin, Christophe M

2015-07-02

Succinic acid produced by yeast during bread dough fermentation can significantly affect the rheological properties of the dough. By introducing mutations in the model S288C yeast strain, we show that the oxidative pathway of the TCA cycle and the glyoxylate shunt contribute significantly to succinic acid production during dough fermentation. More specifically, deletion of ACO1 and double deletion of ACO1 and ICL1 resulted in a 36 and 77% decrease in succinic acid levels in fermented dough, respectively. Similarly, double deletion of IDH1 and IDP1 decreased succinic acid production by 85%, while also affecting the fermentation rate. By contrast, double deletion of SDH1 and SDH2 resulted in a two-fold higher succinic acid accumulation compared to the wild-type. Deletion of fumarate reductase activity (FRD1 and OSM1) in the reductive pathway of the TCA cycle did not affect the fermentation rate and succinic acid production. The changes in the levels of succinic acid produced by mutants Δidh1Δidp1 (low level) and Δsdh1Δsdh2 (high level) in fermented dough only resulted in small pH differences, reflecting the buffering capacity of dough at a pH of around 5.1. Moreover, Rheofermentometer analysis using these mutants revealed no difference in maximum dough height and gas retention capacity with the dough prepared with S288C. The impact of the changed succinic acid profile on the organoleptic or antimicrobial properties of bread remains to be demonstrated. Copyright © 2015 Elsevier B.V. All rights reserved.

Heterologous Expression and Characterization of a Thermostable Exo-β-D-Glucosaminidase from Aspergillus oryzae.

PubMed

Wu, Dingxin; Wang, Linchun; Li, Yuwei; Zhao, Shumiao; Peng, Nan; Liang, Yunxiang

2016-02-01

An exo-β-D-glucosaminidase (AorCsxA) from Aspergillus oryzae FL402 was heterologously expressed and purified. The deduced amino acid sequence indicated that AorCsxA belonged to glycoside hydrolase family 2. AorCsxA digested colloid chitosan into glucosamine but not into chitosan oligosaccharides, demonstrating exo-β-D-glucosaminidase (CsxA) activity. AorCsxA exhibited optimal activity at pH 5.5 and 50°C; however, the enzyme expressed in Pichia pastoris (PpAorCsxA) showed much stronger thermostability at 50°C than that expressed in Escherichia coli (EcAorCsxA), which may be related to glycosylation. AorCsxA activity was inhibited by EDTA and most of the tested metal ions. A single amino acid mutation (F769W) in AorCsxA significantly enhanced the specific activity and hydrolysis velocity as revealed by comparison of Vmax and kcat values with those of the wild-type enzyme. The three-dimensional structure suggested the tightened pocket at the active site of F769W enabled efficient substrate binding. The AorCsxA gene was heterologously expressed in P. pastoris, and one transformant was found to produce 222 U/ml activity during the high-cell-density fermentation. This AorCsxA-overexpressing P. pastoris strain is feasible for large-scale production of AorCsxA.

Improved production of homo-D-lactic acid via xylose fermentation by introduction of xylose assimilation genes and redirection of the phosphoketolase pathway to the pentose phosphate pathway in L-Lactate dehydrogenase gene-deficient Lactobacillus plantarum.

PubMed

Okano, Kenji; Yoshida, Shogo; Yamada, Ryosuke; Tanaka, Tsutomu; Ogino, Chiaki; Fukuda, Hideki; Kondo, Akihiko

2009-12-01

The production of optically pure d-lactic acid via xylose fermentation was achieved by using a Lactobacillus plantarum NCIMB 8826 strain whose l-lactate dehydrogenase gene was deficient and whose phosphoketolase genes were replaced with a heterologous transketolase gene. After 60 h of fermentation, 41.2 g/liter of d-lactic acid was produced from 50 g/liter of xylose.

Glycosylceramide modifies the flavor and metabolic characteristics of sake yeast

PubMed Central

Taguchi, Seiga; Yoshizaki, Yumiko; Takamine, Kazunori

2018-01-01

In the manufacture of sake, Japanese traditional rice wine, sake yeast is fermented with koji, which is steamed rice fermented with the non-pathogenic fungus Aspergillus oryzae. During fermentation, sake yeast requires lipids, such as unsaturated fatty acids and sterols, in addition to substances provided by koji enzymes for fermentation. However, the role of sphingolipids on the brewing characteristics of sake yeast has not been studied. In this study, we revealed that glycosylceramide, one of the sphingolipids abundant in koji, affects yeast fermentation. The addition of soy, A. oryzae, and Grifola frondosa glycosylceramide conferred a similar effect on the flavor profiles of sake yeast. In particular, the addition of A. oryzae and G. frondosa glycosylceramide were very similar in terms of the decreases in ethyl caprylate and ethyl 9-decenoate. The addition of soy glycosylceramide induced metabolic changes to sake yeast such as a decrease in glucose, increases in ethanol and glycerol and changes in several amino acids and organic acids concentrations. Tricarboxylic acid (TCA) cycle, pyruvate metabolism, starch and sucrose metabolism, and glycerolipid metabolism were overrepresented in the cultures incubated with sake yeast and soy glycosylceramide. This is the first study of the effect of glycosylceramide on the flavor and metabolic profile of sake yeast. PMID:29761062

Biogenic amines in table olives. Analysis by high-performance liquid chromatography.

PubMed

Hornero-Méndez, D; Garrido-Fernández, A

1994-09-01

Biogenic amines in fermented vegetables have scarcely been studied. Available data show that in table olives and fermented cucumbers their presence is rare and any determinations made have been restricted mainly to histamine. However, some microorganisms, especially those related to spoilage, found in the fermentation brines of such products may have amino acid decarboxylase activity and give rise to biogenic amines by unusual processes. A method for the simultaneous determination of eight biogenic amines (tryptamine, beta-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, and spermine) has been developed to study their occurrence in fermented vegetables in more detail. The method consists of extraction of the amines from olive paste with 5% m/v trichloracetic acid and successive transfers into water-saturated n-BuOH and 0.1 mol l-1 HCl. An aliquot of this mixture is dried and derivatized with dansyl chloride. The dansyl derivatives are then analysed by high-performance liquid chromatography. Special emphasis has been given to optimization of the n-BuOH and 0.1 mol l-1 HCl extractions and to the derivatization conditions. By applying this method to the analysis of spoilt olives, the presence of some biogenic amines has been demonstrated. Thus a new method for monitoring the presence of biogenic amines during the fermentation of olives and for detecting anomalous fermentations is envisaged.

Production of Protein Concentrate and 1,3-Propanediol by Wheat-Based Thin Stillage Fermentation.

PubMed

Ratanapariyanuch, Kornsulee; Shim, Youn Young; Emami, Shahram; Reaney, Martin J T

2017-05-17

Fermentation of wheat with yeast produces thin stillage (W-TS) and distiller's wet grains. A subsequent fermentation of W-TS (two-stage fermentation, TSF) with endemic bacteria at 25 and 37 °C decreased glycerol and lactic acid concentrations, while 1,3-propanediol (1,3-PD) and acetic acid accumulated with greater 1,3-PD and acetic acid produced at 37 °C. During TSF, W-TS colloids coagulated and floated in the fermentation medium producing separable liquid and slurry fractions. The predominant endemic bacteria in W-TS were Lactobacillus panis, L. gallinarum, and L. helveticus, and this makeup did not change substantially as fermentation progressed. As nutrients were exhausted, floating particles precipitated. Protein contents of slurry and clarified liquid increased and decreased, respectively, as TSF progressed. The liquid was easily filtered through an ultrafiltration membrane. These results suggested that TSF is a novel method for W-TS clarification and production of protein concentrates and 1,3-PD from W-TS.

Nitrogen fertilisation increases biogenic amines and amino acid concentrations in Vitis vinifera var. Riesling musts and wines.

PubMed

Smit, Inga; Pfliehinger, Marco; Binner, Antonie; Großmann, Manfred; Horst, Walter J; Löhnertz, Otmar

2014-08-01

Wines rich in biogenic amines can cause adverse health effects to the consumer. Being nitrogen-containing substances, the amount of amines in wines might be strongly influenced by the rate of nitrogen fertiliser application during grape production. The aim of this work was to evaluate the effect of nitrogen fertilisation in the vineyard on the formation of biogenic amines in musts and wines. In a field experiment which compared unfertilised and fertilised (60 and 150 kg N ha(-1)) vines over two separate years, the total amine concentrations in must and wine increased. The latter was due to an increase of individual amines such as ethylamine, histamine, isopentylamine, phenylethylamine and spermidine in the musts and wines with the nitrogen application. Furthermore, the fermentation process increased the concentration of histamine and ethylamine in most of the treatments, while spermidine, spermine and isopentylamine concentrations generally decreased. Throughout both vintages, the concentrations of tyramine and histamine of the investigated musts and wines never reached detrimental levels to the health of non-allergenic people. Nitrogen fertilisation has a significant effect on amines formation in musts and wines. Furthermore, during fermentation, ethylamine and histamine increased while other amines were presumably serving as N sources during fermentation. © 2013 Society of Chemical Industry.

Glycosylceramide modifies the flavor and metabolic characteristics of sake yeast.

PubMed

Ferdouse, Jannatul; Yamamoto, Yuki; Taguchi, Seiga; Yoshizaki, Yumiko; Takamine, Kazunori; Kitagaki, Hiroshi

2018-01-01

In the manufacture of sake, Japanese traditional rice wine, sake yeast is fermented with koji, which is steamed rice fermented with the non-pathogenic fungus Aspergillus oryzae . During fermentation, sake yeast requires lipids, such as unsaturated fatty acids and sterols, in addition to substances provided by koji enzymes for fermentation. However, the role of sphingolipids on the brewing characteristics of sake yeast has not been studied. In this study, we revealed that glycosylceramide, one of the sphingolipids abundant in koji, affects yeast fermentation. The addition of soy, A. oryzae , and Grifola frondosa glycosylceramide conferred a similar effect on the flavor profiles of sake yeast. In particular, the addition of A. oryzae and G. frondosa glycosylceramide were very similar in terms of the decreases in ethyl caprylate and ethyl 9-decenoate. The addition of soy glycosylceramide induced metabolic changes to sake yeast such as a decrease in glucose, increases in ethanol and glycerol and changes in several amino acids and organic acids concentrations. Tricarboxylic acid (TCA) cycle, pyruvate metabolism, starch and sucrose metabolism, and glycerolipid metabolism were overrepresented in the cultures incubated with sake yeast and soy glycosylceramide. This is the first study of the effect of glycosylceramide on the flavor and metabolic profile of sake yeast.

Scaleable production and separation of fermentation-derived acetic acid. Final CRADA report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snyder, S. W.; Energy Systems

2010-02-08

Half of U.S. acetic acid production is used in manufacturing vinyl acetate monomer (VAM) and is economical only in very large production plants. Nearly 80% of the VAM is produced by methanol carbonylation, which requires high temperatures and exotic construction materials and is energy intensive. Fermentation-derived acetic acid production allows for small-scale production at low temperatures, significantly reducing the energy requirement of the process. The goal of the project is to develop a scaleable production and separation process for fermentation-derived acetic acid. Synthesis gas (syngas) will be fermented to acetic acid, and the fermentation broth will be continuously neutralized withmore » ammonia. The acetic acid product will be recovered from the ammonium acid broth using vapor-based membrane separation technology. The process is summarized in Figure 1. The two technical challenges to success are selecting and developing (1) microbial strains that efficiently ferment syngas to acetic acid in high salt environments and (2) membranes that efficiently separate ammonia from the acetic acid/water mixture and are stable at high enough temperature to facilitate high thermal cracking of the ammonium acetate salt. Fermentation - Microbial strains were procured from a variety of public culture collections (Table 1). Strains were incubated and grown in the presence of the ammonium acetate product and the fastest growing cultures were selected and incubated at higher product concentrations. An example of the performance of a selected culture is shown in Figure 2. Separations - Several membranes were considered. Testing was performed on a new product line produced by Sulzer Chemtech (Germany). These are tubular ceramic membranes with weak acid functionality (see Figure 3). The following results were observed: (1) The membranes were relatively fragile in a laboratory setting; (2) Thermally stable {at} 130 C in hot organic acids; (3) Acetic acid rejection > 99%; and (4) Moderate ammonia flux. The advantages of producing acetic acid by fermentation include its appropriateness for small-scale production, lower cost feedstocks, low energy membrane-based purification, and lower temperature and pressure requirements. Potential energy savings of using fermentation are estimated to be approximately 14 trillion Btu by 2020 from a reduction in natural gas use. Decreased transportation needs with regional plants will eliminate approximately 200 million gallons of diesel consumption, for combined savings of 45 trillion Btu. If the fermentation process captures new acetic acid production, savings could include an additional 5 trillion Btu from production and 7 trillion Btu from transportation energy.« less

Enhanced solid-state citric acid bio-production using apple pomace waste through surface response methodology.

PubMed

Dhillon, G S; Brar, S K; Verma, M; Tyagi, R D

2011-04-01

  To evaluate the potential of apple pomace (AP) supplemented with rice husk for hyper citric acid production through solid-state fermentation by Aspergillus niger NRRL-567. Optimization of two key parameters, such as moisture content and inducer (ethanol and methanol) concentration was carried out by response surface methodology.   In this study, the effect of two crucial process parameters for solid-state citric acid fermentation by A. niger using AP waste supplemented with rice husk were thoroughly investigated in Erlenmeyer flasks through response surface methodology. Moisture and methanol had significant positive effect on citric acid production by A. niger grown on AP (P < 0·05). Higher values of citric acid on AP by A. niger (342·41gkg(-1) and 248·42gkg(-1) dry substrate) were obtained with 75% (v/w) moisture along with two inducers [3% (v/w) methanol and 3% (v/w) ethanol] with fermentation efficiency of 93·90% and 66·42%, respectively depending upon the total carbon utilized after 144h of incubation period. With the same optimized parameters, conventional tray fermentation was conducted. The citric acid concentration of 187·96gkg(-1) dry substrate with 3% (v/w) ethanol and 303·34gkg(-1) dry substrate with 3% (v/w) methanol were achieved representing fermentation efficiency of 50·80% and 82·89% in tray fermentation depending upon carbon utilization after 120h of incubation period.   Apple pomace proved to be the promising substrate for the hyper production of citric acid through solid-state tray fermentation, which is an economical technique and does not require any sophisticated instrumentation.   The study established that the utilization of agro-industrial wastes have positive repercussions on the economy and will help to meet the increasing demands of citric acid and moreover will help to alleviate the environmental problems resulting from the disposal of agro-industrial wastes. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

Concurrent Lactic and Volatile Fatty Acid Analysis of Microbial Fermentation Samples by Gas Chromatography with Heat Pre-treatment.

PubMed

Darwin; WipaCharles; Cord-Ruwisch, Ralf

2018-01-01

Organic acid analysis of fermentation samples can be readily achieved by gas chromatography (GC), which detects volatile organic acids. However, lactic acid, a key fermentation acid is non-volatile and can hence not be quantified by regular GC analysis. However the addition of periodic acid to organic acid samples has been shown to enable lactic acid analysis by GC, as periodic acid oxidizes lactic acid to the volatile acetaldehyde. Direct GC injection of lactic acid standards and periodic acid generated inconsistent and irreproducible peaks, possibly due to incomplete lactic acid oxidation to acetaldehyde. The described method is developed to improve lactic acid analysis by GC by using a heat treated derivatization pre-treatment, such that it becomes independent of the retention time and temperature selection of the GC injector. Samples containing lactic acid were amended by periodic acid and heated in a sealed test tube at 100°C for at least 45 min before injecting it to the GC. Reproducible and consistent peaks of acetaldehyde were obtained. Simultaneous determination of lactic acid, acetone, ethanol, butanol, volatile fatty acids could also be accomplished by applying this GC method, enabling precise and convenient organic acid analysis of biological samples such as anaerobic digestion and fermentation processes. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Wastewater recycling technology for fermentation in polyunsaturated fatty acid production.

PubMed

Song, Xiaojin; Ma, Zengxin; Tan, Yanzhen; Zhang, Huidan; Cui, Qiu

2017-07-01

To reduce fermentation-associated wastewater discharge and the cost of wastewater treatment, which further reduces the total cost of DHA and ARA production, this study first analyzed the composition of wastewater from Aurantiochytrium (DHA) and Mortierella alpina (ARA) fermentation, after which wastewater recycling technology for these fermentation processes was developed. No negative effects of DHA and ARA production were observed when the two fermentation wastewater methods were cross-recycled. DHA and ARA yields were significantly inhibited when the wastewater from the fermentation process was directly reused. In 5-L fed-batch fermentation experiments, using this cross-recycle technology, the DHA and ARA yields were 30.4 and 5.13gL -1 , respectively, with no significant changes (P>0.05) compared to the control group, and the water consumption was reduced by half compared to the traditional process. Therefore, this technology has great potential in industrial fermentation for polyunsaturated fatty acid production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Increasing fermentation efficiency at high sugar concentrations by supplementing an additional source of nitrogen during the exponential phase of the tequila fermentation process.

PubMed

Arrizon, Javier; Gschaedler, Anne

2002-11-01

In the tequila industry, fermentation is traditionally achieved at sugar concentrations ranging from 50 to 100 g x L(-1). In this work, the behaviour of the Saccharomyces cerevisiae yeast (isolated from the juices of the Agave tequilana Weber blue variety) during the agave juice fermentation is compared at different sugar concentrations to determine if it is feasible for the industry to run fermentation at higher sugar concentrations. Fermentation efficiency is shown to be higher (above 90%) at a high concentration of initial sugar (170 g x L(-1)) when an additional source of nitrogen (a mixture of amino acids and ammonium sulphate, different than a grape must nitrogen composition) is added during the exponential growth phase.

Polycyclic Aromatic Hydrocarbon Affects Acetic Acid Production during Anaerobic Fermentation of Waste Activated Sludge by Altering Activity and Viability of Acetogen.

PubMed

Luo, Jingyang; Chen, Yinguang; Feng, Leiyu

2016-07-05

Till now, almost all the studies on anaerobic fermentation of waste activated sludge (WAS) for bioproducts generation focused on the influences of operating conditions, pretreatment methods and sludge characteristics, and few considered those of widespread persistent organic pollutants (POPs) in sludge, for example, polycyclic aromatic hydrocarbons (PAHs). Herein, phenanthrene, which was a typical PAH and widespread in WAS, was selected as a model compound to investigate its effect on WAS anaerobic fermentation for short-chain fatty acids (SCFAs) accumulation. Experimental results showed that the concentration of SCFAs derived from WAS was increased in the presence of phenanthrene during anaerobic fermentation. The yield of acetic acid which was the predominant SCFA in the fermentation reactor with the concentration of 100 mg/kg dry sludge was 1.8 fold of that in the control. Mechanism exploration revealed that the present phenanthrene mainly affected the acidification process of anaerobic fermentation and caused the shift of the microbial community to benefit the accumulation of acetic acid. Further investigation showed that both the activities of key enzymes (phosphotransacetylase and acetate kinase) involved in acetic acid production and the quantities of their corresponding encoding genes were enhanced in the presence of phenanthrene. Viability tests by determining the adenosine 5'-triphosphate content and membrane potential confirmed that the acetogens were more viable in anaerobic fermentation systems with phenanthrene, which resulted in the increased production of acetic acid.

L-Lactic acid production by combined utilization of agricultural bioresources as renewable and economical substrates through batch and repeated-batch fermentation of Enterococcus faecalis RKY1.

PubMed

Reddy, Lebaka Veeranjaneya; Kim, Young-Min; Yun, Jong-Sun; Ryu, Hwa-Won; Wee, Young-Jung

2016-06-01

Enterococcus faecalis RKY1 was used to produce l-lactic acid from hydrol, soybean curd residues (SCR), and malt. Hydrol was efficiently metabolized to l-lactic acid with optical purity of >97.5%, though hydrol contained mixed sugars such as glucose, maltose, maltotriose, and maltodextrin. Combined utilization of hydrol, SCR, and malt was enough to sustain lactic acid fermentation by E. faecalis RKY1. In order to reduce the amount of nitrogen sources and product inhibition, cell-recycle repeated-batch fermentation was employed, where a high cell mass (26.3g/L) was obtained. Lactic acid productivity was improved by removal of lactic acid from fermentation broth by membrane filtration and by linearly increased cell density. When the total of 10 repeated-batch fermentations were carried out using 100g/L hydrol, 150g/L SCR hydrolyzate, and 20g/L malt hydrolyzate as the main nutrients, lactic acid productivity was increased significantly from 3.20g/L/h to 6.37g/L/h. Copyright © 2016 Elsevier Ltd. All rights reserved.

CaCO3 supplementation alleviates the inhibition of formic acid on acetone/butanol/ethanol fermentation by Clostridium acetobutylicum.

PubMed

Qi, Gaoxiang; Xiong, Lian; Lin, Xiaoqing; Huang, Chao; Li, Hailong; Chen, Xuefang; Chen, Xinde

2017-01-01

To investigate the inhibiting effect of formic acid on acetone/butanol/ethanol (ABE) fermentation and explain the mechanism of the alleviation in the inhibiting effect under CaCO 3 supplementation condition. From the medium containing 50 g sugars l -1 and 0.5 g formic acid l -1 , only 0.75 g ABE l -1 was produced when pH was adjusted by KOH and fermentation ended prematurely before the transformation from acidogenesis to solventogenesis. In contrast, 11.4 g ABE l -1 was produced when pH was adjusted by 4 g CaCO 3 l -1 . The beneficial effect can be ascribed to the buffering capacity of CaCO 3 . Comparative analysis results showed that the undissociated formic acid concentration and acid production coupled with ATP and NADH was affected by the pH buffering capacity of CaCO 3 . Four millimole undissociated formic acid was the threshold at which the transformation to solventogenesis occurred. The inhibiting effect of formic acid on ABE fermentation can be alleviated by CaCO 3 supplementation due to its buffering capacity.

CHRIS: Hazardous Chemical Data

DTIC Science & Technology

1978-10-01

CPLORD-O-TOLUICIfE FAST RED Z& BASE = ’-1-ITRCAMILINE FERMENTAITION ALCOH!OL - ETHYL ALCOHOL FERMENTATION AMYL ALCOHCL -ISCANYL ALCOJIGI FERMENTATION BUTYL...ACID ETHYLENEDIAMINE IETRACETIC ACID VIC-H-XYLENOL XYLENOL VIENNA GREEN COPPER ACETOARSE1ITE VILRATHANE 4300 -CIPHENYLETHAME01ISOCYANATE (MDIl VINEGAR

Statistical optimization for improved production of cyclosporin a in solid-state fermentation.

PubMed

Survase, Shrikant A; Annapure, Uday S; Singhal, Rekha S

2009-11-01

This work evaluates the effect of different amino acids on production of CyA production in solid-state fermentation that was previously optimized for different fermentation parameters by one-factor-at-a-time for the maximum production of CyA by Tolypocladium inflatum MTCC 557. Based on the Plackett-Burman design, glycerol, ammonium sulfate, FeCl3, and inoculum size were selected for further optimization by response surface methodology (RSM). After identifying effective nutrients, RSM was used to develop mathematical model equations, study responses, and establish the optimum concentrations of the key nutrients for higher CyA production. It was observed that supplementation of medium containing (% w/w) glycerol, 1.53; ammonium sulfate, 0.95; FeCl3, 0.18; and inoculum size 6.4 ml/5g yielded a maximum of 7,106 mg/kg as compared with 6,480 mg CyA/kg substrate using one factor at a time. In the second step, the effect of amino acids on the production of CyA was studied. Addition of L-valine and L-leucine in combination after 20 h of fermentation resulted in maximum production of 8,166 mg/kg.

Bioconversion Using Lactic Acid Bacteria: Ginsenosides, GABA, and Phenolic Compounds.

PubMed

Lee, Na-Kyoung; Paik, Hyun-Dong

2017-05-28

Lactic acid bacteria (LAB) are used as fermentation starters in vegetable and dairy products and influence the pH and flavors of foods. For many centuries, LAB have been used to manufacture fermented foods; therefore, they are generally regarded as safe. LAB produce various substances, such as lactic acid, β-glucosidase, and β-galactosidase, making them useful as fermentation starters. Existing functional substances have been assessed as fermentation substrates for better component bioavailability or other functions. Representative materials that were bioconverted using LAB have been reported and include minor ginsenosides, γ-aminobutyric acid, equol, aglycones, bioactive isoflavones, genistein, and daidzein, among others. Fermentation mainly involves polyphenol and polysaccharide substrates and is conducted using bacterial strains such as Streptococcus thermophilus, Lactobacillus plantarum, and Bifidobacterium sp. In this review, we summarize recent studies of bioconversion using LAB and discuss future directions for this field.

Molecular and Biochemical Analysis of the Galactose Phenotype of Dairy Streptococcus thermophilus Strains Reveals Four Different Fermentation Profiles

PubMed Central

de Vin, Filip; Rådström, Peter; Herman, Lieve; De Vuyst, Luc

2005-01-01

Lactose-limited fermentations of 49 dairy Streptococcus thermophilus strains revealed four distinct fermentation profiles with respect to galactose consumption after lactose depletion. All the strains excreted galactose into the medium during growth on lactose, except for strain IMDOST40, which also displayed extremely high galactokinase (GalK) activity. Among this strain collection eight galactose-positive phenotypes sensu stricto were found and their fermentation characteristics and Leloir enzyme activities were measured. As the gal promoter seems to play an important role in the galactose phenotype, the galR-galK intergenic region was sequenced for all strains yielding eight different nucleotide sequences (NS1 to NS8). The gal promoter played an important role in the Gal-positive phenotype but did not determine it exclusively. Although GalT and GalE activities were detected for all Gal-positive strains, GalK activity could only be detected for two out of eight Gal-positive strains. This finding suggests that the other six S. thermophilus strains metabolize galactose via an alternative route. For each type of fermentation profile obtained, a representative strain was chosen and four complete Leloir gene clusters were sequenced. It turned out that Gal-positive strains contained more amino acid differences within their gal genes than Gal-negative strains. Finally, the biodiversity regarding lactose-galactose utilization among the different S. thermophilus strains used in this study was shown by RAPD-PCR. Five Gal-positive strains that contain nucleotide sequence NS2 in their galR-galK intergenic region were closely related. PMID:16000774

Sequential Mixed Cultures: From Syngas to Malic Acid

PubMed Central

Oswald, Florian; Dörsam, Stefan; Veith, Nicolas; Zwick, Michaela; Neumann, Anke; Ochsenreither, Katrin; Syldatk, Christoph

2016-01-01

Synthesis gas (syngas) fermentation using acetogenic bacteria is an approach for production of bulk chemicals like acetate, ethanol, butanol, or 2,3-butandiol avoiding the fuel vs. food debate by using carbon monoxide, carbon dioxide, and hydrogen from gasification of biomass or industrial waste gases. Suffering from energetic limitations, yields of C4-molecules produced by syngas fermentation are quite low compared with ABE fermentation using sugars as a substrate. On the other hand, fungal production of malic acid has high yields of product per gram metabolized substrate but is currently limited to sugar containing substrates. In this study, it was possible to show that Aspergilus oryzae is able to produce malic acid using acetate as sole carbon source which is a main product of acetogenic syngas fermentation. Bioreactor cultivations were conducted in 2.5 L stirred tank reactors. During the syngas fermentation part of the sequential mixed culture, Clostridium ljungdahlii was grown in modified Tanner medium and sparged with 20 mL/min of artificial syngas mimicking a composition of clean syngas from entrained bed gasification of straw (32.5 vol-% CO, 32.5 vol-% H2, 16 vol-% CO2, and 19 vol-% N2) using a microsparger. Syngas consumption was monitored via automated gas chromatographic measurement of the off-gas. For the fungal fermentation part gas sparging was switched to 0.6 L/min of air and a standard sparger. Ammonia content of medium for syngas fermentation was reduced to 0.33 g/L NH4Cl to meet the requirements for fungal production of dicarboxylic acids. Malic acid production performance of A. oryzae in organic acid production medium and syngas medium with acetate as sole carbon source was verified and gave YP∕S values of 0.28 g/g and 0.37 g/g respectively. Growth and acetate formation of C. ljungdahlii during syngas fermentation were not affected by the reduced ammonia content and 66 % of the consumed syngas was converted to acetate. The overall conversion of CO and H2 into malic acid was calculated to be 3.5 g malic acid per mol of consumed syngas or 0.22 g malic acid per gram of syngas. PMID:27445993

Simultaneous production of acetic and gluconic acids by a thermotolerant Acetobacter strain during acetous fermentation in a bioreactor.

PubMed

Mounir, Majid; Shafiei, Rasoul; Zarmehrkhorshid, Raziyeh; Hamouda, Allal; Ismaili Alaoui, Mustapha; Thonart, Philippe

2016-02-01

The activity of bacterial strains significantly influences the quality and the taste of vinegar. Previous studies of acetic acid bacteria have primarily focused on the ability of bacterial strains to produce high amounts of acetic acid. However, few studies have examined the production of gluconic acid during acetous fermentation at high temperatures. The production of vinegar at high temperatures by two strains of acetic acid bacteria isolated from apple and cactus fruits, namely AF01 and CV01, respectively, was evaluated in this study. The simultaneous production of gluconic and acetic acids was also examined in this study. Biochemical and molecular identification based on a 16s rDNA sequence analysis confirmed that these strains can be classified as Acetobacter pasteurianus. To assess the ability of the isolated strains to grow and produce acetic acid and gluconic acid at high temperatures, a semi-continuous fermentation was performed in a 20-L bioreactor. The two strains abundantly grew at a high temperature (41°C). At the end of the fermentation, the AF01 and CV01 strains yielded acetic acid concentrations of 7.64% (w/v) and 10.08% (w/v), respectively. Interestingly, CV01 was able to simultaneously produce acetic and gluconic acids during acetic fermentation, whereas AF01 mainly produced acetic acid. In addition, CV01 was less sensitive to ethanol depletion during semi-continuous fermentation. Finally, the enzymatic study showed that the two strains exhibited high ADH and ALDH enzyme activity at 38°C compared with the mesophilic reference strain LMG 1632, which was significantly susceptible to thermal inactivation. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

METABOLISM OF ω-AMINO ACIDS V.

PubMed Central

Hardman, John K.; Stadtman, Thressa C.

1963-01-01

Hardman, John K. (National Heart Institute, National Institutes of Health, Bethesda, Md.) and Thressa C. Stadtman. Metabolism of ω-amino acids. V. Energetics of the γ-aminobutyrate fermentation by Clostridium aminobutyricum. J. Bacteriol. 85:1326–1333. 1963.—Clostridium aminobutyricum utilizes γ-aminobutyrate as its sole carbon, nitrogen, and energy source, producing ammonia, acetate, and butyrate as a result of this fermentation. Coenzyme A (CoA)-transferase, phosphotransacetylase, and acetokinase activities have been demonstrated in crude extracts of the organism; the coupling of the reactions catalyzed by these enzymes to the fermentation reactions provides a mechanism whereby C. aminobutyricum can obtain energy, in the form of adenosine triphosphate, from the decomposition of γ-aminobutyrate. Indirect evidence of additional phosphorylation, at the electron-transport level, has been obtained from molar growth yield studies and from the inhibition by 2,4-dinitrophenol of butyrate synthesis from γ-aminobutyrate and from crotonyl-CoA. PMID:14047225

Mapping Genetic Variants Underlying Differences in the Central Nitrogen Metabolism in Fermenter Yeasts

PubMed Central

García, Verónica; Salinas, Francisco; Aguilera, Omayra; Liti, Gianni; Martínez, Claudio

2014-01-01

Different populations within a species represent a rich reservoir of allelic variants, corresponding to an evolutionary signature of withstood environmental constraints. Saccharomyces cerevisiae strains are widely utilised in the fermentation of different kinds of alcoholic beverages, such as, wine and sake, each of them derived from must with distinct nutrient composition. Importantly, adequate nitrogen levels in the medium are essential for the fermentation process, however, a comprehensive understanding of the genetic variants determining variation in nitrogen consumption is lacking. Here, we assessed the genetic factors underlying variation in nitrogen consumption in a segregating population derived from a cross between two main fermenter yeasts, a Wine/European and a Sake isolate. By linkage analysis we identified 18 main effect QTLs for ammonium and amino acids sources. Interestingly, majority of QTLs were involved in more than a single trait, grouped based on amino acid structure and indicating high levels of pleiotropy across nitrogen sources, in agreement with the observed patterns of phenotypic co-variation. Accordingly, we performed reciprocal hemizygosity analysis validating an effect for three genes, GLT1, ASI1 and AGP1. Furthermore, we detected a widespread pleiotropic effect on these genes, with AGP1 affecting seven amino acids and nine in the case of GLT1 and ASI1. Based on sequence and comparative analysis, candidate causative mutations within these genes were also predicted. Altogether, the identification of these variants demonstrate how Sake and Wine/European genetic backgrounds differentially consume nitrogen sources, in part explaining independently evolved preferences for nitrogen assimilation and representing a niche of genetic diversity for the implementation of practical approaches towards more efficient strains for nitrogen metabolism. PMID:24466135

Comparative Analysis of the Antioxidant Capacities and Phenolic Compounds of Oat and Buckwheat Vinegars During Production Processes.

PubMed

Yu, Xiao; Yang, Mei; Dong, Jilin; Shen, Ruiling

2018-03-01

This study aimed to explore the dynamic changes in the antioxidant activities and phenolic acid profiles of oat and buckwheat vinegars during different production stages. The results showed that both oat and buckwheat vinegar products comparably attenuated D-galactose-induced oxidative damage in mice serum and liver, indicating no obvious dose dependence within the tested concentrations. However, oat vinegar product revealed more favorable in vitro antioxidant activities than those in buckwheat vinegar product as evaluated by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging abilities. Moreover, the alcoholic fermentation, acetic acid fermentation and fumigating induced successive increase in DPPH radical scavenging abilities and phenolic acid contents of the fermentation substrates of oat and buckwheat vinegars. Importantly, the different fermentation processes of oat and buckwheat vinegars were accompanied by the dynamic migration and transformation of specific phenolic acids across bound, esterified and free fractions. Thus, the antioxidant activities of oat and buckwheat vinegars could be improved through targeted modulation of the generation of specific phenolic acid fractions during production processes. We had evaluated the in vitro and in vivo antioxidant activities and phenolic acid contents of oat and buckwheat vinegars, and further explored the dynamic changes of bound, esterified and free phenolic acid fractions during successive fermentation processes of oat and buckwheat vinegars. This study provided the theoretical guidance for obtaining minor grain vinegar with the optimal antioxidant activities through targeted modulation of fermentation processes. © 2018 Institute of Food Technologists®.

Characterization of cucumber fermentation spoilage bacteria by enrichment culture and 16S rDNA cloning.

PubMed

Breidt, Fred; Medina, Eduardo; Wafa, Doria; Pérez-Díaz, Ilenys; Franco, Wendy; Huang, Hsin-Yu; Johanningsmeier, Suzanne D; Kim, Jae Ho

2013-03-01

Commercial cucumber fermentations are typically carried out in 40000 L fermentation tanks. A secondary fermentation can occur after sugars are consumed that results in the formation of acetic, propionic, and butyric acids, concomitantly with the loss of lactic acid and an increase in pH. Spoilage fermentations can result in significant economic loss for industrial producers. The microbiota that result in spoilage remain incompletely defined. Previous studies have implicated yeasts, lactic acid bacteria, enterobacteriaceae, and Clostridia as having a role in spoilage fermentations. We report that Propionibacterium and Pectinatus isolates from cucumber fermentation spoilage converted lactic acid to propionic acid, increasing pH. The analysis of 16S rDNA cloning libraries confirmed and expanded the knowledge gained from previous studies using classical microbiological methods. Our data show that Gram-negative anaerobic bacteria supersede Gram-positive Fermincutes species after the pH rises from around 3.2 to pH 5, and propionic and butyric acids are produced. Characterization of the spoilage microbiota is an important first step in efforts to prevent cucumber fermentation spoilage. An understanding of the microorganisms that cause commercial cucumber fermentation spoilage may aid in developing methods to prevent the spoilage from occurring. © 2013 Institute of Food Technologists®

Open fermentative production of fuel ethanol from food waste by an acid-tolerant mutant strain of Zymomonas mobilis.

PubMed

Ma, Kedong; Ruan, Zhiyong; Shui, Zongxia; Wang, Yanwei; Hu, Guoquan; He, Mingxiong

2016-03-01

The aim of present study was to develop a process for open ethanol fermentation from food waste using an acid-tolerant mutant of Zymomonas mobilis (ZMA7-2). The mutant showed strong tolerance to acid condition of food waste hydrolysate and high ethanol production performance. By optimizing fermentation parameters, ethanol fermentation with initial glucose concentration of 200 g/L, pH value around 4.0, inoculum size of 10% and without nutrient addition was considered as best conditions. Moreover, the potential of bench scales fermentation and cell reusability was also examined. The fermentation in bench scales (44 h) was faster than flask scale (48 h), and the maximum ethanol concentration and ethanol yield (99.78 g/L, 0.50 g/g) higher than that of flask scale (98.31 g/L, 0.49 g/g). In addition, the stable cell growth and ethanol production profile in five cycles successive fermentation was observed, indicating the mutant was suitable for industrial ethanol production. Copyright © 2015 Elsevier Ltd. All rights reserved.

Liquid sourdough fermentation: industrial application perspectives.

PubMed

Carnevali, P; Ciati, R; Leporati, A; Paese, M

2007-04-01

Sourdough fermentation is considered to play a key role to get improved flavour, texture, nutritional and shelf-life properties of bakery products. Since few years Barilla R&D has been focusing on liquid sourdough fermentation which may deserve several advantages with respect to traditional processes. The results showed that the micro-biota of sourdough markedly influences flavour and texture of bakery products. Particular attention has been paid to lactic acid bacteria and yeasts. Selected lactic acid bacteria and yeasts were tested in sourdough liquid fermentation as single strain or in association. The parameters of fermentations were optimized and standardized to set up a laboratory plant liquid fermentation. Only a few strains of lactic acid bacteria were found to be suitable for liquid fermentation alone or in association with yeasts. Fermentations were carried out at pilot plant and an industrial technology was developed. This work describes the results found for the organoleptic profile of an industrial bread started with liquid sourdough with respect to bakers' yeast bread without sourdough addition.

Biodiversity, ecological determinants, and metabolic exploitation of sourdough microbiota.

PubMed

De Vuyst, L; Vrancken, G; Ravyts, F; Rimaux, T; Weckx, S

2009-10-01

Sourdough is a microbial ecosystem of lactic acid bacteria (LAB) and yeasts in a matrix of mainly cereal flour and water. Culture-dependent and culture-independent microbiological analysis together with metabolite target analyses of different sourdoughs enabled to understand this complex fermentation process. It is difficult to link the species diversity of the sourdough microbiota with the (geographical) type of sourdough and the flour used, although the type and quality of the latter is the main source of autochthonous LAB in spontaneous sourdough fermentations and plays a key role in establishing stable microbial consortia within a short time. Carbohydrate fermentation targeted towards maltose catabolism, the use of external alternative electron acceptors, amino acid transamination reactions, and/or the arginine deiminase pathway are metabolic activities that favour energy production, cofactor (re)cycling, and/or tolerance towards acid stress, and hence contribute to the competitiveness and dominance of certain species of LAB found in sourdoughs. Also, microbial interactions play an important role. The availability of genome sequences for several LAB species that are of importance in sourdough as well as technological advances in the fields of functional genomics, transcriptomics, and proteomics enable new approaches to study sourdough fermentations beyond the single species level and will allow an integral analysis of the metabolic activities and interactions taking place in sourdough. Finally, the implementation of selected starter cultures in sourdough technology is of pivotal importance for the industrial production of sourdoughs to be used as flavour carrier, texture-improving, or health-promoting dough ingredient.

The Effect of Fermentation Time with Probiotic Bacteria on Organic Fertilizer as Daphnia magna Cultured Medium towards Nutrient Quality, Biomass Production and Growth Performance Enhancement

NASA Astrophysics Data System (ADS)

Endar Herawati, Vivi; Agung Nugroho, Ristiawan; Pinandoyo; Darmanto, YS; Hutabarat, Johannes

2018-02-01

The nutrient quality and growth performance of D. magna are highly depend on the organic fertilizer which is used in its culture medium. The objective of this study was to identify the best fermentation time by using probiotic bacteria on organic fertilizer as mass culture medium to improve its nutrient quality, biomass production, and growth performance. This study was conducted using completely randomized experimental design with five treatments and three repetitions. Organic fertilizers used cultured medium with chicken manure, rejected bread and tofu waste fermented by probiotic bacteria then cultured for 0, 7, 14, 21 and 28 days. The results showed that medium which used 25% chicken manure, 25% tofu waste and 50% rejected bread cultured for 28 days created the highest biomass production, population density and nutrient content of D. magna those are 233,980 ind/L for population density; 134.60 grams for biomass production, 0.574% specific growth rate; 68.06% protein content and 6.91% fat. The highest fatty acid profile is 4.83% linoleic and 3.54% linolenic acid. The highest essential amino acid is 53.94 ppm lysine. In general, the content of ammonia, DO, temperature, and pH during the study were in the good range of D. magna life. The conclusion of this research is medium which used 25% chicken manure, 25% tofu waste and 50% rejected bread cultured for 28 days created the highest biomass production, population and nutrient content of D. magna.

Novel consortium of Klebsiella variicola and Lactobacillus species enhances the functional potential of fermented dairy products by increasing the availability of branched-chain amino acids and the amount of distinctive volatiles.

PubMed

Rosales-Bravo, H; Morales-Torres, H C; Vázquez-Martínez, J; Molina-Torres, J; Olalde-Portugal, V; Partida-Martínez, L P

2017-11-01

Identify novel bacterial taxa that could increase the availability of branched-chain amino acids and the amount of distinctive volatiles during skim milk fermentation. We recovered 344 bacterial isolates from stool samples of healthy and breastfed infants. Five were selected based on their ability to produce branched-chain amino acids. Three strains were identified as Escherichia coli, one as Klebsiella pneumoniae and other as Klebsiella variicola by molecular and biochemical methods. HPLC and solid-phase microextraction with GC-MS were used for the determination of free amino acids and volatile compounds respectively. The consortium formed by K. variicola and four Lactobacillus species showed the highest production of Leu and Ile in skim milk fermentation. In addition, the production of volatile compounds, such as acetoin, ethanol, 2-nonanone, and acetic, hexanoic and octanoic acids, increased in comparison to commercial yogurt, Emmental and Gouda cheese. Also, distinctive volatiles, such as 2,3-butanediol, 4-methyl-2- hexanone and octanol, were identified. The use of K. variicola in combination with probiotic Lactobacillus species enhances the availability of Leu and Ile and the amount of distinctive volatiles during skim milk fermentation. The identified consortium increases the functional potential of fermented dairy products. © 2017 The Society for Applied Microbiology.

Release of Polyphenols Is the Major Factor Influencing the Bioconversion of Rice Straw to Lactic Acid.

PubMed

Chen, Xingxuan; Xue, Yiyun; Hu, Jiajun; Tsang, Yiu Fai; Gao, Min-Tian

2017-11-01

In this study, we found that p-coumaric acid (p-CA), ferulic acid (FA), and condensed tannins were released from rice straw during saccharification. The presence of polyphenols prolonged the lag phase and lowered the productivity of lactic acid. p-CA was identified as a key inhibitor. Tannins had a lower inhibitory effect than p-CA; FA had little inhibitory effect. Acid, alkaline, and ball milling pretreatments elicited different levels of polyphenol release from rice straw. Due to the different levels of polyphenol release in the pretreatment step, the enzymatic hydrolysates contained different concentrations of polyphenols. Compared with fermentation with a synthetic medium, fermentation with the hydrolysates of ball-milled rice straw provided much lower productivity and yield of lactic acid due to the presence of polyphenols. Removal of these compounds played an important role in lactic acid fermentation. When rice straw was alkaline pretreated, the hydrolysates contained few phenolic compounds, resulting in high productivity and yield of lactic acid (1.8 g/L/h and 26.7 g/100 g straw), which were comparable to those in a synthetic medium. This indicates that there is a correlation between removal of phenolic compounds and efficiency in lactic acid fermentation.

Reducing cassava toxicity by heap-fermentation in Uganda.

PubMed

Essers, A J; Ebong, C; van der Grift, R M; Nout, M J; Otim-Nape, W; Rosling, H

1995-05-01

Processing of cassava roots by the Alur tribe in Uganda includes a stage of solid substrate fermentation in heaps. Changes in cyanogen levels during the process, microflora involved, and protein levels, amino acid patterns and mycotoxin contamination of the final products were studied. Processing was monitored at six rural households and repeated at laboratory site, comparing it to sun-drying. Flour samples from rural households were analysed for residual cyanogens, mutagenicity, cytotoxicity and aflatoxins. Mean (+/- SD) total cyanogen levels in flours collected at rural households were 20.3 (+/- 16.8) mg CN equivalents kg-1 dry weight in 1990 (n = 23) and 65.7 (+/- 56.7) in 1992 (n = 21). Mean (+/- SD) levels of cyanohydrins plus HCN were 9.1 (+/- 8.7) in the 1992 flours. Total cyanogen levels in the village monitored batches were reduced considerably by heap-fermentation from 436.3 (+/- 140.7) to 20.4 (+/- 14.0) mg CN equivalents kg-1 dry weight cassava. Residual cyanogen levels were positively correlated with particle size of the resulting crumbs. Heap-fermentation was significantly more effective in reducing cyanogen levels than sun-drying alone, but did not always result in innocuous levels of of cyanogens. Dominant mycelial growth was from the fungi Neurospora sitophila, Geotrichum candidum and Rhizopus oryzae. No mutagenicity, cytotoxicity nor aflatoxins could be detected in the flours. Protein quantity and quality were not significantly reduced. Cassava gel viscosity pattern was modified to the consumers' preference by this method. As the removal of cyanogens was more efficient and we found no new obvious health risk, heap-fermentation can be regarded as an improvement compared to sun-drying alone in areas where cassava varieties with higher cyanogen levels prevail, but we recommend optimisation of the process for ensuring still safer products.

Electricity and H2 generation from hemicellulose by sequential fermentation and microbial fuel/electrolysis cell

NASA Astrophysics Data System (ADS)

Yan, Di; Yang, Xuewei; Yuan, Wenqiao

2015-09-01

Electricity and hydrogen generation by bacteria Geobacter sulfurreducens in a dual-chamber microbial fuel/electrolysis cell following the fermentation of hemicellulose by bacteria Moorella thermoacetica was investigated. Experimental results showed that 10 g l-1 xylose under 60 °C was appropriate for the fermentation of xylose by M. thermoacetica, yielding 0.87 g-acetic acid per gram of xylose consumed. Corncob hydrolysate could also be fermented to produce acetic acid, but with lower yield (0.74 g-acid per g-xylose). The broths of xylose and corncob hydrolysate fermented by M. thermoacetica containing acetic acid were fed to G. sulfurreducens in a dual-chamber microbial fuel/electrolysis cell for electricity and hydrogen generation. The highest open-circuit cell voltages generated were 802 and 745 mV, and hydrogen yields were 41.7 and 23.3 mmol per mol-acetate, in xylose and corncob hydrolysate fermentation broth media, respectively. The internal resistance of the microbial fuel/electrolysis cell fed with corncob hydrolysate fermentation broth (3472 Ω) was much higher than that with xylose fermentation broth (1993 Ω) or sodium acetate medium (467 Ω), which was believed to be the main cause of the variation in hydrogen yield of the three feeding media.

Waste activated sludge hydrolysis and short-chain fatty acids accumulation under mesophilic and thermophilic conditions: effect of pH.

PubMed

Zhang, Peng; Chen, Yinguang; Zhou, Qi

2009-08-01

The effect of pH (4.0-11.0) on waste activated sludge (WAS) hydrolysis and short-chain fatty acids (SCFAs) accumulation under mesophilic and thermophilic conditions were investigated. The WAS hydrolysis increased markedly in thermophilic fermentation compared to mesophilic fermentation at any pH investigated. The hydrolysis at alkaline pHs (8.0-11.0) was greater than that at acidic pHs, but both of the acidic and alkaline hydrolysis was higher than that pH uncontrolled under either mesophilic or thermophilic conditions. No matter in mesophilic or thermophilic fermentation, the accumulation of SCFAs at alkaline pHs was greater than at acidic or uncontrolled pHs. The optimum SCFAs accumulation was 0.298g COD/g volatile suspended solids (VSS) with mesophilic fermentation, and 0.368 with thermophilic fermentation, which was observed respectively at pH 9.0 and fermentation time 5 d and pH 8.0 and time 9 d. The maximum SCFAs productions reported in this study were much greater than that in the literature. The analysis of the SCFAs composition showed that acetic acid was the prevalent acid in the accumulated SCFAs at any pH investigated under both temperatures, followed by propionic acid and n-valeric acid. Nevertheless, during the entire mesophilic and thermophilic fermentation the activity of methanogens was inhibited severely at acid or alkaline pHs, and the highest methane concentration was obtained at pH 7.0 in most cases. The studies of carbon mass balance showed that during WAS fermentation the reduction of VSS decreased with the increase of pH, and the thermophilic VSS reduction was greater than the mesophilic one. Further investigation indicated that most of the reduced VSS was converted to soluble protein and carbohydrate and SCFAs in two fermentations systems, while little formed methane and carbon dioxide.

Application of response surface methodology in optimization of lactic acid fermentation of radish: effect of addition of salt, additives and growth stimulators.

PubMed

Joshi, V K; Chauhan, Arjun; Devi, Sarita; Kumar, Vikas

2015-08-01

Lactic acid fermentation of radish was conducted using various additive and growth stimulators such as salt (2 %-3 %), lactose, MgSO4 + MnSO4 and Mustard (1 %, 1.5 % and 2 %) to optimize the process. Response surface methodology (Design expert, Trial version 8.0.5.2) was applied to the experimental data for the optimization of process variables in lactic acid fermentation of radish. Out of various treatments studied, only the treatments having ground mustard had an appreciable effect on lactic acid fermentation. Both linear and quadratic terms of the variables studied had a significant effect on the responses studied. The interactions between the variables were found to contribute to the response at a significant level. The best results were obtained in the treatment with 2.5 % salt, 1.5 % lactose, 1.5 % (MgSO4 + MnSO4) and 1.5 % mustard. These optimized concentrations increased titrable acidity and LAB count, but lowered pH. The second-order polynomial regression model determined that the highest titrable acidity (1.69), lowest pH (2.49) and maximum LAB count (10 × 10(8) cfu/ml) would be obtained at these concentrations of additives. Among 30 runs conducted, run 2 has got the optimum concentration of salt- 2.5 %, lactose- 1.5 %, MgSO4 + MnSO4- 1.5 % and mustard- 1.5 % for lactic acid fermentation of radish. The values for different additives and growth stimulators optimized in this study could successfully be employed for the lactic acid fermentation of radish as a postharvest reduction tool and for product development.

Free lactic acid production under acidic conditions by lactic acid bacteria strains: challenges and future prospects.

PubMed

Singhvi, Mamata; Zendo, Takeshi; Sonomoto, Kenji

2018-05-26

Lactic acid (LA) is an important platform chemical due to its significant applications in various fields and its use as a monomer for the production of biodegradable poly(lactic acid) (PLA). Free LA production is required to get rid of CaSO 4 , a waste material produced during fermentation at neutral pH which will lead to easy purification of LA required for the production of biodegradable PLA. Additionally, there is no need to use corrosive acids to release free LA from the calcium lactate produced during neutral fermentation. To date, several attempts have been made to improve the acid tolerance of lactic acid bacteria (LAB) by using both genome-shuffling approaches and rational design based on known mechanisms of LA tolerance and gene deletion in yeast strains. However, the lack of knowledge and the complexity of acid-tolerance mechanisms have made it challenging to generate LA-tolerant strains by simply modifying few target genes. Currently, adaptive evolution has proven an efficient strategy to improve the LA tolerance of individual/engineered strains. The main objectives of this article are to summarize the conventional biotechnological LA fermentation processes to date, assess their overall economic and environmental cost, and to introduce modern LA fermentation strategies for free LA production. In this review, we provide a broad overview of free LA fermentation processes using robust LAB that can ferment in acidic environments, the obstacles to these processes and their possible solutions, and the impact on future development of free LA fermentation processes commercially.

Identification and Analysis of Novel Amino-Acid Sequence Repeats in Bacillus anthracis str. Ames Proteome Using Computational Tools

PubMed Central

Hemalatha, G. R.; Rao, D. Satyanarayana; Guruprasad, L.

2007-01-01

We have identified four repeats and ten domains that are novel in proteins encoded by the Bacillus anthracis str. Ames proteome using automated in silico methods. A “repeat” corresponds to a region comprising less than 55-amino-acid residues that occur more than once in the protein sequence and sometimes present in tandem. A “domain” corresponds to a conserved region with greater than 55-amino-acid residues and may be present as single or multiple copies in the protein sequence. These correspond to (1) 57-amino-acid-residue PxV domain, (2) 122-amino-acid-residue FxF domain, (3) 111-amino-acid-residue YEFF domain, (4) 109-amino-acid-residue IMxxH domain, (5) 103-amino-acid-residue VxxT domain, (6) 84-amino-acid-residue ExW domain, (7) 104-amino-acid-residue NTGFIG domain, (8) 36-amino-acid-residue NxGK repeat, (9) 95-amino-acid-residue VYV domain, (10) 75-amino-acid-residue KEWE domain, (11) 59-amino-acid-residue AFL domain, (12) 53-amino-acid-residue RIDVK repeat, (13) (a) 41-amino-acid-residue AGQF repeat and (b) 42-amino-acid-residue GSAL repeat. A repeat or domain type is characterized by specific conserved sequence motifs. We discuss the presence of these repeats and domains in proteins from other genomes and their probable secondary structure. PMID:17538688

Exploitation of vegetables and fruits through lactic acid fermentation.

PubMed

Di Cagno, Raffaella; Coda, Rossana; De Angelis, Maria; Gobbetti, Marco

2013-02-01

Lactic acid fermentation represents the easiest and the most suitable way for increasing the daily consumption of fresh-like vegetables and fruits. Literature data are accumulating, and this review aims at describing the main features of the lactic acid bacteria to be used for fermentation. Lactic acid bacteria are a small part of the autochthonous microbiota of vegetables and fruits. The diversity of the microbiota markedly depends on the intrinsic and extrinsic parameters of the plant matrix. Notwithstanding the reliable value of the spontaneous fermentation to stabilize and preserve raw vegetables and fruits, a number of factors are in favour of using selected starters. Two main options may be pursued for the controlled lactic acid fermentation of vegetables and fruits: the use of commercial/allochthonous and the use of autochthonous starters. Several evidences were described in favour of the use of selected autochthonous starters, which are tailored for the specific plant matrix. Pro-technological, sensory and nutritional criteria for selecting starters were reported as well as several functional properties, which were recently ascribed to autochthonous lactic acid bacteria. The main features of the protocols used for the manufacture of traditional, emerging and innovative fermented vegetables and fruits were reviewed. Tailored lactic acid bacteria starters completely exploit the potential of vegetables and fruits, which enhances the hygiene, sensory, nutritional and shelf life properties. Copyright © 2012 Elsevier Ltd. All rights reserved.

Nucleic acids encoding antifungal polypeptides and uses thereof

DOEpatents

Altier, Daniel J.; Ellanskaya, I. A.; Gilliam, Jacob T.; Hunter-Cevera, Jennie; Presnail, James K; Schepers, Eric; Simmons, Carl R.; Torok, Tamas; Yalpani, Nasser

2010-11-02

Compositions and methods for protecting a plant from a pathogen, particularly a fungal pathogen, are provided. Compositions include an amino acid sequence, and variants and fragments thereof, for an antipathogenic polypeptide that was isolated from a fungal fermentation broth. Nucleic acid molecules that encode the antipathogenic polypeptides of the invention, and antipathogenic domains thereof, are also provided. A method for inducing pathogen resistance in a plant using the nucleotide sequences disclosed herein is further provided. The method comprises introducing into a plant an expression cassette comprising a promoter operably linked to a nucleotide sequence that encodes an antipathogenic polypeptide of the invention. Compositions comprising an antipathogenic polypeptide or a transformed microorganism comprising a nucleic acid of the invention in combination with a carrier and methods of using these compositions to protect a plant from a pathogen are further provided. Transformed plants, plant cells, seeds, and microorganisms comprising a nucleotide sequence that encodes an antipathogenic polypeptide of the invention are also disclosed.

High-Throughput rRNA Gene Sequencing Reveals High
and Complex Bacterial Diversity Associated with
Brazilian Coffee Bean Fermentation

PubMed Central

Vinícius de Melo, Gilberto

2018-01-01

Summary Coffee bean fermentation is a spontaneous, on-farm process involving the action of different microbial groups, including bacteria and fungi. In this study, high-throughput sequencing approach was employed to study the diversity and dynamics of bacteria associated with Brazilian coffee bean fermentation. The total DNA from fermenting coffee samples was extracted at different time points, and the 16S rRNA gene with segments around the V4 variable region was sequenced by Illumina high-throughput platform. Using this approach, the presence of over eighty bacterial genera was determined, many of which have been detected for the first time during coffee bean fermentation, including Fructobacillus, Pseudonocardia, Pedobacter, Sphingomonas and Hymenobacter. The presence of Fructobacillus suggests an influence of these bacteria on fructose metabolism during coffee fermentation. Temporal analysis showed a strong dominance of lactic acid bacteria with over 97% of read sequences at the end of fermentation, mainly represented by the Leuconostoc and Lactococcus. Metabolism of lactic acid bacteria was associated with the high formation of lactic acid during fermentation, as determined by HPLC analysis. The results reported in this study confirm the underestimation of bacterial diversity associated with coffee fermentation. New microbial groups reported in this study may be explored as functional starter cultures for on-farm coffee processing.

Deletion of JJJ1 improves acetic acid tolerance and bioethanol fermentation performance of Saccharomyces cerevisiae strains.

PubMed

Wu, Xuechang; Zhang, Lijie; Jin, Xinna; Fang, Yahong; Zhang, Ke; Qi, Lei; Zheng, Daoqiong

2016-07-01

To improve tolerance to acetic acid that is present in lignocellulosic hydrolysates and affects bioethanol production by Saccharomyces cerevisiae. Saccharomyces cerevisiae strains with improved tolerance to acetic acid were obtained through deletion of the JJJ1 gene. The lag phase of the JJJ1 deletion mutant BYΔJJJ1 was ~16 h shorter than that of the parent strain, BY4741, when the fermentation medium contained 4.5 g acetic acid/l. Additionally, the specific ethanol production rate of BYΔJJJ1 was increased (0.057 g/g h) compared to that of the parent strain (0.051 g/g h). Comparative transcription and physiological analyses revealed higher long chain fatty acid, trehalose, and catalase contents might be critical factors responsible for the acetic acid resistance of JJJ1 knockout strains. JJJ1 deletion improves acetic acid tolerance and ethanol fermentation performance of S. cerevisiae.

Modelling of Batch Lactic Acid Fermentation in
the Presence of Anionic Clay

PubMed Central

Jinescu, Cosmin; Aruş, Vasilica Alisa; Nistor, Ileana Denisa

2014-01-01

Summary Batch fermentation of milk inoculated with lactic acid bacteria was conducted in the presence of hydrotalcite-type anionic clay under static and ultrasonic conditions. An experimental study of the effect of fermentation temperature (t=38–43 °C), clay/milk ratio (R=1–7.5 g/L) and ultrasonic field (ν=0 and 35 kHz) on process dynamics was performed. A mathematical model was selected to describe the fermentation process kinetics and its parameters were estimated based on experimental data. A good agreement between the experimental and simulated results was achieved. Consequently, the model can be employed to predict the dynamics of batch lactic acid fermentation with values of process variables in the studied ranges. A statistical analysis of the data based on a 23 factorial experiment was performed in order to express experimental and model-regressed process responses depending on t, R and ν factors. PMID:27904318

Effect of Temperature on Chinese Rice Wine Brewing with High Concentration Presteamed Whole Sticky Rice

PubMed Central

Zhang, Hong-Tao; Xiong, Weili; Hu, Jianhua; Xu, Baoguo; Lin, Chi-Chung; Xu, Ling; Jiang, Lihua

2014-01-01

Production of high quality Chinese rice wine largely depends on fermentation temperature. However, there is no report on the ethanol, sugars, and acids kinetics in the fermentation mash of Chinese rice wine treated at various temperatures. The effects of fermentation temperatures on Chinese rice wine quality were investigated. The compositions and concentrations of ethanol, sugars, glycerol, and organic acids in the mash of Chinese rice wine samples were determined by HPLC method. The highest ethanol concentration and the highest glycerol concentration both were attained at the fermentation mash treated at 23°C. The highest peak value of maltose (90 g/L) was obtained at 18°C. Lactic acid and acetic acid both achieved maximum values at 33°C. The experimental results indicated that temperature contributed significantly to the ethanol production, acid flavor contents, and sugar contents in the fermentation broth of the Chinese rice wines. PMID:24672788

Effect of Time Lenght Fermentation to Katsuobushi Oxidation Rate As Fish Flavor Based

NASA Astrophysics Data System (ADS)

Amalia, U.; Rianingsih, L.; Wijayanti, I.

2018-02-01

Katsuobushi or dried smoked skipjack had a distinctive flavor and widely used in traditional Japanese cuisine. This study aimed to evaluate the oxidation rate of Katsuobushi with different lenght fermentation. The processing treatment of the product were the differences of fish boiling time (30 min and 60 min) and the lenght of fermentation: 1 week, 2 weeks and 3 weeks. The glutamic acid content, the oxidation rate (thiobarbituric acid and peroxide value) and Total Plate Count of katsuobushi were analyzed statistically using analysis of varians. Significant differences were found among 3 weeks of fermentation compare to 1 weeks fermentation (P < 0.05). The conclusion of this study was katsuobushi with 60 min boiling and 3 weeks fermentation was potential to be developed become basic ingredients for the fish flavor.

Effects of carbon dioxide on cell growth and propionic acid production from glycerol and glucose by Propionibacterium acidipropionici.

PubMed

Zhang, An; Sun, Jianxin; Wang, Zhongqiang; Yang, Shang-Tian; Zhou, Haiying

2015-01-01

The effects of CO2 on propionic acid production and cell growth in glycerol or glucose fermentation were investigated in this study. In glycerol fermentation, the volumetric productivity of propionic acid with CO2 supplementation reached 2.94g/L/day, compared to 1.56g/L/day without CO2. The cell growth using glycerol was also significantly enhanced with CO2. In addition, the yield and productivity of succinate, the main intermediate in Wood-Werkman cycle, increased 81% and 280%, respectively; consistent with the increased activities of pyruvate carboxylase and propionyl CoA transferase, two key enzymes in the Wood-Werkman cycle. However, in glucose fermentation CO2 had minimal effect on propionic acid production and cell growth. The carbon flux distributions using glycerol or glucose were also analyzed using a stoichiometric metabolic model. The calculated maintenance coefficient (mATP) increased 100%, which may explain the increase in the productivity of propionic acid in glycerol fermentation with CO2 supplement. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of temperature on Chinese rice wine brewing with high concentration presteamed whole sticky rice.

PubMed

Liu, Dengfeng; Zhang, Hong-Tao; Xiong, Weili; Hu, Jianhua; Xu, Baoguo; Lin, Chi-Chung; Xu, Ling; Jiang, Lihua

2014-01-01

Production of high quality Chinese rice wine largely depends on fermentation temperature. However, there is no report on the ethanol, sugars, and acids kinetics in the fermentation mash of Chinese rice wine treated at various temperatures. The effects of fermentation temperatures on Chinese rice wine quality were investigated. The compositions and concentrations of ethanol, sugars, glycerol, and organic acids in the mash of Chinese rice wine samples were determined by HPLC method. The highest ethanol concentration and the highest glycerol concentration both were attained at the fermentation mash treated at 23 °C. The highest peak value of maltose (90 g/L) was obtained at 18 °C. Lactic acid and acetic acid both achieved maximum values at 33 °C. The experimental results indicated that temperature contributed significantly to the ethanol production, acid flavor contents, and sugar contents in the fermentation broth of the Chinese rice wines.

Pretreatment of corn stover with diluted acetic acid for enhancement of acidogenic fermentation.

PubMed

Zhao, Xu; Wang, Lijuan; Lu, Xuebin; Zhang, Shuting

2014-04-01

A Box-Behnken design of response surface method was used to optimize acetic acid-catalyzed hydrothermal pretreatment of corn stover, in respect to acid concentration (0.05-0.25%), treatment time (5-15 min) and reaction temperature (180-210°C). Acidogenic fermentations with different initial pH and hydrolyzates were also measured to evaluate the optimal pretreatment conditions for maximizing acid production. The results showed that pretreatment with 0.25% acetic acid at 191°C for 7.74 min was found to be the most optimal condition for pretreatment of corn stover under which the production of acids can reach the highest level. Acidogenic fermentation with the hydrolyzate of pretreatment at the optimal condition at the initial pH=5 was shown to be butyric acid type fermentation, producing 21.84 g acetic acid, 7.246 g propionic acid, 9.170 butyric acid and 1.035 g isovaleric acid from 100g of corn stover in 900 g of water containing 2.25 g acetic acid. Copyright © 2014 Elsevier Ltd. All rights reserved.

Anaerobic Membrane Bioreactor for Continuous Lactic Acid Fermentation

PubMed Central

Fan, Rong; Ebrahimi, Mehrdad; Czermak, Peter

2017-01-01

Membrane bioreactor systems can enhance anaerobic lactic acid fermentation by reducing product inhibition, thus increasing productivity. In batch fermentations, the bioconversion of glucose is strongly inhibited in the presence of more than 100 g·L−1 lactic acid and is only possible when the product is simultaneously removed, which can be achieved by ceramic membrane filtration. The crossflow velocity is a more important determinant of flux than the transmembrane pressure. Therefore, to stabilize the performance of the membrane bioreactor system during continuous fermentation, the crossflow velocity was controlled by varying the biomass concentration, which was monitored in real-time using an optical sensor. Continuous fermentation under these conditions, thus, achieved a stable productivity of ~8 g·L−1·h−1 and the concentration of lactic acid was maintained at ~40 g·L−1 at a dilution rate of 0.2 h−1. No residual sugar was detected in the steady state with a feed concentration of 50 g·L−1. PMID:28467384

Kinetic modeling of lactic acid production from batch submerged fermentation of cheese whey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tango, M.S.A.; Ghaly, A.E.

1999-12-01

A kinetic model for the production of lactic acid through batch submerged fermentation of cheese whey using Lactobacillus helveticus was developed. The model accounts for the effect of substrate limitation, substrate inhibition, lactic acid inhibition, maintenance energy and cell death on the cell growth, substrate utilization, and lactic acid production during the fermentation process. The model was evaluated using experimental data from Tango and Ghaly (1999). The predicted results obtained from the model compared well with experimental (R{sup 2} = 0.92--0.98). The model was also used to investigate the effect of the initial substrate concentration on the lag period, fermentationmore » time, specific growth rate, and cell productivity during batch fermentation. The maximum specific growth rate ({micro}{sub m}), the saturation constant (K{sub S}), the substrate inhibition constant (K{sub IS}), and the lactic acid inhibition constant (K{sub IP}) were found to be 0.25h{sup {minus}1}, 0.9 g/L, 250.0 g/L, and 60.0 g/L, respectively. High initial lactose concentration in cheese whey reduced both the specific growth rate and substrate utilization rate due to the substrate inhibition phenomenon. The maximum lactic acid production occurred at about 100 g/L initial lactose concentration after 40 h of fermentation. The maximum lactic acid concentration above which Lactobacillus helveticus did not grow was found to be 80.0 g/L.« less

Biosynthesis of butyric acid by Clostridium tyrobutyricum.

PubMed

Huang, Jin; Tang, Wan; Zhu, Shengquan; Du, Meini

2018-05-28

Butyric acid (C 3 H 7 COOH) is an important chemical that is widely used in foodstuffs along with in the chemical and pharmaceutical industries. The bioproduction of butyric acid through large-scale fermentation has the potential to be more economical and efficient than petrochemical synthesis. In this paper, the metabolic pathways involved in the production of butyric acid from Clostridium tyrobutyricum using hexose and pentose as substrates are investigated, and approaches to enhance butyric acid production through genetic modification are discussed. Finally, bioreactor modifications (including fibrous bed bioreactor, inner disk-shaped matrix bioreactor, fibrous matrix packed in porous levitated sphere carriers), low-cost feedstocks, and special treatments (including continuous fermentation with cell recycling, extractive fermentation with solvent, using different artificial electron carriers) intended to improve the feasibility of commercial butyric acid bioproduction are summarized.

Ethanol addition enhances acid treatment to eliminate Lactobacillus fermentum from the fermentation process for fuel ethanol production.

PubMed

Costa, M A S; Cerri, B C; Ceccato-Antonini, S R

2018-01-01

Fermentation is one of the most critical steps of the fuel ethanol production and it is directly influenced by the fermentation system, selected yeast, and bacterial contamination, especially from the genus Lactobacillus. To control the contamination, the industry applies antibiotics and biocides; however, these substances can result in an increased cost and environmental problems. The use of the acid treatment of cells (water-diluted sulphuric acid, adjusted to pH 2·0-2·5) between the fermentation cycles is not always effective to combat the bacterial contamination. In this context, this study aimed to evaluate the effect of ethanol addition to the acid treatment to control the bacterial growth in a fed-batch system with cell recycling, using the industrial yeast strain Saccharomyces cerevisiae PE-2. When only the acid treatment was used, the population of Lactobacillus fermentum had a 3-log reduction at the end of the sixth fermentation cycle; however, when 5% of ethanol was added to the acid solution, the viability of the bacterium was completely lost even after the first round of cell treatment. The acid treatment +5% ethanol was able to kill L. fermentum cells without affecting the ethanol yield and with a low residual sugar concentration in the fermented must. In Brazilian ethanol-producing industry, water-diluted sulphuric acid is used to treat the cell mass at low pH (2·0) between the fermentative cycles. This procedure reduces the number of Lactobacillus fermentum from 10 7 to 10 4  CFU per ml. However, the addition of 5% ethanol to the acid treatment causes the complete loss of bacterial cell viability in fed-batch fermentation with six cell recycles. The ethanol yield and yeast cell viability are not affected. These data indicate the feasibility of adding ethanol to the acid solution replacing the antibiotic use, offering a low cost and a low amount of residue in the biomass. © 2017 The Society for Applied Microbiology.

Thermophilic Dry Methane Fermentation of Distillation Residue Eluted from Ethanol Fermentation of Kitchen Waste and Dynamics of Microbial Communities.

PubMed

Huang, Yu-Lian; Tan, Li; Wang, Ting-Ting; Sun, Zhao-Yong; Tang, Yue-Qin; Kida, Kenji

2017-01-01

Thermophilic dry methane fermentation is advantageous for feedstock with high solid content. Distillation residue with 65.1 % moisture content was eluted from ethanol fermentation of kitchen waste and subjected to thermophilic dry methane fermentation, after adjusting the moisture content to 75 %. The effect of carbon to nitrogen (C/N) ratio on thermophilic dry methane fermentation was investigated. Results showed that thermophilic dry methane fermentation could not be stably performed for >10 weeks at a C/N ratio of 12.6 and a volatile total solid (VTS) loading rate of 1 g/kg sludge/d; however, it was stably performed at a C/N ratio of 19.8 and a VTS loading rate of 3 g/kg sludge/d with 83.4 % energy recovery efficiency. Quantitative PCR analysis revealed that the number of bacteria and archaea decreased by two orders of magnitude at a C/N ratio of 12.6, whereas they were not influenced at a C/N ratio of 19.8. Microbial community analysis revealed that the relative abundance of protein-degrading bacteria increased and that of organic acid-oxidizing bacteria and acetic acid-oxidizing bacteria decreased at a C/N ratio of 12.6. Therefore, there was accumulation of NH 4 + and acetic acid, which inhibited thermophilic dry methane fermentation.

The YvqE two-component system controls biofilm formation and acid production in Streptococcus pyogenes.

PubMed

Isaka, Masanori; Tatsuno, Ichiro; Maeyama, Jun-Ichi; Matsui, Hideyuki; Zhang, Yan; Hasegawa, Tadao

2016-07-01

In Streptococcus pyogenes, proteins involved in determining virulence are controlled by stand-alone response regulators and by two-component regulatory systems. Previous studies reported that, compared to the parental strain, the yvqE sensor knockout strain showed significantly reduced growth and lower virulence. To determine the function of YvqE, we performed biofilm analysis and pH assays on yvqE mutants, and site-directed mutagenesis of YvqE. The yvqE deletion mutant showed a slower acid production rate, indicating that YvqE regulates acid production from sugar fermentation. The mutant strain, in which the Asp(26) residue in YvqE was replaced with Asn, affected biofilm formation, suggesting that this amino acid senses hydrogen ions produced by fermentative sugar metabolism. Signals received by YvqE were directly or indirectly responsible for inducing pilus expression. This study shows that at low environmental pH, biofilm formation in S. pyogenes is mediated by YvqE and suggests that regulation of pilus expression by environmental acidification could be directly under the control of YvqE. © 2016 APMIS. Published by John Wiley & Sons Ltd.

Simultaneous saccharification and fermentation of acid-pretreated rapeseed meal for succinic acid production using Actinobacillus succinogenes.

PubMed

Chen, Kequan; Zhang, Han; Miao, Yelian; Wei, Ping; Chen, Jieyu

2011-04-07

Rapeseed meal was evaluated for succinic acid production by simultaneous saccharification and fermentation using Actinobacillus succinogenes ATCC 55618. Diluted sulfuric acid pretreatment and subsequent hydrolysis with pectinase was used to release sugars from rapeseed meal. The effects of culture pH, pectinase loading and yeast extract concentration on succinic acid production were investigated. When simultaneous saccharification and fermentation of diluted acid pretreated rapeseed meal with a dry matter content of 12.5% (w/v) was performed at pH 6.4 and a pectinase loading of 2% (w/w, on dry matter) without supplementation of yeast extract, a succinic acid concentration of 15.5 g/L was obtained at a yield of 12.4 g/100g dry matter. Fed-batch simultaneous saccharification and fermentation was carried out with supplementation of concentrated pretreated rapeseed meal and pectinase at 18 and 28 h to yield a final dry matter content of 20.5% and pectinase loading of 2%, with the succinic acid concentration enhanced to 23.4 g/L at a yield of 11.5 g/100g dry matter and a productivity of 0.33 g/(Lh). This study suggests that rapeseed meal may be an alternative substrate for the efficient production of succinic acid by A. succinogenes without requiring nitrogen source supplementation. Copyright © 2011 Elsevier Inc. All rights reserved.

Characterization of a recombinant flocculent Saccharomyces cerevisiae strain that co-ferments glucose and xylose: II. influence of pH and acetic acid on ethanol production.

PubMed

Matsushika, Akinori; Sawayama, Shigeki

2012-12-01

The inhibitory effects of pH and acetic acid on the co-fermentation of glucose and xylose in complex medium by recombinant flocculent Saccharomyces cerevisiae MA-R4 were evaluated. In the absence of acetic acid, the fermentation performance of strain MA-R4 was similar between pH 4.0-6.0, but was negatively affected at pH 2.5. The addition of acetic acid to batch cultures resulted in negligible inhibition of several fermentation parameters at pH 6.0, whereas the interactive inhibition of pH and acetic acid on the maximum cell and ethanol concentrations, and rates of sugar consumption and ethanol production were observed at pH levels below 5.4. The inhibitory effect of acetic acid was particularly marked for the consumption rate of xylose, as compared with that of glucose. With increasing initial acetic acid concentration, the ethanol yield slightly increased at pH 5.4 and 6.0, but decreased at pH values lower than 4.7. Notably, ethanol production was nearly completely inhibited under low pH (4.0) and high acetic acid (150-200 mM) conditions. Together, these results indicate that the inhibitory effects of acetic acid and pH on ethanol fermentation by MA-R4 are highly synergistic, although the inhibition can be reduced by increasing the medium pH.

[Isolation, identification and rumen fermentation characteristics of Propionibacterium acnes].

PubMed

Wu, Ling; Zhao, Mingjuan; Xia, Cheng; Ni, Hongbo; Zhang, Hongyou

2009-02-01

Characteristic of energy metabolism in ruminant is a negative energy balance in perinatal period. Propionic acid from ruminal microbe fermentation is a vital glyconeogenesis substrate for preventing negative energy balance. We isolated and screened a Propionibacterium acnes strain from health cow rumen fluid, and studied its rumen fermentation characteristics. A Propionibacterium acnes strain from rumen fluid of health cow with permanent rumen fistula under sterile condition was isolated by segregation procedure of anaerobic bacterium and Sodium Lactate Broth (SLB), and identified by extraction of the genome DNA, cloning of the 16S rRNA gene, and sequencing. We studied the effect of the strain on pH, volatile fatty acid and lactic acid in rumen fluid in vitro and in vivo. A bacterium isolated from health cow rumen fluid was identified as Propionibacterium acnes by morphology, biochemical characteristics and sequence homology. In vitro, pH in rumen fluid decreased to the lowest after rumen fermentation of the strain for 12 h, then increased gradually. However, concentration of volatile fatty acid, such as acetic acid, propionic acid and butyric acid, increased to the highest after rumen fermentation of the strain for 12 h, then decreased gradually in vitro. The concentration of lactic acid and ratio of acetate to propionate decreased overall in vitro. In vivo, pH in rumen fluid decreased overall, concentration, of the volatile fatty acid increased overall. A strain of Propionibacterium acnes was isolated successfully from health cow rumen fluid. It is an important basis to develop microecological preparation for preventing cows' negative energy balance in perinatal period in future.

Comparative analysis of microbial community of novel lactic acid fermentation inoculated with different undefined mixed cultures.

PubMed

Liang, Shaobo; Gliniewicz, Karol; Mendes-Soares, Helena; Settles, Matthew L; Forney, Larry J; Coats, Erik R; McDonald, Armando G

2015-03-01

Three undefined mixed cultures (activated sludge) from different municipal wastewater treatment plants were used as seeds in a novel lactic acid fermentation process fed with potato peel waste (PPW). Anaerobic sequencing batch fermenters were run under identical conditions to produce predominantly lactic acid. Illumina sequencing was used to examine the 16S rRNA genes of bacteria in the three seeds and fermenters. Results showed that the structure of microbial communities of three seeds were different. All three fermentation products had unique community structures that were dominated (>96%) by species of the genus Lactobacillus, while members of this genus constituted <0.1% in seeds. The species of Lactobacillus sp. differed among the three fermentations. Results of this study suggest the structure of microbial communities in lactic acid fermentation of PPW with undefined mixed cultures were robust and resilient, which provided engineering prospects for the microbial utilization of carbohydrate wastes to produce lactic acid. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fermentation of dilute acid pretreated Populus by Clostridium thermocellum, Caldicellulosiruptor bescii, and Caldicellulosiruptor obsidiansis

DOE PAGES

Yee, Kelsey L.; Rodriguez, Jr., Miguel; Hamilton, Choo Yieng; ...

2015-07-25

Consolidated bioprocessing (CBP), which merges enzyme production, biomass hydrolysis, and fermentation into a single step, has the potential to become an efficient and economic strategy for the bioconversion of lignocellulosic feedstocks to transportation fuels or chemicals. In this study, we evaluated Clostridium thermocellum, Caldicellulosiruptor bescii, and Caldicellulosiruptor obsidiansis, three , thermophilic,cellulolytic, mixed-acid fermenting candidate CBP microorganisms, for their fermentation capabilities using dilute acid pretreated Populus as a model biomass feedstock. Under pH controlled, anaerobic fermentation conditions, each candidate successfully digested a minimum of 75% of the cellulose from dilute acid pretreated Populus, as indicated by an increase in planktonic cellsmore » and end-product metabolites and a concurrent decrease in glucan content. C. thermocellum, which employs a cellulosomal approach to biomass degradation, required 120 hours to achieve 75% cellulose utilization. In contrast, the non-cellulosomal, secreted hydrolytic enzyme system of the Caldicellulosiruptor sp. required 300 hours to achieve similar results. End-point fermentation conversions for C. thermocellum, C. bescii, and C. obsidiansis were determined to be 0.29, 0.34, and 0.38 grams of total metabolites per gram of loaded glucan, respectively. This data provide a starting point for future strain engineering efforts that can serve to improve the biomass fermentation capabilities of these three promising candidate CBP platforms.« less

Radiation induces acid tolerance of Clostridium tyrobutyricum and enhances bioproduction of butyric acid through a metabolic switch

PubMed Central

2014-01-01

Background Butyric acid as a renewable resource has become an increasingly attractive alternative to petroleum-based fuels. Clostridium tyrobutyricum ATCC 25755T is well documented as a fermentation strain for the production of acids. However, it has been reported that butyrate inhibits its growth, and the accumulation of acetate also inhibits biomass synthesis, making production of butyric acid from conventional fermentation processes economically challenging. The present study aimed to identify whether irradiation of C. tyrobutyricum cells makes them more tolerant to butyric acid inhibition and increases the production of butyrate compared with wild type. Results In this work, the fermentation kinetics of C. tyrobutyricum cultures after being classically adapted for growth at 3.6, 7.2 and 10.8 g·L-1 equivalents were studied. The results showed that, regardless of the irradiation used, there was a gradual inhibition of cell growth at butyric acid concentrations above 10.8 g·L-1, with no growth observed at butyric acid concentrations above 3.6 g·L-1 for the wild-type strain during the first 54 h of fermentation. The sodium dodecyl sulfate polyacrylamide gel electrophoresis also showed significantly different expression levels of proteins with molecular mass around the wild-type and irradiated strains. The results showed that the proportion of proteins with molecular weights of 85 and 106 kDa was much higher for the irradiated strains. The specific growth rate decreased by 50% (from 0.42 to 0.21 h-1) and the final concentration of butyrate increased by 68% (from 22.7 to 33.4 g·L-1) for the strain irradiated at 114 AMeV and 40 Gy compared with the wild-type strains. Conclusions This study demonstrates that butyric acid production from glucose can be significantly improved and enhanced by using 12C6+ heavy ion-irradiated C. tyrobutyricum. The approach is economical, making it competitive compared with similar fermentation processes. It may prove useful as a first step in a combined method employing long-term continuous fermentation of acid-production processes. PMID:24533663

Acetobacter pasteurianus metabolic change induced by initial acetic acid to adapt to acetic acid fermentation conditions.

PubMed

Zheng, Yu; Zhang, Renkuan; Yin, Haisong; Bai, Xiaolei; Chang, Yangang; Xia, Menglei; Wang, Min

2017-09-01

Initial acetic acid can improve the ethanol oxidation rate of acetic acid bacteria for acetic acid fermentation. In this work, Acetobacter pasteurianus was cultured in ethanol-free medium, and energy production was found to increase by 150% through glucose consumption induced by initial acetic acid. However, oxidation of ethanol, instead of glucose, became the main energy production pathway when upon culturing ethanol containing medium. Proteome assay was used to analyze the metabolism change induced by initial acetic acid, which provided insight into carbon metabolic and energy regulation of A. pasteurianus to adapt to acetic acid fermentation conditions. Results were further confirmed by quantitative real-time PCR. In summary, decreased intracellular ATP as a result of initial acetic acid inhibition improved the energy metabolism to produce more energy and thus adapt to the acetic acid fermentation conditions. A. pasteurianus upregulated the expression of enzymes related to TCA and ethanol oxidation to improve the energy metabolism pathway upon the addition of initial acetic acid. However, enzymes involved in the pentose phosphate pathway, the main pathway of glucose metabolism, were downregulated to induce a change in carbon metabolism. Additionally, the enhancement of alcohol dehydrogenase expression promoted ethanol oxidation and strengthened the acetification rate, thereby producing a strong proton motive force that was necessary for energy production and cell tolerance to acetic acid.

Whole slurry saccharification and fermentation of maleic acid-pretreated rice straw for ethanol production.

PubMed

Jung, Young Hoon; Park, Hyun Min; Kim, Kyoung Heon

2015-09-01

We evaluated the feasibility of whole slurry (pretreated lignocellulose) saccharification and fermentation for producing ethanol from maleic acid-pretreated rice straw. The optimized conditions for pretreatment were to treat rice straw at a high temperature (190 °C) with 1 % (w/v) maleic acid for a short duration (3 min ramping to 190 °C and 3 min holding at 190 °C). Enzymatic digestibility (based on theoretical glucose yield) of cellulose in the pretreated rice straw was 91.5 %. Whole slurry saccharification and fermentation of pretreated rice straw resulted in 83.2 % final yield of ethanol based on the initial quantity of glucan in untreated rice straw. These findings indicate that maleic acid pretreatment results in a high yield of ethanol from fermentation of whole slurry even without conditioning or detoxification of the slurry. Additionally, the separation of solids and liquid is not required; therefore, the economics of cellulosic ethanol fuel production are significantly improved. We also demonstrated whole slurry saccharification and fermentation of pretreated lignocellulose, which has rarely been reported.

Microbiological and Physicochemical Characterization of Small-Scale Cocoa Fermentations and Screening of Yeast and Bacterial Strains To Develop a Defined Starter Culture

PubMed Central

Pereira, Gilberto Vinícius de Melo; Miguel, Maria Gabriela da Cruz Pedrozo; Ramos, Cíntia Lacerda

2012-01-01

Spontaneous cocoa bean fermentations performed under bench- and pilot-scale conditions were studied using an integrated microbiological approach with culture-dependent and culture-independent techniques, as well as analyses of target metabolites from both cocoa pulp and cotyledons. Both fermentation ecosystems reached equilibrium through a two-phase process, starting with the simultaneous growth of the yeasts (with Saccharomyces cerevisiae as the dominant species) and lactic acid bacteria (LAB) (Lactobacillus fermentum and Lactobacillus plantarum were the dominant species), which were gradually replaced by the acetic acid bacteria (AAB) (Acetobacter tropicalis was the dominant species). In both processes, a sequence of substrate consumption (sucrose, glucose, fructose, and citric acid) and metabolite production kinetics (ethanol, lactic acid, and acetic acid) similar to that of previous, larger-scale fermentation experiments was observed. The technological potential of yeast, LAB, and AAB isolates was evaluated using a polyphasic study that included the measurement of stress-tolerant growth and fermentation kinetic parameters in cocoa pulp media. Overall, strains L. fermentum UFLA CHBE8.12 (citric acid fermenting, lactic acid producing, and tolerant to heat, acid, lactic acid, and ethanol), S. cerevisiae UFLA CHYC7.04 (ethanol producing and tolerant to acid, heat, and ethanol), and Acetobacter tropicalis UFLA CHBE16.01 (ethanol and lactic acid oxidizing, acetic acid producing, and tolerant to acid, heat, acetic acid, and ethanol) were selected to form a cocktail starter culture that should lead to better-controlled and more-reliable cocoa bean fermentation processes. PMID:22636007

Efficient production of butyric acid from Jerusalem artichoke by immobilized Clostridium tyrobutyricum in a fibrous-bed bioreactor.

PubMed

Huang, Jin; Cai, Jin; Wang, Jin; Zhu, Xiangcheng; Huang, Lei; Yang, Shang-Tian; Xu, Zhinan

2011-02-01

Butyric acid is an important specialty chemical with wide industrial applications. The feasible large-scale fermentation for the economical production of butyric acid requires low-cost substrate and efficient process. In the present study, butyric acid production by immobilized Clostridium tyrobutyricum was successfully performed in a fibrous-bed bioreactor using Jerusalem artichoke as the substrate. Repeated-batch fermentation was carried out to produce butyric acid with a high butyrate yield (0.44 g/g), high productivity (2.75 g/L/h) and a butyrate concentration of 27.5 g/L. Furthermore, fed-batch fermentation using sulfuric acid pretreated Jerusalem artichoke hydrolysate resulted in a high butyric acid concentration of 60.4 g/L, with the yield of 0.38 g/g and the selectivity of ∼ 85.1 (85.1g butyric acid/g acetic acid). Thus, the production of butyric acid from Jerusalem artichoke on a commercial scale could be achieved based on the system developed in this work. Copyright © 2010. Published by Elsevier Ltd.

Evaluation of the Fermentation Potential of Pulp Mill Residue to Produce D(-)-Lactic Acid by Separate Hydrolysis and Fermentation Using Lactobacillus coryniformis subsp. torquens.

PubMed

de Oliveira Moraes, Anelize; Ramirez, Ninoska Isabel Bojorge; Pereira, Nei

2016-12-01

Lactic acid is widely used in chemical, pharmaceutical, cosmetic, and food industries, besides it is the building block to produce polylactic acid, which is a sustainable alternative biopolymer to synthetic plastic due to its biodegradability. Aiming at producing an optically pure isomer, the present work evaluated the potential of pulp mill residue as feedstock to produce D(-)-lactic acid by a strain of the bacterium Lactobacillus coryniformis subsp. torquens using separate hydrolysis and fermentation process. Enzymatic hydrolysis, optimized through response surface methodology for 1 g:4 mL solid/liquid ratio and 24.8 FPU/g cellulose enzyme loading, resulted in 140 g L -1 total reducing sugar and 110 g L -1 glucose after 48 h, leading to 61 % of efficiency. In instrumented bioreactor, 57 g L -1 of D(-)-lactic acid was achieved in 20 h of fermentation, while only 0.5 g L -1 of L(+)-lactic acid was generated. Furthermore, product yield of 0.97 g/g and volumetric productivity of 2.8 g L -1  h -1 were obtained.

Betaine Improves Polymer-Grade D-Lactic Acid Production by Sporolactobacillus inulinus Using Ammonia as Green Neutralizer.

PubMed

Lv, Guoping; Che, Chengchuan; Li, Li; Xu, Shujing; Guan, Wanyi; Zhao, Baohua; Ju, Jiansong

2017-07-06

The traditional CaCO3-based fermentation process generates huge amount of insoluble CaSO4 waste. To solve this problem, we have developed an efficient and green D-lactic acid fermentation process by using ammonia as neutralizer. The 106.7 g/L of D-lactic acid production and 0.89 g per g of consumed sugar were obtained by Sporolactobacillus inulinus CASD with a high optical purity of 99.7% by adding 100 mg/L betaine in the simple batch fermentation process. The addition of betaine was experimentally proven to protect cell at high concentration of ammonium ion, increase the D-lactate dehydrogenase specific activity and thus promote the production of D-lactic acid.

Microbiological and physicochemical characterization of small-scale cocoa fermentations and screening of yeast and bacterial strains to develop a defined starter culture.

PubMed

Pereira, Gilberto Vinícius de Melo; Miguel, Maria Gabriela da Cruz Pedrozo; Ramos, Cíntia Lacerda; Schwan, Rosane Freitas

2012-08-01

Spontaneous cocoa bean fermentations performed under bench- and pilot-scale conditions were studied using an integrated microbiological approach with culture-dependent and culture-independent techniques, as well as analyses of target metabolites from both cocoa pulp and cotyledons. Both fermentation ecosystems reached equilibrium through a two-phase process, starting with the simultaneous growth of the yeasts (with Saccharomyces cerevisiae as the dominant species) and lactic acid bacteria (LAB) (Lactobacillus fermentum and Lactobacillus plantarum were the dominant species), which were gradually replaced by the acetic acid bacteria (AAB) (Acetobacter tropicalis was the dominant species). In both processes, a sequence of substrate consumption (sucrose, glucose, fructose, and citric acid) and metabolite production kinetics (ethanol, lactic acid, and acetic acid) similar to that of previous, larger-scale fermentation experiments was observed. The technological potential of yeast, LAB, and AAB isolates was evaluated using a polyphasic study that included the measurement of stress-tolerant growth and fermentation kinetic parameters in cocoa pulp media. Overall, strains L. fermentum UFLA CHBE8.12 (citric acid fermenting, lactic acid producing, and tolerant to heat, acid, lactic acid, and ethanol), S. cerevisiae UFLA CHYC7.04 (ethanol producing and tolerant to acid, heat, and ethanol), and Acetobacter tropicalis UFLA CHBE16.01 (ethanol and lactic acid oxidizing, acetic acid producing, and tolerant to acid, heat, acetic acid, and ethanol) were selected to form a cocktail starter culture that should lead to better-controlled and more-reliable cocoa bean fermentation processes.

Unraveling Core Functional Microbiota in Traditional Solid-State Fermentation by High-Throughput Amplicons and Metatranscriptomics Sequencing.

PubMed

Song, Zhewei; Du, Hai; Zhang, Yan; Xu, Yan

2017-01-01

Fermentation microbiota is specific microorganisms that generate different types of metabolites in many productions. In traditional solid-state fermentation, the structural composition and functional capacity of the core microbiota determine the quality and quantity of products. As a typical example of food fermentation, Chinese Maotai-flavor liquor production involves a complex of various microorganisms and a wide variety of metabolites. However, the microbial succession and functional shift of the core microbiota in this traditional food fermentation remain unclear. Here, high-throughput amplicons (16S rRNA gene amplicon sequencing and internal transcribed space amplicon sequencing) and metatranscriptomics sequencing technologies were combined to reveal the structure and function of the core microbiota in Chinese soy sauce aroma type liquor production. In addition, ultra-performance liquid chromatography and headspace-solid phase microextraction-gas chromatography-mass spectrometry were employed to provide qualitative and quantitative analysis of the major flavor metabolites. A total of 10 fungal and 11 bacterial genera were identified as the core microbiota. In addition, metatranscriptomic analysis revealed pyruvate metabolism in yeasts (genera Pichia, Schizosaccharomyces, Saccharomyces , and Zygosaccharomyces ) and lactic acid bacteria (genus Lactobacillus ) classified into two stages in the production of flavor components. Stage I involved high-level alcohol (ethanol) production, with the genus Schizosaccharomyces serving as the core functional microorganism. Stage II involved high-level acid (lactic acid and acetic acid) production, with the genus Lactobacillus serving as the core functional microorganism. The functional shift from the genus Schizosaccharomyces to the genus Lactobacillus drives flavor component conversion from alcohol (ethanol) to acid (lactic acid and acetic acid) in Chinese Maotai-flavor liquor production. Our findings provide insight into the effects of the core functional microbiota in soy sauce aroma type liquor production and the characteristics of the fermentation microbiota under different environmental conditions.

Isolated nucleic acids encoding antipathogenic polypeptides and uses thereof

DOEpatents

Altier, Daniel J.; Crane, Virginia C.; Ellanskaya, Irina; Ellanskaya, Natalia; Gilliam, Jacob T.; Hunter-Cevera, Jennie; Presnail, James K.; Schepers, Eric J.; Simmons, Carl R.; Torok, Tamas; Yalpani, Nasser

2010-04-20

Compositions and methods for protecting a plant from a pathogen, particularly a fungal pathogen, are provided. Compositions include amino acid sequences, and variants and fragments thereof, for antipathogenic polypeptides that were isolated from fungal fermentation broths. Nucleic acids that encode the antipathogenic polypeptides are also provided. A method for inducing pathogen resistance in a plant using the nucleotide sequences disclosed herein is further provided. The method comprises introducing into a plant an expression cassette comprising a promoter operably linked to a nucleotide sequence that encodes an antipathogenic polypeptide of the invention. Compositions comprising an antipathogenic polypeptide or a transformed microorganism comprising a nucleic acid of the invention in combination with a carrier and methods of using these compositions to protect a plant from a pathogen are further provided. Transformed plants, plant cells, seeds, and microorganisms comprising a nucleotide sequence that encodes an antipathogenic polypeptide of the invention are also disclosed.

Freezing of meat raw materials affects tyramine and diamine accumulation in spontaneously fermented sausages.

PubMed

Bover-Cid, Sara; Miguelez-Arrizado, M Jesús; Luz Latorre Moratalla, L; Vidal Carou, M Carmen

2006-01-01

Biogenic amine accumulation was studied in spontaneously fermented sausages (Fuet) manufactured from unfrozen-fresh meat (U-sausages) and frozen-thawed meat (F-sausages). The aim was to investigate whether the frozen storage of raw materials affects the microbial composition and its aminogenic activity during sausage fermentation. Tyramine was the major amine in all sausages. Although the final levels were similar, tyramine accumulated more rapidly in F-sausages, which contained putrescine as the second amine. By contrast, U-sausages accumulated much more cadaverine than putrescine. F-sausages showed a slightly lower pH and free amino acid content as well as higher counts of technological flora (lactic acid and gram positive catalase positive bacteria) and lower counts of enterobacteria. Therefore, to freeze the meat raw materials for few days before sausage manufacture could be a useful practice, especially for the artisan fermented sausages (without starter), because it helps to reduce enterobacteria development and cadaverine production.

Acceleration of yoghurt fermentation time by yeast extract and partial characterisation of the active components.

PubMed

Smith, Esti-Andrine; Myburgh, Jacobus; Osthoff, Gernot; de Wit, Maryna

2014-11-01

Water soluble autolysate of yeast, usually utilised for microbial growth support, was used as additive in yoghurt fermentation. The yeast extract (YE) resulted in a decrease of fermentation time by 21% to reach a pH of 4·6. However, the YE resulted in unacceptable flavour and taste. By size exclusion chromatography, a fraction of the YE was obtained that could account for the observed 21% decrease in fermentation time. The fraction contained molecules of low molecular weight, consisting of minerals, free amino acids and peptides. The acceleration of the yoghurt fermentation was ascribed to the short peptides in the fraction. It is proposed that the application of this extract in industrial yoghurt manufacture would result in savings for both the industry and the consumer.

Efficient arachidonic acid-rich oil production by Mortierella alpina through a repeated fed-batch fermentation strategy.

PubMed

Ji, Xiao-Jun; Zhang, Ai-Hui; Nie, Zhi-Kui; Wu, Wen-Jia; Ren, Lu-Jing; Huang, He

2014-10-01

Arachidonic acid (ARA)-rich oil production by Mortierella alpina is a long fermentation period needed process due to the low growth rate of the filamentous fungus used. This causes the low productivity of ARA-rich oil and hinders its industrial mass scale production. In the present study, different fed-batch strategies were conducted to shorten the fermentation period. The result showed that compared with the batch culture, the fermentation period was shortened from 7days to 5days with the productivity of ARA-rich oil increased from 0.9g/(L·d) to 1.3g/(L·d) by using the fed-batch fermentation strategy. Furthermore, repeated fed-batch fermentation strategy was adopted to achieve the purpose of continuous production. By using this strategy, the fermentation period was shortened from 40days to 26days in a four cycle repeated fed-batch fermentation. This strategy proved to be convenient and economical for ARA-rich oil commercial production process. Copyright © 2014 Elsevier Ltd. All rights reserved.

Lactic acid and methane: improved exploitation of biowaste potential.

PubMed

Dreschke, G; Probst, M; Walter, A; Pümpel, T; Walde, J; Insam, H

2015-01-01

This feasibility study investigated a two-step biorefining approach to increase the value gained by recycling of organic municipal solid waste. Firstly, lactic acid was produced via batch fermentation at 37°C using the indigenous microbiome. Experiments revealed an optimal fermentation period of 24h resulting in high yields of lactic acid (up to 37gkg(-1)). The lactic acid proportion of total volatile fatty acid content reached up to 83%. Lactobacilli were selectively enriched to up to 75% of the bacterial community. Additionally conversion of organic matter to lactic acid was increased from 22% to 30% through counteracting end product inhibition by continuous lactic acid extraction. Secondly, fermentation residues were used as co-substrate in biomethane production yielding up to 618±41Nmlbiomethaneg(-1) volatile solids. Digestate, the only end product of this process can be used as organic fertilizer. Copyright © 2014 Elsevier Ltd. All rights reserved.

Chemometric evaluation of the volatile profile of probiotic melon and probiotic cashew juice.

PubMed

de Godoy Alves Filho, Elenilson; Rodrigues, Tigressa Helena Soares; Fernandes, Fabiano André Narciso; Pereira, Ana Lucia Fernandes; Narain, Narendra; de Brito, Edy Sousa; Rodrigues, Sueli

2017-09-01

The aim of this study was to evaluate the influence of the lactic acid fermentation on volatile compounds of melon and cashew apple juices. The effect of the fermentation processing on the volatile profile of probiotic juices was assessed by HS-SPME/GC-MS coupled to chemometrics with 67.9% and 81.0% of the variance in the first principal component for melon and cashew juices, respectively. The Lactobacillus casei fermentation imparted a reduction of ethyl butanoate, ethyl-2-methylbutirate, and ethyl hexanoate for melon juice; and of ethyl acetate, ethyl-2-methyl butanoate, ethyl crotonate, ethyl isovalerate, benzaldehyde, and ethyl hexanoate for cashew juice. Measurements of the stability of these compounds and the formation of the component 3-methyl-2-butenyl in melon juice may be used as a volatile marker to follow the juice fermentation. These findings suggested that even though it is not a dairy product the lactic acid fermentation of fruits developed a volatile profile combining the fruit and lactic acid fermentation volatiles with mildly formation or degradation of aroma compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

Acetic acid production from food wastes using yeast and acetic acid bacteria micro-aerobic fermentation.

PubMed

Li, Yang; He, Dongwei; Niu, Dongjie; Zhao, Youcai

2015-05-01

In this study, yeast and acetic acid bacteria strains were adopted to enhance the ethanol-type fermentation resulting to a volatile fatty acids yield of 30.22 g/L, and improve acetic acid production to 25.88 g/L, with food wastes as substrate. In contrast, only 12.81 g/L acetic acid can be obtained in the absence of strains. The parameters such as pH, oxidation reduction potential and volatile fatty acids were tested and the microbial diversity of different strains and activity of hydrolytic ferment were investigated to reveal the mechanism. The optimum pH and oxidation reduction potential for the acetic acid production were determined to be at 3.0-3.5 and -500 mV, respectively. Yeast can convert organic matters into ethanol, which is used by acetic acid bacteria to convert the organic wastes into acetic acid. The acetic acid thus obtained from food wastes micro-aerobic fermentation liquid could be extracted by distillation to get high-pure acetic acid.

Unraveling Core Functional Microbiota in Traditional Solid-State Fermentation by High-Throughput Amplicons and Metatranscriptomics Sequencing

PubMed Central

Song, Zhewei; Du, Hai; Zhang, Yan; Xu, Yan

2017-01-01

Fermentation microbiota is specific microorganisms that generate different types of metabolites in many productions. In traditional solid-state fermentation, the structural composition and functional capacity of the core microbiota determine the quality and quantity of products. As a typical example of food fermentation, Chinese Maotai-flavor liquor production involves a complex of various microorganisms and a wide variety of metabolites. However, the microbial succession and functional shift of the core microbiota in this traditional food fermentation remain unclear. Here, high-throughput amplicons (16S rRNA gene amplicon sequencing and internal transcribed space amplicon sequencing) and metatranscriptomics sequencing technologies were combined to reveal the structure and function of the core microbiota in Chinese soy sauce aroma type liquor production. In addition, ultra-performance liquid chromatography and headspace-solid phase microextraction-gas chromatography-mass spectrometry were employed to provide qualitative and quantitative analysis of the major flavor metabolites. A total of 10 fungal and 11 bacterial genera were identified as the core microbiota. In addition, metatranscriptomic analysis revealed pyruvate metabolism in yeasts (genera Pichia, Schizosaccharomyces, Saccharomyces, and Zygosaccharomyces) and lactic acid bacteria (genus Lactobacillus) classified into two stages in the production of flavor components. Stage I involved high-level alcohol (ethanol) production, with the genus Schizosaccharomyces serving as the core functional microorganism. Stage II involved high-level acid (lactic acid and acetic acid) production, with the genus Lactobacillus serving as the core functional microorganism. The functional shift from the genus Schizosaccharomyces to the genus Lactobacillus drives flavor component conversion from alcohol (ethanol) to acid (lactic acid and acetic acid) in Chinese Maotai-flavor liquor production. Our findings provide insight into the effects of the core functional microbiota in soy sauce aroma type liquor production and the characteristics of the fermentation microbiota under different environmental conditions. PMID:28769888

Recent advances in lactic acid production by microbial fermentation processes.

PubMed

Abdel-Rahman, Mohamed Ali; Tashiro, Yukihiro; Sonomoto, Kenji

2013-11-01

Fermentative production of optically pure lactic acid has roused interest among researchers in recent years due to its high potential for applications in a wide range of fields. More specifically, the sharp increase in manufacturing of biodegradable polylactic acid (PLA) materials, green alternatives to petroleum-derived plastics, has significantly increased the global interest in lactic acid production. However, higher production costs have hindered the large-scale application of PLA because of the high price of lactic acid. Therefore, reduction of lactic acid production cost through utilization of inexpensive substrates and improvement of lactic acid production and productivity has become an important goal. Various methods have been employed for enhanced lactic acid production, including several bioprocess techniques facilitated by wild-type and/or engineered microbes. In this review, we will discuss lactic acid producers with relation to their fermentation characteristics and metabolism. Inexpensive fermentative substrates, such as dairy products, food and agro-industrial wastes, glycerol, and algal biomass alternatives to costly pure sugars and food crops are introduced. The operational modes and fermentation methods that have been recently reported to improve lactic acid production in terms of concentrations, yields, and productivities are summarized and compared. High cell density fermentation through immobilization and cell-recycling techniques are also addressed. Finally, advances in recovery processes and concluding remarks on the future outlook of lactic acid production are presented. Copyright © 2013 Elsevier Inc. All rights reserved.

Influence of fermented faba bean flour on the nutritional, technological and sensory quality of fortified pasta.

PubMed

Rizzello, Carlo G; Verni, Michela; Koivula, Hanna; Montemurro, Marco; Seppa, Laila; Kemell, Marianna; Katina, Kati; Coda, Rossana; Gobbetti, Marco

2017-02-22

Faba bean has gained increasing attention from the food industry and the consumers mainly due to the quality of its protein fraction. Fermentation has been recently recognized as the most efficient tool for improving its nutritional and organoleptic properties. In this study, faba bean flour fermented with Lactobacillus plantarum DPPMAB24W was used to fortify semolina pasta. Pasta samples including different percentages of fermented faba bean flour were produced at the pilot-plant level and characterized using an integrated approach for chemical, nutritional, technological, and sensory features. At a substitution level of 30%, pasta had a more homogeneous texture and lower cooking loss compared to 50% addition. The impact of faba bean flour addition on pasta technological functionality, particularly of the protein fraction, was also assessed by scanning electron microscopy and textural profile analysis. Compared to traditional (semolina) pasta and pasta containing unfermented faba bean flour, the nutritional profile (in vitro protein digestibility and nutritional indexes - chemical score (CS), sequence of limiting essential amino acids, Essential Amino Acid Index (EAAI), Biological Value (BV), Protein Efficiency Ratio (PER), and Nutritional Index (NI)) and the resistant starch content of pasta containing 30% fermented faba bean flour markedly improved, while the starch hydrolysis rate decreased, without negatively affecting technological and sensory features. The use of fermentation technology appears to be a promising tool to enhance the quality of pasta and to promote the use of faba bean flour.

Statistical optimization of bioprocess parameters for enhanced gallic acid production from coffee pulp tannins by Penicillium verrucosum.

PubMed

Bhoite, Roopali N; Navya, P N; Murthy, Pushpa S

2013-01-01

Gallic acid (3,4,5-trihydroxybenzoic acid) was produced by microbial biotransformation of coffee pulp tannins by Penicillium verrucosum. Gallic acid production was optimized using response surface methodology (RSM) based on central composite rotatable design. Process parameters such as pH, moisture, and fermentation period were considered for optimization. Among the various fungi isolated from coffee by-products, Penicillium verrucosum produced 35.23 µg/g of gallic acid on coffee pulp as sole carbon source in solid-state fermentation. The optimum values of the parameters obtained from the RSM were pH 3.32, moisture 58.40%, and fermentation period of 96 hr. Gallic acid production with an increase of 4.6-fold was achieved upon optimization of the process parameters. The results optimized could be translated to 1-kg tray fermentation. High-performance liquid chromatography (HPLC) analysis and spectral studies such as mass spectroscopy (MS) and (1)H-nuclear magnetic resonance (NMR) confirmed that the bioactive compound isolated was gallic acid. Thus, coffee pulp, which is available in enormous quantity, could be used for the production of value-added products that can find avenues in food, pharmaceutical, and chemical industries.

Fermentation of dilute acid pretreated Populus by Clostridium thermocellum, Caldicellulosiruptor bescii, and Caldicellulosiruptor obsidiansis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yee, Kelsey L.; Rodriguez, Jr., Miguel; Hamilton, Choo Yieng

Consolidated bioprocessing (CBP), which merges enzyme production, biomass hydrolysis, and fermentation into a single step, has the potential to become an efficient and economic strategy for the bioconversion of lignocellulosic feedstocks to transportation fuels or chemicals. In this study, we evaluated Clostridium thermocellum, Caldicellulosiruptor bescii, and Caldicellulosiruptor obsidiansis, three , thermophilic,cellulolytic, mixed-acid fermenting candidate CBP microorganisms, for their fermentation capabilities using dilute acid pretreated Populus as a model biomass feedstock. Under pH controlled, anaerobic fermentation conditions, each candidate successfully digested a minimum of 75% of the cellulose from dilute acid pretreated Populus, as indicated by an increase in planktonic cellsmore » and end-product metabolites and a concurrent decrease in glucan content. C. thermocellum, which employs a cellulosomal approach to biomass degradation, required 120 hours to achieve 75% cellulose utilization. In contrast, the non-cellulosomal, secreted hydrolytic enzyme system of the Caldicellulosiruptor sp. required 300 hours to achieve similar results. End-point fermentation conversions for C. thermocellum, C. bescii, and C. obsidiansis were determined to be 0.29, 0.34, and 0.38 grams of total metabolites per gram of loaded glucan, respectively. This data provide a starting point for future strain engineering efforts that can serve to improve the biomass fermentation capabilities of these three promising candidate CBP platforms.« less