Sample records for study lactic acid
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Zhang, Caili; Zhou, Cheng; Assavasirijinda, Nilnate; Yu, Bo; Wang, Limin; Ma, Yanhe
2017-11-25
Optically pure D-lactic acid (≥ 99%) is an important precursor of polylactic acid. However, there are relatively few studies on D-lactic acid fermentation compared with the extensive investigation of L-lactic acid production. Most lactic acid producers are mesophilic organisms. Optically pure D-lactic acid produced at high temperature not only could reduce the costs of sterilization but also could inhibit the growth of other bacteria, such as L-lactic acid producers. Thermophilic Bacillus coagulans is an excellent producer of L-lactic acid with capable of growing at 50 °C. In our previous study, the roles of two L-lactic acid dehydrogenases have been demonstrated in B. coagulans DSM1. In this study, the function of another annotated possible L-lactate dehydrogenase gene (ldhL3) was verified to be leucine dehydrogenase with an activity of 0.16 units (μmol/min) per mg protein. Furthermore, the activity of native D-lactate dehydrogenase was too low to support efficient D-lactic acid production, even under the control of strong promoter. Finally, an engineered B. coagulans D-DSM1 strain with the capacity for efficient production of D-lactic acid was constructed by deletion of two L-lactate dehydrogenases genes (ldhL1 and ldhL2) and insertion of the D-lactate dehydrogenase gene (LdldhD) from Lactobacillus delbrueckii subsp. bulgaricus DSM 20081 at the position of ldhL1. This genetically engineered strain produced only D-lactic acid under non-sterilized condition, and finally 145 g/L of D-lactic acid was produced with an optical purity of 99.9% and a high yield of 0.98 g/g. This is the highest optically pure D-lactic acid titer produced by a thermophilic strain.
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Turner, Timothy L; Zhang, Guo-Chang; Kim, Soo Rin; Subramaniam, Vijay; Steffen, David; Skory, Christopher D; Jang, Ji Yeon; Yu, Byung Jo; Jin, Yong-Su
2015-10-01
Production of lactic acid from renewable sugars has received growing attention as lactic acid can be used for making renewable and bio-based plastics. However, most prior studies have focused on production of lactic acid from glucose despite that cellulosic hydrolysates contain xylose as well as glucose. Microbial strains capable of fermenting both glucose and xylose into lactic acid are needed for sustainable and economic lactic acid production. In this study, we introduced a lactic acid-producing pathway into an engineered Saccharomyces cerevisiae capable of fermenting xylose. Specifically, ldhA from the fungi Rhizopus oryzae was overexpressed under the control of the PGK1 promoter through integration of the expression cassette in the chromosome. The resulting strain exhibited a high lactate dehydrogenase activity and produced lactic acid from glucose or xylose. Interestingly, we observed that the engineered strain exhibited substrate-dependent product formation. When the engineered yeast was cultured on glucose, the major fermentation product was ethanol while lactic acid was a minor product. In contrast, the engineered yeast produced lactic acid almost exclusively when cultured on xylose under oxygen-limited conditions. The yields of ethanol and lactic acid from glucose were 0.31 g ethanol/g glucose and 0.22 g lactic acid/g glucose, respectively. On xylose, the yields of ethanol and lactic acid were <0.01 g ethanol/g xylose and 0.69 g lactic acid/g xylose, respectively. These results demonstrate that lactic acid can be produced from xylose with a high yield by S. cerevisiae without deleting pyruvate decarboxylase, and the formation patterns of fermentations can be altered by substrates.
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Amylolytic bacterial lactic acid fermentation - a review.
Reddy, Gopal; Altaf, Md; Naveena, B J; Venkateshwar, M; Kumar, E Vijay
2008-01-01
Lactic acid, an enigmatic chemical has wide applications in food, pharmaceutical, leather, textile industries and as chemical feed stock. Novel applications in synthesis of biodegradable plastics have increased the demand for lactic acid. Microbial fermentations are preferred over chemical synthesis of lactic acid due to various factors. Refined sugars, though costly, are the choice substrates for lactic acid production using Lactobacillus sps. Complex natural starchy raw materials used for production of lactic acid involve pretreatment by gelatinization and liquefaction followed by enzymatic saccharification to glucose and subsequent conversion of glucose to lactic acid by Lactobacillus fermentation. Direct conversion of starchy biomass to lactic acid by bacteria possessing both amylolytic and lactic acid producing character will eliminate the two step process to make it economical. Very few amylolytic lactic acid bacteria with high potential to produce lactic acid at high substrate concentrations are reported till date. In this view, a search has been made for various amylolytic LAB involved in production of lactic acid and utilization of cheaply available renewable agricultural starchy biomass. Lactobacillus amylophilus GV6 is an efficient and widely studied amylolytic lactic acid producing bacteria capable of utilizing inexpensive carbon and nitrogen substrates with high lactic acid production efficiency. This is the first review on amylolytic bacterial lactic acid fermentations till date.
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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.
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Rajan, Sujata Sundara; Turovskiy, Yevgeniy; Singh, Yashveer; Chikindas, Michael L.; Sinko, Patrick J.
2014-01-01
Women with bacterial vaginosis (BV) display reduced vaginal acidity, which make them susceptible to associated infections such as HIV. In the current study, poly(ethylene glycol) (PEG) nanocarrier-based degradable hydrogels were developed for the controlled release of lactic acid in the vagina of BV-infected women. PEG-lactic acid (PEG-LA) nanocarriers were prepared by covalently attaching lactic acid to 8-arm PEG-SH via cleavable thioester bonds. PEG-LA nanocarriers with 4 copies of lactic acid per molecule provided controlled release of lactic acid with a maximum release of 23% and 47% bound lactic acid in phosphate buffered saline (PBS, pH 7.4) and acetate buffer (AB, pH 4.3), respectively. The PEG nanocarrier-based hydrogels were formed by cross-linking the PEG-LA nanocarriers with 4-arm PEG-NHS via degradable thioester bonds. The nanocarrier-based hydrogels formed within 20 min under ambient conditions and exhibited an elastic modulus that was 100-fold higher than the viscous modulus. The nanocarrier-based degradable hydrogels provided controlled release of lactic acid for several hours; however, a maximum release of only 10%–14% bound lactic acid was observed possibly due to steric hindrance of the polymer chains in the cross-linked hydrogel. In contrast, hydrogels with passively entrapped lactic acid showed burst release with complete release within 30 min. Lactic acid showed antimicrobial activity against the primary BV pathogen Gardnerella vaginalis with a minimum inhibitory concentration (MIC) of 3.6 mg/ml. In addition, the hydrogels with passively entrapped lactic acid showed retained antimicrobial activity with complete inhibition G. vaginalis growth within 48 h. The results of the current study collectively demonstrate the potential of PEG nanocarrier-based hydrogels for vaginal administration of lactic acid for preventing and treating BV. PMID:25223229
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Overexpression of ESBP6 improves lactic acid resistance and production in Saccharomyces cerevisiae.
Sugiyama, Minetaka; Akase, Shin-Pei; Nakanishi, Ryota; Kaneko, Yoshinobu; Harashima, Satoshi
2016-10-01
Polylactic acid plastics are receiving increasing attention for the control of atmospheric CO2 emissions. Lactic acid, the building block for polylactic acid, is produced by fermentation technology from renewable carbon sources. The yeast Saccharomyces cerevisiae, harboring the lactate dehydrogenases gene (LDH), produces lactic acid at a large scale due to its strong acid resistance, to its simple nutritional requirements and to its ease of genetic engineering. Since improvement of lactic acid resistance is correlated with an increase of lactic acid production under non-neutralizing condition, we isolated a novel gene that enhances lactic acid resistance using a multi-copy yeast genomic DNA library. In this study, we identified the ESBP6 gene, which increases lactic acid resistance when overexpressed and which encodes a protein with similarity to monocarboxylate permeases. Although ESBP6 was not induced in response to lactic acid stress, it caused weak but reproducible sensitivity to lactic acid when disrupted. Furthermore, intracellular pH in the ESBP6 overexpressing strain was higher than that in the wild-type strain under lactic acid stressed condition, suggesting that Esbp6 plays some roles in lactic acid adaptation response. The ESBP6 overexpressing strain carrying the LDH gene induced 20% increase in lactic acid production compared with the wild-type strain carrying the LDH gene under non-neutralizing conditions. These results indicate that overexpression of ESBP6 provides a novel and useful tool to improve lactic acid resistance and lactic acid production in yeast. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
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Jian, Qiwei; Li, Xiang; Chen, Yinguang; Liu, Yanan; Pan, Yin
2016-10-01
It has been widely accepted that the most environmentally beneficial way to treat waste activated sludge (WAS), the byproduct of municipal wastewater treatment plant, is to recover the valuable organic acid. However, the bio-conversion of lactic acid, one of the high added-value chemical, is seldom reported from WAS fermentation. In this paper, l-lactic acid was observed dominant in the WAS fermentation liquid with carbohydrate addition at ambient temperature. Furthermore, the effect of temperature on l-lactic acid and d-lactic acid production was fully discussed: two isomers were rapidly produced and consumed up in one day at mesophilic condition; and almost optically pure l-lactic acid was generated at thermophilic condition, yet time-consuming with yield of l-lactic acid enhancing by 52.9% compared to that at ambient temperature. The study mechanism showed that mesophilic condition was optimal for both production and consumption of l-lactic acid and d-lactic acid, while consumption of l-lactic acid and production of d-lactic acid were severely inhibited at thermophilic condition. Therefore, by maintaining thermophilic for 4 h in advance and subsequently fermenting mesophilic for 34 h, the concentration of l-lactic acid with optical activity of 98.3% was improved to 16.6 ± 0.5 g COD/L at a high specific efficiency of 0.6097/d.
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Liu, Gang; Sun, Jiaoe; Zhang, Jian; Tu, Yi; Bao, Jie
2015-12-01
Technological potentials of l-lactic acid production from corn stover feedstock were investigated by experimental and techno-economic studies. An optimal performance with 104.5 g/L in l-lactic acid titer and 71.5% in overall yield from cellulose in corn stover to l-lactic acid using an engineered Pediococcus acidilactici strain were obtained by overcoming several technical barriers. A rigorous Aspen plus model for l-lactic acid production starting from dry dilute acid pretreated and biodetoxified corn stover was developed. The techno-economic analysis shows that the minimum l-lactic acid selling price (MLSP) was $0.523 per kg, which was close to that of the commercial l-lactic acid produced from starch feedstock, and 24% less expensive than that of ethanol from corn stover, even though the xylose utilization was not considered. The study provided a prototype of industrial application and an evaluation model for high titer l-lactic acid production from lignocellulose feedstock. Copyright © 2015 Elsevier Ltd. All rights reserved.
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D-Lactic acid biosynthesis from biomass-derived sugars via Lactobacillus delbrueckii fermentation.
Zhang, Yixing; Vadlani, Praveen V
2013-12-01
Poly-lactic acid (PLA) derived from renewable resources is considered to be a good substitute for petroleum-based plastics. The number of poly L-lactic acid applications is increased by the introduction of a stereocomplex PLA, which consists of both poly-L and D-lactic acid and has a higher melting temperature. To date, several studies have explored the production of L-lactic acid, but information on biosynthesis of D-lactic acid is limited. Pulp and corn stover are abundant, renewable lignocellulosic materials that can be hydrolyzed to sugars and used in biosynthesis of D-lactic acid. In our study, saccharification of pulp and corn stover was done by cellulase CTec2 and sugars generated from hydrolysis were converted to D-lactic acid by a homofermentative strain, L. delbrueckii, through a sequential hydrolysis and fermentation process (SHF) and a simultaneous saccharification and fermentation process (SSF). 36.3 g L(-1) of D-lactic acid with 99.8 % optical purity was obtained in the batch fermentation of pulp and attained highest yield and productivity of 0.83 g g(-1) and 1.01 g L(-1) h(-1), respectively. Luedeking-Piret model described the mixed growth-associated production of D-lactic acid with a maximum specific growth rate 0.2 h(-1) and product formation rate 0.026 h(-1), obtained for this strain. The efficient synthesis of D-lactic acid having high optical purity and melting point will lead to unique stereocomplex PLA with innovative applications in polymer industry.
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Lactic acid production from xylose by Geobacillus stearothermophilus strain 15
NASA Astrophysics Data System (ADS)
Kunasundari, B.; Naresh, S.; Chu, J. E.
2017-09-01
Lactic acid is an important compound with a wide range of industrial applications. The present study tested the efficiency of xylose, as a sole carbon source to be converted to lactic acid by Geobacillus stearothermophilus strain 15. To the best of our knowledge, limited information is available on the directed fermentation of xylose to lactic acid by this bacterium. The effects of different parameters such as temperature, pH, incubation time, agitation speed, concentrations of nitrogen and carbon sources on the lactic acid production were investigated statistically. It was found that the bacterium exhibited poor assimilation of xylose to lactic acid. Temperature, agitation rate and incubation time were determined to improve the lactic acid production slightly. The highest lactic acid yield obtained was 8.9% at 45°C, 300 RPM, 96 h, pH of 6.0 with carbon and nitrogen source concentrations were fixed at 5% w/v.
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Corrosion Behavior of Titanium in Artificial Saliva by Lactic Acid
Qu, Qing; Wang, Lei; Chen, Yajun; Li, Lei; He, Yue; Ding, Zhongtao
2014-01-01
As one of the main products produced by oral microorganisms, the role of lactic acid in the corrosion of titanium is very important. In this study, the corrosion behavior of titanium in artificial saliva with and without lactic acid were investigated by open-circuit potentials (OCPs), polarization curves and electrochemical impedance spectroscopy (EIS). OCP firstly increased with the amount of lactic acid from 0 to 3.2 g/L and then tended to decrease from 3.2 to 5.0 g/L. The corrosion of titanium was distinctly affected by lactic acid, and the corrosion rate increased with increasing the amount of lactic acid. At each concentration of lactic acid, the corrosion rate clearly increased with increasing the immersing time. Results of scanning electron microscopy (SEM) also indicated that lactic acid accelerated the pitting corrosion in artificial saliva. A probable mechanism was also proposed to explain the experimental results. PMID:28788143
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Xu, Qianqian; Zang, Ying; Zhou, Jie; Liu, Peng; Li, Xin; Yong, Qiang; Ouyang, Jia
2016-11-01
Inulin is a readily available feedstock for cost-effective production of biochemicals. To date, several studies have explored the production of bioethanol, high-fructose syrup and fructooligosaccharide, but there are no studies regarding the production of D-lactic acid using inulin as a carbon source. In the present study, chicory-derived inulin was used for D-lactic acid biosynthesis by Lactobacillus bulgaricus CGMCC 1.6970. Compared with separate hydrolysis and fermentation processes, simultaneous saccharification and fermentation (SSF) has demonstrated the best performance of D-lactic acid production. Because it prevents fructose inhibition and promotes the complete hydrolysis of inulin, the highest D-lactic acid concentration (123.6 ± 0.9 g/L) with a yield of 97.9 % was obtained from 120 g/L inulin by SSF. Moreover, SSF by L. bulgaricus CGMCC 1.6970 offered another distinct advantage with respect to the higher optical purity of D-lactic acid (>99.9 %) and reduced number of residual sugars. The excellent performance of D-lactic acid production from inulin by SSF represents a high-yield method for D-lactic acid production from non-food grains.
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USDA-ARS?s Scientific Manuscript database
Production of lactic acid from renewable sugars has received growing attention as lactic acid can be used for making renewable and bio-based plastics. However, most prior studies have focused on production of lactic acid from glucose despite cellulosic hydrolysates contain xylose as well as glucose....
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Catalytic conversion of lactic acid and its derivatives
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kokitkar, P.B.; Langford, R.; Miller, D.J.
1993-12-31
The catalytic upgrading of lactic acid and methyl lactate is being investigated. With the commercialization of inexpensive starch fermentation technologies, US production of lactic acid is undergoing a surge. Dropping cost and increased availability offer a major opportunity to develop lactic acid as a renewable feedstock for chemicals production. IT can be catalytically converted into several important chemical intermediates currently derived from petroleum including acrylic acid, propanoic acid, and 2,3-pentanedione. The process can expand the potential of biomass as a substitute feedstock for petroleum and can benefit both the US chemical process industry and US agriculture via increased production ofmore » high-value, non-food products from crops and crop byproducts. Reaction studies of lactic acid and its ester are conducted in fixed bed reactors at 250-380{degrees}C and 0.1-0.5 MPa (1-5 atm) using salt catalysts on low surface area supports. Highest selectivities achieved are 42% to acrylic acid and 55% to 2,3-pentanedione from lactic acid over NaNO{sub 3} catalyst on low surface area silica support. High surface area (microporous) or highly acidic supports promote fragmentation to acetaldehyde and thus reduce yields of desirable products. The support acidity gives rice to lactic acid from neat methyl lactate feed but the lactic acid yield goes down after the nitrate salt is impregnated on the support. Both lactic acid and methyl lactate form 2,3-pentanedione. Methyl lactate reactions are more complex since it forms all the products obtained from lactic acid as well as many corresponding esters of the acids obtained from lactic acid (mainly methyl acrylate, methyl propionate, methyl acetate). At high temperatures, methyl acetate and acetic acid yields become significant from methyl lactate whereas lactic acid gives significant amount of acetol at high temperatures.« less
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Behaviors of D- and L-lactic acids during the brewing process of sake (Japanese rice wine).
Kodama, Shuji; Yamamoto, Atsushi; Matsunaga, Akinobu; Matsui, Keizou; Nakagomi, Kazuya; Hayakawa, Kazuichi
2002-02-13
The amounts of D- and L-lactic acids during the brewing process of sake were determined by capillary electrophoresis using 2-hydroxypropyl-beta-cyclodextrin as a chiral selector. Because L-lactic acid, which prevents the growth of nonuseful microorganisms, is a raw material of sake, the ratio of L-lactic acid to total lactic acid is almost 1.0 at the initial stage of sake brewing. During brewing, the ratio decreased gradually and finally reached 0.39. Yeast (Saccharomyces cerevisiae) for sake brewing produced D-lactic acid, but not L-lactic acid in a culture medium. These results suggest that the decrease in the ratio of L-lactic acid to total lactic acid during sake brewing resulted in D-lactic acid production by yeast. The ratios in 18 brands of sake obtained commercially ranged from 0.23 to 0.78. The levels of D-lactic acid in sake (140-274 mg/L) were in a narrower range than those of L-lactic acid (61-461 mg/L). Although the D-lactic acid level in sake did not correspond to total lactic acid level, the L-lactic acid level correlated well with total lactic acid level (R(2) = 0.867). These results suggest that the ratio of L-lactic acid to total lactic acid in sake reflected the amount of L-lactic acid added at the initial stage of sake brewing.
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Biotechnological production of enantiomerically pure d-lactic acid.
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.
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The behavior and importance of lactic acid complexation in Talspeak extraction systems
DOE Office of Scientific and Technical Information (OSTI.GOV)
Grimes, Travis S.; Nilsson, Mikael; Nash, Kenneth L.
2008-07-01
Advanced partitioning of spent nuclear fuel in the UREX +la process relies on the TALSPEAK process for separation of fission-product lanthanides from trivalent actinides. The classic TALSPEAK utilizes an aqueous medium of both lactic acid and diethylenetriaminepentaacetic acid and the extraction reagent di(2-ethylhexyl)phosphoric acid in an aromatic diluent. In this study, the specific role of lactic acid and the complexes involved in the extraction of the trivalent actinides and lanthanides have been investigated using {sup 14}C-labeled lactic acid. Our results show that lactic acid partitions between the phases in a complex fashion. (authors)
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Cerebrospinal fluid in tuberculous meningitis exhibits only the L-enantiomer of lactic acid.
Mason, Shayne; Reinecke, Carolus J; Kulik, Willem; van Cruchten, Arno; Solomons, Regan; van Furth, A Marceline Tutu
2016-06-07
The defining feature of the cerebrospinal fluid (CSF) collected from infants and children with tuberculous meningitis (TBM), derived from an earlier untargeted nuclear magnetic resonance (NMR) metabolomics study, was highly elevated lactic acid. Undetermined was the contribution from host response (L-lactic acid) or of microbial origin (D-lactic acid), which was set out to be determined in this study. In this follow-up study, we used targeted ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) to determine the ratio of the L and D enantiomers of lactic acid in these CSF samples. Here we report for the first time that the lactic acid observed in the CSF of confirmed TBM cases was in the L-form and solely a response from the host to the infection, with no contribution from any bacteria. The significance of elevated lactic acid in TBM appears to be that it is a crucial energy substrate, used preferentially over glucose by microglia, and exhibits neuroprotective capabilities. These results provide experimental evidence to support our conceptual astrocyte-microglia lactate shuttle model formulated from our previous NMR-based metabolomics study - highlighting the fact that lactic acid plays an important role in neuroinflammatory diseases such as TBM. Furthermore, this study reinforces our belief that the determination of enantiomers of metabolites corresponding to infectious diseases is of critical importance in substantiating the clinical significance of disease markers.
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Ramirez-Hernandez, Alejandra; Brashears, Mindy M; Sanchez-Plata, Marcos X
2018-01-01
The poultry processing industry has been undergoing a series of changes as it modifies processing practices to comply with new performance standards for chicken parts and comminuted poultry products. The regulatory approach encourages the use of intervention strategies to prevent and control foodborne pathogens in poultry products and thus improve food safety and protect human health. The present studies were conducted to evaluate the efficacy of antimicrobial interventions for reducing Salmonella on inoculated chicken parts under simulated commercial processing conditions. Chicken pieces were inoculated by immersion in a five-strain Salmonella cocktail at 6 log CFU/mL and then treated with organic acids and oxidizing agents on a commercial rinsing conveyor belt. The efficacy of spraying with six different treatments (sterile water, lactic acid, acetic acid, buffered lactic acid, acetic acid in combination with lactic acid, and peracetic acid) at two concentrations was evaluated on skin-on and skin-off chicken thighs at three application temperatures. Skinless chicken breasts were used to evaluate the antimicrobial efficacy of lactic acid and peracetic acid. The color stability of treated and untreated chicken parts was assessed after the acid interventions. The lactic acid and buffered lactic acid treatments produced the greatest reductions in Salmonella counts. Significant differences between the control and water treatments were identified for 5.11% lactic acid and 5.85% buffered lactic acid in both skin-on and skin-off chicken thighs. No significant effect of treatment temperature for skin-on chicken thighs was found. Lactic acid and peracetic acid were effective agents for eluting Salmonella cells attached to chicken breasts.
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Effects of intraaortic balloon augmentation in a porcine model of endotoxemic shock.
Engoren, Milo; Habib, Robert H
2004-03-01
Patients with septic shock commonly have myocardial dysfunction associated with lactic acid production and troponin I release. The purpose of this study was to evaluate the effects on intraaortic balloon pump (IABP) support on myocardial dysfunction. Prospective, randomized controlled study. Animal research laboratory. Ten pigs had arterial, pulmonary arterial, and coronary catheters inserted. After receiving endotoxin infusion over 30 min, half the animals received IABP support. Coronary sinus lactic acid levels (P< 0.05 for both 90 min versus baseline and 60 min versus baseline) and arterial lactic acid levels (P < 0.05 for both 90 min versus baseline and 60 min versus baseline) increased with time but did not differ between IABP and sham groups. While overall there was no difference with time in myocardial lactic acid consumption or production (calculated as arterial lactic acid level minus coronary sinus lactic acid level), the IABP group showed net myocardial lactic acid consumption at 90 min, while the sham group showed myocardial lactic acid production. Three of five animals in each group showed troponin I release. The levels were similar and did not differ between groups. IABP had no benefits in this porcine model of endotoxemic shock.
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Graves, Tara; Narendranath, Neelakantam V; Dawson, Karl; Power, Ronan
2007-01-01
The combined effects of lactic acid and acetic acid on ethanol production by S. cerevisiae in corn mash, as influenced by temperature, were examined. Duplicate full factorial experiments (three lactic acid concentrations x three acetic acid concentrations) were performed to evaluate the interaction between lactic and acetic acids on the ethanol production of yeast at each of the three temperatures, 30, 34, and 37 degrees C. Corn mash at 30% dry solids adjusted to pH 4 after lactic and acetic acid addition was used as the substrate. Ethanol production rates and final ethanol concentrations decreased (P<0.001) progressively as the concentration of combined lactic and acetic acids in the corn mash increased and the temperature was raised from 30 to 37 degrees C. At 30 degrees C, essentially no ethanol was produced after 96 h when 0.5% w/v acetic acid was present in the mash (with 0.5, 2, and 4% w/v lactic acid). At 34 and 37 degrees C, the final concentrations of ethanol produced by the yeast were noticeably reduced by the presence of 0.3% w/v acetic acid and >or=2% w/v lactic acid. It can be concluded that, as in previous studies with defined media, lactic acid and acetic acid act synergistically to reduce ethanol production by yeast in corn mash. In addition, the inhibitory effects of combined lactic and acetic acid in corn mash were more apparent at elevated temperatures.
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Gao, Chao; Qiu, Jianhua; Li, Jingchen; Ma, Cuiqing; Tang, Hongzhi; Xu, Ping
2009-03-01
D-lactic acid and pyruvic acid are two important building block intermediates. Production of D-lactic acid and pyruvic acid from racemic lactic acid by biotransformation is economically interesting. Biocatalyst prepared from 9 g dry cell wt l(-1) of Pseudomonas stutzeri SDM could catalyze 45.00 g l(-1)DL-lactic acid into 25.23 g l(-1)D-lactic acid and 19.70 g l(-1) pyruvic acid in 10h. Using a simple ion exchange process, D-lactic acid and pyruvic acid were effectively separated from the biotransformation system. Co-production of d-lactic acid and pyruvic acid by enantioselective oxidation of racemic lactic acid is technically feasible.
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Berlowska, Joanna; Cieciura, Weronika; Borowski, Sebastian; Dudkiewicz, Marta; Binczarski, Michal; Witonska, Izabela; Otlewska, Anna; Kregiel, Dorota
2016-10-17
Research into fermentative production of lactic acid from agricultural by-products has recently concentrated on the direct conversion of biomass, whereby pure sugars are replaced with inexpensive feedstock in the process of lactic acid production. In our studies, for the first time, the source of carbon used is sugar beet pulp, generated as a by-product of industrial sugar production. In this paper, we focus on the simultaneous saccharification of lignocellulosic biomass and fermentation of lactic acid, using mixed cultures with complementary assimilation profiles. Lactic acid is one of the primary platform chemicals, and can be used to synthesize a wide variety of useful products, including green propylene glycol. A series of controlled batch fermentations was conducted under various conditions, including pretreatment with enzymatic hydrolysis. Inoculation was performed in two sequential stages, to avoid carbon catabolite repression. Biologically-synthesized lactic acid was catalytically reduced to propylene glycol over 5% Ru/C. The highest lactic acid yield was obtained with mixed cultures. The yield of propylene glycol from the biological lactic acid was similar to that obtained with a water solution of pure lactic acid. Our results show that simultaneous saccharification and fermentation enables generation of lactic acid, suitable for further chemical transformations, from agricultural residues.
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The Promotion of Erythropoiesis via the Regulation of Reactive Oxygen Species by Lactic Acid
Luo, Shun-Tao; Zhang, Dong-Mei; Qin, Qing; Lu, Lian; Luo, Min; Guo, Fu-Chun; Shi, Hua-Shan; Jiang, Li; Shao, Bin; Li, Meng; Yang, Han-Shuo; Wei, Yu-Quan
2017-01-01
The simultaneous increases in blood lactic acid and erythrocytes after intense exercise could suggest a link between lactate and the erythropoiesis. However, the effects of lactic acid on erythropoiesis remain to be elucidated. Here, we utilized a mouse model to determine the role of lactic acid in this process in parallel with studies using leukaemic K562 cells. Treatment of K562 cells in vitro with lactic acid increased the mRNA and protein expression of haemoglobin genes and the frequency of GPA+ cells. Also, increases in haematocrit and CD71−/Ter119+ erythroid cells were observed in lactic acid-treated mice, which showed a physiological increase in blood lactate. Mouse bone marrow CD34+/CD117− cells showed an increase in erythroid burst-forming units after stimulation with lactic acid in vitro. Furthermore, lactic acid increased the intracellular reactive oxygen species (ROS) content in bone marrow and in K562 cells. Erythroid differentiation induced in Haematopoietic Stem Cells (HSCs) and K562 cells by lactic acid was abolished by reducing ROS levels with SOD or 2-mercaptoethanol, which suggests that ROS is a critical regulator of this process. These findings provide a better understanding of the role of lactic acid in cellular metabolism and physiological functions. PMID:28165036
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Bernier, Ulrich R; Kline, Daniel L; Allan, Sandra A; Barnard, Donald R
2015-03-01
The attraction of female Aedes aegypti to single compounds and binary compositions containing L-lactic acid and an additional saturated compound from a set of ketones, sulfides, and chloroalkanes was studied using a triple-cage dual-port olfactometer. These chemical classes were studied because of their structural relation to acetone, dimethyl disulfide, and dichloromethane, which have all been reported to synergize attraction to L-lactic acid. Human odors, carbon dioxide, and the binary mixture of L-lactic acid and CO₂served as controls for comparison of attraction responses produced by the binary mixtures. All tested mixtures that contained chloroalkanes attracted mosquitoes at synergistic levels, as did L-lactic acid and CO₂. Synergism was less frequent in mixtures of L-lactic acid with sulfides and ketones; in the case of ketones, synergistic attraction was observed only for L-lactic acid combined with acetone or butanone. Suppression or inhibition of attraction response was observed for combinations that contained ketones of C7-C12 molecular chain length (optimum in the C8-C10 range). This inhibition effect is similar to that observed previously for specific ranges of carboxylic acids, aldehydes, and alcohols.
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Melo, Nadiele T M; Mulder, Kelly C L; Nicola, André Moraes; Carvalho, Lucas S; Menino, Gisele S; Mulinari, Eduardo; Parachin, Nádia S
2018-02-16
Lactic acid is the monomer unit of the bioplastic poly-lactic acid (PLA). One candidate organism for lactic acid production is Pichia pastoris , a yeast widely used for heterologous protein production. Nevertheless, this yeast has a poor fermentative capability that can be modulated by controlling oxygen levels. In a previous study, lactate dehydrogenase (LDH) activity was introduced into P. pastoris, enabling this yeast to produce lactic acid. The present study aimed to increase the flow of pyruvate towards the production of lactic acid in P. pastoris . To this end, a strain designated GLp was constructed by inserting the bovine lactic acid dehydrogenase gene (LDHb) concomitantly with the interruption of the gene encoding pyruvate decarboxylase (PDC). Aerobic fermentation, followed by micro-aerophilic culture two-phase fermentations, showed that the GLp strain achieved a lactic acid yield of 0.65 g/g. The distribution of fermentation products demonstrated that the acetate titer was reduced by 20% in the GLp strain with a concomitant increase in arabitol production: arabitol increased from 0.025 g/g to 0.174 g/g when compared to the GS115 strain. Taken together, the results show a significant potential for P. pastoris in producing lactic acid. Moreover, for the first time, physiological data regarding co-product formation have indicated the redox balance limitations of this yeast.
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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.
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Lampe, Kyle J.; Namba, Rachael M.; Silverman, Tyler R.; Bjugstad, Kimberly B.
2009-01-01
Biomaterials prepared from polyesters of lactic acid and glycolic acid, or a mixture of the two, degrade in the presence of water into the naturally occurring metabolites, lactic acid and glycolic acid. While the lactic acid degradation product that is released from biomaterials is well-tolerated by the body, lactic acid can influence the metabolic function of cells; it can serve as an energy substrate for cells, and has been shown to have antioxidant properties. Neural precursor cells, a cell population of considerable interest as a source of cells for neural tissue regeneration strategies, generate a high amount of reactive oxygen species, and when associated with a degradable biomaterial, may be impacted by released lactic acid. In this work, the effect of lactic acid on a neural cell population containing proliferative neural precursor cells was examined in monolayer culture. Lactic acid was found to scavenge exogenously added free radicals produced in the presence of either hydrogen peroxide or a photoinitiator (I2959) commonly utilized in the preparation of photopolymerizable biomaterials. In addition to its effect on exogenously added free radicals, lactic acid reduced intracellular redox state, increased the proliferation of the cell population, and modified the cell composition. The findings of this study provide insight into the role that lactic acid plays naturally on developing neural cells and are also of interest to biomaterials scientists that are focused on the development of degradable lactic-acid based polymers for cell culture devices. The effect of lactic acid on other cell populations may differ and should be characterized to best understand how cells function in degradable cell culture devices. PMID:19408314
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Wang, Fang; Liu, Xiuxiu; Yuan, Jian; Yang, Siqian; Li, Yueqin; Gao, Qinwei
2016-10-01
Poly(lactic-co-glycolic) acid (PLGA) is synthesized via melt polycondensation directly from lactic acid and glycolic acid with a feed molar ratio of 75/25. Bovine serum albumin, which is used as model protein, is entrapped into the poly(lactic-co-glycolic acid) microspheres with particle size of 260.9 ± 20.0 nm by the double emulsification method. Then it is the first report of producing more carboxyl groups by poly(lactic-co-glycolic acid) surface hydrolysis. The purpose is developing poly(lactic-co-glycolic acid) microspheres surface, which is modified with chitosan by chemical reaction between carboxyl groups and amine groups. The particle size and the positive zeta potential of the poly(lactic-co-glycolic acid)/chitosan microspheres are 388.2 ± 35.6 nm and 10.4 ± 2.9 mV, respectively. The drug loading ratio and encapsulation efficacy of poly(lactic-co-glycolic acid)/chitosan microspheres are 36.3% and 57.5%, which are higher than PLGA microspheres. Furthermore, the drug burst release of poly(lactic-co-glycolic acid)/chitosan microspheres at 10 h is decreased to 21.72% while the corresponding value of the poly(lactic-co-glycolic acid) microsphere is 64.56%. These results reveal that surface hydrolysis modification of poly(lactic-co-glycolic acid) is an efficient method to improve the negative potential and chemical reaction properties of the polymer. And furthermore, this study shows that chitosan-modified poly(lactic-co-glycolic acid) microspheres is a promising system for the controlled release of pharmaceutical proteins. © The Author(s) 2016.
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Bai, Zhongzhong; Gao, Zhen; Sun, Junfei; Wu, Bin; He, Bingfang
2016-05-01
d-Lactic acid, is an important organic acid produced from agro-industrial wastes by Sporolactobacillus inulinus YBS1-5 was investigated to reduce the raw material cost of fermentation. The YBS1-5 strain could produce d-lactic acid by using cottonseed meal as the sole nitrogen source. For efficient utilization, the cottonseed meal was enzymatically hydrolyzed and simultaneously utilized during d-lactic acid fermentation. Corncob residues are rich in cellulose and can be enzymatically hydrolyzed without pretreatment. The hydrolysate of this lignocellulosic waste could be utilized by strain YBS1-5 as a carbon source for d-lactic acid production. Under optimal conditions, a high d-lactic acid concentration (107.2g/L) was obtained in 7-L fed-batch fermenter, with an average productivity of 1.19g/L/h and a yield of 0.85g/g glucose. The optical purity of d-lactic acid in the broth was 99.2%. This study presented a new approach for low-cost production of d-lactic acid for an industrial application. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Inoue, Yoshito; Shinka, Toshihiro; Ohse, Morimasa; Kohno, Miyuki; Konuma, Kunio; Ikawa, Hiromichi; Kuhara, Tomiko
2007-08-01
The present study showed that the D-lactic acid configuration ratio in the urine rose earlier than that in blood or the urinary or blood D-lactic acid levels upon disease onset, and that the D-lactic acid measurement in urine is more sensitive and useful than that in blood. As this result, a prediction of a D-lactic acidosis may be possible. To simplify the procedure for detecting D-lactic acid, we first showed a correlation between the D-lactic acid configuration ratio in urine and blood, indicating urine could be used. To separate the optical isomers of lactic acid, we simplified our previous procedure. For chiral recognition, we chose O-acetyl-(-)-menthylation and analyzed the samples under GC/MS by capillary gas chromatography on a DB-5 MS column. This procedure is less sensitive than the former method, but it is faster and simpler, requiring only one derivatization step. This method may be useful for predicting D-lactic acidosis in patients with short bowel syndrome.
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Identification and Assessment of the Behavior of Methicillin-Resistant Staphylococci in Cheese.
Steinka, Izabela
2018-03-22
This study was carried out with the aim of identifying and assessing methicillin-resistant Staphylococcus aureus (MRSA) during lactic acid cheese storage. The study involved 30 assortments of lactic acid cheese and 21 cheeses with S. aureus TWP11616 (MRSA). Results showed low MRSA contamination levels in lactic acid cheese. The majority of cow and goat lactic acid cheese samples (more than 72%) were characterized by a low level of MRSA (≤10 CFU/g). With regard to cow and sheep lactic acid cheese, methicillin-resistant Staphylococcus spp. contamination levels of ≥100 CFU/g were found in 88 and 100% of samples, respectively. The microbial dynamics of MRSA changes in lactic acid cheese suggest a significant reduction in contamination levels after 4 days of product storage, and this decrease is likely not dependent on the type of packaging method.
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Leung, Yat H; Belanger, Francois; Lu, Jennifer; Turgeon, Jacques; Michaud, Veronique
2017-01-01
Drug-induced myopathy is a serious side effect that often requires removal of a medication from a drug regimen. For most drugs, the underlying mechanism of drug-induced myopathy remains unclear. Monocarboxylate transporters (MCTs) mediate L-lactic acid transport, and inhibition of MCTs may potentially lead to perturbation of L-lactic acid accumulation and muscular disorders. Therefore, we hypothesized that L-lactic acid transport may be involved in the development of drug-induced myopathy. The aim of this study was to assess the inhibitory potential of 24 acidic drugs on L-lactic acid transport using breast cancer cell lines Hs578T and MDA-MB-231, which selectively express MCT1 and MCT4, respectively. The influx transport of L-lactic acid was minimally inhibited by all drugs tested. The efflux transport was next examined: loratadine (IC50: 10 and 61 µM) and atorvastatin (IC50: 78 and 41 µM) demonstrated the greatest potency for inhibition of L-lactic acid efflux by MCT1 and MCT4, respectively. Acidic drugs including fluvastatin, cerivastatin, simvastatin acid, lovastatin acid, irbesartan and losartan exhibited weak inhibitory potency on L-lactic acid efflux. Our results suggest that some acidic drugs, such as loratadine and atorvastatin, can inhibit the efflux transport of L-lactic acid. This inhibition may cause an accumulation of intracellular L-lactic acid leading to acidification and muscular disorders. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.
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Catalytical Conversion of Carbohydrates into Lactic Acid via Hydrothermal Reaction
NASA Astrophysics Data System (ADS)
Wei, Zhen; Jin, Fangming; Zhang, Guangyi; Zhang, Shiping; Yao, Guodong
2010-11-01
This paper focuses on catalytical conversion of carbohydrates into lactic acid, under the hydrothermal conditions, which may have a promising future for its high speediness and effectiveness. The catalysis of ZnO was investigated to improve the lactic acid yields. The results showed that the lactic acid yields increased immensely by the addition of ZnO. The effects of the reaction time and the addition amount of ZnO on the conversion of carbohydrates to lactic acid were studied. The highest lactic acid yields reached up to 28% starting from glucose after the reaction time of 60 s under the conditions of 0.2 mmol ZnO, 300° C, the filling rate of 35%, and over 30% starting from fructose at the same temperature and filling rate when the reaction time of 40 s and 2.0 mmol ZnO were employed. The collaborative effects of ZnO and NaOH used as the catalysts together at the same time were also studied. Furthermore, the catalytic mechanism of ZnO in the hydrothermal conversion of carbohydrates into lactic acid was discussed.
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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.
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NASA Astrophysics Data System (ADS)
Li, Yebo; Shahbazi, Abolghasem; Williams, Karen; Wan, Caixia
The processes of lactic acid production include two key stages, which are (a) fermentation and (b) product recovery. In this study, free cell of Bifidobacterium longum was used to produce lactic acid from cheese whey. The produced lactic acid was then separated and purified from the fermentation broth using combination of nanofiltration and reverse osmosis membranes. Nanofiltration membrane with a molecular weight cutoff of 100-400 Da was used to separate lactic acid from lactose and cells in the cheese whey fermentation broth in the first step. The obtained permeate from the above nanofiltration is mainly composed of lactic acid and water, which was then concentrated with a reverse osmosis membrane in the second step. Among the tested nanofiltration membranes, HL membrane from GE Osmonics has the highest lactose retention (97±1%). In the reverse osmosis process, the ADF membrane could retain 100% of lactic acid to obtain permeate with water only. The effect of membrane and pressure on permeate flux and retention of lactose/lactic acid was also reported in this paper.
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Ma, Kedong; Maeda, Toshinari; You, Huiyan; Shirai, Yoshihito
2014-01-01
The development of a low-cost polymer-grade L-lactic acid production process was achieved in this study. Excess sludge hydrolyzate (ESH) was chosen as nutrient source for the objective of reducing nutrient cost in lactic acid production. 1% of ESH had high performance in lactic acid production relative to 2g/l yeast extract (YE) while the production cost of ESH was much lower than that of YE, indicating ESH was a promising substitute of YE. By employing a thermophilic strain of Bacillus coagulans (NBRC 12583), non-sterilized batch and repeated batch L-lactic acid fermentation was successfully performed, and the optical purity of L-lactic acid accumulated was more than 99%. Moreover, the factors associated with cell growth and lactic acid fermentation was investigated through a two-stage lactic acid production strategy. Oxygen played an important role in cell growth, and the optimal condition for cell growth and fermentation was pH 7.0 and 50°C. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Sirisan, V; Pattarajinda, V; Vichitphan, K; Leesing, R
2013-08-01
Ruminal organic acid production, especially lactic acid, can be modified by feeding cattle highly concentrated diets, which have been shown to adversely affect dairy cattle health. Therefore, the use of lactic acid-utilizing organisms is considered to be a potential method for controlling lactic acid levels. This study was conducted to isolate and identify lactic acid-utilizing yeasts from the ruminal fluid of dairy cattle and to determine the specific growth rate and generation time when using lactic acid as a carbon source instead of glucose. Seventeen yeast isolates were examined in this study. Yeasts isolated from dairy cattle that were fed a high cassava pulp diet (HCP) had higher specific growth rates and shorter generation times than yeasts isolated from dairy cattle that were fed a high-concentrate diet (HC) and a mixed diet (M). The three most effective yeasts in terms of specific growth rate and generation time were Pichia kudriavzevii, Candida rugosa and Kodamaea ohmeri, with 99, 100 and 99% nucleotide identities, respectively. These three isolates could be used as potential probiotics in dairy cattle diets. This study demonstrates that yeasts isolated from the ruminal fluid of dairy cattle can utilize lactic acid as a carbon and energy source for growth. The isolated yeasts can be used as probiotic supplements for dairy cattle that are fed highly concentrated diets to reduce ruminal lactic acid production. © 2013 The Society for Applied Microbiology.
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Transcriptional Response to Lactic Acid Stress in the Hybrid Yeast Zygosaccharomyces parabailii
2017-01-01
ABSTRACT Lactic acid has a wide range of applications starting from its undissociated form, and its production using cell factories requires stress-tolerant microbial hosts. The interspecies hybrid yeast Zygosaccharomyces parabailii has great potential to be exploited as a novel host for lactic acid production, due to high organic acid tolerance at low pH and a fermentative metabolism with a high growth rate. Here we used mRNA sequencing (RNA-seq) to analyze Z. parabailii's transcriptional response to lactic acid added exogenously, and we explore the biological mechanisms involved in tolerance. Z. parabailii contains two homeologous copies of most genes. Under lactic acid stress, the two genes in each homeolog pair tend to diverge in expression to a significantly greater extent than under control conditions, indicating that stress tolerance is facilitated by interactions between the two gene sets in the hybrid. Lactic acid induces downregulation of genes related to cell wall and plasma membrane functions, possibly altering the rate of diffusion of lactic acid into cells. Genes related to iron transport and redox processes were upregulated, suggesting an important role for respiratory functions and oxidative stress defense. We found differences in the expression profiles of genes putatively regulated by Haa1 and Aft1/Aft2, previously described as lactic acid responsive in Saccharomyces cerevisiae. Furthermore, formate dehydrogenase (FDH) genes form a lactic acid-responsive gene family that has been specifically amplified in Z. parabailii in comparison to other closely related species. Our study provides a useful starting point for the engineering of Z. parabailii as a host for lactic acid production. IMPORTANCE Hybrid yeasts are important in biotechnology because of their tolerance to harsh industrial conditions. The molecular mechanisms of tolerance can be studied by analyzing differential gene expression under conditions of interest and relating gene expression patterns to protein functions. However, hybrid organisms present a challenge to the standard use of mRNA sequencing (RNA-seq) to study transcriptional responses to stress, because their genomes contain two similar copies of almost every gene. Here we used stringent mapping methods and a high-quality genome sequence to study the transcriptional response to lactic acid stress in Zygosaccharomyces parabailii ATCC 60483, a natural interspecies hybrid yeast that contains two complete subgenomes that are approximately 7% divergent in sequence. Beyond the insights we gained into lactic acid tolerance in this study, the methods we developed will be broadly applicable to other yeast hybrid strains. PMID:29269498
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Transcriptional Response to Lactic Acid Stress in the Hybrid Yeast Zygosaccharomyces parabailii.
Ortiz-Merino, Raúl A; Kuanyshev, Nurzhan; Byrne, Kevin P; Varela, Javier A; Morrissey, John P; Porro, Danilo; Wolfe, Kenneth H; Branduardi, Paola
2018-03-01
Lactic acid has a wide range of applications starting from its undissociated form, and its production using cell factories requires stress-tolerant microbial hosts. The interspecies hybrid yeast Zygosaccharomyces parabailii has great potential to be exploited as a novel host for lactic acid production, due to high organic acid tolerance at low pH and a fermentative metabolism with a high growth rate. Here we used mRNA sequencing (RNA-seq) to analyze Z. parabailii 's transcriptional response to lactic acid added exogenously, and we explore the biological mechanisms involved in tolerance. Z. parabailii contains two homeologous copies of most genes. Under lactic acid stress, the two genes in each homeolog pair tend to diverge in expression to a significantly greater extent than under control conditions, indicating that stress tolerance is facilitated by interactions between the two gene sets in the hybrid. Lactic acid induces downregulation of genes related to cell wall and plasma membrane functions, possibly altering the rate of diffusion of lactic acid into cells. Genes related to iron transport and redox processes were upregulated, suggesting an important role for respiratory functions and oxidative stress defense. We found differences in the expression profiles of genes putatively regulated by Haa1 and Aft1/Aft2, previously described as lactic acid responsive in Saccharomyces cerevisiae Furthermore, formate dehydrogenase ( FDH ) genes form a lactic acid-responsive gene family that has been specifically amplified in Z. parabailii in comparison to other closely related species. Our study provides a useful starting point for the engineering of Z. parabailii as a host for lactic acid production. IMPORTANCE Hybrid yeasts are important in biotechnology because of their tolerance to harsh industrial conditions. The molecular mechanisms of tolerance can be studied by analyzing differential gene expression under conditions of interest and relating gene expression patterns to protein functions. However, hybrid organisms present a challenge to the standard use of mRNA sequencing (RNA-seq) to study transcriptional responses to stress, because their genomes contain two similar copies of almost every gene. Here we used stringent mapping methods and a high-quality genome sequence to study the transcriptional response to lactic acid stress in Zygosaccharomyces parabailii ATCC 60483, a natural interspecies hybrid yeast that contains two complete subgenomes that are approximately 7% divergent in sequence. Beyond the insights we gained into lactic acid tolerance in this study, the methods we developed will be broadly applicable to other yeast hybrid strains. Copyright © 2018 Ortiz-Merino et al.
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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.
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Kobayashi, Masaki; Fujita, Itaru; Itagaki, Shirou; Hirano, Takeshi; Iseki, Ken
2005-07-01
Monocarboxylate transporter (MCT), which cotransport L-lactic acid and protons across cell membranes, are important for regulation of muscle pH. However, it has not been demonstrated in detail whether MCT isoform contribute to the transport of L-lactic acid in skeletal muscle. The aim of this study was to characterize L-lactic acid transport using an human rhabdomyosarcoma (RD) cell line as a model of human skeletal muscle. mRNAs of MCT 1, 2 and 4 were found to be expressed in RD cells. The [14C] L-lactic acid uptake was concentration-dependent with a Km of 1.19 mM. This Km value was comparable to its Km values for MCT1 or MCT2. MCT1 mRNA was found to be present markedly greater than that MCT2. Therefore, MCT1 most probably acts on L-lactic acid uptake at RD cells. [14C] L-Lactic acid efflux in RD cells was inhibited by alpha-cyano-4-hydroxycinnamate (CHC) but not by butyric acid, a substrate of MCT1. Accordingly, MCT2 or MCT4 is responsible for L-lactic acid efflux by RD cells. MCT4 mRNA was found to be present significantly greater than that MCT2. We conclude that MCT1 is responsible for L-lactic acid uptake and L-lactic acid efflux is mediated by MCT4 in RD cells.
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Production of lactic acid using a new homofermentative Enterococcus faecalis isolate
Subramanian, Mohan Raj; Talluri, Suvarna; Christopher, Lew P
2015-01-01
Lactic acid is an intermediate-volume specialty chemical for a wide range of food and industrial applications such as pharmaceuticals, cosmetics and chemical syntheses. Although lactic acid production has been well documented, improved production parameters that lead to reduced production costs are always of interest in industrial developments. In this study, we describe the production of lactic acid at high concentration, yield and volumetric productivity utilizing a novel homofermentative, facultative anaerobe Enterococcus faecalis CBRD01. The highest concentration of 182 g lactic acid l−1 was achieved after 38 h of fed-batch fermentation on glucose. The bacterial isolate utilized only 2–13% of carbon for its growth and energy metabolism, while 87–98% of carbon was converted to lactic acid at an overall volumetric productivity of 5 g l−1 h−1. At 13 h of fermentation, the volumetric productivity of lactate production reached 10.3 g l−1 h−1, which is the highest ever reported for microbial production of lactic acid. The lactic acid produced was of high purity as formation of other metabolites was less than 0.1%. The present investigation demonstrates a new opportunity for enhanced production of lactic acid with potential for reduced purification costs. PMID:24894833
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Human milk is a source of lactic acid bacteria for the infant gut.
Martín, Rocío; Langa, Susana; Reviriego, Carlota; Jimínez, Esther; Marín, María L; Xaus, Jordi; Fernández, Leonides; Rodríguez, Juan M
2003-12-01
To investigate whether human breast milk contains potentially probiotic lactic acid bacteria, and therefore, whether it can be considered a synbiotic food. Study design Lactic acid bacteria were isolated from milk, mammary areola, and breast skin of eight healthy mothers and oral swabs and feces of their respective breast-fed infants. Some isolates (178 from each mother and newborn pair) were randomly selected and submitted to randomly amplified polymorphic DNA (RAPD) polymerase chain reaction analysis, and those that displayed identical RAPD patterns were identified by 16S rDNA sequencing. Within each mother and newborn pair, some rod-shaped lactic acid bacteria isolated from mammary areola, breast milk, and infant oral swabs and feces displayed identical RAPD profiles. All of them, independently from the mother and child pair, were identified as Lactobacillus gasseri. Similarly, among coccoid lactic acid bacteria from these different sources, some shared an identical RAPD pattern and were identified as Enterococcus faecium. In contrast, none of the lactic acid bacteria isolated from breast skin shared RAPD profiles with lactic acid bacteria of the other sources. Breast-feeding can be a significant source of lactic acid bacteria to the infant gut. Lactic acid bacteria present in milk may have an endogenous origin and may not be the result of contamination from the surrounding breast skin.
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Glycolysis in energy metabolism during seizures.
Yang, Heng; Wu, Jiongxing; Guo, Ren; Peng, Yufen; Zheng, Wen; Liu, Ding; Song, Zhi
2013-05-15
Studies have shown that glycolysis increases during seizures, and that the glycolytic metabolite lactic acid can be used as an energy source. However, how lactic acid provides energy for seizures and how it can participate in the termination of seizures remains unclear. We reviewed possible mechanisms of glycolysis involved in seizure onset. Results showed that lactic acid was involved in seizure onset and provided energy at early stages. As seizures progress, lactic acid reduces the pH of tissue and induces metabolic acidosis, which terminates the seizure. The specific mechanism of lactic acid-induced acidosis involves several aspects, which include lactic acid-induced inhibition of the glycolytic enzyme 6-diphosphate kinase-1, inhibition of the N-methyl-D-aspartate receptor, activation of the acid-sensitive 1A ion channel, strengthening of the receptive mechanism of the inhibitory neurotransmitter γ-minobutyric acid, and changes in the intra- and extracellular environment.
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Glycolysis in energy metabolism during seizures☆
Yang, Heng; Wu, Jiongxing; Guo, Ren; Peng, Yufen; Zheng, Wen; Liu, Ding; Song, Zhi
2013-01-01
Studies have shown that glycolysis increases during seizures, and that the glycolytic metabolite lactic acid can be used as an energy source. However, how lactic acid provides energy for seizures and how it can participate in the termination of seizures remains unclear. We reviewed possible mechanisms of glycolysis involved in seizure onset. Results showed that lactic acid was involved in seizure onset and provided energy at early stages. As seizures progress, lactic acid reduces the pH of tissue and induces metabolic acidosis, which terminates the seizure. The specific mechanism of lactic acid-induced acidosis involves several aspects, which include lactic acid-induced inhibition of the glycolytic enzyme 6-diphosphate kinase-1, inhibition of the N-methyl-D-aspartate receptor, activation of the acid-sensitive 1A ion channel, strengthening of the receptive mechanism of the inhibitory neurotransmitter γ-minobutyric acid, and changes in the intra- and extracellular environment. PMID:25206426
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21 CFR 862.1450 - Lactic acid test system.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Lactic acid test system. 862.1450 Section 862.1450....1450 Lactic acid test system. (a) Identification. A lactic acid test system is a device intended to measure lactic acid in whole blood and plasma. Lactic acid measurements that evaluate the acid-base status...
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21 CFR 862.1450 - Lactic acid test system.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Lactic acid test system. 862.1450 Section 862.1450....1450 Lactic acid test system. (a) Identification. A lactic acid test system is a device intended to measure lactic acid in whole blood and plasma. Lactic acid measurements that evaluate the acid-base status...
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21 CFR 862.1450 - Lactic acid test system.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Lactic acid test system. 862.1450 Section 862.1450....1450 Lactic acid test system. (a) Identification. A lactic acid test system is a device intended to measure lactic acid in whole blood and plasma. Lactic acid measurements that evaluate the acid-base status...
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21 CFR 862.1450 - Lactic acid test system.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Lactic acid test system. 862.1450 Section 862.1450....1450 Lactic acid test system. (a) Identification. A lactic acid test system is a device intended to measure lactic acid in whole blood and plasma. Lactic acid measurements that evaluate the acid-base status...
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Tangwatcharin, Pussadee; Khopaibool, Prapaporn
2012-07-01
The objective of this study was to investigate the in vitro activities of virgin coconut oil, lauric acid and monolaurin in combination with lactic acid against two strains of Staphylococcus aureus, ATCC 25923 and an isolate from a pig carcass, by determination of Fractional Bactericidal Concentration Index (FBCI), time-kill method, as well as scanning and transmission electron microscopy. Minimum bactericidal concentrations (MBC) of lauric acid, monolaurin and lactic acid were 3.2 mg/ml, 0.1 mg/ml and 0.4% (v/v), respectively. The effects of lauric acid + lactic acid and monolaurin + lactic acid combinations were synergistic against both strains, exhibiting FBCIs of 0.25 and 0.63, respectively. In time-kill studies, lauric acid and monolaurin + lactic acid combinations added at their minimum inhibitory concentrations produced a bactericidal effect. The induction of stress in non-stressed cells was dependent on the type and concentration of antimicrobial. This resulted in a loss and change of the cytoplasm and membrane in cells of the bacterium. In contrast, virgin coconut oil (10%) was not active against S. aureus. The bacterial counts found in pork loin treated with lauric acid and monolaurin alone were significantly higher (p <0.05) than those treated with both lipids in combination with lactic acid at sub-inhibitory concentrations. The color, odor and overall acceptability of the pork loins were adversely affected by treatment with the three lipids and lactic acid alone but when combinations of the agents were used the sensory quality was acceptable.
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Bordes, Brianne M; Walia, Hina; Sebastian, Roby; Martin, David; Tumin, Dmitry; Tobias, Joseph D
2017-12-01
Lactic acid and base deficit (BD) values are frequently monitored in the intensive care unit and operating room setting to evaluate oxygenation, ventilation, cardiac output, and peripheral perfusion. Although generally obtained from an arterial cannula, such access may not always be available. The current study prospectively investigates the correlation of arterial and peripheral venous values of BD and lactic acid. The study cohort included 48 patients. Arterial BD values ranged from -8 to 4 mEq/L and peripheral venous BD values ranged from -8 to 4 mEq/L. Arterial lactic acid values ranged from 0.36 to 2.45 μmol/L and peripheral venous lactic acid values ranged from 0.38 to 4 μmol/L. The arterial BD (-0.4 ± 2.2 mEq/L) was not significantly different from the peripheral venous BD (-0.6 ± 2.2 mEq/L). The arterial lactic acid (1.0 ± 0.5 μmol/L) was not significantly different from the peripheral venous lactic acid (1.1 ± 0.6 μmol/L). Pearson correlation coefficients demonstrated a very high correlation between arterial and peripheral venous BD ( r = .88, P < .001) and between arterial and peripheral venous lactic acid ( r = .67, P < .001). Bland-Altman plots of both pairs of measures showed that the majority of observations fell within the 95% limits of agreement. Least-squares regression indicated that a 1-unit increase in arterial BD corresponded to a 0.9-unit increase in peripheral venous BD (95% confidence interval [CI]: 0.7-1.0; P < .001) and a 1-unit increase in arterial lactic acid corresponded to a 0.9-unit increase in peripheral venous lactic acid (95% CI: 0.6-1.2; P < .001). These data demonstrate that there is a clinically useful correlation between arterial and peripheral venous lactic acid and BD values.
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Visualisation of insect tracheal systems by lactic acid immersion.
Ruan, Y; Li, Y; Zhang, M; Chen, X; Liu, Z; Wang, S; Jiang, S
2018-05-15
The endeavours to reveal the tracheal system of insects and some arachnids has a long history. The traditional way to observe a tracheal system in an insect body is by utilising the glycerin immersion method. In this study, we developed the lactic acid immersion method, which reveals a more complete tracheal system. By mounting various types of live specimens or body parts directly into lactic acid, multiple intact and complex tracheal systems were clearly visualised. The lactic acid immersion contributed to revealing tracheal systems by penetrating body tissue while reserving enough time for observation before the penetration of the tracheae. Preliminary comparisons were conducted between lactic acid and other mediae, including glycerin. It turned out that lactic acid immersion provides better details and more distinct structures. In our test, the optimal time for observing the tracheal system was 10-25 min after the organism was immersed in lactic acid. © 2018 The Authors Journal of Microscopy © 2018 Royal Microscopical Society.
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Enhancement of L(+)-Lactic Acid Production of Immobilized Rhizopus Oryzae Implanted by Ion Beams
NASA Astrophysics Data System (ADS)
Fan, Yonghong; Yang, Yingge; Zheng, Zhiming; Li, Wen; Wang, Peng; Yao, Liming; Yu, Zengliang
2008-02-01
Immobilized Rhizopus oryzae culturing may be a solution to the inhibited production of L(+)-lactic acid in submerged fermentation, which is caused by aggregated mycelia floc. In the present study, a R. oryzae mutant (RL6041) with a 90% conversion rate of glucose into L-lactic acid was obtained by N+ implantation under the optimized conditions of a beam energy of 15 keV and a dose of 2.6 × 1015 ions/cm2. Using polyurethane foam as the immobilization matrix, the optimal L-lactic acid production conditions were determined as 4 mm polyurethane foam, 150 r/min, 50 g/L ~ 80 g/L of initial glucose, 38°C and pH 6.0. 15-cycle repeated productions of L-lactic acid by immobilized RL6041 were performed under the optimized culturing conditions and over 80% of the glucose was converted into L-lactic acid in 30 hours on average. The results show that immobilized RL6041 is a promising candidate for continuous L-lactic acid production.
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Asmat, Shakila; Shaukat, Fouzia; Asmat, Raheela; Bakhat, Hafiz Faiq Siddique Gul; Asmat, Tauseef M
2018-03-01
To compare the efficacy of Saccharomyces boulardii and lactic acid producing probiotics in addition to usual treatment regimen to cure diarrhea among children (6 months to 5 years of age). Randomized controlled trial. Department of Pediatrics, Sheikh Zayed Hospital, Lahore, from February to July 2015. Children suffering from acute diarrhea were orally administered Saccharomyces boulardii and lactic acid producing probiotics for 5 days. The efficacy of administered probiotics was monitored. Patients were given Saccharomyces boulardii and lactic acid producing probiotics randomly to remove the bias. Two hundred patients randomly selected for trials; out of which, 100 were treated with Saccharomyces boulardii while the other 100 were supplemented with lactic acid concomitantly along with conventional diarrhea treatment. Results indicated that Saccharomyces boulardii treatment group has significantly higher efficacy rate (45%) compared to lactic acid producing probiotics (26%). This study concluded that Saccharomyces boulardii has a better efficacy compared to lactic acid and may be adopted as a probiotic of choice.
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NASA Astrophysics Data System (ADS)
Yanagisawa, Mitsunori; Nakamura, Kanami; Nakasaki, Kiyohiko
In the present study, biomass waste raw materials including paper mill sludge, bamboo, sea lettuce, and shochu residue (from a distiller) and crude enzymes derived from inedible and discarded scallop parts were used to produce L-lactic acid for the raw material of biodegradable plastic poly-lactic acid. The activities of cellulase and amylase in the crude enzymes were 22 and 170units/L, respectively, and L-lactic acid was produced from every of the above mentioned biomass wastes, by the method of liquid-state simultaneous saccharification and fermentation (SSF) . The L-lactic acid concentrations produced from sea lettuce and shochu residue, which contain high concentration of starch were 3.6 and 9.3g/L, respectively, and corresponded to greater than 25% of the conversion of glucans contained in these biomass wastes. Furthermore, using the solid state SSF method, concentrations as high as 13g/L of L-lactic acid were obtained from sea lettuce and 26g/L were obtained from shochu residue.
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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.
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Singhvi, Mamata; Zendo, Takeshi; Iida, Hiroshi; Gokhale, Digambar; Sonomoto, Kenji
2017-12-01
The present study revealed the effect of nitrogen sources on lactic acid production and stimulation of d- and l-lactate dehydrogenases (LDH) of parent Lactobacillus lactis NCIM 2368 and its mutant RM2-24 generated after UV mutagenesis. Both the parent and mutant strains were evaluated for d-lactic acid production in control and modified media. The modified media did not show remarkable effect on lactic acid production in case of parent whereas mutant exhibited significant enhancement in d-lactic acid production along with the appearance of l-lactic acid in the broth. Both LDH activities and specific activities were found to be higher in mutant than the parent strain. These results suggested that the diammonium hydrogen phosphate in modified media triggered the expression of LDH genes leading to enhanced lactic acid production. This observation has been proved by studying the expression levels of d- and l-LDH genes of parent and mutant in control and modified media using quantitative RT-PCR technique. In case of mutant, the transcriptional levels of d-LDH and l-LDH increased ∼17 fold and ∼1.38 fold respectively in modified medium compared to the values obtained with control medium. In case of parent, no significant change in transcriptional levels of d- and l-LDH was found when the cells were grown in either control medium or modified medium. This study suggested that the mutant, RM2-24 has l-LDH gene which is expressed in presence of (NH 4 ) 2 HPO 4 resulting in l-lactic acid production. Co-production of l-lactic acid in d-lactic acid fermentation may be detrimental in the PLA production. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
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Wang, Limin; Cai, Yumeng; Zhu, Lingfeng; Guo, Honglian
2014-01-01
Bacillus coagulans 2-6 is an excellent producer of optically pure l-lactic acid. However, little is known about the mechanism of synthesis of the highly optically pure l-lactic acid produced by this strain. Three enzymes responsible for lactic acid production—NAD-dependent l-lactate dehydrogenase (l-nLDH; encoded by ldhL), NAD-dependent d-lactate dehydrogenase (d-nLDH; encoded by ldhD), and glycolate oxidase (GOX)—were systematically investigated in order to study the relationship between these enzymes and the optical purity of lactic acid. Lactobacillus delbrueckii subsp. bulgaricus DSM 20081 (a d-lactic acid producer) and Lactobacillus plantarum subsp. plantarum DSM 20174 (a dl-lactic acid producer) were also examined in this study as comparative strains, in addition to B. coagulans. The specific activities of key enzymes for lactic acid production in the three strains were characterized in vivo and in vitro, and the levels of transcription of the ldhL, ldhD, and GOX genes during fermentation were also analyzed. The catalytic activities of l-nLDH and d-nLDH were different in l-, d-, and dl-lactic acid producers. Only l-nLDH activity was detected in B. coagulans 2-6 under native conditions, and the level of transcription of ldhL in B. coagulans 2-6 was much higher than that of ldhD or the GOX gene at all growth phases. However, for the two Lactobacillus strains used in this study, ldhD transcription levels were higher than those of ldhL. The high catalytic efficiency of l-nLDH toward pyruvate and the high transcription ratios of ldhL to ldhD and ldhL to the GOX gene provide the key explanations for the high optical purity of l-lactic acid produced by B. coagulans 2-6. PMID:25217009
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Wang, Limin; Cai, Yumeng; Zhu, Lingfeng; Guo, Honglian; Yu, Bo
2014-12-01
Bacillus coagulans 2-6 is an excellent producer of optically pure l-lactic acid. However, little is known about the mechanism of synthesis of the highly optically pure l-lactic acid produced by this strain. Three enzymes responsible for lactic acid production-NAD-dependent l-lactate dehydrogenase (l-nLDH; encoded by ldhL), NAD-dependent d-lactate dehydrogenase (d-nLDH; encoded by ldhD), and glycolate oxidase (GOX)-were systematically investigated in order to study the relationship between these enzymes and the optical purity of lactic acid. Lactobacillus delbrueckii subsp. bulgaricus DSM 20081 (a d-lactic acid producer) and Lactobacillus plantarum subsp. plantarum DSM 20174 (a dl-lactic acid producer) were also examined in this study as comparative strains, in addition to B. coagulans. The specific activities of key enzymes for lactic acid production in the three strains were characterized in vivo and in vitro, and the levels of transcription of the ldhL, ldhD, and GOX genes during fermentation were also analyzed. The catalytic activities of l-nLDH and d-nLDH were different in l-, d-, and dl-lactic acid producers. Only l-nLDH activity was detected in B. coagulans 2-6 under native conditions, and the level of transcription of ldhL in B. coagulans 2-6 was much higher than that of ldhD or the GOX gene at all growth phases. However, for the two Lactobacillus strains used in this study, ldhD transcription levels were higher than those of ldhL. The high catalytic efficiency of l-nLDH toward pyruvate and the high transcription ratios of ldhL to ldhD and ldhL to the GOX gene provide the key explanations for the high optical purity of l-lactic acid produced by B. coagulans 2-6. Copyright © 2014, American Society for Microbiology. All Rights Reserved.
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l-(+)-Lactic acid production by Lactobacillus rhamnosus B103 from dairy industry waste.
Bernardo, Marcela Piassi; Coelho, Luciana Fontes; Sass, Daiane Cristina; Contiero, Jonas
2016-01-01
Lactic acid, which can be obtained through fermentation, is an interesting compound because it can be utilized in different fields, such as in the food, pharmaceutical and chemical industries as a bio-based molecule for bio-refinery. In addition, lactic acid has recently gained more interest due to the possibility of manufacturing poly(lactic acid), a green polymer that can replace petroleum-derived plastics and be applied in medicine for the regeneration of tissues and in sutures, repairs and implants. One of the great advantages of fermentation is the possibility of using agribusiness wastes to obtain optically pure lactic acid. The conventional batch process of fermentation has some disadvantages such as inhibition by the substrate or the final product. To avoid these problems, this study was focused on improving the production of lactic acid through different feeding strategies using whey, a residue of agribusiness. The downstream process is a significant bottleneck because cost-effective methods of producing high-purity lactic acid are lacking. Thus, the investigation of different methods for the purification of lactic acid was one of the aims of this work. The pH-stat strategy showed the maximum production of lactic acid of 143.7g/L. Following purification of the lactic acid sample, recovery of reducing sugars and protein and color removal were 0.28%, 100% and 100%, respectively. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.
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Ye, Tingting; Li, Xiang; Zhang, Ting; Su, Yinglong; Zhang, Wenjuan; Li, Jun; Gan, Yanfei; Zhang, Ai; Liu, Yanan; Xue, Gang
2018-06-01
Bio-refinery of food waste and waste activated sludge to high value-added chemicals, such as lactic acid, has attracted particular interest in recent years. In this paper, the effect of copper (II) dosing to the organic waste fermentation system on lactic acid production was evaluated, which proved to be a promising method to stimulate high yield of lactic acid (77.0% higher than blank) at dosage of 15 μM-Cu 2+ /g VSS. As mechanism study suggested, copper addition enhanced the activity of α-glycosidase and glycolysis, which increased the substrate for subsequent acidification; whereas, the high dosage (70 μM-Cu 2+ /g VSS) inhibited the conversion of lactic acid to VFA, thus stabilized lactic acid concentration. Microbial community study revealed that small amount of copper (II) at 15 μM/g VSS resulted in the proliferation of Lactobacillus to 82.6%, which mainly produced lactic acid. Finally, the variation of functional capabilities implied that the proposed homeostatic system II was activated at relatively low concentration of copper. Meanwhile, membrane transport function and carbohydrate metabolism were also strengthened. This study provides insights into the effect of copper (II) on the enhancement of lactic acid production from co-fermentation of food waste and waste activated sludge. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Cocrystallization as a tool to solve deliquescence issues: The case of L-lactic acid
NASA Astrophysics Data System (ADS)
de Maere d'Aertrycke, J. B.; Robeyns, K.; Willocq, J.; Leyssens, T.
2017-08-01
L-Lactic acid is an organic acid used in various fields such as food, cosmetic or pharmaceutical industry. It furthermore is the building-block of poly-lactic acid, a biodegradable and bioavailable polymer. Still, handling L-lactic acid under its solid form remains less straightforward mainly due to its deliquescent behavior, a phase transition from the solid to the dissolved state resulting from air humidity absorption. If several techniques are already known to avoid or reduce deliquescence, the use of cocrystallization in this context is still poorly investigated. In this paper, we investigate whether cocrystallization can be used as a suitable solution for deliquescence in the case of L-lactic acid. Out of 32 possible coformers tested, four were found to form cocrystals with L-lactic acid and the crystal structures of 1:1 L-lactic acid:D-tryptophan and 1:1 L-lactic acid:3-nitrobenzamide were determined. The hygroscopic behavior of these latter two was studied and compared to the behavior of pure L-lactic acid. Significant improvement was observed: dynamic vapor sorption at 25 °C revealed that water absorbed at 90% relative humidity dropped from 1.3157 g/gsample to 0.0017 g/gsample or 0.0299 g/gsample, with cocrystals of D-tryptophan and 3-nitrobenzamide respectively. This illustrates the effectiveness of cocrystallization as a tool to treat deliquescent materials.
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The importance of lactic acid in migraines and fibromyalgia.
de Sá Ribeiro, Guido Assis Cachuba; Scola, Rosana Hermínia; Piovesan, Elcio Juliato; Wollmann Junior, Darley Rugeri; Paiva, Eduardo Dos Santos; da Cunha, Claudio Leinig Pereira; Werneck, Lineu Cesar
2015-01-01
Lactic acid is a byproduct of both muscle metabolism and the central nervous system. Changes in metabolism are related to various physiological and pathological conditions. The aim of this study was to determine the relationship between migraine and fibromyalgia with the levels of lactic acid in the blood. We study of 93 patients was divided into five groups: 1) patients with fibromyalgia (n=20); 2) episodic migraine (n=20); 3) chronic migraine (n=20); 4) fibromyalgia and episodic migraine (n= 13); and 5) fibromyalgia and chronic migraine (n=20), and 20 healthy subjects (control group). Blood levels of lactic acid were measured at four different time points: at rest, during aerobic exercise, during anaerobic physical activity and while resting after anaerobic exercise. Lactic acid increased in all groups during anaerobic physical activity without predominance for either group. During aerobic physical activity, all groups increased lactic acid levels, but the increase was more expressive in the chronic migraine group and the chronic migraine with fibromyalgia group without statistical significance. We did not found abnormalities involving the metabolism of lactic acid in episodic and chronic migraine with or without fibromyalgia. Copyright © 2015 Elsevier Editora Ltda. All rights reserved.
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Lactic acid and methane: improved exploitation of biowaste potential.
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.
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Cell immobilization for production of lactic acid biofilms do it naturally.
Dagher, Suzanne F; Ragout, Alicia L; Siñeriz, Faustino; Bruno-Bárcena, José M
2010-01-01
Interest in natural cell immobilization or biofilms for lactic acid fermentation has developed considerably over the last few decades. Many studies report the benefits associated with biofilms as industrial methods for food production and for wastewater treatment, since the formation represents a protective means of microbial growth offering survival advantages to cells in toxic environments. The formation of biofilms is a natural process in which microbial cells adsorb to a support without chemicals or polymers that entrap the cells and is dependent on the reactor environment, microorganism, and characteristics of the support. These unique characteristics enable biofilms to cause chronic infections, disease, food spoilage, and devastating effects as in microbial corrosion. Their distinct resistance to toxicity, high biomass potential, and improved stability over cells in suspension make biofilms a good tool for improving the industrial economics of biological lactic acid production. Lactic acid bacteria and specific filamentous fungi are the main sources of biological lactic acid. Over the past two decades, studies have focused on improving the lactic acid volumetric productivity through reactor design development, new support materials, and improvements in microbial production strains. To illustrate the operational designs applied to the natural immobilization of lactic acid producing microorganisms, this chapter presents the results of a search for optimum parameters and how they are affected by the physical, chemical, and biological variables of the process. We will place particular emphasis upon the relationship between lactic acid productivity attained by various types of reactors, supports, media formulations, and lactic acid producing microorganisms. Copyright (c) 2010 Elsevier Inc. All rights reserved.
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M2-like macrophage polarization in high lactic acid-producing head and neck cancer.
Ohashi, Toshimitsu; Aoki, Mitsuhiro; Tomita, Hiroyuki; Akazawa, Takashi; Sato, Katsuya; Kuze, Bunya; Mizuta, Keisuke; Hara, Akira; Nagaoka, Hitoshi; Inoue, Norimitsu; Ito, Yatsuji
2017-06-01
Reprogramming of glucose metabolism in tumor cells is referred to as the Warburg effect and results in increased lactic acid secretion into the tumor microenvironment. We have previously shown that lactic acid has important roles as a pro-inflammatory and immunosuppressive mediator and promotes tumor progression. In this study, we examined the relationship between the lactic acid concentration and expression of LDHA and GLUT1, which are related to the Warburg effect, in human head and neck squamous cell carcinoma (HNSCC). Tumors expressing lower levels of LDHA and GLUT1 had a higher concentration of lactic acid than those with higher LDHA and GLUT1 expression. Lactic acid also suppressed the expression of LDHA and GLUT1 in vitro. We previously reported that lactic acid enhances expression of an M2 macrophage marker, ARG1, in murine macrophages. Therefore, we investigated the relationship between the lactic acid concentration and polarization of M2 macrophages in HNSCC by measuring the expression of M2 macrophage markers, CSF1R and CD163, normalized using a pan-macrophage marker, CD68. Tumors with lower levels of CD68 showed a higher concentration of lactic acid, whereas those with higher levels of CSF1R showed a significantly higher concentration of lactic acid. A similar tendency was observed for CD163. These results suggest that tumor-secreted lactic acid is linked to the reduction of macrophages in tumors and promotes induction of M2-like macrophage polarization in human HNSCC. © 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.
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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.
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Wei, Liujing; Yang, Xuepeng; Gao, Keliang; Lin, Jinping; Yang, Shengli; Hua, Qiang; Wei, Dongzhi
2010-09-01
Although Gluconobacter oxydans can convert 1,2-propanediol to D: -(-)-lactic acid, the enzyme(s) responsible for the conversion has remain unknown. In this study, the membrane-bound alcohol dehydrogenase (ADH) of Gluconobacter oxydans DSM 2003 was purified and confirmed to be essential for the process of D: -(-)-lactic acid production by gene knockout and complementation studies. A 25 percent decrease in D: -(-)-lactic acid production was found for the aldehyde dehydrogenase (ALDH) deficient strain of G. oxydans DSM 2003, indicating that this enzyme is involved in the reaction but not necessary. It is the first report that reveals the function of ADH and ALDH in the biooxidation of 1,2-propanediol to D: -(-)-lactic acid by G. oxydans DSM 2003.
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Yi, Xia; Zhang, Peng; Sun, Jiaoe; Tu, Yi; Gao, Qiuqiang; Zhang, Jian; Bao, Jie
2016-01-10
Pediococcus acidilactici TY112 producing L-lactic acid and P. acidilactici ZP26 producing D-lactic acid, were engineered from the wild-type P. acidilactici DQ2 by ldhD or ldh gene disruption, and the robustness of the wild-type strain to the inhibitors derived from lignocellulose pretreatment was maintained well. In simultaneous saccharification and fermentation (SSF), 77.66 g L(-1) of L-lactic acid and 76.76 g L(-1) of D-lactic acid were obtained at 25% (w/w) solids content of dry dilute acid pretreated and biodetoxified corn stover feedstock. L- and D-Lactic acid yield and productivity were highly dependent on the inhibitor removal extent due to the significant down-regulation on the expressions of ldh and ldhD encoding lactate dehydrogenase by inhibitor, especially syringaldehyde and vanillin at the low concentrations. This study provided a prototype of industrial process for high titer L- and D-lactic acid production from lignocellulose feedstock. Copyright © 2015 Elsevier B.V. All rights reserved.
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Optimisation of lactic acid fermentation for improved vinegar flavour during rosy vinegar brewing.
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.
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The effect of lactic acid bacteria on cocoa bean fermentation.
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.
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Wang, Jingxuan; Zhao, Peng; Li, Ying; Xu, Lida; Tian, Pingfang
2018-04-05
Klebsiella pneumoniae is a promising industrial species for bioproduction of bulk chemicals such as 1,3-propanediol, 2,3-butanediol and 3-hydroxypropionic acid (3-HP). However, lactic acid is a troublesome by-product when optimizing for 3-HP production. Therefore, it is highly desirable to minimize lactic acid. Here, we show that lactic acid synthesis can be largely blocked by an engineered CRISPR interference (CRISPRi) system in K. pneumoniae. EGFP was recruited as a reporter of this CRISPRi system. Fluorescence assay of this CRISPRi system showed that enhanced green fluorescent protein (EGFP) expression level was repressed by 85-90%. To further test this CRISPRi system, guide RNAs were designed to individually or simultaneously target four lactate-producing enzyme genes. Results showed that all lactate-producing enzyme genes were significantly repressed. Notably, D-lactate dehydrogenase (ldhA) was shown to be the most influential enzyme for lactic acid formation in micro-aerobic conditions, as inhibiting ldhA alone led to lactic acid level similar to simultaneously repressing four genes. In shake flask cultivation, the strain coexpressing puuC (an aldehyde dehydrogenase catalyzing 3-hydroxypropionaldehyde to 3-HP) and dCas9-sgRNA inhibiting ldhA produced 1.37-fold 3-HP relative to the reference strain. Furthermore, in bioreactor cultivation, this CRISPRi strain inhibiting ldhA produced 36.7 g/L 3-HP, but only generated 1 g/L lactic acid. Clearly, this engineered CRISPRi system largely simplified downstream separation of 3-HP from its isomer lactic acid, an extreme challenge for 3-HP bioprocess. This study offers a deep understanding of lactic acid metabolism in diverse species, and we believe that this CRISPRi system will facilitate biomanufacturing and functional genome studies of K. pneumoniae or beyond.
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Yousuf, Ahasa; Bastidas-Oyanedel, Juan-Rodrigo; Schmidt, Jens Ejbye
2018-04-28
Food waste landfilling causes environmental degradation, and this work assesses a sustainable food valorization technique. In this study, food waste is converted into lactic acid in a batch assembly by dark fermentation without pH control and without the addition of external inoculum at 37 °C. The effect of total solid (TS), enzymatic and aeration pretreatment was investigated on liquid products concentration and product yield. The maximum possible TS content was 34% of enzymatic pretreated waste, and showed the highest lactic acid concentration of 52 g/L, with a lactic acid selectivity of 0.6 g lactic /g totalacids . The results indicated that aeration pretreatment does not significantly improve product concentration or yield. Non-pretreated waste in a 29% TS system showed a lactic acid concentration of 31 g/L. The results showed that enzymatic pretreated waste at TS of 34% results in the highest production of lactic acid. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Wang, Shi-Fan; Guo, Chao-Lun; Cui, Ke-Ke; Zhu, Yan-Ting; Ding, Jun-Xiong; Zou, Xin-Yue; Li, Yi-Hang
2015-09-01
Lactic acid has been used as a bio-based green solvent to study the ultrasound-assisted scale-up synthesis. We report here, for the first time, on the novel and scalable process for synthesis of pyrrole derivatives in lactic acid solvent under ultrasonic radiation. Eighteen pyrrole derivatives have been synthesized in lactic acid solvent under ultrasonic radiation and characterized by (1)H NMR, IR, ESI MS. The results show, under ultrasonic radiation, lactic acid solvent can overcome the scale-up challenges and exhibited many advantages, such as bio-based origin, shorter reaction time, lower volatility, higher yields, and ease of isolating the products. Copyright © 2015 Elsevier B.V. All rights reserved.
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Ju, Si Yeon; Kim, Jin Ho; Lee, Pyung Cheon
2016-01-01
Lactic acid has been approved by the United States Food and Drug Administration as Generally Regarded As Safe (GRAS) and is commonly used in the cosmetics, pharmaceutical, and food industries. Applications of lactic acid have also emerged in the plastics industry. Lactic acid bacteria (LAB), such as Leuconostoc and Lactobacillus , are widely used as lactic acid producers for food-related and biotechnological applications. Nonetheless, industrial mass production of lactic acid in LAB is a challenge mainly because of growth inhibition caused by the end product, lactic acid. Thus, it is important to improve acid tolerance of LAB to achieve balanced cell growth and a high titer of lactic acid. Recently, adaptive evolution has been employed as one of the strategies to improve the fitness and to induce adaptive changes in bacteria under specific growth conditions, such as acid stress. Wild-type Leuconostoc mesenteroides was challenged long term with exogenously supplied lactic acid, whose concentration was increased stepwise (for enhancement of lactic acid tolerance) during 1 year. In the course of the adaptive evolution at 70 g/L lactic acid, three mutants (LMS50, LMS60, and LMS70) showing high specific growth rates and lactic acid production were isolated and characterized. Mutant LMS70, isolated at 70 g/L lactic acid, increased d-lactic acid production up to 76.8 g/L, which was twice that in the wild type (37.8 g/L). Proteomic, genomic, and physiological analyses revealed that several possible factors affected acid tolerance, among which a mutation of ATPase ε subunit (involved in the regulation of intracellular pH) and upregulation of intracellular ammonia, as a buffering system, were confirmed to contribute to the observed enhancement of tolerance and production of d-lactic acid. During adaptive evolution under lethal stress conditions, the fitness of L. mesenteroides gradually increased to accumulate beneficial mutations according to the stress level. The enhancement of acid tolerance in the mutants contributed to increased production of d-lactic acid. The observed genetic and physiological changes may systemically help remove protons and retain viability at high lactic acid concentrations.
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Nguyen, Cuong Mai; Kim, Jin-Seog; Nguyen, Thanh Ngoc; Kim, Seul Ki; Choi, Gyung Ja; Choi, Yong Ho; Jang, Kyoung Soo; Kim, Jin-Cheol
2013-10-01
Simultaneous saccharification and cofermentation (SSCF) of Curcuma longa waste biomass obtained after turmeric extraction to L- and D-lactic acid by Lactobacillus coryniformis and Lactobacillus paracasei, respectively, was investigated. This is a rich, starchy, agro-industrial waste with potential for use in industrial applications. After optimizing the fermentation of the biomass by adjusting nitrogen sources, enzyme compositions, nitrogen concentrations, and raw material concentrations, the SSCF process was conducted in a 7-l jar fermentor at 140 g dried material/L. The maximum lactic acid concentration, average productivity, reducing sugar conversion and lactic acid yield were 97.13 g/L, 2.7 g/L/h, 95.99% and 69.38 g/100 g dried material for L-lactic acid production, respectively and 91.61 g/L, 2.08 g/L/h, 90.53% and 65.43 g/100 g dried material for D-lactic acid production, respectively. The simple and efficient process described in this study could be utilized by C. longa residue-based lactic acid industries without requiring the alteration of plant equipment. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Alarcón, Pablo; Manosalva, Carolina; Conejeros, Ivan; Carretta, María D; Muñoz-Caro, Tamara; Silva, Liliana M R; Taubert, Anja; Hermosilla, Carlos; Hidalgo, María A; Burgos, Rafael A
2017-01-01
Bovine ruminal acidosis is of economic importance as it contributes to reduced milk and meat production. This phenomenon is mainly attributed to an overload of highly fermentable carbohydrate, resulting in increased d(-) lactic acid levels in serum and plasma. Ruminal acidosis correlates with elevated acute phase proteins in blood, along with neutrophil activation and infiltration into various tissues leading to laminitis and aseptic polysynovitis. Previous studies in bovine neutrophils indicated that d(-) lactic acid decreased expression of L-selectin and increased expression of CD11b to concentrations higher than 6 mM, suggesting a potential role in neutrophil adhesion onto endothelia. The two aims of this study were to evaluate whether d(-) lactic acid influenced neutrophil and endothelial adhesion and to trigger neutrophil extracellular trap (NET) production (NETosis) in exposed neutrophils. Exposure of bovine neutrophils to 5 mM d(-) lactic acid elevated NET release compared to unstimulated neutrophil negative controls. Moreover, this NET contains CD11b and histone H 4 citrullinated, the latter was dependent on PAD4 activation, a critical enzyme in DNA decondensation and NETosis. Furthermore, NET formation was dependent on d(-) lactic acid plasma membrane transport through monocarboxylate transporter 1 (MCT1). d(-) lactic acid enhanced neutrophil adhesion onto endothelial sheets as demonstrated by in vitro neutrophil adhesion assays under continuous physiological flow conditions, indicating that cell adhesion was a NET- and a CD11b/ICAM-1-dependent process. Finally, d(-) lactic acid was demonstrated for the first time to trigger NETosis in a PAD4- and MCT1-dependent manner. Thus, d(-) lactic acid-mediated neutrophil activation may contribute to neutrophil-derived pro-inflammatory processes, such as aseptic laminitis and/or polysynovitis in animals suffering acute ruminal acidosis.
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Amrutha, Balagopal; Sundar, Kothandapani; Shetty, Prathapkumar Halady
2017-10-01
Organic acids are known to be used as food preservatives due to their antimicrobial potential. This study evaluated the ability of three organic acids, namely, acetic acid, citric acid and lactic acid to manage E. coli and Salmonella sp. from fresh fruits and vegetables. Effect of these organic acids on biofilm forming ability and anti-quorum potential was also investigated. The effect of organic acids on inactivation of E. coli and Salmonella sp. on the surface of a selected vegetable (cucumber) was determined. The minimum inhibitory concentration of the organic acids were found to be 1.5, 2 and 0.2% in E. coli while it was observed to be 1, 1.5 and 1% in Salmonella sp. for acetic, citric and lactic acids respectively. Maximum inhibition of biofilm formation was recorded at 39.13% with lactic acid in E. coli and a minimum of 22.53% with citric acid in Salmonella sp. EPS production was affected in E. coli with lactic acid showing reduction by 13.42% while citric acid and acetic acid exhibited only 6.25% and 10.89% respectively. Swimming and swarming patterns in E. coli was notably affected by both acetic and lactic acids. Lactic and acetic acids showed higher anti-quorum sensing (QS) potential when compared to citric acid. 2% lactic acid showed a maximum inhibition of violacein production by 37.7%. Organic acids can therefore be used as potential quorum quenching agents in food industry. 2% lactic acid treatment on cucumber demonstrated that it was effective in inactivating E. coli and Salmonella sp. There was 1 log reduction in microbial count over a period of 6 days after the lactic acid treatment. Thus, organic acids can act as effective potential sanitizers in reducing the microbial load associated with fresh fruits and vegetables. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Maas, Ronald H. W.; Bakker, Robert R.; Jansen, Mickel L. A.; Visser, Diana; de Jong, Ed; Eggink, Gerrit
2008-01-01
Conventional processes for lignocellulose-to-organic acid conversion requires pretreatment, enzymatic hydrolysis, and microbial fermentation. In this study, lime-treated wheat straw was hydrolyzed and fermented simultaneously to lactic acid by an enzyme preparation and Bacillus coagulans DSM 2314. Decrease in pH because of lactic acid formation was partially adjusted by automatic addition of the alkaline substrate. After 55 h of incubation, the polymeric glucan, xylan, and arabinan present in the lime-treated straw were hydrolyzed for 55%, 75%, and 80%, respectively. Lactic acid (40.7 g/l) indicated a fermentation efficiency of 81% and a chiral l(+)-lactic acid purity of 97.2%. In total, 711 g lactic acid was produced out of 2,706 g lime-treated straw, representing 43% of the overall theoretical maximum yield. Approximately half of the lactic acid produced was neutralized by fed-batch feeding of lime-treated straw, whereas the remaining half was neutralized during the batch phase with a Ca(OH)2 suspension. Of the lime added during the pretreatment of straw, 61% was used for the neutralization of lactic acid. This is the first demonstration of a process having a combined alkaline pretreatment of lignocellulosic biomass and pH control in fermentation resulting in a significant saving of lime consumption and avoiding the necessity to recycle lime. PMID:18247027
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Cascade Production of Lactic Acid from Universal Types of Sugars Catalyzed by Lanthanum Triflate.
Liu, Dajiang; Kim, Kwang Ho; Sun, Jian; Simmons, Blake A; Singh, Seema
2018-02-09
Lignocellulosic biomass conversion into value-added platform chemicals in the non-toxic, water-tolerant Lewis acid, and water solutions bears the hallmark of green chemistry. Lactic acid derived from biomass is an important chemical building block for biodegradable polymers such as polylactide. Herein, a universal method of converting lignocellulosic sugars into lactic acid using catalytic amount of water-stable Lewis acid La(OTf) 3 is demonstrated. The lignocellulosic sugars studied in this work include 1) pyrolytic sugars from pyrolysis oil, and 2) sugars derived from ionic liquid (IL)-pretreated biomass. Under moderate conditions (250 °C, 1 h), levoglucosan (major pyrolytic sugar), glucose, and xylose were converted into lactic acid with carbon-based molar yields of 75, 74, and 61 %, respectively. Furthermore, roughly 49 mol % (based on levoglucosan) and 74 wt % (relative to pretreated biomass) of lactic acid were obtained from the conversion of pyrolytic sugars and sugar-rich fraction after lignin removal from switchgrass, respectively. To our knowledge, this is the first reported conversion of pyrolytic sugar into lactic acid by chemocatalysis and also lignocellulosic sugars are converted into lactic acid without hydrolysis. This approach could potentially be extended to other lignocellulosic sugars after simple removal of lignin from biomass pretreatment, rendering moderate to high yields of lactic acid. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Zhao, Jinfang; Xu, Liyuan; Wang, Yongze; Zhao, Xiao; Wang, Jinhua; Garza, Erin; Manow, Ryan; Zhou, Shengde
2013-06-07
Polylactic acid (PLA), a biodegradable polymer, has the potential to replace (at least partially) traditional petroleum-based plastics, minimizing "white pollution". However, cost-effective production of optically pure L-lactic acid is needed to achieve the full potential of PLA. Currently, starch-based glucose is used for L-lactic acid fermentation by lactic acid bacteria. Due to its competition with food resources, an alternative non-food substrate such as cellulosic biomass is needed for L-lactic acid fermentation. Nevertheless, the substrate (sugar stream) derived from cellulosic biomass contains significant amounts of xylose, which is unfermentable by most lactic acid bacteria. However, the microorganisms that do ferment xylose usually carry out heterolactic acid fermentation. As a result, an alternative strain should be developed for homofermentative production of optically pure L-lactic acid using cellulosic biomass. In this study, an ethanologenic Escherichia coli strain, SZ470 (ΔfrdBC ΔldhA ΔackA ΔpflB ΔpdhR ::pflBp6-acEF-lpd ΔmgsA), was reengineered for homofermentative production of L-lactic acid from xylose (1.2 mole xylose = > 2 mole L-lactic acid), by deleting the alcohol dehydrogenase gene (adhE) and integrating the L-lactate dehydrogenase gene (ldhL) of Pediococcus acidilactici. The resulting strain, WL203, was metabolically evolved further through serial transfers in screw-cap tubes containing xylose, resulting in the strain WL204 with improved anaerobic cell growth. When tested in 70 g L-1 xylose fermentation (complex medium), WL204 produced 62 g L-1 L-lactic acid, with a maximum production rate of 1.631 g L-1 h-1 and a yield of 97% based on xylose metabolized. HPLC analysis using a chiral column showed that an L-lactic acid optical purity of 99.5% was achieved by WL204. These results demonstrated that WL204 has the potential for homofermentative production of L-lactic acid using cellulosic biomass derived substrates, which contain a significant amount of xylose.
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Zhang, Yitong; Qian, Zijun; Liu, Peng; Liu, Lei; Zheng, Zhaojuan; Ouyang, Jia
2018-02-01
To get rid of the dependence on lactic acid neutralizer, a simple and economical approach for efficient in situ separation and production of L-lactic acid was established by Bacillus coagulans using weak basic anion-exchange resin. During ten tested resins, the 335 weak basic anion-exchange resins demonstrated the highest adsorption capacity and selectivity for lactic acid recovery. The adsorption study of the 335 resins for lactic acid confirmed that it is an efficient adsorbent under fermentation condition. Langmuir models gave a good fit to the equilibrium data at 50 °C and the maximum adsorption capacity for lactic acid by 335 resins was about 402 mg/g. Adsorption kinetic experiments showed that pseudo-second-order kinetics model gave a good fit to the adsorption rate. When it was used for in situ fermentation, the yield of L-lactic acid by B. coagulans CC17 was close to traditional fermentation and still maintained at about 82% even after reuse by ten times. These results indicated that in situ separation and production of L-lactic acid using the 335 resins were efficient and feasible. This process could greatly reduce the dosage of neutralizing agent and potentially be used in industry.
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Angermayr, S. Andreas; Correddu, Danilo; Kern, Ramona; Hagemann, Martin; Hellingwerf, Klaas J.
2015-01-01
Both enantiomers of lactic acid, l-lactic acid and d-lactic acid, can be produced in a sustainable way by a photosynthetic microbial cell factory and thus from CO2, sunlight, and water. Several properties of polylactic acid (a polyester of polymerized lactic acid) depend on the controlled blend of these two enantiomers. Recently, cyanobacterium Synechocystis sp. strain PCC6803 was genetically modified to allow formation of either of these two enantiomers. This report elaborates on the d-lactic acid production achieved by the introduction of a d-specific lactate dehydrogenase from the lactic acid bacterium Leuconostoc mesenteroides into Synechocystis. A typical batch culture of this recombinant strain initially shows lactic acid production, followed by a phase of lactic acid consumption, until production “outcompetes” consumption at later growth stages. We show that Synechocystis is able to use d-lactic acid, but not l-lactic acid, as a carbon source for growth. Deletion of the organism's putative d-lactate dehydrogenase (encoded by slr1556), however, does not eliminate this ability with respect to d-lactic acid consumption. In contrast, d-lactic acid consumption does depend on the presence of glycolate dehydrogenase GlcD1 (encoded by sll0404). Accordingly, this report highlights the need to match a product of interest of a cyanobacterial cell factory with the metabolic network present in the host used for its synthesis and emphasizes the need to understand the physiology of the production host in detail. PMID:26682849
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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.
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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.
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Extractive Fermentation of Lactic Acid in Lactic Acid Bacteria Cultivation: A Review.
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.
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Extractive Fermentation of Lactic Acid in Lactic Acid Bacteria Cultivation: A Review
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
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The role of monocarboxylate transporters in uptake of lactic acid in HeLa cells.
Cheeti, Sravanthi; Warrier, Bharat K; Lee, Chi H
2006-11-15
This study was aimed to identify the monocarboxylate transporters (MCTs) in HeLa cells and to delineate their role in transportation of L-lactic acid. The functional role of MCTs in lactic acid transport was evaluated at various mucosal pHs (4.5-7.4) or in the presence of various loading doses (0.2-2mM) of lactic acid, MCT substrates (nicotinic acid, n-butyric acid, etc.) and inhibitors (alpha-cyano-4-hydroxycinnamate and para-chloromercuribenzoic acid). The molecular properties of MCTs were characterized using reverse transcription-polymerase chain reaction (RT-PCR). The uptake rate of lactic acid by HeLa cells significantly increased from 0.353+/-0.052 to 1.103+/-0.196 micromol/mg protein as the extra-cellular pH changed from 7.4 to 4.5, indicating that activities of MCT were mediated through H(+)-linked mechanism. The uptake profile of lactic acid followed the saturable process with the K(m) value of 0.53 mM. The uptake rate of lactic acid is concentration dependent and is reduced in the presence of MCT inhibitors. MCT isoforms 1, 5 and 6 in HeLa cells were identified by RT-PCR. HeLa cell line can be used as an effective screening tool for intravaginally administered drugs targeted toward MCT.
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Kuanyshev, Nurzhan; Ami, Diletta; Signori, Lorenzo; Porro, Danilo; Morrissey, John P; Branduardi, Paola
2016-08-01
The ability of Zygosaccharomyces bailii to grow at low pH and in the presence of considerable amounts of weak organic acids, at lethal condition for Saccharomyces cerevisiae, increased the interest in the biotechnological potential of the yeast. To understand the mechanism of tolerance and growth effect of weak acids on Z. bailii, we evaluated the physiological and macromolecular changes of the yeast exposed to sub lethal concentrations of lactic acid. Lactic acid represents one of the important commodity chemical which can be produced by microbial fermentation. We assessed physiological effect of lactic acid by bioreactor fermentation using synthetic media at low pH in the presence of lactic acid. Samples collected from bioreactors were stained with propidium iodide (PI) which revealed that, despite lactic acid negatively influence the growth rate, the number of PI positive cells is similar to that of the control. Moreover, we have performed Fourier Transform Infra-Red (FTIR) microspectroscopy analysis on intact cells of the same samples. This technique has been never applied before to study Z. bailii under this condition. The analyses revealed lactic acid induced macromolecular changes in the overall cellular protein secondary structures, and alterations of cell wall and membrane physico-chemical properties. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Photoautotrophic production of D-lactic acid in an engineered cyanobacterium
2013-01-01
Background The world faces the challenge to develop sustainable technologies to replace thousands of products that have been generated from fossil fuels. Microbial cell factories serve as promising alternatives for the production of diverse commodity chemicals and biofuels from renewable resources. For example, polylactic acid (PLA) with its biodegradable properties is a sustainable, environmentally friendly alternative to polyethylene. At present, PLA microbial production is mainly dependent on food crops such as corn and sugarcane. Moreover, optically pure isomers of lactic acid are required for the production of PLA, where D-lactic acid controls the thermochemical and physical properties of PLA. Henceforth, production of D-lactic acid through a more sustainable source (CO2) is desirable. Results We have performed metabolic engineering on Synechocystis sp. PCC 6803 for the phototrophic synthesis of optically pure D-lactic acid from CO2. Synthesis of optically pure D-lactic acid was achieved by utilizing a recently discovered enzyme (i.e., a mutated glycerol dehydrogenase, GlyDH*). Significant improvements in D-lactic acid synthesis were achieved through codon optimization and by balancing the cofactor (NADH) availability through the heterologous expression of a soluble transhydrogenase. We have also discovered that addition of acetate to the cultures improved lactic acid production. More interestingly, 13C-pathway analysis revealed that acetate was not used for the synthesis of lactic acid, but was mainly used for synthesis of certain biomass building blocks (such as leucine and glutamate). Finally, the optimal strain was able to accumulate 1.14 g/L (photoautotrophic condition) and 2.17 g/L (phototrophic condition with acetate) of D-lactate in 24 days. Conclusions We have demonstrated the photoautotrophic production of D-lactic acid by engineering a cyanobacterium Synechocystis 6803. The engineered strain shows an excellent D-lactic acid productivity from CO2. In the late growth phase, the lactate production rate by the engineered strain reached a maximum of ~0.19 g D-lactate/L/day (in the presence of acetate). This study serves as a good complement to the recent metabolic engineering work done on Synechocystis 6803 for L-lactate production. Thereby, our study may facilitate future developments in the use of cyanobacterial cell factories for the commercial production of high quality PLA. PMID:24274114
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Photoautotrophic production of D-lactic acid in an engineered cyanobacterium.
Varman, Arul M; Yu, Yi; You, Le; Tang, Yinjie J
2013-11-25
The world faces the challenge to develop sustainable technologies to replace thousands of products that have been generated from fossil fuels. Microbial cell factories serve as promising alternatives for the production of diverse commodity chemicals and biofuels from renewable resources. For example, polylactic acid (PLA) with its biodegradable properties is a sustainable, environmentally friendly alternative to polyethylene. At present, PLA microbial production is mainly dependent on food crops such as corn and sugarcane. Moreover, optically pure isomers of lactic acid are required for the production of PLA, where D-lactic acid controls the thermochemical and physical properties of PLA. Henceforth, production of D-lactic acid through a more sustainable source (CO2) is desirable. We have performed metabolic engineering on Synechocystis sp. PCC 6803 for the phototrophic synthesis of optically pure D-lactic acid from CO2. Synthesis of optically pure D-lactic acid was achieved by utilizing a recently discovered enzyme (i.e., a mutated glycerol dehydrogenase, GlyDH*). Significant improvements in D-lactic acid synthesis were achieved through codon optimization and by balancing the cofactor (NADH) availability through the heterologous expression of a soluble transhydrogenase. We have also discovered that addition of acetate to the cultures improved lactic acid production. More interestingly, (13)C-pathway analysis revealed that acetate was not used for the synthesis of lactic acid, but was mainly used for synthesis of certain biomass building blocks (such as leucine and glutamate). Finally, the optimal strain was able to accumulate 1.14 g/L (photoautotrophic condition) and 2.17 g/L (phototrophic condition with acetate) of D-lactate in 24 days. We have demonstrated the photoautotrophic production of D-lactic acid by engineering a cyanobacterium Synechocystis 6803. The engineered strain shows an excellent D-lactic acid productivity from CO2. In the late growth phase, the lactate production rate by the engineered strain reached a maximum of ~0.19 g D-lactate/L/day (in the presence of acetate). This study serves as a good complement to the recent metabolic engineering work done on Synechocystis 6803 for L-lactate production. Thereby, our study may facilitate future developments in the use of cyanobacterial cell factories for the commercial production of high quality PLA.
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Matsumoto, Michiaki; Panigrahi, Abhishek; Murakami, Yuuki; Kondo, Kazuo
2011-01-01
Biodegradable polymers have attracted much attention from an environmental point of view. Optically pure lactic acid that can be prepared by fermentation is one of the important raw materials for biodegradable polymer. The separation and purification of lactic acid from the fermentation broth are the major portions of the production costs. We proposed the application of supported ionic liquid membranes to recovering lactic acid. In this paper, the effect of ionic liquids, such as Aliquat 336, CYPHOS IL-101, CYPHOS IL-102, CYPHOS IL-104, CYPHOS IL-109 and CYPHOS IL-111 on the lactic acid permeation have been studied. Aliquat 336, CYPHOS IL-101 and CYPHOS IL-102 were found to be the best membrane solvents as far as membrane stability and permeation of lactic acid are concerned. CYPHOS IL-109 and CYPHOS IL-111 were found to be unsuitable, as they leak out from the pores of the supported liquid membrane (SLM), thereby allowing free transport of lactic acid as well as hydrochloric acid. CYPHOS IL-102 was found to be the most adequate (Permeation rate = 60.41%) among these ionic liquids as far as the separation of lactic acid is concerned. The permeation mechanisms, by which ionic liquid-water complexes act as the carrier of lactate and hydrochloric acid, were proposed. The experimental permeation results have been obtained as opposed to the expected values from the solution-diffusion mechanism. PMID:24957613
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Maple sap as a rich medium to grow probiotic lactobacilli and to produce lactic acid.
Cochu, A; Fourmier, D; Halasz, A; Hawari, J
2008-12-01
To demonstrate the feasibility of growing lactobacilli and producing lactic acid using maple sap as a sugar source and to show the importance of oligosaccharides in the processes. Two maple sap samples (Cetta and Pinnacle) and purified sucrose were used as carbon sources in the preparation of three culture media. Compared with the sucrose-based medium, both maple sap-based media produced increased viable counts in two strains out of five by a factor of four to seven. Maple sap-based media also enhanced lactic acid production in three strains. Cetta sap was found to be more efficient than Pinnacle sap in stimulating lactic acid production and, was also found to be richer in various oligosaccharides. The amendment of the Pinnacle-based medium with trisaccharides significantly stimulated Lactobacillus acidophilus AC-10 to grow and produce lactic acid. Maple sap, particularly if rich in oligosaccharides, represents a good carbon source for the growth of lactobacilli and the production of lactic acid. This study provides a proof-of-concept, using maple sap as a substrate for lactic acid production and for the development of a nondairy probiotic drink.
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Tanaka, Takaaki; Hoshina, Masahiro; Tanabe, Suguru; Sakai, Kenji; Ohtsubo, Sadami; Taniguchi, Masayuki
2006-01-01
Production of d-lactic acid from rice bran, one of the most abundant agricultural by-products in Japan, is studied. Lactobacillus delbrueckii subsp. delbrueckii IFO 3202 and defatted rice bran powder after squeezing rice oil were used for the production. Since the rice bran contains polysaccharides as starch and cellulose, we coupled saccharification with amylase and cellulase to lactic acid fermentation. The indigenous bacteria in the rice bran produced racemic lactic acid in the saccharification at pH 6.0-6.8. Thus the pH was controlled at 5.0 to suppress the growth of the indigenous bacteria. L. delbrueckii IFO 3202 produced 28 kgm(-3) lactic acid from 100 kgm(-3) rice bran after 36 h at 37 degrees C. The yield based on the amount of sugars soluble after 36-h hydrolysis of the bran by amylase and cellulase (36 kgm(-3) from 100 kgm(-3) of the bran) was 78%. The optical purity of produced d-lactic acid was 95% e.e.
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Singhvi, Mamata; Jadhav, Akanksha; Gokhale, Digambar
2013-10-01
The production of D-lactic acid by Lactobacillus lactis RM2-24 was investigated using modified media to increase the efficiency of the fermentation process. The results indicated that the addition of 5 g/l peptone and 1 g/l (NH4)2HPO4 enhanced D-lactic acid production by 32%, as compared to that obtained from non supplemented media, with a productivity of 3.0 g/l/h. Lactate dehydrogenase (LDH) expression profile in these different media was studied which resulted in appearance of additional LDH isoform produced by cells when they were grown in HSYE supplemented with (NH4)2HPO4. The additional LDH appears to be L-LDH contributing to production of L-lactic acid in the fermented broth. This is totally new information in the lactic acid fermentation and could be very useful to industries engaged in D-lactic acid production. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Aldunate, Muriel; Srbinovski, Daniela; Hearps, Anna C.; Latham, Catherine F.; Ramsland, Paul A.; Gugasyan, Raffi; Cone, Richard A.; Tachedjian, Gilda
2015-01-01
Lactic acid and short chain fatty acids (SCFAs) produced by vaginal microbiota have reported antimicrobial and immune modulatory activities indicating their potential as biomarkers of disease and/or disease susceptibility. In asymptomatic women of reproductive-age the vaginal microbiota is comprised of lactic acid-producing bacteria that are primarily responsible for the production of lactic acid present at ~110 mM and acidifying the vaginal milieu to pH ~3.5. In contrast, bacterial vaginosis (BV), a dysbiosis of the vaginal microbiota, is characterized by decreased lactic acid-producing microbiota and increased diverse anaerobic bacteria accompanied by an elevated pH>4.5. BV is also characterized by a dramatic loss of lactic acid and greater concentrations of mixed SCFAs including acetate, propionate, butyrate, and succinate. Notably women with lactic acid-producing microbiota have more favorable reproductive and sexual health outcomes compared to women with BV. Regarding the latter, BV is associated with increased susceptibility to sexually transmitted infections (STIs) including HIV. In vitro studies demonstrate that lactic acid produced by vaginal microbiota has microbicidal and virucidal activities that may protect against STIs and endogenous opportunistic bacteria as well as immune modulatory properties that require further characterization with regard to their effects on the vaginal mucosa. In contrast, BV-associated SCFAs have far less antimicrobial activity with the potential to contribute to a pro-inflammatory vaginal environment. Here we review the composition of lactic acid and SCFAs in respective states of eubiosis (non-BV) or dysbiosis (BV), their effects on susceptibility to bacterial/viral STIs and whether they have inherent microbicidal/virucidal and immune modulatory properties. We also explore their potential as biomarkers for the presence and/or increased susceptibility to STIs. PMID:26082720
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Smerilli, Marina; Neureiter, Markus; Wurz, Stefan; Haas, Cornelia; Frühauf, Sabine; Fuchs, Werner
2015-04-01
Lactic acid is an important biorefinery platform chemical. The use of thermophilic amylolytic microorganisms to produce lactic acid by fermentation constitutes an efficient strategy to reduce operating costs, including raw materials and sterilization costs. A process for the thermophilic production of lactic acid by Geobacillus stearothermophilus directly from potato starch was characterized and optimized. Geobacillus stearothermophilus DSM 494 was selected out of 12 strains screened for amylolytic activity and the ability to form lactic acid as the major product of the anaerobic metabolism. In total more than 30 batches at 3-l scale were run at 60 °C under non-sterile conditions. The process developed produced 37 g L -1 optically pure (98%) L-lactic acid in 20 h from 50 g L -1 raw potato starch. As co-metabolites smaller amounts (<7% w/v) of acetate, formate and ethanol were formed. Yields of lactic acid increased from 66% to 81% when potato residues from food processing were used as a starchy substrate in place of raw potato starch. Potato starch and residues were successfully converted to lactic acid by G. stearothermophilus . The process described in this study provides major benefits in industrial applications and for the valorization of starch-rich waste streams. © 2015 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Lactic Acid Bacteria from Kefir Increase Cytotoxicity of Natural Killer Cells to Tumor Cells.
Yamane, Takuya; Sakamoto, Tatsuji; Nakagaki, Takenori; Nakano, Yoshihisa
2018-03-27
The Japanese fermented beverage, homemade kefir, contains six lactic acid bacteria: Lactococcus. lactis subsp. Lactis , Lactococcus . lactis subsp. Cremoris , Lactococcus. Lactis subsp. Lactis biovar diacetylactis , Lactobacillus plantarum , Leuconostoc meseuteroides subsp. Cremoris and Lactobacillus casei . In this study, we found that a mixture of the six lactic acid bacteria from kefir increased the cytotoxicity of human natural killer KHYG-1 cells to human chronic myelogenous leukemia K562 cells and colorectal tumor HCT116 cells. Furthermore, levels of mRNA expression and secretion of IFN-γ (interferon gamma) increased in KHYG-1 cells that had been treated with the six lactic acid bacteria mixture from kefir. The results suggest that the six lactic acid bacteria mixture from kefir has strong effects on natural immunity and tumor cell cytotoxicity.
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Lactic Acid Bacteria from Kefir Increase Cytotoxicity of Natural Killer Cells to Tumor Cells
Yamane, Takuya; Sakamoto, Tatsuji; Nakagaki, Takenori; Nakano, Yoshihisa
2018-01-01
The Japanese fermented beverage, homemade kefir, contains six lactic acid bacteria: Lactococcus. lactis subsp. Lactis, Lactococcus. lactis subsp. Cremoris, Lactococcus. Lactis subsp. Lactis biovar diacetylactis, Lactobacillus plantarum, Leuconostoc meseuteroides subsp. Cremoris and Lactobacillus casei. In this study, we found that a mixture of the six lactic acid bacteria from kefir increased the cytotoxicity of human natural killer KHYG-1 cells to human chronic myelogenous leukemia K562 cells and colorectal tumor HCT116 cells. Furthermore, levels of mRNA expression and secretion of IFN-γ (interferon gamma) increased in KHYG-1 cells that had been treated with the six lactic acid bacteria mixture from kefir. The results suggest that the six lactic acid bacteria mixture from kefir has strong effects on natural immunity and tumor cell cytotoxicity. PMID:29584690
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Müller, Gerdt; Kalyani, Dayanand Chandrahas; Horn, Svein Jarle
2017-03-01
Enzymatic catalysis plays a key role in the conversion of lignocellulosic biomass to fuels and chemicals such as lactic acid. In the last decade, the efficiency of commercial cellulase cocktails has increased significantly, in part due to the inclusion of lytic polysaccharide monooxygenases (LPMOs). However, the LPMOs' need for molecular oxygen to break down cellulose demands reinvestigations of process conditions. In this study, we evaluate the efficiency of lactic acid production from steam-exploded birch using an LPMO-containing cellulase cocktail in combination with lactic acid bacteria, investigating both separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF). While the SSF set up generally has been considered to be more efficient because it avoids sugar accumulation which may inhibit the cellulases, the SHF set up in our study yielded 26-32% more lactic acid than the SSF. This was mainly due to competition for oxygen between LPMOs and the fermenting organisms in the SSF process, which resulted in reduced LPMO activity and thus less efficient saccharification of the lignocellulosic substrate. By means of aeration it was possible to activate the LPMOs in the SSF, but less lactic acid was produced due to a shift in metabolic pathways toward production of acetic acid. Overall, this study shows that lactic acid can be produced efficiently from lignocellulosic biomass, but that the use of LPMO-containing cellulase cocktails in fermentation processes demands re-thinking of traditional process set ups due to the requirement of oxygen in the saccharification step. Biotechnol. Bioeng. 2017;114: 552-559. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
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Validation of a 2 percent lactic acid antimicrobial rinse for mobile poultry slaughter operations.
Killinger, Karen M; Kannan, Aditi; Bary, Andy I; Cogger, Craig G
2010-11-01
Poultry processing antimicrobial interventions are critical for pathogen control, and organic, mobile operations in Washington seek alternatives to chlorine. Laboratory and field studies (three replications each) evaluated lactic acid efficacy as a chlorine alternative. For the laboratory study, retail-purchased, conventionally processed chicken wings inoculated with Salmonella were randomly assigned to the following treatments: Salmonella inoculation followed by no treatment (10 wings) or by 3-min rinses of water, 50 to 100 ppm of chlorine, or 2% lactic acid (20 wings for each rinse treatment). Wings were sampled for Salmonella enumeration on xylose lysine desoxycholate agar. During pastured poultry processing at mobile slaughter units for each field study replication, 20 chicken carcasses were randomly assigned to each treatment: untreated control or 3-min immersion in lactic acid or chlorine. Whole-carcass rinses were examined for aerobic plate count (APC) on tryptic soy agar and coliforms on violet red bile agar. Untreated controls were also examined for Salmonella. In the laboratory study, lactic acid produced a significant (P < 0.01) Salmonella reduction compared with the inoculated no-rinse, water, and chlorine treatments, which were statistically similar to each other. In the field study, no Salmonella was detected on untreated controls. Lactic acid produced significant >2-log (P < 0.01) reductions in APC and coliforms, whereas chlorine resulted in slight, but significant 0.4-log reductions (P < 0.01) and 0.21-log reductions (P < 0.05) in APC and coliforms compared with untreated controls. Considering laboratory and field studies, lactic acid produced greater reductions in Salmonella, APC, and coliforms, validating its effectiveness as a chlorine alternative in mobile poultry slaughter operations.
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21 CFR 184.1061 - Lactic acid.
Code of Federal Regulations, 2014 CFR
2014-04-01
....1061 Lactic acid. (a) Lactic acid (C3H6O3, CAS Reg. Nos.: dl mixture, 598-82-3; l-isomer, 79-33-4; d... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Lactic acid. 184.1061 Section 184.1061 Food and... hydrolysis to lactic acid. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed...
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Influence of lactic acid on the two-phase anaerobic digestion of kitchen wastes.
Zhang, Bo; Cai, Wei-min; He, Pin-jing
2007-01-01
To evaluate the influence of lactic acid on the methanogenesis, anaerobic digestion of kitchen wastes was firstly conducted in a two-phase anaerobic digestion process, and performance of two digesters fed with lactic acid and glucose was subsequently compared. The results showed that the lactic acid was the main fermentation products of hydrolysis-acidification stage in the two-phase anaerobic digestion process for kitchen wastes. The lactic acid concentration constituted approximately 50% of the chemical oxygen demand (COD) concentration in the hydrolysis-acidification liquid. The maximum organic loading rate was lower in the digester fed with lactic acid than that fed with glucose. Volatile fatty acids (VFAs) and COD removal were deteriorated in the methanogenic reactor fed with lactic acid compared to that fed with glucose. The specific methanogenic activity (SMA) declined to 0.343 g COD/(gVSSxd) when the COD loading were designated as 18.8 g/(Lxd) in the digester fed with lactic acid. The propionic acid accumulation occurred due to the high concentration of lactic acid fed. It could be concluded that avoiding the presence of the lactic acid is necessary in the hydrolysis-acidification process for the improvement of the two-phase anaerobic digestion process of kitchen wastes.
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Laube, Hendrik; Matysik, Frank-Michael; Schmidberger, Andreas; Mehlmann, Kerstin; Toursel, Andreas; Boden, Jana
2016-01-01
During the downstream process of bio-based bulk chemicals, organic impurities, mostly residues from the fermentation process, must be separated to obtain a pure and ready-to-market chemical. In this study, capillary electrophoresis was investigated for the non-targeting downstream process monitoring of organic impurities and simultaneous quantitative detection of lactic acid during the purification process of fermentatively produced lactic acid. The downstream process incorporated 11 separation units, ranging from filtration, adsorption and ion exchange to electrodialysis and distillation, and 15 different second-generation renewable feedstocks were processed into lactic acid. The identification of organic impurities was established through spiking and the utilization of an advanced capillary electrophoresis mass spectrometry system. A total of 53 % of the organic impurities were efficiently removed via bipolar electrodialysis; however, one impurity, pyroglutamic acid, was recalcitrant to separation. It was demonstrated that the presence of pyroglutamic acid disrupts the polymerization of lactic acid into poly lactic acid. Pyroglutamic acid was present in all lactic acid solutions, independent of the type of renewable resource or the bacterium applied. Pyroglutamic acid, also known as 5-oxoproline, is a metabolite in the glutathione cycle, which is present in all living microorganisms. pyroglutamic acid is found in many proteins, and during intracellular protein metabolism, N-terminal glutamic acid and glutamine residues can spontaneously cyclize to become pyroglutamic acid. Hence, the concentration of pyroglutamic acid in the lactic acid solution can only be limited to a certain amount. The present study proved the capillary electrophoresis system to be an important tool for downstream process monitoring. The high product concentration encountered in biological production processes did not hinder the capillary electrophoresis from separating and detecting organic impurities, even at minor concentrations. The coupling of the capillary electrophoresis with a mass spectrometry system allowed for the straightforward identification of the remaining critical impurity, pyroglutamic acid. Although 11 separation units were applied during the downstream process, the pyroglutamic acid concentration remained at 12,900 ppm, which was comparatively high. All organic impurities found were tracked by the capillary electrophoresis, allowing for further separation optimization.
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Liaud, Nadège; Rosso, Marie-Noëlle; Fabre, Nicolas; Crapart, Sylvaine; Herpoël-Gimbert, Isabelle; Sigoillot, Jean-Claude; Raouche, Sana; Levasseur, Anthony
2015-05-03
Lactic acid is the building block of poly-lactic acid (PLA), a biopolymer that could be set to replace petroleum-based plastics. To make lactic acid production cost-effective, the production process should be carried out at low pH, in low-nutrient media, and with a low-cost carbon source. Yeasts have been engineered to produce high levels of lactic acid at low pH from glucose but not from carbohydrate polymers (e.g. cellulose, hemicellulose, starch). Aspergilli are versatile microbial cell factories able to naturally produce large amounts of organic acids at low pH and to metabolize cheap abundant carbon sources such as plant biomass. However, they have never been used for lactic acid production. To investigate the feasibility of lactic acid production with Aspergillus, the NAD-dependent lactate dehydrogenase (LDH) responsible for lactic acid production by Rhizopus oryzae was produced in Aspergillus brasiliensis BRFM103. Among transformants, the best lactic acid producer, A. brasiliensis BRFM1877, integrated 6 ldhA gene copies, and intracellular LDH activity was 9.2 × 10(-2) U/mg. At a final pH of 1.6, lactic acid titer reached 13.1 g/L (conversion yield: 26%, w/w) at 138 h in glucose-ammonium medium. This extreme pH drop was subsequently prevented by switching nitrogen source from ammonium sulfate to Na-nitrate, leading to a final pH of 3 and a lactic acid titer of 17.7 g/L (conversion yield: 47%, w/w) at 90 h of culture. Final titer was further improved to 32.2 g/L of lactic acid (conversion yield: 44%, w/w) by adding 20 g/L glucose to the culture medium at 96 h. This strain was ultimately able to produce lactic acid from xylose, arabinose, starch and xylan. We obtained the first Aspergillus strains able to produce large amounts of lactic acid by inserting recombinant ldhA genes from R. oryzae into a wild-type A. brasiliensis strain. pH regulation failed to significantly increase lactic acid production, but switching nitrogen source and changing culture feed enabled a 1.8-fold increase in conversion yields. The strain produced lactic acid from plant biomass. Our findings make A. brasiliensis a strong contender microorganism for low-pH acid production from various complex substrates, especially hemicellulose.
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Lactic acid bacteria: promising supplements for enhancing the biological activities of kombucha.
Nguyen, Nguyen Khoi; Dong, Ngan Thi Ngoc; Nguyen, Huong Thuy; Le, Phu Hong
2015-01-01
Kombucha is sweetened black tea that is fermented by a symbiosis of bacteria and yeast embedded within a cellulose membrane. It is considered a health drink in many countries because it is a rich source of vitamins and may have other health benefits. It has previously been reported that adding lactic acid bacteria (Lactobacillus) strains to kombucha can enhance its biological functions, but in that study only lactic acid bacteria isolated from kefir grains were tested. There are many other natural sources of lactic acid bacteria. In this study, we examined the effects of lactic acid bacteria from various fermented Vietnamese food sources (pickled cabbage, kefir and kombucha) on kombucha's three main biological functions: glucuronic acid production, antibacterial activity and antioxidant ability. Glucuronic acid production was determined by high-performance liquid chromatography-mass spectrometry, antibacterial activity was assessed by the agar-well diffusion method and antioxidant ability was evaluated by determining the 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity. Four strains of food-borne pathogenic bacteria were used in our antibacterial experiments: Listeria monocytogenes ATCC 19111, Escherichia coli ATCC 8739, Salmonella typhimurium ATCC 14028 and Bacillus cereus ATCC 11778. Our findings showed that lactic acid bacteria strains isolated from kefir are superior to those from other sources for improving glucuronic acid production and enhancing the antibacterial and antioxidant activities of kombucha. This study illustrates the potential of Lactobacillus casei and Lactobacillus plantarum isolated from kefir as biosupplements for enhancing the bioactivities of kombucha.
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Alarcón, Pablo; Manosalva, Carolina; Conejeros, Ivan; Carretta, María D.; Muñoz-Caro, Tamara; Silva, Liliana M. R.; Taubert, Anja; Hermosilla, Carlos; Hidalgo, María A.; Burgos, Rafael A.
2017-01-01
Bovine ruminal acidosis is of economic importance as it contributes to reduced milk and meat production. This phenomenon is mainly attributed to an overload of highly fermentable carbohydrate, resulting in increased d(−) lactic acid levels in serum and plasma. Ruminal acidosis correlates with elevated acute phase proteins in blood, along with neutrophil activation and infiltration into various tissues leading to laminitis and aseptic polysynovitis. Previous studies in bovine neutrophils indicated that d(−) lactic acid decreased expression of L-selectin and increased expression of CD11b to concentrations higher than 6 mM, suggesting a potential role in neutrophil adhesion onto endothelia. The two aims of this study were to evaluate whether d(−) lactic acid influenced neutrophil and endothelial adhesion and to trigger neutrophil extracellular trap (NET) production (NETosis) in exposed neutrophils. Exposure of bovine neutrophils to 5 mM d(−) lactic acid elevated NET release compared to unstimulated neutrophil negative controls. Moreover, this NET contains CD11b and histone H4 citrullinated, the latter was dependent on PAD4 activation, a critical enzyme in DNA decondensation and NETosis. Furthermore, NET formation was dependent on d(−) lactic acid plasma membrane transport through monocarboxylate transporter 1 (MCT1). d(−) lactic acid enhanced neutrophil adhesion onto endothelial sheets as demonstrated by in vitro neutrophil adhesion assays under continuous physiological flow conditions, indicating that cell adhesion was a NET- and a CD11b/ICAM-1-dependent process. Finally, d(−) lactic acid was demonstrated for the first time to trigger NETosis in a PAD4- and MCT1-dependent manner. Thus, d(−) lactic acid-mediated neutrophil activation may contribute to neutrophil-derived pro-inflammatory processes, such as aseptic laminitis and/or polysynovitis in animals suffering acute ruminal acidosis. PMID:28861083
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Effect of fluoride on growth and acid production by Streptococcus mutans in dental plaque.
van der Hoeven, J S; Franken, H C
1984-01-01
The aim of this study was to measure the effect of fluoride on the production of organic acids by Streptococcus mutans in dental plaque. The effect was studied in a simplified model of dental plaque with gnotobiotic rats monoinfected with S. mutans Ny341. Adaptation of S. mutans to fluoride was induced by feeding one group of the rats on fluoride-containing diet and drinking water. No difference was found in the accumulation of S. mutans on the teeth between the fluoride-adapted and the control groups. However, there was a significant difference in the amount of lactic acid in metabolically resting plaque between the groups, lactic acid being lower in the fluoride-adapted plaque. At 5 min after a rinse containing 10% sucrose, a high level of lactic acid was found in plaque from animals not exposed to fluoride. Rinses containing 4 or 20 mM fluoride before the sucrose rinse significantly inhibited the lactic acid production in the control group. In the plaque from rats on fluoridated diet and drinking water the sucrose-induced production of lactic acid was not inhibited by a 4 mM fluoride rinse. Moreover, the production of lactic acid in the fluoride-adapted plaque was prolonged. The results indicate that due to fluoride adaptation the inhibition of acid production is unlikely to be important for the caries-preventive action of fluoride. PMID:6746094
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Ding, Xuemei; Lin, Shuhai; Weng, Hongbo; Liang, Jianying
2018-06-01
Lactic acid and 2-hydroxyglutaric acid are chiral metabolites that have two distinct d- and l-enantiomers with distinct biochemical properties. Perturbations of a single enantiomeric form have been found to be closely related to certain diseases. Therefore, the ability to differentiate the d and l enantiomers is important for these disease studies. Herein, we describe a method for the separation and determination of lactic acid and 2-hydroxyglutaric acid enantiomers by chiral derivatization (with l-menthol and acetyl chloride) combined with gas chromatography and mass spectrometry. The two pairs of above-mentioned enantiomers exhibited linear calibration curves with a correlation coefficient (R 2 ) exceeding 0.99. The measured data were accurate in the acceptable recovery range of 88.17-102.30% with inter- and intraday precisions (relative standard deviations) in the range of 4.23-17.26%. The limits of detection for d-lactic acid, l-lactic acid, d-2-hydroxyglutaric acid, and l-2-hydroxyglutaric acid were 0.13, 0.11, 1.12, and 1.16 μM, respectively. This method was successfully applied to analyze mouse plasma. The d-lactic acid levels in type 2 diabetes mellitus mouse plasma were observed to be significantly higher (P < 0.05, t-test) than those of normal mice, suggesting that d-lactic acid may serve as an indicator for type 2 diabetes mellitus. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Abdel-Rahman, Mohamed Ali; Sonomoto, Kenji
2016-10-20
There has been growing interest in the microbial production of optically pure lactic acid due to the increased demand for lactic acid-derived environmentally friendly products, for example biodegradable plastic (poly-lactic acid), as an alternative to petroleum-derived materials. To maximize the market uptake of these products, their cost should be competitive and this could be achieved by decreasing the production cost of the raw material, that is, lactic acid. It is of great importance to isolate and develop robust and highly efficient microbial lactic acid producers. Alongside the fermentative substrate and concentration, the yield and productivity of lactic acid are key parameters and major factors in determining the final production cost of lactic acid. In this review, we will discuss the current limitations and challenges for cost-efficient microbial production of optically pure lactic acid. The main obstacles to effective fermentation are the use of food resources, indirect utilization of polymeric sugars, sensitivity to inhibitory compounds released during biomass treatments, substrate inhibition, decreased lactic acid yield and productivity, inefficient utilization of mixed sugars, end product inhibition, increased use of neutralizing agents, contamination problems, and decreased optical purity of lactic acid. Furthermore, opportunities to address and overcome these limitations, either by fermentation technology or metabolic engineering approaches, will be introduced and discussed. Copyright © 2016 Elsevier B.V. All rights reserved.
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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.
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Bai, Dong-Mei; Zhao, Xue-Ming; Li, Xin-Gang; Xu, Shi-Min
2004-12-20
The effects of initial glucose concentration and calcium lactate concentration on the lactic acid production by the parent strain, Lactobacillus lactis BME5-18, were studied. The results of the experiments indicated that glucose and lactate repressed the cell growth and the lactic acid production by Lactobacillus lactis BME5-18. A L(+)-lactic acid overproducing strain, Lactobacillus lactis BME5-18M, was screened by mutagenizing the parent strain with ultraviolet (UV) light irradiation and selecting the high glucose and lactate calcium concentration repression resistant mutant. Starting with a concentration of 100g L(-1) glucose, the mutant produced 98.6 g L(-1) lactic acid after 60 h in flasks, 73.9% higher than that of the parent strain. The L(+)-lactic acid purity was 98.1% by weight based on the amount of total lactic acid. The culture of the parent strain could not be analyzed well by conventional metabolic flux analysis techniques, since some pyruvate were accumulated intracellularly. Therefore, a revised flux analysis method was proposed by introducing intracellular pyruvate pool. Further studies demonstrate that there is a high level of NADH oxidase activity (12.11 mmol mg(-1) min(-1)) in the parent strain. The molecular mechanisms of the strain improvement were proposed, i.e., the high level of NADH oxidase activity was eliminated and the uptake rate of glucose was increased from 82.1 C-mmol (g DW h)(-1) to 98.9 C-mmol (g DW h)(-1) by mutagenizing the parent strain with UV, and therefore the mutant strain converts mostly pyruvate to lactic acid with a higher productivity (1.76 g L(-1) h(-1)) than the parent strain (0.95 g L(-1) h(-1)).
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Kottman, R. M.; Kulkarni, Ajit A.; Smolnycki, Katie A.
2012-10-15
Rationale: Idiopathic pulmonary fibrosis (IPF) is a complex disease for which the pathogenesis is poorly understood. In this study, we identified lactic acid as a metabolite that is elevated in the lung tissue of patients with IPF. Objectives: This study examines the effect of lactic acid on myofibroblast differentiation and pulmonary fibrosis. Methods:We used metabolomic analysis to examine cellular metabolism in lung tissuefrom patients with IPFanddeterminedthe effects of lactic acid and lactate dehydrogenase-5 (LDH5) overexpression on myofibroblast differentiation and transforming growth factor (TGF)-b activation in vitro. Measurements and Main Results: Lactic acid concentrations from healthy and IPF lung tissue weremore » determined by nuclear magnetic resonance spectroscopy; a-smooth muscle actin, calponin, and LDH5 expression were assessed by Western blot of cell culture lysates. Lactic acid and LDH5 were significantly elevated in IPF lung tissue compared with controls. Physiologic concentrations of lactic acid induced myofibroblast differentiation via activation of TGF-b. TGF-b induced expression of LDH5 via hypoxia-inducible factor 1a (HIF1a). Importantly, overexpression of both HIF1a and LDH5 in human lung fibroblasts induced myofibroblast differentiation and synergized with low dose TGF-b to induce differentiation. Furthermore, inhibition of both HIF1a and LDH5 inhibited TGF-b–induced myofibroblast differentiation. Conclusions: We have identified the metabolite lactic acid as an important mediator of myofibroblast differentiation via a pHdependent activation of TGF-b. We propose that the metabolic milieu of the lung, and potentially other tissues, is an important driving force behind myofibroblast differentiation and potentially the initiation and progression of fibrotic disorders.« less
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Kottmann, Robert Matthew; Kulkarni, Ajit A.; Smolnycki, Katie A.; Lyda, Elizabeth; Dahanayake, Thinesh; Salibi, Rami; Honnons, Sylvie; Jones, Carolyn; Isern, Nancy G.; Hu, Jian Z.; Nathan, Steven D.; Grant, Geraldine; Phipps, Richard P.
2012-01-01
Rationale: Idiopathic pulmonary fibrosis (IPF) is a complex disease for which the pathogenesis is poorly understood. In this study, we identified lactic acid as a metabolite that is elevated in the lung tissue of patients with IPF. Objectives: This study examines the effect of lactic acid on myofibroblast differentiation and pulmonary fibrosis. Methods: We used metabolomic analysis to examine cellular metabolism in lung tissue from patients with IPF and determined the effects of lactic acid and lactate dehydrogenase-5 (LDH5) overexpression on myofibroblast differentiation and transforming growth factor (TGF)-β activation in vitro. Measurements and Main Results: Lactic acid concentrations from healthy and IPF lung tissue were determined by nuclear magnetic resonance spectroscopy; α-smooth muscle actin, calponin, and LDH5 expression were assessed by Western blot of cell culture lysates. Lactic acid and LDH5 were significantly elevated in IPF lung tissue compared with controls. Physiologic concentrations of lactic acid induced myofibroblast differentiation via activation of TGF-β. TGF-β induced expression of LDH5 via hypoxia-inducible factor 1α (HIF1α). Importantly, overexpression of both HIF1α and LDH5 in human lung fibroblasts induced myofibroblast differentiation and synergized with low-dose TGF-β to induce differentiation. Furthermore, inhibition of both HIF1α and LDH5 inhibited TGF-β–induced myofibroblast differentiation. Conclusions: We have identified the metabolite lactic acid as an important mediator of myofibroblast differentiation via a pH-dependent activation of TGF-β. We propose that the metabolic milieu of the lung, and potentially other tissues, is an important driving force behind myofibroblast differentiation and potentially the initiation and progression of fibrotic disorders. PMID:22923663
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Vaginal concentrations of lactic acid potently inactivate HIV
Aldunate, Muriel; Tyssen, David; Johnson, Adam; Zakir, Tasnim; Sonza, Secondo; Moench, Thomas; Cone, Richard; Tachedjian, Gilda
2013-01-01
Objectives When Lactobacillus spp. dominate the vaginal microbiota of women of reproductive age they acidify the vagina to pH <4.0 by producing ∼1% lactic acid in a nearly racemic mixture of d- and l-isomers. We determined the HIV virucidal activity of racemic lactic acid, and its d- and l-isomers, compared with acetic acid and acidity alone (by the addition of HCl). Methods HIV-1 and HIV-2 were transiently treated with acids in the absence or presence of human genital secretions at 37°C for different time intervals, then immediately neutralized and residual infectivity determined in the TZM-bl reporter cell line. Results l-lactic acid at 0.3% (w/w) was 17-fold more potent than d-lactic acid in inactivating HIVBa-L. Complete inactivation of different HIV-1 subtypes and HIV-2 was achieved with ≥0.4% (w/w) l-lactic acid. At a typical vaginal pH of 3.8, l-lactic acid at 1% (w/w) more potently and rapidly inactivated HIVBa-L and HIV-1 transmitter/founder strains compared with 1% (w/w) acetic acid and with acidity alone, all adjusted to pH 3.8. A final concentration of 1% (w/w) l-lactic acid maximally inactivated HIVBa-L in the presence of cervicovaginal secretions and seminal plasma. The anti-HIV activity of l-lactic acid was pH dependent, being abrogated at neutral pH, indicating that its virucidal activity is mediated by protonated lactic acid and not the lactate anion. Conclusions l-lactic acid at physiological concentrations demonstrates potent HIV virucidal activity distinct from acidity alone and greater than acetic acid, suggesting a protective role in the sexual transmission of HIV. PMID:23657804
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Process for the preparation of lactic acid and glyceric acid
Jackson, James E [Haslett, MI; Miller, Dennis J [Okemos, MI; Marincean, Simona [Dewitt, MI
2008-12-02
Hexose and pentose monosaccharides are degraded to lactic acid and glyceric acid in an aqueous solution in the presence of an excess of a strongly anionic exchange resin, such as AMBERLITE IRN78 and AMBERLITE IRA400. The glyceric acid and lactic acid can be separated from the aqueous solution. Lactic acid and glyceric acid are staple articles of commerce.
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Enhanced D-lactic acid production from renewable resources using engineered Lactobacillus plantarum.
Zhang, Yixing; Vadlani, Praveen V; Kumar, Amit; Hardwidge, Philip R; Govind, Revathi; Tanaka, Tsutomu; Kondo, Akihiko
2016-01-01
D-lactic acid is used as a monomer in the production of poly-D-lactic acid (PDLA), which is used to form heat-resistant stereocomplex poly-lactic acid. To produce cost-effective D-lactic acid by using all sugars derived from biomass efficiently, xylose-assimilating genes encoding xylose isomerase and xylulokinase were cloned into an L-lactate-deficient strain, Lactobacillus plantarum. The resulting recombinant strain, namely L. plantarum NCIMB 8826 ∆ldhL1-pLEM-xylAB, was able to produce D-lactic acid (at optical purity >99 %) from xylose at a yield of 0.53 g g(-1). Simultaneous utilization of glucose and xylose to produce D-lactic acid was also achieved by this strain, and 47.2 g L(-1) of D-lactic acid was produced from 37.5 g L(-1) glucose and 19.7 g L(-1) xylose. Corn stover and soybean meal extract (SBME) were evaluated as cost-effective medium components for D-lactic acid production. Optimization of medium composition using response surface methodology resulted in 30 % reduction in enzyme loading and 70 % reduction in peptone concentration. In addition, we successfully demonstrated D-lactic acid fermentation from corn stover and SBME in a fed-batch fermentation, which yielded 61.4 g L(-1) D-lactic acid with an overall yield of 0.77 g g(-1). All these approaches are geared to attaining high D-lactic acid production from biomass sugars to produce low-cost, highly thermostable biodegradable plastics.
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Zhang, Yixing; Kumar, Amit; Hardwidge, Philip R; Tanaka, Tsutomu; Kondo, Akihiko; Vadlani, Praveen V
2016-03-01
d-lactic acid is of great interest because of increasing demand for biobased poly-lactic acid (PLA). Blending poly-l-lactic acid with poly-d-lactic acid greatly improves PLA's mechanical and physical properties. Corn stover and sorghum stalks treated with 1% sodium hydroxide were investigated as possible substrates for d-lactic acid production by both sequential saccharification and fermentation and simultaneous saccharification and cofermentation (SSCF). A commercial cellulase (Cellic CTec2) was used for hydrolysis of lignocellulosic biomass and an l-lactate-deficient mutant strain Lactobacillus plantarum NCIMB 8826 ldhL1 and its derivative harboring a xylose assimilation plasmid (ΔldhL1-pCU-PxylAB) were used for fermentation. The SSCF process demonstrated the advantage of avoiding feedback inhibition of released sugars from lignocellulosic biomass, thus significantly improving d-lactic acid yield and productivity. d-lactic acid (27.3 g L(-1) ) and productivity (0.75 g L(-1) h(-1) ) was obtained from corn stover and d-lactic acid (22.0 g L(-1) ) and productivity (0.65 g L(-1) h(-1) ) was obtained from sorghum stalks using ΔldhL1-pCU-PxylAB via the SSCF process. The recombinant strain produced a higher concentration of d-lactic acid than the mutant strain by using the xylose present in lignocellulosic biomass. Our findings demonstrate the potential of using renewable lignocellulosic biomass as an alternative to conventional feedstocks with metabolically engineered lactic acid bacteria to produce d-lactic acid. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:271-278, 2016. © 2016 American Institute of Chemical Engineers.
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Beghini, J; Linhares, I M; Giraldo, P C; Ledger, W J; Witkin, S S
2015-11-01
Do metabolites in vaginal samples vary between women with different vaginal disorders. Cross-sectional study. Campinas, Brazil. Seventy-seven women (39.9%) with no vaginal disorder, 52 women (26.9%) with vulvovaginal candidiasis (VVC), 43 women (22.3%) with bacterial vaginosis (BV), and 21 women (10.9%) with cytolytic vaginosis (CTV). Concentrations of D- and L-lactic acid, extracellular matrix metalloproteinase inducer (EMMPRIN), and matrix metalloproteinase-8 (MMP-8), and the influence of Candida albicans on EMMPRIN production by cultured vaginal epithelial cells, were determined by enzyme-linked immunosorbent assay (ELISA). Associations were determined by the Mann-Whitney U-test and by Spearman's rank correlation test. Metabolite levels and their correlation with diagnoses. Vaginal concentrations of D- and L-lactic acid were reduced from control levels in BV (P < 0.0001); L-lactic acid levels were elevated in CTV (P = 0.0116). EMMPRIN and MMP-8 concentrations were elevated in VVC (P < 0.0001). EMMPRIN and L-lactic acid concentrations (P ≤ 0.008), but not EMMPRIN and D-lactic acid, were correlated in all groups. EMMPRIN also increased in proportion with the ratio of L- to D-lactic acid in controls and in women with BV (P ≤ 0.009). Concentrations of EMMPRIN and MMP-8 were correlated in controls and women with VVC (P ≤ 0.0002). Candida albicans induced EMMPRIN release from vaginal epithelial cells. Vaginal secretions from women with BV are deficient in D- and L-lactic acid, women with VVC have elevated EMMPRIN and MMP-8 levels, and women with CTV have elevated L-lactic acid levels. These deviations may contribute to the clinical signs, symptoms, and sequelae that are characteristic of these disorders. © 2014 Royal College of Obstetricians and Gynaecologists.
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Strain improvement of Lactobacillus lactis for D-lactic acid production.
Joshi, D S; Singhvi, M S; Khire, J M; Gokhale, D V
2010-04-01
Three mutants, isolated by repeated UV mutagenesis of Lactobacillus lactis NCIM 2368, produced increased D: -lactic acid concentrations. These mutants were compared with the wild type using 100 g hydrolyzed cane sugar/l in the fermentation medium. One mutant, RM2-24, produced 81 g lactic acid/l which was over three times that of the wild type. The highest D: -lactic acid (110 g/l) in batch fermentation was obtained with 150 g cane sugar/l with a 73% lactic acid yield. The mutant utilizes cellobiose efficiently, converting it into D-lactic acid suggesting the presence of cellobiase. Thus, this strain could be used to obtain D-lactic acid from cellulosic materials that are pre-hydrolyzed with cellulase.
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Efficacy of sanitizers in reducing Salmonella on pecan nutmeats during cracking and shelling.
Beuchat, Larry R; Mann, David A; Alali, Walid Q
2013-05-01
Studies were done to evaluate the efficacy of chlorine (200 to 1,000 μg/ml), lactic acid (0.5 to 2%), levulinic acid (0.5 to 2%), sodium dodecyl sulfate (SDS, 0.05%), lactic acid plus SDS, levulinic acid plus SDS, and a mixed peroxyacid sanitizer (Tsunami 200, 40 and 80 μg/ml) in killing Salmonella on or in immersion- and on surface-inoculated pecan nutmeats (U.S. Department of Agriculture medium pieces and mammoth halves). The addition of SDS to treatment solutions containing lactic acid or levulinic acid resulted in generally higher reductions of Salmonella, but differences in these reductions were not always significant. Lactic and levulinic acids (2%) containing SDS (0.05%) were equivalent in killing Salmonella on immersion-inoculated nutmeats. Tsunami 200 (40 μg/ml) was less lethal or equivalent to 1 or 2% lactic and levulinic acids, with or without 0.05% SDS. Reductions did not exceed 1.1 log CFU/g of immersion-inoculated pieces and halves, regardless of sanitizer concentration or treatment time (up to 20 min). Reductions on surface-inoculated pieces and halves were 0.7 to 2.6 log CFU/g and 1.2 to 3.0 log CFU/g, respectively. Treatment with 2% lactic acid plus SDS (0.05%) and Tsunami (80 μg/ml) was most effective in killing Salmonella on surface-inoculated pieces; treatment of halves with chlorine (1,000 μg/ml) or lactic acid (1 or 2%), with or without SDS, was most efficacious. Exposure of immersion-inoculated pecan pieces to chlorine (200 μg/ml), lactic acid (2%) and levulinic acid (2%) with or without SDS, and Tsunami (80 μg/ml) during intermittent vacuum (18 ± 2 mbar) and ambient atmospheric pressure treatments for up to 20 min reduced Salmonella by only 0.1 to 1.0 log CFU/g. These studies emphasize the importance of preventing contamination of pecan nutmeats with Salmonella. Once nuts are contaminated, the lethality of sanitizers tested in this study is minimal.
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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.
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Smerilli, Marina; Neureiter, Markus; Wurz, Stefan; Haas, Cornelia; Frühauf, Sabine; Fuchs, Werner
2015-01-01
BACKGROUND Lactic acid is an important biorefinery platform chemical. The use of thermophilic amylolytic microorganisms to produce lactic acid by fermentation constitutes an efficient strategy to reduce operating costs, including raw materials and sterilization costs. RESULTS A process for the thermophilic production of lactic acid by Geobacillus stearothermophilus directly from potato starch was characterized and optimized. Geobacillus stearothermophilus DSM 494 was selected out of 12 strains screened for amylolytic activity and the ability to form lactic acid as the major product of the anaerobic metabolism. In total more than 30 batches at 3–l scale were run at 60 °C under non-sterile conditions. The process developed produced 37 g L−1 optically pure (98%) L-lactic acid in 20 h from 50 g L−1 raw potato starch. As co-metabolites smaller amounts (<7% w/v) of acetate, formate and ethanol were formed. Yields of lactic acid increased from 66% to 81% when potato residues from food processing were used as a starchy substrate in place of raw potato starch. CONCLUSIONS Potato starch and residues were successfully converted to lactic acid by G. stearothermophilus. The process described in this study provides major benefits in industrial applications and for the valorization of starch-rich waste streams. © 2015 The Authors.Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:25937690
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Abdel-Rahman, Mohamed Ali; Tashiro, Yukihiro; Zendo, Takeshi; Sakai, Kenji; Sonomoto, Kenji
2015-01-01
Production of optically pure lactic acid from lignocellulosic material for commercial purposes is hampered by several difficulties, including heterofermentation of pentose sugars and high energy consumption by mesophilic lactic acid bacteria. Here, we report a novel lactic acid bacterium, strain QU 50, that has the potential to produce optically pure l-lactic acid (≥99.2%) in a homofermentative manner from xylose under thermophilic conditions. Strain QU 50 was isolated from Egyptian fertile soil and identified as Enterococcus faecium QU 50 by analyzing its sugar fermentation pattern and 16S rRNA gene sequence. Enterococcus faecium QU 50 fermented xylose efficiently to produce lactic acid over wide pH (6.0-10.0) and temperature ranges (30-52°C), with a pH of 6.5 and temperature of 50°C being optimal. To our knowledge, this is the first report of homofermentative lactic acid production from xylose by a thermophilic lactic acid bacterium. © FEMS 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Coelho, Luciana Fontes; Beitel, Susan Michelz; Sass, Daiane Cristina; Neto, Paulo Marcelo Avila; Contiero, Jonas
2018-04-01
Bacillus coagulans arr4 is a thermotolerant microorganism with great biotechnological potential for l-(+)-lactic acid production from granulated sugar and yeast extract. The highest l-(+)-lactic acid production was obtained with Ca(OH) 2 . The maximum production of l-(+)-lactic acid (206.81 g/L) was observed in exponential feeding using granulated sugar solution (900 g/L) and yeast extract (1%) at 50 °C, pH 6.5, and initial granulated sugar concentration of 100 g/L at 39 h. 5.3 g/L h productivity and 97% yield were observed, and no sugar remained. Comparing the simple batch with exponential fed-batch fermentation, the l(+) lactic acid production was improved in 133.22% and dry cell weight was improved in 83.29%, using granulated sugar and yeast extract. This study presents the highest productivity of lactic acid ever observed in the literature, on the fermentation of thermotolerant Bacillus sp. as well as an innovative and high-efficiency purification technology, using low-cost substances as Celite and charcoal. The recovery of lactic acid was 86%, with 100% protein removal, and the fermentation medium (brown color) became a colorless solution.
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Microbe participation in aroma production during soy sauce fermentation.
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.
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de Lima, Pollyne Borborema Almeida; Mulder, Kelly Cristina Leite; Melo, Nadiele Tamires Moreira; Carvalho, Lucas Silva; Menino, Gisele Soares; Mulinari, Eduardo; de Castro, Virgilio H; Dos Reis, Thaila F; Goldman, Gustavo Henrique; Magalhães, Beatriz Simas; Parachin, Nádia Skorupa
2016-09-15
Crude glycerol is the main byproduct of the biodiesel industry. Although it can have different applications, its purification is costly. Therefore, in this study a biotechnological route has been proposed for further utilization of crude glycerol in the fermentative production of lactic acid. This acid is largely utilized in food, pharmaceutical, textile, and chemical industries, making it the hydroxycarboxylic acid with the highest market potential worldwide. Currently, industrial production of lactic acid is done mainly using sugar as the substrate. Thus here, for the first time, Pichia pastoris has been engineered for heterologous L-lactic acid production using glycerol as a single carbon source. For that, the Bos taurus lactate dehydrogenase gene was introduced into P. pastoris. Moreover, a heterologous and a novel homologous lactate transporter have been evaluated for L-lactic acid production. Batch fermentation of the P. pastoris X-33 strain producing LDHb allowed for lactic acid production in this yeast. Although P. pastoris is known for its respiratory metabolism, batch fermentations were performed with different oxygenation levels, indicating that lower oxygen availability increased lactic acid production by 20 %, pushing the yeast towards a fermentative metabolism. Furthermore, a newly putative lactate transporter from P. pastoris named PAS has been identified by search similarity with the lactate transporter from Saccharomyces cerevisiae Jen1p. Both heterologous and homologous transporters, Jen1p and PAS, were evaluated in one strain already containing LDH activity. Fed-batch experiments of P. pastoris strains carrying the lactate transporter were performed with the batch phase at aerobic conditions followed by an aerobic oxygen-limited phase where production of lactic acid was favored. The results showed that the strain containing PAS presented the highest lactic acid titer, reaching a yield of approximately 0.7 g/g. We showed that P. pastoris has a great potential as a fermentative organism for producing L-lactic acid using glycerol as the carbon source at limited oxygenation conditions (below 0.05 % DO in the bioreactor). The best strain had both the LDHb and the homologous lactate transporter encoding genes expressed, and reached a titer 1.5 times higher than the strain with the S. cerevisiae transporter. Finally, it was also shown that increased lactic acid production was concomitant to reduction of acetic acid formation by half.
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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.
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Neu, Anna-Katrin; Pleissner, Daniel; Mehlmann, Kerstin; Schneider, Roland; Puerta-Quintero, Gloria Inés; Venus, Joachim
2016-07-01
In this study, mucilage, a residue from coffee production, was investigated as substrate in fermentative l(+)-lactic acid production. Mucilage was provided as liquid suspension consisting glucose, galactose, fructose, xylose and sucrose as free sugars (up to 60gL(-1)), and used directly as medium in Bacillus coagulans batch fermentations carried out at 2 and 50L scales. Using mucilage and 5gL(-1) yeast extract as additional nitrogen source, more than 40gL(-1) lactic acid was obtained. Productivity and yield were 4-5gL(-1)h(-1) and 0.70-0.77g lactic acid per g of free sugars, respectively, irrespective the scale. Similar yield was found when no yeast extract was supplied, the productivity, however, was 1.5gL(-1)h(-1). Down-stream processing of culture broth, including filtration, electrodialysis, ion exchange chromatography and distillation, resulted in a pure lactic acid formulation containing 930gL(-1)l(+)-lactic acid. Optical purity was 99.8%. Copyright © 2016 Elsevier Ltd. All rights reserved.
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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.
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Liuyun, Jiang; Lixin, Jiang; Chengdong, Xiong; Lijuan, Xu; Ye, Li
2016-01-01
It is promising and challenging to study surface modification for nano-hydroxyapatite to improve the dispersion and enhance the mechanical properties and bioactivity of poly(lactic acid-co-glycolic acid). In this paper, we designed an effective new surface grafting with the assist of l-lysine for nano-hydroxyapatite, and the nano-hydroxyapatite surface grafted with the assist of l-lysine (g-nano-hydroxyapatite) was incorporated into poly(lactic acid-co-glycolic acid) to develop a series of g-nano-hydroxyapatite/poly(lactic acid-co-glycolic acid) nano-composites. The surface modification reaction for nano-hydroxyapatite, the mechanical properties, and in vitro human osteoblast-like cell (MG-63) response were characterized and investigated by Fourier transformation infrared, thermal gravimetric analysis, dispersion test, electromechanical universal tester, differential scanning calorimeter measurements, and in vitro cells culture experiment. The results showed that the grafting amount on the surface of nano-hydroxyapatite was enhanced with the increase of l-lysine, and the dispersion of nano-hydroxyapatite was improved more, so that it brought about better promotion crystallization and more excellent mechanical enhancement effect for poly(lactic acid-co-glycolic acid), comparing with the unmodified nano-hydroxyapatite. Moreover, the cells' attachment and proliferation results confirmed that the incorporation of the g-nano-hydroxyapatite into poly(lactic acid-co-glycolic acid) exhibited better biocompatibility than poly(lactic acid-co-glycolic acid). The above results indicated that the new surface grafting with the assist of l-lysine for nano-hydroxyapatite was an ideal novel surface modification method, which brought about better mechanical enhancement effect and in vitro bioactivity for poly(lactic acid-co-glycolic acid) with adding higher g-nano-hydroxyapatite content, suggesting it had a great potential to be used as bone fracture internal fixation materials in future. © The Author(s) 2015.
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NASA Astrophysics Data System (ADS)
Zhu, Yongming; Lee, Y. Y.; Elander, Richard T.
Treatment of corn stover with aqueous ammonia removes most of the structural lignin, whereas retaining the majority of the carbohydrates in the solids. After treatment, both the cellulose and hemicellulose in corn stover become highly susceptible to enzymatic digestion. In this study, corn stover treated by aqueous ammonia was investigated as the substrate for lactic acid production by simultaneous saccharification and cofermentation (SSCF). A commercial cellulase (Spezyme-CP) and Lactobacillus pentosus American Type Culture Collection (ATCC) 8041 (Spanish Type Culture Collection [CECT]-4023) were used for hydrolysis and fermentation, respectively. In batch SSCF operation, the carbohydrates in the treated corn stover were converted to lactic acid with high yields, the maximum lactic acid yield reaching 92% of the stoichiometric maximum based on total fermentable carbohydrates (glucose, xylose, and arabinose). A small amount of acetic acid was also produced from pentoses through the phosphoketolase pathway. Among the major process variables for batch SSCF, enzyme loading and the amount of yeast extract were found to be the key factors affecting lactic acid production. Further tests on nutrients indicated that corn steep liquor could be substituted for yeast extract as a nitrogen source to achieve the same lactic acid yield. Fed-batch operation of the SSCF was beneficial in raising the concentration of lactic acid to a maximum value of 75.0 g/L.
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Recent advances in lactic acid production by microbial fermentation processes.
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.
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NASA Astrophysics Data System (ADS)
Li, Wen; Wang, Tao; Yang, Yingge; Liu, Dan; Fan, Yonghong; Wang, Dongmei; Yang, Qian; Yao, Jianming; Zheng, Zhiming; Yu, Zengliang
2008-04-01
In order to get an industrial strain which can yield a high concentration of lactic acid for ISPR (in situ product removal), the original strain Rhizopus oryzae RE3303 was mutated by low-energy ion beam implantation. A mutant RK02 was screened, and the factors such as the substrate concentration, nitrogen source concentration, inoculum size, seed age, aeration and temperature that affect the production of lactic acid were studied in detail. Under optimal conditions, the maximum concentration of L(+)-lactic acid reached 34.85 g/L after 30 h shake-flask cultivation without adding any neutralisation (5% Glucose added), which was a 146% increase in lactic acid production after ion implantation compared with the original strain. It was also shown that RK02 can be used in ISPR to reduce the number of times of separation.
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Ma, Kedong; Hu, Guoquan; Pan, Liwei; Wang, Zichao; Zhou, Yi; Wang, Yanwei; Ruan, Zhiyong; He, Mingxiong
2016-11-01
A thermophilic strain Bacillus coagulans (NBRC 12714) was employed to produce l-lactic acid from corn stover hydrolysate in membrane integrated continuous fermentation. The strain NBRC 12714 metabolized glucose and xylose by the Embden-Meyerhof-Parnas pathway (EMP) and the pentose phosphate pathway (PPP), producing l-lactic acid with optical purity >99.5%. The overall l-lactic acid titer of 92g/l with a yield of 0.91g/g and a productivity of 13.8g/l/h were achieved at a dilution rate of 0.15h(-1). The productivity obtained was 1.6-fold than that of conventional continuous fermentation without cell recycling, and also was the highest among the relevant studies ever reported. These results indicated that the process developed had great potential for economical industrial production of l-lactic acid from lignocellulosic biomass. Copyright © 2016 Elsevier Ltd. All rights reserved.
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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.
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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.
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Hama, Shinji; Mizuno, Shino; Kihara, Maki; Tanaka, Tsutomu; Ogino, Chiaki; Noda, Hideo; Kondo, Akihiko
2015-01-01
This study focused on the process development for the d-lactic acid production from cellulosic feedstocks using the Lactobacillus plantarum mutant, genetically modified to produce optically pure d-lactic acid from both glucose and xylose. The simultaneous saccharification and fermentation (SSF) using delignified hardwood pulp (5-15% loads) resulted in the lactic acid titers of 55.2-84.6g/L after 72h and increased productivities of 1.77-2.61g/L/h. To facilitate the enzymatic saccharification of high-load pulp at a fermentation temperature, short-term (⩽10min) pulverization of pulp was conducted, leading to a significantly improved saccharification with the suppressed formation of formic acid by-product. The short-term milling followed by SSF resulted in a lactic acid titer of 102.3g/L, an optical purity of 99.2%, and a yield of 0.879g/g-sugars without fed-batch process control. Therefore, the process presented here shows promise for the production of high-titer d-lactic acid using the L. plantarum mutant. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Félix Lanao, Rosa P.; Jonker, Anika M.; Wolke, Joop G.C.; Jansen, John A.; van Hest, Jan C.M.
2013-01-01
Poly(lactic-co-glycolic acid) (PLGA) is the most often used synthetic polymer within the field of bone regeneration owing to its biocompatibility and biodegradability. As a consequence, a large number of medical devices comprising PLGA have been approved for clinical use in humans by the American Food and Drug Administration. As compared with the homopolymers of lactic acid poly(lactic acid) and poly(glycolic acid), the co-polymer PLGA is much more versatile with regard to the control over degradation rate. As a material for bone regeneration, the use of PLGA has been extensively studied for application and is included as either scaffolds, coatings, fibers, or micro- and nanospheres to meet various clinical requirements. PMID:23350707
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Tashiro, Yukihiro; Matsumoto, Hiroko; Miyamoto, Hirokuni; Okugawa, Yuki; Pramod, Poudel; Miyamoto, Hisashi; Sakai, Kenji
2013-10-01
We investigated L-lactic acid production in static batch fermentation of kitchen refuse using a bacterial consortium from marine-animal-resource (MAR) composts at temperatures ranging from 30 to 65 °C. At relatively low temperatures butyric acid accumulated, whereas at higher temperatures L-lactic acid was produced. In particular, fermentation at 50 °C produced 34.5 g L(-1) L-lactic acid with 90% lactic acid selectivity and 100% optical purity. Denaturing gradient gel electrophoresis indicated that dominant bacteria present in the original MAR composts diminished rapidly and Bacillus coagulans strains became the dominant contributors to L-lactic acid production at 45, 50 and 55 °C. This is the first report of the achievement of 100% optical purity of L-lactic acid using a bacterial consortium. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Sugiyama, Minetaka; Akase, Shin-Pei; Nakanishi, Ryota; Horie, Hitoshi; Kaneko, Yoshinobu
2014-01-01
Improvement of the lactic acid resistance of the yeast Saccharomyces cerevisiae is important for the application of the yeast in industrial production of lactic acid from renewable resources. However, we still do not know the precise mechanisms of the lactic acid adaptation response in yeast and, consequently, lack effective approaches for improving its lactic acid tolerance. To enhance our understanding of the adaptation response, we screened for S. cerevisiae genes that confer enhanced lactic acid resistance when present in multiple copies and identified the transcriptional factor Haa1 as conferring resistance to toxic levels of lactic acid when overexpressed. The enhanced tolerance probably results from increased expression of its target genes. When cells that expressed Haa1 only from the endogenous promoter were exposed to lactic acid stress, the main subcellular localization of Haa1 changed from the cytoplasm to the nucleus within 5 min. This nuclear accumulation induced upregulation of the Haa1 target genes YGP1, GPG1, and SPI1, while the degree of Haa1 phosphorylation observed under lactic acid-free conditions decreased. Disruption of the exportin gene MSN5 led to accumulation of Haa1 in the nucleus even when no lactic acid was present. Since Msn5 was reported to interact with Haa1 and preferentially exports phosphorylated cargo proteins, our results suggest that regulation of the subcellular localization of Haa1, together with alteration of its phosphorylation status, mediates the adaptation to lactic acid stress in yeast. PMID:24682296
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van der Pol, Edwin C; Eggink, Gerrit; Weusthuis, Ruud A
2016-01-01
Sugars derived from lignocellulose-rich sugarcane bagasse can be used as feedstock for production of l(+)-lactic acid, a precursor for renewable bioplastics. In our research, acid-pretreated bagasse was hydrolysed with the enzyme cocktail GC220 and fermented by the moderate thermophilic bacterium Bacillus coagulans DSM2314. Saccharification and fermentation were performed simultaneously (SSF), adding acid-pretreated bagasse either in one batch or in two stages. SSF was performed at low enzyme dosages of 10.5-15.8 FPU/g DW bagasse. The first batch SSF resulted in an average productivity of 0.78 g/l/h, which is not sufficient to compete with lactic acid production processes using high-grade sugars. Addition of 1 g/l furfural to precultures can increase B. coagulans resistance towards by-products present in pretreated lignocellulose. Using furfural-containing precultures, productivity increased to 0.92 g/l/h, with a total lactic acid production of 91.7 g in a 1-l reactor containing 20% W/W DW bagasse. To increase sugar concentrations, bagasse was solubilized with a liquid fraction, obtained directly after acid pretreatment. Solubilizing the bagasse fibres with water increased the average productivity to 1.14 g/l/h, with a total lactic acid production of 84.2 g in a 1-l reactor. Addition of bagasse in two stages reduced viscosity during SSF, resulting in an average productivity in the first 23 h of 2.54 g/l/h, similar to productivities obtained in fermentations using high-grade sugars. Due to fast accumulation of lactic acid, enzyme activity was repressed during two-stage SSF, resulting in a decrease in productivity and a slightly lower total lactic acid production of 75.6 g. In this study, it is shown that an adequate production of lactic acid from lignocellulose was successfully accomplished by a two-stage SSF process, which combines acid-pretreated bagasse, B. coagulans precultivated in the presence of furfural as microorganism, and GC220 as enzyme cocktail. The process may be further improved by enhancing enzyme hydrolysis activities at high lactic acid concentrations.
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Topical zinc oxide vs. salicylic acid-lactic acid combination in the treatment of warts.
Khattar, Joe A; Musharrafieh, Umayya M; Tamim, Hala; Hamadeh, Ghassan N
2007-04-01
Warts are a common dermatologic problem. Treatment is painful, prolonged, and can cause scarring. To evaluate topical zinc oxide for the treatment of warts. This was a randomized, double-blind controlled trial of 44 patients. Twenty-two patients were given topical zinc oxide 20% ointment, and the other 22 received salicylic acid 15% + lactic acid 15% ointment twice daily. All patients were followed up for 3 months or until cure, whichever occurred first. All patients were observed for side-effects. Sixteen patients in the zinc group and 19 in the salicylic acid-lactic acid group completed the study. In the zinc oxide-treated group, 50% of the patients showed complete cure and 18.7% failed to respond, compared with 42% and 26%, respectively, in the salicylic acid-lactic acid-treated group. No patients developed serious side-effects. Topical zinc oxide is an efficacious, painless, and safe therapeutic option for wart treatment.
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Verstraelen, Hans; Vervaet, Chris; Remon, Jean-Paul
2016-01-01
Bacterial vaginosis is a prevalent state of dysbiosis of the vaginal microbiota with wide-ranging impact on human reproductive health. Based on recent insights in community ecology of the vaginal microbiome, we hypothesize that sustained vaginal DL-lactic acid enrichment will enhance the recruitment of lactobacilli, while counteracting bacterial vaginosis-associated bacteria. We therefore aimed to develop an intravaginal device that would be easy to insert and remove, while providing sustained DL-lactic acid release into the vaginal lumen. The final prototype selected is a vaginal ring matrix system consisting of a mixture of ethylene vinyl acetate and methacrylic acid-methyl methacrylate copolymer loaded with 150 mg DL-lactic acid with an L/D-lactic acid ratio of 1:1. Preclinical safety assessment was performed by use of the Slug Mucosal Irritation test, a non-vertebrate assay to evaluate vaginal mucosal irritation, which revealed no irritation. Clinical safety was evaluated in a phase I trial with six healthy nulliparous premenopausal volunteering women, with the investigational drug left in place for 7 days. Colposcopic monitoring according to the WHO/CONRAD guidelines for the evaluation of vaginal products, revealed no visible cervicovaginal mucosal changes. No adverse events related to the investigational product occurred. Total release from the intravaginal ring over 7 days was estimated through high performance liquid chromatography at 37.1 (standard deviation 0.9) mg DL-lactic acid. Semisolid lactic acid formulations have been studied to a limited extent in the past and typically consist of a large volume of excipients and very high doses of lactic acid, which is of major concern to mucosal safety. We have documented the feasability of enriching the vaginal environment with pure DL-lactic acid with a prototype intravaginal ring. Though the efficacy of this platform remains to be established possibly requiring further development, this approach may offer a novel avenue to modulate and protect the vaginal microbiota.
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Low-pH production of D-lactic acid using newly isolated acid tolerant yeast Pichia kudriavzevii NG7.
Park, Hyun Joo; Bae, Jung-Hoon; Ko, Hyeok-Jin; Lee, Sun-Hee; Sung, Bong Hyun; Han, Jong-In; Sohn, Jung-Hoon
2018-06-13
Lactic acid is a platform chemical for the sustainable production of various materials. To develop a robust yeast platform for low-pH production of D-lactic acid, an acid-tolerant yeast strain was isolated from grape skins and named Pichia kudriavzevii NG7 by ribosomal RNA sequencing. This strain was able to grow at pH 2.0 and 50°C. For the commercial application of P. kudriavzevii NG7 as a lactic acid producer, the ethanol fermentation pathway was redirected to lactic acid by replacing pyruvate decarboxylase 1 gene (PDC1) with D-lactate dehydrogenase gene (D-LDH) derived from Lactobacillus plantarum. To enhance lactic acid tolerance, this engineered strain was adapted to high lactic acid concentrations, and a new transcriptional regulator, PAR1, responsible for acid tolerance, was identified by whole-genome resequencing. The final engineered strain produced 135 g/L and 154 g/L of D-lactic acid with productivity over 3.66 g/L/h at pH 3.6 and 4.16 g/L/h at pH 4.7, respectively. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
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21 CFR 582.1061 - Lactic acid.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Lactic acid. 582.1061 Section 582.1061 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1061 Lactic acid. (a) Product. Lactic acid. (b) Conditions of use. This substance is generally...
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21 CFR 582.1061 - Lactic acid.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Lactic acid. 582.1061 Section 582.1061 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1061 Lactic acid. (a) Product. Lactic acid. (b) Conditions of use. This substance is generally...
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21 CFR 582.1061 - Lactic acid.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Lactic acid. 582.1061 Section 582.1061 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1061 Lactic acid. (a) Product. Lactic acid. (b) Conditions of use. This substance is generally...
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21 CFR 582.1061 - Lactic acid.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Lactic acid. 582.1061 Section 582.1061 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1061 Lactic acid. (a) Product. Lactic acid. (b) Conditions of use. This substance is generally...
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Venkatesh, P M; Sen, A
2017-12-01
Attraction of Aedes aegypti to various binary, trinary, and quaternary blends of lactic acid and ketones with or without ammonia was studied using a dual choice olfactometer. A dose dependent attraction was observed in cases of single compounds where cyclopentanone attracted the highest percentage (36.9 ± 1.8%) of Ae. aegypti when tested alone. No significant difference was observed between the attraction levels of trinary and binary blends of lactic acid and acetone or butanone when tested against clear air. However, in competitive bioassays, the trinary blend of lactic acid, acetone, and butanone was significantly preferred over binary blends of individual compounds ( P < 0.05). Acetylacetone was weakly attractive when tested alone but showed additive attraction when blended with lactic acid. However, acetylacetone acted as an attraction inhibitor when blended with other compounds. Cyclopentanone was attractive, but enhancement of attraction was not observed when blended with other components. Addition of ammonia to binary or trinary blends of lactic acid, acetone, and/or butanone did not increase the attraction significantly. In competitive bioassays, the blends containing ammonia were significantly preferred over the blends lacking ammonia ( P < 0.05). This highlights ammonia as an essential component of synthetic blends. A quaternary blend of lactic acid, ammonia, acetone, and butanone was most attractive (65 ± 1.5%) and preferred blend of all other combinations.
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2013-01-01
Background Efficient conversion of lignocellulosic biomass to optically pure lactic acid is a key challenge for the economical production of biodegradable poly-lactic acid. A recently isolated strain, Thermoanaerobacterium aotearoense SCUT27, is promising as an efficient lactic acid production bacterium from biomass due to its broad substrate specificity. Additionally, its strictly anaerobic and thermophilic characteristics suppress contamination from other microoragnisms. Herein, we report the significant improvements of concentration and yield in lactic acid production from various lignocellulosic derived sugars, achieved by the carbon flux redirection through homologous recombination in T. aotearoense SCUT27. Results T. aotearoense SCUT27 was engineered to block the acetic acid formation pathway to improve the lactic acid production. The genetic manipulation resulted in 1.8 and 2.1 fold increase of the lactic acid yield using 10 g/L of glucose or 10 g/L of xylose as substrate, respectively. The maximum l-lactic acid yield of 0.93 g/g glucose with an optical purity of 99.3% was obtained by the engineered strain, designated as LA1002, from 50 g/L of substrate, which is very close to the theoretical value (1.0 g/g of glucose). In particular, LA1002 produced lactic acid at an unprecedented concentration up to 3.20 g/L using 10 g/L xylan as the single substrate without any pretreatment after 48 h fermentation. The non-sterilized fermentative production of l-lactic acid was also carried out, achieving values of 44.89 g/L and 0.89 g/g mixed sugar for lactic acid concentration and yield, respectively. Conclusions Blocking acetic acid formation pathway in T. aotearoense SCUT27 increased l-lactic acid production and yield dramatically. To our best knowledge, this is the best performance of fermentation on lactic acid production using xylan as the sole carbon source, considering the final concentration, yield and fermentation time. In addition, it should be mentioned that the performance of non-sterilized simultaneous fermentation from glucose and xylose was very close to that of normal sterilized cultivation. All these results used the mutant strain, LA1002, indicated that it is a new promising candidate for the effective production of optically pure l-lactic acid from lignocellulosic biomass. PMID:23985133
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Xue, Gang; Lai, Sizhou; Li, Xiang; Zhang, Wenjuan; You, Jiguang; Chen, Hong; Qian, Yajie; Gao, Pin; Liu, Zhenhong; Liu, Yanan
2017-12-12
Lactic acid is one of the emerging top biomass derived platform chemicals that can be fermented from organic wastes. This study evaluated the potential of Cathodic Electro-Fermentation (CEF) as a novel approach to enhance the yield of high optical activity (OA) of l-lactic acid from organic wastes using mixed microbial consortium. The fermentation process was stimulated through the cathode applied with -100 mV versus standard hydrogen electrode (SHE), which contributed to 4.73 times higher lactic acid productivity (0.6578 g L -1 h -1 ) compared to that in the open circuit control (0.1392 g L -1 h -1 ), and an improved OA of l-lactic acid was also observed (42.3% vs. 3.6% of the open circuit control). The study elucidated that the optimal voltage at -100 mV promoted the conversion of pyruvate to l-lactate by 77.9% compared to the Blank, which triggered the generation of l-lactic acid to occur rapidly even at low concentration of pyruvate. The significant variation of microbial community in family- and genus-level distributions were observed in CEF system. Furthermore, the open-circuit operation test demonstrated that the cathode providing in-situ electron supply was essential to achieve high efficient bioconversion of organic wastes to lactic acid. Our work highlights the feasibility of CEF to steer high value-added fermentation products deriving from organic wastes by the mixed microbial consortium. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Lactic acid fermentation in the production of foods from vegetables, cereals and legumes.
Steinkraus, K H
1983-09-01
Lactic acid bacteria perform an essential role in the preservation and production of wholesome foods. Generally the lactic acid fermentations are low-cost and often little or no heat is required in their preparation. Thus, they are fuel-efficient. Lactic acid fermented foods have an important role in feeding the world's population on every continent today. As world population rises, lactic acid fermentation is expected to become even more important in preserving fresh vegetables, fruits, cereals and legumes for feeding humanity.
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Johanningsmeier, Suzanne D; Franco, Wendy; Perez-Diaz, Ilenys; McFeeters, Roger F
2012-07-01
Cucumbers are preserved commercially by natural fermentations in 5% to 8% sodium chloride (NaCl) brines. Occasionally, fermented cucumbers spoil after the primary fermentation is complete. This spoilage has been characterized by decreases in lactic acid and a rise in brine pH caused by microbial instability. Objectives of this study were to determine the combined effects of NaCl and pH on fermented cucumber spoilage and to determine the ability of lactic acid bacteria (LAB) spoilage isolates to initiate lactic acid degradation in fermented cucumbers. Cucumbers fermented with 0%, 2%, 4%, and 6% NaCl were blended into slurries (FCS) and adjusted to pH 3.2, 3.8, 4.3, and 5.0 prior to centrifugation, sterile-filtration, and inoculation with spoilage organisms. Organic acids and pH were measured initially and after 3 wk, 2, 6, 12, and 18 mo anaerobic incubation at 25 °C. Anaerobic lactic acid degradation occurred in FCS at pH 3.8, 4.3, and 5.0 regardless of NaCl concentration. At pH 3.2, reduced NaCl concentrations resulted in increased susceptibility to spoilage, indicating that the pH limit for lactic acid utilization in reduced NaCl fermented cucumbers is 3.2 or lower. Over 18 mo incubation, only cucumbers fermented with 6% NaCl to pH 3.2 prevented anaerobic lactic acid degradation by spoilage bacteria. Among several LAB species isolated from fermented cucumber spoilage, Lactobacillus buchneri was unique in its ability to metabolize lactic acid in FCS with concurrent increases in acetic acid and 1,2-propanediol. Therefore, L. buchneri may be one of multiple organisms that contribute to development of fermented cucumber spoilage. Microbial spoilage of fermented cucumbers during bulk storage causes economic losses for producers. Current knowledge is insufficient to predict or control these losses. This study demonstrated that in the absence of oxygen, cucumbers fermented with 6% sodium chloride to pH 3.2 were not subject to spoilage. However, lactic acid was degraded by spoilage microorganisms in reduced salt, even with pH as low as 3.2. Efforts to reduce salt in commercial brining operations will need to include control measures for this increased susceptibility to spoilage. Lactobacillus buchneri was identified as a potential causative agent and could be used as a target in development of such control measures. Journal of Food Science © 2012 Institute of Food Technologists® No claim to original US government works.
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21 CFR 184.1061 - Lactic acid.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Lactic acid. 184.1061 Section 184.1061 Food and... Substances Affirmed as GRAS § 184.1061 Lactic acid. (a) Lactic acid (C3H6O3, CAS Reg. Nos.: dl mixture, 598-82-3; l-isomer, 79-33-4; d-isomer, 10326-41-7), the chemical 2-hydroxypropanoic acid, occurs...
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Code of Federal Regulations, 2013 CFR
2013-07-01
..., carrier Lactic acid Solvent Lactic acid, 2-ethylhexyl ester (CAS Reg. No. 6283-86-9) Solvent Lactic acid, 2-ethylhexyl ester, (2S)- (CAS Reg. No. 186817-80-1) Solvent Lactic acid, n-propyl ester, (S); (CAS... agent Thiosulfuric acid, disodium salt, pentahydrate. (CAS Reg. No. 10102-17-7) Do. d-Alpha tocopherol...
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Code of Federal Regulations, 2012 CFR
2012-07-01
..., carrier Lactic acid Solvent Lactic acid, 2-ethylhexyl ester (CAS Reg. No. 6283-86-9) Solvent Lactic acid, 2-ethylhexyl ester, (2S)- (CAS Reg. No. 186817-80-1) Solvent Lactic acid, n-propyl ester, (S); (CAS... coating agent Petroleum wax, conforming to 21 CFR 172.886(d) Coating agent Phosphoric acid Buffer...
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21 CFR 184.1061 - Lactic acid.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Lactic acid. 184.1061 Section 184.1061 Food and... Substances Affirmed as GRAS § 184.1061 Lactic acid. (a) Lactic acid (C3H6O3, CAS Reg. Nos.: dl mixture, 598-82-3; l-isomer, 79-33-4; d-isomer, 10326-41-7), the chemical 2-hydroxypropanoic acid, occurs...
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Patel, J C; Sawant, M S; Amin, B M
2000-01-01
1. The level of lactic acid was found to be 25 mg percent in 95 percent of 186 normal Indians. There was no difference due to sex and age. 2. Level of lactic acid was estimated in blood of normal persons and diabetics Type II patients to observe the effects of food and glucose. There was no change except the level of lactic acid was in higher but in normal range. 3. Hyperglycemia of over 300 mg raised the blood lactic acid in 25 percent of patients. 4. Lactic acid was not affected by hypercholesteremia but was raised in 60 percent of cases with raised blood urea. 5. Lactic acid was found to remain within normal limits in 48 type II diabetics treated with phenformin dose varying from 50 mg to 225 mg per day. The duration of treatment varied from one year to seven years.
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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.
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Thapa, Laxmi Prasad; Lee, Sang Jun; Park, Chulhwan; Kim, Seung Wook
2017-07-01
In this study, L-lactic acid production was investigated from metabolically engineered strain of E. aerogenes ATCC 29007. The engineered strain E. aerogenes SUMI01 (Δpta) was generated by the deletion of phosphate acetyltransferase (pta) gene from the chromosome of E. aerogenes ATCC 29007 and deletion was confirmed by colony PCR. Under the optimized fermentation conditions, at 37°C and pH 6 for 84h, the L-lactic acid produced by engineered strain E. aerogenes SUMI01 (Δpta) in flask fermentation using 100g/L mannitol as the carbon source was 40.05g/L as compared to that of the wild type counterpart 20.70g/L. At the end of the batch fermentation in bioreactor the production of L-lactic acid reached to 46.02g/L and yield was 0.41g/g by utilizing 112.32g/L mannitol. This is the first report regarding the production of L-lactic acid from Enterobacter species. We believe that this result may provide valuable guidelines for further engineering Enterobacter strain for the improvement of L-lactic acid production. Copyright © 2017 Elsevier Inc. All rights reserved.
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Microbial production of lactic acid: the latest development.
Juturu, Veeresh; Wu, Jin Chuan
2016-12-01
Lactic acid is an important platform chemical for producing polylactic acid (PLA) and other value-added products. It is naturally produced by a wide spectrum of microbes including bacteria, yeast and filamentous fungi. In general, bacteria ferment C5 and C6 sugars to lactic acid by either homo- or hetero-fermentative mode. Xylose isomerase, phosphoketolase, transaldolase, l- and d-lactate dehydrogenases are the key enzymes that affect the ways of lactic acid production. Metabolic engineering of microbial strains are usually needed to produce lactic acid from unconventional carbon sources. Production of d-LA has attracted much attention due to the demand for producing thermostable PLA, but large scale production of d-LA has not yet been commercialized. Thermophilic Bacillus coagulans strains are able to produce l-lactic acid from lignocellulose sugars homo-fermentatively under non-sterilized conditions, but the lack of genetic tools for metabolically engineering them severely affects their development for industrial applications. Pre-treatment of agriculture biomass to obtain fermentable sugars is a pre-requisite for utilization of the huge amounts of agricultural biomass to produce lactic acid. The major challenge is to obtain quality sugars of high concentrations in a cost effective-way. To avoid or minimize the use of neutralizing agents during fermentation, genetically engineering the strains to make them resist acidic environment and produce lactic acid at low pH would be very helpful for reducing the production cost of lactic acid.
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Improvement of lactic acid production in Saccharomyces cerevisiae by a deletion of ssb1.
Lee, Jinsuk J; Crook, Nathan; Sun, Jie; Alper, Hal S
2016-01-01
Polylactic acid (PLA) is an important renewable polymer, but current processes for producing its precursor, lactic acid, suffer from process inefficiencies related to the use of bacterial hosts. Therefore, improving the capacity of Saccharomyces cerevisiae to produce lactic acid is a promising approach to improve industrial production of lactic acid. As one such improvement required, the lactic acid tolerance of yeast must be significantly increased. To enable improved tolerance, we employed an RNAi-mediated genome-wide expression knockdown approach as a means to rapidly identify potential genetic targets. In this approach, several gene knockdown targets were identified which confer increased acid tolerance to S. cerevisiae BY4741, of which knockdown of the ribosome-associated chaperone SSB1 conferred the highest increase (52%). This target was then transferred into a lactic acid-overproducing strain of S. cerevisiae CEN.PK in the form of a knockout and the resulting strain demonstrated up to 33% increased cell growth, 58% increased glucose consumption, and 60% increased L-lactic acid production. As SSB1 contains a close functional homolog SSB2 in yeast, this result was counterintuitive and may point to as-yet-undefined functional differences between SSB1 and SSB2 related to lactic acid production. The final strain produced over 50 g/L of lactic acid in under 60 h of fermentation.
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40 CFR 180.1090 - Lactic acid; exemption from the requirement of a tolerance.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Lactic acid; exemption from the requirement of a tolerance. 180.1090 Section 180.1090 Protection of Environment ENVIRONMENTAL PROTECTION... Exemptions From Tolerances § 180.1090 Lactic acid; exemption from the requirement of a tolerance. Lactic acid...
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40 CFR 180.1090 - Lactic acid; exemption from the requirement of a tolerance.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Lactic acid; exemption from the requirement of a tolerance. 180.1090 Section 180.1090 Protection of Environment ENVIRONMENTAL PROTECTION... Exemptions From Tolerances § 180.1090 Lactic acid; exemption from the requirement of a tolerance. Lactic acid...
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40 CFR 180.1090 - Lactic acid; exemption from the requirement of a tolerance.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Lactic acid; exemption from the requirement of a tolerance. 180.1090 Section 180.1090 Protection of Environment ENVIRONMENTAL PROTECTION... Exemptions From Tolerances § 180.1090 Lactic acid; exemption from the requirement of a tolerance. Lactic acid...
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40 CFR 180.1090 - Lactic acid; exemption from the requirement of a tolerance.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Lactic acid; exemption from the requirement of a tolerance. 180.1090 Section 180.1090 Protection of Environment ENVIRONMENTAL PROTECTION... Exemptions From Tolerances § 180.1090 Lactic acid; exemption from the requirement of a tolerance. Lactic acid...
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40 CFR 180.1090 - Lactic acid; exemption from the requirement of a tolerance.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Lactic acid; exemption from the requirement of a tolerance. 180.1090 Section 180.1090 Protection of Environment ENVIRONMENTAL PROTECTION... Exemptions From Tolerances § 180.1090 Lactic acid; exemption from the requirement of a tolerance. Lactic acid...
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Nagasawa, Kazuki; Nagai, Katsuhito; Ishimoto, Atsushi; Fujimoto, Sadaki
2003-08-27
We previously indicated that lovastatin acid, a 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, was transported by a monocarboxylate transporter (MCT) in cultured rat mesangial cells. In this study, to identify the MCT isoform(s) responsible for the lovastatin acid uptake, the transport mechanism was investigated using bovine kidney NBL-1 cells, which have been reported to express only MCT4 at the protein level. On RT-PCR analysis, the message of mRNAs for MCT1 and MCT4 was detected in the NBL-1 cells used in this study, which was confirmed by kinetic analysis of [14C]L-lactic acid uptake, consisting of high- and low-affinity components corresponding to MCT1 and MCT4, respectively. The lovastatin acid uptake depended on an inwardly directed H+-gradient, and was inhibited by representative monocarboxylates, but not by inhibitors/substrates for organic anion transporting polypeptides and organic anion transporters. In addition, L-lactic acid competitively inhibited the uptake of lovastatin acid and lovastatin acid inhibited the low affinity component of [14C]L-lactic acid uptake dose dependently. The inhibition constant of L-lactic acid for lovastatin acid uptake was almost the same as the Michaelis constant for [14C]L-lactic acid uptake by the low-affinity component. These kinetic evidences imply that lovastatin acid was taken up into NBL-1 cells via MCT4.
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Gomółka-Pawlicka, M; Uradziński, J
2003-01-01
The aim of this study was to determine of influence of 15 strains of lactic acid bacteria on the growth of 7 Salmonella spp. strains in model set-ups, and in meat and ripened fermented sausages. The investigations were performed within the framework of three alternate stages which differed in respect to the products studied, the number of Lactobacillus spp. strains and, partly, methodological approach. The ratio between lactic acid bacteria and Salmonella strains studied was, depending on the alternate, 1:1, 1:2 and 2:1, respectively. The investigations also covered the water activity (a(w)) and pH of the tested products. The results obtained are shown in 12 figures and suggest that all the lactic acid bacteria strains used within the framework of the model set-ups showed antagonistic effect on all the Salmonella spp. strains. However, these abilities were not observed with respect to some lactic acid bacteria strains in meat and fermented sausage. The temperature and length of the incubation period of sausages, but not a(w) and pH, were found to have a distinct influence on the antagonistic interaction between the bacteria.
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Djukić-Vuković, Aleksandra P; Mojović, Ljiljana V; Jokić, Bojan M; Nikolić, Svetlana B; Pejin, Jelena D
2013-05-01
In this study, lactic acid and biomass production on liquid distillery stillage from bioethanol production with Lactobacillus rhamnosus ATCC 7469 was studied. The cells were immobilized onto zeolite, a microporous aluminosilicate mineral and the lactic acid production with free and immobilized cells was compared. The immobilization allowed simple cell separation from the fermentation media and their reuse in repeated batch cycles. A number of viable cells of over 10(10) CFU g(-1) of zeolite was achieved at the end of fourth fermentation cycle. A maximal process productivity of 1.69 g L(-1), maximal lactic acid concentration of 42.19 g L(-1) and average yield coefficient of 0.96 g g(-1) were achieved in repeated batch fermentation on the liquid stillage without mineral or nitrogen supplementation. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Isolation of lactic acid bacteria with potential protective culture characteristics from fruits
NASA Astrophysics Data System (ADS)
Hashim, Nurul Huda; Sani, Norrakiah Abdullah
2015-09-01
Lactic acid bacteria are also known as beneficial microorganisms abundantly found in fermented food products. In this study, lactic acid bacteria were isolated from fresh cut fruits obtained from local markets. Throughout the isolation process from 11 samples of fruits, 225 presumptive lactic acid bacteria were isolated on MRS agar medium. After catalase and oxidase tests, 149 resulted to fit the characteristics of lactic acid bacteria. Further identification using Gram staining was conducted to identify the Gram positive bacteria. After this confirmation, the fermentation characteristics of these isolates were identified. It was found that 87 (58.4%) isolates were heterofermentative, while the rest of 62 (41.6%) are homofermentative lactic acid bacteria. Later, all these isolates were investigated for the ability to inhibit growth of Staphylococcus aureus using agar spot assay method. Seven (4.7%) isolates showed strong antagonistic capacity, while 127 (85.2%) and 8 (5.4%) isolates have medium and weak antagonistic capacity, respectively. The other 7 (4.7%) isolates indicated to have no antagonistic effect on S. aureus. Results support the potential of LAB isolated in this study which showed strong antagonistic activity against S. aureus may be manipulated to become protective cultures in food products. While the homofermentative or heterofermentative LAB can be utilized in fermentation of food and non-food products depending on the by-products required during the fermentation.
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Tang, Jialing; Wang, Xiaochang; Hu, Yisong; Zhang, Yongmei; Li, Yuyou
2016-06-01
The effects of pH, temperature and high organic loading rate (OLR) on lactic acid production from food waste without extra inoculum addition were investigated in this study. Using batch experiments, the results showed that although the hydrolysis rate increased with pH adjustment, the lactic acid concentration and productivity were highest at pH 6. High temperatures were suitable for solubilization but seriously restricted the acidification processes. The highest lactic acid yield (0.46g/g-TS) and productivity (278.1mg/Lh) were obtained at 37°C and pH 6. In addition, the lactic acid concentration gradually increased with the increase in OLR, and the semi-continuous reactor could be stably operated at an OLR of 18g-TS/Ld. However, system instability, low lactic acid yield and a decrease in VS removal were noticed at high OLRs (22g-TS/Ld). The concentrations of volatile fatty acids (VFAs) in the fermentation mixture were relatively low but slightly increased with OLR, and acetate was the predominant VFA component. Using high-throughput pyrosequencing, Lactobacillus from the raw food waste was found to selectively accumulate and become dominant in the semi-continuous reactor. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Production of high molecular weight polylactic acid
Bonsignore, Patrick V.
1995-01-01
A degradable high molecular weight poly(lactic acid). A poly(lactic acid) has a terminal end group of one of carboxyl or hydroxyl groups with low molecular weight poly(lactic acid) units coupled with linking agents of di-isocyanates, bis-epoxides, bis-oxazolines and bis-ortho esters. The resulting high molecular weight poly(lactic acid) can be used for applications taking advantage of the improved physical properties.
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Kwaw, Emmanuel; Ma, Yongkun; Tchabo, William; Apaliya, Maurice Tibiru; Wu, Meng; Sackey, Augustina Sackle; Xiao, Lulu; Tahir, Haroon Elrasheid
2018-06-01
This study was conducted to investigate the effect of lactic acid bacteria (LAB) strains on color properties, phenolic profile and antioxidant activities of mulberry juice. Mulberry juice was separately fermented at 37 °C for 36 h using Lactobacillus plantarum, Lactobacillus acidophilus and Lactobacillus paracasei. The results showed that lactic acid fermentation impacted on the color of the juice. Moreover, the study demonstrated that LABs impacted on the phenolic profile of the juice. Syringic acid, cyanidin-3-O-rutinoside and quercetin were the predominant phenolic acid, anthocyanin and flavonol respectively in the lactic-acid-fermented mulberry juice. The degree of radical scavenging activity was species-specific with the L. plantarum fermented juice having the highest radical scavenging activities. The correlation analysis demonstrated that flavonols and anthocyanins were mostly responsible for the increased in 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) scavenging activity while phenolic acids and flavonols were responsible for 2,2-diphenyl-1-picrylhydrazyl scavenging activity and reducing power capacity of the fermented juice. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Comparison of potential risks of lactic acidosis induction by biguanides in rats.
Bando, Kiyoko; Ochiai, Shoko; Kunimatsu, Takeshi; Deguchi, Jiro; Kimura, Juki; Funabashi, Hitoshi; Seki, Takaki
2010-10-01
Lactic acidosis has been considered to be a side effect of some biguanides, after phenformin was withdrawn from the market because of its association with lactic acidosis. The potential of lactic acidosis induced by biguanides at human therapeutic exposure levels, however, has not been examined. Then, we compared the risk of lactic acid at doses providing exposure levels comparable to human therapeutic doses. Metformin and phenformin were orally administered to rats for up to 28 days, and plasma drug concentrations and blood lactic acid levels were examined. Metformin did not elevate lactic acid levels at the dose corresponding to higher systemic drug exposure than human therapeutic level, even for repeated doses. In contrast, phenformin elevated lactic acid levels at the dose corresponding to lower exposure than human therapeutic level, and sustained high levels were observed up to 24h post-dose; furthermore, these changes were enhanced by repeated doses. Direct comparison at each rat equivalent dose clearly indicated that lactic acid levels of phenformin were higher than those of metformin. These non-clinical findings suggest that metformin dose not increase lactic acid levels like phenformin does, and therefore may not increase the risk for lactic acidosis at human therapeutic exposure level. Copyright (c) 2010 Elsevier Inc. All rights reserved.
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Shimizu-Kadota, Mariko; Kato, Hiroaki; Shiwa, Yuh; Oshima, Kenshiro; Machii, Miki; Araya-Kojima, Tomoko; Zendo, Takeshi; Hattori, Masahira; Sonomoto, Kenji; Yoshikawa, Hirofumi
2013-01-01
Lactococcus lactis IO-1 (JCM7638) produces L-lactic acid predominantly when grown at high xylose concentrations, and its utilization is highly desired in the green plastics industry. Therefore it is worthwhile studying its genomic traits. In this study, we focused on (i) genes of possible horizontal transfer derivation (prophages, the nisin-sucrose transposon, and several restriction-modification systems), and (ii) genes for the synthetic pathways of amino acids and vitamins in the IO-1 genome. In view of the results of this analysis, we consider their meanings in strain IO-1.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Goto, Tsuyoshi, E-mail: tgoto@kais.kyoto-u.ac.jp; Research Unit for Physiological Chemistry, The Center for the Promotion of Interdisciplinary Education and Research, Kyoto University; Kim, Young-Il
2015-04-17
Our previous study has shown that gut lactic acid bacteria generate various kinds of fatty acids from polyunsaturated fatty acids such as linoleic acid (LA). In this study, we investigated the effects of LA and LA-derived fatty acids on the activation of peroxisome proliferator-activated receptors (PPARs) which regulate whole-body energy metabolism. None of the fatty acids activated PPARδ, whereas almost all activated PPARα in luciferase assays. Two fatty acids potently activated PPARγ, a master regulator of adipocyte differentiation, with 10-oxo-12(Z)-octadecenoic acid (KetoA) having the most potency. In 3T3-L1 cells, KetoA induced adipocyte differentiation via the activation of PPARγ, and increasedmore » adiponectin production and insulin-stimulated glucose uptake. These findings suggest that fatty acids, including KetoA, generated in gut by lactic acid bacteria may be involved in the regulation of host energy metabolism. - Highlights: • Most LA-derived fatty acids from gut lactic acid bacteria potently activated PPARα. • Among tested fatty acids, KetoA and KetoC significantly activated PPARγ. • KetoA induced adipocyte differentiation via the activation of PPARγ. • KetoA enhanced adiponectin production and glucose uptake during adipogenesis.« less
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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.
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Integrated production of lactic acid and biomass on distillery stillage.
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.
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Heme and menaquinone induced electron transport in lactic acid bacteria.
Brooijmans, Rob; Smit, Bart; Santos, Filipe; van Riel, Jan; de Vos, Willem M; Hugenholtz, Jeroen
2009-05-29
For some lactic acid bacteria higher biomass production as a result of aerobic respiration has been reported upon supplementation with heme and menaquinone. In this report, we have studied a large number of species among lactic acid bacteria for the existence of this trait. Heme- (and menaquinone) stimulated aerobic growth was observed for several species and genera of lactic acid bacteria. These include Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacilllus brevis, Lactobacillus paralimentarius, Streptococcus entericus and Lactococcus garviae. The increased biomass production without further acidification, which are respiration associated traits, are suitable for high-throughput screening as demonstrated by the screening of 8000 Lactococcus lactis insertion mutants. Respiration-negative insertion-mutants were found with noxA, bd-type cytochrome and menaquinol biosynthesis gene-disruptions. Phenotypic screening and in silico genome analysis suggest that respiration can be considered characteristic for certain species. We propose that the cyd-genes were present in the common ancestor of lactic acid bacteria, and that multiple gene-loss events best explains the observed distribution of these genes among the species.
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Mufidah, Elya; Wakayama, Mamoru
2016-12-01
This study investigated the optimization of D-lactic acid production from unutilized biomass, specifically banana peel and corncob by multiple parallel fermentation (MPF) with Leuconostoc mesenteroides and Aspergillus awamori. The factors involved in MPF that were assessed in this study comprised banana peel and corncob, KH 2 PO 4 , Tween 80, MgSO 4 ·7H 2 O, NaCl, yeast extract, and diammonium hydrogen citrate to identify the optimal concentration for D-lactic acid production. Optimization of these component factors was performed using the Taguchi method with an L8 orthogonal array. The optimal concentrations for the effectiveness of MPF using biomass substrates were as follows: (1) banana peel, D-lactic acid production was 31.8 g/L in medium containing 15 % carbon source, 0.5 % KH 2 PO 4 , 0.1 % Tween 80, 0.05 % MgSO 4 ·7H 2 O, 0.05 % NaCl, 1.5 % yeast extract, and 0.2 % diammonium hydrogen citrate. (2) corncob, D-lactic acid production was 38.3 g/L in medium containing 15 % of a carbon source, 0.5 % KH 2 PO 4 , 0.1 % Tween 80, 0.05 % MgSO 4 ·7H 2 O, 0.1 % NaCl, 1.0 % yeast extract, and 0.4 % diammonium hydrogen citrate. Thus, both banana peel and corncob are unutilized potential resources for D-lactic acid production. These results indicate that MPF using L. mesenteroides and A. awamori could constitute part of a potential industrial application of the currently unutilized banana peel and corncob biomass for D-lactic acid production.
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NASA Astrophysics Data System (ADS)
Nurhartadi, E.; Utami, R.; Widowati, E.; Karunawati, B. M.
2018-01-01
Cheese whey is a waste product from cheese processing. It has low solid contents thus required the addition of a thickening agent. Lactic acid bacteria could utilize it in the fermented drink. This research aims to study the effect of taro and lesser yam flour addition as a thickening agent on chemical and sensory characteristics of frozen wheygurt. This research used Complete Randomized Design (CRD) with one factor that is variation ratio of taro and lesser yam flour F1 (4: 0), F2 (3: 1), F3 (2: 2), F4 (1: 3), F5 (0: 4). The number of lactic acid bacteria cell determined by using hemocytometer. The lactic acid content determined by the titrimetric method by using 0.1 N NaOH and phenolphthalein as indicator. pH value measured with pH meter. Sensory characteristics evaluated using hedonic test. The result showed that the addition of taro and lesser yam flour have a significant effect on the number of lactic acid bacteria in frozen wheygurt. The higher lesser yam flour addition, the higher lactic acid bacteria count on frozen wheygurt, due to lesser yam higher glucose and fructo-oligosaccharide content than taro. The higher lesser yam addition, the higher the lactic acid produced. The higher the total bacteria and higher levels of lactic acid, the lower the pH obtained. The conclusion of this study is addition ratio of taro and lesser yam flour effect on the chemical characteristics of frozen wheygurt. There is no difference in the level of acceptance of the panelists in sensory evaluation.
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Gezginc, Y; Topcal, F; Comertpay, S; Akyol, I
2015-03-01
The present study was conducted to evaluate the lactic acid- and acetaldehyde-producing abilities of lactic acid bacterial species isolated from traditionally manufactured Turkish yogurts using HPLC. The lactic acid bacterial species purified from the yogurts were the 2 most widely used species in industrial yogurt production: Streptococcus thermophilus and Lactobacillus bulgaricus. These bacteria have the ability to ferment hexose sugars homofermentatively to generate lactic acid and some carbonyl compounds, such as acetaldehyde through pyruvate metabolism. The levels of the compounds produced during fermentation influence the texture and the flavor of the yogurt and are themselves influenced by the chemical composition of the milk, processing conditions, and the metabolic activity of the starter culture. In the study, morphological, biochemical, and molecular characteristics were employed to identify the bacteria obtained from homemade yogurts produced in different regions of Turkey. A collection of 91 Strep. thermophilus and 35 L. bulgaricus strains were investigated for their lactic acid- and acetaldehyde-formation capabilities in various media such as cow milk, LM17 agar, and aerobic-anaerobic SM17 agar or de Man, Rogosa, and Sharpe agar. The amounts of the metabolites generated by each strain in all conditions were quantified by HPLC. The levels were found to vary depending on the species, the strain, and the growth conditions used. Whereas lactic acid production ranged between 0 and 77.9 mg/kg for Strep. thermophilus strains, it ranged from 0 to 103.5 mg/kg for L. bulgaricus. Correspondingly, the ability to generate acetaldehyde ranged from 0 to 105.9 mg/kg in Strep. thermophilus and from 0 to 126.9 mg/kg in L. bulgaricus. Our study constitutes the first attempt to determine characteristics of the wild strains isolated from traditional Turkish yogurts, and the approach presented here, which reveals the differences in metabolite production abilities of the wild lactic acid bacteria strains, holds the potential for the selection of the most desirable strains to be used as starters in commercial yogurt manufacture in the future. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
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Production of high molecular weight polylactic acid
Bonsignore, P.V.
1995-11-28
A degradable high molecular weight poly(lactic acid) is described. The poly(lactic acid) has a terminal end group of one of carboxyl or hydroxyl groups with low molecular weight poly(lactic acid) units coupled with linking agents of di-isocyanates, bis-epoxides, bis-oxazolines and bis-ortho esters. The resulting high molecular weight poly(lactic acid) can be used for applications taking advantage of the improved physical properties.
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Gomółka-Pawlicka, M; Uradziński, J
2003-01-01
The present study was aimed at determining the influence of 15 strains of lactic acid bacteria on the growth of 8 Yersinia enterocolitica strains in model set-ups, and in meat and ageing fermented sausages. The investigations were performed within the framework of three alternate stages which differed in respect to the products studied, the number of Lactobacillus sp. strains and, partly, methodological approach. The ratio between lactic acid bacteria and Yersinia enterocolitica strains studied was, depending on the variant of experiment, 1:1, 1:2 and 2:1, respectively. The study also considered water activity (aw) and pH of the products investigated. The results suggest that all the lactic acid bacteria strains used within the framework of the model set-ups had antagonistic effect on all the Salmonella sp. strains. However, this ability was not observed with respect to of tested lactic acid bacteria strains in meat and fermented sausage. This ability was possessed by one of the strains investigated--Lactobacillus helveticus T 78. The temperature and time of the incubation of sausages, but not aw and pH, were found to have a distinct influence on the antagonistic interaction between the bacteria tested.
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Bouteille, R; Gaudet, M; Lecanu, B; This, H
2013-04-01
When fermenting milk, lactic bacteria convert part of α- and β-lactoses into d- and l- lactic acids, causing a pH decrease responsible for casein coagulation. Lactic acid monitoring during fermentation is essential for the control of dairy gel textural and organoleptic properties, and is a way to evaluate strain efficiency. Currently, titrations are used to follow the quantity of acids formed during jellification of milk but they are not specific to lactic acid. An analytical method without the use of any reagent was investigated to quantify lactic acid during milk fermentation: in situ quantitative proton nuclear magnetic resonance spectroscopy. Two methods using in situ quantitative proton nuclear magnetic resonance spectroscopy were compared: (1) d- and l-lactic acids content determination, using the resonance of their methyl protons, showing an increase from 2.06 ± 0.02 to 8.16 ± 0.74 g/L during 240 min of fermentation; and (2) the determination of the α- and β-lactoses content, decreasing from 42.68 ± 0.02 to 30.76 ± 1.75 g/L for the same fermentation duration. The ratio between the molar concentrations of produced lactic acids and consumed lactoses enabled cross-validation, as the value (2.02 ± 0.18) is consistent with lactic acid bacteria metabolism. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
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Aspmo, Stein Ivar; Horn, Svein Jarle; Eijsink, Vincent G H
2005-07-01
Hydrolysates of cod viscera were tested as an alternative to commonly used complex nitrogen sources (peptones and/or extracts) for the type strains of the lactic acid bacteria Lactococcus lactis, Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus casei, Lactobacillus sakei and Pediococcus pentosaceus. Comparative studies with MRS-like media containing different nitrogen sources showed that all the fish hydrolysates performed equally well or better than commercial extracts/peptones for all selected lactic acid bacteria.
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Code of Federal Regulations, 2014 CFR
2014-07-01
...) Solvent Kaolinite-type clay Solid diluent, carrier Lactic acid Solvent Lactic acid, 2-ethylhexyl ester (CAS Reg. No. 6283-86-9) Solvent Lactic acid, 2-ethylhexyl ester, (2S)- (CAS Reg. No. 186817-80-1) Solvent Lactic acid, n-propyl ester, (S); (CAS Reg. No. 53651-69-7) Solvent Lauryl alcohol Surfactant...
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Monascus ruber as cell factory for lactic acid production at low pH.
Weusthuis, Ruud A; Mars, Astrid E; Springer, Jan; Wolbert, Emil Jh; van der Wal, Hetty; de Vrije, Truus G; Levisson, Mark; Leprince, Audrey; Houweling-Tan, G Bwee; Pha Moers, Antoine; Hendriks, Sjon Na; Mendes, Odette; Griekspoor, Yvonne; Werten, Marc Wt; Schaap, Peter J; van der Oost, John; Eggink, Gerrit
2017-07-01
A Monascus ruber strain was isolated that was able to grow on mineral medium at high sugar concentrations and 175g/l lactic acid at pH 2.8. Its genome and transcriptomes were sequenced and annotated. Genes encoding lactate dehydrogenase (LDH) were introduced to accomplish lactic acid production and two genes encoding pyruvate decarboxylase (PDC) were knocked out to subdue ethanol formation. The strain preferred lactic acid to glucose as carbon source, which hampered glucose consumption and therefore also lactic acid production. Lactic acid consumption was stopped by knocking out 4 cytochrome-dependent LDH (CLDH) genes, and evolutionary engineering was used to increase the glucose consumption rate. Application of this strain in a fed-batch fermentation resulted in a maximum lactic acid titer of 190g/l at pH 3.8 and 129g/l at pH 2.8, respectively 1.7 and 2.2 times higher than reported in literature before. Yield and productivity were on par with the best strains described in literature for lactic acid production at low pH. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.
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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.
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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
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Haag, Nicola Leonard; Nägele, Hans-Joachim; Fritz, Thomas; Oechsner, Hans
2015-02-01
A green biorefinery enables the material and energetic use of biomass via lactic acid and methane production. Different ensiling techniques were applied to maize and amaranth with the aim to increase the amount of lactic acid in the silage. In addition the methane formation potential of the ensiled samples and the remaining solid residues after separating the organic juice were assessed. Treating maize with homofermentative lactic acid bacteria in combination with carbonated lime increased the amount of lactic acid about 91.9%. For amaranth no additional lactic acid production was obtained by treating the raw material. Specific methane yields for the solid residues of amaranth were significantly lower in comparison to the corresponding silages. The most promising treatment resulted in a production of 127.9±4.1 g kg(-1) DM lactic acid and a specific methane yield for the solid residue of 349.5±6.6 lN kg(-1) ODM. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Long, M; Feng, W J; Li, P; Zhang, Y; He, R X; Yu, L H; He, J B; Jing, W Y; Li, Y M; Wang, Z; Liu, G W
2014-02-01
The aim of this study was to examine the effects of the acid-tolerant engineered bacterial strain Megasphaera elsdenii H6F32 (M. elsdenii H6F32) on ruminal pH and the lactic acid concentrations in simulated rumen acidosis conditions in vitro. A mixed culture of ruminal bacteria, buffer, and primarily degradable substrates was inoculated with equal numbers of M. elsdenii H6 or M. elsdenii H6F32. The pH and lactic acid concentrations in the mixed culture were determined at 0, 2, 4, 6, 8, 10, 12, 14, 16, and 18 h of incubation. Acid-tolerant M. elsdenii H6F32 reduced the accumulation of lactic acid and increased the pH value. These results indicate that acid-tolerant M. elsdenii H6F32 could be a potential candidate for preventing rumen acidosis. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Daoud, Walid A; Ngan, Mandy; Cheuk, Kevin
2010-02-01
In this study, nanocapsules of poly(L-lactic acid) (PLLA) containing lavender oil were synthesized by solvent evaporation emulsion. Poly(L-lactic acid) is a biodegradable aliphatic polyester derived from lactic acid formed by bacterial fermentation of glucose-rich substances. Lavender oil is a plant extract that finds uses in phytotherapy. It is reputed as anti-septic, anti-depressant and sleep promoter. Encapsulation is a technique used to encase tiny oil droplets with a thin and permeable coating that allows for a controlled release of the volatile oil. The size and morphology of the nanocapsules were characterized by scanning electron microscope. The particle size and distribution were measured by photon correlation spectroscopy. The time-controlled release of the lavender oil was studied and the use of the lavender capsules in the remedy of sleep disorder was investigated.
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Nsogning, Sorelle Dongmo; Fischer, Susann; Becker, Thomas
2018-08-01
Understanding lactic acid bacteria (LAB) fermentation behavior in malt wort is a milestone towards flavor improvement of lactic acid fermented malt beverages. Therefore, this study aims to outline deficiencies that may exist in malt wort fermentation. First, based on six LAB strains, cell viability and vitality were evaluated. Second, sugars, organic acids, amino acids, pH value and buffering capacity (BC) were monitored. Finally, the implication of key amino acids, fructose and wort BC on LAB growth was determined. Short growth phase coupled with prompt cell death and a decrease in metabolic activity was observed. Low wort BC caused rapid pH drop with lactic acid accumulation, which conversely increased the BC leading to less pH change at late-stage fermentation. Lactic acid content (≤3.9 g/L) was higher than the reported inhibitory concentration (1.8 g/L). Furthermore, sugars were still available but fructose and key amino acids lysine, arginine and glutamic acid were considerably exhausted (≤98%). Wort supplementations improved cell growth and viability leading to conclude that key amino acid depletion coupled with low BC limits LAB growth in malt wort. Then, a further increase in organic acid reduces LAB viability. This knowledge opens doors for LAB fermentation process optimization in malt wort. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Verstraelen, Hans; Vervaet, Chris; Remon, Jean-Paul
2016-01-01
Bacterial vaginosis is a prevalent state of dysbiosis of the vaginal microbiota with wide-ranging impact on human reproductive health. Based on recent insights in community ecology of the vaginal microbiome, we hypothesize that sustained vaginal DL-lactic acid enrichment will enhance the recruitment of lactobacilli, while counteracting bacterial vaginosis-associated bacteria. We therefore aimed to develop an intravaginal device that would be easy to insert and remove, while providing sustained DL-lactic acid release into the vaginal lumen. The final prototype selected is a vaginal ring matrix system consisting of a mixture of ethylene vinyl acetate and methacrylic acid-methyl methacrylate copolymer loaded with 150 mg DL-lactic acid with an L/D-lactic acid ratio of 1:1. Preclinical safety assessment was performed by use of the Slug Mucosal Irritation test, a non-vertebrate assay to evaluate vaginal mucosal irritation, which revealed no irritation. Clinical safety was evaluated in a phase I trial with six healthy nulliparous premenopausal volunteering women, with the investigational drug left in place for 7 days. Colposcopic monitoring according to the WHO/CONRAD guidelines for the evaluation of vaginal products, revealed no visible cervicovaginal mucosal changes. No adverse events related to the investigational product occurred. Total release from the intravaginal ring over 7 days was estimated through high performance liquid chromatography at 37.1 (standard deviation 0.9) mg DL-lactic acid. Semisolid lactic acid formulations have been studied to a limited extent in the past and typically consist of a large volume of excipients and very high doses of lactic acid, which is of major concern to mucosal safety. We have documented the feasability of enriching the vaginal environment with pure DL-lactic acid with a prototype intravaginal ring. Though the efficacy of this platform remains to be established possibly requiring further development, this approach may offer a novel avenue to modulate and protect the vaginal microbiota. Trial Registration U.S. National Institutes of Health ClinicalTrials.gov NCT02314429 PMID:27093291
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de Barros, Jefferson C.; da Conceição, Maria Lúcia; Neto, Nelson Justino Gomes; da Costa, Ana Caroliny Vieira; de Souza, Evandro Leite
2012-01-01
This study assessed the occurrence of an enhancing inhibitory effect of the combined application of Origanum vulgare L. essential oil and lactic acid against Staphylococcus aureus by the determination of Fractional Inhibitory Concentration (FIC) index and cell viability in meat broth and meat model. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the oil was 0.6 and 1.25 µL.mL-1, respectively. Lactic acid showed MIC and MBC of 2.5 and 5µL.mL-1, respectively. FIC indices of the combined application of the oil and lactic acid were 0.5 showing a synergic interaction. The essential oil and lactic acid showed similar (p>0.05) anti-S. aureus effect in meat broth over 96 h of exposure. Treatment with essential oil or lactic acid presented a smaller anti-staphylococcal effect in meat in comparison to meat broth. No significant difference (p>0.05) was found for the microbial counts in meat treated with each antimicrobial alone or in mixture. These results could arise as an interesting approach for the improvement of food preservation using more natural procedures, considering the current demand of consumer and sensory quality of foods. PMID:24031936
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Okano, Kenji; Zhang, Qiao; Yoshida, Shogo; Tanaka, Tsutomu; Ogino, Chiaki; Fukuda, Hideki; Kondo, Akihiko
2010-01-01
In order to achieve direct fermentation of an optically pure D: -lactic acid from cellulosic materials, an endoglucanase from a Clostridium thermocellum (CelA)-secreting plasmid was introduced into an L: -lactate dehydrogenase gene (ldhL1)-deficient Lactobacillus plantarum (ldhL1) bacterial strain. CelA expression and its degradation of beta-glucan was confirmed by western blot analysis and enzyme assay, respectively. Although the CelA-secreting ldhL1 assimilated cellooligosaccharides up to cellohexaose (although not cellotetraose), the main end product was acetic acid, not lactic acid, due to the conversion of lactic acid to acetic acid. Cultivation under anaerobic conditions partially suppressed this conversion resulting in the production of 1.27 g/l of D: -lactic acid with a high optical purity of 99.5% from a medium containing 2 g/l of cellohexaose. Subsequently, D: -lactic acid fermentation from barley beta-glucan was carried out with the addition of Aspergillus aculeatus beta-glucosidase produced by recombinant Aspergillus oryzae and 1.47 g/l of D: -lactic was produced with a high optical purity of 99.7%. This is the first report of direct lactic acid fermentation from beta-glucan and a cellooligosaccharide that is a more highly polymerized sugar than cellotriose.
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Michelz Beitel, Susan; Fontes Coelho, Luciana; Sass, Daiane Cristina; Contiero, Jonas
2017-01-01
The interest in the production of lactic acid has increased due to its wide range of applications. In the present study, the variables that affect fermentative D(-) lactic acid production were investigated: neutralizing agents, pH, temperature, inoculum percentage, agitation, and concentration of the medium components. An experimental design was applied to determine the optimal concentrations of the medium components and fermentation was studied using different feeding strategies. High production (122.41 g/L) and productivity (3.65 g/L·h) were efficiently achieved by Sporolactobacillus nakayamae in 54 h using a multipulse fed-batch technique with an initial medium containing 35 g/L of yeast extract (byproduct of alcohol production), 60 g/L of crystallized sugar, and 7.5 mL/L of salts. The fermentation process was conducted at 35°C and pH 6.0 controlled by NaOH with a 20% volume of inoculum and agitation at 125 rpm. The production of a high optically pure concentration of D(-) lactic acid combined with an environmentally friendly NaOH-based process demonstrates that S. nakayamae is a promising strain for D(-) lactic acid production.
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Yamada, Ryosuke; Wakita, Kazuki; Mitsui, Ryosuke; Ogino, Hiroyasu
2017-09-01
Utilization of renewable feedstocks for the production of bio-based chemicals such as d-lactic acid by engineering metabolic pathways in the yeast Saccharomyces cerevisiae has recently become an attractive option. In this study, to realize efficient d-lactic acid production by S. cerevisiae, the expression of 12 glycolysis-related genes and the Leuconostoc mesenteroides d-LDH gene was optimized using a previously developed global metabolic engineering strategy, and repeated batch fermentation was carried out using the resultant strain YPH499/dPdA3-34/DLDH/1-18. Stable d-lactic acid production through 10 repeated batch fermentations was achieved using YPH499/dPdA3-34/DLDH/1-18. The average d-lactic acid production, productivity, and yield with 10 repeated batch fermentations were 60.3 g/L, 2.80 g/L/h, and 0.646, respectively. The present study is the first report of the application of a global metabolic engineering strategy for bio-based chemical production, and it shows the potential for efficient production of such chemicals by global metabolic engineering of the yeast S. cerevisiae. Biotechnol. Bioeng. 2017;114: 2075-2084. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
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Shojaeimehr, Tahereh; Rahimpour, Farshad; Schwarze, Michael; Repke, Jens-Uwe; Godini, Hamid Reza; Wozny, Günter
2018-04-15
The present study evaluates the capability of ion exclusion chromatography (IEC) of short chain aliphatic carboxylic acids using a cation exchange column (8% sulfonated cross-linked styrene-divinylbenzene copolymer) in different experimental conditions. Since one of the prerequisites to the development of an efficient carboxylic acid separation process is to obtain the optimum operational conditions, response surface methodology (RSM) was used to develop an approach to evaluate carboxylic acids separation process in IEC columns. The effect of the operating conditions such as column temperature, sulfuric acid concentration as the mobile phase, and the flow rate was studied using Central Composite Face (CCF) design. The optimum operating conditions for the separate injection of lactic acid and acetic acid is temperature of 75 °C, sulfuric acid concentration of 0.003 N for both acids and flow rate of 0.916 (0.886) mL/min for acetic acid (lactic acid). Likewise, the optimum conditions for the simultaneous injection of acetic and lactic acid mixture are the column temperature of 68 °C, sulfuric acid concentration of 0.0003 N, and flow rate of 0.777 mL/min. In the next step, the adsorption equilibria of acetic acid and lactic acid on the stationary phase were investigated through a series of Frontal Analysis (FA), Frontal Analysis by Characteristic Points (FACP), and using Langmuir isotherm model. The results showed an excellent agreement between the model and experimental data. Finally, the results of thermodynamic studies proved that the IEC process for separation of acetic and lactic acid is a spontaneous, feasible, exothermic, and random process with a physical adsorption mechanism. The results of the current paper can be a valuable information in the stages of designing IEC columns for separation of aliphatic carboxylic acids. Copyright © 2018 Elsevier B.V. All rights reserved.
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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.
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Escudero, M E; Velázquez, L; Favier, G; de Guzmán, A M
2003-06-01
This study assessed the effectiveness of 200 and 500 ppm of chlorine and organic acids (0.5% lactic acid and 0.5% citric acid) in wash solutions, and UV radiation for reducing Escherichia coli O157:H7 and Yersinia enterocolitica on apples contaminated by two different methods. Residual levels of these pathogens after different treatments were compared. On dip inoculated apples, Y. enterocolitica reductions of 2.66 and 2.77 logs were obtained with 200 and 500 ppm chlorine combined with 0.5% lactic acid, respectively. The E. coli O157:H7 population decreased 3.35 log with 0.5% lactic acid wash solution, and 2.72 and 2.62 logs after 500 ppm chlorine and 500 ppm chlorine plus 0.5% lactic acid treatments, respectively. Similar reductions were obtained with UV radiation. On spot inoculated apples, significant (p < 0.05) decreases of 4.67 and 4.58 logs were observed in E. coli O157:H7 and Y. enterocolitica levels, respectively, after 500 ppm chlorine plus 0.5% lactic acid treatment as compared with the control. In sectioned apples, microorganisms infiltrated in inner core region and pulp were not significantly (p < 0.05) affected by disinfection treatments. No pathogens were detected in the natural microflora on apples. Reductions such as those obtained with 500 ppm chlorine plus 0.5% lactic acid solution were very proximal to the 5-log score required by FDA for apple disinfection.
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Effects of selected lactic acid bacteria on the characteristics of amaranth sourdough.
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.
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Increased plasma d-lactic acid associated with impaired memory in rats.
Hanstock, T L; Mallet, P E; Clayton, E H
2010-12-02
d-Lactic acidosis is associated with memory impairment in humans. Recent research indicates that d-lactic acid may inhibit the supply of energy from astrocytes to neurons involved with memory formation. However, little is known about the effects of increased hind-gut fermentation due to changes in diet on circulating lactic acid concentrations and memory. Thirty-six male Wistar rats were fed three dietary treatments: a commercial rat and mouse chow, a soluble carbohydrate based diet or a fermentable carbohydrate based diet. The parameters estimating memory were examined by employing the object recognition test. Physical parameters of fermentation including hind-gut and plasma lactic acid concentrations were examined after sacrifice, either 3 or 21h after feeding. Increased fermentation in the hind-gut of rats, indicated by lower caecum pH, was associated with increased plasma l-lactic acid (r=-0.41, p=0.020) and d-lactic acid (r=-0.33, p=0.087). Memory, being able to discriminate between a familiar and a novel object during the object recognition test, was reduced with increasing plasma d-lactic acid (r=-0.51, p=0.021). Memory impairment was associated with alterations in plasma d-lactic acid following the fermentation of carbohydrate in the hind-gut. Further work is still required to determine whether these effects are mediated centrally or via direct connections through the enteric nervous system. Copyright © 2010 Elsevier Inc. All rights reserved.
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Henry, H; Marmy Conus, N; Steenhout, P; Béguin, A; Boulat, O
2012-04-01
D-lactic acid in urine originates mainly from bacterial production in the intestinal tract. Increased D-lactate excretion as observed in patients affected by short bowel syndrome or necrotizing enterocolitis reflects D-lactic overproduction. Therefore, there is a need for a reliable and sensitive method able to detect D-lactic acid even at subclinical elevation levels. A new and highly sensitive method for the simultaneous determination of L- and D-lactic acid by a two-step procedure has been developed. This method is based on the concentration of lactic acid enantiomers from urine by supported liquid extraction followed by high-performance liquid chromatography-tandem mass spectrometry. The separation was achieved by the use of an Astec Chirobiotic™ R chiral column under isocratic conditions. The calibration curves were linear over the ranges of 2-400 and 0.5-100 µmol/L respectively for L- and D-lactic acid. The limit of detection of D-lactic acid was 0.125 µmol/L and its limit of quantification was 0.5 µmol/L. The overall accuracy and precision were well within 10% of the nominal values. The developed method is suitable for production of reference values in children and could be applied for accurate routine analysis. Copyright © 2011 John Wiley & Sons, Ltd.
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Development of a new lactic acid bacterial inoculant for fresh rice straw silage.
Kim, Jong Geun; Ham, Jun Sang; Li, Yu Wei; Park, Hyung Soo; Huh, Chul-Sung; Park, Byung-Chul
2017-07-01
Effects of newly isolated Lactobacillus plantarum on the fermentation and chemical composition of fresh rice straw silage was evaluated in this study. Lactic acid bacteria (LAB) from good crop silage were screened by growing them in MRS broth and a minimal medium with low carbohydrate content. Selected LAB (LAB 1821) were Gram-positive, rods, catalase negative, and were identified to be Lactobacillus plantarum based on their biochemical characteristics and a 16S rRNA analysis. Fresh rice straw was ensiled with two isolated LAB (1821 and 1841), two commercial inoculants (HM/F and P1132) and no additive as a control. After 2 months of storage at ambient temperature, rice straw silages treated with additives were well-preserved, the pH values and butyric and acetic acid contents were lower, and the lactic acid content and lactic/acetic acid ratio were higher than those in the control (p<0.05). Acidity (pH) was lowest, and lactic acid highest, in 1821-treated silage (p<0.05). The NH 3 -N content decreased significantly in inoculant-treated silage (p<0.05) and the NH 3 -N content in 1821-treated silage was lowest among the treatments. The dry matter (DM) content of the control silage was lower than that of fresh rice straw (p<0.05), while that of the 1841- and p1174-inoculant-treated silages was significantly higher than that of HM/F-treated silage. Microbial additives did not have any significant (p>0.05) effect on acid detergent fiber or neutral detergent fiber contents. Crude protein (CP) content and in vitro DM digestibility (IVDMD) increased after inoculation of LAB 1821 (p<0.05). LAB 1821 increased the CP, IVDMD, lactic acid content and ratio of lactic acid to acetic acid in rice straw silage and decreased the pH, acetic acid, NH 3 -N, and butyric acid contents. Therefore, adding LAB 1821 improved the fermentation quality and feed value of rice straw silage.
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Antifungal activity of Leuconostoc citreum and Weissella confusa in rice cakes.
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.
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[Lactic acid inhibits the formation of semen-derived amyloid fibrils].
Li, Jin-Qing; Song, Ya-Li; Xun, Tian-Rong; Tan, Sui-Yi; Liu, Shu-Wen
2017-07-20
To investigate the inhibitory effect of lactic acid on semen-derived amyloid (SEVI) fibril formation. PAP248-286 (2 mg/mL) was incubated with 4.0, 2.0, 1.0, 0.5, 0.25, and 0.125 mg/mL of lactic acid. After incubation for different times, aliquots were drawn from each sample for Thioflavin T (ThT) and Congo red staining to monitor semen-derived amyloid fibril formation. The β sheet structure formation of PAP248-286 was measured by circular dichroism spectrum, and the morphology of amyloid fibrils incubated with or without lactic acid was observed with transmission electron microscopy (TEM). The enhancing effect of amyloid fibril incubated with lactic acid at different time points was determined using virus infection assay. PAP248-286 (2 mg/mL) was incubated with dilutions of vaginal secretion from healthy women, and amyloid fibril formation was detected with ThT and Congo red staining. Lactic acid inhibited SEVI fibril formation in a dose-dependent manner in vitro. Lactic acid at 0.5 mg/mL completely inhibited 2 mg/mL SEVI fibril formation within 48 h. After incubation for 48 h, lactic acid at 1 mg/mL inhibited the formation of β-sheet structure of SEVI (2 mg/mL) and completely inhibited 2 mg/mL PAP248-286 aggregation as observed with TEM. In the presence of lactic acid, PAP248-286 lost the ability to enhance virus infection. Vaginal secretion inhibited SEVI fibril formation in a dose-dependent manner, and virtually no SEVI fibril occurred after incubation of 2 mg/mL PAP248-286 with 67% vaginal secretion. Lactic acid inhibits SEVI fibril formation in vitro.
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Betaine and Beet Molasses Enhance L-Lactic Acid Production by Bacillus coagulans
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
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Betaine and beet molasses enhance L-lactic acid production by Bacillus coagulans.
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.
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Tashiro, Yukihiro; Kaneko, Wataru; Sun, Yanqi; Shibata, Keisuke; Inokuma, Kentaro; Zendo, Takeshi; Sonomoto, Kenji
2011-03-01
We isolated and characterized a D-lactic acid-producing lactic acid bacterium (D-LAB), identified as Lactobacillus delbrueckii subsp. lactis QU 41. When compared to Lactobacillus coryniformis subsp. torquens JCM 1166 (T) and L. delbrueckii subsp. lactis JCM 1248 (T), which are also known as D-LAB, the QU 41 strain exhibited a high thermotolerance and produced D-lactic acid at temperatures of 50 °C and higher. In order to optimize the culture conditions of the QU 41 strain, we examined the effects of pH control, temperature, neutralizing reagent, and initial glucose concentration on D-lactic acid production in batch cultures. It was found that the optimal production of 20.1 g/l D-lactic acid was acquired with high optical purity (>99.9% of D-lactic acid) in a pH 6.0-controlled batch culture, by adding ammonium hydroxide as a neutralizing reagent, at 43 °C in MRS medium containing 20 g/l glucose. As a result of product inhibition and low cell density, continuous cultures were investigated using a microfiltration membrane module to recycle flow-through cells in order to improve D-lactic acid productivity. At a dilution rate of 0.87 h(-1), the high cell density continuous culture exhibited the highest D-lactic acid productivity of 18.0 g/l/h with a high yield (ca. 1.0 g/g consumed glucose) and a low residual glucose (<0.1 g/l) in comparison with systems published to date.
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Alahakoon, Amali U.; Jayasena, Dinesh D.; Jung, Samooel; Kim, Sun Hyo
2014-01-01
Chicken breast meat was injected with calcium chloride alone and in combination with lactic acid (0.01% and 0.002%, respectively). The inhibitory effects of the treatments on microbial growth were determined in the injected chicken breast meat stored at 4°C under aerobic packaging condition for 0, 3, and 7 d. Calcium chloride combined with 0.002% and 0.01% lactic acid reduced microbial counts by 0.14 and 1.08 Log CFU/g, respectively, however, calcium chloride alone was unable to inhibit microbial growth. Calcium chloride combined with 0.01% lactic acid was the most effective antimicrobial treatment and resulted in the highest initial redness value. Calcium chloride alone and combined with lactic acid suppressed changes in pH and the Hunter color values during storage. However, injection of calcium chloride and lactic acid had adverse effects on lipid oxidation and sensory characteristics. The higher TBARS values were observed in samples treated with calcium chloride and lactic acid when compared to control over the storage period. Addition of calcium chloride and lactic acid resulted in lower sensory scores for parameters tested, except odor and color, compared to control samples. Therefore, the formulation should be improved in order to overcome such defects prior to industrial application. PMID:26760942
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Estimation of lactic acid bacterial cell number by DNA quantification.
Ishii, Masaki; Matsumoto, Yasuhiko; Sekimizu, Kazuhisa
2018-01-01
Lactic acid bacteria are provided by fermented foods, beverages, medicines, and supplements. Because the beneficial effects of medicines and supplements containing functional lactic acid bacteria are related to the bacterial cell number, it is important to establish a simple method for estimating the total number of lactic acid bacterial cells in the products for quality control. Almost all of the lactic acid bacteria in the products are dead, however, making it difficult to estimate the total number of lactic acid bacterial cells in the products using a standard colony-counting method. Here we estimated the total lactic acid bacterial cell number in samples containing dead bacteria by quantifying the DNA. The number of viable Enterococcus faecalis 0831-07 cells decreased to less than 1 × 10 -8 by 15 min of heat treatment at 80°C. The amount of extracted DNA from heat-treated cells was 78% that of non-heated cells. The number of viable Lactobacillus paraplantarum 11-1 cells decreased to 1 × 10 -4 after 4 days culture. The amount of extracted DNA of the long-cultured cells, however, was maintained at 97%. These results suggest that cell number of lactic acid bacteria killed by heat-treatment or long-term culture can be estimated by DNA quantification.
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USDA-ARS?s Scientific Manuscript database
A study was conducted to examine the ability of Campylobacter spp. to grow aerobically in media supplemented with selected organic acids. Basal broth media composed of tryptose, yeast extract, and a mineral-vitamin solution was supplemented with a-ketoglutaric, lactic, and/or fumaric acids. The fina...
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USDA-ARS?s Scientific Manuscript database
Fibers of poly(lactic acid) (PLA) blended with p-toluenesulfonic acid-doped polyaniline, PAni.TSA, were obtained by lectrospinning, following a factorial design which was used mainly to study the effect of four process parameters (PLA solution concentration, PAni solution concentration, applied volt...
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Short communication: Conversion of lactose and whey into lactic acid by engineered yeast.
Turner, Timothy L; Kim, Eunbee; Hwang, ChangHoon; Zhang, Guo-Chang; Liu, Jing-Jing; Jin, Yong-Su
2017-01-01
Lactose is often considered an unwanted and wasted byproduct, particularly lactose trapped in acid whey from yogurt production. But using specialized microbial fermentation, the surplus wasted acid whey could be converted into value-added chemicals. The baker's yeast Saccharomyces cerevisiae, which is commonly used for industrial fermentation, cannot natively ferment lactose. The present study describes how an engineered S. cerevisiae yeast was constructed to produce lactic acid from purified lactose, whey, or dairy milk. Lactic acid is an excellent proof-of-concept chemical to produce from lactose, because lactic acid has many food, pharmaceutical, and industrial uses, and over 250,000 t are produced for industrial use annually. To ferment the milk sugar lactose, a cellodextrin transporter (CDT-1, which also transports lactose) and a β-glucosidase (GH1-1, which also acts as a β-galactosidase) from Neurospora crassa were expressed in a S. cerevisiae strain. A heterologous lactate dehydrogenase (encoded by ldhA) from the fungus Rhizopus oryzae was integrated into the CDT-1/GH1-1-expressing strain of S. cerevisiae. As a result, the engineered strain was able to produce lactic acid from purified lactose, whey, and store-bought milk. A lactic acid yield of 0.358g/g of lactose was achieved from whey fermentation, providing an initial proof of concept for the production of value-added chemicals from excess industrial whey using engineered yeast. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
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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.
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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.
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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
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Highly efficient production of L-lactic acid from xylose by newly isolated Bacillus coagulans C106.
Ye, Lidan; Zhou, Xingding; Hudari, Mohammad Sufian Bin; Li, Zhi; Wu, Jin Chuan
2013-03-01
Cost-effective production of optically pure lactic acid from lignocellulose sugars is commercially attractive but challenging. Bacillus coagulans C106 was isolated from environment and used to produce l-lactic acid from xylose at 50°C and pH 6.0 in mineral salts medium containing 1-2% (w/v) of yeast extract without sterilizing the medium before fermentation. In batch fermentation with 85g/L of xylose, lactic acid titer and productivity reached 83.6g/L and 7.5g/Lh, respectively. When fed-batch (120+80+60g/L) fermentation was applied, they reached 215.7g/L and 4.0g/Lh, respectively. In both cases, the lactic acid yield and optical purity reached 95% and 99.6%, respectively. The lactic acid titer and productivity on xylose are the highest among those ever reported. Ca(OH)2 was found to be a better neutralizing agent than NaOH in terms of its giving higher lactic acid titer (1.2-fold) and productivity (1.8-fold) under the same conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Membrane-mediated extractive fermentation for lactic acid production from cellulosic biomass.
Chen, R; Lee, Y Y
1997-01-01
Lactic acid production from cellulosic biomass by cellulase and Lactobacillus delbrueckii was studied in a fermenter-extractor employing a microporous hollow fiber membrane (MHF). This bioreactor system was operated under a fed-batch mode with continuous removal of lactic acid by anin situ extraction. A tertiary amine (Alamine 336) was used as an extractant for lactic acid. The extraction capacity of Alamine 336 is greatly enhanced by addition of alcohol. Long-chain alcohols serve well for this purpose since they are less toxic to micro-organism. Addition of kerosene, a diluent, was necessary to reduce the solvent viscosity. A solvent mixture of 20% Alamine 336, 40% oleyl alcohol, and 40% kerosene was found to be most effective in the extraction of lactic acid. Progressive change of pH from an initial value of 5.0 down to 4.3 has significantly improved the overall performance of the simultaneous saccharification and extractive fermentation over that of constant pH operation. The change of pH was applied to promote cell growth in the early phase, and extraction in the latter phase.
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Djukić-Vuković, Aleksandra P; Mojović, Ljiljana V; Vukašinović-Sekulić, Maja S; Rakin, Marica B; Nikolić, Svetlana B; Pejin, Jelena D; Bulatović, Maja L
2012-09-15
Expansion of lactic acid applications, predominantly for the preparation of biodegradable polymers increased the research interest for new, economically favourable production processes. Liquid stillage from bioethanol production can be an inexpensive, valuable source of nutrients for growth of lactic acid bacteria. Utilisation of residual biomass with spent fermentation media as a functional animal feed can greatly influence the process value and its ecological aspect. In this paper, the kinetics of lactic acid and biomass production on liquid stillage by Lactobacillus rhamnosus ATCC 7469 was studied. In addition, the impact of temperature, inoculum concentration, shaking and pH control by addition of CaCO(3) was evaluated. Maximal lactic acid yield of 73.4%, as well as high biomass production (3×10(8) CFU ml(-1)) were achieved under selected conditions (41°C, 5% (v/v) of inoculum, 1% (w/v) of CaCO(3), initial pH of 6.5 and shaking rate of 90 rpm). These results were achieved without supplementation of the stillage with nitrogen or mineral sources. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Findrik, Zvjezdana; Németh, Gergely; Gubicza, László; Bélafi-Bakó, Katalin; Vasić-Rački, Durđa
2012-05-01
In this paper esterification of ethanol and lactic acid catalyzed by Candida antarctica B (Novozyme 435) in ionic liquid (Cyphos 104) was studied. The influence of different variables on lipase enantioselectivity and lactic acid conversion was investigated. The variables investigated were ionic liquid mass/lipase mass ratio, water content, alcohol excess and temperature. Using the Design Expert software 2(3) factorial experimental plan (two levels, three factors) was performed to ascertain the effect of selected variables and their interactions on the ethyl lactate enantiomeric excess and lactic acid conversion. The results of the experiments and statistical processing suggest that temperature and alcohol excess have the highest effect on the ethyl lactate enantiomeric excess, while temperature and water content have the highest influence on the lactic acid conversion. The statistical mathematical model developed on the basis of the experimental data showed that the highest enantiomeric excess achieved in the investigated variable range is 34.3%, and the highest conversion is 63.8% at the initial conditions of water content at 8%; 11-fold molar excess of alcohol and temperature at 30 °C.
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Lu, Zhengdong; Lu, Mingbo; He, Feng; Yu, Longjiang
2009-03-01
In order to reduce the raw material cost of d-lactic acid fermentation, the unpolished rice from aging paddy was used as major nutrient source in this study. The unpolished rice saccharificate, wheat bran powder and yeast extract were employed as carbon source, nitrogen source and growth factors, respectively. Response surface methodology (RSM) was applied to optimize the dosages of medium compositions. As a result, when the fermentation was carried out under the optimal conditions for wheat bran powder (29.10g/l) and yeast extract (2.50g/l), the d-lactic acid yield reached 731.50g/kg unpolished rice with a volumetric production rate of 1.50g/(lh). In comparison with fresh corn and polished rice, the d-lactic acid yield increased by 5.79% and 8.71%, and the raw material cost decreased by 65% and 52%, respectively, when the unpolished rice was used as a major nutrient source. These results might provide a reference for the industrial production of d-lactic acid.
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Leroy, Frédéric; De Vuyst, Luc
2003-01-01
The use of bacteriocin-producing lactic acid bacteria for improved food fermentation processes seems promising. However, lack of fundamental knowledge about the functionality of bacteriocin-producing strains under food fermentation conditions hampers their industrial use. Predictive microbiology or a mathematical estimation of microbial behavior in food ecosystems may help to overcome this problem. In this study, a combined model was developed that was able to estimate, from a given initial situation of temperature, pH, and nutrient availability, the growth and self-inhibition dynamics of a bacteriocin-producing Lactobacillus sakei CTC 494 culture in (modified) MRS broth. Moreover, the drop in pH induced by lactic acid production and the bacteriocin activity toward Listeria as an indicator organism were modeled. Self-inhibition was due to the depletion of nutrients as well as to the production of lactic acid. Lactic acid production resulted in a pH drop, an accumulation of toxic undissociated lactic acid molecules, and a shift in the dissociation degree of the growth-inhibiting buffer components. The model was validated experimentally. PMID:12571034
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Heme and menaquinone induced electron transport in lactic acid bacteria
Brooijmans, Rob; Smit, Bart; Santos, Filipe; van Riel, Jan; de Vos, Willem M; Hugenholtz, Jeroen
2009-01-01
Background For some lactic acid bacteria higher biomass production as a result of aerobic respiration has been reported upon supplementation with heme and menaquinone. In this report, we have studied a large number of species among lactic acid bacteria for the existence of this trait. Results Heme- (and menaquinone) stimulated aerobic growth was observed for several species and genera of lactic acid bacteria. These include Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacilllus brevis, Lactobacillus paralimentarius, Streptococcus entericus and Lactococcus garviae. The increased biomass production without further acidification, which are respiration associated traits, are suitable for high-throughput screening as demonstrated by the screening of 8000 Lactococcus lactis insertion mutants. Respiration-negative insertion-mutants were found with noxA, bd-type cytochrome and menaquinol biosynthesis gene-disruptions. Phenotypic screening and in silico genome analysis suggest that respiration can be considered characteristic for certain species. Conclusion We propose that the cyd-genes were present in the common ancestor of lactic acid bacteria, and that multiple gene-loss events best explains the observed distribution of these genes among the species. PMID:19480672
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Cheirsilp, Benjamas; Suksawang, Suwannee; Yeesang, Jarucha; Boonsawang, Piyarat
2018-01-01
Kefiran is a functional exopolysaccharide produced by Lactobacillus kefiranofaciens originated from kefir, traditional fermented milk in the Caucasian Mountains, Russia. Kefiran is attractive as thickeners, stabilizers, emulsifiers, gelling agents and also has antimicrobial and antitumor activity. However, the production costs of kefiran are still high mainly due to high cost of carbon and nitrogen sources. This study aimed to produce kefiran and its co-product, lactic acid, from low-cost industrial byproducts. Among the sources tested, whey lactose (at 2% sugar concentration) and spent yeast cells hydrolysate (at 6 g-nitrogen/L) gave the highest kefiran of 480 ± 21 mg/L along with lactic acid of 20.1 ± 0.2 g/L. The combination of these two sources and initial pH were optimized through Response Surface Methodology. With the optimized medium, L. kefiranofaciens produced more kefiran and lactic acid up to 635 ± 7 mg/L and 32.9 ± 0.7 g/L, respectively. When the pH was controlled to alleviate the inhibition from acidic pH, L. kefiranofaciens could consume all sugars and produced kefiran and lactic acid up to 1693 ± 29 mg/L and 87.49 ± 0.23 g/L, respectively. Moreover, the fed-batch fermentation with intermittent adding of whey lactose improved kefiran and lactic acid productions up to 2514 ± 93 mg/L and 135 ± 1.75 g/L, respectively. These results indicate the promising approach to economically produce kefiran and lactic acid from low-cost nutrient sources.
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Ho, Van Thi Thuy; Fleet, Graham H; Zhao, Jian
2018-08-20
Cocoa beans (Theobroma cacao L.) are the raw material for chocolate production. Fermentation of the bean pulp by microorganisms is essential for developing the precursors of chocolate flavour. Currently, the cocoa fermentation is still conducted by an uncontrolled traditional process via a consortium of indigenous species of yeasts, lactic acid bacteria and acetic acid bacteria. Although the essential contribution of yeasts to the production of good quality beans and, typical chocolate character is generally agreed, the roles of lactic acid bacteria and acetic acid bacteria are less certain. The objective of this study was to investigate the contribution of LAB and AAB in cocoa bean fermentation by conducting small scale laboratory fermentations under aseptic conditions, inoculated with different groups of microorganisms previously isolated from spontaneous cocoa fermentations. The inoculation protocols were: (1) four yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii, Kluyveromyces marxianus and Saccharomyces cerevisiae; (2) four yeasts plus the lactic acid bacteria Lactobacillus plantarum and Lactobacillus fermentum; (3) four yeasts plus the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateuri and (4) four yeasts plus two lactic acid bacteria and two acetic acid bacteria. Only the inoculated species were detected in the microbiota of their respective fermentations. Beans from the inoculated fermentations showed no significant differences in colour, shell weights and concentrations of residual sugars, alcohols and esters (p>0.05), but they were slightly different in contents of lactic acid and acetic acid (p<0.05). All beans were fully brown and free of mould. Residual sugar levels were less than 2.6 mg/g while the shell contents and ethanol were in the range of 11-13.4% and 4.8-7 mg/g, respectively. Beans fermented in the presence of LAB contained higher levels of lactic acid (0.6-1.2 mg/g) whereas higher concentrations of acetic acid (1.8-2.2 mg/g) were detected in beans inoculated with AAB. Triangle and hedonic sensory evaluations of chocolates prepared from beans taken from the three fermentations showed no significant differences (p > 0.05). It was concluded that the growth of lactic acid bacteria and acetic acid bacteria may not be essential for the fermentation of cocoa beans. Copyright © 2018 Elsevier B.V. All rights reserved.
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Lactose behaviour in the presence of lactic acid and calcium.
Wijayasinghe, Rangani; Vasiljevic, Todor; Chandrapala, Jayani
2016-08-01
Physical properties of lactose appeared influenced by presence of lactic acid in the system. Some other components such as Ca may further attenuate lactose behaviour and impact its phase transition. A model-based study was thus implemented with varying concentrations of Ca (0·12, 0·072 or 0·035% w/w) and lactic acid (0·05, 0·2, 0·4 or 1% w/w) in establishing the effects of these two main acid whey constituents on lactose phase behaviour. Concentrated solutions (50% w/w) containing lactose, lactic acid and Ca were analysed for thermal behaviour and structural changes by Differential Scanning Colorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR), respectively. Presence of 1% (w/w) lactic acid and 0·12% (w/w) Ca in lactose solution significantly increased the evaporation enthalpy of water, delayed and increased the energy required for lactose crystallisation as compared to pure lactose. FTIR analysis indicated a strong hydration layer surrounding lactose molecules, restricting water mobility and/or inducing structural changes of lactose, hindering its crystallisation. The formation of calcium lactate, which restricts the diffusion of lactose molecules, is also partly responsible. It appears that Ca removal from acid whey may be a necessary step in improving the processability of acid whey.
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Zhou, Xingding; Ye, Lidan; Wu, Jin Chuan
2013-05-01
A thermophilic Bacillus coagulans WCP10-4 with tolerance to high concentration of glucose was isolated from soil and used to produce optically pure L-lactic acid from glucose and starch. In batch fermentation at pH 6.0, 240 g/L of glucose was completely consumed giving 210 g/L of L-lactic acid with a yield of 95 % and a productivity of 3.5 g/L/h. In simultaneous saccharification and fermentation at 50 °C without sterilizing the medium, 200 g/L of corn starch was completely consumed producing 202.0 g/L of L-lactic acid. To the best of our knowledge, this strain shows the highest osmotic tolerance to glucose among the strains ever reported for lactic acid production. This is the first report of simultaneous saccharification and fermentation of starch for lactic acid production under a non-sterilized condition.
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Witkin, Steven S; Mendes-Soares, Helena; Linhares, Iara M; Jayaram, Aswathi; Ledger, William J; Forney, Larry J
2013-08-06
We evaluated levels of vaginal extracellular matrix metalloproteinase inducer (EMMPRIN) and matrix metalloproteinase (MMP-8) in vaginal secretions in relation to the composition of vaginal bacterial communities and D- and L-lactic acid levels. The composition of vaginal bacterial communities in 46 women was determined by pyrosequencing the V1 to V3 region of 16S rRNA genes. Lactobacilli were dominant in 71.3% of the women, followed by Gardnerella (17.4%), Streptococcus (8.7%), and Enterococcus (2.2%). Of the lactobacillus-dominated communities, 51.5% were dominated by Lactobacillus crispatus, 36.4% by Lactobacillus iners, and 6.1% each by Lactobacillus gasseri and Lactobacillus jensenii. Concentrations of L-lactic acid were slightly higher in lactobacillus-dominated vaginal samples, but most differences were not statistically significant. D-Lactic acid levels were higher in samples containing L. crispatus than in those with L. iners (P<0.0001) or Gardnerella (P=0.0002). The relative proportion of D-lactic acid in vaginal communities dominated by species of lactobacilli was in concordance with the proportions found in axenic cultures of the various species grown in vitro. Levels of L-lactic acid (P<0.0001) and the ratio of L-lactic acid to D-lactic acid (P=0.0060), but not concentrations of D-lactic acid, were also correlated with EMMPRIN concentrations. Moreover, vaginal concentrations of EMMPRIN and MMP-8 levels were highly correlated (P<0.0001). Taken together, the data suggest the relative proportion of L- to D-lactic acid isomers in the vagina may influence the extent of local EMMPRIN production and subsequent induction of MMP-8. The expression of these proteins may help determine the ability of bacteria to transverse the cervix and initiate upper genital tract infections. A large proportion of preterm births (>50%) result from infections caused by bacteria originating in the vagina, which requires that they traverse the cervix. Factors that influence susceptibility to these infections are not well understood; however, there is evidence that matrix metalloproteinase (MMP-8) is known to alter the integrity of the cervix. In this work, we show that concentrations of vaginal extracellular matrix metalloproteinase inducer (EMMPRIN) are influenced by members of the vaginal microbial community and concentrations of D- or L-lactic acid isomers in vaginal secretions. Elevated levels of D-lactic acid and the ratio of D- to L-lactic acid influence EMMPRIN concentrations as well as MMP-8 levels. Thus, isomers of lactic acid may function as signaling molecules that alter host gene expression and influence risk of infection-related preterm birth.
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Verstraete, G; Vandenbussche, L; Kasmi, S; Nuhn, L; Brouckaert, D; Van Renterghem, J; Grymonpré, W; Vanhoorne, V; Coenye, T; De Geest, B G; De Beer, T; Remon, J P; Vervaet, C
2017-08-30
The aim of the present study was to develop thermoplastic polyurethane (TPU)-based intravaginal rings (IVRs) for prophylaxis and treatment of bacterial vaginosis via hot melt extrusion/injection molding. Therefore, different TPU grades were processed in combination with lactic acid or metronidazole, targeting a sustained lactic acid release over a 28day-period and sustained metronidazole release over 4-7days. Hot melt extrusion of lactic acid/TPU combinations required a lower extrusion temperature due to the plasticizing properties of lactic acid, evidenced by the lower glass transition temperature (T g ) and cross-over point (T tanδ = 1 ) values. NIR-chemical imaging data showed a homogenous distribution of lactic acid in TPU matrices at drug loads up to 30% (w/w). The addition of metronidazole did not lower processing temperatures, as the active pharmaceutical ingredient remained crystalline in the TPU matrix. Hydrophobic TPUs with a low ratio between the soft and hard segments (SS/HS ratio) in the polymer structure were suitable carriers for the lactic acid-eluting device over a 28-day period, while hydrophilic TPUs were needed to achieve the required release rate of metronidazole-eluting IVRs. IVRs manufactured with a TPU grade having a higher SS/HS ratio and lactic acid/TPU ratio exhibited a more elastic behavior. The addition of 25% (w/w) metronidazole did not affect the mechanical properties of the IVRs. Hydrophilic TPUs were most prone to biofilm formation by Candida albicans and Staphylococcus aureus, but the incorporation of metronidazole in the device prevented biofilm formation. Based on the drug eluting performance and mechanical tests, a mixture of lactic acid and Tecoflex™ EG-93A (20/80, w/w) and a combination of metronidazole and Tecophilic™ SP-93A-100 (25/75, w/w) were selected to design IVRs for the prophylaxis and treatment of bacterial vaginosis, respectively. Slug mucosal irritation tests predicted low irritation potency for both devices. Copyright © 2017 Elsevier B.V. All rights reserved.
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Mack, Nzinga; Mazzio, Elizabeth A; Bauer, David; Flores-Rozas, Hernan; Soliman, Karam F A
2017-03-01
In the US, African Americans have a high death rate from triple-negative breast cancer (TNBC), characterized by lack of hormone receptors (ER, PR, HER2/ERRB2) which are otherwise valuable targets of chemotherapy. There is a need to identify novel targets that negatively impact TNBC tumorigenesis. TNBCs release an abundance of lactic acid, under normoxic, hypoxic and hyperoxic conditions; this referred to as the Warburg effect. Accumulated lactic acid sustains peri-cellular acidity which propels metastatic invasion and malignant aggressive transformation. The source of lactic acid is believed to be via conversion of pyruvate by lactate dehydrogenase (LDH) in the last step of glycolysis, with most studies focusing on the LDHA isoform. In this study, LDHA was silenced using long-term MISSION® shRNA lentivirus in human breast cancer MDA-MB-231 cells. Down-regulation of LDHA transcription and protein expression was confirmed by western blot, immunocytochemistry and qPCR. A number of parameters were measured in fully viable vector controls versus knock-down (KD) clones, including levels of lactic acid produced, glucose consumed, ATP and basic metabolic rates. The data show that lentivirus V-165 generated a knock-down clone most effective in reducing both gene and protein levels to less than 1% of vector controls. Stable KD showed absolutely no changes in cell viability, lactic acid production, ATP, glucose consumption or basic metabolic rate. Given the complete absence of impact on any observed parameter by LDH-A KD and this being somewhat contrary to findings in the literature, further analysis was required to determine why. Whole-transcriptome analytic profile on MDA-MB-231 for LDH subtypes using Agilent Human Genome 4×44k microarrays, where the data show the following component breakdown. Transcripts: 30.47 % LDHA, 69.36% LDHB, 0.12% LDHC and 0.05% LDHD. These findings underscore the importance of alternative isoforms of LDH in cancer cells to produce lactic acid, when LDHA is silenced or inhibited. LDHA silencing alone is not effective in hampering or inducing changes in survival, metabolism or lactic acid produced in a cell line with high concentrations of LDHB. Future research will be required to confirm effects of dual LDHA/B knockdown and further confirm that the sole source of lactic acid produced occurs through LDH (all isoforms) in breast cancer cells. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.
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Study of mixed Ca-Zn hydroxyapatite surface modified by lactic acid
NASA Astrophysics Data System (ADS)
Turki, Thouraya; Aissa, Abdallah; Bac, Christophe Goze; Rachdi, Férid; Debbabi, Mongi
2012-07-01
The new hybrid inorganic-organic composites, Ca(10-x)Znx(PO4)6(OH)2-lactic acid, at different amounts of zinc and lactic acid were prepared by dissolution of the organic compound in an hydroxyapatite suspension. They were characterized by XRD, IR, MAS NMR (13C and 1H) and chemical analysis. The crystallinity was slightly affected by the presence of organic fragments. IR and (13C and 1H) MAS NMR measurements indicate that the carboxylic groups of the acid interact with calcium and zinc ions of hydroxyapatite surface. Chemical analysis displays that zinc promotes the acid grafting. A mechanism of surface modification is proposed based on the obtained results.
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Mohd Adnan, Ahmad Faris; Tan, Irene K P
2007-05-01
Two traditional fermented food 'tapai' (fermented tapioca) and 'tempoyak' (fermented durian flesh), chilli puree and fresh goat's milk were used as sources for the isolation of lactic acid bacteria (LAB). A total of 126 isolates were obtained and by sequential screening for catalase activity and Gram-staining, 55 were determined to be LAB out of which 16 were established to be homofermentative by the gel plug test. Seven isolates were identified by use of the API 50CHL kit and two lactobacilli strains and one lactococci strain were selected to study their growth and lactic acid production profiles in a time course experiment. The lactobacilli strains, both isolated from 'tapai', produced higher amounts of cells and lactic acid from glucose as compared to the lactococci strain isolated from fresh goat's milk.
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Glušac, J; Stijepić, M; Đurđević-Milošević, D; Milanović, S; Kanurić, K; Vukić, V
2015-01-01
The ability of whey protein concentrate (WPC) (1% w/v) and/or honey (2% and 4% w⁄v) to improve lactic acid bacteria (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus) growth and viability in yoghurt during a 21 day period of storage was investigated. Another focus of this study was to examine fermentation kinetics and post-acidification rates through pH and lactic acid content measurements over the 21 day period. The addition of WPC and acacia honey accelerated fermentation and improved lactic acid bacteria (LAB) growth over the 21 days, but honey proportion did not significantly affect the viability of LAB. Moreover, adding honey and WPC did not support the overproduction of lactic acid, which positively influenced yoghurt stability during the 21 day storage period.
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Ouyang, Jia; Ma, Rui; Zheng, Zhaojuan; Cai, Cong; Zhang, Min; Jiang, Ting
2013-05-01
Highly efficient L-lactate production by a thermophilic strain Bacillus sp. NL01 was demonstrated in this study. Lignocellulosic hydrolyzates containing a high content of glucose, which was prepared from corn stover, was used as substrate for L-lactic acid production. The fermentation was carried out under open condition without sterilization and used NaOH as alkaline neutralizing reagent. In batch fermentation, 56.37 g l(-1) L-lactic acid was obtained from lignocellulosic hydrolyzates which contained the solid residues produced in enzymatic saccharification. In fed-batch fermentation, 75.03 g l(-1) L-lactic acid was obtained from lignocellulosic hydrolyzates supernatant. The yield was 74.5% and the average productivity was 1.04 g l(-1) h(-1). Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.
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USDA-ARS?s Scientific Manuscript database
Without the addition of preservative compounds cucumbers acidified with 150 mM acetic acid with pH adjusted to 3.5 typically undergo fermentation by lactic acid bacteria. Fumaric acid (20 mM) inhibited growth of Lactobacillus plantarum and the lactic acid bacteria present on fresh cucumbers, but sp...
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Liu, Ke; Zeng, Xiangmiao; Qiao, Lei; Li, Xisheng; Yang, Yubo; Dai, Cuihong; Hou, Aiju; Xu, Dechang
2014-01-01
The excessive production of lactic acid by L. bulgaricus during yogurt storage is a phenomenon we are always tried to prevent. The methods used in industry either control the post-acidification inefficiently or kill the probiotics in yogurt. Genetic methods of changing the activity of one enzyme related to lactic acid metabolism make the bacteria short of energy to growth, although they are efficient ways in controlling lactic acid production. A model of pH-induced promoter regulation on the production of lactic acid by L. bulgaricus was built. The modelled lactic acid metabolism without pH-induced promoter regulation fitted well with wild type L. bulgaricus (R2LAC = 0.943, R2LA = 0.942). Both the local sensitivity analysis and Sobol sensitivity analysis indicated parameters Tmax, GR, KLR, S, V0, V1 and dLR were sensitive. In order to guide the future biology experiments, three adjustable parameters, KLR, V0 and V1, were chosen for further simulations. V0 had little effect on lactic acid production if the pH-induced promoter could be well induced when pH decreased to its threshold. KLR and V1 both exhibited great influence on the producing of lactic acid. The proposed method of introducing a pH-induced promoter to regulate a repressor gene could restrain the synthesis of lactic acid if an appropriate strength of promoter and/or an appropriate strength of ribosome binding sequence (RBS) in lacR gene has been designed.
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Qiu, Zhongyang; Gao, Qiuqiang; Bao, Jie
2017-12-01
Xylose-assimilating pathway was constructed in a d-lactic acid producing Pediococcus acidilactici strain and evolutionary adapted to yield a co-fermentation strain P. acidilactici ZY15 with 97.3g/L of d-lactic acid and xylose conversion of 92.6% obtained in the high solids content simultaneous saccharification and co-fermentation (SSCF) of dry dilute acid pretreated and biodetoxified corn stover feedstock. The heterologous genes encoding xylose isomerase (xylA) and xylulokinase (xylB) were screened and integrated into the P. acidilactici chromosome. The metabolic flux to acetic acid in phosphoketolase pathway was re-directed to pentose phosphate pathway by substituting the endogenous phosphoketolase gene (pkt) with the heterologous transketolase (tkt) and transaldolase (tal) genes. The xylose-assimilating ability of the newly constructed P. acidilactici strain was significantly improved by adaptive evolution. This study provided an important strain and process prototype for high titer d-lactic acid production from lignocellulose feedstock with efficient xylose assimilation. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Liu, Rui; Dai, Lin; Hu, Li-Qiu; Zhou, Wen-Qin; Si, Chuan-Ling
2017-11-01
The need for green renewable alternatives such as lignin to traditional fillers has driven recent interest in polylactic acid blend materials. Herein, lignin-graft-polylactic acid copolymers (LG-g-PDLA, LG-g-PDLLA, and LG-g-PLLA) have been synthesized via ring-opening polymerization of d-, dl-, and l-lactic acid. Then poly(l-lactic acid)/lignin-graft-polylactic acid (PLLA/LG-g-PDLA, /LG-g-PDLLA, and /LG-g-PLLA) complex films have been prepared. The results showed that, compared with LG-g-PDLA and LG-g-PLLA, a small amount of LG-g-PDLA addition could improve the crystallization rate, reduce the glass transition temperature and cold crystallization temperature of PLLA due to the stereocomplex crystallites. The thermal stability, tensile strength and strain of the stereocomplex films were also enhanced. Moreover, the PLLA/LG-g-PDLA films have good ultraviolet resistance and excellent biocompatibility. This study provides a green approach to design advanced polylactic acid-based blends with renewable natural resources. Copyright © 2017 Elsevier B.V. All rights reserved.
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Valík, Ľ; Ačai, P; Liptáková, D
2017-11-01
The growth of the oxidatively imperfect yeast Candida maltosa Komagata, Nakase et Katsuya was studied experimentally and modelled mathematically in relation to sodium benzoate and lactic acid concentrations at different temperatures. Application of gamma models for the growth rate resulted in determination of cardinal temperature parameters for the growth environment containing lactic acid or sodium benzoate (T min = 0·7/1·3°C, T max = 45·3/45·0°C, T opt = 36·1/37·0°C, μ opt = 0·88/0·96 h -1 ) as well as the maximal lactic acid concentration for growth (1·9%) or sodium benzoate (1397 mg kg -1 ). Based on the model, the times to reach the density of C. maltosa at the level of 10 5 CFU per ml can be determined at each combination of storage temperature and preservative concentration. The approach used in this study can broaden knowledge of the microbiological quality of fermented milk products during storage as well as the preservation efficacy of mayonnaise dressing for storage and consumption. The strain of Candida maltosaYP1 was originally isolated from air filters that ensured clean air overpressure in yoghurt fermentation tanks. Its growth in contaminated yoghurts manifested outwardly through surface growth, assimilation lactic acid and slight production of carbon dioxide. This was the opportunity to model the effects of lactic acid and sodium benzoate on growth and predict its behaviour in foods. The approach used in this study provides knowledge about microbiological quality development during storage of the fermented milk products as well as some preserved foods for storage and consumption. © 2017 The Society for Applied Microbiology.
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Adsorption of lactic acid on chiral Pt surfaces—A density functional theory study
NASA Astrophysics Data System (ADS)
Franke, J.-H.; Kosov, D. S.
2013-02-01
The adsorption of the chiral molecule lactic acid on chiral Pt surfaces is studied by density functional theory calculations. First, we study the adsorption of L-lactic acid on the flat Pt(111) surface. Using the optimed PBE - van der Waals (oPBE-vdW) functional, which includes van der Waals forces on an ab initio level, it is shown that the molecule has two binding sites, a carboxyl and the hydroxyl oxygen atoms. Since real chiral surfaces are (i) known to undergo thermal roughening that alters the distribution of kinks and step edges but not the overall chirality and (ii) kink sites and edge sites are usually the energetically most favored adsorption sites, we focus on two surfaces that allow qualitative sampling of the most probable adsorption sites. We hereby consider chiral surfaces exhibiting (111) facets, in particular, Pt(321) and Pt(643). The binding sites are either both on kink sites—which is the case for Pt(321) or on one kink site—as on Pt(643). The binding energy of the molecule on the chiral surfaces is much higher than on the Pt(111) surface. We show that the carboxyl group interacts more strongly than the hydroxyl group with the kink sites. The results indicate the possible existence of very small chiral selectivities of the order of 20 meV for the Pt(321) and Pt(643) surfaces. L-lactic acid is more stable on Pt(321)S than D-lactic acid, while the chiral selectivity is inverted on Pt(643)S. The most stable adsorption configurations of L- and D-lactic acid are similar for Pt(321) but differ for Pt(643). We explore the impact of the different adsorption geometries on the work function, which is important for field ion microscopy.
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[Modeling of lactic acid fermentation of leguminous plant juices].
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.
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In vitro metabolism of radiolabeled carbohydrates by protective cecal anaerobic bacteria.
Hume, M E; Beier, R C; Hinton, A; Scanlan, C M; Corrier, D E; Peterson, D V; DeLoach, J R
1993-12-01
Cecal anaerobic bacteria from adult broilers were cultured in media containing .25% glucose or .25% lactose. Media also contained either [14C]-labeled lactose, glucose, galactose, or lactic acid as metabolic tracers. Cultures were analyzed at 4, 8, and 12 h for pH, radiolabeled and unlabeled volatile fatty acids, and lactic acid. The pH values of cultures containing .25% lactose were significantly (P < .05) higher than the pH values of cultures containing .25% glucose. Lactose cultures reached their lowest pH more slowly than glucose cultures. Concentrations of unlabeled volatile fatty acids increased and lactic acid decreased during incubation of the cultures. Radiolabeled sugars and lactic acid were more readily metabolized to volatile fatty acids in media containing lactose than in media containing glucose. The preferred metabolism of [14C]substrates, independent of media carbohydrate, was in the following order: lactic acid > galactose, lactose > glucose. The volatile fatty acids in which radiolabel was most concentrated were acetic acid, propionic acid, or butyric acid.
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L-Lactic Acid Production by Lactobacillus rhamnosus ATCC 10863
Senedese, Ana Lívia Chemeli; Maciel Filho, Rubens; Maciel, Maria Regina Wolf
2015-01-01
Lactic acid has been shown to have the most promising application in biomaterials as poly(lactic acid). L. rhamnosus ATCC 10863 that produces L-lactic acid was used to perform the fermentation and molasses was used as substrate. A solution containing 27.6 g/L of sucrose (main composition of molasses) and 3.0 g/L of yeast extract was prepared, considering the final volume of 3,571 mL (14.0% (v/v) inoculum). Batch and fed batch fermentations were performed with temperature of 43.4°C and pH of 5.0. At the fed batch, three molasses feed were applied at 12, 24, and 36 hours. Samples were taken every two hours and the amounts of lactic acid, sucrose, glucose, and fructose were determined by HPLC. The sucrose was barely consumed at both processes; otherwise the glucose and fructose were almost entirely consumed. 16.5 g/L of lactic acid was produced at batch and 22.0 g/L at fed batch. Considering that lactic acid was produced due to the low concentration of the well consumed sugars, the final amount was considerable. The cell growth was checked and no substrate inhibition was observed. A sucrose molasses hydrolysis is suggested to better avail the molasses fermentation with this strain, surely increasing the L-lactic acid. PMID:25922852
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Michelz Beitel, Susan; Fontes Coelho, Luciana; Sass, Daiane Cristina
2017-01-01
The interest in the production of lactic acid has increased due to its wide range of applications. In the present study, the variables that affect fermentative D(−) lactic acid production were investigated: neutralizing agents, pH, temperature, inoculum percentage, agitation, and concentration of the medium components. An experimental design was applied to determine the optimal concentrations of the medium components and fermentation was studied using different feeding strategies. High production (122.41 g/L) and productivity (3.65 g/L·h) were efficiently achieved by Sporolactobacillus nakayamae in 54 h using a multipulse fed-batch technique with an initial medium containing 35 g/L of yeast extract (byproduct of alcohol production), 60 g/L of crystallized sugar, and 7.5 mL/L of salts. The fermentation process was conducted at 35°C and pH 6.0 controlled by NaOH with a 20% volume of inoculum and agitation at 125 rpm. The production of a high optically pure concentration of D(−) lactic acid combined with an environmentally friendly NaOH-based process demonstrates that S. nakayamae is a promising strain for D(−) lactic acid production. PMID:29081803
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NASA Astrophysics Data System (ADS)
de Carvalho Gomes, Rafael; Seruff, Luciana Amaral; Scal, Maira Labanca Waineraich; Vera, Ysrael Marrero
2018-02-01
The separation of rare earth elements (REEs) using solvent extraction adding complexing agents appears to be an alternative to saponification of the extractant. We evaluated the effect of lactic acid concentration on didymium (praseodymium and neodymium) and lanthanum extraction with 2-ethylhexyl phosphonic acid mono-2-ethyl hexyl ester [HEH(EHP)] as extractant. First, we investigated in batch experiments the separation of lanthanum (La) and didymium (Pr and Nd) using McCabe-Thiele diagrams to estimate the number of extraction stages when the feed solution was or was not conditioned with lactic acid. Additionally, we conducted continuous liquid-liquid extraction experiments and evaluated the influence of lactic acid concentration on the REE extraction and separation. The tests showed that the extraction percentage of REEs and the separation factor Pr/La increased when the lactic acid concentration increased, but the didymium purity decreased. Lanthanum, praseodymium, and neodymium extraction rate were 23.0, 89.7, and 99.2 pct, respectively, with 1:1 aqueous/organic volume flow rate and feed solution doped with 0.52 mol L-1 lactic acid. The highest didymium purity reached was 92.0 pct with 0.26 mol L-1 lactic acid concentration.
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Ye, Lidan; Hudari, Mohammad Sufian Bin; Zhou, Xingding; Zhang, Dongxu; Li, Zhi; Wu, Jin Chuan
2013-06-01
Cost-effective conversion of lignocellulose hydrolysate to optically pure lactic acid is commercially attractive but very challenging. Bacillus coagulans JI12 was isolated from natural environment and used to produce L-lactic acid (optical purity > 99.5 %) from lignocellulose sugars and acid hydrolysate of oil palm empty fruit bunch (EFB) at 50 °C and pH 6.0 without sterilization of the medium. In fed-batch fermentation with 85 g/L initial xylose and 55 g/L xylose added after 7.5 h, 137.5 g/L lactic acid was produced with a yield of 98 % and a productivity of 4.4 g/L h. In batch fermentation of a sugar mixture containing 8.5 % xylose, 1 % glucose, and 1 % L-arabinose, the lactic acid yield and productivity reached 98 % and 4.8 g/L h, respectively. When EFB hydrolysate was used, 59.2 g/L of lactic acid was produced within 9.5 h at a yield of 97 % and a productivity of 6.2 g/L h, which are the highest among those ever reported from lignocellulose hydrolysates. These results indicate that B. coagulans JI12 is a promising strain for industrial production of L-lactic acid from lignocellulose hydrolysate.
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Zhang, Jie; Guo, Gang; Chen, Lei; Li, Junfeng; Yuan, Xianjun; Yu, Chengqun; Shimojo, Masataka; Shao, Tao
2015-06-01
The objective of this study was to evaluate effects of lactic acid bacteria and propionic acid on the fermentation quality and aerobic stability of oats-common vetch mixed silage by using a small-scale fermentation system on the Tibetan plateau. (i) An inoculant (Lactobacillus plantarum) (L) or (ii) propionic acid (P) or (iii) inoculant + propionic acid (PL) were used as additives. After fermenting for 60 days, silos were opened and the aerobic stability was tested for the following 15 days. The results showed that all silages were well preserved with low pH and NH3 -N, and high lactic acid content and V-scores. L and PL silages showed higher (P < 0.05) lactic acid and crude protein content than the control silage. P silage inhibited lactic acid production. Under aerobic conditions, L silage had similar yeast counts as the control silage (> 10(5) cfu/g fresh matter (FM)); however, it numerically reduced aerobic stability for 6 h. P and PL silages showed fewer yeasts (< 10(5) cfu/g FM) (P < 0.05) and markedly improved the aerobic stability (> 360 h). The result suggested that PL is the best additive as it could not only improved fermentation quality, but also aerobic stability of oats-common vetch mixed silage on the Tibetan plateau. © 2014 Japanese Society of Animal Science.
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Chirped-Pulse Ftmw Spectroscopy of the Lactic ACID-H_2O System
NASA Astrophysics Data System (ADS)
Kisiel, Zbigniew; Białkowska-Jaworska, Ewa; Zaleski, Daniel P.; Neill, Justin L.; Steber, Amanda L.; Pate, Brooks H.
2011-06-01
The previous study of the rotational spectrum of lactic acid in supersonic expansion revealed rather temperamental behaviour of signal intensity suggestive of considerable clusterization. Lactic acid samples contain an appreciable amount of water so that the presence of clusters with water, as well as lactic dimers is suspected. Several, mainly computational, studies of such species have already been published. Investigation of the chirped-pulse rotational spectrum of a heated lactic acid (LA) sample diluted in Ne carrier gas allowed unambiguous assignment of the LA-H_2O, LA-(H_2O)_2, and LA-(H_2O)_3 species. In addition, the rotational spectrum of the AaT conformer of lactic acid has been assigned. This conformer involves an intramolecular hydrogen bond to the hydroxyl of the carboxylic group and it has been estimated to be less stable by ca 10 kJ/mol than the most stable SsC conformer. The evidence for the assignment and a discussion of the derived properties for the new species are presented. L.Pszczółkowski, E.Białkowska-Jaworska, Z.Kisiel, J. Mol. Spectrosc. 234, 106 (2005). J.Sadlej, J.Cz.Dobrowolski, J.E.Rode, M.H.Jamróz, PCCP 8, 101 (2006) M.Losada, H.Tran, Y.Xu, J. Chem. Phys. 128, 014508 (2008) A.Smaga, J.Sadlej, J. Phys. Chem. A 114, 4427 (2010). A.Borba, A.Gomez-Zavaglia, L.Łapinski, R.Fausto, PCCP 6, 2101 (2004).
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Papagaroufalis, Konstantinos; Fotiou, Aikaterini; Egli, Delphine; Tran, Liên-Anh; Steenhout, Philippe
2014-01-01
BACKGROUND d-Lactic acidosis in infants fed lactic acid bacteria-containing products is a concern. METHODS The primary objective of this non-inferiority trial was to compare urinary d-lactic acid concentrations during the first 28 days of life in infants fed formula containing Lactobacillus reuteri (1.2 × 106 colony forming units (CFU)/ml) with those fed a control formula. The non-inferiority margin was set at a two-fold increase in d-lactic acid (0.7 mmol/mol creatinine, log-transformed). Healthy term infants in Greece were enrolled between birth and 72 hours of age, and block randomized to a probiotic (N = 44) or control (N = 44) group. They were exclusively fed their formulae until 28 days of age and followed up at 7, 14, 28, 112, and 168 ± 3 days. Anthropometric measurements were taken at each visit and tolerance recorded until 112 days. Urine was collected before study formula intake and at all visits up to 112 days and blood at 14 days. RESULTS d-Lactic acid concentration in the probiotic group was below the non-inferiority margin at 28 days: treatment effect −0.03 (95% confidence interval [CI]: [−0.48 to 0.41]) mmol/mol creatinine but was above the non-inferiority margin at 7 and 14 days—treatment effect 0.50 (95% CI: [0.05–0.96]) mmol/mol creatinine and 0.45 (95% CI: [0.00–0.90]) mmol/mol creatinine, respectively. Blood acid excess and pH, anthropometry, tolerance, and adverse events (AEs) were not significantly different between groups. CONCLUSION Intake of L. reuteri-containing formula was safe and did not cause an increase in d-lactic acid beyond two weeks. PMID:24812520
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Papagaroufalis, Konstantinos; Fotiou, Aikaterini; Egli, Delphine; Tran, Liên-Anh; Steenhout, Philippe
2014-01-01
d-Lactic acidosis in infants fed lactic acid bacteria-containing products is a concern. The primary objective of this non-inferiority trial was to compare urinary d-lactic acid concentrations during the first 28 days of life in infants fed formula containing Lactobacillus reuteri (1.2 × 10(6) colony forming units (CFU)/ml) with those fed a control formula. The non-inferiority margin was set at a two-fold increase in d-lactic acid (0.7 mmol/mol creatinine, log-transformed). Healthy term infants in Greece were enrolled between birth and 72 hours of age, and block randomized to a probiotic (N = 44) or control (N = 44) group. They were exclusively fed their formulae until 28 days of age and followed up at 7, 14, 28, 112, and 168 ± 3 days. Anthropometric measurements were taken at each visit and tolerance recorded until 112 days. Urine was collected before study formula intake and at all visits up to 112 days and blood at 14 days. d-Lactic acid concentration in the probiotic group was below the non-inferiority margin at 28 days: treatment effect -0.03 (95% confidence interval [CI]: [-0.48 to 0.41]) mmol/mol creatinine but was above the non-inferiority margin at 7 and 14 days-treatment effect 0.50 (95% CI: [0.05-0.96]) mmol/mol creatinine and 0.45 (95% CI: [0.00-0.90]) mmol/mol creatinine, respectively. Blood acid excess and pH, anthropometry, tolerance, and adverse events (AEs) were not significantly different between groups. Intake of L. reuteri-containing formula was safe and did not cause an increase in d-lactic acid beyond two weeks.
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Stimulation of Lactic Acid Bacteria by a Micrococcus Isolate: Evidence for Multiple Effects
Nath, K. R.; Wagner, B. J.
1973-01-01
Growth of, and rate of acid production by, six cultures of lactic acid bacteria were increased in the presence of Micrococcus isolate F4 or a preparation of its capsular material. Concentrations of hydrogen peroxide found in pure cultures of the lactic acid bacteria were not detectable, or were greatly reduced, in mixed culture with Micrococcus isolate F4. The capsular material was not as effective as whole cells in preventing accumulation of H2O2. Catalase stimulated growth of, and the rate of acid production by, the lactic acid bacteria, but not to the same extent as Micrococcus isolate F4 in some cultures. The existence of two mechanisms for micrococcal stimulation of the lactic acid bacteria is postulated. One mechanism involves removal of H2O2; the other has not been characterized. PMID:4199337
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Witkin, Steven S.; Mendes-Soares, Helena; Linhares, Iara M.; Jayaram, Aswathi; Ledger, William J.; Forney, Larry J.
2013-01-01
ABSTRACT We evaluated levels of vaginal extracellular matrix metalloproteinase inducer (EMMPRIN) and matrix metalloproteinase (MMP-8) in vaginal secretions in relation to the composition of vaginal bacterial communities and d- and l-lactic acid levels. The composition of vaginal bacterial communities in 46 women was determined by pyrosequencing the V1 to V3 region of 16S rRNA genes. Lactobacilli were dominant in 71.3% of the women, followed by Gardnerella (17.4%), Streptococcus (8.7%), and Enterococcus (2.2%). Of the lactobacillus-dominated communities, 51.5% were dominated by Lactobacillus crispatus, 36.4% by Lactobacillus iners, and 6.1% each by Lactobacillus gasseri and Lactobacillus jensenii. Concentrations of l-lactic acid were slightly higher in lactobacillus-dominated vaginal samples, but most differences were not statistically significant. d-Lactic acid levels were higher in samples containing L. crispatus than in those with L. iners (P < 0.0001) or Gardnerella (P = 0.0002). The relative proportion of d-lactic acid in vaginal communities dominated by species of lactobacilli was in concordance with the proportions found in axenic cultures of the various species grown in vitro. Levels of l-lactic acid (P < 0.0001) and the ratio of l-lactic acid to d-lactic acid (P = 0.0060), but not concentrations of d-lactic acid, were also correlated with EMMPRIN concentrations. Moreover, vaginal concentrations of EMMPRIN and MMP-8 levels were highly correlated (P < 0.0001). Taken together, the data suggest the relative proportion of l- to d-lactic acid isomers in the vagina may influence the extent of local EMMPRIN production and subsequent induction of MMP-8. The expression of these proteins may help determine the ability of bacteria to transverse the cervix and initiate upper genital tract infections. PMID:23919998
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Lactobacilli Inactivate Chlamydia trachomatis through Lactic Acid but Not H2O2
Gong, Zheng; Luna, Yesmin; Yu, Ping; Fan, Huizhou
2014-01-01
Lactobacillus species dominate the microbiome in the lower genital tract of most reproductive-age women. Producing lactic acid and H2O2, lactobacilli are believed to play an important role in prevention of colonization by and growth of pathogens. However, to date, there have been no reported studies characterizing how lactobacilli interact with Chlamydia trachomatis, a leading sexually transmitted bacterium. In this report, we demonstrate inactivation of C. trachomatis infectivity by culture media conditioned by Lactobacillus crispatus, L. gasseri and L. jensenii, known to be dominating organisms in the human vaginal microbiome. Lactobacillus still cultures produced lactic acid, leading to time- and concentration-dependent killing of C. trachomatis. Neutralization of the acidic media completely reversed chlamydia killing. Addition of lactic acid into Lactobacillus-unconditioned growth medium recapitulated the chlamydiacidal activity of conditioned media. The H2O2 concentrations in the still cultures were found to be comparable to those reported for the cervicovaginal fluid, but insufficient to inactivate chlamydiae. Aeration of Lactobacillus cultures by shaking markedly induced H2O2 production, but strongly inhibited Lactobacillus growth and lactic acid production, and thus severely affected acidification, leading to significantly reduced chlamydiacidal efficiency. These observations indicate lactobacilli inactivate chlamydiae primarily through maintaining acidity in a relatively hypoxic environment in the vaginal lumen with limited H2O2, which is consistent with the notion that women with higher vaginal pH are more prone to sexually transmitted C. trachomatis infection. In addition to lactic acid, formic acid and acetic acid also exhibited potent chlamydiacidal activities. Taken together, our findings imply that lowering the vaginal pH through engineering of the vaginal microbiome and other means will make women less susceptible to C. trachomatis infection. PMID:25215504
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Okano, Kenji; Hama, Shinji; Kihara, Maki; Noda, Hideo; Tanaka, Tsutomu; Kondo, Akihiko
2017-03-01
Simultaneous saccharification and fermentation (SSF) of D-lactic acid was performed using brown rice as both a substrate and a nutrient source. An engineered Lactobacillus plantarum NCIMB 8826 strain, in which the ʟ-lactate dehydrogenase gene was disrupted, produced 97.7 g/L D-lactic acid from 20% (w/v) brown rice without any nutrient supplementation. However, a significant amount of glucose remained unconsumed and the yield of lactic acid was as low as 0.75 (g/g-glucose contained in brown rice). Interestingly, the glucose consumption was significantly improved by adapting L. plantarum cells to the low-pH condition during the early stage of SSF (8-17 h). As a result, 117.1 g/L D-lactic acid was produced with a high yield of 0.93 and an optical purity of 99.6% after 144 h of fermentation. SSF experiments were repeatedly performed for ten times and D-lactic acid was stably produced using recycled cells (118.4-129.8 g/L). On average, D-lactic acid was produced with a volumetric productivity of 2.18 g/L/h over 48 h.
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Production of lactic acid from sucrose: strain selection, fermentation, and kinetic modeling.
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.
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Code of Federal Regulations, 2014 CFR
2014-04-01
... lactose is converted to lactic acid, or from the curd formation by direct acidification of milk, is known... lactic acid is known as sweet whey. Sweet whey has a maximum titratable acidity of not more than 0.16 percent, calculated as lactic acid, and an alkalinity of ash of not more than 225 milliliters of 0.1N...
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Code of Federal Regulations, 2013 CFR
2013-04-01
... a significant amount of lactose is converted to lactic acid, or from the curd formation by direct... conversion of lactose to lactic acid is known as sweet whey. Sweet whey has a maximum titratable acidity of not more than 0.16 percent, calculated as lactic acid, and an alkalinity of ash of not more than 225...
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Code of Federal Regulations, 2012 CFR
2012-04-01
... a significant amount of lactose is converted to lactic acid, or from the curd formation by direct... conversion of lactose to lactic acid is known as sweet whey. Sweet whey has a maximum titratable acidity of not more than 0.16 percent, calculated as lactic acid, and an alkalinity of ash of not more than 225...
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Li, Qingxin; Hudari, Mohammad Sufian Bin; Wu, Jin Chuan
2016-01-01
Optically pure D-lactic acid was produced from glucose, xylose, or starch by the combined use of Weissella sp. S26 and Bacillus sp. ADS3, two native bacterial strains isolated from Singapore environment. Weissella sp. S26 was used to ferment various sugars to lactic acid rich in D-isomer followed by sterilization of the broth and inoculation of Bacillus sp. ADS3 cells to selectively degrade acetic acid (if any) and L-lactic acid. In a simultaneous saccharification and fermentation of starch by Weissella sp. S26 in 1 L of modified MRS medium containing 50 g/L starch at 30 °C, lactic acid reached 24.2 g/L (23.6 g/L of D-isomers and 0.6 g/L of L-isomers), and acetic acid was 11.8 g/L at 37 h. The fermentation broth was sterilized at 100 °C for 20 min and cooled down to 30 °C followed by inoculation of Bacillus sp. ADS3 (10 %, v/v), and the mixture was kept at 30 °C for 115 h. Acetic acid was completely removed, and L-lactic acid was largely removed giving an optical purity of D-lactic acid as high as 99.5 %.
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Leisner, J J; Vancanneyt, M; Goris, J; Christensen, H; Rusul, G
2000-01-01
Paralactobacillus selangorensis gen. nov., sp. nov. is described. This organism, isolated from a Malaysian food ingredient called chili bo, is an obligatory homofermentative, rod-shaped lactic acid bacterium. The G+C content is 46.1-46.2+/-0.3 mol%. Earlier 16S rRNA studies showed that this organism constitutes a new taxon distantly related to the Lactobacillus casei-Pediococcus group. A phenotypic description that distinguishes Paralactobacillus selangorensis from other genera of lactic acid bacteria is presented. The type strain of Paralactobacillus selangorensis is LMG 17710T.
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Liguori, Rossana; Soccol, Carlos Ricardo; Vandenberghe, Luciana Porto de Souza; Woiciechowski, Adenise Lorenci; Ionata, Elena; Marcolongo, Loredana; Faraco, Vincenza
2015-01-01
Six Lactobacillus strains were analyzed to select a bacterium for conversion of brewers' spent grain (BSG) into lactic acid. Among the investigated strains, L. acidophilus ATCC 43121 showed the highest yield of lactic acid production (16.1 g/L after 48 hours) when grown in a synthetic medium. It was then analyzed for its ability to grow on the hydrolysates obtained from BSG after acid-alkaline (AAT) or aqueous ammonia soaking (AAS) pretreatment. The lactic acid production by L. acidophilus ATCC 43121 through fermentation of the hydrolysate from AAS treated BSG was 96% higher than that from the AAT treated one, although similar yields of lactic acid per consumed glucose were achieved due to a higher (46%) glucose consumption by L. acidophilus ATCC 43121 in the AAS BSG hydrolysate. It is worth noting that adding yeast extract to the BSG hydrolysates increased both the yield of lactic acid per substrate consumed and the volumetric productivity. The best results were obtained by fermentation of AAS BSG hydrolysate supplemented by yeast extract, in which the strain produced 22.16 g/L of lactic acid (yield of 0.61 g/g), 27% higher than the value (17.49 g/L) obtained in the absence of a nitrogen source. PMID:26640784
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Characterization of Lactic Acid Bacteria (LAB) isolated from Indonesian shrimp paste (terasi)
NASA Astrophysics Data System (ADS)
Amalia, U.; Sumardianto; Agustini, T. W.
2018-02-01
Shrimp paste was one of fermented products, popular as a taste enhancer in many dishes. The processing of shrimp paste was natural fermentation, depends on shrimp it self and the presence of salt. The salt inhibits the growth of undesirable microorganism and allows the salt-tolerant lactic acid bacteria (LAB) to ferment the protein source to lactic acids. The objectives of this study were to characterize LAB isolated from Indonesian shrimp paste or "Terasi" with different times of fermentation (30, 60 and 90 days). Vitech analysis showed that there were four strains of the microorganism referred to as lactic acid bacteria (named: LABS1, LABS2, LABS3 and LABS4) with 95% sequence similarity. On the basis of biochemical, four isolates represented Lactobacillus, which the name Lactobacillus plantarum is proposed. L.plantarum was play role in resulting secondary metabolites, which gave umami flavor in shrimp paste.
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Effects of sodium citrate, citric acid and lactic acid on human blood coagulation.
Scaravilli, Vittorio; Di Girolamo, Luca; Scotti, Eleonora; Busana, Mattia; Biancolilli, Osvaldo; Leonardi, Patrizia; Carlin, Andrea; Lonati, Caterina; Panigada, Mauro; Pesenti, Antonio; Zanella, Alberto
2018-05-01
Citric acid infusion in extracorporeal blood may allow concurrent regional anticoagulation and enhancement of extracorporeal CO 2 removal. Effects of citric acid on human blood thromboelastography and aggregometry have never been tested before. In this in vitro study, citric acid, sodium citrate and lactic acid were added to venous blood from seven healthy donors, obtaining concentrations of 9 mEq/L, 12 mEq/L and 15 mEq/L. We measured gas analyses, ionized calcium (iCa ++ ) concentration, activated clotting time (ACT), thromboelastography and multiplate aggregometry. Repeated measure analysis of variance was used to compare the acidifying and anticoagulant properties of the three compounds. Sodium citrate did not affect the blood gas analysis. Increasing doses of citric and lactic acid progressively reduced pH and HCO 3 - and increased pCO 2 (p<0.001). Sodium citrate and citric acid similarly reduced iCa ++ , from 0.39 (0.36-0.39) and 0.35 (0.33-0.36) mmol/L, respectively, at 9 mEq/L to 0.20 (0.20-0.21) and 0.21 (0.20-0.23) mmol/L at 15 mEq/L (p<0.001). Lactic acid did not affect iCa ++ (p=0.07). Sodium citrate and citric acid similarly incremented the ACT, from 234 (208-296) and 202 (178-238) sec, respectively, at 9 mEq/L, to >600 sec at 15 mEq/L (p<0.001). Lactic acid did not affect the ACT values (p=0.486). Sodium citrate and citric acid similarly incremented R-time and reduced α-angle and maximum amplitude (MA) (p<0.001), leading to flat-line thromboelastograms at 15 mEq/L. Platelet aggregometry was not altered by any of the three compounds. Citric acid infusions determine acidification and anticoagulation of blood similar to lactic acid and sodium citrate, respectively.
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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.
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D-lactic acid measurements in the diagnosis of bacterial infections.
Smith, S M; Eng, R H; Campos, J M; Chmel, H
1989-01-01
Body fluids suspected of bacterial infection were cultured and examined for the presence of D-lactic acid, a specific bacterial metabolite. We examined 206 patients and 264 specimens. D-Lactic acid was found in concentrations of greater than or equal to 0.15 mM in 11 of 11 infected and 6 of 40 noninfected ascitic fluids, 6 of 6 infected and 4 of 33 noninfected pleural fluids, 4 of 4 infected and 0 of 13 noninfected synovial fluids, and 26 of 27 infected and 2 of 130 noninfected cerebrospinal fluids. The overall sensitivity was 79.7%, and the specificity was 99.5% when the D-lactic acid concentration was at least 0.15 mM. The most important clinical utility of the D-lactic acid measurement appears to be for patients with bacterial infection in various body compartments and in patients who have already received antimicrobial therapy. An elevation in D-lactic acid may indicate the presence of bacterial infection even when cultures are negative. PMID:2715313
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Review - Lactic acid bacteria in traditional fermented Asian foods.
Azam, Mariya; Mohsin, Mashkoor; Ijaz, Hira; Tulain, Ume Ruqia; Ashraf, Muhammad Adnan; Fayyaz, Ahad; Abadeen, Zainul; Kamran, Qindeel
2017-09-01
Lactic acid bacteria play vital roles in various fermented foods in Asia. This paper reviews many types of the world's lactic acid fermented foods and discusses the beneficial effects of lactic acid fermentation of food. The lactic acid bacteria associated with foods now include species of the genera Carnobacterium, Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Oenococcus, Pediococcus, Streptococcus, Tetragenococcus, Vagococcus and Weissella. Lactic acid bacteria (LAB) are involved in many fermentation processes of Asian traditional foods, demonstrating their profound effects on improving food quality and food safety. During the past few decades' interest has arisen in the use of the varied antagonistic activities of LAB to extent the shelf-life of protein-rich products such as meats and fish. This review article outlines the main types of LAB fermentation as well as their typical fermented foods such as idli, kishk, sauerkraut, koumiss, Suan-tsai, stinky tofu, Chinese sausage and kefir. The roles of LAB and the reasons for their common presence are also discussed.
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USDA-ARS?s Scientific Manuscript database
The attraction of female Aedes aegypti to single compounds and binary compositions comprised of L-lactic acid and an additional saturated compound from a set of ketones, sulfides, and chloroalkanes was studied using a triple-cage dual-port olfactometer. These chemical classes were studied because o...
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Systems solutions by lactic acid bacteria: from paradigms to practice
2011-01-01
Lactic acid bacteria are among the powerhouses of the food industry, colonize the surfaces of plants and animals, and contribute to our health and well-being. The genomic characterization of LAB has rocketed and presently over 100 complete or nearly complete genomes are available, many of which serve as scientific paradigms. Moreover, functional and comparative metagenomic studies are taking off and provide a wealth of insight in the activity of lactic acid bacteria used in a variety of applications, ranging from starters in complex fermentations to their marketing as probiotics. In this new era of high throughput analysis, biology has become big science. Hence, there is a need to systematically store the generated information, apply this in an intelligent way, and provide modalities for constructing self-learning systems that can be used for future improvements. This review addresses these systems solutions with a state of the art overview of the present paradigms that relate to the use of lactic acid bacteria in industrial applications. Moreover, an outlook is presented of the future developments that include the transition into practice as well as the use of lactic acid bacteria in synthetic biology and other next generation applications. PMID:21995776
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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.
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Membrane-mediated extractive fermentation for lactic acid production from cellulosic biomass
DOE Office of Scientific and Technical Information (OSTI.GOV)
Chen, Rongfu; Lee, Y.Y.
1997-12-31
Lactic acid production from cellulosic biomass by cellulose and Lactobacillus delbrueckii was studied in a fermenter-extractor employing a microporous hollow fiber membrane (NIHF). This bioreactor system was operated under a fed-batch mode with continuous removal of lactic acid by an in situ extraction. A tertiary amine (Alamine 336) was used as an extractant for lactic acid. The extraction capacity of Alamine 336 is greatly enhanced by addition of alcohol. Long-chain alcohols serve well for this purpose since they are less toxic to micro-organism. Addition of kerosene, a diluent, was necessary to reduce the solvent viscosity. A solvent mixture of 20%more » Alamine 336,40% oleyl alcohol, and 40% kerosene was found to be most effective in the extraction of lactic acid. Progressive change of pH from an initial value of 5.0 down to 4.3 has significantly improved the overall performance of the simultaneous saccharification and extractive fermentation over that of constant pH operation. The change of pH was applied to promote cell growth in the early phase, and extraction in the latter phase. 20 refs., 10 figs., 1 tab.« less
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Characterization of Lignocellulosic-Poly(lactic acid) reinforced composites
Q.X. Hou; X.S. Chai; R. Yang; T. Elder; A.J. Ragauskas
2005-01-01
The effects of adding poly(lactic acid) (PLA) to the physical strength of paper test sheets prepared from three unbleached loblolly pine kraft pulps with different amounts of lignin and an aspen bleached chemothermomechanical pulp were studied. The physical strength studies demonstrated that relatively low levels of PLA addition (0.5-4.0%) could dramatically improve...
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USDA-ARS?s Scientific Manuscript database
The controlled-release of natural plant oils such as linalool is of interest in therapeutics, cosmetics, and antimicrobial and larvicidal products. The present study reports the release characteristics of linalool encapsulated at three concentrations (10, 15 and 20 wt.%) in poly(lactic acid) nanofib...
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Yoshida, Shogo; Okano, Kenji; Tanaka, Tsutomu; Ogino, Chiaki; Kondo, Akihiko
2011-10-01
In order to achieve efficient D-lactic acid fermentation from a mixture of xylose and glucose, the xylose-assimilating xylAB operon from Lactobacillus pentosus (PXylAB) was introduced into an L-lactate dehydrogenase gene (ldhL1)-deficient Lactobacillus plantarum (ΔldhL1-xpk1::tkt-Δxpk2) strain in which the phosphoketolase 1 gene (xpk1) was replaced with the transketolase gene (tkt) from Lactococcus lactis, and the phosphoketolase 2 (xpk2) gene was deleted. Two copies of xylAB introduced into the genome significantly improved the xylose fermentation ability, raising it to the same level as that of ΔldhL1-xpk1::tkt-Δxpk2 harboring a xylAB operon-expressing plasmid. Using the two-copy xylAB integrated strain, successful homo-D-lactic acid production was achieved from a mixture of 25 g/l xylose and 75 g/l glucose without carbon catabolite repression. After 36-h cultivation, 74.2 g/l of lactic acid was produced with a high yield (0.78 g per gram of consumed sugar) and an optical purity of D-lactic acid of 99.5%. Finally, we successfully demonstrated homo-D-lactic acid fermentation from a mixture of three kinds of sugar: glucose, xylose, and arabinose. This is the first report that describes homo-D-lactic acid fermentation from mixed sugars without carbon catabolite repression using the xylose-assimilating pathway integrated into lactic acid bacteria.
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L: (+)-Lactic acid production from non-food carbohydrates by thermotolerant Bacillus coagulans.
Ou, Mark S; Ingram, Lonnie O; Shanmugam, K T
2011-05-01
Lactic acid is used as an additive in foods, pharmaceuticals, and cosmetics, and is also an industrial chemical. Optically pure lactic acid is increasingly used as a renewable bio-based product to replace petroleum-based plastics. However, current production of lactic acid depends on carbohydrate feedstocks that have alternate uses as foods. The use of non-food feedstocks by current commercial biocatalysts is limited by inefficient pathways for pentose utilization. B. coagulans strain 36D1 is a thermotolerant bacterium that can grow and efficiently ferment pentoses using the pentose-phosphate pathway and all other sugar constituents of lignocellulosic biomass at 50°C and pH 5.0, conditions that also favor simultaneous enzymatic saccharification and fermentation (SSF) of cellulose. Using this bacterial biocatalyst, high levels (150-180 g l(-1)) of lactic acid were produced from xylose and glucose with minimal by-products in mineral salts medium. In a fed-batch SSF of crystalline cellulose with fungal enzymes and B. coagulans, lactic acid titer was 80 g l(-1) and the yield was close to 80%. These results demonstrate that B. coagulans can effectively ferment non-food carbohydrates from lignocellulose to L: (+)-lactic acid at sufficient concentrations for commercial application. The high temperature fermentation of pentoses and hexoses to lactic acid by B. coagulans has these additional advantages: reduction in cellulase loading in SSF of cellulose with a decrease in enzyme cost in the process and a reduction in contamination of large-scale fermentations.
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Probiotic potential of noni juice fermented with lactic acid bacteria and bifidobacteria.
Wang, Chung-Yi; Ng, Chang-Chai; Su, Hsuan; Tzeng, Wen-Sheng; Shyu, Yuan-Tay
2009-01-01
The present study assesses the feasibility of noni as a raw substrate for the production of probiotic noni juice by lactic acid bacteria (Lactobacilluscasei and Lactobacillus plantarum) and bifidobacteria (Bifidobacteriumlongum). Changes in pH, acidity, sugar content, cell survival and antioxidant properties during fermentation were monitored. All tested strains grew well on noni juice, reaching nearly 10⁹ colony-forming units/ml after 48 h fermentation. L.casei produced less lactic acid than B.longum and L. plantarum. After 4 weeks of cold storage at 4°C, B.longum and L. plantarum survived under low-pH conditions in fermented noni juice. In contrast, L.casei exhibited no cell viability after 3 weeks. Moreover, noni juice fermented with B.longum had a high antioxidant capacity that did not differ significantly (P <0.05) from that of lactic acid bacteria. Finally, we found that B.longum and L. plantarum are optimal probiotics for fermentation with noni juice.
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Zan, Yifan; Sun, Yuanyuan; Kong, Lingzhao; Miao, Gai; Bao, Liwei; Wang, Hao; Li, Shenggang; Sun, Yuhan
2018-06-12
Formic acid induced controlled-release hydrolysis of sugar-rich microalgae (Scenedesmus) over the Sn-Beta catalyst was found to be a highly efficient process for producing lactic acid as a platform chemical. One-pot reaction with a very high lactic acid yield of 83.0% was realized in a batch reactor using water as the solvent. Under the attack of formic acid, the cell wall of Scenedesmus was disintegrated, and hydrolysis of the starch inside the cell was strengthened in a controlled-release mode, resulting in a stable and relatively low glucose concentration. Subsequently, the Sn-Beta catalyst was employed for the efficient conversion of glucose into lactic acid with stable catalytic performance through isomerization, retro-aldol and de-/rehydration reactions. Thus, the hydrolysis of polysaccharides and the catalytic conversion of the monosaccharide into lactic acid was realized by the synergy between an organic Brønsted acid and a heterogeneous Lewis acid catalyst. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Sun, Liang; Lu, Zhilong; Li, Jianxiu; Sun, Feifei; Huang, Ribo
2018-02-01
Mechanisms for high L-lactic acid production remain unclear in many bacteria. Lactobacillus rhamnosus SCT-10-10-60 was previously obtained from L. rhamnosus ATCC 11443 via mutagenesis and showed improved L-lactic acid production. In this study, the genomes of strains SCT-10-10-60 and ATCC 11443 were sequenced. Both genomes are a circular chromosome, 2.99 Mb in length with a GC content of approximately 46.8%. Eight split genes were identified in strain SCT-10-10-60, including two LytR family transcriptional regulators, two Rex redox-sensing transcriptional repressors, and four ABC transporters. In total, 60 significantly up-regulated genes (log 2 fold-change ≥ 2) and 39 significantly down-regulated genes (log 2 fold-change ≤ - 2) were identified by a transcriptome comparison between strains SCT-10-10-60 and ATCC 11443. KEGG pathway enrichment analysis revealed that "pyruvate metabolism" was significantly different (P < 0.05) between the two strains. The split genes and the differentially expressed genes involved in the "pyruvate metabolism" pathway are probably responsible for the increased L-lactic acid production by SCT-10-10-60. The genome and transcriptome sequencing information and comparison of SCT-10-10-60 with ATCC 11443 provide insights into the anabolism of L-lactic acid and a reference for improving L-lactic acid production using genetic engineering.
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Duarte, Ana Rita C; Maniglio, Devid; Sousa, Nuno; Mano, João F; Reis, Rui L; Migliaresi, Claudio
2017-01-26
This study investigated the preparation of ordered patterned surfaces and/or microspheres from a natural-based polymer, using the breath figure and reverse breath figure methods. Poly(D,L-lactic acid) and starch poly(lactic acid) solutions were precipitated in different conditions - namely, polymer concentration, vapor atmosphere temperature and substrate - to evaluate the effect of these conditions on the morphology of the precipitates obtained. The possibility of fine-tuning the properties of the final patterns simply by changing the vapor atmosphere was also demonstrated here using a range of compositions of the vapor phase. Porous films or discrete particles are formed when the differences in surface tension determine the ability of polymer solution to surround water droplets or methanol to surround polymer droplets, respectively. In vitro cytotoxicity was assessed applying a simple standard protocol to evaluate the possibility to use these materials in biomedical applications. Moreover, fluorescent microscopy images showed a good interaction of cells with the material, which were able to adhere on the patterned surfaces after 24 hours in culture. The development of patterned surfaces using the breath figure method was tested in this work for the preparation of both poly(lactic acid) and a blend containing starch and poly(lactic acid). The potential of these films to be used in the biomedical area was confirmed by a preliminary cytotoxicity test and by morphological observation of cell adhesion.
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Effects of lactic acid on astrocytes in primary culture.
Norenberg, M D; Mozes, L W; Gregorios, J B; Norenberg, L O
1987-03-01
Excessive tissue lactic acidosis is considered to be detrimental to the central nervous system (CNS) and may adversely affect recovery from anoxia, ischemia, trauma and epilepsy. Since astrocytes are believed to play a role in pH regulation in the CNS, we studied the effect of this acid on primary astrocyte cultures. Cells exposed to lactic acid showed chromatin clumping, an increase of lipid and dense bodies, a loss of polyribosomal clusters, slightly increased cytoplasmic lucency, swollen mitochondria and tangled intermediate filaments. These alterations progressed with lower pH and longer exposure. Irreversible changes occurred one to two hours after exposure at pH 6; after 30 to 60 minutes (min) at pH 5.5 and after ten to 30 min at pH 5. Comparable results were obtained with the use of other weak acids indicating that the observed changes were due to increased hydrogen ion concentration rather than secondary to lactate per se. Additionally, various concentrations of lactic acid adjusted to identical pH produced similar morphologic alterations. Thus, while lactic acid caused marked and at times irreversible alterations in astrocytes, severe and prolonged acidosis was required to produce such injurious effects. This relative resistance of astrocytes to acidosis is in keeping with their potential role in pH regulation in brain.
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GAS PERMEATION PROPERTIES OF POLY(LACTIC ACID). (R826733)
Abstract
The need for the development of polymeric materials based on renewable resources has led to the development of poly(lactic acid) (PLA) which is being produced from a feedstock of corn rather than petroleum. The present study examines the permeation of nitrogen...
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Glucansucrases from lactic acid bacteria which produce water-insoluble polysaccharides from sucrose
USDA-ARS?s Scientific Manuscript database
Dextrans and related glucans produced from sucrose by lactic acid bacteria have been studied for many years and are used in numerous commercial applications and products. Most of these glucans are water-soluble, except for a few notable exceptions from cariogenic Streptococcus spp. and a very small ...
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Lu, Hongying; Zhao, Xiao; Wang, Yongze; Ding, Xiaoren; Wang, Jinhua; Garza, Erin; Manow, Ryan; Iverson, Andrew; Zhou, Shengde
2016-02-19
A thermal tolerant stereo-complex poly-lactic acid (SC-PLA) can be made by mixing Poly-D-lactic acid (PDLA) and poly-L-lactic acid (PLLA) at a defined ratio. This environmentally friendly biodegradable polymer could replace traditional recalcitrant petroleum-based plastics. To achieve this goal, however, it is imperative to produce optically pure lactic acid isomers using a cost-effective substrate such as cellulosic biomass. The roadblock of this process is that: 1) xylose derived from cellulosic biomass is un-fermentable by most lactic acid bacteria; 2) the glucose effect results in delayed and incomplete xylose fermentation. An alternative strain devoid of the glucose effect is needed to co-utilize both glucose and xylose for improved D-lactic acid production using a cellulosic biomass substrate. A previously engineered L-lactic acid Escherichia coli strain, WL204 (ΔfrdBC ΔldhA ΔackA ΔpflB ΔpdhR ::pflBp6-acEF-lpd ΔmgsA ΔadhE, ΔldhA::ldhL), was reengineered for production of D-lactic acid, by replacing the recombinant L-lactate dehydrogenase gene (ldhL) with a D-lactate dehydrogenase gene (ldhA). The glucose effect (catabolite repression) of the resulting strain, JH13, was eliminated by deletion of the ptsG gene which encodes for IIBC(glc) (a PTS enzyme for glucose transport). The derived strain, JH14, was metabolically evolved through serial transfers in screw-cap tubes containing glucose. The evolved strain, JH15, regained improved anaerobic cell growth using glucose. In fermentations using a mixture of glucose (50 g L(-1)) and xylose (50 g L(-1)), JH15 co-utilized both glucose and xylose, achieving an average sugar consumption rate of 1.04 g L(-1)h(-1), a D-lactic acid titer of 83 g L(-1), and a productivity of 0.86 g L(-1) h(-1). This result represents a 46 % improved sugar consumption rate, a 26 % increased D-lactic acid titer, and a 48 % enhanced productivity, compared to that achieved by JH13. These results demonstrated that JH15 has the potential for fermentative production of D-lactic acid using cellulosic biomass derived substrates, which contain a mixture of C6 and C5 sugars.
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Choi, Hwa-Young; Ryu, Hee-Kyoung; Park, Kyung-Min; Lee, Eun Gyo; Lee, Hongweon; Kim, Seon-Won; Choi, Eui-Sung
2012-06-01
Lactic acid fermentation of Jerusalem artichoke tuber was performed with strains of Lactobacillus paracasei without acidic or enzymatic inulin hydrolysis prior to fermentation. Some strains of L. paracasei, notably KCTC13090 and KCTC13169, could ferment hot-water extract of Jerusalem artichoke tuber more efficiently compared with other Lactobacillus spp. such as L. casei type strain KCTC3109. The L. paracasei strains could utilize almost completely the fructo-oligosaccharides present in Jerusalem artichoke. Inulin-fermenting L. paracasei strains produced c.a. six times more lactic acid compared with L. casei KCTC3109. Direct lactic fermentation of Jerusalem artichoke tuber extract at 111.6g/L of sugar content with a supplement of 5 g/L of yeast extract by L. paracasei KCTC13169 in a 5L jar fermentor produced 92.5 ce:hsp sp="0.25"/>g/L of lactic acid with 16.8 g/L fructose equivalent remained unutilized in 72 h. The conversion efficiency of inulin-type sugars to lactic acid was 98% of the theoretical yield. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Shi, Zhouming; Wei, Peilian; Zhu, Xiangcheng; Cai, Jin; Huang, Lei; Xu, Zhinan
2012-10-10
Hydrolysate of Jerusalem artichoke was applied for the production of l-lactic acid by immobilized Lactococcus lactis cells in a fibrous bed bioreactor system. Preliminary experiments had indicated that the high quality hydrolysate, which was derived from the 40 min acid treatment at 95 °C and pH 1.8, was sufficient to support the cell growth and synthesis of l-lactic acid. With the addition of 5 g/l yeast extract, the fermentative performance of free cell system was evidently improved. After the basal settlement of hydrolysate based fermentation, the batch mode and the fed-batch mode fermentation were carried out in the free cell system and the fibrous bed bioreactor system, respectively. In all cases the immobilized cells presented the superior ability to produce l-lactic acid. The comparison of batch mode and fed-batch mode also indicated that the growth-limiting feeding strategy could reduce the lag phase of fermentation process and enhance the production of l-lactic acid. The achieved maximum concentration of l-lactic acid was 142 g/l in the fed-batch mode. Subsequent repeated-batch fermentation of the fibrous bed bioreactor system had further exhibited the persistence and stability of this system for the high production of l-lactic acid in a long term. Our work suggested the great potential of the fibrous bed bioreactor system and hydrolysate of J. artichoke in the economical production of l-lactic acid at industrial scale. Copyright © 2012 Elsevier Inc. All rights reserved.
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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.
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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
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NASA Astrophysics Data System (ADS)
Yang, Yingge; Fan, Yonghong; Li, Wen; Wang, Dongmei; Wu, Yuejin; Zheng, Zhiming; Yu, Zengliang
2007-10-01
In order to obtain an industrial strain with a higher L(+)-lactic acid yield, the strain Rhizopus oryzae PW352 was mutated by means of nitrogen ion beam implantation and the mutant strain Rhizopus oryzae RLC41-6 was obtained. An experimental finding was made in surprise that Rhizopus oryzae mutant RLC41-6 is not only an L(+)-lactic acid producer from corn starch but also an efficient producer of L(+)-lactic acid from xylose. Under optimal conditions, the production of L(+)-lactic acid from 100 g/L xylose reached 77.39 g/L after 144 h fed-batch fermentation. A high mutation rate and a wide mutation spectrum of low-energy ion implantation were observed in the experiment.
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Xiang, Yiming; Li, Jun; Liu, Xiangmei; Cui, Zhenduo; Yang, Xianjin; Yeung, K W K; Pan, Haobo; Wu, Shuilin
2017-10-01
Poly(lactic-co-glycolic acid)/Ag/ZnO nanorods coating were successfully prepared on the surface of Ti metallic implants using a hydrothermal method and subsequent spin-coating of mixtures of poly(lactic-co-glycolic acid) and silver nanoparticles. The poly(lactic-co-glycolic acid)/Ag/ZnO nanorods coating exhibited excellent antibacterial efficacy of over 96% against both Staphylococcus aureus and Escherichia coli when the initial content of Ag nanoparticles was over 3wt%. In addition, the release of both silver and zinc could last for over a hundred days due to the enwrapping of poly(lactic-co-glycolic acid). Proliferation of mouse calvarial cells exhibited minimal cytotoxicity on the poly(lactic-co-glycolic acid)/Ag/ZnO coating with an initial content of Ag nanoparticles of 1wt% and 3wt%, while it inhibited cell proliferation once this value was increased to 6wt%. The results revealed that this poly(lactic-co-glycolic acid)/Ag/ZnO composite could provide a long-lasting antibacterial approach and good cytocompatibility, thus exhibiting considerable potential for biomedical application in orthopedic and dental implants with excellent self-antibacterial activity and good biocompatibility. Copyright © 2017 Elsevier B.V. All rights reserved.
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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®
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Laboratory evaluation of lactic acid on attraction of Culex spp. (Diptera: Culicidae).
Allan, Sandra A; Bernier, Ulrich R; Kline, Daniel L
2010-12-01
The role of lactic acid was evaluated for attraction of Culex nigripalpus, Culex quinquefasciatus, Culex tarsalis, and Aedes aegypti in the laboratory using a dual-port olfactometer. When lactic acid was combined with chicken odor, attraction was increased for Cx. quinquefasciatus compared to chicken odor alone but not for Cx. nigripalpus, Cx. tarsalis, and Ae. aegypti. Lactic acid combined with hand odor did not change attraction of Cx. tarsalis and Ae. aegypti but decreased attraction of Cx. nigripalpus and Cx. quinquefasciatus. The addition of lactic acid to CO(2) increased attraction of Ae. aegypti and Cx. quinquefasciatus but reduced attraction of Cx. nigripalpus and Cx. tarsalis. Use of commercial lactic acid baits with CO(2) resulted in a similar trend except for Cx. nigripalpus which showed no difference. A blend of lactic acid, acetone, and dimethyl disulfide was attractive to Ae. aegypti (63.4%) but elicited low responses by all Culex spp. (1.3-26.8%). Addition of the blend to CO(2) increased attraction of Ae. aegypti and Cx. quinquefasciatus but reduced attraction of Cx. nigripalpus and Cx. tarsalis. The mixture of compounds plus CO(2) was as attractive as a hand for Cx. quinquefasciatus, Cx. tarsalis, and Ae. aegypti. © 2010 The Society for Vector Ecology.
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Tormo, Hélène; Ali Haimoud Lekhal, Djamila; Roques, C
2015-10-01
Lactic acid bacteria, in particular Lactococcus lactis, play a decisive role in the cheese making process and more particularly in lactic cheeses which are primarily produced on goat dairy farms. The objective of this study was therefore to identify the main lactic acid bacteria found in raw goats' milk from three different regions in France and evaluate if certain farming practices have an effect on the distribution of species of lactic acid bacteria in the various milk samples. Identification at genus or species level was carried out using phenotypic tests and genotypic methods including repetitive element REP-PCR, species-specific PCR and 16S rRNA gene sequencing. The distribution of the main bacterial species in the milk samples varied depending on farms and their characteristics. Out of the 146 strains identified, L. lactis was the dominant species (60% of strains), followed by Enterococcus (38%) of which Enterococcus faecalis and Enterococcus faecium. Within the species L. lactis, L. lactis subsp lactis was detected more frequently than L. lactis subsp cremoris (74% vs. 26%). The predominance of L. lactis subsp cremoris was linked to geographical area studied. It appears that the animals' environment plays a role in the balance between the dominance of L. lactis and enterococci in raw goats' milk. The separation between the milking parlor and the goat shed (vs no separation) and only straw in the bedding (vs straw and hay) seems to promote L. lactis in the milk (vs enterococci). Copyright © 2015 Elsevier B.V. All rights reserved.
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Jiang, Ting; Qiao, Hui; Zheng, Zhaojuan; Chu, Qiulu; Li, Xin; Yong, Qiang; Ouyang, Jia
2016-01-01
An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP) mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH) of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH), condensed acid-catalyzed liquid hot water hydrolysate (CALH) and condensed acid-catalyzed sulfite hydrolysate (CASH) as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF), vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal) on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates.
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Jiang, Ting; Qiao, Hui; Zheng, Zhaojuan; Chu, Qiulu; Li, Xin; Yong, Qiang; Ouyang, Jia
2016-01-01
An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP) mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH) of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH), condensed acid-catalyzed liquid hot water hydrolysate (CALH) and condensed acid-catalyzed sulfite hydrolysate (CASH) as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF), vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal) on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates. PMID:26863012
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Vaginal pH and microbicidal lactic acid when lactobacilli dominate the microbiota.
O'Hanlon, Deirdre E; Moench, Thomas R; Cone, Richard A
2013-01-01
Lactic acid at sufficiently acidic pH is a potent microbicide, and lactic acid produced by vaginal lactobacilli may help protect against reproductive tract infections. However, previous observations likely underestimated healthy vaginal acidity and total lactate concentration since they failed to exclude women without a lactobacillus-dominated vaginal microbiota, and also did not account for the high carbon dioxide, low oxygen environment of the vagina. Fifty-six women with low (0-3) Nugent scores (indicating a lactobacillus-dominated vaginal microbiota) and no symptoms of reproductive tract disease or infection, provided a total of 64 cervicovaginal fluid samples using a collection method that avoided the need for sample dilution and rigorously minimized aerobic exposure. The pH of samples was measured by microelectrode immediately after collection and under a physiological vaginal concentration of CO2. Commercial enzymatic assays of total lactate and total acetate concentrations were validated for use in CVF, and compared to the more usual HPLC method. The average pH of the CVF samples was 3.5 ± 0.3 (mean ± SD), range 2.8-4.2, and the average total lactate was 1.0% ± 0.2% w/v; this is a five-fold higher average hydrogen ion concentration (lower pH) and a fivefold higher total lactate concentration than in the prior literature. The microbicidal form of lactic acid (protonated lactic acid) was therefore eleven-fold more concentrated, and a markedly more potent microbicide, than indicated by prior research. This suggests that when lactobacilli dominate the vaginal microbiota, women have significantly more lactic acid-mediated protection against infections than currently believed. Our results invite further evaluations of the prophylactic and therapeutic actions of vaginal lactic acid, whether provided in situ by endogenous lactobacilli, by probiotic lactobacilli, or by products that reinforce vaginal lactic acid.
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Li, Ling; Eom, Hyun-Ju; Park, Jung-Mi; Seo, Eunyoung; Ahn, Ji Eun; Kim, Tae-Jip; Kim, Jeong Hwan; Han, Nam Soo
2012-10-10
Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293 is a lactic acid bacterium that converts pyruvate mainly to d-(-)-lactic acid by using d-(-)-lactate dehydrogenase (ldhD). The aim of this study was to identify the gene responsible for d-lactic acid formation in this organism and to characterize the enzyme to facilitate the production of optically pure d-lactic acid. A genomic analysis of L. mesenteroides ATCC 8293 revealed that 7 genes encode lactate-related dehydrogenase. According to transcriptomic, proteomic, and phylogenetic analyses, LEUM_1756 was the major gene responsible for the production of d-lactic acid. The LEUM_1756 gene, of 996bp and encoding 332 amino acids (36.5kDa), was cloned and overexpressed in Escherichia coli BL21(DE3) Star from an inducible pET-21a(+) vector. The enzyme was purified by Ni-NTA column chromatography and showed a specific activity of 4450U/mg, significantly higher than those of other previously reported ldhDs. The gel permeation chromatography analysis showed that the purified enzyme exists as tetramers in solution and this was the first report among lactic acid bacteria. The pH and temperature optima were pH 8.0 and 30°C, respectively, for the pyruvate reduction reaction, and pH 11.0 and 20°C, respectively, for the lactate oxidation reaction. The K(m) kinetic parameters for pyruvate and lactate were 0.58mM and 260mM, respectively. In addition, the k(cat) values for pyruvate and lactate were 2900s(-1) and 2280s(-1), respectively. The enzyme was not inhibited by Ca(2+), Co(2+), Cu(2+), Mg(2+), Mn(2+), Na(+), or urea, but was inhibited by 1mM Zn(2+) and 1mM SDS. Copyright © 2012 Elsevier Inc. All rights reserved.
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NASA Astrophysics Data System (ADS)
Sumardiono, Siswo; Pudjihastuti, Isti; Jos, Bakti; Taufani, Muhammad; Yahya, Faad
2017-05-01
Modified cassava starch is very prospective products in the food industry. The main consideration of this study is the increasing volume of imported wheat and the demand for modified cassava starch industry. The purpose of this study is the assessing of lactic acid hydrolysis and microwave heating impact to the physicochemical and rheological properties of modified cassava starch, and test applications of modified cassava starch to coated peanut expansion quality. Experimental variables include the concentration of lactic acid (0.5% w/w, 1% w/w; 2% w/w), a time of hydrolysis (15, 30, 45 minutes), a time of microwave heating (1, 2, 3 hours). The research step is by dissolving lactic acid using aquadest in the stirred tank reactor, then added cassava starch. Hydrolysed cassava starch was then heated by microwave. Physicochemical properties and rheology of the modified cassava starch is determined by the solubility, swelling power, and test congestion. The optimum obtained results indicate that solubility, swelling power, congestion test, respectively for 19.75%; 24.25% and 826.10% in the hydrolysis treatment for 15 minutes, 1% w lactic acid and microwave heating 3 hours. The physicochemical and rheological properties of modified cassava starch have changed significantly when compared to the native cassava starch. Furthermore, these modified cassava starch are expected to be used for the substitution of food products.
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Campanella, Daniela; Rizzello, Carlo Giuseppe; Fasciano, Cristina; Gambacorta, Giuseppe; Pinto, Daniela; Marzani, Barbara; Scarano, Nicola; De Angelis, Maria; Gobbetti, Marco
2017-08-01
This study aimed at using grape marc for the growth of lactic acid bacteria and bifidobacteria with the perspective of producing a functional ingredient having antioxidant activity. Lactobacillus plantarum 12A and PU1, Lactobacillus paracasei 14A, and Bifidobacterium breve 15A showed the ability to grow on grape marc (GM) based media. The highest bacterial cell density (>9.0 CFU/g) was found in GM added of 1% of glucose (GMG). Compared to un-inoculated and incubated control fermented GMG showed a decrease of carbohydrates and citric acid together with an increase of lactic acid. The content of several free amino acids and phenol compounds differed between samples. Based on the survival under simulated gastro-intestinal conditions, GMG was a suitable carrier of lactic acid bacteria and bifidobacteria strains. Compared to the control, cell-free supernatant (CFS) of fermented GMG exhibited a marked antioxidant activity in vitro. The increased antioxidant activity was confirmed using Caco-2 cell line after inducing oxidative stress, and determining cell viability and radical scavenging activity through MTT and DCFH-DA assays, respectively. Supporting these founding, the SOD-2 gene expression of Caco-2 cells also showed a lowest pro-oxidant effect induced by the four CFS of GMG fermented by lactic acid bacteria and bifidobacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Catalytic processing of lactic acid over Pt/Nb(2)O(5).
Serrano-Ruiz, Juan Carlos; Dumesic, James A
2009-01-01
Dilute aqueous solutions of lactic acid (30 %wt.) can be catalytically processed at 573 K and 57 bar over a low-metal-content Pt(0.1 %)/Nb(2)O(5) catalyst in a spontaneously separating organic phase rich in valuable products such as C(4)-C(7) ketones. An increase in the lactic acid concentration to 60 wt % allows conversion of approximately 50 % of the carbon feed in this organic layer, while maintaining good stability of the catalyst. Experiments at low conversion showed that lactic acid reacts first over Pt(0.1 %)/Nb(2)O(5) to produce acetaldehyde and propanoic acid (along with CO and CO(2) in the gas phase). These compounds (less oxygenated than lactic acid but still reactive) are the key intermediates in the overall process, and they react differently depending on the nature of the catalyst support. In particular, reaction kinetics studies with propanoic acid as feed showed that Pt(0.1 %)/Nb(2)O(5) favored the formation of pentanones by ketonization reactions, whereas a monofunctional Pt(0.1 %)/carbon catalyst produced ethane and CO(x) by decomposition reactions. In the same manner, acetaldehyde was preferentially hydrogenated to ethanol over Pt(0.1 %)/carbon, whereas the presence of niobia allowed this intermediate to react (by successive aldol condensations) to form C(4)-C(7) condensation products stored in the organic phase. Finally, reaction pathways are proposed to explain the catalytic processing of lactic acid over bifunctional Pt(0.1 %)/Nb(2)O(5). In this scheme, metal sites catalyze hydrogenation reactions and niobia promotes C--C coupling processes (ketonization and aldol condensation), in contrast to C--C cleavage reactions which take place preferentially over Pt(0.1 %)/carbon and lead to loss of carbon in the gas effluent as CO, CO(2), and methane.
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A Glutamic Acid-Producing Lactic Acid Bacteria Isolated from Malaysian Fermented Foods
Zareian, Mohsen; Ebrahimpour, Afshin; Bakar, Fatimah Abu; Mohamed, Abdul Karim Sabo; Forghani, Bita; Ab-Kadir, Mohd Safuan B.; Saari, Nazamid
2012-01-01
l-glutamaic acid is the principal excitatory neurotransmitter in the brain and an important intermediate in metabolism. In the present study, lactic acid bacteria (218) were isolated from six different fermented foods as potent sources of glutamic acid producers. The presumptive bacteria were tested for their ability to synthesize glutamic acid. Out of the 35 strains showing this capability, strain MNZ was determined as the highest glutamic-acid producer. Identification tests including 16S rRNA gene sequencing and sugar assimilation ability identified the strain MNZ as Lactobacillus plantarum. The characteristics of this microorganism related to its glutamic acid-producing ability, growth rate, glucose consumption and pH profile were studied. Results revealed that glutamic acid was formed inside the cell and excreted into the extracellular medium. Glutamic acid production was found to be growth-associated and glucose significantly enhanced glutamic acid production (1.032 mmol/L) compared to other carbon sources. A concentration of 0.7% ammonium nitrate as a nitrogen source effectively enhanced glutamic acid production. To the best of our knowledge this is the first report of glutamic acid production by lactic acid bacteria. The results of this study can be further applied for developing functional foods enriched in glutamic acid and subsequently γ-amino butyric acid (GABA) as a bioactive compound. PMID:22754309
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Vargas, E; Ruiz, M A; Campuzano, S; González de Rivera, G; López-Colino, F; Reviejo, A J; Pingarrón, J M
2016-05-15
An integrated amperometric d-lactic acid biosensor involving a gold film deposited by sputtering on a stainless steel disk electrode where the enzymes D-lactic acid dehydrogenase (DLDH) and diaphorase (DP) as well as the redox mediator tetrathiafulvalene (TTF) are coimmobilized by using a dialysis membrane, is reported in this work. Amperometry in stirred solutions at a detection potential of +0.15 V (vs Ag/AgCl reference electrode) provided a linear calibration plot for D-lactic acid over the 1.0×10(-4) to 3.8×10(-3) g L(-1) concentration range, with a limit of detection of 3.1×10(-5) g L(-1). The usefulness of the biosensor was demonstrated by determining D-lactic acid in beer samples with good results. Additionally, the biosensor was implemented together with a commercial L-lactic amperometric biosensor in a semiautomatic flow-injection analysis (FIA) system able to perform a rapid and simple stereo-specific determination of D- and D-lactic without a previous separation step. The operational characteristics of the biosensors under flow conditions were evaluated and its applicability was demonstrated through the simultaneous determination of both enantiomers in beer samples. Copyright © 2016 Elsevier B.V. All rights reserved.
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21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.
Code of Federal Regulations, 2014 CFR
2014-04-01
... § 172.852 Glyceryl-lacto esters of fatty acids. Glyceryl-lacto esters of fatty acids (the lactic acid... conditions: (a) They are manufactured from glycerin, lactic acid, and fatty acids conforming with § 172.860...
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... liver or kidney Blood sugar test Genetic testing Lactic acid blood test Triglyceride level Uric acid blood ... sugar and high levels of lactate (produced from lactic acid), blood fats (lipids), and uric acid.
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Moens, Frédéric; Lefeber, Timothy; De Vuyst, Luc
2014-03-01
Four cocoa-specific acetic acid bacterium (AAB) strains, namely, Acetobacter pasteurianus 386B, Acetobacter ghanensis LMG 23848(T), Acetobacter fabarum LMG 24244(T), and Acetobacter senegalensis 108B, were analyzed kinetically and metabolically during monoculture laboratory fermentations. A cocoa pulp simulation medium (CPSM) for AAB, containing ethanol, lactic acid, and mannitol, was used. All AAB strains differed in their ethanol and lactic acid oxidation kinetics, whereby only A. pasteurianus 386B performed a fast oxidation of ethanol and lactic acid into acetic acid and acetoin, respectively. Only A. pasteurianus 386B and A. ghanensis LMG 23848(T) oxidized mannitol into fructose. Coculture fermentations with A. pasteurianus 386B or A. ghanensis LMG 23848(T) and Lactobacillus fermentum 222 in CPSM for lactic acid bacteria (LAB) containing glucose, fructose, and citric acid revealed oxidation of lactic acid produced by the LAB strain into acetic acid and acetoin that was faster in the case of A. pasteurianus 386B. A triculture fermentation with Saccharomyces cerevisiae H5S5K23, L. fermentum 222, and A. pasteurianus 386B, using CPSM for LAB, showed oxidation of ethanol and lactic acid produced by the yeast and LAB strain, respectively, into acetic acid and acetoin. Hence, acetic acid and acetoin are the major end metabolites of cocoa bean fermentation. All data highlight that A. pasteurianus 386B displayed beneficial functional roles to be used as a starter culture, namely, a fast oxidation of ethanol and lactic acid, and that these metabolites play a key role as substrates for A. pasteurianus in its indispensable cross-feeding interactions with yeast and LAB during cocoa bean fermentation.
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Moens, Frédéric; Lefeber, Timothy
2014-01-01
Four cocoa-specific acetic acid bacterium (AAB) strains, namely, Acetobacter pasteurianus 386B, Acetobacter ghanensis LMG 23848T, Acetobacter fabarum LMG 24244T, and Acetobacter senegalensis 108B, were analyzed kinetically and metabolically during monoculture laboratory fermentations. A cocoa pulp simulation medium (CPSM) for AAB, containing ethanol, lactic acid, and mannitol, was used. All AAB strains differed in their ethanol and lactic acid oxidation kinetics, whereby only A. pasteurianus 386B performed a fast oxidation of ethanol and lactic acid into acetic acid and acetoin, respectively. Only A. pasteurianus 386B and A. ghanensis LMG 23848T oxidized mannitol into fructose. Coculture fermentations with A. pasteurianus 386B or A. ghanensis LMG 23848T and Lactobacillus fermentum 222 in CPSM for lactic acid bacteria (LAB) containing glucose, fructose, and citric acid revealed oxidation of lactic acid produced by the LAB strain into acetic acid and acetoin that was faster in the case of A. pasteurianus 386B. A triculture fermentation with Saccharomyces cerevisiae H5S5K23, L. fermentum 222, and A. pasteurianus 386B, using CPSM for LAB, showed oxidation of ethanol and lactic acid produced by the yeast and LAB strain, respectively, into acetic acid and acetoin. Hence, acetic acid and acetoin are the major end metabolites of cocoa bean fermentation. All data highlight that A. pasteurianus 386B displayed beneficial functional roles to be used as a starter culture, namely, a fast oxidation of ethanol and lactic acid, and that these metabolites play a key role as substrates for A. pasteurianus in its indispensable cross-feeding interactions with yeast and LAB during cocoa bean fermentation. PMID:24413595
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Nanocomposites from lignin-containing cellulose nanocrystals and poly(lactic acid)
Liqing Wei; Umesh Agarwal; Nicole Stark; Ronald Sabo
2017-01-01
Utilizing lignin-containing cellulose nanocrystals (HLCNCs) as reinforcing agents to poly(lactic acid) (PLA) for nanocomposites was studied for the first time. The PLA/HLCNCs nanocomposites were prepared by extrusion and injecting molding. The freeze-dried HLCNCs showed micron scale agglomerates. As indicated by the water contact angle measurements, the HLCNCs were...
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Dietary influence of kefir on microbial activities in the mouse bowel.
Marquina, Domingo; Santos, A; Corpas, I; Muñoz, J; Zazo, J; Peinado, J M
2002-01-01
In this work the microflora present in kefir, a fermented milk product, was studied together with the effect of kefir administration on different groups of indigenous bacteria of mouse bowel. Kefir microflora was composed of lactic acid bacteria, acetic acid bacteria and yeasts. Yeast population was composed of Saccharomyces cerevisiae, S. unisporus, Candida kefir, Kluyveromyces marxianus and K. lactis. The streptococci levels in kefir treated mice increased by 10-fold and the levels of sulfite-reducing clostridia decreased by 100-fold. The number of lactic acid bacteria increased significantly. The administration of kefir significantly increased the lactic acid bacteria counts in the mucosa of the bowel. Ingestion of kefir specifically lowered microbial populations of Enterobacteriaceae and clostridia. This is the first long-term study about the effects of the kefir administration on the intestinal microflora of mice.
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Production of Bakers' Yeast in Cheese Whey Ultrafiltrate †
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
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Functional genomics of lactic acid bacteria: from food to health
2014-01-01
Genome analysis using next generation sequencing technologies has revolutionized the characterization of lactic acid bacteria and complete genomes of all major groups are now available. Comparative genomics has provided new insights into the natural and laboratory evolution of lactic acid bacteria and their environmental interactions. Moreover, functional genomics approaches have been used to understand the response of lactic acid bacteria to their environment. The results have been instrumental in understanding the adaptation of lactic acid bacteria in artisanal and industrial food fermentations as well as their interactions with the human host. Collectively, this has led to a detailed analysis of genes involved in colonization, persistence, interaction and signaling towards to the human host and its health. Finally, massive parallel genome re-sequencing has provided new opportunities in applied genomics, specifically in the characterization of novel non-GMO strains that have potential to be used in the food industry. Here, we provide an overview of the state of the art of these functional genomics approaches and their impact in understanding, applying and designing lactic acid bacteria for food and health. PMID:25186768
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Functional genomics of lactic acid bacteria: from food to health.
Douillard, François P; de Vos, Willem M
2014-08-29
Genome analysis using next generation sequencing technologies has revolutionized the characterization of lactic acid bacteria and complete genomes of all major groups are now available. Comparative genomics has provided new insights into the natural and laboratory evolution of lactic acid bacteria and their environmental interactions. Moreover, functional genomics approaches have been used to understand the response of lactic acid bacteria to their environment. The results have been instrumental in understanding the adaptation of lactic acid bacteria in artisanal and industrial food fermentations as well as their interactions with the human host. Collectively, this has led to a detailed analysis of genes involved in colonization, persistence, interaction and signaling towards to the human host and its health. Finally, massive parallel genome re-sequencing has provided new opportunities in applied genomics, specifically in the characterization of novel non-GMO strains that have potential to be used in the food industry. Here, we provide an overview of the state of the art of these functional genomics approaches and their impact in understanding, applying and designing lactic acid bacteria for food and health.
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Zhang, Yixing; Vadlani, Praveen V
2015-06-01
Lignocellulosic biomass is an attractive alternative resource for producing chemicals and fuels. Xylose is the dominating sugar after hydrolysis of hemicellulose in the biomass, but most microorganisms either cannot ferment xylose or have a hierarchical sugar utilization pattern in which glucose is consumed first. To overcome this barrier, Lactobacillus brevis ATCC 367 was selected to produce lactic acid. This strain possesses a relaxed carbon catabolite repression mechanism that can use glucose and xylose simultaneously; however, lactic acid yield was only 0.52 g g(-1) from a mixture of glucose and xylose, and 5.1 g L(-1) of acetic acid and 8.3 g L(-1) of ethanol were also formed during production of lactic acid. The yield was significantly increased and ethanol production was significantly reduced if L. brevis was co-cultivated with Lactobacillus plantarum ATCC 21028. L. plantarum outcompeted L. brevis in glucose consumption, meaning that L. brevis was focused on converting xylose to lactic acid and the by-product, ethanol, was reduced due to less NADH generated in the fermentation system. Sequential co-fermentation of L. brevis and L. plantarum increased lactic acid yield to 0.80 g g(-1) from poplar hydrolyzate and increased yield to 0.78 g lactic acid per g of biomass from alkali-treated corn stover with minimum by-product formation. Efficient utilization of both cellulose and hemicellulose components of the biomass will improve overall lactic acid production and enable an economical process to produce biodegradable plastics. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
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Lactic acid bacteria of meat and meat products.
Egan, A F
1983-09-01
When the growth of aerobic spoilage bacteria is inhibited, lactic acid bacteria may become the dominant component of the microbial flora of meats. This occurs with cured meats and with meats packaged in films of low gas permeability. The presence of a flora of psychrotrophic lactic acid bacteria on vacuum-packaged fresh chilled meats usually ensures that shelf-life is maximal. When these organisms spoil meats it is generally by causing souring, however other specific types of spoilage do occur. Some strains cause slime formation and greening of cured meats, and others may produce hydrogen sulphide during growth on vacuum-packaged beef. The safety and stability of fermented sausages depends upon fermentation caused by lactic acid bacteria. Overall the presence on meats of lactic acid bacteria is more desirable than that of the types of bacteria they have replaced.
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Microbial acid production (Clinpro Cario L-Pop) and dental caries in infants and children.
Bretz, W A; Corby, P M A; Costa, S; Quadros, M; Tavares, V S; Moreira, G; Filho, M R Melo; Weyant, R J
2007-04-01
The purpose of this study was to evaluate the diagnostic utility of the Clinpro Cario-L-Pop test as it relates to dental caries rates and severity in infants and children. The study population was comprised of 771 infants and children who were on average 5.2 years of age (range of 1.5 to 8 years of age). Examiners conducted dental caries clinical examination using established criteria. In addition, lesion severity was determined be measuring its depth. An indicator swab was applied to the tongue dorsum until completely moistened with saliva. The indicator swab was processed according to the manufacturer's instructions, and acid production was assessed with the aid of a color chart. Twenty-three percent of children were caries free, and 7% (n = 50) of participants were categorized as having low production of lactic acid (scores 1 to 3), 17% (n = 135) moderate production of lactic acid (scores 4 to 6), and 76% (n = 586) high production of lactic acid (scores 7 to 9). There was a tendency for moderate and high lactic acid formers to exhibit higher surface-based caries prevalence rates, higher rates for deep dentinal lesions, and increased lesion severity. There was a linear increase of white spot surface-based lesions from low to high lactic acid formers and for initial dentinal lesions. Clinpro Cario-L-Pop test results, when controlling for age and gender, significantly distinguished caries-free participants from those exhibiting any form of decay. These results suggest that Clinpro Cario-L-Pop test was useful in explaining elevated frequency and severity of dental caries in spite of the high levels of decay and of microbial acid production observed in this population.
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Chen, Lei; Guo, Gang; Yuan, Xianjun; Zhang, Jie; Li, Junfeng; Shao, Tao
2016-03-30
The objective of this study was to investigate the effect of molasses, lactic acid bacteria and propionic acid on the fermentation quality, aerobic stability and in vitro gas production of total mixed ration (TMR) silage prepared with oat-common vetch intercrop on the Tibetan plateau. TMR (436 g kg(-1) dry matter (DM)) was ensiled with six experimental treatments: (1) no additives (control); (2) molasses (M); (3) an inoculant (Lactobacillus plantarum) (L); (4) propionic acid (P); (5) molasses + propionic acid (MP); (6) inoculant + propionic acid (LP). All silages were well preserved with low pH (< 4.19) and NH3-N contents, and high lactic acid contents after ensiling for 45 days. L and PL silages underwent a more efficient fermentation than silages without L. P and MP silages inhibited lactic acid production. Under aerobic conditions, M and L silage reduced aerobic stability for 15 and 74 h, respectively. All silages that had propionic acid in their treatments markedly (P < 0.05) improved the aerobic stability. After 72 h incubation, all additives treatments increased (P < 0.05) the 72 h cumulative gas production and in vitro DM digestibility (IVDMD) as compared with the control. L treatment decreased (P < 0.05) in vitro neutral detergent fibre degradability. Our findings show that TMR prepared with oat-common vetch intercrop can be well preserved. Although propionic acid is compatible with lactic acid bacteria, and when used together, they had minor effects on fermentation, aerobic stability and in vitro digestibility of TMR silage prepared with oat-common vetch intercrop. © 2015 Society of Chemical Industry.
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Zheng, Lu; Liu, Mingqing; Sun, Jiaduo; Wu, Bin; He, Bingfang
2017-05-01
Sporolactobacillus inulinus is a superior D-lactic acid-producing bacterium and proposed species for industrial production. The major pathway for D-lactic acid biosynthesis, glycolysis, is mainly regulated via the two irreversible steps catalyzed by the allosteric enzymes, phosphofructokinase (PFK) and pyruvate kinase. The activity level of PFK was significantly consistent with the cell growth and D-lactic acid production, indicating its vital role in control and regulation of glycolysis. In this study, the ATP-dependent PFK from S. inulinus was expressed in Escherichia coli and purified to homogeneity. The PFK was allosterically activated by both GDP and ADP and inhibited by phosphoenolpyruvate; the addition of activators could partly relieve the inhibition by phosphoenolpyruvate. Furthermore, monovalent cations could enhance the activity, and Na + was the most efficient one. Considering this kind activation, NaOH was investigated as the neutralizer instead of the traditional neutralizer CaCO 3 . In the early growth stage, the significant accelerated glucose consumption was achieved in the NaOH case probably for the enhanced activity of Na + -activated PFK. Using NaOH as the neutralizer at pH 6.5, the fermentation time was greatly shortened about 22 h; simultaneously, the glucose consumption rate and the D-lactic acid productivity were increased by 34 and 17%, respectively. This probably contributed to the increased pH and Na + -promoted activity of PFK. Thus, fermentations by S. inulinus using the NaOH neutralizer provide a green and highly efficient D-lactic acid production with easy subsequent purification.
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Ghahremani, Enayat; Mardani, Mahnaz; Rezapour, Sadegh
2015-03-01
Lactic acid bacteria (LAB) with proteolitic activity are used as aromatic and antibacterial substances, cholesterol reduces, bile salt hydrolyses, and probiotic. The aims of this project were to isolate and identify natural LAB flora involved in traditional fermentation in cheeses of Khoramabad city and also to survey their probiotic potential. In order to achieve this goal, LAB were isolated and characterized using phenotypic and genotypic methods (PCR-sequencing); in the next stage, they were analyzed lowering cholesterol medium, hydrolysis of the bile, resistance to bile-resistant PH acidic stomach. At the end of the study, 88 cocci and 3 bacill were found: 58 Enterococcus faecium, 16 Enterococcus hirae, 5 Lactococcus lactis, 3 Lactobacillus plantarum, and 9 undetermined. The probiotic results of the bacteria had effects on the reduction of cholesterol, resistance to stomach acid, had relative antibacterial effects, and some strains had effects on hydrolyzing the bile. For further identification, the PCR method and the application of 16s-DNA-ITS genes and its sequencing were found useful. This study showed that lactic acid bacteria in the traditional cheese of the Khorramabad city have relative probiotic effect and that these lactic acid bacteria in fermented milk are suitable.
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Lactic acid peeling in superficial acne scarring in Indian skin.
Sachdeva, Silonie
2010-09-01
Chemical peeling with both alpha and beta hydroxy acids has been used to improve acne scarring with pigmentation. Lactic acid, a mild alpha hydroxy acid, has been used in the treatment of various dermatological indications but no study is reported in acne scarring with pigmentation. To evaluate the efficacy and safety of full strength pure lactic acid 92% (pH 2.0) chemical peel in superficial acne scarring in Indian skin. Seven patients, Fitzpatrick skin type IV-V, in age group 20-30 years with superficial acne scarring were enrolled in the study. Chemical peeling was done with lactic acid at an interval of 2 weeks to a maximum of four peels. Pre- and post-peel clinical photographs were taken at every session. Patients were followed every month for 3 months after the last peel to evaluate the effects. At the end of 3 months, there was definite improvement in the texture, pigmentation, and appearance of the treated skin, with lightening of scars. Significant improvement (greater than 75% clearance of lesions) occurred in one patient (14.28%), good improvement (51-75% clearance) in three patients (42.84%), moderate improvement (26-50% clearance) in two patients (28.57%), and mild improvement (1-25% clearance) in one patient (14.28%). © 2010 Wiley Periodicals, Inc.
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Huang, Yanna; You, Chunping; Liu, Zhenmin
2017-07-01
Lactobacillus delbrueckii subsp. bulgaricus is a heterogenous lactic acid bacterium that converts pyruvate mainly to D-lactic acid using D-lactate dehydrogenases (D-LDHs), whose functional properties remain poorly characterized. Here, the D-LDHs genes (ldb0101, ldb0813, ldb1010, ldb1147 and ldb2021) were cloned and overexpressed in Escherichia coli JM109 from an inducible pUC18 vector, respectively, and the resulting strains were compared in terms of D-lactic acid production. The strain expressing ldb0101 and ldb1010 gene individually produced more D-lactate than other three strains. Further study revealed that Ldb0101 activity was down-regulated by the oxygen and, therefore, achieved a highest titer of D-lactate (1.94 g/L) under anaerobic condition, and introduction of ldb1010 gene enhanced D-lactate formation (0.94 and 0.85 g/L, respectively) both in aerobic and anaerobic conditions due to a relatively stable q d-lactate . Our results suggested that the enzyme Ldb0101 and Ldb1010 played a role of more importance in D-lactate formation. To the best of our knowledge, we demonstrate for the first time the roles of different D-LDH homologs from L. bulgaricus in D-lactic acid production.
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Zhang, Danru; Zheng, Lu; Wu, Bin; He, Bingfang
2016-11-04
Sporolactobacillus inulinus, a typical homofermentative lactic acid bacterium, is an efficient D-lactic acid producer. Various environment factors affect the productivity of S. inulinus. Glucokinase, phosphofructokinase, pyruvate kinase and lactic dehydrogenase are the key enzymes of D-lactic acid production from glucose by S. inulinus. The characteristics of these enzymes are important in controlling and regulating the fermentation process. According to the genome bioinformatics analysis of S. inulinus CASD, three putative D-lactate dehydrogenases were identified, among which the bifunctional protein had been reported. In this study, we provided insights into the characteristics of the other two D-lactate dehydrogenase isozymes. S. inulinus Y2-8 genome was used as the template to amplify D-lactate dehydrogenase gene (dldh) and D-isomer specific 2-hydroxyacid dehydrogenase gene (dhdh). The two recombinant strains E-pET-28a/dldh and E-pET-28a/dhdh were constructed for enzyme expression. Both recombinants DLDH and DHDH could convert pyruvic acid into D-lactic acid. Enzymes expressed by recombinant strains were purified by Ni-NTA chromatography. The apparent molecular mass of DLDH was approximately 37 kDa by SDS-PAGE analysis, and DLDH showed a high affinity to pyruvate with the Km value of (0.58±0.04) mmol/L. The optimal reaction temperature and pH for DLDH was 35℃ and 6.5, respectively. The apparent molecular mass of DHDH was approximately 39 kDa, and the Km of DHDH toward pyruvate was (1.70±0.08) mmol/L. The optimum catalysis temperature and pH of DHDH were 30℃ and 7.5, respectively. According to the Km and optimal reaction pH, DLDH was suggested as the main catalyst in formation D-lactic acid from pyruvate during the fermentation. The enzymatic properties would contribute to the regulation of the fermentation of S. inulinus.
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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
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Exploitation of vegetables and fruits through lactic acid fermentation.
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.
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Increased d-lactic Acid intestinal bacteria in patients with chronic fatigue syndrome.
Sheedy, John R; Wettenhall, Richard E H; Scanlon, Denis; Gooley, Paul R; Lewis, Donald P; McGregor, Neil; Stapleton, David I; Butt, Henry L; DE Meirleir, Kenny L
2009-01-01
Patients with chronic fatigue syndrome (CFS) are affected by symptoms of cognitive dysfunction and neurological impairment, the cause of which has yet to be elucidated. However, these symptoms are strikingly similar to those of patients presented with D-lactic acidosis. A significant increase of Gram positive facultative anaerobic faecal microorganisms in 108 CFS patients as compared to 177 control subjects (p<0.01) is presented in this report. The viable count of D-lactic acid producing Enterococcus and Streptococcus spp. in the faecal samples from the CFS group (3.5 x 10(7) cfu/L and 9.8 x 10(7) cfu/L respectively) were significantly higher than those for the control group (5.0 x 10(6) cfu/L and 8.9 x 10(4) cfu/L respectively). Analysis of exometabolic profiles of Enterococcus faecalis and Streptococcus sanguinis, representatives of Enterococcus and Streptococcus spp. respectively, by NMR and HPLC showed that these organisms produced significantly more lactic acid (p<0.01) from (13)C-labeled glucose, than the Gram negative Escherichia coli. Further, both E. faecalis and S. sanguinis secrete more D-lactic acid than E. coli. This study suggests a probable link between intestinal colonization of Gram positive facultative anaerobic D-lactic acid bacteria and symptom expressions in a subgroup of patients with CFS. Given the fact that this might explain not only neurocognitive dysfunction in CFS patients but also mitochondrial dysfunction, these findings may have important clinical implications.
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Bering, Stine; Sjøltov, Laila; Wrisberg, Seema S; Berggren, Anna; Alenfall, Jan; Jensen, Mikael; Højgaard, Liselotte; Tetens, Inge; Bukhave, Klaus
2007-11-01
Lactic acid-fermented foods have been shown to increase Fe absorption in human subjects, possibly by lowering pH, activation of phytases, production of organic acids, or by the viable lactic acid bacteria. In this study the effect of a heat-inactivated lactic acid-fermented oat gruel with and without added viable, lyophilized Lactobacillus plantarum 299v on non-haem Fe absorption was investigated. Furthermore, Fe absorption in the distal intestine was determined. In a randomized, double-blinded crossover trial eighteen healthy young women aged 22 (SD 3) years with low Fe status (serum ferritin < 30 microg/l) were served the two test gruels, extrinsically labelled with 59Fe and served with two enterocoated capsules (containing 55Fe(II) and 55Fe(III), respectively) designed to disintegrate in the ileum. The meals were consumed on two consecutive days, e.g. in the order AA followed by BB in a second period. Non-haem Fe absorption was determined from 59Fe whole-body retention and isotope activities in blood samples. The concentrations of Fe, lactate, phytate, and polyphenols, and the pH were similar in the heat-inactivated lactic acid-fermented oat gruels with and without added L. plantarum 299v, and no difference in Fe absorption was observed between the test gruels (1.4 and 1.3%, respectively). Furthermore, no absorption of Fe in the distal intestine was observed. In conclusion, addition of viable, lyophilized lactobacillus to a heat-inactivated lactic acid-fermented oat gruel does not affect Fe absorption, and no absorption seems to occur in the distal part of the intestine from low Fe bioavailability meals in these women.
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A common bacterial metabolite elicits prion-based bypass of glucose repression
Garcia, David M; Dietrich, David; Clardy, Jon; Jarosz, Daniel F
2016-01-01
Robust preference for fermentative glucose metabolism has motivated domestication of the budding yeast Saccharomyces cerevisiae. This program can be circumvented by a protein-based genetic element, the [GAR+] prion, permitting simultaneous metabolism of glucose and other carbon sources. Diverse bacteria can elicit yeast cells to acquire [GAR+], although the molecular details of this interaction remain unknown. Here we identify the common bacterial metabolite lactic acid as a strong [GAR+] inducer. Transient exposure to lactic acid caused yeast cells to heritably circumvent glucose repression. This trait had the defining genetic properties of [GAR+], and did not require utilization of lactic acid as a carbon source. Lactic acid also induced [GAR+]-like epigenetic states in fungi that diverged from S. cerevisiae ~200 million years ago, and in which glucose repression evolved independently. To our knowledge, this is the first study to uncover a bacterial metabolite with the capacity to potently induce a prion. DOI: http://dx.doi.org/10.7554/eLife.17978.001 PMID:27906649
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Fundamentals of poly(lactic acid) microstructure, crystallization behavior, and properties
NASA Astrophysics Data System (ADS)
Kang, Shuhui
Poly(lactic acid) is an environmentally-benign biodegradable and sustainable thermoplastic material, which has found broad applications as food packaging films and as non-woven fibers. The crystallization and deformation mechanisms of the polymer are largely determined by the distribution of conformation and configuration. Knowledge of these mechanisms is needed to understand the mechanical and thermal properties on which processing conditions mainly depend. In conjunction with laser light scattering, Raman spectroscopy and normal coordinate analysis are used in this thesis to elucidate these properties. Vibrational spectroscopic theory, Flory's rotational isomeric state (RIS) theory, Gaussian chain statistics and statistical mechanics are used to relate experimental data to molecular chain structure. A refined RIS model is proposed, chain rigidity recalculated and chain statistics discussed. A Raman spectroscopic characterization method for crystalline and amorphous phase orientation has been developed. A shrinkage model is also proposed to interpret the dimensional stability for fibers and uni- or biaxially stretched films. A study of stereocomplexation formed by poly(l-lactic acid) and poly(d-lactic acid) is also presented.
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Miriam Unger; Julia Sedlmair; Heinz W. Siesler; Carol Hirschmugl; Barbara Illman
2014-01-01
In the present study, 3D FT-IR spectroscopic imaging measurements were applied to study the phase separation of a poly(3-hydroxybutyrate) (PHB)/poly(L-lactic acid) (PLA) (50:50 wt.%) polymer blend film. While in 2D projection imaging the z-dependent information is overlapped, thereby complicating the analysis, FT-IR spectro-micro-tomography,...
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D-lactic acidosis - case report and review of the literature.
Fabian, Elisabeth; Kramer, Ludwig; Siebert, Franz; Högenauer, Christoph; Raggam, Reinhard Bernd; Wenzl, Heimo; Krejs, Guenter J
2017-01-01
D-lactic acidosis is a rare complication that occurs mainly in patients with malabsorption due to a surgically altered gastrointestinal tract anatomy, namely in short bowel syndrome or after bariatric surgery. It is characterized by rapid development of neurological symptoms and severe metabolic acidosis, often with a high serum anion gap. Malabsorbed carbohydrates can be fermented by colonic microbiota capable of producing D-lactic acid. Routine clinical assessment of serum lactate covers only L-lactic acid; when clinical suspicion for D-lactic acidosis is high, special assays for D-lactic acid are called for. A serum level of more than 3 mmol/L of D-lactate confirms the diagnosis. Management includes correction of metabolic acidosis by intravenous bicarbonate, restriction of carbohydrates or fasting, and antibiotics to eliminate intestinal bacteria that produce D-lactic acid. We report a case of D-lactic acidosis in a patient with short bowel syndrome and review the pathophysiology of D-lactic acidosis with its biochemical and clinical features. D-lactic acidosis should be considered when patients with short bowel syndrome or other malabsorption syndromes due to an altered gastrointestinal tract anatomy present with metabolic acidosis and neurological symptoms that cannot be attributed to other causes. With the growing popularity of bariatric surgery, this metabolic derangement may be seen more frequently in the future. © Georg Thieme Verlag KG Stuttgart · New York.
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USDA-ARS?s Scientific Manuscript database
Lactic acid bacteria (LAB) have been widely used in the production of fermented foods and as probiotics. Alternan is a glucan with a distinctive backbone structure of alternating a-(1,6) and a-(1,3) linkages produced by the LAB Leuconostoc mesenteroides. In recent years, we have developed improved...
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USDA-ARS?s Scientific Manuscript database
Lactic acid bacteria (LAB) have been widely used in the production of fermented foods and as probiotics. Alternan is a glucan with a distinctive backbone structure of alternating alpha-(1,6) and alpha-(1,3) linkages produced by the LAB Leuconostoc mesenteroides. In recent years, improved strains f...
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USDA-ARS?s Scientific Manuscript database
Cucumbers are preserved commercially by natural fermentations in 5% to 8% sodium chloride (NaCl) brines. Occasionally, fermented cucumbers spoil after the primary fermentation is complete. This spoilage has been characterized by decreases in lactic acid and a rise in brine pH caused by microbial ins...
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Kim, Yong Seon; Jang, Ji Yeon; Park, Seong Jik; Um, Byung Hwan
2018-04-01
Fermentation of food waste biomass can be used to produce biochemicals such as lactic acid and ethanol in a cost-effective manner. Korean food waste (KFW) dewatered by a screw press contains 23.1% glucan on a dry basis and is a potential raw material for the production of ethanol and lactic acid through fermentation. This study was conducted to optimize the dilute acid fractionation conditions for KFW fermentation with respect to the H 2 SO 4 concentration (0-0.8% w/v), temperature (130-190 °C), and residence time (1-128 min) using response surface methodology. Dilute sulfuric acid fractionation was carried out using a 30-mL stainless steel reactor under conditions, and then the dilute acid fractionation was scaled-up in 1-L and 7-L stainless steel reactors under the optimal conditions. The hydrolysate was concentrated, liquid-liquid extracted and neutralized for lactic acid and ethanol production. The highest concentration of glucose obtained from the KFW was 26.4 g/L using fractionation with 0.37% w/v H 2 SO 4 at 156 °C for 123.6 min. Using recombinant Saccharomyces cerevisiae containing a codon-optimized lactate dehydrogenase, the yield of lactic acid and ethanol was 77% of the theoretical yield for 17.4 g/L of fermentable sugar at pH 5.5. Additionally, the yield of ethanol produced by Issatchenkia orientalis was 89% of the theoretical yield for 25 g/L of fermentable sugar at pH 3. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Zheng, Lu; Bai, Zhongzhong; Xu, Tingting; He, Bingfang
2012-11-01
Sporolactobacillus inulinus, a homofermentative lactic acid bacterium, is a species capable of efficient industrial D-lactic acid production from glucose. Glucose phosphorylation is the key step of glucose metabolism, and fine-tuned expression of which can improve D-lactic acid production. During growth on high-concentration glucose, a fast induction of high glucokinase (GLK) activity was observed, and paralleled the patterns of glucose consumption and D-lactic acid accumulation, while phosphoenolpyruvate phosphotransferase system (PTS) activity was completely repressed. The transmembrane proton gradient of 1.3-1.5 units was expected to generate a large proton motive force to the uptake of glucose. This suggests that the GLK pathway is the major route for glucose utilization, with the uptake of glucose through PTS-independent transport systems and phosphorylation of glucose by GLK in S. inulinus D-lactic acid production. The gene encoding GLK was cloned from S. inulinus and expressed in Escherichia coli. The amino acid sequence revealed significant similarity to GLK sequences from Bacillaceae. The recombinant GLK was purified and shown to be a homodimer with a subunit molecular mass of 34.5 kDa. Strikingly, it demonstrated an unusual broad substrate specificity, catalyzing phosphorylation of 2-deoxyglucose, mannitol, maltose, galactose and glucosamine, in addition to glucose. This report documented the key step concerning glucose phosphorylation of S. inulinus, which will help to understand the regulation of glucose metabolism and D-lactic acid production.
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Structure Study of the Chiral Lactide Molecules by Chirped-Pulse Ftmw Spectroscopy
NASA Astrophysics Data System (ADS)
Zaleski, Daniel P.; Neill, Justin L.; Pate, Brooks H.; Bialkowska-Jaworska, Ewa; Kisiel, Zbigniew
2011-06-01
Lactide is a six member cyclic diester with two chiral centers that forms from lactic acid in the presence of heat and an acid catalyst. It can form either a homo-chiral (RR) structure with both methyl groups equatorial or a hetero-chiral (RS) structure where one methyl group is equatorial and the other methyl group is axial. Structurally lactide is similar to lactic acid dimer; however, the kinked ring is covalently bonded and two waters are lost. And unlike lactic acid dimer, which has a very small dipole moment, the dipole moment of lactide is on the order of 3 Debye. Here the microwave spectra of the highly rigid homo- and hetero-chiral lactides are presented, which were first assigned in a heated lactic acid spectrum where the chemistry took place in the reservoir nozzles. Further isotopic information from a commercial sample of predominately homo-chiral lactide was obtained leading to a Kraitchman substitution structure of the homo-chiral lactide. Preliminary results of the cluster of homo-chiral lactide with one water molecule attached are also presented.
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Watanabe, Masanori; Techapun, Charin; Kuntiya, Ampin; Leksawasdi, Noppol; Seesuriyachan, Phisit; Chaiyaso, Thanongsak; Takenaka, Shinji; Maeda, Isamu; Koyama, Masahiro; Nakamura, Kozo
2017-02-01
A lactic acid producing bacterium, Lactobacillus rhamnosus M-23, newly isolated from a rice washing drainage storage tank was found to produce l-(+)-lactic acid from a non-sterilized mixture of rice washing drainage and rice bran without any additions of nutrients under the simultaneous saccharification and fermentation (SSF) process. This strain has the ability to utilize the non-sterilized rice washing drainage and rice bran as a source of carbohydrate, saccharifying enzymes and nutrients for lactic acid production. Observation of extracellular protease activity in SSF culture broth showed that a higher protease activity was present in strain M-23 than in other isolated lactic acid producing bacteria (LABs). To investigate the structural changes of solid particles of rice washing drainage throughout LAB cultivation, scanning electron microscopic (SEM) observation and Fourier transform infrared-spectroscopy (FT-IR) analysis were performed. The results of the SEM observation showed that the surface material could be removed from solid particles of rice washing drainage treated by culture broth (supernatant) of strain M-23, thus exposing the crystal structure of the starch particle surface. The results of the FT-IR analysis revealed that the specific transmittance decrease of the CC and CO stretching and OH group of the solid particles of the rice washing drainage were highly correlated with the produced lactic acid concentration and extracellular protease activity, respectively. These results demonstrate the high lactic acid producing ability of strain M-23 from a non-sterilized mixture of rice washing drainage and rice bran under the SSF condition due to the removal of proteinaceous material and exposure of the starch particle surface by extracellular protease. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
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Ochi, H; Sakai, Y; Koishihara, H; Abe, F; Bamba, T; Fukusaki, E
2013-01-01
We proposed an application methodology that combines metabolic profiling with multiple appropriate multivariate analyses and verified it on the industrial scale of the ripening process of Cheddar cheese to make practical use of hydrophilic low-molecular-weight compound profiling using gas chromatography-mass spectrometry to design optimal conditions and quality monitoring of the cheese ripening process. Principal components analysis provided an overview of the effect of sodium chloride content and kind of lactic acid bacteria starter on the metabolic profile in the ripening process of Cheddar cheese and orthogonal partial least squares-discriminant analysis unveiled the difference in characteristic metabolites. When the sodium chloride contents were different (1.6 and 0.2%) but the same lactic acid bacteria starter was used, the 2 cheeses were classified by orthogonal partial least squares-discriminant analysis from their metabolic profiles, but were not given perfect discrimination. Not much difference existed in the metabolic profile between the 2 cheeses. Compounds including lactose, galactose, lactic acid, 4-aminobutyric acid, and phosphate were identified as contents that differed between the 2 cheeses. On the other hand, in the case of the same salt content of 1.6%, but different kinds of lactic acid bacteria starter, an excellent distinctive discrimination model was obtained, which showed that the difference of lactic acid bacteria starter caused an obvious difference in metabolic profiles. Compounds including lactic acid, lactose, urea, 4-aminobutyric acid, galactose, phosphate, proline, isoleucine, glycine, alanine, lysine, leucine, valine, and pyroglutamic acid were identified as contents that differed between the 2 cheeses. Then, a good sensory prediction model for "rich flavor," which was defined as "thick and rich, including umami taste and soy sauce-like flavor," was constructed based on the metabolic profile during ripening using partial least squares regression analysis. The amino acids proline, leucine, valine, isoleucine, pyroglutamic acid, alanine, glutamic acid, glycine, lysine, tyrosine, serine, phenylalanine, methionine, aspartic acid, and ornithine were extracted as ripening process markers. The present study is not limited to Cheddar cheese and can be applied to various maturation-type natural cheeses. This study provides the technical platform for designing optimal conditions and quality monitoring of the cheese ripening process. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
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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.
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Nguyen, Cuong Mai; Kim, Jin-Seog; Song, Jae Kwang; Choi, Gyung Ja; Choi, Yong Ho; Jang, Kyoung Soo; Kim, Jin-Cheol
2012-12-01
D-lactic acid production from dry biomass of the microalga, Hydrodictyon reticulatum, was carried out in a 5-l jar fermentor (initial pH 6, 34 °C using CaCO(3) as a neutralizing agent) through simultaneous saccharification and co-fermentation using the Lactobacillus coryniformis subsp. torquens. After 36 h, 36.6 g lactic acid/l was produced from 80 g H. reticulatum/l in the medium containing 3 g yeast extract/l and 3 g peptone/l in the absence of mineral salts. The maximum productivity, average productivity and yield were 2.38 g/l h, 1.02 g/l h and 45.8 %, respectively. The optical purity of D-Lactic acid ranged from 95.8-99.6 %. H. reticulatum is thus a promising biomass material for the production of D-Lactic acid.
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Witkin, Steven S
2018-05-01
Women are unique from all other mammals in that lactic acid is present at high levels in the vagina during their reproductive years. This dominance may have evolved in response to the unique human lifestyle and a need to optimally protect pregnant women and their fetuses from endogenous and exogenous insults. Lactic acid in the female genital tract inactivates potentially pathogenic bacteria and viruses, maximizes survival of vaginal epithelial cells, and inhibits inflammation that may be damaging to the developing fetus and maintenance of the pregnancy. In an analogous manner, lactic acid production facilitates survival of malignantly transformed cells, inhibits activation of immune cells, and prevents the release of pro-inflammatory mediators in response to tumor-specific antigens. Thus, the same stress-reducing properties of lactic acid that promote lower genital tract health facilitate malignant transformation and progression.
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USDA-ARS?s Scientific Manuscript database
In order to understand the origin of the tacticity splitting in the NMR spectrum of poly(lactic acid), monomer model compound and dimer model compounds (both isotactic and syndiotactic) were synthesized and their 1H and 13C NMR chemical shifts observed. Two energetically stable conformations were o...
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USDA-ARS?s Scientific Manuscript database
In this study poly(lactic acid)(PLA) and polyvinylpyrrolidone (PVP) micro and nanofibers mats loaded with copaiba (Copaifera sp.) oil were produced by solution blow spinning (SBS). The copaiba (Copaifera sp.) oil was characterized by gas chromatography (GC). Neat PLA and four PLA/ PVP blends contain...
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Deng, Meng; Nair, Lakshmi S.; Nukavarapu, Syam P.; Kumbar, Sangamesh G.; Jiang, Tao; Krogman, Nicholas R.; Singh, Anurima; Allcock, Harry R.; Laurencin, Cato T.
2007-01-01
Previously we demonstrated the ability of ethyl glycinato substituted polyphosphazenes to neutralize the acidic degradation products and control the degradation rate of poly(lactic acid-glycolic acid) by blending. In this study, blends of high strength poly[(50% ethyl alanato) (50% p-phenyl phenoxy) phosphazene] (PNEA50PhPh50) and 85:15 poly(lactic acid-glycolic acid) (PLAGA) were prepared using a mutual solvent approach. Three different solvents, methylene chloride (MC), chloroform (CF) and tetrahydrofuran (THF) were studied to investigate solvent effects on blend miscibility. Three different blends were then fabricated at various weight ratios namely 25:75 (BLEND25), 50:50 (BLEND50), and 75:25 (BLEND75) using THF as the mutual solvent. The miscibility of the blends was evaluated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). Among these, BLEND25 was miscible while BLEND50 and BLEND75 were partially miscible. Furthermore, BLEND25 formed apatite layers on its surface as evidenced in a biomimetic study performed. These novel blends showed cell adhesion and proliferation comparable to PLAGA. However, the PNEA50PhPh50 component in the blends was able to increase the phenotypic expression and mineralized matrix synthesis of the primary rat osteoblasts (PRO) in vitro. Blends of high strength poly[(50% ethyl alanato) (50% p-phenyl phenoxy) phosphazene] (PNEA50PhPh50) and 85:15 poly(lactic acid-glycolic acid) (PLAGA) are promising biomaterials for a variety of musculoskeletal applications. PMID:17942150
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Bowman, John P.; Ratkowsky, David A.; Tamplin, Mark
2017-01-01
Carnobacterium maltaromaticum is frequently associated with foods having extended shelf-life due to its inhibitory activity to other bacteria. The quantification of such inhibition interactions affected by various environmental factors is limited. This study investigated the effect of environmental factors relevant to vacuum-packaged beef on inhibition between two model isolates of C. maltaromaticum, D0h and D8c, specifically D8c sensitivity to D0h inhibition and D0h inhibitor production. The effects of temperature (−1, 7, 15, 25 °C), atmosphere (aerobic and anaerobic), pH (5.5, 6, 6.5), lactic acid (0, 25, 50 mM) and glucose (0, 0.56, 5.55 mM) on D8c sensitivity (diameter of an inhibition zone) were measured. The effects of pH, glucose, lactic acid and atmosphere on D0h inhibitor production were measured at 25 °C. Sensitivity of D8c was the highest at 15 °C, under aerobic atmosphere, at higher concentrations of undissociated lactic acid and glucose, and at pH 5.5 (p < 0.001). pH significantly affected D0h inhibitor production (p < 0.001), which was the highest at pH 6.5. The effect of lactic acid depended upon pH level; at relatively low pH (5.5), lactic acid decreased the production rate (arbitrary inhibition unit (AU)/mL/h). This study provides a quantitative description of intra-species interactions, studied in in vitro environments that are relevant to vacuum-packaged beef. PMID:28906433
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21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.
Code of Federal Regulations, 2012 CFR
2012-04-01
... esters of fatty acids (the lactic acid esters of mono- and diglycerides) may be safely used in food in accordance with the following prescribed conditions: (a) They are manufactured from glycerin, lactic acid...
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21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.
Code of Federal Regulations, 2013 CFR
2013-04-01
... esters of fatty acids (the lactic acid esters of mono- and diglycerides) may be safely used in food in accordance with the following prescribed conditions: (a) They are manufactured from glycerin, lactic acid...
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21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.
Code of Federal Regulations, 2011 CFR
2011-04-01
... esters of fatty acids (the lactic acid esters of mono- and diglycerides) may be safely used in food in accordance with the following prescribed conditions: (a) They are manufactured from glycerin, lactic acid...
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Li, Chao; Tao, Fei; Xu, Ping
2016-08-17
High production of polymer-grade d-lactic acid is urgently required, particularly for the synthesis of polylactic acid. High-temperature fermentation has multiple advantages, such as lower equipment requirement and energy consumption, which are essential for lowering operating costs. We identified and introduced a unique d-lactate dehydrogenase into a thermotolerant butane-2,3-diol-producing strain. Carbon flux "trapping" was achieved by a "trapping point" created by combination of the introduced enzyme and the host efflux pump, which afforded irreversible transport of d-lactic acid. The overall carbon flux of the engineered strain was significantly enhanced and was redistributed predominantly to d-lactic acid. Under optimized conditions at 50 °C, d-lactic acid reached the highest titer (226.6 g L(-1) ) reported to date. This discovery allows us to extend the carbon flux trapping strategy to engineering complex metabolic networks. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Vaginal pH and Microbicidal Lactic Acid When Lactobacilli Dominate the Microbiota
O’Hanlon, Deirdre E.; Moench, Thomas R.; Cone, Richard A.
2013-01-01
Lactic acid at sufficiently acidic pH is a potent microbicide, and lactic acid produced by vaginal lactobacilli may help protect against reproductive tract infections. However, previous observations likely underestimated healthy vaginal acidity and total lactate concentration since they failed to exclude women without a lactobacillus-dominated vaginal microbiota, and also did not account for the high carbon dioxide, low oxygen environment of the vagina. Fifty-six women with low (0-3) Nugent scores (indicating a lactobacillus-dominated vaginal microbiota) and no symptoms of reproductive tract disease or infection, provided a total of 64 cervicovaginal fluid samples using a collection method that avoided the need for sample dilution and rigorously minimized aerobic exposure. The pH of samples was measured by microelectrode immediately after collection and under a physiological vaginal concentration of CO2. Commercial enzymatic assays of total lactate and total acetate concentrations were validated for use in CVF, and compared to the more usual HPLC method. The average pH of the CVF samples was 3.5 ± 0.3 (mean ± SD), range 2.8-4.2, and the average total lactate was 1.0% ± 0.2% w/v; this is a five-fold higher average hydrogen ion concentration (lower pH) and a fivefold higher total lactate concentration than in the prior literature. The microbicidal form of lactic acid (protonated lactic acid) was therefore eleven-fold more concentrated, and a markedly more potent microbicide, than indicated by prior research. This suggests that when lactobacilli dominate the vaginal microbiota, women have significantly more lactic acid-mediated protection against infections than currently believed. Our results invite further evaluations of the prophylactic and therapeutic actions of vaginal lactic acid, whether provided in situ by endogenous lactobacilli, by probiotic lactobacilli, or by products that reinforce vaginal lactic acid. PMID:24223212
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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.
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Characterization of lactic acid bacteria from local cow´s milk kefir
NASA Astrophysics Data System (ADS)
Ismail, YS; Yulvizar, C.; Mazhitov, B.
2018-03-01
One of products from milk fermentation is kefir. It is made by adding kefir grains which are composed of lactic acid bacteria and yeast into milk. The lactic acid bacteria are a group of bacteria that produce antimicrobial substances and able to inhibit the growth of pathogenic bacteria. In this research, the lactic acid bacteria were isolated from Aceh local cow`s milk kefir to determine the genus of the isolates. The methods used in the characterization of lactic acid bacteria are colony morphology, cell morphology, and biochemical tests which includes a catalase test; 5%, 6.5%, and 10% salt endurance tests; 37°C and 14°C temperature endurance tests, SIM test, TSIA test, MR-VP test, and O/F test. Of the four isolates found from the cow’s milk kefir, two isolates were confirmed as lactic acid bacteria (isolates SK-1 and SK-4). Both isolates are Gram positive bacteria, and have negative catalase activity. From the observations of colony morphology, cell morphology, and biochemical tests, it was found that the genus of SK-1 is Lactobacillus and the genus of SK-4 is Enterococcus.
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Li, Shuliu; Kundu, Devapriya; Holley, Richard A
2015-04-01
Lactic acid pre-treatment was examined to enhance the antimicrobial action of electron (e-) beam irradiation of beef trim. Meat samples were inoculated with Escherichia coli O157:H7, non-O157 VTEC E. coli or Salmonella cocktails and treated with 5% lactic acid at 55 °C. Samples were packaged aerobically or vacuum-packed, kept at 4 °C and treated with 1 kGy e-beam energy. Frozen samples were treated with 1, 3 or 7 kGy and stored at -20 °C for ≤ 5 d. Lactic acid enhanced the antimicrobial action of 1 kGy e-beam treatment against Salmonella by causing an additional <1.8 log CFU/g reduction. One kGy treatment of refrigerated samples reduced VTEC E. coli viability by 4.5 log CFU/g, and while lactic acid did not improve the reduction, after freezing additive effects were found. After 3 kGy irradiation, Salmonella was reduced by 2 and 4 log CFU/g in the irradiated and lactic acid plus irradiated samples, respectively. Lactic acid pre-treatment was of limited value with 1 kGy treatment for improving control of toxigenic E. coli in fresh beef trim, however, it would be useful with low dose irradiation for controlling both VTEC E. coli and Salmonella in frozen product. Copyright © 2014 Elsevier Ltd. All rights reserved.
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DNA Fingerprinting of Lactic Acid Bacteria in Sauerkraut Fermentations▿ † ‡
Plengvidhya, Vethachai; Breidt, Fredrick; Lu, Zhongjing; Fleming, Henry P.
2007-01-01
Previous studies using traditional biochemical identification methods to study the ecology of commercial sauerkraut fermentations revealed that four species of lactic acid bacteria, Leuconostoc mesenteroides, Lactobacillus plantarum, Pediococcus pentosaceus, and Lactobacillus brevis, were the primary microorganisms in these fermentations. In this study, 686 isolates were collected from four commercial fermentations and analyzed by DNA fingerprinting. The results indicate that the species of lactic acid bacteria present in sauerkraut fermentations are more diverse than previously reported and include Leuconostoc citreum, Leuconostoc argentinum, Lactobacillus paraplantarum, Lactobacillus coryniformis, and Weissella sp. The newly identified species Leuconostoc fallax was also found. Unexpectedly, only two isolates of P. pentosaceus and 15 isolates of L. brevis were recovered during this study. A better understanding of the microbiota may aid in the development of low-salt fermentations, which may have altered microflora and altered sensory characteristics. PMID:17921264
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Łukasik, J; Salminen, S; Szajewska, H
2018-03-30
Extensive ongoing research on probiotics and infant formulas raises a number of safety questions. One concern is the potential influence of d-lactic acid-containing preparations on the health of infants and children. The aim of this review was to summarise the available knowledge on the ingestion of d-lactic acid-producing bacteria, acidified infant formulas and fermented infant formulas as a potential cause of paediatric d-lactic acidosis. A Medline database search was performed in July 2017, with no restrictions on the language, article type or publication date. The 1715 search results were screened for clinical trials, review articles, case series and case reports of relevance to the topic. We identified five randomised controlled trials from 2005 to 2017 covering 544 healthy infants and some case reports and experimental studies. No clinically relevant adverse effects of d-lactic acid-producing probiotics and fermented infant formulas were described in healthy children. However, a harmless, subclinical accumulation of d-lactate was theoretically possible. The only known cases of paediatric d-lactic acidosis occurred in patients with short bowel syndrome or, historically, in infants fed with acidified formulas. Our main finding was that probiotics and fermented formulas did not cause d-lactic acidosis in healthy children. ©2018 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.
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Li, Chao; Gai, Zhongchao; Wang, Kai; Jin, Liping
2017-01-01
Bacillus licheniformis MW3 as a GRAS and thermophilic strain is a promising microorganism for chemical and biofuel production. However, its capacity to co-utilize glucose and xylose, the major sugars found in lignocellulosic biomass, is severely impaired by glucose-mediated carbon catabolite repression (CCR). In this study, a "dual-channel" process was implemented to engineer strain MW3 for simultaneous utilization of glucose and xylose, using l-lactic acid as a target product. A non-phosphotransferase system (PTS) glucose uptake route was activated via deletion of the glucose transporter gene ptsG and introduction of the galactose permease gene galP . After replacing the promoter of glucokinase gene glck with the strong promoter P als , the engineered strain recovered glucose consumption and utilized glucose and xylose simultaneously. Meanwhile, to improve the consumption rate of xylose in this strain, several measures were undertaken, such as relieving the regulation of the xylose repressor XylR, reducing the catabolite-responsive element, and optimizing the rate-limiting step. Knockout of ethanol and acetic acid pathway genes further increased lactic acid yield by 6.2%. The resultant strain, RH15, was capable of producing 121.9 g/L l-lactic acid at high yield (95.3%) after 40 h of fermentation from a mixture of glucose and xylose. When a lignocellulosic hydrolysate was used as the substrate, 99.3 g/L l-lactic acid was produced within 40 h, with a specific productivity of 2.48 g/[L h] and a yield of 94.6%. Our engineered strain B. licheniformis RH15 could thermophilically produced l-lactic acid from lignocellulosic hydrolysate with relatively high concentration and productivity at levels that were competitive with most reported cases of l-lactic acid-producers. Thus, the engineered strain might be used as a platform for the production of other chemicals. In addition to engineering the B. licheniformis strain, the "dual-channel" process might serve as an alternative method for engineering a variety of other strains.
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Jeong, Kyung Hun; Israr, Beenish; Shoemaker, Sharon P; Mills, David A; Kim, Jaehan
2016-07-28
Lactobacillus brevis ATCC 14869 exhibited a carbon catabolite de-repressed (CCR) phenotype which has ability to consume fermentable sugar simultaneously with glucose. To evaluate this unusual phenotype under harsh conditions during fermentation, the effect of lactic acid and hydrogen ion concentrations on L. brevis ATCC 14869 were examined. Kinetic equations describing the relationship between specific cell growth rate and lactic acid or hydrogen ion concentration has been reduced. The change of substrate utilization and product formation according to lactic acid and hydrogen ion concentration in the media were quantitatively described. Moreover; utilization of other compounds were also observed along with hydrogen ion and lactic acid concentration simultaneously. It has been found that substrate preference changes significantly regarding to utilization of compounds in media. That could result into formation of two-carbon products. In particular, acetic acid present in the media as sodium acetate were consumed by L. brevis ATCC 14869 under extreme pH of both acid and alkaline conditions.
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King, Amanda M; Miller, Rhonda K; Castillo, Alejandro; Griffin, Davey B; Hardin, Margaret D
2012-09-01
Current industry chilling practices with and without the application of 2% L-lactic acid were compared for their effectiveness at reducing levels of Salmonella, Yersinia enterocolitica, and Campylobacter coli on pork variety meats. Pork variety meats (livers, intestines, hearts, and stomachs) were inoculated individually with one of the three pathogens and subjected to five different treatment combinations that included one or more of the following: water wash (25°C), lactic acid spray (2%, 40 to 50°C), chilling (4°C), and freezing (-15°C). Samples were analyzed before treatment, after each treatment step, and after 2, 4, and 6 months of frozen storage. Results showed that when a lactic acid spray was used in combination with water spray, immediate reductions were approximately 0.5 log CFU per sample of Salmonella, 0.8 log CFU per sample of Y. enterocolitica, and 1.1 log CFU per sample of C. coli. Chilling, both alone and in combination with spray treatments, had little effect on pathogens, while freezing resulted in additional 0.5-log CFU per sample reductions in levels of Salmonella and Y. enterocolitica, and an additional 1.0-log CFU per sample reduction in levels of C. coli. While reductions of at least 1 log CFU per sample were observed on variety meats treated with only a water wash and subsequently frozen, samples treated with lactic acid had greater additional reductions than those treated with only a water spray throughout frozen storage. The results of this study suggest that the use of lactic acid as a decontamination intervention, when used in combination with good manufacturing practices during processing, causes significant reductions in levels of Salmonella, Y. enterocolitica, and C. coli on pork variety meats.
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D-lactic acid interferes with the effects of platelet activating factor on bovine neutrophils.
Alarcón, P; Conejeros, I; Carretta, M D; Concha, C; Jara, E; Tadich, N; Hidalgo, M A; Burgos, R A
2011-11-15
D-lactic acidosis occurs in ruminants, such as cattle, with acute ruminal acidosis caused by ingestion of excessive amounts of highly fermentable carbohydrates. Affected animals show clinical signs similar to those of septic shock, as well as acute laminitis and liver abscesses. It has been proposed that the inflammatory response and susceptibility to infection could both be caused by the inhibition of phagocytic mechanisms. To determine the effects of d-lactic acid on bovine neutrophil functions, we pretreated cells with different concentrations of D-lactic acid and measured intracellular pH using 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM) and calcium flux using FLUO-3 AM-loaded neutrophils. Reactive oxygen species (ROS) production was measured using a luminol chemiluminescence assay, and MMP-9/gelatinase-B granule release was measured by zymography. CD11b and CD62L/l-selectin expression, changes in cell shape, superoxide anion production, phagocytosis of Escherichia coli-Texas red bioparticles, and apoptosis were all measured using flow cytometry. Our results demonstrated that D-lactic acid reduced ROS production, CD11b upregulation and MMP-9 release in bovine neutrophils treated with 100 nM platelet-activating factor (PAF). D-lactic acid induced MMP-9 release and, at higher concentrations, upregulated CD11b expression, decrease L-selectin expression, and induces late apoptosis. We concluded that D-lactic acid can interfere with neutrophil functions induced by PAF, leading to reduced innate immune responses during bacterial infections. Moreover, the increase of MMP-9 release and CD11b expression induced by 10mM D-lactic acid could promote an nonspecific neutrophil-dependent inflammatory reaction in cattle with acute ruminal acidosis. Copyright © 2011 Elsevier B.V. All rights reserved.
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D-lactic acidosis in humans: systematic literature review.
Bianchetti, Davide G A M; Amelio, Giacomo S; Lava, Sebastiano A G; Bianchetti, Mario G; Simonetti, Giacomo D; Agostoni, Carlo; Fossali, Emilio F; Milani, Gregorio P
2018-04-01
D-lactic acidosis is an uncommon and challenging form of metabolic acidosis that may develop in short bowel syndrome. It has been documented exclusively in case reports and small case series. We performed a review of the literature in the National Library of Medicine and Excerpta Medica databases. We identified 84 original reports published between 1977 and 2017. D-lactic acidosis was observed in 98 individuals ranging in age from 7 months to 86 years with short bowel syndrome. The clinical presentation included Kussmaul breathing, confusion, slurred speech, and gait disturbances. Furthermore, among 99 consecutive patients with short bowel syndrome, 21 reported having episodes with symptoms consistent with D-lactic acidosis. In addition, D-lactic acid might also contribute to acidosis in diabetes mellitus. Finally, abnormally high D-lactic acid was documented after administration or ingestion of large amounts of propylene glycol, as paraneoplastic phenomenon and perhaps also in a so far poorly characterized inherited inborn error of metabolism. In humans with short bowel syndrome (or carbohydrate malabsorption), D-lactic acidosis is likely rather common and under-recognized. This condition should be included in the differential diagnosis of unexplained high-gap metabolic acidosis where the anion causing the acidosis is not known. Furthermore, diabetic acidosis might be caused by accumulation of both ketone bodies and D-lactic acid. Finally, there are endogenous sources of D-lactic acid in subjects with propylene glycol intoxication.
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USDA-ARS?s Scientific Manuscript database
The miscibility of blends of poly(lactic acid) (PLA) and poly(ethylene oxide) (PEO) was studied in polymer solutions by dilute solution viscometry and in solution blow spun nanofibers by microscopy (SEM, TEM) and by thermal and spectral analysis. Three blends of PLA and PEO were solution blended in...
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Aerobic stability of maize silage stored under plastic films with different oxygen permeability.
Borreani, Giorgio; Piano, Serenella; Tabacco, Ernesto
2014-10-01
The most important factor that can influence silage quality is the degree of anaerobiosis maintained during conservation. The quality of the plastic film is a key factor, since the permeability of polyethylene to oxygen is too high for silage conservation. The aim of this work was to assess the effects of the interaction between three plastic films with different degrees of oxygen permeability and two different maize silage conservation times on fermentation, microbial quality and aerobic stability. The conservation time affected the pH, lactic and acetic acids, 1,2-propanediol and lactic/acetic acid ratio, with higher pH, lower lactic acid concentration and lactic/acetic acid ratio but higher acetic acid and 1,2-propanediol concentrations being found in silages conserved for 110 days versus silages conserved for 55 days. The plastic film affected the pH, lactic and acetic acids and lactic/acetic acid ratio. The yeast count was lower and aerobic stability higher for silage conserved under the oxygen barrier film for both conservation periods. The positive interaction between length of storage and the increased anaerobiosis of silage during conservation provided by the oxygen barrier compared with polyethylene film helped reduce the yeast count and increase the aerobic stability of maize silage, even when less acetic acid was produced during ensiling. © 2014 Society of Chemical Industry.
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RoushanZadeh, S; Eskandari, M. H.; Shekarforoush, S. S.; Hosseini, A
2014-01-01
Morphological, biochemical and molecular characteristics were studied to identify dominant lactic acid bacteria (LAB), isolated from traditional yoghurts produced by tribes of Iran. From 60 yoghurt samples, a total of 137 LAB isolates were determined, in which 66 and 71 were identified as lactic acid cocci and bacilli, respectively. Biochemical tests showed the occurrence of 9.76% mesophilic homofermentative, 10.98% mesophilic hetrofermentative, 26.83% thermophilic homofermentative and 47.56% mesophilic homofermentative cocci. As for lactic acid bacilli, mesophilic facultative hetrofermentative (26%); thermophilic obligate homofermentative (56%); mesophilic obligate hetrofermentative (18%) were found. Genetically the presence of the following species were verified: E. faecium; E. faecalis; E. durans; L. lactis subsp. lactis; St. thermophilus; Lb. delbruecki subsp. bulgaricus; Lb. brevis; Lb. diolivorans; Lb. helveticus; Lb. jensenii; Lb. plantarum. 9% of the Lactobacillus isolates showed incompatible results between phenotypic and genotypic characteristics. From the cocci isolates, 38.46% showed identical results between phylogenetic characteristics. The current study constitutes the first step in the designing process of LAB starter cultures, to protect the typical organoleptic characteristics of traditional yoghurt. The results could also be used to introduce new starter cultures for commercial use. PMID:27175129
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Liu, Linshu; Jin, Tony Z; Coffin, David R; Hicks, Kevin B
2009-09-23
Nisin is a naturally occurring antimicrobial polypeptide and is popularly used in the food and food-packaging industries. Nisin is deactivated at temperatures higher than 120 degrees C and, therefore, cannot be directly incorporated into poly(L-lactic acid) (PLA), a biomass-derived biodegradable polymer, by coextrusion because PLA melts at temperatures around 160 degrees C or above. However, PLA can remain in a melt state at temperatures below the T(m) in the presence of lactic acid or other plasticizers. In the present study, PLA was coextruded with lactic acid, or lactide, or glycerol triacetate at 160 degrees C. After the PLA was melted, the temperature of the barrels was reduced to 120 degrees C, and then Nisaplin, the commercial formulation of nisin, was added and the extrusion was continued. The resultant extrudates possess the capability to suppress the growth of the pathogenic bacterial Listeria monocytogenes , demonstrating a significant antimicrobial activity. The present study provides a simple method to produce PLA-based antimicrobial membranes. The method can also be used for the coextrusion of other heat-sensitive substances and thermoplastics with high melting temperature.
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Electron transport chains of lactic acid bacteria - walking on crutches is part of their lifestyle
Brooijmans, Rob; Hugenholtz, Jeroen
2009-01-01
A variety of lactic acid bacteria contain rudimentary electron transport chains that can be reconstituted by the addition of heme and menaquinone to the growth medium. These activated electron transport chains lead to higher biomass production and increased robustness, which is beneficial for industrial applications, but a major concern when dealing with pathogenic lactic acid bacteria. PMID:20948651
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Materials and methods for efficient lactic acid production
Zhou, Shengde; Ingram, Lonnie O& #x27; Neal; Shanmugam, Keelnatham T; Yomano, Lorraine; Grabar, Tammy B; Moore, Jonathan C
2013-04-23
The present invention provides derivatives of Escherichia coli constructed for the production of lactic acid. The transformed E. coli of the invention are prepared by deleting the genes that encode competing pathways followed by a growth-based selection for mutants with improved performance. These transformed E. coli are useful for providing an increased supply of lactic acid for use in food and industrial applications.
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Materials and methods for efficient lactic acid production
Zhou, Shengde [Sycamore, IL; Ingram, Lonnie O'Neal [Gainesville, FL; Shanmugam, Keelnatham T [Gainesville, FL; Yomano, Lorraine [Gainesville, FL; Grabar, Tammy B [Gainesville, FL; Moore, Jonathan C [Gainesville, FL
2009-12-08
The present invention provides derivatives of ethanologenic Escherichia coli K011 constructed for the production of lactic acid. The transformed E. coli of the invention are prepared by deleting the genes that encode competing pathways followed by a growth-based selection for mutants with improved performance. These transformed E. coli are useful for providing an increased supply of lactic acid for use in food and industrial applications.
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Synthesis of PDLLA/PLLA-bentonite nanocomposite through sonication
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sitompul, Johnner, E-mail: sitompul@che.itb.ac.id; Setyawan, Daru, E-mail: daru.setyawan@gmail.com; Kim, Daniel Young Joon, E-mail: daniel.kim12321@gmail.com
2016-04-19
This paper concerns the synthesis of poly(D,L-lactic acid)/poly(L-lactic acid) bentonite nanocomposites. Poly (D,L-lactic acid) (PDLLA) was synthesized using lactic acid through the ZnO-catalyzed direct polycondensation method at vacuum pressure and poly(L-lactic acid) (PLLA) was synthesized with L-lactide by ring-opening polymerization method. The PDLLA/PLLA-bentonite nanocomposite films were synthesized using the solvent casting method. The nanoclay, bentonite, was prepared using the solution-intercalation method by dissolving the nanoparticles into chloroform before sonication. In this study, PDLLA/PLLA-bentonite nanocomposite films were produced using variable amounts of nanoclay and sonication times during the mixing of PDLLA/PLLA and bentonite. The properties of the PDLLA/PLLA nanocomposites were thenmore » characterized using the X-ray Diffraction (XRD), Universal Testing Machine (UTM), Water Vapor Permeability (WVP) tests, and the enzymatic biodegradability test. The XRD test was used to measure the intercalation of nanoclay layers in the PDLLA/PLLA matrix and the PDLLA/PLLA-bentonite intercalated nanocomposite films. It was found through these various tests that adding bentonite to the PDLLA/PLLA increases tensile strength to 56.76 MP. Furthermore, the biodegradability increases as well as the barrier properties of the polymers The different sonication time used during the mixing of the polymer solution with bentonite also affected the properties of the PDLLA/PLLA-bentonite nanocomposite films.« less
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Metronidazole with Lactacyd vaginal gel in bacterial vaginosis.
Decena, Ditas Cristina D; Co, Jennifer T; Manalastas, Ricardo M; Palaypayon, Evelyn P; Padolina, Christia S; Sison, Judith M; Dancel, Louella A; Lelis, Marievi A
2006-04-01
To assess the efficacy and tolerability of lactic acid (Lactacyd vaginal gel; LVG) when given as an adjunct to metronidazole in the treatment of bacterial vaginosis (BV) among Filipino patients. A multicenter, open-labeled, controlled, randomized, three-arm comparative study on 90 women aged 18 years or over with clinically and microbiologically proven BV. The lactobacilli colony count significantly increased over time in all three arms. At day 14, growth of lactobacilli was significantly higher among patients in the lactic acid gel and combination treatment arms. Significant reduction of malodorous vaginal discharge (whiff test) and lowest recurrence of BV were noted in the metronidazole plus lactic acid gel arm. Regarding disappearance of signs of BV, there was significant decrease in the pH level and frequency of clue cell positive patients across time but was not significantly different across treatment groups. Only one patient (3%, 1/60) among those who received lactic acid gel complained of increased curd-like discharge. Six patients (10%, 6/60) who received metronidazole complained of epigastric pain/discomfort, dizziness and dyspnea. Lactic acid gel (LVG) is safe and as efficacious as metronidazole in the treatment of BV. There is evidence that LVG when combined with metronidazole is superior to metronidazole alone in promoting lactobacilli colonization. LVG as an adjunct to metronidazole, having the least number of recurrent BV, appears to result in better long-term treatment effect on bacterial vaginosis.
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Acetate accumulation enhances mixed culture fermentation of biomass to lactic acid.
Khor, Way Cern; Roume, Hugo; Coma, Marta; Vervaeren, Han; Rabaey, Korneel
2016-10-01
Lactic acid is a high-in-demand chemical, which can be produced through fermentation of lignocellulosic feedstock. However, fermentation of complex substrate produces a mixture of products at efficiencies too low to justify a production process. We hypothesized that the background acetic acid concentration plays a critical role in lactic acid yield; therefore, its retention via selective extraction of lactic acid or its addition would improve overall lactic acid production and eliminate net production of acetic acid. To test this hypothesis, we added 10 g/L of acetate to fermentation broth to investigate its effect on products composition and concentration and bacterial community evolution using several substrate-inoculum combinations. With rumen fluid inoculum, lactate concentrations increased by 80 ± 12 % (cornstarch, p < 0.05) and 16.7 ± 0.4 % (extruded grass, p < 0.05) while with pure culture inoculum (Lactobacillus delbrueckii and genetically modified (GM) Escherichia coli), a 4 to 23 % increase was observed. Using rumen fluid inoculum, the bacterial community was enriched within 8 days to >69 % lactic acid bacteria (LAB), predominantly Lactobacillaceae. Higher acetate concentration promoted a more diverse LAB population, especially on non-inoculated bottles. In subsequent tests, acetate was added in a semi-continuous percolation system with grass as substrate. These tests confirmed our findings producing lactate at concentrations 26 ± 5 % (p < 0.05) higher than the control reactor over 20 days operation. Overall, our work shows that recirculating acetate has the potential to boost lactic acid production from waste biomass to levels more attractive for application.
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N'tcha, Christine; Sina, Haziz; Kayodé, Adéchola Pierre Polycarpe; Gbenou, Joachim D; Baba-Moussa, Lamine
2017-01-01
The aim of this study was to investigate the antibacterial effect of the crude starter " kpètè-kpètè " and lactic acid bacteria used during the production of "tchoukoutou." To achieve this, a total of 11 lactic acid bacteria and 40 starter samples were collected from four communes. The samples were tested on 29 gram + and - strains by disk diffusion method. The minimum inhibitory and bactericidal concentrations of starter and lactic acid bacteria were determined by conventional methods. Organic acids, sugar, and volatile compounds were determined using the HPLC method. The "kpètè-kpètè" displays a high antibacterial activity against the tested strains. The most sensitive strain was S. epidermidis (12.5 mm) whereas the resistance strain was Proteus mirabilis (8 mm). All the tested ferment has not any inhibitory effect on Enterococcus faecalis . The lactic acid bacteria isolates of Parakou showed the highest (17.48 mm) antibacterial activity whereas the smallest diameter was obtained with the ferment collected from Boukoumbé (9.80 mm). The starters' chemical screening revealed the presence of tannins, anthocyanin flavonoids, triterpenes, steroids, reducing compounds, and mucilage O-glycosides. These compounds are probably the source of recorded inhibition effect. The lactic acid bacteria of the "kpètè-kpètè" could be used to develop a food ingredient with probiotic property.
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Yokoyama, Yukihiro; Mizuno, Takashi; Sugawara, Gen; Asahara, Takashi; Nomoto, Koji; Igami, Tsuyoshi; Ebata, Tomoki; Nagino, Masato
2017-10-01
To investigate the association between preoperative fecal organic acid concentrations and the incidence of postoperative infectious complications in patients undergoing major hepatectomy with extrahepatic bile duct resection for biliary malignancies. The fecal samples of 44 patients were collected before undergoing hepatectomy with bile duct resection for biliary malignancies. The concentrations of fecal organic acids, including acetic acid, butyric acid, and lactic acid, and representative fecal bacteria were measured. The perioperative clinical characteristics and the concentrations of fecal organic acids were compared between patients with and without postoperative infectious complications. Among 44 patients, 13 (30%) developed postoperative infectious complications. Patient age and intraoperative bleeding were significantly greater in patients with postoperative infectious complications compared with those without postoperative infectious complications. The concentrations of fecal acetic acid and butyric acid were significantly less, whereas the concentration of fecal lactic acid tended to be greater in the patients with postoperative infectious complications. The calculated gap between the concentrations of fecal acetic acid plus butyric acid minus lactic acid gap was less in the patients with postoperative infectious complications (median 43.5 vs 76.1 μmol/g of feces, P = .011). Multivariate analysis revealed that an acetic acid plus butyric acid minus lactic acid gap <60 μmol/g was an independent risk factor for postoperative infectious complications with an odds ratio of 15.6; 95% confidence interval 1.8-384.1. The preoperative fecal organic acid profile (especially low acetic acid, low butyric acid, and high lactic acid) had a clinically important impact on the incidence of postoperative infectious complications in patients undergoing major hepatectomy with extrahepatic bile duct resection. Copyright © 2017. Published by Elsevier Inc.
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Karaduman, Ayse; Ozaslan, Mehmet Ozaslan; Kilic, Ibrahim H; Bayil-Oguzkan, Sibel; Kurt, Bekir S; Erdogan, Nese
2017-03-01
Yogurt is a dairy product obtained by bacterial fermentation of milk. Commercial yogurts are produced using standard starters while, in the production of non-commercial yogurt, the microbiota is quite different since yogurts are used as starter for years. To determine the final characteristics of the fermented product it is necessary to know the biochemical properties of the starter cultures, such as acidity, aroma and flavor. This can only be achieved by identifying and characterizing the bacteria in starter cultures. In our study, 208 non-commercial yogurt samples were collected from 9 different locations in Anatolia, southern Turkey. Their pH and lactic acid bacteria profiles were analyzed. Isolated bacteria were identified by MALDI-TOF MS (matrix-assisted laser sesorption-ionization time-of-flight, mass spectrometry), which is a fast and reliable method for identification of bacterial isolates compared to classical laboratory methods. In this study, 41% of the isolates were identified by using this method, which is 99.9% and 34.0% confidence. The isolates contained two genera (Enterococcus and Lactobacillus) and four species. Afterwards, the four lactic acid bacteria were characterized physiologically and biochemically and we found that they differed from lactic acid bacteria used in commercial yogurt production. [Int Microbiol 20(1): 25-30 (2017)]. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.
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NASA Astrophysics Data System (ADS)
Hidayat, Habibi
2017-03-01
16S rRNA gene analysis of bacteria lactic acid (LAB) isolate from Markisa Kuning Fruit (Passiflora edulis var. flavicarpa) as a producer of protease enzyme and probiotics has been done. The aim of the study is to determine the protease enzyme activity and 16S rRNA gene amplification using PCR. The calculation procedure was done to M4 isolate bacteria lactic acid (LAB) Isolate which has been resistant to acids with pH 2.0 in the manner of screening protease enzyme activity test result 6.5 to clear zone is 13 mm againts colony diametre is 2 mm. The results of study enzyme activity used spectrophotometer UV-Vis obtainable the regression equation Y=0.02983+0.001312X, with levels of protein M4 isolate is 0.6594 mg/mL and enzyme activity of obtainable is 0.8626 unit/ml while the spesific enzyme activity produced is 1.308 unit/mg. Then, 16S rRNA gene amplificatiom and DNA sequencing has been done. The results of study showed that the bacteria species contained from M4 bacteria lactic acid (LAB) isolate is Weisella cibiria strain II-I-59. Weisella cibiria strain II-I-59 is one of bacteria could be utilized in the digestive tract.
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Lactic acid bacteria found in fermented fish in Thailand.
Tanasupawat, Somboon; Okada, Sanae; Komagata, Kazuo
1998-06-01
Forty-seven strains of homofermentative rod-shaped and 5 heterofermentative sphere-shaped lactic acid bacteria were isolated from 4 kinds of fermented fish (pla-ra, pla-chom, kung-chom, and hoi-dong) in Thailand. These bacteria were separated into four groups by phenotypic and chemotaxonomic characteristics, including fluorometric DNA-DNA hybridization. Five strains (Group I) contained meso-diaminopimelic acid in the cell wall. Four strains were identified as Lactobacillus pentosus, and one strain was L. plantarum. Tested strains of this group produced DL-lactic acid. The rest of the rod-shaped bacteria, 23 strains (Group II) and 19 strains (Group III), lacked meso-diaminopimelic acid in the cell wall and were identified as L. farciminis and Lactobacillus species, respectively. The tested strains of these groups produced L-lactic acid. The amount of cellular fatty acids of C16:0 and C18:1, and the DNA base compositions were significant for differentiating the strains in Groups II and III. Five strains of cocci in chains (Group IV) produced gas from glucose. The tested strains of this group produced d-lactic acid. They were identified as a Leuconostoc species. The distribution of these bacteria in fermented fish in Thailand is discussed.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Xie, Gary; Dalin, Eileen; Tice, Hope
Bacillus coagulans is a ubiquitous soil bacterium that grows at 50-55 C and pH 5.0 and fer-ments various sugars that constitute plant biomass to L (+)-lactic acid. The ability of this sporogenic lactic acid bacterium to grow at 50-55 C and pH 5.0 makes this organism an attractive microbial biocatalyst for production of optically pure lactic acid at industrial scale not only from glucose derived from cellulose but also from xylose, a major constituent of hemi-cellulose. This bacterium is also considered as a potential probiotic. Complete genome squence of a representative strain, B. coagulans strain 36D1, is presented and discussed.
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NASA Astrophysics Data System (ADS)
Zhou, Xiuhong; Ge, Chunmei; Yao, Jianming; Pan, Renrui; Yu, Zengliang
2005-10-01
In order to obtain an industrial strain with a higher L(+)-lactic acid yield, the strain Rhizopus oryzae RF3608 was mutated by means of nitrogen ion beam implantation and the mutant strain RLC41-6 was isolated. Under optimal conditions the yield of L(+)-lactic acid produced in a shake-flask reached 133 g/L-137 g/L after 36 h cultivation, indicating that the conversion rate based on glucose was as high as 88%-91% and the productivity was 3.75 g/L.h. It was almost a 115% increase in lactic acid production compared with the original strain RF3608.
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Choi, Suk-Ho
2016-01-01
Airag, alcoholic sour-tasting beverage, has been traditionally prepared by Mongolian nomads who naturally ferment fresh mares' milk. Biochemical and microbiological compositions of airag samples collected in Ulaanbaatar, Mongolia and physiological characteristics of isolated lactic acid bacteria were investigated. Protein composition and biochemical composition were determined using sodium dodecyl sulfate-gel electrophoresis and high performance liquid chromatography, respectively. Lactic acid bacteria were identified based on nucleotide sequence of 16S rRNA gene. Carbohydrate fermentation, acid survival, bile resistance and acid production in skim milk culture were determined. Equine whey proteins were present in airag samples more than caseins. The airag samples contained 0.10-3.36 % lactose, 1.44-2.33 % ethyl alcohol, 1.08-1.62 % lactic acid and 0.12-0.22 % acetic acid. Lactobacillus (L.) helveticus were major lactic acid bacteria consisting of 9 isolates among total 18 isolates of lactic acid bacteria. L. helveticus survived strongly in PBS, pH 3.0 but did not grow in MRS broth containing 0.1 % oxgall. A couple of L. helveticus isolates lowered pH of skim milk culture to less than 4.0 and produced acid up to more than 1.0 %. Highly variable biochemical compositions of the airag samples indicated inconsistent quality due to natural fermentation. Airag with low lactose content should be favorable for nutrition, considering that mares' milk with high lactose content has strong laxative effect. The isolates of L. helveticus which produced acid actively in skim milk culture might have a major role in production of airag.
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Production of lactic acid from hemicellulose extracts by Bacillus coagulans MXL-9.
Walton, Sara L; Bischoff, Kenneth M; van Heiningen, Adriaan R P; van Walsum, G Peter
2010-08-01
Bacillus coagulans MXL-9 was found capable of growing on pre-pulping hemicellulose extracts, utilizing all of the principle monosugars found in woody biomass. This organism is a moderate thermophile isolated from compost for its pentose-utilizing capabilities. It was found to have high tolerance for inhibitors such as acetic acid and sodium, which are present in pre-pulping hemicellulose extracts. Fermentation of 20 g/l xylose in the presence of 30 g/l acetic acid required a longer lag phase but overall lactic acid yield was not diminished. Similarly, fermentation of xylose in the presence of 20 g/l sodium increased the lag time but did not affect overall product yield, though 30 g/l sodium proved completely inhibitory. Fermentation of hot water-extracted Siberian larch containing 45 g/l total monosaccharides, mainly galactose and arabinose, produced 33 g/l lactic acid in 60 h and completely consumed all sugars. Small amounts of co-products were formed, including acetic acid, formic acid, and ethanol. Hemicellulose extract formed during autohydrolysis of mixed hardwoods contained mainly xylose and was converted into lactic acid with a 94% yield. Green liquor-extracted hardwood hemicellulose containing 10 g/l acetic acid and 6 g/l sodium was also completely converted into lactic acid at a 72% yield. The Bacillus coagulans MXL-9 strain was found to be well suited to production of lactic acid from lignocellulosic biomass due to its compatibility with conditions favorable to industrial enzymes and its ability to withstand inhibitors while rapidly consuming all pentose and hexose sugars of interest at high product yields.
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Bai, Zhongzhong; Gao, Zhen; He, Bingfang; Wu, Bin
2015-10-01
The impact of lignocellulose-derived inhibitors on the cell growth and D-lactic production of Sporolactobacillus inulinus YBS1-5 was investigated. At high concentrations, both furans and phenolics, such as furfural, HMF, syringaldehyde and vanillin, affected cell growth and D-lactic acid production and syringaldehyde exhibited the highest. Further experiments showed that only vanillin caused cellular membrane damage. Based on the Biolog approach, in vivo studies on intact S. inulinus cells indicated that phenolics had a stronger inhibitory effect than furan derivatives on the metabolic activity of the concerned substrates related with the key enzymes of D-lactic acid fermentation. The direct in vitro inhibitory effect of the model compounds on the four key enzymes displayed similar patterns. Syringaldehyde was the strongest inhibitor. In general, comparison with published results for other microorganisms indicated that strain YBS1-5 was a robust microorganism against inhibitors of lignocellulose hydrolysate. Notably, in concentrated corn stover hydrolysate, S. inulinus YBS1-5 produced 70.7 g/L D-lactic acid, which was 87.7 % of the yield from the control experiment. However, the fermentation time was prolonged 36 h. In order to improve fermentation rate, a detoxification technology or more robust mutant to phenolics especially syringaldehyde should be developed.
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Diversity of predominant lactic acid bacteria associated with cocoa fermentation in Nigeria.
Kostinek, Melanie; Ban-Koffi, Louis; Ottah-Atikpo, Margaret; Teniola, David; Schillinger, Ulrich; Holzapfel, Wilhelm H; Franz, Charles M A P
2008-04-01
The fermentation of cocoa relies on a complex succession of bacteria and filamentous fungi, all of which can have an impact on cocoa flavor. So far, few investigations have focused on the diversity of lactic acid bacteria involved in cocoa fermentation, and many earlier investigations did not rely on polyphasic taxonomical approaches, which take both phenotypic and genotypic characterization techniques into account. In our study, we characterized predominant lactic acid bacteria from cocoa fermentations in Nigeria, using a combination of phenotypic tests, repetitive extragenic palindromic PCR, and sequencing of the 16S rRNA gene of representative strains for accurate species identification. Thus, of a total of 193 lactic acid bacteria (LAB) strains isolated from common media used to cultivate LAB, 40 (20.7%) were heterofermentative and consisted of either L. brevis or L. fermentum strains. The majority of the isolates were homofermentative rods (110 strains; 57% of isolates) which were characterized as L. plantarum strains. The homofermentative cocci consisted predominantly of 35 (18.1% of isolates) Pediococcus acidilactici strains. Thus, the LAB populations derived from these media in this study were accurately described. This can contribute to the further assessment of the effect of common LAB strains on the flavor characteristics of fermenting cocoa in further studies.
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Hyun, M Y; Lee, Y; No, Y A; Yoo, K H; Kim, M N; Hong, C K; Chang, S E; Won, C H; Kim, B J
2015-03-01
Hyaluronic acid (HA) fillers and poly-L-lactic acid (PLA) fillers are frequently used to correct facial wrinkles. To compare the efficacy and safety of a novel injectable poly-L-lactic acid (PLA) filler and a well-studied biphasic HA filler for the treatment of moderate to severe nasolabial folds. In this multicentre, randomized, evaluator-blinded, comparative study, subjects were randomized for injections with PLA or HA into both nasolabial folds. Efficacy was determined by calculating the change in Wrinkle Severity Rating Scale (WSRS) relative to baseline. Local safety was assessed by reported adverse events. At week 24, mean improvement in WSRS from baseline was 2.09 ± 0.68 for the PLA side and 1.54 ± 0.65 for the HA side. Both injections were well tolerated, and the adverse reactions were mild and transient in most cases. PLA provides noninferior efficacy compared with HA 6 months after being used to treat moderate to severe nasolabial folds. © 2014 British Association of Dermatologists.
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Detoxification of Sap from Felled Oil Palm Trunks for the Efficient Production of Lactic Acid.
Kunasundari, Balakrishnan; Arai, Takamitsu; Sudesh, Kumar; Hashim, Rokiah; Sulaiman, Othman; Stalin, Natra Joseph; Kosugi, Akihiko
2017-09-01
The availability of fermentable sugars in high concentrations in the sap of felled oil palm trunks and the thermophilic nature of the recently isolated Bacillus coagulans strain 191 were exploited for lactic acid production under non-sterile conditions. Screening indicated that strain 191 was active toward most sugars including sucrose, which is a major component of sap. Strain 191 catalyzed a moderate conversion of sap sugars to lactic acid (53%) with a productivity of 1.56 g/L/h. Pretreatment of oil palm sap (OPS) using alkaline precipitation improved the sugar fermentability, providing a lactic acid yield of 92% and productivity of 2.64 g/L/h. To better characterize potential inhibitors in the sap, phenolic, organic, and mineral compounds were analyzed using non-treated sap and saps treated with activated charcoal and alkaline precipitation. Phthalic acid, 3,4-dimethoxybenzoic acid, aconitic acid, syringic acid, and ferulic acid were reduced in the sap after treatment. High concentrations of Mg, P, K, and Ca were also precipitated by the alkaline treatment. These results suggest that elimination of excess phenolic and mineral compounds in OPS can improve the fermentation yield. OPS, a non-food resource that is readily available in bulk quantities from plantation sites, is a promising source for lactic acid production.
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Synthesis and Hydrolytic Degradation of Substituted Poly(DL-Lactic Acid)s
Tsuji, Hideto; Eto, Takehiko; Sakamoto, Yuzuru
2011-01-01
Non-substituted racemic poly(DL-lactic acid) (PLA) and substituted racemic poly(DL-lactic acid)s or poly(DL-2-hydroxyalkanoic acid)s with different side-chain lengths, i.e., poly(DL-2-hydroxybutanoic acid) (PBA), poly(DL-2-hydroxyhexanoic acid) (PHA), and poly(DL-2-hydroxydecanoic acid) (PDA) were synthesized by acid-catalyzed polycondensation of DL-lactic acid (LA), DL-2-hydroxybutanoic acid (BA), DL-2-hydroxyhexanoic acid (HA), and DL-2-hydroxydecanoic acid (DA), respectively. The hydrolytic degradation behavior was investigated in phosphate-buffered solution at 80 and 37 °C by gravimetry and gel permeation chromatography. It was found that the reactivity of monomers during polycondensation as monitored by the degree of polymerization (DP) decreased in the following order: LA > DA > BA > HA. The hydrolytic degradation rate traced by DP and weight loss at 80 °C decreased in the following order: PLA > PDA > PHA > PBA and that monitored by DP at 37 °C decreased in the following order: PLA > PDA > PBA > PHA. LA and PLA had the highest reactivity during polymerization and hydrolytic degradation rate, respectively, and were followed by DA and PDA. BA, HA, PBA, and PHA had the lowest reactivity during polymerization and hydrolytic degradation rate. The findings of the present study strongly suggest that inter-chain interactions play a major role in the reactivity of non-substituted and substituted LA monomers and degradation rate of the non-substituted and substituted PLA, along with steric hindrance of the side chains as can be expected. PMID:28824149
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Acid and bile tolerance of spore-forming lactic acid bacteria.
Hyronimus, B; Le Marrec, C; Sassi, A H; Deschamps, A
2000-11-01
Criteria for screening probiotics such as bile tolerance and resistance to acids were studied with 13 spore-forming lactic acid producing bacteria. Different strains of Sporolactobacillus, Bacillus laevolacticus, Bacillus racemilacticus and Bacillus coagulans grown in MRS broth were subjected to low pH conditions (2, 2.5 and 3) and increasing bile concentrations. Among these microorganisms, Bacillus laevolacticus DSM 6475 and all Sporolactobacillus strains tested except Sporolactobacillus racemicus IAM 12395, were resistant to pH 3. Only Bacillus racemilacticus and Bacillus coagulans strains were tolerant to bile concentrations over 0.3% (w/v).
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Vázquez, J A; González, M P; Murado, M A
2006-03-01
Lactic acid bacteria, the object of current interest as bacteriocin producers, are microorganisms with complex requirements for peptidic sources, making them appropriate indicators for testing the suitability of formulations based on proteinaceous wastes for use as microbiological media. Different peptones obtained from visceral and fish muscle residues promoted growth of lactic acid bacteria when applied individually or in combination. Kinetic parameters and bacteriocin production were similar and, in some cases (pediocin), far superior (>500%) to those obtained with bactopeptones and commercial media specifically recommended for lactic acid bacteria growth. Visceral residues, especially when subjected to a brief process of autohydrolysis at 20 degrees C, were more efficient for bacterial growth than muscle, even when muscle was treated with pepsin.
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Glucose and D-Allulose contained medium to support the growth of lactic acid bacteria
NASA Astrophysics Data System (ADS)
Al-Baarri, A. N.; Legowo, A. M.; Pramono, Y. B.; Sari, D. I.; Pangestika, W.
2018-01-01
Monosaccharide has been known as support agent for the growth of lactic acid bacteria. However the combination among monosaccharides for supporting the living of bacteria has not been understood well. This research was done for analyzing the combination glucose and D-allulose for the growth of Lactobacillus acidophilus and Streptococcus thermophillus. The NaCl medium containing glucose and D-allulose was used to analyse the growth of bacteria. The study showed that glucose and D-allulose have been detected as supportive agent to L. acidophilus and S. thermophillus specifically. As conclusion, glucose and D-allulose supported the growth of lactic acid bacteria equally. This finding might provide the beneficial information for industry to utilize D-allulose as well as glucose.
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Broadbent, J R; Oberg, T S; Hughes, J E; Ward, R E; Brighton, C; Welker, D L; Steele, J L
2014-03-01
Lactic acid is an important industrial chemical commonly produced through microbial fermentation. The efficiency of acid extraction is increased at or below the acid's pKa (pH 3.86), so there is interest in factors that allow for a reduced fermentation pH. We explored the role of cyclopropane synthase (Cfa) and polysorbate (Tween) 80 on acid production and membrane lipid composition in Lactobacillus casei ATCC 334 at low pH. Cells from wild-type and an ATCC 334 cfa knockout mutant were incubated in APT broth medium containing 3 % glucose plus 0.02 or 0.2 % Tween 80. The cultures were allowed to acidify the medium until it reached a target pH (4.5, 4.0, or 3.8), and then the pH was maintained by automatic addition of NH₄OH. Cells were collected at the midpoint of the fermentation for membrane lipid analysis, and media samples were analyzed for lactic and acetic acids when acid production had ceased. There were no significant differences in the quantity of lactic acid produced at different pH values by wild-type or mutant cells grown in APT, but the rate of acid production was reduced as pH declined. APT supplementation with 0.2 % Tween 80 significantly increased the amount of lactic acid produced by wild-type cells at pH 3.8, and the rate of acid production was modestly improved. This effect was not observed with the cfa mutant, which indicated Cfa activity and Tween 80 supplementation were each involved in the significant increase in lactic acid yield observed with wild-type L. casei at pH 3.8.
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Leguminose green juice as an efficient nutrient for l(+)-lactic acid production.
Dietz, Donna; Schneider, Roland; Papendiek, Franka; Venus, Joachim
2016-10-20
Lactic acid is one of the most important building blocks for the production of bioplastic. Many investigations have been conducted to reduce the lactic acid production costs. In this work, the focus was put on the application of legume pressed juice or green juice as nutrient source. The pressed juice was utilized directly without prior pre-treatment and sterilization. Using two different alfalfa green juices and a clover green juice from two different harvest years as sole nutrients, non-sterile fermentations were performed at 52°C and pH 6.0 with a thermotolerant strain Bacillus coagulans AT107. The results showed that alfalfa green juices generally were more suitable for high lactic acid production than clover green juices, presumably due to the higher nitrogen content. A final titer of 98.8g/L after 30h with l(+)-lactic acid purity of >99% was obtained. Copyright © 2016 Elsevier B.V. All rights reserved.
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Wang, Yongze; Tian, Tian; Zhao, Jinfang; Wang, Jinhua; Yan, Tao; Xu, Liyuan; Liu, Zao; Garza, Erin; Iverson, Andrew; Manow, Ryan; Finan, Chris; Zhou, Shengde
2012-11-01
Escherichia coli W, a sucrose-positive strain, was engineered for the homofermentative production of D-lactic acid through chromosomal deletion of the competing fermentative pathway genes (adhE, frdABCD, pta, pflB, aldA) and the repressor gene (cscR) of the sucrose operon, and metabolic evolution for improved anaerobic cell growth. The resulting strain, HBUT-D, efficiently fermented 100 g sucrose l(-1) into 85 g D-lactic acid l(-1) in 72-84 h in mineral salts medium with a volumetric productivity of ~1 g l(-1) h(-1), a product yield of 85 % and D-lactic acid optical purity of 98.3 %, and with a minor by-product of 4 g acetate l(-1). HBUT-D thus has great potential for production of D-lactic acid using an inexpensive substrate, such as sugar cane and/or beet molasses, which are primarily composed of sucrose.
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D-lactic acidosis: an underrecognized complication of short bowel syndrome.
Kowlgi, N Gurukripa; Chhabra, Lovely
2015-01-01
D-lactic acidosis or D-lactate encephalopathy is a rare condition that occurs primarily in individuals who have a history of short bowel syndrome. The unabsorbed carbohydrates act as a substrate for colonic bacteria to form D-lactic acid among other organic acids. The acidic pH generated as a result of D-lactate production further propagates production of D-lactic acid, hence giving rise to a vicious cycle. D-lactic acid accumulation in the blood can cause neurologic symptoms such as delirium, ataxia, and slurred speech. Diagnosis is made by a combination of clinical and laboratory data including special assays for D-lactate. Treatment includes correcting the acidosis and decreasing substrate for D-lactate such as carbohydrates in meals. In addition, antibiotics can be used to clear colonic flora. Although newer techniques for diagnosis and treatment are being developed, clinical diagnosis still holds paramount importance, as there can be many confounders in the diagnosis as will be discussed subsequently.
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D-Lactic Acidosis: An Underrecognized Complication of Short Bowel Syndrome
Kowlgi, N. Gurukripa; Chhabra, Lovely
2015-01-01
D-lactic acidosis or D-lactate encephalopathy is a rare condition that occurs primarily in individuals who have a history of short bowel syndrome. The unabsorbed carbohydrates act as a substrate for colonic bacteria to form D-lactic acid among other organic acids. The acidic pH generated as a result of D-lactate production further propagates production of D-lactic acid, hence giving rise to a vicious cycle. D-lactic acid accumulation in the blood can cause neurologic symptoms such as delirium, ataxia, and slurred speech. Diagnosis is made by a combination of clinical and laboratory data including special assays for D-lactate. Treatment includes correcting the acidosis and decreasing substrate for D-lactate such as carbohydrates in meals. In addition, antibiotics can be used to clear colonic flora. Although newer techniques for diagnosis and treatment are being developed, clinical diagnosis still holds paramount importance, as there can be many confounders in the diagnosis as will be discussed subsequently. PMID:25977687
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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.
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Precision genome engineering in lactic acid bacteria
2014-01-01
Innovative new genome engineering technologies for manipulating chromosomes have appeared in the last decade. One of these technologies, recombination mediated genetic engineering (recombineering) allows for precision DNA engineering of chromosomes and plasmids in Escherichia coli. Single-stranded DNA recombineering (SSDR) allows for the generation of subtle mutations without the need for selection and without leaving behind any foreign DNA. In this review we discuss the application of SSDR technology in lactic acid bacteria, with an emphasis on key factors that were critical to move this technology from E. coli into Lactobacillus reuteri and Lactococcus lactis. We also provide a blueprint for how to proceed if one is attempting to establish SSDR technology in a lactic acid bacterium. The emergence of CRISPR-Cas technology in genome engineering and its potential application to enhancing SSDR in lactic acid bacteria is discussed. The ability to perform precision genome engineering in medically and industrially important lactic acid bacteria will allow for the genetic improvement of strains without compromising safety. PMID:25185700
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Stillage reflux in food waste ethanol fermentation and its by-product accumulation.
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.
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Transient MutS-Based Hypermutation System for Adaptive Evolution of Lactobacillus casei to Low pH.
Overbeck, Tom J; Welker, Dennis L; Hughes, Joanne E; Steele, James L; Broadbent, Jeff R
2017-10-15
This study explored transient inactivation of the gene encoding the DNA mismatch repair enzyme MutS as a tool for adaptive evolution of Lactobacillus casei MutS deletion derivatives of L. casei 12A and ATCC 334 were constructed and subjected to a 100-day adaptive evolution process to increase lactic acid resistance at low pH. Wild-type parental strains were also subjected to this treatment. At the end of the process, the Δ mutS lesion was repaired in representative L. casei 12A and ATCC 334 Δ mutS mutant isolates. Growth studies in broth at pH 4.0 (titrated with lactic acid) showed that all four adapted strains grew more rapidly, to higher cell densities, and produced significantly more lactic acid than untreated wild-type cells. However, the adapted Δ mutS derivative mutants showed the greatest increases in growth and lactic acid production. Further characterization of the L. casei 12A-adapted Δ mutS derivative revealed that it had a significantly smaller cell volume, a rougher cell surface, and significantly better survival at pH 2.5 than parental L. casei 12A. Genome sequence analysis confirmed that transient mutS inactivation decreased DNA replication fidelity in both L. casei strains, and it identified genetic changes that might contribute to the lactic acid-resistant phenotypes of adapted cells. Targeted inactivation of three genes that had acquired nonsense mutations in the adapted L. casei 12A Δ mutS mutant derivative showed that NADH dehydrogenase ( ndh ), phosphate transport ATP-binding protein PstB ( pstB ), and two-component signal transduction system (TCS) quorum-sensing histidine protein kinase ( hpk ) genes act in combination to increase lactic acid resistance in L. casei 12A. IMPORTANCE Adaptive evolution has been applied to microorganisms to increase industrially desirable phenotypes, including acid resistance. We developed a method to increase the adaptability of Lactobacillus casei 12A and ATCC 334 through transient inactivation of the DNA mismatch repair enzyme MutS. Here, we show this method was effective in increasing the resistance of L. casei to lactic acid at low pH. Additionally, we identified three genes that contribute to increased acid resistance in L. casei 12A. These results provide valuable insight on methods to enhance an organism's fitness to complex phenotypes through adaptive evolution and targeted gene inactivation. Copyright © 2017 American Society for Microbiology.
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Transient MutS-Based Hypermutation System for Adaptive Evolution of Lactobacillus casei to Low pH
Overbeck, Tom J.; Welker, Dennis L.; Hughes, Joanne E.; Steele, James L.
2017-01-01
ABSTRACT This study explored transient inactivation of the gene encoding the DNA mismatch repair enzyme MutS as a tool for adaptive evolution of Lactobacillus casei. MutS deletion derivatives of L. casei 12A and ATCC 334 were constructed and subjected to a 100-day adaptive evolution process to increase lactic acid resistance at low pH. Wild-type parental strains were also subjected to this treatment. At the end of the process, the ΔmutS lesion was repaired in representative L. casei 12A and ATCC 334 ΔmutS mutant isolates. Growth studies in broth at pH 4.0 (titrated with lactic acid) showed that all four adapted strains grew more rapidly, to higher cell densities, and produced significantly more lactic acid than untreated wild-type cells. However, the adapted ΔmutS derivative mutants showed the greatest increases in growth and lactic acid production. Further characterization of the L. casei 12A-adapted ΔmutS derivative revealed that it had a significantly smaller cell volume, a rougher cell surface, and significantly better survival at pH 2.5 than parental L. casei 12A. Genome sequence analysis confirmed that transient mutS inactivation decreased DNA replication fidelity in both L. casei strains, and it identified genetic changes that might contribute to the lactic acid-resistant phenotypes of adapted cells. Targeted inactivation of three genes that had acquired nonsense mutations in the adapted L. casei 12A ΔmutS mutant derivative showed that NADH dehydrogenase (ndh), phosphate transport ATP-binding protein PstB (pstB), and two-component signal transduction system (TCS) quorum-sensing histidine protein kinase (hpk) genes act in combination to increase lactic acid resistance in L. casei 12A. IMPORTANCE Adaptive evolution has been applied to microorganisms to increase industrially desirable phenotypes, including acid resistance. We developed a method to increase the adaptability of Lactobacillus casei 12A and ATCC 334 through transient inactivation of the DNA mismatch repair enzyme MutS. Here, we show this method was effective in increasing the resistance of L. casei to lactic acid at low pH. Additionally, we identified three genes that contribute to increased acid resistance in L. casei 12A. These results provide valuable insight on methods to enhance an organism's fitness to complex phenotypes through adaptive evolution and targeted gene inactivation. PMID:28802267
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Anderson, Catherine; Malambo, Dennis Hanjalika; Perez, Maria Eliette Gonzalez; Nobela, Happiness Ngwanamoseka; de Pooter, Lobke; Spit, Jan; Hooijmans, Christine Maria; de Vossenberg, Jack van; Greya, Wilson; Thole, Bernard; van Lier, Jules B; Brdjanovic, Damir
2015-10-29
In this research, three faecal sludge sanitizing methods-lactic acid fermentation, urea treatment and lime treatment-were studied for application in emergency situations. These methods were investigated by undertaking small scale field trials with pit latrine sludge in Blantyre, Malawi. Hydrated lime was able to reduce the E. coli count in the sludge to below the detectable limit within 1 h applying a pH > 11 (using a dosage from 7% to 17% w/w, depending faecal sludge alkalinity), urea treatment required about 4 days using 2.5% wet weight urea addition, and lactic acid fermentation needed approximately 1 week after being dosed with 10% wet weight molasses (2 g (glucose/fructose)/kg) and 10% wet weight pre-culture (99.8% pasteurised whole milk and 0.02% fermented milk drink containing Lactobacillus casei Shirota). Based on Malawian prices, the cost of sanitizing 1 m³ of faecal sludge was estimated to be €32 for lactic acid fermentation, €20 for urea treatment and €12 for hydrated lime treatment.
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NASA Astrophysics Data System (ADS)
Ge, Chunmei; Yang, Yingge; Fan, Yonghong; Li, Wen; Pan, Renrui; Zheng, Zhiming; Yu, Zengliang
2008-02-01
The wild type strain Rhizopus oryzae PW352 was mutated by means of nitrogen ion implantation (15 keV, 7.8 × 1014 ~ 2.08 × 1015 ions/cm2) to find an industrial strain with a higher L(+)-lactic acid yield, and two mutants RE3303 and RF9052 were isolated. In order to discuss the mechanism primarily, Lactate Dehydrogenase of Rhizopus oryzae was studied. While the two mutants produced L(+)-lactic acid by 75% more than the wild strain did, their specific activity of Lactate Dehydrogenase was found to be higher than that in the wild strain. The optimum temperature of Lactate Dehydrogenase in Rhizopus oryzae RF9052 was higher. Compared to the wild strain, the Michaelis constant (Km) value of Lactate Dehydrogenase in the mutants was changed. All these changes show that L(+)-lactic acid production has a correlation with the specific activity of Lactate Dehydrogenase. The low-energy ions, implanted into the strain, may improve the specific activity of Lactate Dehydrogenase by influencing its gene structure and protein structure.
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Anderson, Catherine; Malambo, Dennis Hanjalika; Gonzalez Perez, Maria Eliette; Nobela, Happiness Ngwanamoseka; de Pooter, Lobke; Spit, Jan; Hooijmans, Christine Maria; van de Vossenberg, Jack; Greya, Wilson; Thole, Bernard; van Lier, Jules B.; Brdjanovic, Damir
2015-01-01
In this research, three faecal sludge sanitizing methods—lactic acid fermentation, urea treatment and lime treatment—were studied for application in emergency situations. These methods were investigated by undertaking small scale field trials with pit latrine sludge in Blantyre, Malawi. Hydrated lime was able to reduce the E. coli count in the sludge to below the detectable limit within 1 h applying a pH > 11 (using a dosage from 7% to 17% w/w, depending faecal sludge alkalinity), urea treatment required about 4 days using 2.5% wet weight urea addition, and lactic acid fermentation needed approximately 1 week after being dosed with 10% wet weight molasses (2 g (glucose/fructose)/kg) and 10% wet weight pre-culture (99.8% pasteurised whole milk and 0.02% fermented milk drink containing Lactobacillus casei Shirota). Based on Malawian prices, the cost of sanitizing 1 m3 of faecal sludge was estimated to be €32 for lactic acid fermentation, €20 for urea treatment and €12 for hydrated lime treatment. PMID:26528995
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Minervini, Fabio; Celano, Giuseppe; Lattanzi, Anna; Tedone, Luigi; De Mastro, Giuseppe; Gobbetti, Marco; De Angelis, Maria
2015-10-01
This study aimed at assessing the dynamics of lactic acid bacteria and other Firmicutes associated with durum wheat organs and processed products. 16S rRNA gene-based high-throughput sequencing showed that Lactobacillus, Streptococcus, Enterococcus, and Lactococcus were the main epiphytic and endophytic genera among lactic acid bacteria. Bacillus, Exiguobacterium, Paenibacillus, and Staphylococcus completed the picture of the core genus microbiome. The relative abundance of each lactic acid bacterium genus was affected by cultivars, phenological stages, other Firmicutes genera, environmental temperature, and water activity (aw) of plant organs. Lactobacilli, showing the highest sensitivity to aw, markedly decreased during milk development (Odisseo) and physiological maturity (Saragolla). At these stages, Lactobacillus was mainly replaced by Streptococcus, Lactococcus, and Enterococcus. However, a key sourdough species, Lactobacillus plantarum, was associated with plant organs during the life cycle of Odisseo and Saragolla wheat. The composition of the sourdough microbiota and the overall quality of leavened baked goods are also determined throughout the phenological stages of wheat cultivation, with variations depending on environmental and agronomic factors. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
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Production of D-lactic acid from sugarcane bagasse using steam-explosion
NASA Astrophysics Data System (ADS)
Sasaki, Chizuru; Okumura, Ryosuke; Asakawa, Ai; Asada, Chikako; Nakamura, Yoshitoshi
2012-03-01
This study investigated the production of D-lactic acid from unutilized sugarcane bagasse using steam explosion pretreatment. The optimal steam pressure for a steaming time of 5 min was determined. By enzymatic saccharification using Meicellase, the highest recovery of glucose from raw bagasse, 73.7%, was obtained at a steam pressure of 20 atm. For residue washed with water after steam explosion, the glucose recovery increased up to 94.9% at a steam pressure of 20 atm. These results showed that washing with water is effective in removing enzymatic reaction inhibitors. After steam pretreatment (steam pressure of 20 atm), D-lactic acid was produced by Lactobacillus delbrueckii NBRC 3534 from the enzymatic hydrolyzate of steam-exploded bagasse and washed residue. The conversion rate of D-lactic acid obtained from the initial glucose concentration was 66.6% for the hydrolyzate derived from steam-exploded bagasse and 90.0% for that derived from the washed residue after steam explosion. These results also demonstrated that the hydrolyzate of steam-exploded bagasse (without washing with water) contains fermentation inhibitors and washing with water can remove them.
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Piezoelectric antibacterial fabric comprised of poly(l-lactic acid) yarn
NASA Astrophysics Data System (ADS)
Ando, Masamichi; Takeshima, Satoshi; Ishiura, Yutaka; Ando, Kanako; Onishi, Osamu
2017-10-01
A lactic acid monomer has an asymmetric carbon in the molecule, so there are optical isomer l- and d-type. The most widely used poly(lactic acid) (PLA) for commercial applications is poly(l-lactic acid) (PLLA). PLLA is the polymerization product of l-lactide. Certain treatments of PLLA can yield a film that exhibits shear piezoelectricity. Thus, piezoelectric PLLA fiber can be generated by micro slitting piezoelectric PLLA films or by a melt spinning method. We prepared left-handed helical multi fiber yarn (S-yarn) and right-handed helical yarn (Z-yarn) using piezoelectric PLLA fiber. PLLA exhibited shear mode piezoelectricity, causing the electric polarity of the yarn surface to be reversed on the S-yarn and Z-yarn when tension was applied. An SZ-yarn was produced by combining the S-yarn and Z-yarn, and fabric was prepared using the SZ-yarn. This study demonstrated that the fabric has a strong antibacterial effect, which is thought to be due to the strong electric field between the yarns. The field is generated by a piezoelectric effect when the fabric was extended and contracted.
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Minervini, Fabio; Celano, Giuseppe; Lattanzi, Anna; Tedone, Luigi; De Mastro, Giuseppe; De Angelis, Maria
2015-01-01
This study aimed at assessing the dynamics of lactic acid bacteria and other Firmicutes associated with durum wheat organs and processed products. 16S rRNA gene-based high-throughput sequencing showed that Lactobacillus, Streptococcus, Enterococcus, and Lactococcus were the main epiphytic and endophytic genera among lactic acid bacteria. Bacillus, Exiguobacterium, Paenibacillus, and Staphylococcus completed the picture of the core genus microbiome. The relative abundance of each lactic acid bacterium genus was affected by cultivars, phenological stages, other Firmicutes genera, environmental temperature, and water activity (aw) of plant organs. Lactobacilli, showing the highest sensitivity to aw, markedly decreased during milk development (Odisseo) and physiological maturity (Saragolla). At these stages, Lactobacillus was mainly replaced by Streptococcus, Lactococcus, and Enterococcus. However, a key sourdough species, Lactobacillus plantarum, was associated with plant organs during the life cycle of Odisseo and Saragolla wheat. The composition of the sourdough microbiota and the overall quality of leavened baked goods are also determined throughout the phenological stages of wheat cultivation, with variations depending on environmental and agronomic factors. PMID:26187970
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NASA Astrophysics Data System (ADS)
Quynh, Tran Minh; Mai, Hoang Hoa; Lan, Pham Ngoc
2013-02-01
Poly(L-lactic acid)s (PLLAx) were synthesized from L-lactic acid by polycondensation. Different stereocomplexes were also obtained with equimolar mixtures of synthesized PLLAx and a commercial PDLA. The stereocomplexes were crosslinked with triallyl isocyanurate (TAIC) by gamma irradiation. Crosslinking density increased with radiation doses, the heavier the crosslinking network, the lower its swelling degree. The crosslinking structures were introduced in the stereocomplexes inhibiting the mobility for crystallization of PLLA molecules. Thermal and mechanical properties of PLA stereocomplexes were remarkably enhanced by radiation induced crosslinking. PLA stereocomplex does not seem to be degraded by PLLA degrading microorganisms existing in compost at room temperature, but the synthesized PLLA was significantly degraded.
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NASA Astrophysics Data System (ADS)
Nur Jannah, Siti; Rini Saraswati, Tyas; Handayani, Dwi; Pujiyanto, Sri
2018-05-01
Food borne disease results from ingestion of water and wide variety of food contaminated with pathogenic organisms. The main causes of food borne diseases are bacteria, such as Escherichia coli and Staphylococcus aureus. The objective of this study was to determine antimicrobial activity of lactic acid bacteria (LAB) isolated from local chicken gastrointestinal tract with an emphasis on their probiotic properties. The colonies of bacteria that producing clear zone on MRSA plus 0.5% CaCO3, Gram-positive and catalase-negative were isolated as lactic acid bacteria. Some of the strains (10 isolates) were tested for their ability to inhibit growth of Escherichia coli and Staphylococcus aureus, and for acid pH and bile salt tolerance. The results showed that the all selected isolates producing antimicrobial compounds inhibits the growth of Escherichia coli and Staphylococcus aureus, both in the supernatant and supernatant plus 2M NaOH, and still growing in medium condition with pH 2.0 and 0.1% bile salt. It revealing the potential use of the lactic acid bacteria from chicken gastrointestinal tract for probiotics in food.
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Yu, Bo; Su, Fei; Wang, Limin; Zhao, Bo; Qin, Jiayang; Ma, Cuiqing; Xu, Ping; Ma, Yanhe
2011-01-01
Lactobacillus rhamnosus is a type of probiotic bacteria with industrial potential for l-lactic acid production. We announce the draft genome sequence of L. rhamnosus CASL (2,855,156 bp with a G+C content of 46.6%), which is an efficient producer of l-lactic acid from cheap, nonfood substrate cassava with a high production titer. PMID:22123765
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Su, Fei; Yu, Bo; Sun, Jibin; Ou, Hong-Yu; Zhao, Bo; Wang, Limin; Qin, Jiayang; Tang, Hongzhi; Tao, Fei; Jarek, Michael; Scharfe, Maren; Ma, Cuiqing; Ma, Yanhe; Xu, Ping
2011-09-01
Bacillus coagulans 2-6 is an efficient producer of lactic acid. The genome of B. coagulans 2-6 has the smallest genome among the members of the genus Bacillus known to date. The frameshift mutation at the start of the d-lactate dehydrogenase sequence might be responsible for the production of high-optical-purity l-lactic acid.
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NASA Astrophysics Data System (ADS)
Noshiranzadeh, Nader; Heidari, Azam; Haghi, Fakhri; Bikas, Rahman; Lis, Tadeusz
2017-01-01
A series of novel chiral lactic-hydrazone derivatives were synthesized by condensation of (S)-lactic acid hydrazide with salicylaldehyde derivatives and characterized by elemental analysis and spectroscopic studies (FT-IR, 1H NMR and 13C NMR spectroscopy). The structure of one compound was determined by single crystal X-ray analysis. Antibacterial activity of the synthesized compounds was studied against Staphylococcus aureus, Streptococcus pneumonia, Escherichia coli and Pseudomonas aeruginosa as bacterial cultures by broth microdilution method. All of the synthesized compounds showed good antibacterial activity with MIC range of 64-512 μg/mL. Compounds (S,E)-2-hydroxy-N-(2-hydroxy-5-nitrobenzylidene)propanehydrazide (5) and (S,E)-2-hydroxy-N-((3-hydroxy-5-(hydroxymethyl)-2-methylpyridin-4-yl)propanehydrazide (7) were the most effective antibacterial derivatives against S. aureus and E. coli respectively with a MIC value of 64 μg/mL. Bacterial biofilm formation assay showed that these compounds significantly inhibited biofilm formation of P. aeruginosa. Also, in silico molecular docking studies were performed to show lipoteichoic acid synthase (LtaS) inhibitory effect of lactic hydrazone derivatives. The association between electronic and structural effects of some substituents on the benzylidene moiety and the biological activity of these chiral compounds were studied. Structural studies show that compound with higher hydrogen bonding interactions show higher antibacterial activity. The results show chiral hydrazone derivatives based on lactic acid hydrazide could be used as potential lead compounds for developing novel antibacterial agents.
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Maneeboon, Thanapoom; Vanichsriratana, Wirat; Pomchaitaward, Chaiyaporn; Kitpreechavanich, Vichien
2010-05-01
The influence of two key environmental factors, pH and oxygen transfer coefficient (k(L)a), was evaluated on the lactic acid production as the main answer and, on the size of cell pellets of the fungal strain Rhizopus oryzae KPS106, as second dependant answer by response surface methodology using a central composite design. The results of the analysis of variance and modeling demonstrated that pH and k(L)a had a significant effect on lactic acid production by this strain. However, no interaction was observed between these two experimental factors. pH and k(L)a had no significant influence on the pellet size. Optimal pH and k(L)a of the fermentation medium for lactic acid production from response surface analysis was 5.85 and of 3.6 h(-1), respectively. The predicted and experimental lactic acid maximal values were 75.4 and 72.0 g/l, respectively, with pellets of an average of 2.54 +/- 0.41 mm. Five repeated batches in series were conducted with a mean lactic acid production of 77.54 g/l. The productivity was increased from 0.75 in the first batch to 0.99 g/l h in the last fifth batch.
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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.
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Monmaturapoj, Naruporn; Srion, Autcharaporn; Chalermkarnon, Prasert; Buchatip, Suthawan; Petchsuk, Atitsa; Noppakunmongkolchai, Warobon; Mai-Ngam, Katanchalee
2017-08-01
A composite of 70/30 poly(lactic acid)/hydroxyapatite was systematically prepared using various amounts of glycidyl methacrylate as reactive compatibilizer or Joncryl ADR®-4368 containing nine glycidyl methacrylate functions as a chain extension/branching agent to improve the mechanical and biological properties for suitable usage as internal bone fixation devices. The effect of glycidyl methacrylate/Joncryl on mechanical properties of poly(lactic acid)/hydroxyapatite was investigated through flexural strength. Cell proliferation and differentiation of osteoblast-like MC3T3-E1 cells cultured on the composite samples were determined by Alamar Blue assay and alkaline phosphatase expression, respectively. Result shows that flexural strength tends to decrease, as glycidyl methacrylate content increases except for 1 wt.% glycidyl methacrylate. With an addition of dicumyl peroxide, the flexural strength shows an improvement than that of without dicumyl peroxide probably due to the chemical bonding of the hydroxyapatite and poly(lactic acid) as revealed by FTIR and NMR, whereas the composite with 5 wt.% Joncryl shows the best result, as the flexural strength increases getting close to pure poly(lactic acid). The significant morphology change could be seen in composite with Joncryl where the uniform agglomeration of hydroxyapatite particles oriented in poly(lactic acid) matrix. Addition of the epoxy functional compatibilizers at suitable percentages could also have benefits to cellular attachment, proliferation, differentiation and mineralization. So that, this poly(lactic acid)/hydroxyapatite composite could be a promising material to be used as internal bone fixation devices such as screws, pins and plates.
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Gefrom, A; Ott, E M; Hoedtke, S; Zeyner, A
2013-12-01
Ensiling legume grain may be an inexpensive and ecologically interesting method to produce a high-protein feed of local origin. The typically patchy maturation recommends harvesting and ensiling the seeds in moist condition. Developing a method for preserving legume grains harvested before maturation by lactic acid fermentation would have several advantages. Under laboratory conditions, crushed legume seeds of beans, peas and lupines with high moisture content of 35 % were ensiled with different additives (molasses and lactic acid bacteria). To characterize the final silages, contents of proximate nutrients and antinutritional factors (alkaloids, oligosaccharides, tannins) were analysed. The addition of lactic acid bacteria ensured a fast and pronounced lactic acid production and decreased contents of undesired fermentation products like ethanol. An additional use of molasses for ensilage did not provide a remarkable additional benefit. Excluding sugar and starch, the contents of proximate nutrients were not remarkably altered after ensiling. As an overall effect, lactic acid fermentation reduced tannins and oligosaccharides. It can be supposed that the oligosaccharides after breakdown of the complex molecules acted as a source of fermentable carbohydrates. A relevant reduction of alkaloids did not occur. The lactic acid fermentation of legume grains can be recommended as an appropriate method for conservation. With respect to the economic advantages and compared with methods of chemical preservation, the lactic acid fermentation of legume grains under anaerobic conditions is an environmentally compliant procedure and therefore also an option for organic farming. © 2012 Blackwell Verlag GmbH.
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Huang, Hanjing; Yang, Shang-Tian; Ramey, David E
2004-01-01
An energy-efficient hollow-fiber membrane extraction process was successfully developed to separate and recover lactic acid produced in fermentation. Although many fermentation processes have been developed for lactic acid production, an economical method for lactic acid recovery from the fermentation broth is still needed. Continuous extraction of lactic acid from a simulated aqueous stream was achieved by using Alamine 336 in 2-octanol contained in a hollow-fiber membrane extractor. In this process, the extractant was simultaneously regenerated by stripping with NaOH in a second membrane extractor, and the final product is a concentrated lactate salt solution. The extraction rate increased linearly with an increase in the Alamine 336 content in the solvent (from 5 to 40%). Increasing the concentration of the undissociated lactic acid in the feed solution by either increasing the lactate concentration (from 5 to 40 g/L) or decreasing the solution pH (from 5.0 to 4.0) also increased the extraction rate. Based on these observations, a reactive extraction model with a first-order reaction mechanism for both lactic acid and amine concentrations was proposed. The extraction rate also increased with an increase in the feed flow rate, but not the flow rates of solvent and the stripping solution, suggesting that the process was not limited by diffusion in the liquid films or membrane pores. A mathematical model considering both diffusion and chemical reaction in the extractor and back extractor was developed to simulate the process. The model fits the experimental data well and can be used in scale up design of the process.
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Characterization and application of lactic acid bacteria for tropical silage preparation.
Pholsen, Suradej; Khota, Waroon; Pang, Huili; Higgs, David; Cai, Yimin
2016-10-01
Strains TH 14, TH 21 and TH 64 were isolated from tropical silages, namely corn stover, sugar cane top and rice straw, respectively, prepared in Thailand. These strains were selected by low pH growth range and high lactic acid-producing ability, similar to some commercial inoculants. Based on the analysis of 16S ribosomal RNA gene sequence and DNA-DNA relatedness, strain TH 14 was identified as Lactobacillus casei, and strains TH 21 and TH 64 were identified as L. plantarum. Strains TH 14, TH 21, TH 64 and two commercial inoculants, CH (L. plantarum) and SN (L. rhamnosus), were used as additives to fresh and wilted purple Guinea and sorghum silages prepared using a small-scale fermentation method. The number of epiphytic lactic acid bacteria (LAB) in the forages before ensilage was relatively low but the numbers of coliform and aerobic bacteria were higher. Sorghum silages at 30 days of fermentation were all well preserved with low pH (3.56) and high lactic acid production (72.86 g/kg dry matter). Purple Guinea silage inoculated with LAB exhibited reduced count levels of aerobic and coliform bacteria, lower pH, butyric acid and ammonia nitrogen and increased lactic acid concentration, compared with the control. Strain TH 14 more effectively improved lactic acid production compared with inoculants and other strains. © 2016 Japanese Society of Animal Science. © 2016 Japanese Society of Animal Science.
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Bartkiene, Elena; Krungleviciute, Vita; Juodeikiene, Grazina; Vidmantiene, Daiva; Maknickiene, Zita
2015-04-01
The ability of bacteriocin-like inhibitory substance (BLIS)-producing lactic acid bacteria (LAB) to degrade biogenic amines as well as to produce L(+) and D(-)-lactic acid during solid state fermentation (SSF) of lupin and soya bean was investigated. In addition, the protein digestibility and formation of organic acids during SSF of legume were investigated. Protein digestibility of fermented lupin and soya bean was found higher on average by 18.3% and 15.9%, respectively, compared to untreated samples. Tested LAB produced mainly L-lactic acid in soya bean and lupin (D/L ratio 0.38-0.42 and 0.35-0.54, respectively), while spontaneous fermentation gave almost equal amounts of both lactic acid isomers (D/L ratio 0.82-0.98 and 0.92, respectively). Tested LAB strains were able to degrade phenylethylamine, spermine and spermidine, whereas they were able to produce putrescine, histamine and tyramine. SSF improved lupin and soya bean protein digestibility. BLIS-producing LAB in lupin and soya bean medium produced a mixture of D- and L-lactic acid with a major excess of the latter isomer. Most toxic histamine and tyramine in fermented lupin and soya bean were found at levels lower those causing adverse health effects. Selection of biogenic amines non-producing bacteria is essential in the food industry to avoid the risk of amine formation. © 2014 Society of Chemical Industry.
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Lactic acid fermentation of human urine to improve its fertilizing value and reduce odour emissions.
Andreev, N; Ronteltap, M; Boincean, B; Wernli, M; Zubcov, E; Bagrin, N; Borodin, N; Lens, P N L
2017-08-01
During storage of urine, urea is biologically decomposed to ammonia, which can be lost through volatilization and in turn causes significant unpleasant smell. In response, lactic acid fermentation of urine is a cost-effective technique to decrease nitrogen volatilization and reduce odour emissions. Fresh urine (pH = 5.2-5.3 and NH 4 + -N = 1.2-1.3 g L -1 ) was lacto-fermented for 36 days in closed glass jars with a lactic acid bacterial inoculum from sauerkraut juice and compared to untreated, stored urine. In the lacto-fermented urine, the pH was reduced to 3.8-4.7 and the ammonium content by 22-30%, while the pH of the untreated urine rose to 6.1 and its ammonium content increased by 32% due to urea hydrolysis. The concentration of lactic acid bacteria in lacto-fermented urine was 7.3 CFU ml -1 , suggesting that urine is a suitable growth medium for lactic acid bacteria. The odour of the stored urine was subjectively perceived by four people to be twice as strong as that of lacto-fermented samples. Lacto-fermented urine induced increased radish germination compared to stored urine (74-86% versus 2-31%). Adding a lactic acid bacterial inoculum to one week old urine in the storage tanks in a urine-diverting dry toilet reduced the pH from 8.9 to 7.7 after one month, while the ammonium content increased by 35%, probably due to the high initial pH of the urine. Given that the hydrolyzed stale urine has a high buffering capacity, the lactic acid bacterial inoculum should be added to the urine storage tank of a UDDT before urine starts to accumulate there to increase the efficiency of the lactic acid fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.
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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.
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21 CFR 133.129 - Dry curd cottage cheese.
Code of Federal Regulations, 2014 CFR
2014-04-01
... of the following methods is employed: (i) Harmless lactic-acid-producing bacteria, with or without... pressed, chilled, worked, seasoned with salt; or (ii) Food grade phosphoric acid, lactic acid, citric acid..., seasoned with salt. (iii) Food grade acids as provided in paragraph (b)(1)(ii) of this section, D-Glucono...
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21 CFR 133.129 - Dry curd cottage cheese.
Code of Federal Regulations, 2012 CFR
2012-04-01
... of the following methods is employed: (i) Harmless lactic-acid-producing bacteria, with or without... pressed, chilled, worked, seasoned with salt; or (ii) Food grade phosphoric acid, lactic acid, citric acid..., seasoned with salt. (iii) Food grade acids as provided in paragraph (b)(1)(ii) of this section, D-Glucono...
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21 CFR 133.129 - Dry curd cottage cheese.
Code of Federal Regulations, 2013 CFR
2013-04-01
... of the following methods is employed: (i) Harmless lactic-acid-producing bacteria, with or without... pressed, chilled, worked, seasoned with salt; or (ii) Food grade phosphoric acid, lactic acid, citric acid..., seasoned with salt. (iii) Food grade acids as provided in paragraph (b)(1)(ii) of this section, D-Glucono...
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Lactic acid fermentation of cassava dough into agbelima.
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.
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2017-01-01
Summary In this work, autochthonous lactic acid bacteria (LAB) were isolated from chia (Salvia hispanica L.) dough and selected on the basis of the kinetics of acidification and proteolytic activity. Strain no. C8, identified as Lactobacillus plantarum C8, was selected and used as starter to obtain chia sourdough. Lactic acid fermentation increased the organic acid mass fractions (lactic, acetic and phenyl lactic acids to 12.3 g, 1.0 g and 23.8 µg per kg of dough respectively), and antioxidant activities, which increased by approx. 33–40% compared to unfermented chia flour dough. In addition, total phenolic content increased 25% and its composition was strongly modified after 24 h of fermentation by L. plantarum C8. Chlorogenic acid was only found in the fermented dough (2.5 mg/g), while ferulic acid was detected from the beginning of fermentation, being 32% higher in chia sourdough (5.6 mg/g). The use of fermented chia sourdough improved the overall characteristics of white bread, including physical (e.g. reduced hardness and chewiness of the crumb) and antioxidant properties (25% on average), compared to the white bread. These results indicate that the use of chia sourdough could be a promising alternative to improve the technological and antioxidant properties of wheat bread. In addition, this work has shown, for the first time, that lactic acid bacterium is able to ferment chia dough, improving its overall characteristics. PMID:29089851
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NASA Astrophysics Data System (ADS)
Dong, Wenjie; Shen, Zheng; Peng, Boyu; Gu, Minyan; Zhou, Xuefei; Xiang, Bo; Zhang, Yalei
2016-05-01
Lactic acid is an important platform molecule in the synthesis of a wide range of chemicals. However, in aqueous solutions without alkali, its efficient preparation via the direct catalysis of sugars is hindered by a side dehydration reaction to 5-hydroxymethylfurfural due to Brønsted acid, which originates from organic acids. Herein, we report that a previously unappreciated combination of common two metal mixed catalyst (Zn-Sn-Beta) prepared via solid-state ion exchange synergistically promoted this reaction. In water without a base, a conversion exceeding 99% for sucrose with a lactic acid yield of 54% was achieved within 2 hours at 190 °C under ambient air pressure. Studies of the acid and base properties of the Zn-Sn-Beta zeolite suggest that the introduction of Zn into the Sn-Beta zeolite sequentially enhanced both the Lewis acid and base sites, and the base sites inhibited a series of side reactions related to fructose dehydration to 5-hydroxymethylfurfural and its subsequent decomposition.
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Dong, Wenjie; Shen, Zheng; Peng, Boyu; Gu, Minyan; Zhou, Xuefei; Xiang, Bo; Zhang, Yalei
2016-01-01
Lactic acid is an important platform molecule in the synthesis of a wide range of chemicals. However, in aqueous solutions without alkali, its efficient preparation via the direct catalysis of sugars is hindered by a side dehydration reaction to 5-hydroxymethylfurfural due to Brønsted acid, which originates from organic acids. Herein, we report that a previously unappreciated combination of common two metal mixed catalyst (Zn-Sn-Beta) prepared via solid-state ion exchange synergistically promoted this reaction. In water without a base, a conversion exceeding 99% for sucrose with a lactic acid yield of 54% was achieved within 2 hours at 190 °C under ambient air pressure. Studies of the acid and base properties of the Zn-Sn-Beta zeolite suggest that the introduction of Zn into the Sn-Beta zeolite sequentially enhanced both the Lewis acid and base sites, and the base sites inhibited a series of side reactions related to fructose dehydration to 5-hydroxymethylfurfural and its subsequent decomposition. PMID:27222322
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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.
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2015-09-01
Scientific International Inc., Hampton, NH) at 22°C. Lactic acid (LA) and cell free potassium (K+) were measured using point of care clinical blood...equilibrium maintained by adenosine triphosphate (ATP) dependent potassium pumps [17]. Lactic acid accumulation was more pronounced in the first 21 days...Hct hematocrit Hgb hemoglobin K+ cell free potassium LA lactic acid pRBC packed red blood cell PS phosphatidylserine
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Rhee, Mun Su; Moritz, Brelan E.; Xie, Gary
Bacillus coagulans is a ubiquitous soil bacterium that grows at 50-55 C and pH 5.0 and fer- ments various sugars that constitute plant biomass to L (+)-lactic acid. The ability of this spo- rogenic lactic acid bacterium to grow at 50-55 C and pH 5.0 makes this organism an attrac- tive microbial biocatalyst for production of optically pure lactic acid at industrial scale not only from glucose derived from cellulose but also from xylose, a major constituent of hemi- cellulose. This bacterium is also considered as a potential probiotic. Complete genome se- quence of a representative strain, B. coagulans strainmore » 36D1, is presented and discussed.« less
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Comparative genomics of the lactic acid bacteria
DOE Office of Scientific and Technical Information (OSTI.GOV)
Makarova, K.; Slesarev, A.; Wolf, Y.
Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive genemore » loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.« less
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NASA Astrophysics Data System (ADS)
Nurhayati, Rifa; Miftakhussolikhah; Frediansyah, Andri; Lailatul Rachmah, Desy
2017-12-01
Type 2 diabetes is a disease that caused by the failure of insulin secretion by the beta cells of the pancreas and insulin resistance in peripheral levels. One therapy for diabetics is by inhibiting the activity of α-glucosidase. Lactic acid bacteria have the ability to inhibit of α-glucosidase activity. The aims of this research was to isolation and screening of lactic acid bacteria from ganyong tuber (Canna Edulis) and kimpul tuber (Xanthosoma sagittifolium), which has the ability to inhibit the activity of α-glucosidase. Eightteen isolates were identified as lactic acid bacteria and all of them could inhibit the activity of α-glukosidase. The GN 8 isolate was perform the highest inhibition acivity.
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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.
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Rhee, Mun Su; Moritz, Brélan E.; Xie, Gary; Glavina del Rio, T.; Dalin, E.; Tice, H.; Bruce, D.; Goodwin, L.; Chertkov, O.; Brettin, T.; Han, C.; Detter, C.; Pitluck, S.; Land, Miriam L.; Patel, Milind; Ou, Mark; Harbrucker, Roberta; Ingram, Lonnie O.; Shanmugam, K. T.
2011-01-01
Bacillus coagulans is a ubiquitous soil bacterium that grows at 50-55 °C and pH 5.0 and ferments various sugars that constitute plant biomass to L (+)-lactic acid. The ability of this sporogenic lactic acid bacterium to grow at 50-55 °C and pH 5.0 makes this organism an attractive microbial biocatalyst for production of optically pure lactic acid at industrial scale not only from glucose derived from cellulose but also from xylose, a major constituent of hemicellulose. This bacterium is also considered as a potential probiotic. Complete genome sequence of a representative strain, B. coagulans strain 36D1, is presented and discussed. PMID:22675583
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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
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USDA-ARS?s Scientific Manuscript database
The naturally occurring compound, fumaric acid, was evaluated as a potential preservative for the long-term storage of cucumbers. Fumaric acid inhibited growth of lactic acid bacteria (LAB) in an acidified cucumber juice medium model system resembling conditions that could allow preservation of cucu...
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Bae, Y-M; Lee, S-Y
2015-08-01
In this study, the effectiveness of combining each of seven types of acids with 3% salt as a treatment against pathogens was investigated in laboratory media and acidified food. When 0.5% malic, 0.5% tartaric, 0.5% citric or 0.25% phosphoric acid was combined with 3% salt, there was a higher reduction in Gram-negative bacteria (Escherichia coli O157:H7 and Salmonella Typhimurium) compared to when using acid alone. However, when 0.5% acetic, 0.5% propionic or 0.25% lactic acid was combined with 3% salt, the salt provided protection against the acid treatment. However, the antagonistic effects of acetic, propionic and lactic acid seen with Gram-negative bacteria were not observed in Listeria monocytogenes. Antagonistic effects were similarly observed when E. coli O157:H7 was treated with acetic acid and salt in food. These results show that the addition of salt increases the resistance of Gram-negative bacteria to acid treatments when using acetic, propionic and lactic acid. This study shows that antagonistic effects were observed when Gram-negative bacteria were treated with organic acids of simple structure. It may provide useful information for understanding the acid resistance mechanism of Gram-negative bacteria and developing methods for preserving acidified food. © 2015 The Society for Applied Microbiology.
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N'tcha, Christine; Sina, Haziz; Kayodé, Adéchola Pierre Polycarpe; Gbenou, Joachim D.
2017-01-01
The aim of this study was to investigate the antibacterial effect of the crude starter “kpètè-kpètè” and lactic acid bacteria used during the production of “tchoukoutou.” To achieve this, a total of 11 lactic acid bacteria and 40 starter samples were collected from four communes. The samples were tested on 29 gram + and − strains by disk diffusion method. The minimum inhibitory and bactericidal concentrations of starter and lactic acid bacteria were determined by conventional methods. Organic acids, sugar, and volatile compounds were determined using the HPLC method. The “kpètè-kpètè” displays a high antibacterial activity against the tested strains. The most sensitive strain was S. epidermidis (12.5 mm) whereas the resistance strain was Proteus mirabilis (8 mm). All the tested ferment has not any inhibitory effect on Enterococcus faecalis. The lactic acid bacteria isolates of Parakou showed the highest (17.48 mm) antibacterial activity whereas the smallest diameter was obtained with the ferment collected from Boukoumbé (9.80 mm). The starters' chemical screening revealed the presence of tannins, anthocyanin flavonoids, triterpenes, steroids, reducing compounds, and mucilage O-glycosides. These compounds are probably the source of recorded inhibition effect. The lactic acid bacteria of the “kpètè-kpètè” could be used to develop a food ingredient with probiotic property. PMID:28367445
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Lactic Acid and Biosurfactants Production from Residual Cellulose Films.
Portilla Rivera, Oscar Manuel; Arzate Martínez, Guillermo; Jarquín Enríquez, Lorenzo; Vázquez Landaverde, Pedro Alberto; Domínguez González, José Manuel
2015-11-01
The increasing amounts of residual cellulose films generated as wastes all over the world represent a big scale problem for the meat industry regarding to environmental and economic issues. The use of residual cellulose films as a feedstock of glucose-containing solutions by acid hydrolysis and further fermentation into lactic acid and biosurfactants was evaluated as a method to diminish and revalorize these wastes. Under a treatment consisting in sulfuric acid 6% (v/v); reaction time 2 h; solid liquid ratio 9 g of film/100 mL of acid solution, and temperature 130 °C, 35 g/L of glucose and 49% of solubilized film was obtained. From five lactic acid strains, Lactobacillus plantarum was the most suitable for metabolizing the glucose generated. The process was scaled up under optimized conditions in a 2-L bioreactor, producing 3.4 g/L of biomass, 18 g/L of lactic acid, and 15 units of surface tension reduction of a buffer phosphate solution. Around 50% of the cellulose was degraded by the treatment applied, and the liqueurs generated were useful for an efficient production of lactic acid and biosurfactants using L. plantarum. Lactobacillus bacteria can efficiently utilize glucose from cellulose films hydrolysis without the need of clarification of the liqueurs.
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[Bio-ecological control of chronic liver disease and encephalopathy].
Bengmark, S; Di Cocco, P; Clemente, K; Corona, L; Angelico, R; Manzia, T; Famulari, A; Pisani, F; Orlando, G
2011-08-01
Minimal encephalopathy was originally associated with chronic liver disease but is increasingly associated with most other chronic diseases and particularly with diabetes and also chronic disorders in other organs: kidneys, lungs, thyroid and with obesity. It is increasingly with dramatically increased and more or less permanent increase in systemic inflammation, most likely a result of Western lifestyle. Frequent physical exercise and intake of foods rich in vitamins, antioxidants, fibres, lactic acid bacteria etc in combination with reduction in intake of refined and processed foods is known to reduce systemic inflammation and prevent chronic diseases. Some lactic acid bacteria, especially Lb paracasei, lb plantarum and pediococcus pentosaceus have proven effective to reduce inflammation and eliminate encephalopathy. Significant reduction in blood ammonia levels and endotoxin levels were reported in parallel to improvement of liver disease. Subsequent studies with other lactic acid bacteria seem to demonstrate suppression of inflammation and one study also provides evidence of clinical improvement.
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Modelling of Batch Lactic Acid Fermentation in the Presence of Anionic Clay
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
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Erginkaya, Z; Turhan, E U; Tatlı, D
2018-01-01
In this study, the antibiotic resistance (AR) of lactic acid bacteria (LAB) isolated from traditional Turkish fermented dairy products was investigated. Yogurt, white cheese, tulum cheese, cokelek, camız cream and kefir as dairy products were collected from various supermarkets. Lactic acid bacteria such as Lactobacillus spp., Streptococcus spp., Bifidobacterium spp., and Enterecoccus spp. were isolated from these dairy products. Lactobacillus spp. were resistant to vancomycin (58%), erythromycin (10.8%), tetracycline (4.3%), gentamicin (28%), and ciprofloxacin (26%). Streptococcus spp. were resistant to vancomycin (40%), erythromycin (10%), chloramphenicol (10%), gentamicin (20%), and ciprofloxacin (30%). Bifidobacterium spp. were resistant to vancomycin (60%), E 15 (6.6%), gentamicin (20%), and ciprofloxacin (33%). Enterococcus spp. were resistant to vancomycin (100%), erythromycin (100%), rifampin (100%), and ciprofloxacin (100%). As a result, LAB islated from dairy products in this study showed mostly resistance to vancomycin.
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Aroma composition of shalgam: a traditional Turkish lactic acid fermented beverage.
Tanguler, Hasan; Selli, Serkan; Sen, Kemal; Cabaroglu, Turgut; Erten, Huseyin
2017-06-01
Shalgam, a traditional red, cloudy and sour soft beverage, is produced by lactic acid fermentation of black carrot, sourdough, salt, bulgur flour, turnip and adequate water. The present study was designed to characterize the volatile compounds of shalgam obtained from different methods. The aroma compounds of shalgams produced by traditional and direct methods, and addition of Lactic acid bateria (LAB) cultures were examined. Volatile components of shalgam samples were extracted by liquid-liquid extraction technique with pentane/dichloromethane and analyzed by gas chromatography-mass spectrometry (GC-MS). Sixty aroma compounds were identified in shalgam samples including 20 terpenes, 9 esters, 9 alcohols, 5 volatile acids, 6 volatile phenols, 5 lactones, 3 naphthalenes, 2 carbonyl compounds and 1 C13-norisoprenoids. It was found that the aroma profiles of shalgams were quite similar. However, the total volatile content of the shalgam samples increased with addition of Lb. plantarum .
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Bioconversion Using Lactic Acid Bacteria: Ginsenosides, GABA, and Phenolic Compounds.
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.
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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.
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Sonal S. Karkhanis; Laurent M. Matuana; Nicole M. Stark; Ronald C. Sabo
2017-01-01
This study was aimed to identify the best approach for incorporating cellulose nanocrystals (CNCs) into a poly(lactic acid) (PLA) matrix by examining two different CNC addition approaches. The first approach consisted of melt blending PLA and CNCs in a three-piece internal mixer whereas the second method involved the direct dry mixing of PLA and CNCs. The prepared...
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Farrag, Mohamed; Drobish, Julie K; Puhl, Henry L; Kim, Joyce S; Herold, Paul B; Kaufman, Marc P; Ruiz-Velasco, Victor
2017-12-01
Chronic limb ischaemia, characterized by inflammatory mediator release and a low extracellular pH, leads to acid-sensing ion channel (ASIC) activation and reflexively increases mean arterial pressure; endomorphin release is also increased under inflammatory conditions. We examined the modulation of ASIC currents by endomorphins in sensory neurons from rats with freely perfused and ligated femoral arteries: peripheral artery disease (PAD) model. Endomorphins potentiated sustained ASIC currents in both groups of dorsal root ganglion neurons, independent of mu opioid receptor stimulation or G protein activation. Intra-arterial administration of lactic acid (to simulate exercising muscle and evoke a pressor reflex), endomorphin-2 and naloxone resulted in a significantly greater pressor response than lactic acid alone, while administration of APETx2 inhibited endomorphin's enhancing effect in both groups. These results suggest a novel role for endomorphins in modulating ASIC function to effect lactic acid-mediated reflex increase in arterial pressure in patients with PAD. Chronic muscle ischaemia leads to accumulation of lactic acid and other inflammatory mediators with a subsequent drop in interstitial pH. Acid-sensing ion channels (ASICs), expressed in thin muscle afferents, sense the decrease in pH and evoke a pressor reflex known to increase mean arterial pressure. The naturally occurring endomorphins are also released by primary afferents under ischaemic conditions. We examined whether high affinity mu opioid receptor (MOR) agonists, endomorphin-1 (E-1) and -2 (E-2), modulate ASIC currents and the lactic acid-mediated pressor reflex. In rat dorsal root ganglion (DRG) neurons, exposure to E-2 in acidic solutions significantly potentiated ASIC currents when compared to acidic solutions alone. The potentiation was significantly greater in DRG neurons isolated from rats whose femoral arteries were ligated for 72 h. Sustained ASIC current potentiation was also observed in neurons pretreated with pertussis toxin, an uncoupler of G proteins and MOR. The endomorphin-mediated potentiation was a result of a leftward shift of the activation curve to higher pH values and a slight shift of the inactivation curve to lower pH values. Intra-arterial co-administration of lactic acid and E-2 led to a significantly greater pressor reflex than lactic acid alone in the presence of naloxone. Finally, E-2 effects were inhibited by pretreatment with the ASIC3 blocker APETx2 and enhanced by pretreatment with the ASIC1a blocker psalmotoxin-1. These findings have uncovered a novel role of endomorphins by which the opioids can enhance the lactic acid-mediated reflex increase in arterial pressure that is MOR stimulation-independent and APETx2-sensitive. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.
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Liang, Xili; Sun, Chao; Chen, Bosheng; Du, Kaiqian; Yu, Ting; Luang-In, Vijitra; Lu, Xingmeng; Shao, Yongqi
2018-06-01
Insects constitute the most abundant and diverse animal class and act as hosts to an extraordinary variety of symbiotic microorganisms. These microbes living inside the insects play critical roles in host biology and are also valuable bioresources. Enterococcus mundtii EMB156, isolated from the larval gut (gut pH >10) of the model organism Bombyx mori (Lepidoptera: Bombycidae), efficiently produces lactic acid, an important metabolite for industrial production of bioplastic materials. E. mundtii EMB156 grows well under alkaline conditions and stably converts various carbon sources into lactic acid, offering advantages in downstream fermentative processes. High-yield lactic acid production can be achieved by the strain EMB156 from renewable biomass substrates under alkaline pretreatments. Single-molecule real-time (SMRT) sequencing technology revealed its 3.01 Mbp whole genome sequence. A total of 2956 protein-coding sequences, 65 tRNA genes, and 6 rRNA operons were predicted in the EMB156 chromosome. Remarkable genomic features responsible for lactic acid fermentation included key enzymes involved in the pentose phosphate (PP)/glycolytic pathway, and an alpha amylase and xylose isomerase were characterized in EMB156. This genomic information coincides with the phenotype of E. mundtii EMB156, reflecting its metabolic flexibility in efficient lactate fermentation, and established a foundation for future biotechnological application. Interestingly, enzyme activities of amylase were quite stable in high-pH broths, indicating a possible mechanism for strong EMB156 growth in an alkaline environment, thereby facilitating lactic acid production. Together, these findings implied that valuable lactic acid-producing bacteria can be discovered efficiently by screening under the extremely alkaline conditions, as exemplified by gut microbial symbionts of Lepidoptera insects.
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Minervini, Fabio; Lattanzi, Anna; De Angelis, Maria; Gobbetti, Marco
2012-01-01
Seven mature type I sourdoughs were comparatively back-slopped (80 days) at artisan bakery and laboratory levels under constant technology parameters. The cell density of presumptive lactic acid bacteria and related biochemical features were not affected by the environment of propagation. On the contrary, the number of yeasts markedly decreased from artisan bakery to laboratory propagation. During late laboratory propagation, denaturing gradient gel electrophoresis (DGGE) showed that the DNA band corresponding to Saccharomyces cerevisiae was no longer detectable in several sourdoughs. Twelve species of lactic acid bacteria were variously identified through a culture-dependent approach. All sourdoughs harbored a certain number of species and strains, which were dominant throughout time and, in several cases, varied depending on the environment of propagation. As shown by statistical permutation analysis, the lactic acid bacterium populations differed among sourdoughs propagated at artisan bakery and laboratory levels. Lactobacillus plantarum, Lactobacillus sakei, and Weissella cibaria dominated in only some sourdoughs back-slopped at artisan bakeries, and Leuconostoc citreum seemed to be more persistent under laboratory conditions. Strains of Lactobacillus sanfranciscensis were indifferently found in some sourdoughs. Together with the other stable species and strains, other lactic acid bacteria temporarily contaminated the sourdoughs and largely differed between artisan bakery and laboratory levels. The environment of propagation has an undoubted influence on the composition of sourdough yeast and lactic acid bacterium microbiotas. PMID:22635989
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Effect of Incubation Time and Sucrose Addition on the Characteristics of Cheese Whey Yoghurt
NASA Astrophysics Data System (ADS)
Nurhartadi, E.; Utami, R.; Nursiwi, A.; Sari, A. M.; Widowati, E.; Sanjaya, A. P.; Esnadewi, E. A.
2017-04-01
The effect of incubation time and concentration of sucrose addition on the characteristics of cheese whey yogurt (lactic acid content, pH, total lactic acid bacteria, antioxidant activity, viscosity) and sensory characteristics (color, odor, flavor, consistency, and overalls) were investigated. The cheese whey yogurt fermentation process was carried out for 24h and 36h with the addition of sucrose 8, 10, and 12% (w/w) of total solid, respectively. The results showed that the lactic acid content, total lactic acid bacteria, antioxidant activity, and viscosity of cheese whey yogurt were affected by the incubation time and sucrose addition. The level of pH of yogurt which was incubated at 24h and 36h were relatively in the same levels, which were 4.51 up to 4.63. Due the sensory characteristic of cheese whey yogurt the panellists gave the high score for the cheese whey yogurt which was incubated at 24h and sucrose addition 12% (w/w) of total solid. The cheese whey yogurt has 0.41% lactic acid content; pH 4.51; 7.09 log total lactic acid bacteria cells / ml; 5.78% antioxidant activity; and 5.97 cP viscosity. The best sensory and physico-chemical characteristic of cheese whey yogurt was achieved by 24h incubation time and 12% concentration of sucrose addition.
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21 CFR 133.195 - Swiss and emmentaler cheese.
Code of Federal Regulations, 2014 CFR
2014-04-01
... treated with hydrogen peroxide/catalase, and is subjected to the action of lactic acid-producing and propionic acid-producing bacterial cultures. One or more of the clotting enzymes specified in paragraph (b... firm. The acidity of the whey at this point, calculated as lactic acid, does not exceed 0.13 percent...
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21 CFR 133.195 - Swiss and emmentaler cheese.
Code of Federal Regulations, 2012 CFR
2012-04-01
... treated with hydrogen peroxide/catalase, and is subjected to the action of lactic acid-producing and propionic acid-producing bacterial cultures. One or more of the clotting enzymes specified in paragraph (b... firm. The acidity of the whey at this point, calculated as lactic acid, does not exceed 0.13 percent...
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21 CFR 133.195 - Swiss and emmentaler cheese.
Code of Federal Regulations, 2013 CFR
2013-04-01
... treated with hydrogen peroxide/catalase, and is subjected to the action of lactic acid-producing and propionic acid-producing bacterial cultures. One or more of the clotting enzymes specified in paragraph (b... firm. The acidity of the whey at this point, calculated as lactic acid, does not exceed 0.13 percent...
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Preparation of lactic acid bacteria fermented wheat-yoghurt mixtures.
Magala, Michal; Kohajdová, Zlatica; Karovičová, Jolana
2013-01-01
Tarhana, a wheat-yoghurt fermented mixture, is considered as a good source of saccharides, proteins, some vitamins and minerals. Moreover, their preparation is inexpensive and lactic acid fermentation offers benefits like product preservation, enhancement of nutritive value and sensory properties improvement. The aim of this work was to evaluate changes of some chemical parameters during fermentation of tarhana, when the level of salt and amount of yoghurt used were varied. Some functional and sensory characteristics of the fi nal product were also determined. Chemical analysis included determination of pH, titrable acidity, content of reducing saccharides, lactic, acetic and citric acid. Measured functional properties of tarhana powder were foaming capacity, foam stability, water absorption capacity, oil absorption capacity and emulsifying activity. Tarhana soups samples were evaluated for their sensory characteristics (colour, odor, taste, consistency and overall acceptability). Fermentation of tarhana by lactic acid bacteria and yeasts led to decrease in pH, content of reducing saccharides and citric acid, while titrable acidity and concentration of lactic and acetic acid increased. Determination of functional properties of tarhana powder showed, that salt absence and increased amount of yoghurt in tarhana recipe reduced foaming capacity and oil absorption capacity, whereas foam stability and water absorption capacity were improved. Sensory evaluation of tarhana soups showed that variations in tarhana recipe adversly affected sensory parameters of fi nal products. Variations in tarhana recipe (salt absence, increased proportion of yoghurt) led to changes in some chemical parameters (pH, titrable acidity, reducing saccharides, content of lactic, acetic and citric acid). Functional properties were also affected with changed tarhana recipe. Sensory characteristics determination showed, that standard tarhana fermented for 144 h had the highest overall acceptability.
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Pretreatment of corn stover by solid acid for d-lactic acid fermentation.
Wang, Xiqing; Wang, Gang; Yu, Xiaoxiao; Chen, Huan; Sun, Yang; Chen, Guang
2017-09-01
Solid acid is a new acid that is safe and green, which has been widely used in the fields of acid pickling. In this study, we adopted solid acid to pretreat corn stover and used the pretreated corn stover in the fermentation of d-lactic acid. Finally, we obtained optimal conditions for the pretreatment of corn stover by solid acid: digestion temperature of 120°C, digestion time of 80min, and solid acid concentration of 1.5%. Then adding cellulase of 30FPU/g, the conversion rate of glucose reached 71.06% after enzymatic hydrolysis for 72h. In addition, the changes of corn stover structure after pretreatment were further represented by using scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). At the same time, we used the pretreated corn stover as fermentation substrate and Lactobacillus. delbrueckii sp. bulgaricus as the starting strain to produce d-lactic acid. The yield reached 18g/L, with the optical purity being 99%e.e. This research has provided a new way to comprehensively utilizae corn stover. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Yang, Jinsong; Tan, Haisheng; Cai, Yimin
2016-07-01
The natural lactic acid bacteria (LAB) population, chemical composition, and silage fermentation of fruit residues were studied. Eighty-two strains of LAB were isolated from fruit residues such as banana leaf and stem, pineapple peel, and papaya peel. All strains were gram-positive and catalase-negative bacteria, and they were divided into 7 groups (A-G) according to morphological and biochemical characters. Strains in groups A to F were rods, and group G was cocci. Group F produced gas from glucose; other groups did not. Groups A to C and F formed dl-lactic acid, whereas groups D, E, and G formed l-lactic acid. Based on the 16S rRNA gene sequence and DNA-DNA hybridization analysis, groups A to G strains were identified as Lactobacillus plantarum (54.9% of the total isolates), Lactobacillus paraplantarum (3.6%), Lactobacillus nagelii (8.5%), Lactobacillus perolens (4.9%), Lactobacillus casei (11.0%), Lactobacillus fermentum (9.8%), and Enterococcus gallinarum (7.3%), respectively. Lactobacillus plantarum and Lactobacillus casei are the most frequently isolated from fruit residues as a dominant species, and they could grow at a lower pH conditions and produce more lactic acid than other isolates. Pineapple and papaya peels contained higher crude protein (11.5-13.8%) and water-soluble carbohydrate (16.8-22.4%), but lower acid detergent fiber contents (21.2 to 26.4%) than banana stems and leaves (8.2% crude protein, 42.8% acid detergent fiber, and 5.1% water-soluble carbohydrate). Compared with banana stem and leaf silages, the pineapple and papaya peel silages were well preserved with a lower pH and higher lactate content. The study suggests that the fruit residues contain excellent LAB species and abundant feed nutrients, and that they can be preserved as silage to be potential food resources for livestock. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
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Mateluna, Patricio; Salvatierra, Ariel; Solis, Simón; Nuñez, Gabriel; Pimentel, Paula
2018-05-12
Prunus species have been classified as moderately sensitive to root hypoxia, but with a certain intrageneric tolerance degree to oxygen deficiency. Previously, RNA-seq analysis described the transcriptomic reconfiguration of two Prunus rootstocks contrasting to root hypoxia, which included the shift from aerobic to anaerobic metabolism. Here, we studied the relationship between lactate accumulation and the functionality of an aquaporin differentially expressed in 'Mariana 2624', a plum-based (Prunus cerasifera x Prunus munsoniana) rootstock tolerant to root hypoxia stress, and 'Mazzard F12/1', a cherry-based (Prunus avium) rootstock sensitive to root hypoxia stress. In the root hypoxia-sensitive rootstock, higher levels of lactate and LDH1 gene expression were found in roots exposed to oxygen deprivation. Concomitantly, we detected an increase in the mRNA abundance of Prunus spp. NIP1;1, a putative lactic acid transporter. Intriguingly, the high expression of PruavNIP1;1 is not linked to a lower lactic acid content in the roots of 'Mazzard F12/1'. To study this phenomenon, we calculated the force required for the transit of a lactic acid molecule through Prunus spp. NIP1;1 channels. Comparing the calculated forces, we identified steric hindrances in PruavNIP1;1 given by the residues Phe107 and Trp88 in the NPA region and ar/R filter, respectively. The functionality of both channels was corroborated by the restoration of the lactic acid transport and the differential lactic acid sensitive-phenotypes of the yeast strain Δjen1 complemented with PruavNIP1;1 and PrucxmNIP1;1. Our findings provide new insights into the mechanisms involved in determining hypoxia tolerance between closely related species, such as plum and cherry. Copyright © 2018 Elsevier GmbH. All rights reserved.
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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.
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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.
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Lactic acid bacteria in the quality improvement and depreciation of wine.
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.
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Juturu, Veeresh; Wu, Jin Chuan
2018-03-01
Thermophilic Bacillus coagulans JI12 was used to ferment hemicellulose hydrolysate obtained by acid hydrolysis of oil palm empty fruit bunch at 50 °C and pH 6, producing 105.4 g/L of l-lactic acid with a productivity of 9.3 g/L/H by fed-batch fermentation under unsterilized conditions. Simultaneous saccharification and fermentation (SSF) was performed at pH 5.5 and 50 °C to convert both hemicellulose hydrolysate and cellulose-lignin complex in the presence of Cellic Ctec2 cellulases using yeast extract (20 g/L) as the nitrogen source, giving 114.0 g/L of l-lactic acid with a productivity of 5.7 g/L/H. The SSF was also conducted by replacing yeast extract with equal amount of dry Bakers' yeast, achieving 120.0 g/L of l-lactic acid with a productivity of 4.3 g/L/H. To the best of our knowledge, these lactic acid titers and productivities are the highest ever reported from lignocellulose hydrolysates. © 2017 International Union of Biochemistry and Molecular Biology, Inc.
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21 CFR 184.1061 - Lactic acid.
Code of Federal Regulations, 2010 CFR
2010-04-01
... glucose, sucrose, or lactose, or by a procedure involving formation of lactonitrile from acetaldehyde and hydrogen cyanide and subsequent hydrolysis to lactic acid. (b) The ingredient meets the specifications of...
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21 CFR 184.1061 - Lactic acid.
Code of Federal Regulations, 2011 CFR
2011-04-01
... glucose, sucrose, or lactose, or by a procedure involving formation of lactonitrile from acetaldehyde and hydrogen cyanide and subsequent hydrolysis to lactic acid. (b) The ingredient meets the specifications of...
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Detoxification of sugarcane-derived hemicellulosic hydrolysate using a lactic acid producing strain.
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.
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Pittman, C I; Geornaras, I; Woerner, D R; Nightingale, K K; Sofos, J N; Goodridge, L; Belk, K E
2012-09-01
Lactic acid can reduce microbial contamination on beef carcass surfaces when used as a food safety intervention, but effectiveness when applied to the surface of chilled beef subprimal sections is not well documented. Studies characterizing bacterial reduction on subprimals after lactic acid treatment would be useful for validations of hazard analysis critical control point (HACCP) systems. The objective of this study was to validate initial use of lactic acid as a subprimal intervention during beef fabrication followed by a secondary application to vacuum-packaged product that was applied at industry operating parameters. Chilled beef subprimal sections (100 cm(2)) were either left uninoculated or were inoculated with 6 log CFU/cm(2) of a 5-strain mixture of Escherichia coli O157:H7, a 12-strain mixture of non-O157 Shiga toxin-producing E. coli (STEC), or a 5-strain mixture of nonpathogenic (biotype I) E. coli that are considered surrogates for E. coli O157:H7. Uninoculated and inoculated subprimal sections received only an initial or an initial and a second "rework" application of lactic acid in a custombuilt spray cabinet at 1 of 16 application parameters. After the initial spray, total inoculum counts were reduced from 6.0 log CFU/cm(2) to 3.6, 4.4, and 4.4 log CFU/cm(2) for the E. coli surrogates, E. coli O157:H7, and non-O157 STEC inoculation groups, respectively. After the second (rework) application, total inoculum counts were 2.6, 3.2, and 3.6 log CFU/cm(2) for the E. coli surrogates, E. coli O157:H7, and non-O157 STEC inoculation groups, respectively. Both the initial and secondary lactic acid treatments effectively reduced counts of pathogenic and nonpathogenic strains of E. coli and natural microflora on beef subprimals. These data will be useful to the meat industry as part of the HACCP validation process.
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Lefeber, Timothy; Janssens, Maarten; Camu, Nicholas; De Vuyst, Luc
2010-01-01
The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes. PMID:20889778
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Lefeber, Timothy; Janssens, Maarten; Camu, Nicholas; De Vuyst, Luc
2010-12-01
The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes.
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IN VITRO INTERACTIONS BETWEEN LACTIC ACID SOLUTION AND ART GLASS-IONOMER CEMENTS
Wang, Linda; Cefaly, Daniela Francisca Gigo; dos Santos, Janaína Lima; dos Santos, Jean Rodrigo; Lauris, José Roberto Pereira; Mondelli, Rafael Francisco Lia; Atta, Maria Teresa
2009-01-01
Objectives: Production of acids such as lactic acid contributes to establish a cariogenic environment that leads to dental substrate demineralization. Fluoride plays an important role in this case and, as fluoride-releasing materials, glass-ionomer cements are expected to contribute to minimize deleterious reactions. This study evaluated interactions of glass-ionomer cements used in atraumatic restorative treatment (ART-GICs) with an aqueous lactic acid solution, testing the null hypotheses that no changes occur in the pH of the solution or on the surface roughness and mass of the ART-GICs when exposed to lactic acid solution over a 6-week period. Material and Methods: Ketac Molar, Fuji IX, Vitro Molar and Magic Glass were tested, and compared to Filtek Z250 and Ketac Fil Plus as control groups. Six specimens of each material were made according to manufacturers' instructions. The pH of the solution and roughness and mass changes of each specimen were determined over 6 weeks. Each specimen was individually stored in 2 mL of 0.02 M lactic acid solution for 1 week, renewing the solution every week. pH of solution and mass of the specimens were monitored weekly, and surface roughness of the specimens was assessed before and at the end of the 6-week acid challenge. pH and mass data were analyzed statistically by repeated measures using one-way ANOVA and Tukey's post-hoc tests for each material. Paired t-tests were used for roughness analysis. Tukey's post-hoc tests were applied to verify differences of final roughness among the materials. Significance level was set at 5%. Results: The null hypotheses were partially rejected. All materials were able to increase the pH of the lactic acid solution and presented rougher surfaces after immersion, while mass change was minimal and generally not statistically significant. Conclusions: These findings can be helpful to predict the performance of these materials under clinical conditions. A protective action against the carious process with significant surface damage due to erosion may be expected. PMID:19668984
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Bao, Jianna; Xue, Xiaojia; Li, Kai; Chang, Xiaohua; Xie, Qing; Yu, Chengtao; Pan, Pengju
2017-07-20
Promoting the stereocomplexation ability of high-molecular-weight poly(l-lactic acid) (PLLA) and poly(d-lactic acid) (PDLA) is an efficient way to improve the thermal resistance of the resulting materials. Herein, we studied the competing crystallization kinetics, polymorphic crystalline structure, and lamellae structure of the PLLA/PDLA component in its miscible blends with poly(vinyl acetate) (PVAc) and proposed a method to improve the stereocomplexation ability of PLLA and PDLA through miscible blending with the other polymer. Crystallization of the PLLA/PDLA component is suppressed after the addition of PVAc, due to the dilution effect. The stereocomplexation ability of PLLA and PDLA is enhanced by blending with PVAc; this becomes more obvious at a high PVAc content (≥50 wt %) but less significant with the further increase of PLLA, PDLA molecular weights. Almost exclusive formation of SCs is achieved for PLLA and PDLA after blending with a large proportion of PVAc (e.g., 75 wt %). Incorporation of PVAc also facilitates the HC-to-SC structural reorganization upon heating. The increased chain mobility, decreased equilibrium melting point, and enhanced intermolecular interactions may account for the preferential stereocomplexation in PLLA/PDLA/PVAc blends.
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Pleissner, Daniel; Neu, Anna-Katrin; Mehlmann, Kerstin; Schneider, Roland; Puerta-Quintero, Gloria Inés; Venus, Joachim
2016-10-01
In this study, the lignocellulosic residue coffee pulp was used as carbon source in fermentative l(+)-lactic acid production using Bacillus coagulans. After thermo-chemical treatment at 121°C for 30min in presence of 0.18molL(-1) H2SO4 and following an enzymatic digestion using Accellerase 1500 carbon-rich hydrolysates were obtained. Two different coffee pulp materials with comparable biomass composition were used, but sugar concentrations in hydrolysates showed variations. The primary sugars were (gL(-1)) glucose (20-30), xylose (15-25), sucrose (5-11) and arabinose (0.7-10). Fermentations were carried out at laboratory (2L) and pilot (50L) scales in presence of 10gL(-1) yeast extract. At pilot scale carbon utilization and lactic acid yield per gram of sugar consumed were 94.65% and 0.78gg(-1), respectively. The productivity was 4.02gL(-1)h(-1). Downstream processing resulted in a pure formulation containing 937gL(-1)l(+)-lactic acid with an optical purity of 99.7%. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.
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Dynamic modeling of lactic acid fermentation metabolism with Lactococcus lactis.
Oh, Euhlim; Lu, Mingshou; Park, Changhun; Park, Changhun; Oh, Han Bin; Lee, Sang Yup; Lee, Jinwon
2011-02-01
A dynamic model of lactic acid fermentation using Lactococcus lactis was constructed, and a metabolic flux analysis (MFA) and metabolic control analysis (MCA) were performed to reveal an intensive metabolic understanding of lactic acid bacteria (LAB). The parameter estimation was conducted with COPASI software to construct a more accurate metabolic model. The experimental data used in the parameter estimation were obtained from an LC-MS/ MS analysis and time-course simulation study. The MFA results were a reasonable explanation of the experimental data. Through the parameter estimation, the metabolic system of lactic acid bacteria can be thoroughly understood through comparisons with the original parameters. The coefficients derived from the MCA indicated that the reaction rate of L-lactate dehydrogenase was activated by fructose 1,6-bisphosphate and pyruvate, and pyruvate appeared to be a stronger activator of L-lactate dehydrogenase than fructose 1,6-bisphosphate. Additionally, pyruvate acted as an inhibitor to pyruvate kinase and the phosphotransferase system. Glucose 6-phosphate and phosphoenolpyruvate showed activation effects on pyruvate kinase. Hexose transporter was the strongest effector on the flux through L-lactate dehydrogenase. The concentration control coefficient (CCC) showed similar results to the flux control coefficient (FCC).
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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.
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Upreti, P; McKay, L L; Metzger, L E
2006-02-01
Cheddar cheese ripening involves the conversion of lactose to glucose and galactose or galactose-6-phosphate by starter and nonstarter lactic acid bacteria. Under ideal conditions (i.e., where bacteria grow under no stress of pH, water activity, and salt), these sugars are mainly converted to lactic acid. However, during ripening of cheese, survival and growth of bacteria occurs under the stressed condition of low pH, low water activity, and high salt content. This forces bacteria to use alternate biochemical pathways resulting in production of other organic acids. The objective of this study was to determine if the level and type of organic acids produced during ripening was influenced by calcium (Ca) and phosphorus (P), residual lactose, and salt-to-moisture ratio (S/M) of cheese. Eight cheeses with 2 levels of Ca and P (0.67 and 0.47% vs. 0.53 and 0.39%, respectively), lactose at pressing (2.4 vs. 0.78%), and S/M (6.4 vs. 4.8%) were manufactured. The cheeses were analyzed for organic acids (citric, orotic, pyruvic, lactic, formic, uric, acetic, propanoic, and butyric acids) and residual sugars (lactose, galactose) during 48 wk of ripening using an HPLC-based method. Different factors influenced changes in concentration of residual sugars and organic acids during ripening and are discussed in detail. Our results indicated that the largest decrease in lactose and the largest increase in lactic acid occurred between salting and d 1 of ripening. It was interesting to observe that although the lactose content in cheese was influenced by several factors (Ca and P, residual lactose, and S/M), the concentration of lactic acid was influenced only by S/M. More lactic acid was produced in low S/M treatments compared with high S/M treatments. Although surprising for Cheddar cheese, a substantial amount (0.2 to 0.4%) of galactose was observed throughout ripening in all treatments. Minor changes in the levels of citric, uric, butyric, and propanoic acids were observed during early ripening, whereas during later ripening, a substantial increase was observed. A gradual decrease in orotic acid and a gradual increase in pyruvic acid content of the cheeses were observed during 12 mo of ripening. In contrast, acetic acid did not show a particular trend, indicating its role as an intermediate in a biochemical pathway, rather than a final product.
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21 CFR 184.1768 - Sodium lactate.
Code of Federal Regulations, 2011 CFR
2011-04-01
... the sodium salt of lactic acid. It is prepared commercially by the neutralization of lactic acid with... manufacturing practice. (d) Prior sanctions for this ingredient different from the uses established in this...
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21 CFR 184.1768 - Sodium lactate.
Code of Federal Regulations, 2013 CFR
2013-04-01
... the sodium salt of lactic acid. It is prepared commercially by the neutralization of lactic acid with... manufacturing practice. (d) Prior sanctions for this ingredient different from the uses established in this...
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21 CFR 184.1768 - Sodium lactate.
Code of Federal Regulations, 2012 CFR
2012-04-01
... the sodium salt of lactic acid. It is prepared commercially by the neutralization of lactic acid with... manufacturing practice. (d) Prior sanctions for this ingredient different from the uses established in this...
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21 CFR 184.1768 - Sodium lactate.
Code of Federal Regulations, 2010 CFR
2010-04-01
... the sodium salt of lactic acid. It is prepared commercially by the neutralization of lactic acid with... manufacturing practice. (d) Prior sanctions for this ingredient different from the uses established in this...
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Rong, Xianfang; Yuan, Weien; Lu, Yi; Mo, Xiaofen
2014-01-01
Poly(lactic-co-glycolic acid) (PLGA) and/or poly(lactic-acid) (PLA) microspheres are important drug delivery systems. This study investigated eye biocompatibility and safety of PLGA/PLA microspheres through intravitreal injection in rabbits. Normal New Zealand rabbits were randomly selected and received intravitreal administration of different doses (low, medium, or high) of PLGA/PLA microspheres and erythropoietin-loaded PLGA/PLA microspheres. The animals were clinically examined and sacrificed at 1, 2, 4, 8, and 12 weeks postadministration, and retinal tissues were prepared for analysis. Retinal reactions to the microspheres were evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end staining and glial fibrillary acidic protein immunohistochemistry. Retinal structure changes were assessed by hematoxylin and eosin staining and transmission electron microscopy. Finally, retinal function influences were explored by the electroretinography test. Terminal deoxynucleotidyl transferase-mediated dUTP nick end staining revealed no apoptotic cells in the injected retinas; immunohistochemistry did not detect any increased glial fibrillary acidic protein expression. Hematoxylin and eosin staining and transmission electron microscopy revealed no micro- or ultrastructure changes in the retinas at different time points postintravitreal injection. The electroretinography test showed no significant influence of scotopic or photopic amplitudes. The results demonstrated that PLGA/PLA microspheres did not cause retinal histological changes or functional damage and were biocompatible and safe enough for intravitreal injection in rabbits for controlled drug delivery.
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Soria, M Cecilia; Audisio, M Carina
2014-12-01
Bacillus cereus is an endospore-forming, Gram-positive bacterium able to cause foodborne diseases. Lactic acid bacteria (LAB) are known for their ability to synthesize organic acids and bacteriocins, but the potential of these compounds against B. cereus has been scarcely documented in food models. The present study has examined the effect of the metabolites produced by Lactobacillus johnsonii CRL1647 and Enterococcus faecium SM21 on the viability of select B. cereus strains. Furthermore, the effect of E. faecium SM21 metabolites against B. cereus strains has also been investigated on a rice food model. L. johnsonii CRL1647 produced 128 mmol/L of lactic acid, 38 mmol/L of acetic acid and 0.3 mmol/L of phenyl-lactic acid. These organic acids reduced the number of vegetative cells and spores of the B. cereus strains tested. However, the antagonistic effect disappeared at pH 6.5. On the other hand, E. faecium SM21 produced only lactic and acetic acid (24.5 and 12.2 mmol/L, respectively) and was able to inhibit both vegetative cells and spores of the B. cereus strains, at a final fermentation pH of 5.0 and at pH 6.5. This would indicate the action of other metabolites, different from organic acids, present in the cell-free supernatant. On cooked rice grains, the E. faecium SM21 bacteriocin(s) were tested against two B. cereus strains. Both of them were significantly affected within the first 4 h of contact; whereas B. cereus BAC1 cells recovered after 24 h, the effect on B. cereus 1 remained up to the end of the assay. The LAB studied may thus be considered to define future strategies for biological control of B. cereus.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Volkova, V.N.; Zakharova, E.A.; Khustenko, L.A.
The number of supporting electrolytes for stripping voltammetry with photochemical oxygen deactivation was broadened. The following agents are recommended: formic, lactic, tartaric, citric, and malonic acids at pH 2-4; salts of lactic, tartaric, and citric acids at pH 6-7; and salts of lactic, tartaric, citric, and glutaric acids at pH 12-14. A rapid method was developed for simultaneously determining Zn, Cd, Pb, and Cu in a 0.5 M formic acid supporting electrolyte. The method is chemometrically sound and cost-effective.
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Lignin poly(lactic acid) copolymers
Olsson, Johan Vilhelm; Chung, Yi-Lin; Li, Russell Jingxian; Waymouth, Robert; Sattely, Elizabeth; Billington, Sarah; Frank, Curtis W.
2017-02-14
Provided herein are graft co-polymers of lignin and poly(lactic acid) (lignin-g-PLA copolymer), thermoset and thermoplastic polymers including them, methods of preparing these polymers, and articles of manufacture including such polymers.
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Fermentation and recovery process for lactic acid production
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.
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Nazer, Rakan I; Alburikan, Khalid A
2017-05-30
Metformin associated lactic acidosis (MALA) is a rare but lethal complication. There is no consensus regarding when to stop and resume metformin in patients who undergo coronary artery bypass grafting (CABG). This study aimed to determine if uninterrupted metformin administration in patients with diabetes undergoing CABG increases the risk of lactic acidosis. Over a span of 12 months (2015-2016), 127 patients with type 2 diabetes underwent isolated CABG. Of those, 41 patients (32%) continued taking metformin and 86 patients (68%) took other antidiabetic agents. Patients taking metformin took the drug until the day of surgery and resumed taking it 3 h after extubation. There were no differences in clinical outcomes or complications between groups. Serial measurement of cardiac, liver, and kidney biomarkers were similar between groups. The mean peak lactic acid level was significantly higher in the non-metformin users (5.4 ± 2.6 vs. 7.4 ± 4.1 mmol/l; P = 0.001). Multivariable logistic regression analysis identified the need for vasopressor administration as an independent predictor of lactic acidosis (odds ratio: 7.3, 95% confidence interval: 2.5-20.6; P < 0.001). In the absence of risk factors associated with persistent lactic acidosis, such as shock or acute kidney or liver injury, continued peri-operative metformin administration was not associated with the occurrence of lactic acidosis in patients undergoing CABG. Elevated lactic acid levels seem to be directly related to tissue anoxia caused by escalating vasopressor support after surgery.
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Kobayashi, M; Takatori, T; Iwadate, K; Nakajima, M
1996-10-25
We examined the changes in adenosine triphosphate (ATP), lactic acid, adenosine diphosphate (ADP) and adenosine monophosphate (AMP) in five different rat muscles after death. Rigor mortis has been thought to occur simultaneously in dead muscles and hence to start in small muscles sooner than in large muscles. In this study we found that the rate of decrease in ATP was significantly different in each muscle. The greatest drop in ATP was observed in the masseter muscle. These findings contradict the conventional theory of rigor mortis. Similarly, the rates of change in ADP and lactic acid, which are thought to be related to the consumption or production of ATP, were different in each muscle. However, the rate of change of AMP was the same in each muscle.
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Butanol is cytotoxic to Lactococcus lactis while ethanol and hexanol are cytostatic.
Hviid, Anne-Mette Meisner; Ruhdal-Jensen, Peter; Kilstrup, Mogens
2017-04-01
Lactic acid bacteria currently used extensively by the dairy industry have a superior tolerance towards short-chain alcohols, which makes them interesting targets for use in future bio-refineries. The mechanism underlying the alcohol tolerance of lactic acid bacteria has so far received little attention. In the present study, the physiological alcohol stress response of Lactococcus lactis subsp. cremoris MG1363 towards the primary, even-chain alcohols ethanol, butanol and hexanol, was characterized. The alcohol tolerance of L. lactis was found to be comparable to those reported for highly alcohol-resistant lactic acid bacteria. Combined results from alcohol survival rate, live/dead staining, and a novel usage of the β-galactosidase assay, revealed that while high concentrations of ethanol and hexanol were cytostatic to L. lactis, high concentrations of butanol were cytotoxic, causing irreparable damages to the cell membrane.
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High piezoelectric performance of poly(lactic acid) film manufactured by solid-state extrusion
NASA Astrophysics Data System (ADS)
Yoshida, Mitsunobu; Onogi, Takayuki; Onishi, Katsuki; Inagaki, Takuma; Tajitsu, Yoshiro
2014-09-01
Recently, the application of uniaxially stretched poly(l-lactic acid) (PLLA) films to speakers, actuators, and pressure sensors has been attempted, taking advantage of their piezoelectric performance. However, the shear piezoelectric constant d14 of uniaxially stretched PLLA film is conventionally 6-10 pC N-1. To realize a high sensitivity of pressure sensors, compact speakers, and actuators, and a low driving voltage, further improvement of the piezoelectric performance is desired. In this study, we carried out solid-state extrusion (SSE) to stretch and orient poly(d-lactic acid) (PDLA) and verified its effects on piezoelectric performance. By SSE, we were able to improve the mechanical strength and elastic modulus of PDLA samples. Furthermore, the d14 of the samples was significantly increased to approximately 20 pC N-1.
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Sgibnev, Andrey; Kremleva, Elena
2017-06-01
We studied as hydrogen peroxide, lactic acid, or surfactants from clinical isolates of vaginal lactobacilli and cell-free supernatants from probiotic strain LCR35 can influence on the sensitivity of opportunistic bacteria to antibiotics. We found that the most effective in increasing sensitivity to antibiotics were hydrogen peroxide and surfactants or their combination but no lactic acid. In some cases, the effect of the composition of hydrogen peroxide and surfactants was clearly higher than the sum of effects of these substances alone. With using of the supernatant of LCR35 was shown that the combination of surfactant and lactate has greater effect compared with surfactants alone. In concluding, metabolites of vaginal lactobacilli are suitable for the role of "antibiotic assistants" and it can help solve the problems the antibiotic resistance.
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Hu, Yunzi; Daoud, Walid A.; Cheuk, Kevin Ka Leung; Lin, Carol Sze Ki
2016-01-01
Polycondensation and ring-opening polymerization are two important polymer synthesis methods. Poly(lactic acid), the most typical biodegradable polymer, has been researched extensively from 1900s. It is of significant importance to have an up-to-date review on the recent improvement in techniques for biodegradable polymers. This review takes poly(lactic acid) as the example to present newly developed polymer synthesis techniques on polycondensation and ring-opening polymerization reported in the recent decade (2005–2015) on the basis of industrial technique modifications and advanced laboratory research. Different polymerization methods, including various solvents, heating programs, reaction apparatus and catalyst systems, are summarized and compared with the current industrial production situation. Newly developed modification techniques for polymer properties improvement are also discussed based on the case of poly(lactic acid). PMID:28773260
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Melting of α'- and α-crystals of poly(lactic acid)
NASA Astrophysics Data System (ADS)
Di Lorenzo, Maria Laura; Androsch, René
2016-05-01
The influence of chain structure on thermal stability of α'-crystals of poly(lactic acid) (PLA) with high L-lactic acid content (96-100 %) is detailed in this contribution. α'-crystals of PLA grow at temperatures below 120 °C, and spontaneously transform into stable α-modification during heating. Using conventional differential scanning calorimetry (DSC) and fast scanning chip calorimetry (FSC), a wide range of scanning rates, between about 10-1 and 102 K s-1 could be tested. It was found that reorganization of disordered α'-crystals into stable α-crystals can be suppressed by fast heating. The critical heating rate needed to completely melt α'-crystals and to avoid formation of α-crystals on continuation of heating varies with the chain composition, and decreases upon increase of the D-lactic acid content in the PLA chain.
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Dong, Shi-Jun; Lin, Xiang-Hua; Li, Hao
2015-11-01
During the industrial bioethanol fermentation, Saccharomyces cerevisiae cells are often stressed by bacterial contaminants, especially lactic acid bacteria. Generally, lactic acid bacteria contamination can inhibit S. cerevisiae cell growth through secreting lactic acid and competing with yeast cells for micronutrients and living space. However, whether are there still any other influences of lactic acid bacteria on yeast or not? In this study, Lactobacillus plantarum ATCC 8014 was co-cultivated with S. cerevisiae S288c to mimic the L. plantarum contamination in industrial bioethanol fermentation. The contaminative L. plantarum-associated expression changes of genes involved in carbohydrate and energy related metabolisms in S. cerevisiae cells were determined by quantitative real-time polymerase chain reaction to evaluate the influence of L. plantarum on carbon source utilization and energy related metabolism in yeast cells during bioethanol fermentation. Contaminative L. plantarum influenced the expression of most of genes which are responsible for encoding key enzymes involved in glucose related metabolisms in S. cerevisiae. Specific for, contaminated L. plantarum inhibited EMP pathway but promoted TCA cycle, glyoxylate cycle, HMP, glycerol synthesis pathway, and redox pathway in S. cerevisiae cells. In the presence of L. plantarum, the carbon flux in S. cerevisiae cells was redistributed from fermentation to respiratory and more reducing power was produced to deal with the excess NADH. Moreover, L. plantarum contamination might confer higher ethanol tolerance to yeast cells through promoting accumulation of glycerol. These results also highlighted our knowledge about relationship between contaminative lactic acid bacteria and S. cerevisiae during bioethanol fermentation. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Liu, Jianguo; Wang, Qunhui; Zou, Hui; Liu, Yingying; Wang, Juan; Gan, Kemin; Xiang, Juan
2013-11-01
The (13) C isotope tracer method was used to investigate the glucose metabolic flux distribution and regulation in Lactobacillus amylophilus to improve lactic acid production using kitchen waste saccharified solution (KWSS). The results demonstrate that L. amylophilus is a homofermentative bacterium. In synthetic medium, 60.6% of the glucose entered the Embden-Meyerhof-Parnas (EMP) to produce lactic acid, whereas 36.4% of the glucose entered the pentose phosphate metabolic pathway (HMP). After solid-liquid separation of the KWSS, the addition of Fe(3+) during fermentation enhanced the NADPH production efficiency and increased the NADH content. The flux to the EMP was also effectively increased. Compared with the control (60.6% flux to EMP without Fe(3+) addition), the flux to the EMP with the addition of Fe(3+) (74.3%) increased by 23.8%. In the subsequent pyruvate metabolism, Fe(3+) also increased lactate dehydrogenase activity, and inhibited alcohol dehydrogenase, pyruvate dehydrogenase and pyruvate carboxylase, thereby increasing the lactic acid production to 9.03 g l(-1) , an increase of 8% compared with the control. All other organic acid by-products were lower than in the control. However, the addition of Zn(2+) showed an opposite effect, decreasing the lactic acid production. In conclusion it is feasible and effective means using GC-MS, isotope experiment and MATLAB software to integrate research the metabolic flux distribution of lactic acid bacteria, and the results provide the theoretical foundation for similar metabolic flux distribution. © 2013 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.
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Degradation in the fatigue crack growth resistance of human dentin by lactic acid
Orrego, Santiago; Xu, Huakun; Arola, Dwayne
2017-01-01
The oral cavity frequently undergoes localized changes in chemistry and level of acidity, which threatens the integrity of the restorative material and supporting hard tissue. The focus of this study was to evaluate the changes in fatigue crack growth resistance of dentin and toughening mechanisms caused by lactic acid exposure. Compact tension specimens of human dentin were prepared from unrestored molars and subjected to Mode I opening mode cyclic loads. Fatigue crack growth was achieved in samples from mid- and outer-coronal dentin immersed in either a lactic acid solution or neutral conditions. An additional evaluation of the influence of sealing the lumens by dental adhesive was also conducted. A hybrid analysis combining experimental results and finite element modeling quantified the contribution of the toughening mechanisms for both environments. The fatigue crack growth responses showed that exposure to lactic acid caused a significant reduction (p≤0.05) of the stress intensity threshold for cyclic crack extension, and a significant increase (p≤0.05) in the incremental fatigue crack growth rate for both regions of coronal dentin. Sealing the lumens had negligible influence on the fatigue resistance. The hybrid analysis showed that the acidic solution was most detrimental to the extrinsic toughening mechanisms, and the magnitude of crack closure stresses operating in the crack wake. Exposing dentin to acidic environments contributes to the development of caries, but it also increases the chance of tooth fractures via fatigue-related failure and at lower mastication forces. PMID:28183665
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Fessard, Amandine; Kapoor, Ashish; Patche, Jessica; Assemat, Sophie; Hoarau, Mathilde; Bourdon, Emmanuel; Bahorun, Theeshan; Remize, Fabienne
2017-01-01
Tropical fruits like pineapple, papaya, mango, and beverages such as green or black teas, represent an underestimated source of antioxidants that could exert health-promoting properties. Most food processing technologies applied to fruit beverages or teas result in an impairment of inherent nutritional properties. Conversely, we hypothesise that lactic acid fermentation may constitute a promising route to maintain and even improve the nutritional qualities of processed fruits. Using specific growth media, lactic acid bacteria were selected from the fruit phyllosphere diversity and fruit juice, with the latter undergoing acidification kinetics analyses and characterised for exopolysaccharide production. Strains able to ferment tropical fruit juices or teas into pleasant beverages, within a short time, were of particular interest. Strains Weissella cibaria 64 and Leuconostoc mesenteroides 12b, able to increase antioxidant activity, were specifically studied as potential starters for lactic fermented pineapple juice. PMID:28489022
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Poly-L/D-lactic acid anchors are associated with reoperation and failure of SLAP repairs.
Park, Min Jung; Hsu, Jason E; Harper, Carl; Sennett, Brian J; Huffman, G Russell
2011-10-01
This study investigates factors associated with failure and reoperation after glenoid labrum repair. We studied a nonconcurrent cohort of consecutive patients undergoing arthroscopic superior labrum repair at a single institution by 2 fellowship-trained surgeons over a 10-year period. There were 348 patients included in this study with a mean age of 33.4 years (95% confidence interval [CI], 32.1 to 35.9) and a mean clinical follow-up of 12.3 months (95% CI, 10.9 to 13.8). The overall reoperation rate was 6.3%, with a revision labrum repair rate of 4.3%. Subsequent surgery and failure after arthroscopic labrum repair were significantly correlated with Workers' Compensation claims (odds ratio [OR], 4.6; P < .001; 95% CI, 1.8 to 11.7), the use of tobacco (OR, 12.0; P = .03; 95% CI, 1.2 to 114.9), and the use of absorbable poly-L/D-lactic acid (PLDLA) anchors (100% correlation, P < .001). The OR for having repeat surgery was 12.7 (95% CI, 4.9 to 32.9; P < .001) with poly-96L/4D-lactic acid (Mini-Revo; Linvatec, Largo, FL) and also increased with the use of poly-70L/30D-lactic acid (Bio-Fastak and Bio-Suturetak; Arthrex, Naples, FL) anchor material (P = .04) after removal of the patients exposed to poly-96L/4D-lactic acid anchors. The rates of repeat surgery with PLDLA anchors from Linvatec and PLDLA anchors from Arthrex were 24% and 4%, respectively. None of the patients treated with nonabsorbable suture anchors (polyether ether ketone or metallic) returned to the operating room (P < .001). After we controlled for associated factors in a multivariate analysis, the use of absorbable anchors, in particular poly-96L/4D-lactic acid anchors (OR, 14.7; P < .001), and having a work-related injury (OR, 8.1; P < .001) remained independent factors associated with both repeat surgery and revision superior labrum repair. Bioabsorbable PLDLA anchor material led to significantly more SLAP repair failures and reoperations compared with nonabsorbable suture anchors. Our recommendation is that glenoid labrum repairs be performed with nondegradable material and, specifically, that the use of anchors composed of PLDLA material should be avoided. Copyright © 2011 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.
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Martin, Leigh R; Mezyk, Stephen P; Mincher, Bruce J
2009-01-08
Lactic acid is a major component of the TALSPEAK process planned for use in the separation of trivalent lanthanide and actinide elements. This acid acts both as a buffer and to protect the actinide complexant from radiolytic damage. However, there is little kinetic information on the reaction of water radiolysis species with lactic acid, particularly under the anticipated process conditions of aerated aqueous solution at pH approximately 3, where oxidizing reactions are expected to dominate. Here we have determined temperature-dependent reaction rate constants for the reactions of the hydroxyl radical with lactic acid and the lactate ion. For lactic acid this rate constant is given by the following equation: ln k(1) = (23.85 +/- 0.19) - (1120 +/- 54)/T, corresponding to an activation energy of 9.31 +/- 0.45 kJ mol(-1) and a room temperature reaction rate constant of (5.24 +/- 0.35) x 10(8) M(-1) s(-1) (24.0 degrees C). For the lactate ion, the temperature-dependent rate constant is given by ln k(2) = (24.83 +/- 0.14) - (1295 +/- 42)/T, for an activation energy of 10.76 +/- 0.35 kJ mol(-1) and a room temperature value of (7.77 +/- 0.50) x 10(8) M(-1) s(-1) (22.2 degrees C). These kinetic data have been combined with autotitration measurements to determine the temperature-dependent behavior of the lactic acid pK(a) value, allowing thermodynamic parameters for the acid dissociation to be calculated as DeltaH(o) = -10.75 +/- 1.77 kJ mol(-1), DeltaS(o) = -103.9 +/- 6.0 J K(-1) mol(-1) and DeltaG(o) = 20.24 +/- 2.52 kJ mol(-1) at low ionic strength.
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USDA-ARS?s Scientific Manuscript database
A “green juice”, obtained by squeezing freshly harvested alfalfa leaves amended with a commercial lactic acid bacterial inoculant, was readily fermented by 7- to 21-d incubation at room temperature to obtain lactic acid at concentrations of 12-46 g l-1, along with additional acetic and succinic acid...
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el-Ziney, M G; De Meyer, H; Debevere, J M
1997-03-03
The influence of different organic acids (lactic, acetic, formic and propionic acids) at equimolar concentrations of undissociated acid with pH range of 3.9, 5.8, on the aerobic and anaerobic growth and survival kinetics of the virulent strain of Y. enterocolitica IP 383 0:9, was determined in tryptone soy broth at 4 degrees C. Growth and survival data were analyzed and fitted by a modification of the Whiting and Cygnarowicz-Provost model, using the Minpack software library. Initial generation times, initial specific growth rates, lag time and dead rate were subsequently calculated from the model parameters. The results demonstrate that the inhibitory effects of the acids were divided into two categories dependent upon pH. At high pH (5.8) the order of inhibition was formic acid > acetic acid > propionic acid > lactic acid, whereas at lower pH it became formic acid > lactic acid > acetic acid > propionic acid. The inhibitory effect of lactic acid is enhanced under anaerobic condition. Nevertheless, when the organism was cultured anaerobically, it was shown to be more tolerant to formic and acetic acids. Moreover, these variables (type of organic acid, pH and atmosphere) did not lead to the loss of the virulence plasmid in growing and surviving cells. The mechanism of inhibitory effect for each of the acids are also discussed.
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Anaerobic microbial dissolution of lead and production of organic acids
Francis, A.J.; Dodge, C.; Chendrayan, K.; Quinby, H.L.
1987-04-16
The present invention related to an anaerobic bacterial culture of Clostridium sp. ATCC No. 53464 which solubilizes lead oxide under anaerobic conditions in coal and industrial wastes and therefore presents a method of removing lead from such wastes before they are dumped into the environment. The rat of lead dissolution during logarithmic growth of the bacteria in 40 ml medium containing 3.32 ..mu..moles of lead as lead oxide was 0.042 ..mu..moles m1/sup /-/1/ hr/sup /-/1/. Dissolution of lead oxide by the bacterial isolate is due to the production of metabolites and acidity in the culture medium. The major metabolites are acetic, butyric and lactic acid. The major metabolites are acetic, butyric and lactic acid. Clostridium sp. ATCC No. 53464 can be used in the recovery of the strategic metals from ores and wastes and also for the production of lactic acid for commercial purposes. The process yields large quantities of lactic acid as well as lead complexed in a stable form with said acids. 4 figs., 3 tabs.
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Acid hydrolysis of Curcuma longa residue for ethanol and lactic acid fermentation.
Nguyen, Cuong Mai; Nguyen, Thanh Ngoc; Choi, Gyung Ja; Choi, Yong Ho; Jang, Kyoung Soo; Park, Youn-Je; Kim, Jin-Cheol
2014-01-01
This research examines the acid hydrolysis of Curcuma longa waste, to obtain the hydrolysate containing lactic acid and ethanol fermentative sugars. A central composite design for describing regression equations of variables was used. The selected optimum condition was 4.91% sulphuric acid, 122.68°C and 50 min using the desirability function under the following conditions: the maximum reducing sugar (RS) yield is within the limited range of the 5-hydroxymethylfurfural (HMF) and furfural concentrations. Under the condition, the obtained solution contained 144 g RS/L, 0.79 g furfural/L and 2.59 g HMF/L and was directly fermented without a detoxification step. The maximum product concentration, average productivity, RS conversion and product yield were 115.36 g/L, 2.88 g/L/h, 89.43% and 64% for L-lactic acid; 113.92 g/L, 2.59 g/L/h, 88.31% and 63.29% for D-lactic acid; and 55.03 g/L, 1.38 g/L/h, 42.66 and 30.57%, respectively, for ethanol using a 7-L jar fermenter. Copyright © 2013. Published by Elsevier Ltd.
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Blends of low molecular weight of poly lactic acid (PLA) with gondorukem (gum rosin)
NASA Astrophysics Data System (ADS)
Kaavessina, Mujtahid; Distantina, Sperisa; Chafidz, Achmad; Utama, Aditya; Anggraeni, Venisa Mega Puteri
2018-02-01
The utilization of plastic was increasing as well as the increasing its demand in wide range application. Consequently, the number of plastic litter will increase and make more serious environmental problems. This research concerns to minimize waste problems by designing biodegradable plastic. In this research, biodegradable plastic was made of poly lactic acid (PLA) and gondorukem (Gum rosin, Resina colophonium) as the plasticizer. The effect of gondorukem towards PLA properties such as rheology and degradability was investigated. The research divided into two steps: (i) the polycondensation of lactic acid (LA) and (ii) modification of obtained poly lactic acid. In the first step, polycondensation was done in N2 atmosphere (138°C) for 30 hours and added 0.1 %w of SnCl2 as catalyst. Bulk modification was conducted by blending of gondurukem in varied weight (0.5, 1, and 2 g in 10 g of PLA). Furthermore, the modified PLA was analyzed its molecular structure, biodegradability and rheological property. The presence of gondorukem enhanced the biodegradability of poly lactic acid. Gondorukem could act as the plasticizer. It is confirmed that the complex viscosity of PLA melt decreased upon the addition of gondorukem