Immobilization: A Revolution in Traditional Brewing

NASA Astrophysics Data System (ADS)

Virkajärvi, Ilkka; Linko, Matti

In nature many micro-organisms tend to bind to solid surfaces. This tendency has long been utilized in a number of processes, for example in producing vinegar and acetic acid in bioreactors filled with wood shavings. Acetobacteria are attached to the surface of these shavings. In modern technical language: they are immobilized. Also yeast cells can be immobilized. In the brewing industry this has been the basis for maintaining efficient, continuous fermentation in bioreactors with very high yeast concentrations. The most dramatic change in brewing over recent years has been the replacement of traditional lagering of several weeks by a continuous process in which the residence time is only about 2h. Continuous primary fermentation is used on a commercial scale in New Zealand. In this process, instead of a carrier, yeast is retained in reactors by returning it partly after separation. In many pilot scale experiments the primary fermentation is shortened from about 1week to 1-2days using immobilized yeast reactors. When using certain genetically modified yeast strains no secondary fermentation is needed, and the total fermentation time in immobilized yeast reactors can therefore be shortened to only 2days.

Ethanol fermentation integrated with PDMS composite membrane: An effective process.

PubMed

Fu, Chaohui; Cai, Di; Hu, Song; Miao, Qi; Wang, Yong; Qin, Peiyong; Wang, Zheng; Tan, Tianwei

2016-01-01

The polydimethylsiloxane (PDMS) membrane, prepared in water phase, was investigated in separation ethanol from model ethanol/water mixture and fermentation-pervaporation integrated process. Results showed that the PDMS membrane could effectively separate ethanol from model solution. When integrated with batch ethanol fermentation, the ethanol productivity was enhanced compared with conventional process. Fed-batch and continuous ethanol fermentation with pervaporation were also performed and studied. 396.2-663.7g/m(2)h and 332.4-548.1g/m(2)h of total flux with separation factor of 8.6-11.7 and 8-11.6, were generated in the fed-batch and continuous fermentation with pervaporation scenario, respectively. At the same time, high titre ethanol production of ∼417.2g/L and ∼446.3g/L were also achieved on the permeate side of membrane in the two scenarios, respectively. The integrated process was environmental friendly and energy saving, and has a promising perspective in long-terms operation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mechanistic simulation of batch acetone-butanol-ethanol (ABE) fermentation with in situ gas stripping using Aspen Plus™.

PubMed

Darkwah, Kwabena; Nokes, Sue E; Seay, Jeffrey R; Knutson, Barbara L

2018-05-22

Process simulations of batch fermentations with in situ product separation traditionally decouple these interdependent steps by simulating a separate "steady state" continuous fermentation and separation units. In this study, an integrated batch fermentation and separation process was simulated for a model system of acetone-butanol-ethanol (ABE) fermentation with in situ gas stripping, such that the fermentation kinetics are linked in real-time to the gas stripping process. A time-dependent cell growth, substrate utilization, and product production is translated to an Aspen Plus batch reactor. This approach capitalizes on the phase equilibria calculations of Aspen Plus to predict the effect of stripping on the ABE fermentation kinetics. The product profiles of the integrated fermentation and separation are shown to be sensitive to gas flow rate, unlike separate steady state fermentation and separation simulations. This study demonstrates the importance of coupled fermentation and separation simulation approaches for the systematic analyses of unsteady state processes.

Contamination issues in continuous fermentation for ethanol production

USDA-ARS?s Scientific Manuscript database

Continuous fermentation processes are employed by corn wet milling plants all over world to convert starch to ethanol. Contaminations by bacterial microorganisms like Lactobacillus and wild yeasts like Brettanomyces are common and result in lower ethanol yields. Contaminants compete with inoculate...

JPRS Report, Science & Technology, Japan

DTIC Science & Technology

1988-11-10

stage of microbial culture and fermentation through the stage of product isolation and purification. The information is expected to become an...controlled so that a process can be manipulated normally and safely. For example, in a bioreactor process mainly involving fermentation , the author and his...10) Electron microscope (11) Jar fermenter Continuous centrifuge Examples of equipment used in cell fusion research (1) Autotable Heated vibrating

Change of Monascus pigment metabolism and secretion in different extractive fermentation process.

PubMed

Chen, Gong; Tang, Rui; Tian, Xiaofei; Qin, Peng; Wu, Zhenqiang

2017-06-01

Monascus pigments that were generally produced intracellularly from Monascus spp. are important natural colorants in food industry. In this study, change of pigment metabolism and secretion was investigated through fed-batch extractive fermentation and continuous extractive fermentation. The biomass, secreting rate of pigment and total pigment yield closely correlated with the activated time of extractive fermentation as well as the composition of feeding nutrients. Metal ions played a key role in both the cell growth and pigment metabolism. Nitrogen source was necessary for a high productivity of biomass but not for high pigment yield. Furthermore, fermentation period for the fed-batch extractive fermentation could be reduced by 18.75% with a nitrogen source free feeding medium. Through a 30-day continuous extractive fermentation, the average daily productivity for total pigments reached 74.9 AU day -1 with an increase by 32.6 and 296.3% compared to that in a 6-day conventional batch fermentation and a 16-day fed-batch extractive fermentation, respectively. At the meantime, proportions of extracellular pigments increased gradually from 2.7 to 71.3%, and yellow pigments gradually became dominated in both intracellular and extracellular pigments in the end of continuous extractive fermentation. This findings showed that either fed-batch or continuous extractive fermentation acted as a promising method in the efficient production of Monascus pigments.

Use of a biparticle fluidized-bed bioreactor for the continuous and simultaneous fermentation and purification of lactic acid

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

Kaufman, E. N.; Cooper, S. P.; Clement, S. L.

A continuous biparticle fluidized bed reactor is developed for the simultaneous fermentation and purification of lactic acid. In this processing scheme, bacteria are immobilized in gelatin beads and are fluidized in a columnar reactor. Solid particles with sorbent capacity for the product are introduced at the top of the reactor, and fall counter currently to the biocatalyst, effecting in situ removal of the inhibitory product, while also controlling reactor pH at optimal levels. Initial long-term fermentation trials using immobilized Lactobacillus delbreuckii have demonstrated a 12 fold increase in volumetric productivity during adsorbent addition as opposed to control fermentations in themore » same reactor. Unoptimized regeneration of the loaded sorbent has effected at least an 8 fold concentration of lactic acid, and a 68 fold enhancement in separation from glucose compared to original levels in the fermentation broth. The benefits of this reactor system as opposed to conventional batch fermentation are discussed in terms of productivity and process economics.« less

Use of a biparticle fluidized-bed bioreactor for the continuous and simultaneous fermentation and purification of lactic acid

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

Kaufman, E.N.; Cooper, S.P.; Clement, S.L.

1995-12-31

A continuous biparticle fluidized-bed reactor is developed for the simultaneous fermentation and purification of lactic acid. In this processing scheme, bacteria are immobilized in gelatin beads and are fluidized in a columnar reactor. Solid particles with sorbent capacity for the product are introduced at the top of the reactor, and fall counter currently to the biocatalyst, effecting in situ removal of the inhibitory product, while also controlling reactor pH at optimal levels. Initial long-term fermentation trials using immobilized Lactobacillus delbreuckii have demonstrated a 12-fold increase in volumetric productivity during absorbent addition as opposed to control fermentations in the same reactor.more » Unoptimized regeneration of the loaded sorbent has effected at least an eightfold concentration of lactic acid and a 68-fold enhancement in separation from glucose compared to original levels in the fermentation broth. The benefits of this reactor system as opposed to conventional batch fermentation are discussed in terms of productivity and process economics.« less

Dynamics of the microbial community during continuous methane fermentation in continuously stirred tank reactors.

PubMed

Tang, Yue-Qin; Shigematsu, Toru; Morimura, Shigeru; Kida, Kenji

2015-04-01

Methane fermentation is an attractive technology for the treatment of organic wastes and wastewaters. However, the process is difficult to control, and treatment rates and digestion efficiency require further optimization. Understanding the microbiology mechanisms of methane fermentation is of fundamental importance to improving this process. In this review, we summarize the dynamics of microbial communities in methane fermentation chemostats that are operated using completely stirred tank reactors (CSTRs). Each chemostat was supplied with one substrate as the sole carbon source. The substrates include acetate, propionate, butyrate, long-chain fatty acids, glycerol, protein, glucose, and starch. These carbon sources are general substrates and intermediates of methane fermentation. The factors that affect the structure of the microbial community are discussed. The carbon source, the final product, and the operation conditions appear to be the main factors that affect methane fermentation and determine the structure of the microbial community. Understanding the structure of the microbial community during methane fermentation will guide the design and operation of practical wastewater treatments. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Study on the correlation between volatile fatty acids and gas production in dry fermentation of kitchen waste

NASA Astrophysics Data System (ADS)

Li, Qiangqiang; Ma, Yunfeng; Du, Boying; Wang, Qi; Hu, Qiongqiong; Bian, Yushan

2018-02-01

In this study, continuous kitchen waste fermentation and anaerobic digestion experiments were conducted to analyze the gas production potential, and to study the correlation between gas production rate and volatile fatty acid (VFAs) and its component concentration. During the experiment, the total solid(TS) concentration of the reaction system was increased by adding the kitchen waste, analysis of kitchen waste dry fermentation process to start, run, imbalance and imbalance after recovery and the parameters in the process of realizing the change trend and influencing factors of dry fermentation process, pH and ammonia concentration.

Mechanisms and kinetics of cellulose fermentation for protein production

NASA Technical Reports Server (NTRS)

Dunlap, C. A.

1971-01-01

The development of a process (and ancillary processing and analytical techniques) to produce bacterial single-cell protein of good nutritional quality from waste cellulose is discussed. A fermentation pilot plant and laboratory were developed and have been in operation for about two years. Single-cell protein (SCP) can be produced from sugarcane bagasse--a typical agricultural cellulosic waste. The optimization and understanding of this process and its controlling variables are examined. Both batch and continuous fermentation runs have been made under controlled conditions in the 535 liter pilot plant vessel and in the laboratory 14-liter fermenters.

A modified indirect mathematical model for evaluation of ethanol production efficiency in industrial-scale continuous fermentation processes.

PubMed

Canseco Grellet, M A; Castagnaro, A; Dantur, K I; De Boeck, G; Ahmed, P M; Cárdenas, G J; Welin, B; Ruiz, R M

2016-10-01

To calculate fermentation efficiency in a continuous ethanol production process, we aimed to develop a robust mathematical method based on the analysis of metabolic by-product formation. This method is in contrast to the traditional way of calculating ethanol fermentation efficiency, where the ratio between the ethanol produced and the sugar consumed is expressed as a percentage of the theoretical conversion yield. Comparison between the two methods, at industrial scale and in sensitivity studies, showed that the indirect method was more robust and gave slightly higher fermentation efficiency values, although fermentation efficiency of the industrial process was found to be low (~75%). The traditional calculation method is simpler than the indirect method as it only requires a few chemical determinations in samples collected. However, a minor error in any measured parameter will have an important impact on the calculated efficiency. In contrast, the indirect method of calculation requires a greater number of determinations but is much more robust since an error in any parameter will only have a minor effect on the fermentation efficiency value. The application of the indirect calculation methodology in order to evaluate the real situation of the process and to reach an optimum fermentation yield for an industrial-scale ethanol production is recommended. Once a high fermentation yield has been reached the traditional method should be used to maintain the control of the process. Upon detection of lower yields in an optimized process the indirect method should be employed as it permits a more accurate diagnosis of causes of yield losses in order to correct the problem rapidly. The low fermentation efficiency obtained in this study shows an urgent need for industrial process optimization where the indirect calculation methodology will be an important tool to determine process losses. © 2016 The Society for Applied Microbiology.

Electricity generation from synthesis gas by microbial processes: CO fermentation and microbial fuel cell technology.

PubMed

Kim, Daehee; Chang, In Seop

2009-10-01

A microbiological process was established to harvest electricity from the carbon monoxide (CO). A CO fermenter was enriched with CO as the sole carbon source. The DGGE/DNA sequencing results showed that Acetobacterium spp. were enriched from the anaerobic digester fluid. After the fermenter was operated under continuous mode, the products were then continuously fed to the microbial fuel cell (MFC) to generate electricity. Even though the conversion yield was quite low, this study proved that synthesis gas (syn-gas) can be converted to electricity with the aid of microbes that do not possess the drawbacks of metal catalysts of conventional methods.

Impact of pseudo-continuous fermentation on the ethanol tolerance of Scheffersomyces stipitis.

PubMed

Liang, Meng; Kim, Min Hea; He, Qinghua Peter; Wang, Jin

2013-09-01

In this work we conducted the pseudo-continuous fermentation, i.e., continuous fermentation with cell retention, using Scheffersomyces stipitis, and studied its effect on ethanol tolerance of the strain. During the fermentation experiments, S. stipitis was adapted to a mild concentration of ethanol (20-26 g/L) for two weeks. Two substrates (glucose and xylose) were used in different fermentation experiments. After fermentation, various experiments were performed to evaluate the ethanol tolerance of adapted cells and unadapted cells. Compared to the unadapted cells, the viability of adapted cells increased by 8 folds with glucose as the carbon source and 6 folds with xylose as the carbon source following exposure to 60 g/L ethanol for 2 h. Improved ethanol tolerance of the adapted cells was also revealed in the effects of ethanol on plasma membrane permeability, extracellular alkalization and acidification. The mathematical modeling of cell leakage, extracellular alkalization and acidification revealed that cells cultured on glucose show better ethanol tolerance than cells cultured on xylose but the differences become smaller for adapted cells. The results show that pseudo-continuous fermentation can effectively improve cell's ethanol tolerance due to the environmental pressure during the fermentation process. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Acetone-butanol-ethanol from sweet sorghum juice by an immobilized fermentation-gas stripping integration process.

PubMed

Cai, Di; Wang, Yong; Chen, Changjing; Qin, Peiyong; Miao, Qi; Zhang, Changwei; Li, Ping; Tan, Tianwei

2016-07-01

In this study, sweet sorghum juice (SSJ) was used as the substrate in a simplified ABE fermentation-gas stripping integration process without nutrients supplementation. The sweet sorghum bagasse (SSB) after squeezing the fermentable juice was used as the immobilized carrier. The results indicated that the productivity of ABE fermentation process was improved by gas stripping integration. A total 24g/L of ABE solvents was obtained from 59.6g/L of initial sugar after 80h of fermentation with gas stripping. Then, long-term of fed-batch fermentation with continuous gas stripping was further performed. 112.9g/L of butanol, 44.1g/L of acetone, 9.5g/L of ethanol (total 166.5g/L of ABE) was produced in overall 312h of fermentation. At the same time, concentrated ABE product was obtained in the condensate of gas stripping. Copyright © 2016 Elsevier Ltd. All rights reserved.

Production of fuel ethanol from bamboo by concentrated sulfuric acid hydrolysis followed by continuous ethanol fermentation.

PubMed

Sun, Zhao-Yong; Tang, Yue-Qin; Iwanaga, Tomohiro; Sho, Tomohiro; Kida, Kenji

2011-12-01

An efficient process for the production of fuel ethanol from bamboo that consisted of hydrolysis with concentrated sulfuric acid, removal of color compounds, separation of acid and sugar, hydrolysis of oligosaccharides and subsequent continuous ethanol fermentation was developed. The highest sugar recovery efficiency was 81.6% when concentrated sulfuric acid hydrolysis was carried out under the optimum conditions. Continuous separation of acid from the saccharified liquid after removal of color compounds with activated carbon was conducted using an improved simulated moving bed (ISMB) system, and 98.4% of sugar and 90.5% of acid were recovered. After oligosaccharide hydrolysis and pH adjustment, the unsterilized saccharified liquid was subjected to continuous ethanol fermentation using Saccharomycescerevisiae strain KF-7. The ethanol concentration, the fermentation yield based on glucose and the ethanol productivity were approximately 27.2 g/l, 92.0% and 8.2 g/l/h, respectively. These results suggest that the process is effective for production of fuel ethanol from bamboo. Copyright © 2011 Elsevier Ltd. All rights reserved.

Microbiota Dynamics Associated with Environmental Conditions and Potential Roles of Cellulolytic Communities in Traditional Chinese Cereal Starter Solid-State Fermentation

PubMed Central

Li, Pan; Liang, Hebin; Lin, Wei-Tie; Feng, Feng

2015-01-01

Traditional Chinese solid-state fermented cereal starters contain highly complex microbial communities and enzymes. Very little is known, however, about the microbial dynamics related to environmental conditions, and cellulolytic communities have never been proposed to exist during cereal starter fermentation. In this study, we performed Illumina MiSeq sequencing combined with PCR-denaturing gradient gel electrophoresis to investigate microbiota, coupled with clone library construction to trace cellulolytic communities in both fermentation stages. A succession of microbial assemblages was observed during the fermentation of starters. Lactobacillales and Saccharomycetales dominated the initial stages, with a continuous decline in relative abundance. However, thermotolerant and drought-resistant Bacillales, Eurotiales, and Mucorales were considerably accelerated during the heating stages, and these organisms dominated until the end of fermentation. Enterobacteriales were consistently ubiquitous throughout the process. For the cellulolytic communities, only the genera Sanguibacter, Beutenbergia, Agrobacterium, and Erwinia dominated the initial fermentation stages. In contrast, stages at high incubation temperature induced the appearance and dominance of Bacillus, Aspergillus, and Mucor. The enzymatic dynamics of amylase and glucoamylase also showed a similar trend, with the activities clearly increased in the first 7 days and subsequently decreased until the end of fermentation. Furthermore, β-glucosidase activity continuously and significantly increased during the fermentation process. Evidently, cellulolytic potential can adapt to environmental conditions by changes in the community structure during the fermentation of starters. PMID:26002897

Opportunities to improve the conversion of food waste to lactate: Fine-tuning secondary factors.

PubMed

RedCorn, Raymond; Engelberth, Abigail S

2017-11-01

Extensive research has demonstrated the potential for bioconversion of food waste to lactate, with major emphasis on adjusting temperature, pH, and loading rate of the fermentation. Each of these factors has a significant effect on lactate production; however, additional secondary factors have received little attention. Here we investigate three additional factors where opportunities exist for process improvement: freezing of samples during storage, discontinuous pH control, and holdover of fermentation broth between fermentations. Freezing samples prior to fermentation was shown to reduce the production rate of lactate by 8%, indicating freeze-thaw should be avoided in experiments. Prior work indicated a trade-off in pH control strategies, where discontinuous pH control correlated with higher lactate accumulation while continuous pH control correlated with higher production rate. Here we demonstrate that continuous pH control can achieve both higher lactate accumulation and higher production rate. Finally, holding over fermentation broth was shown to be a simple method to improve production rate (by 18%) at high food waste loading rates (>140 g volatile solids L -1 ) but resulted in lower lactate accumulation (by 17%). The results inform continued process improvements within the waste treatment of food waste through fermentation to lactic acid.

Application of continuous substrate feeding to the ABE fermentation: Relief of product inhibition using extraction, perstraction, stripping, and pervaporation

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

Qureshi, N.; Maddox, I.S.; Friedl, A.

1992-09-01

The technique of continuous substrate feeding has been applied to the batch fermentation process using freely suspended cells, for ABE (acetone-butanol-ethanol) production. To avoid the product inhibition which normally restricts ABE production to less than 20 g/L and sugar utilization to 60 g/L, a product removal technique has been integrated into the fermentation process. The techniques investigated were liquid-liquid extraction, perstraction, gas-stripping, and pervaporation. By using a substrate of whey permeate, the reactor productivity has been improved over that observed in a traditional batch fermentation, while equivalent lactose utilization and ABE production values of 180 g and 69 g, respectively,more » have been achieved in a 1-L culture volume. 17 refs., 14 figs., 5 tabs.« less

Efficient production of acetone-butanol-ethanol (ABE) from cassava by a fermentation-pervaporation coupled process.

PubMed

Li, Jing; Chen, Xiangrong; Qi, Benkun; Luo, Jianquan; Zhang, Yuming; Su, Yi; Wan, Yinhua

2014-10-01

Production of acetone-butanol-ethanol (ABE) from cassava was investigated with a fermentation-pervaporation (PV) coupled process. ABE products were in situ removed from fermentation broth to alleviate the toxicity of solvent to the Clostridium acetobutylicum DP217. Compared to the batch fermentation without PV, glucose consumption rate and solvent productivity increased by 15% and 21%, respectively, in batch fermentation-PV coupled process, while in continuous fermentation-PV coupled process running for 304 h, the substrate consumption rate, solvent productivity and yield increased by 58%, 81% and 15%, reaching 2.02 g/Lh, 0.76 g/Lh and 0.38 g/g, respectively. Silicalite-1 filled polydimethylsiloxane (PDMS)/polyacrylonitrile (PAN) membrane modules ensured media recycle without significant fouling, steadily generating a highly concentrated ABE solution containing 201.8 g/L ABE with 122.4 g/L butanol. After phase separation, a final product containing 574.3g/L ABE with 501.1g/L butanol was obtained. Therefore, the fermentation-PV coupled process has the potential to decrease the cost in ABE production. Copyright © 2014 Elsevier Ltd. All rights reserved.

Process engineering and scale-up of autotrophic Clostridium strain P11 syngas fermentation

NASA Astrophysics Data System (ADS)

Kundiyana, Dimple Kumar Aiyanna

Scope and Method of Study. Biomass gasification followed by fermentation of syngas to ethanol is a potential process to produce bioenergy. The process is currently being researched under laboratory- and pilot-scale in an effort to optimize the process conditions and make the process feasible for commercial production of ethanol and other biofuels such as butanol and propanol. The broad research objectives for the research were to improve ethanol yields during syngas fermentation and to design a economical fermentation process. The research included four statistically designed experimental studies in serum bottles, bench-scale and pilot-scale fermentors to screen alternate fermentation media components, to determine the effect of process parameters such as pH, temperature and buffer on syngas fermentation, to determine the effect of key limiting nutrients of the acetyl-CoA pathway in a continuous series reactor design, and to scale-up the syngas fermentation in a 100-L pilot scale fermentor. Findings and Conclusions. The first experimental study identified cotton seed extract (CSE) as a feasible medium for Clostridium strain P11 fermentation. The study showed that CSE at 0.5 g L-1 can potentially replace all the standard Clostridium strain P11 fermentation media components while using a media buffer did not significantly improve the ethanol production when used in fermentation with CSE. Scale-up of the CSE fermentation in 2-L and 5-L stirred tank fermentors showed 25% increase in ethanol yield. The second experimental study showed that syngas fermentation at 32°C without buffer was associated with higher ethanol concentration and reduced lag time in switching to solventogenesis. Conducting fermentation at 40°C or by lowering incubation pH to 5.0 resulted in reduced cell growth and no production of ethanol or acetic acid. The third experiment studied the effect of three limiting nutrients, calcium pantothenate, vitamin B12 and CoCl2 on syngas fermentation. Results indicated that it is possible to modulate the product formation by limiting key nutrients of acetyl-CoA pathway and using a continuous fermentation in two-stage fermentor design to improve ethanol yields. The last experimental study was conducted to commission a pilot scale fermentor, and subsequently scale-up the Clostridium strain P11 fermentation from a bench-scale to a pilot scale 100-L fermentor. Results indicated a six-fold improvement in ethanol concentration (25.3 g L-1 at the end of 59 d) compared to previous Clostridium strain P11 and Clostridium carboxidivorans fermentations plus the formation of other compounds such as isopropyl alcohol, acetic acid and butanol, which are of commercial importance.

Semi-Continuous Fermentation of Onion Vinegar and Its Functional Properties.

PubMed

Lee, Sulhee; Lee, Jin-A; Park, Gwi-Gun; Jang, Jae-Kweon; Park, Young-Seo

2017-08-08

For the fermentation of vinegar using onion, acetic acid bacteria and yeast strains with high fermentation ability were screened. Among them, Saccharomyces cerevisiae 1026 was selected as a starter for ethanol production and Acetobacter orientalis MAK88 was selected as a vinegar producer. When the two-stage fermentation of onion vinegar was performed at 28 °C, the titratable acidity reached 4.80% at 24 h of fermentation. When semi-continuous fermentation proceeded to charge-discharge consisting of three cycles, the acetic acid content reached 4.35% at 48 h of fermentation. At this stage, the fermentation efficiency, acetic acid productivity, and specific product formation rate were 76.71%, 17.73 g/(L·d), and 20.58 g/(g·h), respectively. The process in this study significantly reduced the fermentation time and simplified the vinegar production process. The content of total flavonoids and total polyphenols in onion vinegar were 104.36 and 455.41 μg/mL, respectively. The antioxidant activities of onion vinegar in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic) acid (ABTS⁺) radical scavenging activity, and reducing power were 75.33%, 98.88%, and 1.28, respectively. The nitrite scavenging abilities of onion vinegar were 95.38 at pH 1.2. The onion vinegar produced in this study showed higher organoleptic acceptability than commercial onion vinegar.

Effects of sodium meta bisulfite on diffusion fermentation of fodder beets for fuel ethanol production. [Saccharomyces cerevisiae

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

Gibbons, W.R.; Westby, C.A.

1987-01-01

The authors designed and tested a new process for converting fodder beets to ethanol: continuous diffusion-fermentation. This process utilizes the simultaneous diffusion-fermentation concept of the EX-FERM design; however, it overcomes the material handling problems inherent in that system by utilizing a counterflow tubular auger system. This process also eliminates the need for roller mills or presses and dryers which are required for alcohol recovery from solid phase fermentation. The latter is the only other currently feasible procedure for producing distillably worthwhile amounts of ethanol from fodder beets, sweet sorghum, and other similar feedstocks. Results on the use of sodium metamore » bisulfite (SMB) for contamination control with fermenting fodder beet cubes are reported.« less

Variation of fermentation redox potential during cell-recycling continuous ethanol operation.

PubMed

Thani, Arthit; Lin, Yen-Han; Laopaiboon, Pattana; Laopaiboon, Lakkana

2016-12-10

Fermentation redox potential was monitored during cell-recycling continuous ethanol operation. The cell-recycling system (CRS) was operated using two hollow fibre (HF) membranes (pore sizes 0.20 and 0.65μm) at three dilution rates (0.02, 0.04 and 0.08h -1 ). Saccharomyces cerevisiae NP 01 were recycled in the fermenter at a recycle ratio of 0.625. Aeration was provided at 2.5vvm for the first 4h and then further supplied continuously at 0.25vvm. As steady state was established, results showed that the fermentation redox potential was lower for processes employing CRS than those without. At the same dilution rates, the sugar utilization and ethanol production with CRS were higher than those without CRS. The highest fermentation efficiency (87.94g/l of ethanol, ∼90% of theoretical yield) was achieved using a 0.2-μm HF membrane CRS at a dilution rate of 0.02h -1 . It was found that 7.53-10.07% of the carbon derived from glucose was incorporated into the yeast. Further, at the same dilution rates, yeast in the processes with CRS incorporated less carbon into ethanol than in those grown without CRS. This result suggests that processes involving CRS utilize more carbon for metabolite synthesis than biomass formation. This indicated that the processes with CRS could utilize more carbon for metabolite synthesis than biomass formation. Copyright © 2016 Elsevier B.V. All rights reserved.

Optimization and cost estimation of novel wheat biorefining for continuous production of fermentation feedstock.

PubMed

Arifeen, Najmul; Wang, Ruohang; Kookos, Ioannis; Webb, Colin; Koutinas, Apostolis A

2007-01-01

A wheat-based continuous process for the production of a nutrient-complete feedstock for bioethanol production by yeast fermentation has been cost-optimized. This process could substitute for the current wheat dry milling process employed in industry for bioethanol production. Each major wheat component (bran, gluten, starch) is extracted and processed for different end-uses. The separate stages, liquefaction and saccharification, used currently in industry for starch hydrolysis have been integrated into a simplified continuous process by exploiting the complex enzymatic consortium produced by on-site fungal bioconversions. A process producing 120 m3 h-1 nutrient-complete feedstock for bioethanol production containing 250 g L-1 glucose and 0.85 g L-1 free amino nitrogen would result in a production cost of $0.126/kg glucose.

Microbiota Dynamics Associated with Environmental Conditions and Potential Roles of Cellulolytic Communities in Traditional Chinese Cereal Starter Solid-State Fermentation.

PubMed

Li, Pan; Liang, Hebin; Lin, Wei-Tie; Feng, Feng; Luo, Lixin

2015-08-01

Traditional Chinese solid-state fermented cereal starters contain highly complex microbial communities and enzymes. Very little is known, however, about the microbial dynamics related to environmental conditions, and cellulolytic communities have never been proposed to exist during cereal starter fermentation. In this study, we performed Illumina MiSeq sequencing combined with PCR-denaturing gradient gel electrophoresis to investigate microbiota, coupled with clone library construction to trace cellulolytic communities in both fermentation stages. A succession of microbial assemblages was observed during the fermentation of starters. Lactobacillales and Saccharomycetales dominated the initial stages, with a continuous decline in relative abundance. However, thermotolerant and drought-resistant Bacillales, Eurotiales, and Mucorales were considerably accelerated during the heating stages, and these organisms dominated until the end of fermentation. Enterobacteriales were consistently ubiquitous throughout the process. For the cellulolytic communities, only the genera Sanguibacter, Beutenbergia, Agrobacterium, and Erwinia dominated the initial fermentation stages. In contrast, stages at high incubation temperature induced the appearance and dominance of Bacillus, Aspergillus, and Mucor. The enzymatic dynamics of amylase and glucoamylase also showed a similar trend, with the activities clearly increased in the first 7 days and subsequently decreased until the end of fermentation. Furthermore, β-glucosidase activity continuously and significantly increased during the fermentation process. Evidently, cellulolytic potential can adapt to environmental conditions by changes in the community structure during the fermentation of starters. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

[Process development for continuous ethanol fermentation by the flocculating yeast under stillage backset conditions].

PubMed

Zi, Lihan; Liu, Chenguang; Bai, Fengwu

2014-02-01

Propionic acid, a major inhibitor to yeast cells, was accumulated during continuous ethanol fermentation from corn meal hydrolysate by the flocculating yeast under stillage backset conditions. Based on its inhibition mechanism in yeast cells, strategies were developed for alleviating this effect. Firstly, high temperature processes such as medium sterilization generated more propionic acid, which should be avoided. Propionic acid was reduced significantly during ethanol fermentation without medium sterilization, and concentrations of biomass and ethanol increased by 59.3% and 7.4%, respectively. Secondly, the running time of stillage backset should be controlled so that propionic acid accumulated would be lower than its half inhibition concentration IC50 (40 mmol/L). Finally, because low pH augmented propionic acid inhibition in yeast cells, a higher pH of 5.5 was validated to be suitable for ethanol fermentation under the stillage backset condition.

Coproduction of hydrogen and methane via anaerobic fermentation of cornstalk waste in continuous stirred tank reactor integrated with up-flow anaerobic sludge bed.

PubMed

Cheng, Xi-Yu; Li, Qian; Liu, Chun-Zhao

2012-06-01

A 10 L continuous stirred tank reactor (CSTR) system was developed for a two-stage hydrogen fermentation process with an integrated alkaline treatment. The maximum hydrogen production rate reached 218.5 mL/L h at a cornstalk concentration of 30 g/L, and the total hydrogen yield and volumetric hydrogen production rate reached 58.0 mL/g-cornstalk and 0.55-0.57 L/L d, respectively. A 10 L up-flow anaerobic sludge bed (UASB) was used for continuous methane fermentation of the effluents obtained from the two-stage hydrogen fermentation. At the optimal organic loading rate of 15.0 g-COD/Ld, the COD removal efficiency and volumetric biogas production rate reached 83.3% and 4.6L/Ld, respectively. Total methane yield reached 200.9 mL/g-cornstalk in anaerobic fermentation with the effluents and alkaline hydrolysate. As a result, the total energy recovery by coproduction of hydrogen and methane with anaerobic fermentation of cornstalk reached 67.1%. Copyright © 2012 Elsevier Ltd. All rights reserved.

Plasmid fermentation process for DNA immunization applications.

PubMed

Carnes, Aaron E; Williams, James A

2014-01-01

Plasmid DNA for immunization applications must be of the highest purity and quality. The ability of downstream purification to efficiently produce a pure final product is directly influenced by the performance of the upstream fermentation process. While several clinical manufacturing facilities already have validated fermentation processes in place to manufacture plasmid DNA for use in humans, a simple and inexpensive laboratory-scale fermentation process can be valuable for in-house production of plasmid DNA for use in animal efficacy studies. This chapter describes a simple fed-batch fermentation process for producing bacterial cell paste enriched with high-quality plasmid DNA. A constant feeding strategy results in a medium cell density culture with continuously increasing plasmid amplification towards the end of the process. Cell banking and seed culture preparation protocols, which can dramatically influence final product yield and quality, are also described. These protocols are suitable for production of research-grade plasmid DNA at the 100 mg-to-1.5 g scale from a typical 10 L laboratory benchtop fermentor.

Continuous beer fermentation using immobilized yeast cell bioreactor systems.

PubMed

Brányik, Tomás; Vicente, António A; Dostálek, Pavel; Teixeira, José A

2005-01-01

Traditional beer fermentation and maturation processes use open fermentation and lager tanks. Although these vessels had previously been considered indispensable, during the past decades they were in many breweries replaced by large production units (cylindroconical tanks). These have proved to be successful, both providing operating advantages and ensuring the quality of the final beer. Another promising contemporary technology, namely, continuous beer fermentation using immobilized brewing yeast, by contrast, has found only a limited number of industrial applications. Continuous fermentation systems based on immobilized cell technology, albeit initially successful, were condemned to failure for several reasons. These include engineering problems (excess biomass and problems with CO(2) removal, optimization of operating conditions, clogging and channeling of the reactor), unbalanced beer flavor (altered cell physiology, cell aging), and unrealized cost advantages (carrier price, complex and unstable operation). However, recent development in reactor design and understanding of immobilized cell physiology, together with application of novel carrier materials, could provide a new stimulus to both research and application of this promising technology.

Development of a more efficient process for production of fuel ethanol from bamboo.

PubMed

Sun, Zhao-Yong; Wang, Ting; Tan, Li; Tang, Yue-Qin; Kida, Kenji

2015-06-01

A process for production of fuel ethanol from bamboo treated with concentrated sulfuric acid has been previously proposed. To improve efficiency of the process, we tested saccharification with 70 weight% (wt%) sulfuric acid, acid-sugar separation by ion exclusion, addition of nutrients to the ethanol fermentation, and bioconversion of xylose to xylitol. A high efficiency of both sugar recovery (82.5 %) and acid recovery (97.5 %) was achieved in the saccharification process and in the continuous acid-sugar separation using a modified anion exchange resin, respectively. Reduction of the amount of mineral salts added to the saccharified liquid after acid-sugar separation did not negatively affect performance of the continuous ethanol fermentation. The ethanol yield and productivity were 93.7 % and 6 g/l h, respectively, at 35 °C and pH 4.0. And the ethanol yield and productivity were almost the same even at pH 3.5. Moreover, the xylose remaining in the fermented mash was efficiently converted to xylitol in batch fermentation by Candida tropicalis strain 2.1776. These results demonstrate a more efficient process for the production of fuel ethanol from bamboo.

Biological decolourisation of wastewater from molasses fermentation by Trametes versicolor in an airlift reactor.

PubMed

Rioja, R; García, M T; Peña, M; González, G

2008-06-01

Continuous decolourisation of wastewater from molasses fermentation using mycelium of Trametes versicolor in pellets shape was performed in an airlift bioreactor (semi-pilot scale) with the aim of operating steadily for a long period, maintaining the colour removal activity. The influences of influent flow and glucose feed rate were tested. Induction of peroxidases secretion by Mn(2+) addition was also studied. The efficiency of the decolourisation process was followed by monitoring colour and enzymatic activities. The experimental results showed that continuous decolourisation in an airlift bioreactor can be considered a suitable alternative for treating molasses fermentation wastewater. A colour removal yield around 60% remained practically constant during 23 days under continuous operation. Laccase was found to be the main enzyme secreted by the strain, being responsible for the decolourisation process. Mn(2+) addition was not likely to induct manganese-dependent peroxidase secretion.

Efficient arachidonic acid-rich oil production by Mortierella alpina through a repeated fed-batch fermentation strategy.

PubMed

Ji, Xiao-Jun; Zhang, Ai-Hui; Nie, Zhi-Kui; Wu, Wen-Jia; Ren, Lu-Jing; Huang, He

2014-10-01

Arachidonic acid (ARA)-rich oil production by Mortierella alpina is a long fermentation period needed process due to the low growth rate of the filamentous fungus used. This causes the low productivity of ARA-rich oil and hinders its industrial mass scale production. In the present study, different fed-batch strategies were conducted to shorten the fermentation period. The result showed that compared with the batch culture, the fermentation period was shortened from 7days to 5days with the productivity of ARA-rich oil increased from 0.9g/(L·d) to 1.3g/(L·d) by using the fed-batch fermentation strategy. Furthermore, repeated fed-batch fermentation strategy was adopted to achieve the purpose of continuous production. By using this strategy, the fermentation period was shortened from 40days to 26days in a four cycle repeated fed-batch fermentation. This strategy proved to be convenient and economical for ARA-rich oil commercial production process. Copyright © 2014 Elsevier Ltd. All rights reserved.

Troubleshooting fermentation in corn wet milling ethanol production

USDA-ARS?s Scientific Manuscript database

To convert starch to ethanol, continuous fermentation processes are employed by corn wet milling plants all over world. Contaminations by bacterial microorganisms like Lactobacillus and wild yeasts like Brettanomyces are common and result in lower ethanol yields (Abbott and Ingledew 2005, Skinner an...

Restructuring upstream bioprocessing: technological and economical aspects for production of a generic microbial feedstock from wheat.

PubMed

Koutinas, A A; Wang, R; Webb, C

2004-03-05

Restructuring and optimization of the conventional fermentation industry for fuel and chemical production is necessary to replace petrochemical production routes. Guided by this concept, a novel biorefinery process has been developed as an alternative to conventional upstream processing routes, leading to the production of a generic fermentation feedstock from wheat. The robustness of Aspergillus awamori as enzyme producer is exploited in a continuous fungal fermentation on whole wheat flour. Vital gluten is extracted as an added-value byproduct by the conventional Martin process from a fraction of the overall wheat used. Enzymatic hydrolysis of gluten-free flour by the enzyme complex produced by A. awamori during fermentation produces a liquid stream rich in glucose (320 g/L). Autolysis of fungal cells produces a micronutrient-rich solution similar to yeast extract (1.6 g/L nitrogen, 0.5 g/L phosphorus). The case-specific combination of these two liquid streams can provide a nutrient-complete fermentation medium for a spectrum of microbial bioconversions for the production of such chemicals as organic acids, amino acids, bioethanol, glycerol, solvents, and microbial biodegradable plastics. Preliminary economic analysis has shown that the operating cost required to produce the feedstock is dependent on the plant capacity, cereal market price, presence and market value of added-value byproducts, labor costs, and mode of processing (batch or continuous). Integration of this process in an existing fermentation plant could lead to the production of a generic feedstock at an operating cost lower than the market price of glucose syrup (90% to 99% glucose) in the EU, provided that the plant capacity exceeds 410 m(3)/day. Further process improvements are also suggested. Copyright 2004 Wiley Periodicals, Inc.

Comparative technoeconomic analysis of a softwood ethanol process featuring posthydrolysis sugars concentration operations and continuous fermentation with cell recycle.

PubMed

Schneiderman, Steven J; Gurram, Raghu N; Menkhaus, Todd J; Gilcrease, Patrick C

2015-01-01

Economical production of second generation ethanol from Ponderosa pine is of interest due to widespread mountain pine beetle infestation in the western United States and Canada. The conversion process is limited by low glucose and high inhibitor concentrations resulting from conventional low-solids dilute acid pretreatment and enzymatic hydrolysis. Inhibited fermentations require larger fermentors (due to reduced volumetric productivity) and low sugars lead to low ethanol titers, increasing distillation costs. In this work, multiple effect evaporation (MEE) and nanofiltration (NF) were evaluated to concentrate the hydrolysate from 30 g/l to 100, 150, or 200 g/l glucose. To ferment this high gravity, inhibitor containing stream, traditional batch fermentation was compared with continuous stirred tank fermentation (CSTF) and continuous fermentation with cell recycle (CSTF-CR). Equivalent annual operating cost (EAOC = amortized capital + yearly operating expenses) was used to compare these potential improvements for a local-scale 5 MGY ethanol production facility. Hydrolysate concentration via evaporation increased EAOC over the base process due to the capital and energy intensive nature of evaporating a very dilute sugar stream; however, concentration via NF decreased EAOC for several of the cases (by 2 to 15%). NF concentration to 100 g/l glucose with a CSTF-CR was the most economical option, reducing EAOC by $0.15 per gallon ethanol produced. Sensitivity analyses on NF options showed that EAOC improvement over the base case could still be realized for even higher solids removal requirements (up to two times higher centrifuge requirement for the best case) or decreased NF performance. © 2015 American Institute of Chemical Engineers.

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

PubMed

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

2016-03-01

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

Bioethanol production from fermentable sugar juice.

PubMed

Zabed, Hossain; Faruq, Golam; Sahu, Jaya Narayan; Azirun, Mohd Sofian; Hashim, Rosli; Boyce, Amru Nasrulhaq

2014-01-01

Bioethanol production from renewable sources to be used in transportation is now an increasing demand worldwide due to continuous depletion of fossil fuels, economic and political crises, and growing concern on environmental safety. Mainly, three types of raw materials, that is, sugar juice, starchy crops, and lignocellulosic materials, are being used for this purpose. This paper will investigate ethanol production from free sugar containing juices obtained from some energy crops such as sugarcane, sugar beet, and sweet sorghum that are the most attractive choice because of their cost-effectiveness and feasibility to use. Three types of fermentation process (batch, fed-batch, and continuous) are employed in ethanol production from these sugar juices. The most common microorganism used in fermentation from its history is the yeast, especially, Saccharomyces cerevisiae, though the bacterial species Zymomonas mobilis is also potentially used nowadays for this purpose. A number of factors related to the fermentation greatly influences the process and their optimization is the key point for efficient ethanol production from these feedstocks.

Bioethanol Production from Fermentable Sugar Juice

PubMed Central

Zabed, Hossain; Faruq, Golam; Sahu, Jaya Narayan; Azirun, Mohd Sofian; Hashim, Rosli; Nasrulhaq Boyce, Amru

2014-01-01

Bioethanol production from renewable sources to be used in transportation is now an increasing demand worldwide due to continuous depletion of fossil fuels, economic and political crises, and growing concern on environmental safety. Mainly, three types of raw materials, that is, sugar juice, starchy crops, and lignocellulosic materials, are being used for this purpose. This paper will investigate ethanol production from free sugar containing juices obtained from some energy crops such as sugarcane, sugar beet, and sweet sorghum that are the most attractive choice because of their cost-effectiveness and feasibility to use. Three types of fermentation process (batch, fed-batch, and continuous) are employed in ethanol production from these sugar juices. The most common microorganism used in fermentation from its history is the yeast, especially, Saccharomyces cerevisiae, though the bacterial species Zymomonas mobilis is also potentially used nowadays for this purpose. A number of factors related to the fermentation greatly influences the process and their optimization is the key point for efficient ethanol production from these feedstocks. PMID:24715820

Improved fermentation performance in an expanded ectopic fermentation system inoculated with thermophilic bacteria.

PubMed

Guo, Hui; Zhu, Changxiong; Geng, Bing; Liu, Xue; Ye, Jing; Tian, Yunlong; Peng, Xiawei

2015-12-01

Previous research showed that ectopic fermentation system (EFS) inoculated with thermophilic bacteria is an excellent alternative for cow wastewater treatment. In this study, the effects of thermophilic bacterial consortium on the efficiency and quality of the fermentation process in EFS were evaluated by measuring physicochemical and environmental factors and the changes in organic matter composition. In parallel, the microbial communities correlated with fermentation performance were identified. Inoculation of EFS with thermophilic bacterial consortium led to higher temperatures, increased wastewater requirements for continuous fermentation, and improved quality of the litters in terms of physicochemical factors, security test, functional group analysis, and bacterial community composition. The relationship between the transformation of organic component and the dominant bacteria species indicated that environmental factors contributed to strain growth, which subsequently promoted the fermentation process. The results highlight the great potential of EFS model for wide application in cow wastewater treatment and re-utilization as bio-fertilizer. Copyright © 2015 Elsevier Ltd. All rights reserved.

Source tracking of prokaryotic communities in fermented grain of Chinese strong-flavor liquor.

PubMed

Wang, Xueshan; Du, Hai; Xu, Yan

2017-03-06

The fermentation process of Chinese strong-flavor liquor involves numerous microbes originating from Daqu and pit mud. Daqu is the starter of fermentation, and pit mud acts as another source of inoculum of microbes in the liquor-making process. However, the contribution of microbes in pit mud and Daqu to fermented grain, and the sources of microbes in fermented grain are still waiting to be defined clearly. In this study, prokaryotic communities in fermented grain, pit mud and Daqu were identified via next generation sequencing of the V4 region of 16S rRNA gene. Principal-coordinate analysis indicated that Daqu had stronger influence on the prokaryotic communities in fermented grain at the prophase of fermentation, but pit mud influenced the fermented grain continuously during the whole fermentation process. Totally, 299 genera were detected in all fermented grain, pit mud and Daqu samples. Among them, 204 genera were detected in 3days' fermented grain. Ten genera (Lactobacillus, Leuconostoc, Staphylococcus, Gluconobacter, Acetobacter, Petrimonas, Clostridium, Ruminococcus, Methanobacterium and Methanobrevibacter) were dominant, and accounted for 84.31%-87.13% relative abundance of the total prokaryotic community in fermented grain. Venn analysis indicated Daqu was the main source of strict aerobes and facultative aerobes, which took up over 74% of prokaryotic communities in fermented grain. Conversely, pit mud was the sustained-release source of anaerobes, which accounted for over 14% of prokaryotic communities in fermented grain. In addition, part of anaerobes originated from both Daqu and pit mud. This study could help track the source of prokaryotic communities in fermented grain, and improve the quality and controllability in liquor production. Copyright © 2017 Elsevier B.V. All rights reserved.

High ethanol producing derivatives of Thermoanaerobacter ethanolicus

DOEpatents

Ljungdahl, L.G.; Carriera, L.H.

1983-05-24

Derivatives of the newly discovered microorganism Thermoanaerobacter ethanolicus which under anaerobic and thermophilic conditions continuously ferment substrates such as starch, cellobiose, glucose, xylose and other sugars to produce recoverable amounts of ethanol solving the problem of fermentations yielding low concentrations of ethanol using the parent strain of the microorganism Thermoanaerobacter ethanolicus are disclosed. These new derivatives are ethanol tolerant up to 10% (v/v) ethanol during fermentation. The process includes the use of an aqueous fermentation medium, containing the substrate at a substrate concentration greater than 1% (w/v).

High ethanol producing derivatives of Thermoanaerobacter ethanolicus

DOEpatents

Ljungdahl, Lars G.; Carriera, Laura H.

1983-01-01

Derivatives of the newly discovered microorganism Thermoanaerobacter ethanolicus which under anaerobic and thermophilic conditions continuously ferment substrates such as starch, cellobiose, glucose, xylose and other sugars to produce recoverable amounts of ethanol solving the problem of fermentations yielding low concentrations of ethanol using the parent strain of the microorganism Thermoanaerobacter ethanolicus are disclosed. These new derivatives are ethanol tolerant up to 10% (v/v) ethanol during fermentation. The process includes the use of an aqueous fermentation medium, containing the substrate at a substrate concentration greater than 1% (w/v).

Applied in situ product recovery in ABE fermentation

PubMed Central

Lalander, Carl‐Axel; Lee, Jonathan G. M.; Davies, E. Timothy; Harvey, Adam P.

2017-01-01

The production of biobutanol is hindered by the product's toxicity to the bacteria, which limits the productivity of the process. In situ product recovery of butanol can improve the productivity by removing the source of inhibition. This paper reviews in situ product recovery techniques applied to the acetone butanol ethanol fermentation in a stirred tank reactor. Methods of in situ recovery include gas stripping, vacuum fermentation, pervaporation, liquid–liquid extraction, perstraction, and adsorption, all of which have been investigated for the acetone, butanol, and ethanol fermentation. All techniques have shown an improvement in substrate utilization, yield, productivity or both. Different fermentation modes favored different techniques. For batch processing gas stripping and pervaporation were most favorable, but in fed‐batch fermentations gas stripping and adsorption were most promising. During continuous processing perstraction appeared to offer the best improvement. The use of hybrid techniques can increase the final product concentration beyond that of single‐stage techniques. Therefore, the selection of an in situ product recovery technique would require comparable information on the energy demand and economics of the process. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:563–579, 2017 PMID:28188696

Vapor-fed bio-hybrid fuel cell.

PubMed

Benyamin, Marcus S; Jahnke, Justin P; Mackie, David M

2017-01-01

Concentration and purification of ethanol and other biofuels from fermentations are energy-intensive processes, with amplified costs at smaller scales. To circumvent the need for these processes, and to potentially reduce transportation costs as well, we have previously investigated bio-hybrid fuel cells (FCs), in which a fermentation and FC are closely coupled. However, long-term operation requires strictly preventing the fermentation and FC from harming each other. We introduce here the concept of the vapor-fed bio-hybrid FC as a means of continuously extracting power from ongoing fermentations at ambient conditions. By bubbling a carrier gas (N 2 ) through a yeast fermentation and then through a direct ethanol FC, we protect the FC anode from the catalyst poisons in the fermentation (which are non-volatile), and also protect the yeast from harmful FC products (notably acetic acid) and from build-up of ethanol. Since vapor-fed direct ethanol FCs at ambient conditions have never been systematically characterized (in contrast to vapor-fed direct methanol FCs), we first assess the effects on output power and conversion efficiency of ethanol concentration, vapor flow rate, and FC voltage. The results fit a continuous stirred-tank reactor model. Over a wide range of ethanol partial pressures (2-8 mmHg), power densities are comparable to those for liquid-fed direct ethanol FCs at the same temperature, with power densities >2 mW/cm 2 obtained. We then demonstrate the continuous operation of a vapor-fed bio-hybrid FC with fermentation for 5 months, with no indication of performance degradation due to poisoning (of either the FC or the fermentation). It is further shown that the system is stable, recovering quickly from disturbances or from interruptions in maintenance. The vapor-fed bio-hybrid FC enables extraction of power from dilute bio-ethanol streams without costly concentration and purification steps. The concept should be scalable to both large and small operations and should be generalizable to other biofuels and waste-to-energy systems.

Effective multiple stages continuous acetone-butanol-ethanol fermentation by immobilized bioreactors: Making full use of fresh corn stalk.

PubMed

Chang, Zhen; Cai, Di; Wang, Yong; Chen, Changjing; Fu, Chaohui; Wang, Guoqing; Qin, Peiyong; Wang, Zheng; Tan, Tianwei

2016-04-01

In order to make full use of the fresh corn stalk, the sugar containing juice was used as the sole substrate for acetone-butanol-ethanol production without any nutrients supplement, and the bagasse after squeezing the juice was used as the immobilized carrier. A total 21.34g/L of ABE was produced in batch cells immobilization system with ABE yield of 0.35g/g. A continuous fermentation containing three stages with immobilized cells was conducted and the effect of dilution rate on fermentation was investigated. As a result, the productivity and ABE solvents concentration reached 0.80g/Lh and 19.93g/L, respectively, when the dilution rate in each stage was 0.12/h (corresponding to a dilution rate of 0.04/h in the whole system). And the long-term operation indicated the continuous multiple stages ABE fermentation process had good stability and showed the great potential in future industrial applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

A new strategy of glucose supply in a microbial fermentation model

NASA Astrophysics Data System (ADS)

Kasbawati, Gunawan, A. Y.; Sidarto, K. A.; Hertadi, R.

2015-09-01

Strategy of glucose supply to achieve an optimal productivity of ethanol production of a yeast cell is one of the main features in a microbial fermentation process. Beside a known continuous glucose supply, in this study we consider a new supply strategy so called the on-off supply. An optimal control theory is applied to the fermentation system to find the optimal rate of glucose supply and time of supply. The optimization problem is solved numerically using Differential Evolutionary algorithm. We find two alternative solutions that we can choose to get the similar result: either long period process with low supply or short period process with high glucose supply.

Lysine Fermentation: History and Genome Breeding.

PubMed

Ikeda, Masato

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

Fermentation of Saccharomyces cerevisiae - Combining kinetic modeling and optimization techniques points out avenues to effective process design.

PubMed

Scheiblauer, Johannes; Scheiner, Stefan; Joksch, Martin; Kavsek, Barbara

2018-09-14

A combined experimental/theoretical approach is presented, for improving the predictability of Saccharomyces cerevisiae fermentations. In particular, a mathematical model was developed explicitly taking into account the main mechanisms of the fermentation process, allowing for continuous computation of key process variables, including the biomass concentration and the respiratory quotient (RQ). For model calibration and experimental validation, batch and fed-batch fermentations were carried out. Comparison of the model-predicted biomass concentrations and RQ developments with the corresponding experimentally recorded values shows a remarkably good agreement for both batch and fed-batch processes, confirming the adequacy of the model. Furthermore, sensitivity studies were performed, in order to identify model parameters whose variations have significant effects on the model predictions: our model responds with significant sensitivity to the variations of only six parameters. These studies provide a valuable basis for model reduction, as also demonstrated in this paper. Finally, optimization-based parametric studies demonstrate how our model can be utilized for improving the efficiency of Saccharomyces cerevisiae fermentations. Copyright © 2018 Elsevier Ltd. All rights reserved.

Bioproduction of butanol in bioreactors: new insights from simultaneous in situ butanol recovery to eliminate product toxicity

USDA-ARS?s Scientific Manuscript database

Simultaneous acetone butanol ethanol (ABE) fermentation by Clostridium beijerinckii 260 and in situ product recovery was investigated using a vacuum process operated in two modes: continuous and intermittent. Integrated batch fermentations and ABE recovery were conducted at 37 deg C using a 14-L bio...

Optimisation of continuous gas fermentation by immobilisation of acetate-producing Acetobacterium woodii.

PubMed

Steger, Franziska; Rachbauer, Lydia; Windhagauer, Matthias; Montgomery, Lucy F R; Bochmann, Günther

2017-08-01

Hydrogen from water electrolysis is often suggested as a way of storing the excess energy from wind and solar power plants. However, unlike natural gas, hydrogen is difficult to store and distribute. One solution is to convert the hydrogen into other fuels or bulk chemicals. In this study we investigated fermentation in which homoacetogenic clostridia apply the Wood-Ljungdahl pathway to generate acetate from H 2 and CO 2 . Acetate can be used as a bulk chemical or further transformed into biofuels. Autotrophic growth with CO 2 as the sole carbon source is slow compared to heterotrophic growth, so the aim of this work was to improve continuous gas fermentation by immobilising the acetate-producing clostridia, thus preventing their wash out from the bioreactor. Two homoacetogenic bacterial strains (Acetobacterium woodii and Moorella thermoacetica) were tested for their acetate production potential, with A. woodii proving to be the better strain with maximum acetate concentration of 29.57 g l -1 . Due to its stability during fermentation and good bacterial immobilisation, linen was chosen as immobilisation material for continuous fermentation. This study demonstrates the successful continuous fermentation of acetate from H 2 and CO 2 using A. woodii immobilised on a low-cost surface at high volumetric productivity of 1.21 ± 0.05 g acetate l -1 d -1 . This has great industrial potential and future studies should focus on the scale-up of this process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Acetone-butanol-ethanol (ABE) fermentation using Clostridium acetobutylicum XY16 and in situ recovery by PDMS/ceramic composite membrane.

PubMed

Wu, Hao; Chen, Xiao-Peng; Liu, Gong-Ping; Jiang, Min; Guo, Ting; Jin, Wan-Qin; Wei, Ping; Zhu, Da-Wei

2012-09-01

PDMS/ceramic composite membrane was directly integrated with acetone-butanol-ethanol (ABE) fermentation using Clostridium acetobutylicum XY16 at 37 °C and in situ removing ABE from fermentation broth. The membrane was integrated with batch fermentation, and approximately 46 % solvent was extracted. The solvent in permeates was 118 g/L, and solvent productivity was 0.303 g/(L/h), which was approximately 33 % higher compared with the batch fermentation without in situ recovery. The fed-batch fermentation with in situ recovery by pervaporation continued for more than 200 h, 61 % solvent was extracted, and the solvent in penetration was 96.2 g/L. The total flux ranged from 0.338 to 0.847 kg/(m(2)/h) and the separation factor of butanol ranged from 5.1 to 27.1 in this process. The membrane was fouled by the active fermentation broth, nevertheless the separation performances were partially recovered by offline membrane cleaning, and the solvent productivity was increased to 0.252 g/(L/h), which was 19 % higher compared with that in situ recovery process without membrane cleaning.

Diffusion-driven proton exchange membrane fuel cell for converting fermenting biomass to electricity.

PubMed

Malati, P; Mehrotra, P; Minoofar, P; Mackie, D M; Sumner, J J; Ganguli, R

2015-10-01

A membrane-integrated proton exchange membrane fuel cell that enables in situ fermentation of sugar to ethanol, diffusion-driven separation of ethanol, and its catalytic oxidation in a single continuous process is reported. The fuel cell consists of a fermentation chamber coupled to a direct ethanol fuel cell. The anode and fermentation chambers are separated by a reverse osmosis (RO) membrane. Ethanol generated from fermented biomass in the fermentation chamber diffuses through the RO membrane into a glucose solution contained in the DEFC anode chamber. The glucose solution is osmotically neutral to the biomass solution in the fermentation chamber preventing the anode chamber from drying out. The fuel cell sustains >1.3 mW cm(-2) at 47°C with high discharge capacity. No separate purification or dilution is necessary, resulting in an efficient and portable system for direct conversion of fermenting biomass to electricity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of a semi-continuous two-stage simultaneous saccharification and fermentation process for enhanced 2,3-butanediol production by Klebsiella oxytoca.

PubMed

Moon, S-K; Kim, D-K; Park, J M; Min, J; Song, H

2018-04-01

Klebsiella oxytoca naturally produces a large amount of 2,3-butanediol (2,3-BD), a promising chemical with wide industrial applications, along with various by-products. Previously, we have developed a metabolically engineered K. oxytoca ΔldhA ΔpflB strain to reduce the formation of by-products. To improve 2,3-BD productivity and examine the stability of K. oxytoca ΔldhA ΔpflB strain for industrial application, a semi-continuous two-stage simultaneous saccharification and fermentation (STSSF) process was developed. The STSSF with the K. oxytoca ΔldhA ΔpflB mutant using cassava as a carbon source could produce 108 ± 3·73 g (2,3- BD )  l -1 with a yield of 0·45 g (2,3- BD )  g (glucose) -1 and a productivity of 3·00 g (2,3- BD ) l -1  h -1 . No apparent changes in the final titre, yield and productivity of 2,3-BD were observed for up to 20 cycles of STSSF. Also, microbial contamination and spontaneous mutation of the host strain with potential detrimental effects on fermentation efficiency did not occur during the whole fermentation period. These results strongly underpin that the K. oxytoca ΔldhA ΔpflB mutant is stable and that the STSSF process is commercially exploitable. There is growing interest in the production of 2,3-butanediol (2,3-BD) from renewable resources by microbial fermentation because of its wide applications to specialty and commodity chemical industries. Klebsiella oxytoca usually produces 2,3-BD as a major end product during the fermentation of carbohydrates. This is the first study to provide a high-efficiency simultaneous saccharification and 2,3-BD fermentation process. Also, this study proves the stability of a metabolically engineered 2,3-BD overproducing K. oxytoca strain for industrial application. © 2018 The Society for Applied Microbiology.

Optimization strategies based on sequential quadratic programming applied for a fermentation process for butanol production.

PubMed

Pinto Mariano, Adriano; Bastos Borba Costa, Caliane; de Franceschi de Angelis, Dejanira; Maugeri Filho, Francisco; Pires Atala, Daniel Ibraim; Wolf Maciel, Maria Regina; Maciel Filho, Rubens

2009-11-01

In this work, the mathematical optimization of a continuous flash fermentation process for the production of biobutanol was studied. The process consists of three interconnected units, as follows: fermentor, cell-retention system (tangential microfiltration), and vacuum flash vessel (responsible for the continuous recovery of butanol from the broth). The objective of the optimization was to maximize butanol productivity for a desired substrate conversion. Two strategies were compared for the optimization of the process. In one of them, the process was represented by a deterministic model with kinetic parameters determined experimentally and, in the other, by a statistical model obtained using the factorial design technique combined with simulation. For both strategies, the problem was written as a nonlinear programming problem and was solved with the sequential quadratic programming technique. The results showed that despite the very similar solutions obtained with both strategies, the problems found with the strategy using the deterministic model, such as lack of convergence and high computational time, make the use of the optimization strategy with the statistical model, which showed to be robust and fast, more suitable for the flash fermentation process, being recommended for real-time applications coupling optimization and control.

Utilization of cellulosic materials through enzyamtic hydrolysis. I. Fermentation of hydrolysate to ethanol and single-cell protein.

PubMed

Cysewski, G R; Wilke, C R

1976-09-01

Ethanol fermentation studies were conducted with Saccharomyces cerevisiae ATCC "4126, to determine the optimal conditions of oxygen tension and feed sugar concentration. In long-term continuous culture maximum ethanol production was found to occur at 0.07 mmHg oxygen tension and 10% glucose feed concentration. Preliminary process design and cost studies are developed for industrial scale fermentations to produce ethanol and torula yeast from sugars obtained by enzymatic hydrolysis of newsprint.

Continuous Cellulosic Bioethanol Fermentation by Cyclic Fed-Batch Cocultivation

PubMed Central

Jiang, He-Long; He, Qiang; He, Zhili; Hemme, Christopher L.; Wu, Liyou

2013-01-01

Cocultivation of cellulolytic and saccharolytic microbial populations is a promising strategy to improve bioethanol production from the fermentation of recalcitrant cellulosic materials. Earlier studies have demonstrated the effectiveness of cocultivation in enhancing ethanolic fermentation of cellulose in batch fermentation. To further enhance process efficiency, a semicontinuous cyclic fed-batch fermentor configuration was evaluated for its potential in enhancing the efficiency of cellulose fermentation using cocultivation. Cocultures of cellulolytic Clostridium thermocellum LQRI and saccharolytic Thermoanaerobacter pseudethanolicus strain X514 were tested in the semicontinuous fermentor as a model system. Initial cellulose concentration and pH were identified as the key process parameters controlling cellulose fermentation performance in the fixed-volume cyclic fed-batch coculture system. At an initial cellulose concentration of 40 g liter−1, the concentration of ethanol produced with pH control was 4.5-fold higher than that without pH control. It was also found that efficient cellulosic bioethanol production by cocultivation was sustained in the semicontinuous configuration, with bioethanol production reaching 474 mM in 96 h with an initial cellulose concentration of 80 g liter−1 and pH controlled at 6.5 to 6.8. These results suggested the advantages of the cyclic fed-batch process for cellulosic bioethanol fermentation by the cocultures. PMID:23275517

Additive Manufacturing of Catalytically Active Living Materials.

PubMed

Saha, Abhijit; Johnston, Trevor G; Shafranek, Ryan T; Goodman, Cassandra J; Zalatan, Jesse G; Storti, Duane W; Ganter, Mark A; Nelson, Alshakim

2018-04-25

Living materials, which are composites of living cells residing in a polymeric matrix, are designed to utilize the innate functionalities of the cells to address a broad range of applications such as fermentation and biosensing. Herein, we demonstrate the additive manufacturing of catalytically active living materials (AMCALM) for continuous fermentation. A multi-stimuli-responsive yeast-laden hydrogel ink, based on F127-dimethacrylate, was developed and printed using a direct-write 3D printer. The reversible stimuli-responsive behaviors of the polymer hydrogel inks to temperature and pressure are critical, as they enabled the facile incorporation of yeast cells and subsequent fabrication of 3D lattice constructs. Subsequent photo-cross-linking of the printed polymer hydrogel afforded a robust elastic material. These yeast-laden living materials were metabolically active in the fermentation of glucose into ethanol for 2 weeks in a continuous batch process without significant reduction in efficiency (∼90% yield of ethanol). This cell immobilization platform may potentially be applicable toward other genetically modified yeast strains to produce other high-value chemicals in a continuous biofermentation process.

Online monitoring of Mezcal fermentation based on redox potential measurements.

PubMed

Escalante-Minakata, P; Ibarra-Junquera, V; Rosu, H C; De León-Rodríguez, A; González-García, R

2009-01-01

We describe an algorithm for the continuous monitoring of the biomass and ethanol concentrations as well as the growth rate in the Mezcal fermentation process. The algorithm performs its task having available only the online measurements of the redox potential. The procedure combines an artificial neural network (ANN) that relates the redox potential to the ethanol and biomass concentrations with a nonlinear observer-based algorithm that uses the ANN biomass estimations to infer the growth rate of this fermentation process. The results show that the redox potential is a valuable indicator of the metabolic activity of the microorganisms during Mezcal fermentation. In addition, the estimated growth rate can be considered as a direct evidence of the presence of mixed culture growth in the process. Usually, mixtures of microorganisms could be intuitively clear in this kind of processes; however, the total biomass data do not provide definite evidence by themselves. In this paper, the detailed design of the software sensor as well as its experimental application is presented at the laboratory level.

Applied in situ product recovery in ABE fermentation.

PubMed

Outram, Victoria; Lalander, Carl-Axel; Lee, Jonathan G M; Davies, E Timothy; Harvey, Adam P

2017-05-01

The production of biobutanol is hindered by the product's toxicity to the bacteria, which limits the productivity of the process. In situ product recovery of butanol can improve the productivity by removing the source of inhibition. This paper reviews in situ product recovery techniques applied to the acetone butanol ethanol fermentation in a stirred tank reactor. Methods of in situ recovery include gas stripping, vacuum fermentation, pervaporation, liquid-liquid extraction, perstraction, and adsorption, all of which have been investigated for the acetone, butanol, and ethanol fermentation. All techniques have shown an improvement in substrate utilization, yield, productivity or both. Different fermentation modes favored different techniques. For batch processing gas stripping and pervaporation were most favorable, but in fed-batch fermentations gas stripping and adsorption were most promising. During continuous processing perstraction appeared to offer the best improvement. The use of hybrid techniques can increase the final product concentration beyond that of single-stage techniques. Therefore, the selection of an in situ product recovery technique would require comparable information on the energy demand and economics of the process. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:563-579, 2017. © 2017 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers.

Creating Economic Incentives for Waste Disposal in Developing Countries Using the MixAlco Process.

PubMed

Lonkar, Sagar; Fu, Zhihong; Wales, Melinda; Holtzapple, Mark

2017-01-01

In rapidly growing developing countries, waste disposal is a major challenge. Current waste disposal methods (e.g., landfills and sewage treatment) incur costs and often are not employed; thus, wastes accumulate in the environment. To address this challenge, it is advantageous to create economic incentives to collect and process wastes. One approach is the MixAlco process, which uses methane-inhibited anaerobic fermentation to convert waste biomass into carboxylate salts, which are chemically converted to industrial chemicals and fuels. In this paper, humanure (raw human feces and urine) is explored as a possible nutrient source for fermentation. This work focuses on fermenting municipal solid waste (energy source) and humanure (nutrient source) in batch fermentations. Using the Continuum Particle Distribution Model (CPDM), the performance of continuous countercurrent fermentation was predicted at different volatile solid loading rates (VSLR) and liquid residence times (LRT). For a four-stage countercurrent fermentation system at VSLR = 4 g/(L∙day), LRT = 30 days, and solids concentration = 100 g/L liquid, the model predicts carboxylic acid concentration of 68 g/L and conversion of 78.5 %.

Kinetic Study of Acetone-Butanol-Ethanol Fermentation in Continuous Culture

PubMed Central

Buehler, Edward A.; Mesbah, Ali

2016-01-01

Acetone-butanol-ethanol (ABE) fermentation by clostridia has shown promise for industrial-scale production of biobutanol. However, the continuous ABE fermentation suffers from low product yield, titer, and productivity. Systems analysis of the continuous ABE fermentation will offer insights into its metabolic pathway as well as into optimal fermentation design and operation. For the ABE fermentation in continuous Clostridium acetobutylicum culture, this paper presents a kinetic model that includes the effects of key metabolic intermediates and enzymes as well as culture pH, product inhibition, and glucose inhibition. The kinetic model is used for elucidating the behavior of the ABE fermentation under the conditions that are most relevant to continuous cultures. To this end, dynamic sensitivity analysis is performed to systematically investigate the effects of culture conditions, reaction kinetics, and enzymes on the dynamics of the ABE production pathway. The analysis provides guidance for future metabolic engineering and fermentation optimization studies. PMID:27486663

Effect of pH on ethanol-type acidogenic fermentation of fruit and vegetable waste.

PubMed

Wu, Yuanyuan; Wang, Cuiping; Zheng, Mingyue; Zuo, Jiane; Wu, Jing; Wang, Kaijun; Yang, Boqiong

2017-02-01

The aim of this study was to investigate the possibility and optimal controlling strategy for ethanol-type acidogenic fermentation of fruit and vegetable waste by mixed microbial cultures. Four continuous stirred tank reactors (CSTR) were operated at various pHs (4.0, 5.0, 5.5, and 6.0) with an organic loading rate of 13gVS/(Ld) and hydraulic retention time of 3d. Butyrate-type fermentation was observed at pH 5.0, 5.5, and 6.0. Conversely, at pH 4.0, ethanol-type fermentation was observed with a high mass concentration and proportion (of total fermentative products) of ethanol, which were 6.7g/L and 88.8%, respectively. However, the total concentration of ethanol-type fermentative products substantially decreased from days 22-25. The optimal pH of ethanol-type fermentative microorganisms was investigated by using batch experiments with pH controlled at 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, and 7.0 and results showed that the maximum ethanol concentration and relatively highest acidogenic rate were found at pH of 5.5. The pH in the long term CSTR was changed from 4.0 to 5.5 to improve ethanol-type fermentation and results showed that ethanol-type fermentation was improved temporarily, however, was followed by the reappearance of butyrate-type fermentation. In addition, ethanol-type fermentation recovered once more when pH was reverted to 4.0. Therefore, the results of this study suggest that a process of dynamic, sequenced pH control with the order pH 4.0, 5.5 and 4.0 might be a feasible controlling strategy for continuous and stable ethanol-type fermentation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Improvement on the productivity of continuous tequila fermentation by Saccharomyces cerevisiae of Agave tequilana juice with supplementation of yeast extract and aeration.

PubMed

Hernández-Cortés, Guillermo; Valle-Rodríguez, Juan Octavio; Herrera-López, Enrique J; Díaz-Montaño, Dulce María; González-García, Yolanda; Escalona-Buendía, Héctor B; Córdova, Jesús

2016-12-01

Agave (Agave tequilana Weber var. azul) fermentations are traditionally carried out employing batch systems in the process of tequila manufacturing; nevertheless, continuous cultures could be an attractive technological alternative to increase productivity and efficiency of sugar to ethanol conversion. However, agave juice (used as a culture medium) has nutritional deficiencies that limit the implementation of yeast continuous fermentations, resulting in high residual sugars and low fermentative rates. In this work, fermentations of agave juice using Saccharomyces cerevisiae were put into operation to prove the necessity of supplementing yeast extract, in order to alleviate nutritional deficiencies of agave juice. Furthermore, continuous fermentations were performed at two different aeration flow rates, and feeding sterilized and non-sterilized media. The obtained fermented musts were subsequently distilled to obtain tequila and the preference level was compared against two commercial tequilas, according to a sensorial analysis. The supplementation of agave juice with air and yeast extract augmented the fermentative capacity of S. cerevisiae S1 and the ethanol productivities, compared to those continuous fermentations non supplemented. In fact, aeration improved ethanol production from 37 to 40 g L(-1), reducing sugars consumption from 73 to 88 g L(-1) and ethanol productivity from 3.0 to 3.2 g (Lh)(-1), for non-aerated and aerated (at 0.02 vvm) cultures, respectively. Supplementation of yeast extract allowed an increase in specific growth rate and dilution rates (0.12 h(-1), compared to 0.08 h(-1) of non-supplemented cultures), ethanol production (47 g L(-1)), reducing sugars consumption (93 g L(-1)) and ethanol productivity [5.6 g (Lh)(-1)] were reached. Additionally, the effect of feeding sterilized or non-sterilized medium to the continuous cultures was compared, finding no significant differences between both types of cultures. The overall effect of adding yeast extract and air to the continuous fermentations resulted in 88 % increase in ethanol productivity. For all cultures, pH was not controlled, reaching low pH values (from 2.6 to 3). This feature suggested a reduced probability of contamination for prolonged continuous cultures and explained why no significant differences were found between continuous cultures fed with sterilized or non-sterilized media. Concentrations of volatile compounds quantified in the distillates (tequila) were in the allowed ranges established by the Mexican regulation of tequila (NOM-006-SCFI-2012, Norma Oficial Mexicana: Bebidas alcohólicas-Tequila-specificaciones, 2012). The preference level of the distillates was similar to that of two well-known commercial tequilas. The results suggested the possibility of implementing this innovative technology on an industrial scale, attaining high productivities and using non-sterilized agave juice.

Discovery and History of Amino Acid Fermentation.

PubMed

Hashimoto, Shin-Ichi

There has been a strong demand in Japan and East Asia for L-glutamic acid as a seasoning since monosodium glutamate was found to present umami taste in 1907. The discovery of glutamate fermentation by Corynebacterium glutamicum in 1956 enabled abundant and low-cost production of the amino acid, creating a large market. The discovery also prompted researchers to develop fermentative production processes for other L-amino acids, such as lysine. Currently, the amino acid fermentation industry is so huge that more than 5 million metric tons of amino acids are manufactured annually all over the world, and this number continues to grow. Research on amino acid fermentation fostered the notion and skills of metabolic engineering which has been applied for the production of other compounds from renewable resources. The discovery of glutamate fermentation has had revolutionary impacts on both the industry and science. In this chapter, the history and development of glutamate fermentation, including the very early stage of fermentation of other amino acids, are reviewed.

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

PubMed Central

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

2013-01-01

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

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

PubMed

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

2013-04-01

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

Brettanomyces yeasts--From spoilage organisms to valuable contributors to industrial fermentations.

PubMed

Steensels, Jan; Daenen, Luk; Malcorps, Philippe; Derdelinckx, Guy; Verachtert, Hubert; Verstrepen, Kevin J

2015-08-03

Ever since the introduction of controlled fermentation processes, alcoholic fermentations and Saccharomyces cerevisiae starter cultures proved to be a match made in heaven. The ability of S. cerevisiae to produce and withstand high ethanol concentrations, its pleasant flavour profile and the absence of health-threatening toxin production are only a few of the features that make it the ideal alcoholic fermentation organism. However, in certain conditions or for certain specific fermentation processes, the physiological boundaries of this species limit its applicability. Therefore, there is currently a strong interest in non-Saccharomyces (or non-conventional) yeasts with peculiar features able to replace or accompany S. cerevisiae in specific industrial fermentations. Brettanomyces (teleomorph: Dekkera), with Brettanomyces bruxellensis as the most commonly encountered representative, is such a yeast. Whilst currently mainly considered a spoilage organism responsible for off-flavour production in wine, cider or dairy products, an increasing number of authors report that in some cases, these yeasts can add beneficial (or at least interesting) aromas that increase the flavour complexity of fermented beverages, such as specialty beers. Moreover, its intriguing physiology, with its exceptional stress tolerance and peculiar carbon- and nitrogen metabolism, holds great potential for the production of bioethanol in continuous fermentors. This review summarizes the most notable metabolic features of Brettanomyces, briefly highlights recent insights in its genetic and genomic characteristics and discusses its applications in industrial fermentation processes, such as the production of beer, wine and bioethanol. Copyright © 2015. Published by Elsevier B.V.

Halophiles, coming stars for industrial biotechnology.

PubMed

Yin, Jin; Chen, Jin-Chun; Wu, Qiong; Chen, Guo-Qiang

2015-11-15

Industrial biotechnology aims to produce chemicals, materials and biofuels to ease the challenges of shortage on petroleum. However, due to the disadvantages of bioprocesses including energy consuming sterilization, high fresh water consumption, discontinuous fermentation to avoid microbial contamination, highly expensive stainless steel fermentation facilities and competing substrates for human consumption, industrial biotechnology is less competitive compared with chemical processes. Recently, halophiles have shown promises to overcome these shortcomings. Due to their unique halophilic properties, some halophiles are able to grow in high pH and high NaCl containing medium under higher temperature, allowing fermentation processes to run contamination free under unsterile conditions and continuous way. At the same time, genetic manipulation methods have been developed for halophiles. So far, halophiles have been used to produce bioplastics polyhydroxyalkanoates (PHA), ectoines, enzymes, and bio-surfactants. Increasing effects have been made to develop halophiles into a low cost platform for bioprocessing with advantages of low energy, less fresh water consumption, low fixed capital investment, and continuous production. Copyright © 2014 Elsevier Inc. All rights reserved.

CO2 fixation by anaerobic non-photosynthetic mixotrophy for improved carbon conversion.

PubMed

Jones, Shawn W; Fast, Alan G; Carlson, Ellinor D; Wiedel, Carrissa A; Au, Jennifer; Antoniewicz, Maciek R; Papoutsakis, Eleftherios T; Tracy, Bryan P

2016-09-30

Maximizing the conversion of biogenic carbon feedstocks into chemicals and fuels is essential for fermentation processes as feedstock costs and processing is commonly the greatest operating expense. Unfortunately, for most fermentations, over one-third of sugar carbon is lost to CO 2 due to the decarboxylation of pyruvate to acetyl-CoA and limitations in the reducing power of the bio-feedstock. Here we show that anaerobic, non-photosynthetic mixotrophy, defined as the concurrent utilization of organic (for example, sugars) and inorganic (for example, CO 2 ) substrates in a single organism, can overcome these constraints to increase product yields and reduce overall CO 2 emissions. As a proof-of-concept, Clostridium ljungdahlii was engineered to produce acetone and achieved a mass yield 138% of the previous theoretical maximum using a high cell density continuous fermentation process. In addition, when enough reductant (that is, H 2 ) is provided, the fermentation emits no CO 2 . Finally, we show that mixotrophy is a general trait among acetogens.

Elimination patterns of worldwide used sulfonamides and tetracyclines during anaerobic fermentation.

PubMed

Spielmeyer, Astrid; Breier, Bettina; Groißmeier, Kathrin; Hamscher, Gerd

2015-10-01

Antibiotics such as sulfonamides and tetracyclines are frequently used in veterinary medicine. Due to incomplete absorption in the animal gut and/or unmetabolized excretion, the substances can enter the environment by using manure as soil fertilizer. The anaerobic fermentation process of biogas plants is discussed as potential sink for antibiotic compounds. However, negative impacts of antibiotics on the fermentation process are suspected. The elimination of sulfadiazine, sulfamethazine, tetracycline and chlortetracycline in semi-continuous lab-scale fermenters was investigated. Both biogas production and methane yield were not negatively affected by concentrations up to 38 mg per kg for sulfonamides and 7 mg per kg for tetracyclines. All substances were partly eliminated with elimination rates between 14% and 89%. Both matrix and structure of the target molecule influenced the elimination rate. Chlortetracycline was mainly transformed into iso-chlortetracycline. In all other cases, the elimination pathways remained undiscovered; however, sorption processes seem to have a negligible impact. Copyright © 2015 Elsevier Ltd. All rights reserved.

Wine yeasts for the future.

PubMed

Fleet, Graham H

2008-11-01

International competition within the wine market, consumer demands for newer styles of wines and increasing concerns about the environmental sustainability of wine production are providing new challenges for innovation in wine fermentation. Within the total production chain, the alcoholic fermentation of grape juice by yeasts is a key process where winemakers can creatively engineer wine character and value through better yeast management and, thereby, strategically tailor wines to a changing market. This review considers the importance of yeast ecology and yeast metabolic reactions in determining wine quality, and then discusses new directions for exploiting yeasts in wine fermentation. It covers criteria for selecting and developing new commercial strains, the possibilities of using yeasts other than those in the genus of Saccharomyces, the prospects for mixed culture fermentations and explores the possibilities for high cell density, continuous fermentations.

Development of a high temperature microbial fermentation process for butanol

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

Jeor, Jeffery D. St.; Reed, David W.; Daubaras, Dayna L.

2015-08-01

Transforming renewable biomass into cost-competitive high-performance biofuels and bioproducts is key to the U.S. future energy and chemical needs. Butanol production by microbial fermentation for chemical conversion to polyolefins, elastomers, drop-in jet or diesel fuel, and other chemicals is a promising solution. A high temperature fermentation process could decrease energy costs, capital cost, give higher butanol production, and allow for continuous fermentation. In this paper, we describe our approach to genetically transform Geobacillus caldoxylosiliticus, using a pUCG18 plasmid, for potential insertion of a butanol production pathway. Transformation methods tested were electroporation of electrocompetent cells, ternary conjugation with E. coli donormore » and helper strains, and protoplast fusion. These methods have not been successful using the current plasmid. Growth controls show cells survive the various methods tested, suggesting the possibility of transformation inhibition from a DNA restriction modification system in G. caldoxylosiliticus, as reported in the literature.« less

Advanced bioreactors for enhanced production of chemicals

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

Davison, B.H.; Scott, C.D.

1993-06-01

A variety of advanced bioreactors are being developed to improve production of fuels, solvents, organic acids and other fermentation products. One key approach is immobilization of the biocatalyst leading to increased rates and yields. In addition, there are processes for simultaneous fermentation and separation to further increase production by the removal of an inhibitory product. For example, ethanol productivity in immobilized-cell fluidized-bed bioreactors (FBRs) can increase more than tenfold with 99% conversion and near stoichiometric yields. Two modified FBR configurations offer further improvements by removing the inhibitory product directly from the continuous fermentation. One involves the addition and removal ofmore » solid adsorbent particles to the FBR. This process was demonstrated with the production of lactic acid by immobilized Lactobacillus. The second uses an immiscible organic extractant in the FBR. This increased total butanol yields in the anaerobic acetone-butanol fermentation by Clostridium acetobutylicum.« less

Real-time understanding of lignocellulosic bioethanol fermentation by Raman spectroscopy

PubMed Central

2013-01-01

Background A substantial barrier to commercialization of lignocellulosic ethanol production is a lack of process specific sensors and associated control strategies that are essential for economic viability. Current sensors and analytical techniques require lengthy offline analysis or are easily fouled in situ. Raman spectroscopy has the potential to continuously monitor fermentation reactants and products, maximizing efficiency and allowing for improved process control. Results In this paper we show that glucose and ethanol in a lignocellulosic fermentation can be accurately monitored by a 785 nm Raman spectroscopy instrument and novel immersion probe, even in the presence of an elevated background thought to be caused by lignin-derived compounds. Chemometric techniques were used to reduce the background before generating calibration models for glucose and ethanol concentration. The models show very good correlation between the real-time Raman spectra and the offline HPLC validation. Conclusions Our results show that the changing ethanol and glucose concentrations during lignocellulosic fermentation processes can be monitored in real-time, allowing for optimization and control of large scale bioconversion processes. PMID:23425590

Preliminary study of acrylamide monomer decomposition during methane fermentation of dairy waste sludge.

PubMed

Mroczek, Ewelina; Konieczny, Piotr; Lewicki, Andrzej; Waśkiewicz, Agnieszka; Dach, Jacek

2016-07-01

Polyacrylamide (PAM) used in sludge dewatering exists widely in high-solid anaerobic digestion. Acrylamide is registered in the list of chemicals demonstrating toxic, carcinogenic and mutagenic properties. Therefore, it is reasonable to ask about the mobility of such residual substances in the environment. The study was carried out to assess the impact of the mesophilic (39±1°C) and thermophilic (54±1°C) fermentation process on the level of acrylamide monomer (AMD) content in the dairy sludge. The material was analysed using high-performance liquid chromatography (HPLC) for quantification of AMD. The results indicate that the process of methane fermentation continues regardless of the temperature effects on the degradation of AMD in dairy sludge. The degree of reduction of acrylamide monomer for thermophilic fermentation is 100%, while for mesophilic fermentation it is 91%. In practice, this means that biogas technology eliminates the risk of AMD migration to plant tissue. Moreover, it should be stressed that 90% of cumulative biogas and methane production was reached one week earlier under thermophilic conditions - the dynamics of the methanisation process were over 20% faster. Copyright © 2016. Published by Elsevier B.V.

The production of chemicals from food processing wastes using a novel fermenter separator. Annual progress report, January 1993--March 1994

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

Dale, M.C.; Venkatesh, K.V.; Choi, H.

The basic objective of this project is to convert waste streams from the food processing industry to usable fuels and chemicals using novel bioreactors. These bioreactors should allow economical utilization of waste (whey, waste sugars, waste starch, bottling wastes, candy wastes, molasses, and cellulosic wastes) by the production of ethanol, acetone/butanol, organic acids (acetic, lactic, and gluconic), yeast diacetyl flavor, and antifungal compounds. Continuous processes incorporating various processing improvements such as simultaneous product separation and immobilized cells are being developed to allow commercial scale utilization of waste stream. The production of ethanol by a continuous reactor-separator is the process closestmore » to commercialization with a 7,500 liter pilot plant presently sited at an Iowa site to convert whey lactose to ethanol. Accomplishments during 1993 include installation and start-up of a 7,500 liter ICRS for ethanol production at an industry site in Iowa; Donation and installation of a 200 liter yeast pilot Plant to the project from Kenyon Enterprises; Modeling and testing of a low energy system for recovery of ethanol from vapor is using a solvent absorption/extractive distillation system; Simultaneous saccharification/fermentation of raw corn grits and starch in a stirred reactor/separator; Testing of the ability of `koji` process to ferment raw corn grits in a `no-cook` process.« less

Synergistic dark and photo-fermentation continuous system for hydrogen production from molasses by Clostridium acetobutylicum ATCC 824 and Rhodobacter capsulatus DSM 1710.

PubMed

Morsy, Fatthy Mohamed

2017-04-01

This study investigated synergistic dark and photo-fermentation using continuous fermentation system (CFS). The system relies on connecting several fermenters from bottom of one to top culture level of the next in a manner that allows for delaying movement of the substrate and thus for its full consumption. While H 2 was collected, CFS allowed for moving liquid byproducts toward the outlet and hence continuous productivity. CFS could be efficiently used for: (1) Continuous dark and photo-fermentation H 2 production by Clostridium acetobutylicum and Rhodobacter capsulatus producing 5.65moleH 2 mole -1 hexose; (2) Continuous dark-fermentation synergistic H 2 , acetone, butanol and ethanol (ABE) production by C. acetobutylicum which produced per mole hexose, 2.43mol H 2 along with 73.08g ABE (3) Continuous H 2 and methane production by C. acetobutylicum and bacterial sludge producing, per mole hexose, 1.64mol pure H 2 and 2.56mol CH 4 mixed with 0.37mol H 2 ·The hydraulic retention time (HRT) for whole system was short where organic acids produced in dark-fermentation in first fermenter were synergistically utilized for H 2 production by R. capsulatus in subsequent fermenters. CFS is suitable for fast-digestible sugars but not lignocelluloses or other hard-digestible organics, requiring prolonged HRT, unless such polymeric organics were hydrolyzed prior to fermentation. Copyright © 2017 Elsevier B.V. All rights reserved.

A novel membrane-integrated fermentation reactor system: application to pyruvic acid production in continuous culture by Torulopsis glabrata.

PubMed

Sawai, Hideki; Mimitsuka, Takashi; Minegishi, Shin-Ichi; Henmi, Masahiro; Yamada, Katsushige; Shimizu, Sakayu; Yonehara, Tetsu

2011-08-01

This paper describes the performance of a novel bio-reactor system, the membrane-integrated fermentation reactor (MFR), for efficient continuous fermentation. The MFR, equipped with an autoclavable polyvinylidene difluoride membrane, has normally been used for biological wastewater treatment. The productivity of the MFR system, applied to the continuous production of pyruvic acid by the yeast Torulopsis glabrata, was remarkably high. The volumetric productivity of pyruvic acid increased up to 4.2 g/l/h, about four times higher than that of batch fermentation. Moreover, the membrane was able to filter fermentation broth for more than 300 h without fouling even though the cell density of the fermentation broth reached 600 as OD(660). Transmembrane pressure, used as an indicator of membrane fouling, remained below 5 kPa throughout the continuous fermentation. These results clearly indicate that the MFR system is a simple and highly efficient system that is applicable to the fermentative production of a range of biochemicals.

Continuous cultivation approach for fermentative succinic acid production from crude glycerol by Basfia succiniciproducens DD1.

PubMed

Scholten, Edzard; Renz, Torsten; Thomas, Jochen

2009-12-01

A continuous cultivation process for the fermentative production of succinic acid from glycerol with the recently isolated bacterium Basfia succiniciproducens DD1 was developed. Crude glycerol (5.1 g l(-1)) was used as C-source and NH(4)OH as N-source and pH-control agent. The problem of wall growth was solved by transfers of the cultivation broth into an empty identical fermentor. The resulting continuous cultivation process was maintained for more than 80 days. Glycerol-limited steady states were established for dilution rates between 0.004 and 0.018 h(-1). Higher dilution rates resulted in glycerol accumulation. Succinic acid concentrations, productivities, yields and specific productivities increased with increasing dilution rates: at 0.018 h(-1) the highest values were 5.21 g l(-1), 0.094 g l(-1) h(-1), 1.02 g g(-1) and 0.375 g g(-1) h(-1), respectively.

Evaluation of pretreatment methods on mixed inoculum for both batch and continuous thermophilic biohydrogen production from cassava stillage.

PubMed

Luo, Gang; Xie, Li; Zou, Zhonghai; Wang, Wen; Zhou, Qi

2010-02-01

Anaerobic sludges, pretreated by chloroform, base, acid, heat and loading-shock, as well as untreated sludge were evaluated for their thermophilic fermentative hydrogen-producing characters from cassava stillage in both batch and continuous experiments. Results showed that the highest hydrogen production was obtained by untreated sludge and there were significant differences (p<0.05) in hydrogen yields (varied from 32.9 to 65.3mlH(2)/gVS) among the tested pretreatment methods in batch experiments. However, the differences in hydrogen yields disappeared in continuous experiments, which indicated the pretreatment methods had only short-term effects on the hydrogen production. Further study showed that alkalinity was a crucial parameter influencing the fermentation process. When the influent was adjusted to pH 6 by NaHCO(3) instead of NaOH, the hydrogen yield increased from about 40 to 52mlH(2)/gVS in all the experiments. Therefore, pretreatment of anaerobic sludge is unnecessary for practical thermophilic fermentative hydrogen production from cassava stillage.

Filamentous fungal diversity and community structure associated with the solid state fermentation of Chinese Maotai-flavor liquor.

PubMed

Chen, Bi; Wu, Qun; Xu, Yan

2014-06-02

Maotai-flavor liquor is produced by simultaneous saccharification and fermentation (SSF) process under solid state conditions, including Daqu (starter) making, stacking fermentation and alcohol fermentation stages. Filamentous fungi produce many enzymes to degrade the starch material into fermentable sugar during liquor fermentation. This study investigated the filamentous fungal community associated with liquor making process. Eight and seven different fungal species were identified by using culture-dependent and -independent method (PCR-denaturing gradient gel electrophoresis, DGGE) analyses, respectively. The traditional enumeration method showed that Daqu provided 7 fungal species for stacking fermentation. The total population of filamentous fungi increased from 3.4 × 10(3)cfu/g to 1.28 × 10(4)cfu/g in the first 3 days of stacking fermentation, and then decreased till the end. In alcohol fermentation in pits, the population continuously decreased and few fungal species survived (lower than 1 × 10(3)cfu/g) after 10 days. Therefore, stacking fermentation is an essential stage for the growth of filamentous fungi. Paecilomyces variotii, Aspergillus oryzae and Aspergillus terreus were detected by both methods, and P. variotii and A. oryzae were the predominant species. Meanwhile, P. variotii possessed the highest glucoamylase (3252 ± 526 U/g) and A. oryzae exhibited the highest α-amylase (1491 ± 324 U/g) activity among the cultivable fungal species. Furthermore, the variation of starch and reducing sugar content was consistent with the growth of P. variotii and A. oryzae in Zaopei (fermented grains) during stacking fermentation, which implied that the two filamentous fungi played an important role in producing amylase for hydrolyzing the starch. Copyright © 2014 Elsevier B.V. All rights reserved.

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

PubMed

Papagianni, Maria

2007-01-01

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

Metabolic and transcriptomic response of the wine yeast Saccharomyces cerevisiae strain EC1118 after an oxygen impulse under carbon-sufficient, nitrogen-limited fermentative conditions.

PubMed

Orellana, Marcelo; Aceituno, Felipe F; Slater, Alex W; Almonacid, Leonardo I; Melo, Francisco; Agosin, Eduardo

2014-05-01

During alcoholic fermentation, Saccharomyces cerevisiae is exposed to continuously changing environmental conditions, such as decreasing sugar and increasing ethanol concentrations. Oxygen, a critical nutrient to avoid stuck and sluggish fermentations, is only discretely available throughout the process after pump-over operation. In this work, we studied the physiological response of the wine yeast S. cerevisiae strain EC1118 to a sudden increase in dissolved oxygen, simulating pump-over operation. With this aim, an impulse of dissolved oxygen was added to carbon-sufficient, nitrogen-limited anaerobic continuous cultures. Results showed that genes related to mitochondrial respiration, ergosterol biosynthesis, and oxidative stress, among other metabolic pathways, were induced after the oxygen impulse. On the other hand, mannoprotein coding genes were repressed. The changes in the expression of these genes are coordinated responses that share common elements at the level of transcriptional regulation. Beneficial and detrimental effects of these physiological processes on wine quality highlight the dual role of oxygen in 'making or breaking wines'. These findings will facilitate the development of oxygen addition strategies to optimize yeast performance in industrial fermentations. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Syngas fermentation in a 100-L pilot scale fermentor: design and process considerations.

PubMed

Kundiyana, Dimple K; Huhnke, Raymond L; Wilkins, Mark R

2010-05-01

Fermentation of syngas offers several advantages compared to chemical catalysts such as higher specificity of biocatalysts, lower energy costs, and higher carbon efficiency. Scale-up of syngas fermentation from a bench scale to a pilot scale fermentor is a critical step leading to commercialization. The primary objective of this research was to install and commission a pilot scale fermentor, and subsequently scale-up the Clostridium strain P11 fermentation from a 7.5-L fermentor to a pilot scale 100-L fermentor. Initial preparation and fermentations were conducted in strictly anaerobic conditions. The fermentation system was maintained in a batch mode with continuous syngas supply. The effect of anaerobic fermentation in a pilot scale fermentor was evaluated. In addition, the impact of improving the syngas mass transfer coefficient on the utilization and product formation was studied. Results indicate a six fold improvement in ethanol concentration compared to serum bottle fermentation, and formation of other compounds such as isopropyl alcohol, acetic acid and butanol, which are of commercial importance. (c) 2009 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Immobilization of Microbial Cells for Alcoholic and Malolactic Fermentation of Wine and Cider

NASA Astrophysics Data System (ADS)

Kourkoutas, Yiannis; Manojlović, Verica; Nedović, Viktor A.

Wine- or cider-making is highly associated with biotechnology owing to the traditional nature of must fermentation.. Nowadays, there have been considerable developments in wine- or cider-making techniques affecting all phases of wine or cider production, but more importantly, the fermentation process. It is well-known that the transformation of grape must by microbial activity results in the production of wine, and the fermentation of apples (or sometimes pears) in the production of cider. In this process, a variety of compounds affecting the organoleptic profile of wine or cider are synthesized. It is also common sense that in wine- or cider-making, the main objective is to achieve an adequate quality of the product. The technological progress and the improved quality of the wines or ciders have been associated with the control of technical parameters. Herein, cell immobilization offers numerous advantages, such as enhanced fermentation productivity, ability for cell recycling, application of continuous configurations, enhanced cell stability and viability, and improvement of quality (Margaritis and Merchant 1984; Stewart and Russel 1986; Kourkoutas et al. 2004a).

Analysis of trickle-bed reactor for ethanol production from syngas using Clostridium ragsdalei

NASA Astrophysics Data System (ADS)

Devarapalli, Mamatha

The conversion of syngas components (CO, CO2 and H2) to liquid fuels such as ethanol involves complex biochemical reactions catalyzed by a group of acetogens such as Clostridium ljungdahlii, Clostridium carboxidivorans and Clostridium ragsdalei. The low ethanol productivity in this process is associated with the low solubility of gaseous substrates CO and H2 in the fermentation medium. In the present study, a 1-L trickle-bed reactor (TBR) was analyzed to understand its capabilities to improve the mass transfer of syngas in fermentation medium. Further, semi-continuous and continuous syngas fermentations were performed using C. ragsdalei to evaluate the ability of the TBR for ethanol production. In the mass transfer studies, using 6-mm glass beads, it was found that the overall mass transfer coefficient (kLa/V L) increased with the increase in gas flow rate from 5.5 to 130.5 sccm. Further, an increase in the liquid flow rate in the TBR decreased the kLa/VL due to the increase in liquid hold up volume (VL) in the packing. The highest kLa/VL values of 421 h-1 and 178 h-1 were achieved at a gas flow rate of 130.5 sccm for 6-mm and 3-mm glass beads, respectively. Semi-continuous fermentations were performed with repetitive medium replacement in counter-current and co-current modes. In semi-continuous fermentations with syngas consisting of 38% CO, 5% N2, 28.5% CO2 and 28.5% H2 (by volume), the increase in H2 conversion (from 18 to 55%) and uptake (from 0.7 to 2.2 mmol/h) were observed. This increase was attributed to more cell attachment in the packing that reduced CO inhibition to hydrogenase along the column length and increased the H2 uptake. The maximum ethanol produced during counter-current and co-current modes were 3.0 g/L and 5.7 g/L, respectively. In continuous syngas fermentation, the TBR was operated at dilution rates between 0.006 h-1and 0.012 h -1 and gas flow rates between 1.5 sccm and 18.9 sccm. The highest ethanol concentration of 13 g/L was achieved at dilution and gas flow rates of 0.012 h-1 and 18.9 sccm, respectively. The molar ratio of ethanol to acetic acid of 4:1 was obtained during continuous fermentation which was 7.7 times higher than in semi-continuous fermentations. The improvement of the reactor performance in continuous mode gives scope to explore the TBR as a potential bioreactor design for large scale biofuels production.

Biotechnological production of gluconic acid: future implications.

PubMed

Singh, Om V; Kumar, Raj

2007-06-01

Gluconic acid (GA) is a multifunctional carbonic acid regarded as a bulk chemical in the food, feed, beverage, textile, pharmaceutical, and construction industries. The favored production process is submerged fermentation by Aspergillus niger utilizing glucose as a major carbohydrate source, which accompanied product yield of 98%. However, use of GA and its derivatives is currently restricted because of high prices: about US$ 1.20-8.50/kg. Advancements in biotechnology such as screening of microorganisms, immobilization techniques, and modifications in fermentation process for continuous fermentation, including genetic engineering programmes, could lead to cost-effective production of GA. Among alternative carbohydrate sources, sugarcane molasses, grape must show highest GA yield of 95.8%, and banana must may assist reducing the overall cost of GA production. These methodologies would open new markets and increase applications of GA.

Fermentative hydrogen production from soybean protein processing wastewater in an anaerobic baffled reactor (ABR) using anaerobic mixed consortia.

PubMed

Zhu, Ge-fu; Li, Jian-zheng; Liu, Chao-xiang

2012-09-01

Fermentative H(2) production from soybean protein processing wastewater (SPPW) was investigated in a four-compartment anaerobic baffled reactor (ABR) using anaerobic mixed cultures under continuous flow condition in the present study. After being inoculated with aerobic activated sludge and operated at the inoculants of 5.98 gVSS L(-1), COD of 5000 mg L(-1), HRT of 16 h and temperature of (35 ± 1) °C for 22 days, the ABR achieved stable ethanol-type fermentation. The specific hydrogen production rate of anaerobic activated sludge was 165 LH(2)kg MLVSS(-1) day(-1), the substrate conversion rate was 600.83 LH(2)kg COD(-1)and the COD removal efficiency was 44.73% at the stable operation status. The ABR system exhibited a better stability and higher hydrogen yields than continuous stirring tank reactor under the same operational condition. The experimental data documented the feasibility of substrate degradation along with molecular H(2) generation utilizing SPPW as primary carbon source in the ABR system.

Lignocellulose fermentation and residual solids characterization for senescent switchgrass fermentation by Clostridium thermocellum in the presence and absence of continuous in situ ball-milling

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

Balch, Michael L.; Holwerda, Evert K.; Davis, Mark F.

Milling during lignocellulosic fermentation, henceforth referred to as cotreatment, is investigated as an alternative to thermochemical pretreatment as a means of enhancing biological solubilization of lignocellulose. We investigate the impact of milling on soluble substrate fermentation by Clostridium thermocellum with comparison to yeast, document solubilization for fermentation of senescent switchgrass with and without ball milling, and characterize residual solids. Soluble substrate fermentation by C. thermocellum proceeded readily in the presence of continuous ball milling but was completely arrested for yeast. Total fractional carbohydrate solubilization achieved after fermentation of senescent switchgrass by C. thermocellum for 5 days was 0.45 without cotreatmentmore » or pretreatment, 0.81 with hydrothermal pretreatment (200 degrees C, 15 minutes, severity 4.2), and 0.88 with cotreatment. Acetate and ethanol were the main fermentation products, and were produced at similar ratios with and without cotreatment. Analysis of solid residues was undertaken using molecular beam mass spectrometry (PyMBMS) and solid-state nuclear magnetic resonance spectroscopy (NMR) in order to provide insight into changes in plant cell walls during processing via various modes. The structure of lignin present in residual solids remaining after fermentation with cotreatment appeared to change little, with substantially greater changes observed for hydrothermal pretreatment - particularly with respect to formation of C-C bonds. The observation of high solubilization with little apparent modification of the residue is consistent with cotreatment enhancing solubilization primarily by increasing the access of saccharolytic enzymes to the feedstock, and C. thermocellum being able to attack all the major linkages in cellulosic biomass provided that these linkages are accessible.« less

40 CFR Table 4 to Subpart Cccc of... - Continuous Compliance With Emission Limitations

Code of Federal Regulations, 2013 CFR

2013-07-01

... Yeast Pt. 63, Subpart CCCC, Table 4 Table 4 to Subpart CCCC of Part 63—Continuous Compliance With... fermenter producing yeast in a fermentation stage (last (Trade), second-to-last (First Generation), or third... the applicable maximum concentration. 2. Each fed-batch fermenter producing yeast in a fermentation...

40 CFR Table 4 to Subpart Cccc of... - Continuous Compliance With Emission Limitations

Code of Federal Regulations, 2014 CFR

2014-07-01

... Yeast Pt. 63, Subpart CCCC, Table 4 Table 4 to Subpart CCCC of Part 63—Continuous Compliance With... fermenter producing yeast in a fermentation stage (last (Trade), second-to-last (First Generation), or third... the applicable maximum concentration. 2. Each fed-batch fermenter producing yeast in a fermentation...

40 CFR Table 4 to Subpart Cccc of... - Continuous Compliance With Emission Limitations

Code of Federal Regulations, 2012 CFR

2012-07-01

... Yeast Pt. 63, Subpart CCCC, Table 4 Table 4 to Subpart CCCC of Part 63—Continuous Compliance With... fermenter producing yeast in a fermentation stage (last (Trade), second-to-last (First Generation), or third... the applicable maximum concentration. 2. Each fed-batch fermenter producing yeast in a fermentation...

BER-Myriant Succinic Acid Biorefinery

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

Shmorhun, Mark

Myriant Corporation (Myriant) has successfully produced the bioproduct succinic acid by the fermentation of glucose at a commercial scale operation in Lake Providence, Louisiana. The MySAB facility (Myriant Succinic Acid Biorefinery) came on stream in May 2013 and has been producing product since then. The MySAB facility is a demonstration-scale plant, capable of utilizing sorghum grits and commercially available dextrose, to ferment glucose into succinic acid. A downstream processing train has demonstrated the ability to produce an industrial, a standard and a polymer grade product. It consists of cell separation, membrane filtration, continuous chromatography, polishing to remove ionic and colormore » bodies impurities, and final evaporation and crystallization. A by-product of the process is ammonium sulfate which is sold as a liquid fertilizer product. Since 2007 when development work began in the Woburn, Massachusetts R&D laboratories, the succinic acid bio-process has evolved through: Process development (microbiology, fermentation, and downstream) – R&D development laboratories; Piloting efforts at Fermic S.A. de C.V., Mexico City, Mexico – upstream and downstream processes; Design, construction, commissioning, and commercial production operations at the MySAB facility Additionally, Myriant became a wholly-owned subsidiary of the PTT Global Chemical Plc., Thailand, in late 2015, their investment into and support of Myriant goes back to 2011. The support of PTT Global Chemical Plc. helped to improve the upstream and downstream processes, and produce significant metric ton quantities of high quality bio-based succinic acid. The product has gone into a number of commercial markets worldwide for customer applications, development and production. The experience base gained via operations at the MySAB facility since May 2013, along with continued R&D development efforts involving Microbiology, Fermentation, and Downstream processes, at both the Woburn, Massachusetts and PTT Global Chemical Plc. Thailand laboratories, positions the company well for future production at the plant and commercialization of new bio-based products. This will be especially important and valuable as the green chemistry business climate continues to take root and flourish.« less

Characterization of bacterial consortium and its application in an ectopic fermentation system.

PubMed

Guo, Hui; Geng, Bing; Liu, Xue; Ye, Jing; Zhao, Yongkun; Zhu, Changxiong; Yuan, Hongli

2013-07-01

This study aimed to develop an ectopic fermentation system (EFS) to reduce the pollution of cow wastewater and to provide a basis for the production of biofertilizer with fermentation residues. Six thermophilic strains, three of which have efficient cellulose-degrading abilities and the other have good ammonia-N utilizing abilities, were chosen as the microbial inocula. The results showed that EFS inoculated with microbial consortium brought higher temperature and more wastewater was needed to ensure continuous fermentation. The pH values decreased in the early stage of fermentation, and then increased during the process. It caused increases in total Kjeldahl nitrogen, total phosphorous, and total potassium content. Decreases in organic matter content and C/N ratio were also observed. The high level of nutrients indicated the suitability of the paddings after fermentation for agronomic uses. It firstly attempted to combine cow wastewater treatment and bio-organic fertilizer production by EFS with mixed microbial culture. Copyright © 2013 Elsevier Ltd. All rights reserved.

Fermentation performance optimization in an ectopic fermentation system.

PubMed

Yang, Xiaotong; Geng, Bing; Zhu, Changxiong; Li, Hongna; He, Buwei; Guo, Hui

2018-07-01

Ectopic fermentation systems (EFSs) were developed for wastewater treatment. Previous studies have investigated the ability of thermophilic bacteria to improve fermentation performance in EFS. Continuing this research, we evaluated EFS performance using principle component analysis and investigated the addition of different proportions of cow dung. Viable bacteria communities were clustered and identified using BOX-AIR-based repetitive extragenic palindromic-PCR and 16S rDNA analysis. The results revealed optimal conditions for the padding were maize straw inoculated with thermophilic bacteria. Adding 20% cow dung yielded the best pH values (6.94-8.56), higher temperatures, increased wastewater absorption, improved litter quality, and greater microbial quantities. The viable bacteria groups were enriched by the addition of thermophilic consortium, and exogenous strains G21, G14, G4-1, and CR-15 were detected in fermentation process. The proportion of Bacillus species in treatment groups reached 70.37% after fermentation, demonstrating that thermophilic bacteria, especially Bacillus, have an important role in EFS, supporting previous predictions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biotechnological production of enantiomerically pure d-lactic acid.

PubMed

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

2016-11-01

The fermentation process of l-lactic acid is well known. Little importance was attached to d-lactic acid, but in the past 10 years, d-lactic acid gained significantly in importance. d-Lactic acid is an interesting precursor for manufacturing heat-resistant polylactic acid (PLA) bioplastics which can be widely used, for example as packaging material, coatings, for textiles or in the automotive industry.This review provides a comprehensive overview of the most recent developments, including a spectrum of studied microorganisms and their capabilities for the production of d-lactic acid. Additionally, the technological achievements in biotechnological d-lactic acid production including fermentation techniques like fed batch, simultaneous saccharification, and fermentation and continuous techniques are presented. Attention is also turned to suitable alternative substrates and their applicability in fermentation processes. Furthermore, advantages and disadvantages of product recovery and purification are discussed. Economic aspects of PLA are pointed out, and the present industrial producers of lactic acid are briefly introduced.

Continuous Ethanol Fermentation of Pretreated Lignocellulosic Biomasses, Waste Biomasses, Molasses and Syrup Using the Anaerobic, Thermophilic Bacterium Thermoanaerobacter italicus Pentocrobe 411

PubMed Central

Andersen, Rasmus Lund; Jensen, Karen Møller; Mikkelsen, Marie Just

2015-01-01

Lignocellosic ethanol production is now at a stage where commercial or semi-commercial plants are coming online and, provided cost effective production can be achieved, lignocellulosic ethanol will become an important part of the world bio economy. However, challenges are still to be overcome throughout the process and particularly for the fermentation of the complex sugar mixtures resulting from the hydrolysis of hemicellulose. Here we describe the continuous fermentation of glucose, xylose and arabinose from non-detoxified pretreated wheat straw, birch, corn cob, sugar cane bagasse, cardboard, mixed bio waste, oil palm empty fruit bunch and frond, sugar cane syrup and sugar cane molasses using the anaerobic, thermophilic bacterium Thermoanaerobacter Pentocrobe 411. All fermentations resulted in close to maximum theoretical ethanol yields of 0.47–0.49 g/g (based on glucose, xylose, and arabinose), volumetric ethanol productivities of 1.2–2.7 g/L/h and a total sugar conversion of 90–99% including glucose, xylose and arabinose. The results solidify the potential of Thermoanaerobacter strains as candidates for lignocellulose bioconversion. PMID:26295944

Sugar and ethanol production from woody biomass via supercritical water hydrolysis in a continuous pilot-scale system using acid catalyst.

PubMed

Jeong, Hanseob; Park, Yong-Cheol; Seong, Yeong-Je; Lee, Soo Min

2017-12-01

The aim of this study were to efficiently produce fermentable sugars by continuous type supercritical water hydrolysis (SCWH) of Quercus mongolica at the pilot scale with varying acid catalyst loading and to use the obtained sugars for ethanol production. The SCWH of biomass was achieved in under one second (380°C, 230bar) using 0.01-0.1% H 2 SO 4 . With 0.05% H 2 SO 4 , 49.8% of sugars, including glucose (16.5% based on biomass) and xylose monomers (10.8%), were liberated from biomass. The hydrolysates were fermented with S. cerevisiae DXSP and D452-2 to estimate ethanol production. To prepare the fermentation medium, the hydrolysates were detoxified using activated charcoal and then concentrated. The ethanol yield of fermentation with S. cerevisiae DXSP was 14.1% (based on biomass). The proposed system has potential for improvement in yield through process optimization. After further development, it is expected to be a competitive alternative to traditional systems for ethanol production from woody biomass. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simultaneous Alcoholic and Malolactic Fermentations by Saccharomyces cerevisiae and Oenococcus oeni Cells Co-immobilized in Alginate Beads

PubMed Central

Bleve, Gianluca; Tufariello, Maria; Vetrano, Cosimo; Mita, Giovanni; Grieco, Francesco

2016-01-01

Malolactic fermentation (MLF) usually takes place after the end of alcoholic fermentation (AF). However, the inoculation of lactic acid bacteria together with yeast starter cultures is a promising system to enhance the quality and safety of wine. In recent years, the use of immobilized cell systems has been investigated, with interesting results, for the production of different fermented foods and beverages. In this study we have carried out the simultaneous immobilization of Saccharomyces cerevisiae and Oenococcus oeni in alginate beads and used them in microvinifications tests to produce Negroamaro wine. The process was monitored by chemical and sensorial analyses and dominance of starters and cell leaking from beads were also checked. Co-immobilization of S. cerevisiae and O. oeni allowed to perform an efficient fermentation process, producing low volatile acidity levels and ethanol and glycerol concentrations comparable with those obtained by cell sequential inoculum and co-inoculum of yeast and bacteria cells in free form. More importantly, co-immobilization strategy produced a significant decrease of the time requested to complete AF and MLF. The immobilized cells could be efficiently reused for the wine fermentation at least three times without any apparent loss of cell metabolic activities. This integrated biocatalytic system is able to perform simultaneously AF and MLF, producing wines similar in organoleptic traits in comparison with wines fermented following traditional sequential AF and MLF with free cell starters. The immobilized-cell system, that we here describe for the first time in our knowledge, offers many advantages over conventional free cell fermentations, including: (i) elimination of non-productive cell growth phases; (ii) feasibility of continuous processing; (iii) re-use of the biocatalyst. PMID:27379072

Analysis of microbiota involved in the aged natural fermentation of indigo.

PubMed

Okamoto, Takahiro; Aino, Kenichi; Narihiro, Takashi; Matsuyama, Hidetoshi; Yumoto, Isao

2017-04-01

Although the indigo reduction process is performed via natural fermentation and maintained under open-air condition, the indigo-reducing reactions continue for 6 months (on average) or longer. Identifying the mechanism underlying the maintenance of this process could lead to the development of a novel, long-lasting, unsterilized bioprocesses. To determine the mechanisms underlying the maintenance of the indigo fermentation system microbiota for more than 6 months in a reduced state in an anaerobic alkaline environment, we examined changes in the microbiota in one early-phase batch and two aged batches of indigo fermentation fluid. The microbiota in the aged fermentation fluid consisted mainly of the genera Alkalibacterium, Amphibacillus, Anaerobacillus and Polygonibacillus and the family Proteinivoraceae. The genera Alkalibacterium, Amphibacillus and Polygonibacillus are known to include indigo-reducing bacteria. Although the transition speed was slower in the aged fermentation fluid than in the early-stage fluid, the microbiota in the aged fermentation fluid maintained for more than 6 months was drastically changed within a period of 3 months. The results of this study indicate that the bacterial consortia consisted of various indigo-reducing species that replace the previous group of indigo-reducing bacteria. The notable transitional changes may be concomitant with changes in the environmental conditions, such as the nutritional conditions, observed over 3 months. This flexibility may lead to important changes in the microbiota that allow for the maintenance of a fermentation-reducing state over a long period.

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

PubMed

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

2015-01-01

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

[Continuous ethanol fermentation coupled with recycling of yeast flocs].

PubMed

Wang, Bo; Ge, Xu-Meng; Li, Ning; Bai, Feng-Wu

2006-09-01

A continuous ethanol fermentation system composed of three-stage tanks in series coupled with two sedimentation tanks was established. A self-flocculating yeast strain developed by protoplast fusion from Saccharomyces cerevisiae and Schizosaccharomyces pombe was applied. Two-stage enzymatic hydrolysate of corn powder containing 220g/L of reducing sugar, supplemented with 1.5g/L (NH4)2HPO4 and 2.5g/L KH2PO4, was used as the ethanol fermentation substrate and fed into the first fermentor at the dilution rate of 0.057h(-1). The yeast flocs separated by sedimentation were recycled into the first fermentor as two different models: activation-recycle and direct recycle. The quasi-steady states were obtained for both operation models after the fermentation systems experienced short periods of transitions. Activation process helped enhance the performance of ethanol fermentation at the high dilution rates. The broth containing more than 101g/L ethanol, 3.2g/L residual reducing sugar and 7.7g/L residual total sugar was produced. The ethanol productivity was calculated to be 5.77g/(L x h), which increased by more than 70% compared with that achieved in the same tank in series system without recycling of yeast cells.

Microbiological and biochemical survey on the transition of fermentative processes in Fukuyama pot vinegar brewing.

PubMed

Okazaki, Sachiko; Furukawa, Soichi; Ogihara, Hirokazu; Kawarai, Taketo; Kitada, Chika; Komenou, Akiko; Yamasaki, Makari

2010-06-01

Traditional brewing of Fukuyama pot vinegar is a process that has been continued in Fukuyama, Kagoshima, Japan, for almost 200 years. The entire process proceeds from raw materials, including steamed rice, rice koji (steamed rice grown with a fungus, Aspergillus oryzae) and water, to produce vinegar in roughly capped large pots laid in the open air. No special fermentative manipulation is required, except for scattering dried rice koji (called furi-koji) on the surface of the mash to form a cap-like mat on the surface at the start of brewing. As the biochemical mechanism of the natural transition of the fermentative processes during brewing has not been fully explained, we conducted a microbiological and biochemical study on the transition. First, a distinct biochemical change was observed in the brewing of spring preparation; that is, a sharp decline in pH from 6.5 to 3.5 within the first 5 days of brewing was observed due to lactic acid fermentation. Alcoholic fermentation also proceeded with a sharp increase to 4.5% ethanol within the first 5 days under the acidic conditions, suggesting that saccharification and both fermentations proceed in parallel. Acidic conditions and ethanol accumulation restricted the growth of most microorganisms in the mash, and in turn provided a favorable growth condition for acetic acid bacteria which are acid resistant and "ethanol-philic." Acetic acid was detected from day 16 and gradually increased in concentration, reaching a maximum of 7% at day 70 that was maintained thereafter. Empirically furi-koji naturally sinks into the mash after around day 40 by an unknown mechanism, allowing acetic acid bacteria to easily form pellicles on the mash surface and promoting efficient acetic acid fermentation. Dominant microbial species involved in the three fermentations were identified by denaturing gradient gel electrophoresis analysis using PCR-amplified defined-regions of small rDNA from microorganisms in the brewing mash or colony direct PCR applied to isolated microorganisms from the mash.

In situ product removal in fermentation systems: improved process performance and rational extractant selection.

PubMed

Dafoe, Julian T; Daugulis, Andrew J

2014-03-01

The separation of inhibitory compounds as they are produced in biotransformation and fermentation systems is termed in situ product removal (ISPR). This review examines recent ISPR strategies employing several classes of extractants including liquids, solids, gases, and combined extraction systems. Improvement through the simple application of an auxiliary phase are tabulated and summarized to indicate the breadth of recent ISPR activities. Studies within the past 5 years that have highlighted and have discussed "second phase" properties, and that have an effect on fermentation performance, are particular focus of this review. ISPR, as a demonstrably effective processing strategy, continues to be widely adopted as more applications are explored; however, focus on the properties of extractants and their rational selection based on first principle considerations will likely be key to successfully applying ISPR to more challenging target molecules.

Lauren Magnusson | NREL

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fermentation of an insoluble cellulosic substrate under continuous culture conditions, and that C. thermocellum lignocellulosic biomass Fermentation of waste green algal cell mass for hydrogen production Education M.S , 2005 Featured Publications "Continuous hydrogen production during fermentation of α-cellulose by

High efficiency cell-recycle continuous sodium gluconate production by Aspergillus niger using on-line physiological parameters association analysis to regulate feed rate rationally.

PubMed

Lu, Fei; Li, Chao; Wang, Zejian; Zhao, Wei; Chu, Ju; Zhuang, Yingping; Zhang, Siliang

2016-11-01

In this paper, a system of cell-recycle continuous fermentation for sodium gluconate (SG) production by Aspergillus niger (A. niger) was established. Based on initial continuous fermentation result (100.0h) with constant feed rate, an automatic feedback strategy to regulate feed rate using on-line physiological parameters (OUR and DO) was proposed and applied successfully for the first time in the improved continuous fermentation (240.5h). Due to less auxiliary time, highest SG production rate (31.05±0.29gL(-1)h(-1)) and highest yield (0.984±0.067molmol(-1)), overall SG production capacity (975.8±5.8gh(-1)) in 50-L fermentor of improved continuous fermentation increased more than 300.0% compared to that of batch fermentation. Improvement of mass transfer and dispersed mycelia morphology were the two major reasons responsible for the high SG production rate. This system had been successfully applied to industrial fermentation and SG production was greatly improved. Copyright © 2016 Elsevier Ltd. All rights reserved.

Adaptation of continuous biogas reactors operating under wet fermentation conditions to dry conditions with corn stover as substrate.

PubMed

Kakuk, Balázs; Kovács, Kornél L; Szuhaj, Márk; Rákhely, Gábor; Bagi, Zoltán

2017-08-01

Corn stover (CS) is the agricultural by-product of maize cultivation. Due to its high abundance and high energy content it is a promising substrate for the bioenergy sector. However, it is currently neglected in industrial scale biogas plants, because of its slow decomposition and hydrophobic character. To assess the maximum biomethane potential of CS, long-term batch fermentations were carried out with various substrate concentrations and particle sizes for 72 days. In separate experiments we adapted the biogas producing microbial community in wet fermentation arrangement first to the lignocellulosic substrate, in Continuous Stirred Tank Reactor (CSTR), then subsequently, by continuously elevating the feed-in concentration, to dry conditions in solid state fermenters (SS-AD). In the batch tests, the <10 mm fraction of the grinded and sieved CS was amenable for biogasification, but it required 10% more time to produce 90% of the total biomethane yield than the <2 mm sized fraction, although in the total yields there was no significant difference between the two size ranges. We also observed that increasing amount of substrate added to the fermentation lowered the specific methane yield. In the CSTR experiment, the daily substrate loading was gradually increased from 1 to 2 g vs /L/day until the system produced signs of overloading. Then the biomass was transferred to SS-AD reactors and the adaptation process was studied. Although the specific methane yields were lower in the SS-AD arrangement (177 mL CH 4 /g vs in CSTR vs. 105 mL in SS-AD), the benefits of process operational parameters, i.e. lower energy consumption, smaller reactor volume, digestate amount generated and simpler configuration, may compensate the somewhat lower yield. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Advanced modelling, monitoring, and process control of bioconversion systems

NASA Astrophysics Data System (ADS)

Schmitt, Elliott C.

Production of fuels and chemicals from lignocellulosic biomass is an increasingly important area of research and industrialization throughout the world. In order to be competitive with fossil-based fuels and chemicals, maintaining cost-effectiveness is critical. Advanced process control (APC) and optimization methods could significantly reduce operating costs in the biorefining industry. Two reasons APC has previously proven challenging to implement for bioprocesses include: lack of suitable online sensor technology of key system components, and strongly nonlinear first principal models required to predict bioconversion behavior. To overcome these challenges batch fermentations with the acetogen Moorella thermoacetica were monitored with Raman spectroscopy for the conversion of real lignocellulosic hydrolysates and a kinetic model for the conversion of synthetic sugars was developed. Raman spectroscopy was shown to be effective in monitoring the fermentation of sugarcane bagasse and sugarcane straw hydrolysate, where univariate models predicted acetate concentrations with a root mean square error of prediction (RMSEP) of 1.9 and 1.0 g L-1 for bagasse and straw, respectively. Multivariate partial least squares (PLS) models were employed to predict acetate, xylose, glucose, and total sugar concentrations for both hydrolysate fermentations. The PLS models were more robust than univariate models, and yielded a percent error of approximately 5% for both sugarcane bagasse and sugarcane straw. In addition, a screening technique was discussed for improving Raman spectra of hydrolysate samples prior to collecting fermentation data. Furthermore, a mechanistic model was developed to predict batch fermentation of synthetic glucose, xylose, and a mixture of the two sugars to acetate. The models accurately described the bioconversion process with an RMSEP of approximately 1 g L-1 for each model and provided insights into how kinetic parameters changed during dual substrate fermentation with diauxic growth. Model predictive control (MPC), an advanced process control strategy, is capable of utilizing nonlinear models and sensor feedback to provide optimal input while ensuring critical process constraints are met. Using the microorganism Saccharomyces cerevisiae, a commonly used microorganism for biofuel production, and work performed with M. thermoacetica, a nonlinear MPC was implemented on a continuous membrane cell-recycle bioreactor (MCRB) for the conversion of glucose to ethanol. The dilution rate was used to control the ethanol productivity of the system will maintaining total substrate conversion above the constraint of 98%. PLS multivariate models for glucose (RMSEP 1.5 g L-1) and ethanol (RMSEP 0.4 g L-1) were robust in predicting concentrations and a mechanistic kinetic model built accurately predicted continuous fermentation behavior. A setpoint trajectory, ranging from 2 - 4.5 g L-1 h-1 for productivity was closely tracked by the fermentation system using Raman measurements and an extended Kalman filter to estimate biomass concentrations. Overall, this work was able to demonstrate an effective approach for real-time monitoring and control of a complex fermentation system.

Fermentation of cucumbers brined with calcium chloride instead of sodium chloride.

PubMed

McFeeters, Roger F; Pérez-Díaz, Ilenys

2010-04-01

Waste water containing high levels of NaCl from cucumber fermentation tank yards is a continuing problem for the pickled vegetable industry. A major reduction in waste salt could be achieved if NaCl were eliminated from the cucumber fermentation process. The objectives of this project were to ferment cucumbers in brine containing CaCl(2) as the only salt, to determine the course of fermentation metabolism in the absence of NaCl, and to compare firmness retention of cucumbers fermented in CaCl(2) brine during subsequent storage compared to cucumbers fermented in brines containing both NaCl and CaCl(2) at concentrations typically used in commercial fermentations. The major metabolite changes during fermentation without NaCl were conversion of sugars in the fresh cucumbers primarily to lactic acid which caused pH to decrease to less than 3.5. This is the same pattern that occurs when cucumbers are fermented with NaCl as the major brining salt. Lactic acid concentration and pH were stable during storage and there was no detectable production of propionic acid or butyric acid that would indicate growth of spoilage bacteria. Firmness retention in cucumbers fermented with 100 to 300 mM CaCl(2) during storage at a high temperature (45 degrees C) was not significantly different from that obtained in fermented cucumbers with 1.03 M NaCl and 40 mM CaCl(2). In closed jars, cucumber fermentations with and without NaCl in the fermentation brine were similar both in the chemical changes caused by the fermentative microorganisms and in the retention of firmness in the fermented cucumbers.

Economically oriented process optimization in waste management.

PubMed

Maroušek, Josef

2014-06-01

A brief report on the development of novel apparatus is presented. It was verified in a commercial scale that a new concept of anaerobic fermentation followed by continuous pyrolysis is technically and economically feasible to manage previously enzymatically hydrolyzed waste haylage in huge volumes. The design of the concept is thoroughly described, documented in figures, and biochemically analyzed in detail. Assessment of the concept shows that subsequent pyrolysis of the anaerobically fermented residue allows among biogas to produce also high-quality biochar. This significantly improves the overall economy. In addition, it may be assumed that this applied research is consistent with previous theoretical assumptions stating that any kind of aerobic or anaerobic fermentation increases the microporosity of the biochar obtained.

Multi-stage Continuous Culture Fermentation of Glucose-Xylose Mixtures to Fuel Ethanol using Genetically Engineered Saccharomyces cerevisiae 424A

EPA Science Inventory

Multi-stage continuous (chemostat) culture fermentation (MCCF) with variable fermentor volumes was carried out to study utilizing glucose and xylose for ethanol production by means of mixed sugar fermentation (MSF). Variable fermentor volumes were used to enable enhanced sugar u...

Cell growth behaviors of Clostridium acetobutylicum in a pervaporation membrane bioreactor for butanol fermentation.

PubMed

Yao, Peina; Xiao, Zeyi; Chen, Chunyan; Li, Weijia; Deng, Qing

2016-01-01

Acetone-butanol-ethanol fermentation using Clostridium acetobutylicum was studied in the continuous and closed-circulating fermentation (CCCF) system. The experiment lasting for 192 H was carried out by integrating fermentation with in situ pervaporation. In the entire process, the cell growth profile took place in the following two phases: the logarithmic phase during early 28 H and the linear phase from 130 to 150 H. This was a unique characteristic compared with the curve of traditional fermentation, and the fitting equations of two growth phases were obtained by Origin software according to the kinetic model of cell growth. Besides, the kinetic parameters that include the butanol yield, maximum specific growth rate, average specific formation rate, and volumetric productivity of butanol were measured as 0.19 g g(-1) , 0.345 H(-1) , 0.134 H(-1) and 0.23 g L(-1)  H(-1) , respectively. The C. acetobutylicum in the CCCF system showed good adaptability and fermentation performance, and the prolonged fermentation period and high production were also the main advantages of CCCF technology. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

Continuous production of butanol from starch-based packing peanuts.

PubMed

Ezeji, Thaddeus C; Groberg, Marisa; Qureshi, Nasib; Blaschek, Hans P

2003-01-01

Acetone, butanol, ethanol (ABE, or solvents) were produced from starch-based packing peanuts in batch and continuous reactors. In a batch reactor, 18.9 g/L of total ABE was produced from 80 g/L packing peanuts in 110 h of fermentation. The initial and final starch concentrations were 69.6 and 11.1 g/L, respectively. In this fermentation, ABE yield and productivity of 0.32 and 0.17 g/(L h) were obtained, respectively. Compared to the batch fermentation, continuous fermentation of 40 g/L of starchbased packing peanuts in P2 medium resulted in a maximum solvent production of 8.4 g/L at a dilution rate of 0.033 h-1. This resulted in a productivity of 0.27 g/(L h). However, the reactor was not stable and fermentation deteriorated with time. Continuous fermentation of 35 g/L of starch solution resulted in a similar performance. These studies were performed in a vertical column reactor using Clostridium beijerinckii BA101 and P2 medium. It is anticipated that prolonged exposure of culture to acrylamide, which is formed during boiling/autoclaving of starch, affects the fermentation negatively.

Development of a High Temperature Microbial Fermentation Processfor Butanol Production

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

Jeor, Jeffery D.; Reed, David W.; Daubaras, Dayna L.

2016-06-01

Transforming renewable biomass into cost competitive high-performance biofuels and bioproducts is key to US energy security. Butanol production by microbial fermentation and chemical conversion to polyolefins, elastomers, drop-in jet or diesel fuel, and other chemicals is a promising solution. A high temperature fermentation process can facilitate butanol recovery up to 40%, by using gas stripping. Other benefits of fermentation at high temperatures are optimal hydrolysis rates in the saccharification of biomass which leads to maximized butanol production, decrease in energy costs associated with reactor cooling and capital cost associated with reactor design, and a decrease in contamination and cost formore » maintaining a sterile environment. Butanol stripping at elevated temperatures gives higher butanol production through constant removal and continuous fermentation. We describe methods used in an attempt to genetically prepare Geobacillus caldoxylosiliticus for insertion of a butanol pathway. Methods used were electroporation of electrocompetent cells, ternary conjugation with E. coli, and protoplast fusion.« less

Performance of continuous stirred tank reactor (CSTR) on fermentative biohydrogen production from melon waste

NASA Astrophysics Data System (ADS)

Cahyari, K.; Sarto; Syamsiah, S.; Prasetya, A.

2016-11-01

This research was meant to investigate performance of continuous stirred tank reactor (CSTR) as bioreactor for producing biohydrogen from melon waste through dark fermentation method. Melon waste are commonly generated from agricultural processing stages i.e. cultivation, post-harvesting, industrial processing, and transportation. It accounted for more than 50% of total harvested fruit. Feedstock of melon waste was fed regularly to CSTR according to organic loading rate at value 1.2 - 3.6 g VS/ (l.d). Optimum condition was achieved at OLR 2.4 g VS/ (l.d) with the highest total gas volume 196 ml STP. Implication of higher OLR value is reduction of total gas volume due to accumulation of acids (pH 4.0), and lower substrate volatile solid removal. In summary, application of this method might valorize melon waste and generates renewable energy sources.

Performance assessment of two-stage anaerobic digestion of kitchen wastes.

PubMed

Bo, Zhang; Pin-Jing, He

2014-01-01

This study is aimed at investigating the performance of the two-phase anaerobic digestion of kitchen wastes in a lab-scale setup. The semi-continuous experiment showed that the two-phase anaerobic digestion of kitchen wastes had a bioconversion rate of 83%, biogas yield of 338 mL x (g chemical oxygen demand (COD))(-1) and total solid conversion of 63% when the entire two-phase anaerobic digestion process was subjected to an organic loading rate (OLR) of 10.7 g x (L d)(-1). In the hydrolysis-acidogenesis process, the efficiency of solubilization decreased from 72.6% to 41.1%, and the acidogenesis efficiency decreased from 31.8% to 17.8% with an increase in the COD loading rate. On the other hand, the performance of the subsequent methanogenic process was not susceptible to the increase in the feeding COD loading rate in the hydrolysis-acidogenesis stage. Lactic acid was one of the main fermentation products, accounting for over 40% of the total soluble COD in the fermentation liquid. The batch experiments indicated that the lactic acid was the earliest predominant fermentation product, and distributions of fermentation products were pH dependent. Results showed that increasing the feeding OLR of kitchen wastes made the two-stage anaerobic digestion process more effective. Moreover, there was a potential improvement in the performance of anaerobic digestion of kitchen wastes with a corresponding improvement in the hydrolysis process.

A novel solid state fermentation coupled with gas stripping enhancing the sweet sorghum stalk conversion performance for bioethanol

PubMed Central

2014-01-01

Background Bioethanol production from biomass is becoming a hot topic internationally. Traditional static solid state fermentation (TS-SSF) for bioethanol production is similar to the traditional method of intermittent operation. The main problems of its large-scale intensive production are the low efficiency of mass and heat transfer and the high ethanol inhibition effect. In order to achieve continuous production and high conversion efficiency, gas stripping solid state fermentation (GS-SSF) for bioethanol production from sweet sorghum stalk (SSS) was systematically investigated in the present study. Results TS-SSF and GS-SSF were conducted and evaluated based on different SSS particle thicknesses under identical conditions. The ethanol yield reached 22.7 g/100 g dry SSS during GS-SSF, which was obviously higher than that during TS-SSF. The optimal initial gas stripping time, gas stripping temperature, fermentation time, and particle thickness of GS-SSF were 10 h, 35°C, 28 h, and 0.15 cm, respectively, and the corresponding ethanol stripping efficiency was 77.5%. The ethanol yield apparently increased by 30% with the particle thickness decreasing from 0.4 cm to 0.05 cm during GS-SSF. Meanwhile, the ethanol yield increased by 6% to 10% during GS-SSF compared with that during TS-SSF under the same particle thickness. The results revealed that gas stripping removed the ethanol inhibition effect and improved the mass and heat transfer efficiency, and hence strongly enhanced the solid state fermentation (SSF) performance of SSS. GS-SSF also eliminated the need for separate reactors and further simplified the bioethanol production process from SSS. As a result, a continuous conversion process of SSS and online separation of bioethanol were achieved by GS-SSF. Conclusions SSF coupled with gas stripping meet the requirements of high yield and efficient industrial bioethanol production. It should be a novel bioconversion process for bioethanol production from SSS biomass. PMID:24713041

Effects of initial moisture content of Korean traditional wheat-based fermentation starter nuruk on microbial abundance and diversity.

PubMed

Bal, Jyotiranjan; Yun, Suk-Hyun; Yeo, Soo-Hwan; Kim, Jung-Mi; Kim, Beom-Tae; Kim, Dae-Hyuk

2017-03-01

The brewing of makgeolli, one of Korea's most popular alcoholic beverages that is gaining popularity globally, is facilitated by nuruk, a traditional Korean cereal starter. The nuruk microbiome greatly influences the fermentation process as well as the nutritional, hygienic, and aromatic qualities of the product. This study is a continuation of our efforts to examine nuruk biodiversity at a depth previously unattainable. In this study, microfloral dynamics in wheat-based nuruk C, composed of traditional ingredients such as barley, green gram, and wheat and fermented under various internal moisture contents of 20% (C20), 26% (C26), and 30% (C30), was evaluated using 454 pyrosequencing during the 30-day fermentation process. Rarefaction analysis and alpha diversity parameters indicated adequate sampling. C20 showed the greatest fungal richness and diversity, C20 and C26 exhibited similar bacterial richness and diversity, while C30 had low fungal and bacterial richness. Fungal taxonomic assignments revealed that the initial moisture content caused selective enrichment of Aspergillus candidus with a decreasing trend during fermentation, whereas Saccharomycetales sp. exhibited increasing relative abundance with increasing moisture content from day 6 of the fermentation process. Depending on initial moisture level, changes in bacterial communities were also observed in the genera Streptomyces, Bacillus, and Staphylococcus, with decreasing trends whereas Saccharopolyspora exhibited a sigmoidal trend with the highest abundance in C26. These findings demonstrate the possible impact of initial moisture content of nuruk on microfloral richness, diversity, and dynamics; this study is thus a step toward our ultimate goal of enhancing the quality of nuruk.

Continuous butanol fermentation and feed starch retrogradation: butanol fermentation sustainability using Clostridium beijerinckii BA101.

PubMed

Ezeji, T C; Qureshi, N; Blaschek, H P

2005-01-26

Use of starch solution as feed for butanol bioconversion processes employing Clostridium beijerinckii BA101 may have added economic advantage over the use of glucose. Acetone butanol ethanol (ABE) was produced from 30 gL(-1) starch solution using a continuous process. The bioreactor was fed at a dilution rate of 0.02 h(-1) and starch solution/feed volume (3 L) was replaced every 72 h. The continuous reactor fed with cornstarch solution (feed temperature 19 degrees C) produced approximately 6.0 gL(-1) total ABE. Increasing the feed storage temperature to 37 degrees C improved ABE production to 7.2 gL(-1) suggesting that retrogradation was occurring more rapidly at 19 degrees C. In both these cases the fermentation drifted toward acid production after approximately 260 h, consistent with the retrogradation of starch overtime. The use of soluble starch, which is less prone to retrogradation, resulted in the production of 9.9 gL(-1) ABE at 37 degrees C feed storage temperature, as compared to 7.2 gL(-1) ABE when cornstarch was used. It should be noted that gelatinized starch retrogradation takes place after sterilization and prior to use of the feed medium, and does not occur during long-term storage of the raw corn material in the months leading up to processing. The degree of hydrolysis of gelatinized starch decreased from 68.8 to 56.2% in 3 days when stored at 37 degrees C. Soluble starch which does not retrograde demonstrated no change in the degree of hydrolysis.

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

PubMed

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

2012-02-01

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

Paraformaldehyde-Resistant Starch-Fermenting Bacteria in “Starch-Base” Drilling Mud

PubMed Central

Myers, G. E.

1962-01-01

Starch-fermenting bacteria were found in each of 12 samples of nonfermenting starch-base drilling mud examined. Of the 12 samples, 3 contained very active starch-fermenting gram-positive spore-bearing bacilli closely resembling Bacillus subtilis. Similar active starch-fermenting bacteria were found in fermenting starch-base drilling mud and in corn starch and slough water used to prepare such mud. The active starch-fermenting microorganisms completely hydrolyzed 1% (w/v) corn starch within 24 hr at 37.5 C. The active starch-fermenting bacteria isolated from fermenting drilling mud were capable of surviving 12 hr of continuous exposure to 0.1% (w/w) paraformaldehyde or 1 hr of continuous exposure to 0.5% (w/w) paraformaldehyde, with no diminution in starch-fermenting ability. The same organisms fermented starch after 3 hr of continuous exposure to 0.5% (w/w) paraformaldehyde, but not after 4 hr of exposure. The phenomenon of rapid disappearance of paraformaldehyde from fermenting drilling mud was observed in the laboratory using a modified sodium sulfite test. Paraformaldehyde, initially present in a concentration of 0.192 lb per barrel of mud, completely disappeared in 9 hr at 22 to 23 C. A significant decrease in paraformaldehyde concentration was detected 0.5 hr after preparation of the mud. It is suggested that the presence of relatively high concentrations of ammonia and chloride in the mud may facilitate the disappearance of paraformaldehyde. The failure of 0.1% (w/w) paraformaldehyde to inhibit the strong starch-fermenting microorganisms isolated from fermenting drilling mud, and the rapid disappearance of paraformaldehyde from the mud, explains the fermentation of starch which occurred in this mud, despite the addition of paraformaldehyde. PMID:13936949

Global behavior analysis for stochastic system of 1,3-PD continuous fermentation

NASA Astrophysics Data System (ADS)

Zhu, Xi; Kliemann, Wolfgang; Li, Chunfa; Feng, Enmin; Xiu, Zhilong

2017-12-01

Global behavior for stochastic system of continuous fermentation in glycerol bio-dissimilation to 1,3-propanediol by Klebsiella pneumoniae is analyzed in this paper. This bioprocess cannot avoid the stochastic perturbation caused by internal and external disturbance which reflect on the growth rate. These negative factors can limit and degrade the achievable performance of controlled systems. Based on multiplicity phenomena, the equilibriums and bifurcations of the deterministic system are analyzed. Then, a stochastic model is presented by a bounded Markov diffusion process. In order to analyze the global behavior, we compute the control sets for the associated control system. The probability distributions of relative supports are also computed. The simulation results indicate that how the disturbed biosystem tend to stationary behavior globally.

Genome-wide study of the adaptation of Saccharomyces cerevisiae to the early stages of wine fermentation.

PubMed

Novo, Maite; Mangado, Ana; Quirós, Manuel; Morales, Pilar; Salvadó, Zoel; Gonzalez, Ramon

2013-01-01

This work was designed to identify yeast cellular functions specifically affected by the stress factors predominating during the early stages of wine fermentation, and genes required for optimal growth under these conditions. The main experimental method was quantitative fitness analysis by means of competition experiments in continuous culture of whole genome barcoded yeast knockout collections. This methodology allowed the identification of haploinsufficient genes, and homozygous deletions resulting in growth impairment in synthetic must. However, genes identified as haploproficient, or homozygous deletions resulting in fitness advantage, were of little predictive power concerning optimal growth in this medium. The relevance of these functions for enological performance of yeast was assessed in batch cultures with single strains. Previous studies addressing yeast adaptation to winemaking conditions by quantitative fitness analysis were not specifically focused on the proliferative stages. In some instances our results highlight the importance of genes not previously linked to winemaking. In other cases they are complementary to those reported in previous studies concerning, for example, the relevance of some genes involved in vacuolar, peroxisomal, or ribosomal functions. Our results indicate that adaptation to the quickly changing growth conditions during grape must fermentation require the function of different gene sets in different moments of the process. Transport processes and glucose signaling seem to be negatively affected by the stress factors encountered by yeast in synthetic must. Vacuolar activity is important for continued growth during the transition to stationary phase. Finally, reduced biogenesis of peroxisomes also seems to be advantageous. However, in contrast to what was described for later stages, reduced protein synthesis is not advantageous for the early (proliferative) stages of the fermentation process. Finally, we found adenine and lysine to be in short supply for yeast growth in some natural grape musts.

Investigation of the performance of fermentation processes using a mathematical model including effects of metabolic bottleneck and toxic product on cells.

PubMed

Sriyudthsak, Kansuporn; Shiraishi, Fumihide

2010-11-01

A number of recent research studies have focused on theoretical and experimental investigation of a bottleneck in a metabolic reaction network. However, there is no study on how the bottleneck affects the performance of a fermentation process when a product is highly toxic and remarkably influences the growth and death of cells. The present work therefore studies the effect of bottleneck on product concentrations under different product toxicity conditions. A generalized bottleneck model in a fed-batch fermentation is constructed including both the bottleneck and the product influences on cell growth and death. The simulation result reveals that when the toxic product strongly influences the cell growth and death, the final product concentration is hardly changed even if the bottleneck is removed, whereas it is markedly changed by the degree of product toxicity. The performance of an ethanol fermentation process is also discussed as a case example to validate this result. In conclusion, when the product is highly toxic, one cannot expect a significant increase in the final product concentration even if removing the bottleneck; rather, it may be more effective to somehow protect the cells so that they can continuously produce the product. Copyright © 2010 Elsevier Inc. All rights reserved.

Recent advances to improve fermentative butanol production: genetic engineering and fermentation technology.

PubMed

Zheng, Jin; Tashiro, Yukihiro; Wang, Qunhui; Sonomoto, Kenji

2015-01-01

Butanol has recently attracted attention as an alternative biofuel because of its various advantages over other biofuels. Many researchers have focused on butanol fermentation with renewable and sustainable resources, especially lignocellulosic materials, which has provided significant progress in butanol fermentation. However, there are still some drawbacks in butanol fermentation in terms of low butanol concentration and productivity, high cost of feedstock and product inhibition, which makes butanol fermentation less competitive than the production of other biofuels. These hurdles are being resolved in several ways. Genetic engineering is now available for improving butanol yield and butanol ratio through overexpression, knock out/down, and insertion of genes encoding key enzymes in the metabolic pathway of butanol fermentation. In addition, there are also many strategies to improve fermentation technology, such as multi-stage continuous fermentation, continuous fermentation integrated with immobilization and cell recycling, and the inclusion of additional organic acids or electron carriers to change metabolic flux. This review focuses on the most recent advances in butanol fermentation especially from the perspectives of genetic engineering and fermentation technology. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Application of low-cost algal nitrogen source feeding in fuel ethanol production using high gravity sweet potato medium.

PubMed

Shen, Yu; Guo, Jin-Song; Chen, You-Peng; Zhang, Hai-Dong; Zheng, Xu-Xu; Zhang, Xian-Ming; Bai, Feng-Wu

2012-08-31

Protein-rich bloom algae biomass was employed as nitrogen source in fuel ethanol fermentation using high gravity sweet potato medium containing 210.0 g l(-1) glucose. In batch mode, the fermentation could not accomplish even in 120 h without any feeding of nitrogen source. While, the feeding of acid-hydrolyzed bloom algae powder (AHBAP) notably promoted fermentation process but untreated bloom algae powder (UBAP) was less effective than AHBAP. The fermentation times were reduced to 96, 72, and 72 h if 5.0, 10.0, and 20.0 g l(-1) AHBAP were added into medium, respectively, and the ethanol yields and productivities increased with increasing amount of feeding AHBAP. The continuous fermentations were performed in a three-stage reactor system. Final concentrations of ethanol up to 103.2 and 104.3 g l(-1) with 4.4 and 5.3 g l(-1) residual glucose were obtained using the previously mentioned medium feeding with 20.0 and 30.0 g l(-1) AHBAP, at dilution rate of 0.02 h(-1). Notably, only 78.5 g l(-1) ethanol and 41.6 g l(-1) residual glucose were obtained in the comparative test without any nitrogen source feeding. Amino acids analysis showed that approximately 67% of the protein in the algal biomass was hydrolyzed and released into the medium, serving as the available nitrogen nutrition for yeast growth and metabolism. Both batch and continuous fermentations showed similar fermentation parameters when 20.0 and 30.0 g l(-1) AHBAP were fed, indicating that the level of available nitrogen in the medium should be limited, and an algal nitrogen source feeding amount higher than 20.0 g l(-1) did not further improve the fermentation performance. Copyright © 2012 Elsevier B.V. All rights reserved.

Enhanced Fermentative Hydrogen and Methane Production from an Inhibitory Fruit-Flavored Medium with Membrane-Encapsulated Cells

PubMed Central

Akinbomi, Julius; Wikandari, Rachman; Taherzadeh, Mohammad J.

2015-01-01

This study focused on the possibility of improving fermentative hydrogen and methane production from an inhibitory fruit-flavored medium using polyvinylidene fluoride (PVDF) membrane-encapsulated cells. Hexanal, myrcene, and octanol, which are naturally produced in fruits such as apple, grape, mango, orange, strawberry, and plum, were investigated. Batch and semi-continuous fermentation processes at 55 °C were carried out. Presence of 5 g/L of myrcene, octanol, and hexanal resulted in no methane formation by fermenting bacteria, while encapsulated cells in the membranes resulted in successful fermentation with 182, 111, and 150 mL/g COD of methane, respectively. The flavor inhibitions were not serious on hydrogen-producing bacteria. With free cells in the presence of 5 g/L (final concentration) of hexanal-, myrcene-, and octanol-flavored media, average daily yields of 68, 133, and 88 mL/g COD of hydrogen, respectively, were obtained. However, cell encapsulation further improved these hydrogen yields to 189, 179, and 198 mL/g COD. The results from this study indicate that the yields of fermentative hydrogen and methane productions from an inhibitory medium could be improved using encapsulated cells. PMID:26501329

Metabolite profiling of the fermentation process of "yamahai-ginjo-shikomi" Japanese sake.

PubMed

Tatsukami, Yohei; Morisaka, Hironobu; Aburaya, Shunsuke; Aoki, Wataru; Kohsaka, Chihiro; Tani, Masafumi; Hirooka, Kiyoo; Yamamoto, Yoshihiro; Kitaoka, Atsushi; Fujiwara, Hisashi; Wakai, Yoshinori; Ueda, Mitsuyoshi

2018-01-01

Sake is a traditional Japanese alcoholic beverage prepared by multiple parallel fermentation of rice. The fermentation process of "yamahai-ginjo-shikomi" sake is mainly performed by three microbes, Aspergillus oryzae, Saccharomyces cerevisiae, and Lactobacilli; the levels of various metabolites fluctuate during the fermentation of sake. For evaluation of the fermentation process, we monitored the concentration of moderate-sized molecules (m/z: 200-1000) dynamically changed during the fermentation process of "yamahai-ginjo-shikomi" Japanese sake. This analysis revealed that six compounds were the main factors with characteristic differences in the fermentation process. Among the six compounds, four were leucine- or isoleucine-containing peptides and the remaining two were predicted to be small molecules. Quantification of these compounds revealed that their quantities changed during the month of fermentation process. Our metabolomic approach revealed the dynamic changes observed in moderate-sized molecules during the fermentation process of sake, and the factors found in this analysis will be candidate molecules that indicate the progress of "yamahai-ginjo-shikomi" sake fermentation.

Enhanced coproduction of hydrogen and methane from cornstalks by a three-stage anaerobic fermentation process integrated with alkaline hydrolysis.

PubMed

Cheng, Xi-Yu; Liu, Chun-Zhao

2012-01-01

A three-stage anaerobic fermentation process including H(2) fermentation I, H(2) fermentation II, methane fermentation was developed for the coproduction of hydrogen and methane from cornstalks. Hydrogen production from cornstalks using direct microbial conversion by Clostridium thermocellum 7072 was markedly enhanced in the two-stage thermophilic hydrogen fermentation process integrated with alkaline treatment. The highest total hydrogen yield from cornstalks in the two-stage fermentation process reached 74.4 mL/g-cornstalk. The hydrogen fermentation effluents and alkaline hydrolyzate were further used for methane fermentation by anaerobic granular sludge, and the total methane yield reached 205.8 mL/g-cornstalk. The total energy recovery in the three-stage anaerobic fermentation process integrated with alkaline hydrolysis reached 70.0%. Copyright © 2011 Elsevier Ltd. All rights reserved.

Continuous citric acid production in repeated-fed batch fermentation by Aspergillus niger immobilized on a new porous foam.

PubMed

Yu, Bin; Zhang, Xin; Sun, Wenjun; Xi, Xun; Zhao, Nan; Huang, Zichun; Ying, Zhuojun; Liu, Li; Liu, Dong; Niu, Huanqing; Wu, Jinglan; Zhuang, Wei; Zhu, Chenjie; Chen, Yong; Ying, Hanjie

2018-06-20

The efficiency of current methods for industrial production of citric acid is limited. To achieve continuous citric acid production with enhanced yield and reduced cost, immobilized fermentation was employed in an Aspergillus niger 831 repeated fed-batch fermentation system. We developed a new type of material (PAF201), which was used as a carrier for the novel adsorption immobilization system. Hydrophobicity, pore size and concentration of carriers were researched in A. niger immobilization. The efficiency of the A. niger immobilization process was analyzed by scanning electron microscopy. Then eight-cycle repeated fed-batch cultures for citric acid production were carried out over 600 h, which showed stable production with maximum citric acid concentrations and productivity levels of 162.7 g/L and 2.26 g L -1  h -1 , respectively. Compared with some other literatures about citric acid yield, PAF201 immobilization system is 11.3% higher than previous results. These results indicated that use of the new adsorption immobilization system could greatly improve citric acid productivity in repeated fed-batch fermentation. Moreover, these results could provide a guideline for A.niger or other filamentous fungi immobilization in industry. Copyright © 2018 Elsevier B.V. All rights reserved.

Fermentation process improvement of a Chinese traditional food: soybean residue cake.

PubMed

Yao, Yingzheng; Pan, Siyi; Wang, Kexing; Xu, Xiaoyun

2010-09-01

Fermentation process improvement of soybean residue cake, a Chinese traditional fermented food, and its physicochemical analysis during fermentation were studied. One of the dominant strains in the fermentation was isolated and identified as Mucor racemosus Fresenius. The fermentation process was improved by subsection fermentation. The crude protein content decreased from 19.95 ± 0.03% in the raw soybean residue to 16.85 ± 0.10% in the fermented products, and the formaldehyde nitrogen content increased from 0.068 ± 0.004% to 0.461 ± 0.022% in final fermented cakes. Hardness of samples significantly (P < 0.05) increased whereas springiness, cohesiveness, and resilience significantly (P < 0.05) decreased with increasing fermentation time, respectively. Microstructure observations showed obvious change of the surface of cake samples during the fermentation process. During the soybean processing, it will produce plenty of by-products, and the most part of them is soybean residue. The discarded soybean residue causes economic loss. Fortunately, we can obtain nutritious and delicious fermented soybean residue cakes by fermenting soybean residue as raw material.

A combined approach of generalized additive model and bootstrap with small sample sets for fault diagnosis in fermentation process of glutamate.

PubMed

Liu, Chunbo; Pan, Feng; Li, Yun

2016-07-29

Glutamate is of great importance in food and pharmaceutical industries. There is still lack of effective statistical approaches for fault diagnosis in the fermentation process of glutamate. To date, the statistical approach based on generalized additive model (GAM) and bootstrap has not been used for fault diagnosis in fermentation processes, much less the fermentation process of glutamate with small samples sets. A combined approach of GAM and bootstrap was developed for the online fault diagnosis in the fermentation process of glutamate with small sample sets. GAM was first used to model the relationship between glutamate production and different fermentation parameters using online data from four normal fermentation experiments of glutamate. The fitted GAM with fermentation time, dissolved oxygen, oxygen uptake rate and carbon dioxide evolution rate captured 99.6 % variance of glutamate production during fermentation process. Bootstrap was then used to quantify the uncertainty of the estimated production of glutamate from the fitted GAM using 95 % confidence interval. The proposed approach was then used for the online fault diagnosis in the abnormal fermentation processes of glutamate, and a fault was defined as the estimated production of glutamate fell outside the 95 % confidence interval. The online fault diagnosis based on the proposed approach identified not only the start of the fault in the fermentation process, but also the end of the fault when the fermentation conditions were back to normal. The proposed approach only used a small sample sets from normal fermentations excitements to establish the approach, and then only required online recorded data on fermentation parameters for fault diagnosis in the fermentation process of glutamate. The proposed approach based on GAM and bootstrap provides a new and effective way for the fault diagnosis in the fermentation process of glutamate with small sample sets.

Investigation of gas stripping and pervaporation for improved feasibility of two-stage butanol production process.

PubMed

Setlhaku, Mpho; Heitmann, Sebastian; Górak, Andrzej; Wichmann, Rolf

2013-05-01

Gas stripping and pervaporation are investigated for butanol recovery in a two-stage acetone-butanol-ethanol (ABE) fermentation process. The first stage is operated in a continuous mode and the second stage as a fed-batch. Gas stripping coupled to the second stage and operated intermittently enabled additional glucose feeding in the second stage and up to 59 g/L butanol and 73 g/L total ABE solvents in the condensate. Concentration of 167 g/L butanol and 269 g/L ABE in the permeate was measured in ex situ pervaporation experiments using a PDMS membrane at temperature of 37 °C and pressure of 10mbars. The "operating window" tool is introduced to evaluate the feasibility of the existing ABE fermentations operated as continuous with cell recycle, as two-stages, with biomass immobilization or with integrated product removal. This tool enables the identification of the most favorable process configuration, which is the combination of cell immobilization and integrated product removal. Copyright © 2013 Elsevier Ltd. All rights reserved.

Influence of aeration during propagation of pitching yeast on fermentation and beer flavor.

PubMed

Cheong, Chul; Wackerbauer, Karl; Kang, Soon Ah

2007-02-01

The effect of yeast propagated at different aeration conditions on yeast physiology, fermentation ability, and beer quality was investigated using three strains of Saccharomyces cerevisiae. It was shown that yeast cells grown under continuous aeration conditions during propagation were almost two times higher as compared with discontinuous aeration conditions. The maximum of cell growth of all samples reached between 36 h and 48 h. The concentration of trehalose was increased under continuous aerated yeasts, whereas glycogen was decreased. It was also observed that the concentration of glycogen and trehalose in yeast cells had no direct effect on subsequent fermentation ability. The effect of yeast propagated under different aeration conditions on subsequent fermentation ability was different from yeast strains, in which the influence will be most pronounced at the first fermentation. Later, the yeasts might regain its original characteristics in the following fermentations. Generally, continuously propagated yeast had a positive effect on beer quality in subsequent fermentation. Hence, the concentration of aroma compounds obtained with yeast propagated under 6 1/h for 48 h aeration was lower than those grown under other aeration conditions in the bottom yeasts; in particular, the amounts of phenylethyl alcohol, ester, and fatty acids were decreased.

Scaleable production and separation of fermentation-derived acetic acid. Final CRADA report.

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

Snyder, S. W.; Energy Systems

2010-02-08

Half of U.S. acetic acid production is used in manufacturing vinyl acetate monomer (VAM) and is economical only in very large production plants. Nearly 80% of the VAM is produced by methanol carbonylation, which requires high temperatures and exotic construction materials and is energy intensive. Fermentation-derived acetic acid production allows for small-scale production at low temperatures, significantly reducing the energy requirement of the process. The goal of the project is to develop a scaleable production and separation process for fermentation-derived acetic acid. Synthesis gas (syngas) will be fermented to acetic acid, and the fermentation broth will be continuously neutralized withmore » ammonia. The acetic acid product will be recovered from the ammonium acid broth using vapor-based membrane separation technology. The process is summarized in Figure 1. The two technical challenges to success are selecting and developing (1) microbial strains that efficiently ferment syngas to acetic acid in high salt environments and (2) membranes that efficiently separate ammonia from the acetic acid/water mixture and are stable at high enough temperature to facilitate high thermal cracking of the ammonium acetate salt. Fermentation - Microbial strains were procured from a variety of public culture collections (Table 1). Strains were incubated and grown in the presence of the ammonium acetate product and the fastest growing cultures were selected and incubated at higher product concentrations. An example of the performance of a selected culture is shown in Figure 2. Separations - Several membranes were considered. Testing was performed on a new product line produced by Sulzer Chemtech (Germany). These are tubular ceramic membranes with weak acid functionality (see Figure 3). The following results were observed: (1) The membranes were relatively fragile in a laboratory setting; (2) Thermally stable {at} 130 C in hot organic acids; (3) Acetic acid rejection > 99%; and (4) Moderate ammonia flux. The advantages of producing acetic acid by fermentation include its appropriateness for small-scale production, lower cost feedstocks, low energy membrane-based purification, and lower temperature and pressure requirements. Potential energy savings of using fermentation are estimated to be approximately 14 trillion Btu by 2020 from a reduction in natural gas use. Decreased transportation needs with regional plants will eliminate approximately 200 million gallons of diesel consumption, for combined savings of 45 trillion Btu. If the fermentation process captures new acetic acid production, savings could include an additional 5 trillion Btu from production and 7 trillion Btu from transportation energy.« less

Bioethanol production from the nutrient stress-induced microalga Chlorella vulgaris by enzymatic hydrolysis and immobilized yeast fermentation.

PubMed

Kim, Kyoung Hyoun; Choi, In Seong; Kim, Ho Myeong; Wi, Seung Gon; Bae, Hyeun-Jong

2014-02-01

The microalga Chlorella vulgaris is a potential feedstock for bioenergy due to its rapid growth, carbon dioxide fixation efficiency, and high accumulation of lipids and carbohydrates. In particular, the carbohydrates in microalgae make them a candidate for bioethanol feedstock. In this study, nutrient stress cultivation was employed to enhance the carbohydrate content of C. vulgaris. Nitrogen limitation increased the carbohydrate content to 22.4% from the normal content of 16.0% on dry weight basis. In addition, several pretreatment methods and enzymes were investigated to increase saccharification yields. Bead-beating pretreatment increased hydrolysis by 25% compared with the processes lacking pretreatment. In the enzymatic hydrolysis process, the pectinase enzyme group was superior for releasing fermentable sugars from carbohydrates in microalgae. In particular, pectinase from Aspergillus aculeatus displayed a 79% saccharification yield after 72h at 50°C. Using continuous immobilized yeast fermentation, microalgal hydrolysate was converted into ethanol at a yield of 89%. Copyright © 2013 Elsevier Ltd. All rights reserved.

Metabolite profiling of the fermentation process of "yamahai-ginjo-shikomi" Japanese sake

PubMed Central

Tatsukami, Yohei; Morisaka, Hironobu; Aburaya, Shunsuke; Aoki, Wataru; Kohsaka, Chihiro; Tani, Masafumi; Hirooka, Kiyoo; Yamamoto, Yoshihiro; Kitaoka, Atsushi; Fujiwara, Hisashi; Wakai, Yoshinori

2018-01-01

Sake is a traditional Japanese alcoholic beverage prepared by multiple parallel fermentation of rice. The fermentation process of “yamahai-ginjo-shikomi” sake is mainly performed by three microbes, Aspergillus oryzae, Saccharomyces cerevisiae, and Lactobacilli; the levels of various metabolites fluctuate during the fermentation of sake. For evaluation of the fermentation process, we monitored the concentration of moderate-sized molecules (m/z: 200–1000) dynamically changed during the fermentation process of “yamahai-ginjo-shikomi” Japanese sake. This analysis revealed that six compounds were the main factors with characteristic differences in the fermentation process. Among the six compounds, four were leucine- or isoleucine-containing peptides and the remaining two were predicted to be small molecules. Quantification of these compounds revealed that their quantities changed during the month of fermentation process. Our metabolomic approach revealed the dynamic changes observed in moderate-sized molecules during the fermentation process of sake, and the factors found in this analysis will be candidate molecules that indicate the progress of “yamahai-ginjo-shikomi” sake fermentation. PMID:29298316

Fungal solid state fermentation on agro-industrial wastes for acid wastewater decolorization in a continuous flow packed-bed bioreactor.

PubMed

Iandolo, Donata; Amore, Antonella; Birolo, Leila; Leo, Gabriella; Olivieri, Giuseppe; Faraco, Vincenza

2011-08-01

This study was aimed at developing a process of solid state fermentation (SSF) with the fungi Pleurotus ostreatus and Trametes versicolor on apple processing residues for wastewater decolorization. Both fungi were able to colonize apple residues without any addition of nutrients, material support or water. P. ostreatus produced the highest levels of laccases (up to 9U g(-1) of dry matter) and xylanases (up to 80U g(-1) of dry matter). A repeated batch decolorization experiment was set up with apple residues colonized by P. ostreatus, achieving 50% decolorization and 100% detoxification after 24h, and, adding fresh wastewater every 24h, a constant decolorization of 50% was measured for at least 1 month. A continuous decolorization experiment was set up by a packed-bed reactor based on colonized apple residues achieving a performance of 100mg dye L(-1)day(-1) at a retention time of 50h. Copyright © 2011 Elsevier Ltd. All rights reserved.

Improving ethanol productivity through self-cycling fermentation of yeast: a proof of concept.

PubMed

Wang, Jie; Chae, Michael; Sauvageau, Dominic; Bressler, David C

2017-01-01

The cellulosic ethanol industry has developed efficient strategies for converting sugars obtained from various cellulosic feedstocks to bioethanol. However, any further major improvements in ethanol productivity will require development of novel and innovative fermentation strategies that enhance incumbent technologies in a cost-effective manner. The present study investigates the feasibility of applying self-cycling fermentation (SCF) to cellulosic ethanol production to elevate productivity. SCF is a semi-continuous cycling process that employs the following strategy: once the onset of stationary phase is detected, half of the broth volume is automatically harvested and replaced with fresh medium to initiate the next cycle. SCF has been shown to increase product yield and/or productivity in many types of microbial cultivation. To test whether this cycling process could increase productivity during ethanol fermentations, we mimicked the process by manually cycling the fermentation for five cycles in shake flasks, and then compared the results to batch operation. Mimicking SCF for five cycles resulted in regular patterns with regards to glucose consumption, ethanol titer, pH, and biomass production. Compared to batch fermentation, our cycling strategy displayed improved ethanol volumetric productivity (the titer of ethanol produced in a given cycle per corresponding cycle time) and specific productivity (the amount of ethanol produced per cellular biomass) by 43.1 ± 11.6 and 42.7 ± 9.8%, respectively. Five successive cycles contributed to an improvement of overall productivity (the aggregate amount of ethanol produced at the end of a given cycle per total processing time) and the estimated annual ethanol productivity (the amount of ethanol produced per year) by 64.4 ± 3.3 and 33.1 ± 7.2%, respectively. This study provides proof of concept that applying SCF to ethanol production could significantly increase productivities, which will help strengthen the cellulosic ethanol industry.

Extractive Fermentation of Sugarcane Juice to Produce High Yield and Productivity of Bioethanol

NASA Astrophysics Data System (ADS)

Rofiqah, U.; Widjaja, T.; Altway, A.; Bramantyo, A.

2017-04-01

Ethanol production by batch fermentation requires a simple process and it is widely used. Batch fermentation produces ethanol with low yield and productivity due to the accumulation of ethanol in which poisons microorganisms in the fermenter. Extractive fermentation technique is applied to solve the microorganism inhibition problem by ethanol. Extractive fermentation technique can produce ethanol with high yield and productivity. In this process raffinate still, contains much sugar because conversion in the fermentation process is not perfect. Thus, to enhance ethanol yield and productivity, recycle system is applied by returning the raffinate from the extraction process to the fermentation process. This raffinate also contains ethanol which would inhibit the performance of microorganisms in producing ethanol during the fermentation process. Therefore, this study aims to find the optimum condition for the amount of solvent to broth ratio (S: B) and recycle to fresh feed ratio (R: F) which enter the fermenter to produce high yield and productivity. This research was carried out by experiment. In the experiment, sugarcane juice was fermented using Zymomonasmobilis mutant. The fermentation broth was extracted using amyl alcohol. The process was integrated with the recycle system by varying the recycle ratio. The highest yield and productivity is 22.3901% and 103.115 g / L.h respectively, obtained in a process that uses recycle to fresh feed ratio (R: F) of 50:50 and solvents to both ratio of 1.

Effect of bioaugmented inoculation on microbiota dynamics during solid-state fermentation of Daqu starter using autochthonous of Bacillus, Pediococcus, Wickerhamomyces and Saccharomycopsis.

PubMed

Li, Pan; Lin, Weifeng; Liu, Xiong; Wang, Xiaowen; Gan, Xing; Luo, Lixin; Lin, Wei-Tie

2017-02-01

Daqu, a traditional fermentation starter that is used for Chinese liquor and vinegar production, is still manufactured through a traditional spontaneous solid-state fermentation process with no selected microorganisms are intentionally inoculated. The aim of this work was to analyze the microbiota dynamics during the solid-state fermentation process of Daqu using a traditional and bioaugmented inoculation with autochthonous of Bacillus, Pediococcus, Saccharomycopsis and Wickerhamomyces at an industrial scale. Highly similar dynamics of physicochemical parameters, enzymatic activities and microbial communities were observed during the traditional and bioaugmented solid-state fermentation processes. Both in the two cases, groups of Streptophyta, Rickettsiales and Xanthomonadales only dominated the first two days, but Bacillales and Eurotiales became predominant members after 2 and 10 days fermentation, respectively. Phylotypes of Enterobacteriales, Lactobacillales, Saccharomycetales and Mucorales dominated the whole fermentation process. No significant difference (P > 0.05) in microbial structure was observed between the traditional and bioaugmented fermentation processes. However, slightly higher microbial richness was found during the bioaugmented fermentation process after 10 days fermentation. Our results reinforced the microbiota dynamic stability during the solid-state fermentation process of Daqu, and might aid in controlling the traditional Daqu manufacturing process. Copyright © 2016 Elsevier Ltd. All rights reserved.

Technical and economic assessment of processes for the production of butanol and acetone. Phase two: analysis of research advances. Energy Conversion and Utilization Technologies Program

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

None

1984-08-01

The initial objective of this work was to develop a methodology for analyzing the impact of technological advances as a tool to help establish priorities for R and D options in the field of biocatalysis. As an example of a biocatalyzed process, butanol/acetone fermentation (ABE process) was selected as the specific topic of study. A base case model characterizing the technology and economics associated with the ABE process was developed in the previous first phase of study. The project objectives were broadened in this second phase of work to provide parametric estimates of the economic and energy impacts of amore » variety of research advances in the hydrolysis, fermentation and purification sections of the process. The research advances analyzed in this study were based on a comprehensive literature review. The six process options analyzed were: continuous ABE fermentaton; vacuum ABE fermentation; Baelene solvent extraction; HRI's Lignol process; improved prehydrolysis/dual enzyme hydrolysis; and improved microorganism tolerance to butanol toxicity. Of the six options analyzed, only improved microorganism tolerance to butanol toxicity had a significant positive effect on energy efficiency and economics. This particular process option reduced the base case production cost (including 10% DCF return) by 20% and energy consumption by 16%. Figures and tables.« less

Lipolytic Changes in Fermented Sausages Produced with Turkey Meat: Effects of Starter Culture and Heat Treatment

PubMed Central

Kolsarici, Nuray; Candoğan, Kezban

2014-01-01

In this study, the effects of two different commercial starter culture mixes and processing methodologies (traditional and heat process) on the lipolytic changes of fermented sausages manufactured with turkey meat were evaluated during processing stages and storage. Free fatty acid (FFA) value increased with fermentation and during storage over 120 d in all fermented sausage groups produced with both processing methodologies (p<0.05). After drying stage, free fatty acid values of traditional style and heat processed fermented sausages were between 10.54-13.01% and 6.56-8.49%, respectively. Thiobarbituric acid (TBA) values of traditionally processed fermented sausages were between 0.220-0.450 mg·kg-1, and TBA values of heat processed fermented sausages were in a range of 0.405-0.795 mg·kg-1. Oleic and linoleic acids were predominant fatty acids in all fermented sausages. It was seen that fermented sausage groups produced with starter culture had lower TBA and FFA values in comparison with the control groups, and heat application inhibited the lipase enzyme activity and had an improving effect on lipid oxidation. As a result of these effects, heat processed fermented sausages had lower FFA and higher TBA values than the traditionally processed groups. PMID:26760744

Lipolytic Changes in Fermented Sausages Produced with Turkey Meat: Effects of Starter Culture and Heat Treatment.

PubMed

Karsloğlu, Betül; Çiçek, Ümran Ensoy; Kolsarici, Nuray; Candoğan, Kezban

2014-01-01

In this study, the effects of two different commercial starter culture mixes and processing methodologies (traditional and heat process) on the lipolytic changes of fermented sausages manufactured with turkey meat were evaluated during processing stages and storage. Free fatty acid (FFA) value increased with fermentation and during storage over 120 d in all fermented sausage groups produced with both processing methodologies (p<0.05). After drying stage, free fatty acid values of traditional style and heat processed fermented sausages were between 10.54-13.01% and 6.56-8.49%, respectively. Thiobarbituric acid (TBA) values of traditionally processed fermented sausages were between 0.220-0.450 mg·kg(-1), and TBA values of heat processed fermented sausages were in a range of 0.405-0.795 mg·kg(-1). Oleic and linoleic acids were predominant fatty acids in all fermented sausages. It was seen that fermented sausage groups produced with starter culture had lower TBA and FFA values in comparison with the control groups, and heat application inhibited the lipase enzyme activity and had an improving effect on lipid oxidation. As a result of these effects, heat processed fermented sausages had lower FFA and higher TBA values than the traditionally processed groups.

Phages of lactic acid bacteria: The role of genetics in understanding phage-host interactions and their co-evolutionary processes

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

Mahony, Jennifer, E-mail: j.mahony@ucc.ie; Ainsworth, Stuart; Stockdale, Stephen

Dairy fermentations are among the oldest food processing applications, aimed at preservation and shelf-life extension through the use of lactic acid bacteria (LAB) starter cultures, in particular strains of Lactococcus lactis, Streptococcus thermophilus, Lactobacillus spp. and Leuconostoc spp. Traditionally this was performed by continuous passaging of undefined cultures from a finished fermentation to initiate the next fermentation. More recently, consumer demands on consistent and desired flavours and textures of dairy products have led to a more defined approach to such processes. Dairy (starter) companies have responded to the need to define the nature and complexity of the starter culture mixes,more » and dairy fermentations are now frequently based on defined starter cultures of low complexity, where each starter component imparts specific technological properties that are desirable to the product. Both mixed and defined starter culture approaches create the perfect environment for the proliferation of (bacterio)phages capable of infecting these LAB. The repeated use of the same starter cultures in a single plant, coupled to the drive towards higher and consistent production levels, increases the risk and negative impact of phage infection. In this review we will discuss recent advances in tracking the adaptation of phages to the dairy industry, the advances in understanding LAB phage-host interactions, including evolutionary and genomic aspects.« less

Mechanisms for Nitrogen Oxide Formation during Ensiling of Dairy Feeds

EPA Science Inventory

Silage (ensiled feed), as a dairy’s greatest operational cost, is its most critical feed commodity. Ensiling is the process of converting entire harvested feed plants such as corn, sorghum, or alfalfa into fermented, stable anaerobic animal feed (i.e., silage). The continued use...

Mechanisms for Formation of Oxides of Nitrogen during Ensiling of Dairy Feeds

EPA Science Inventory

Silage (ensiled feed), as a dairy’s greatest operational cost, is its most critical feed commodity. Ensiling is the process of converting entire harvested feedplants such as corn, sorghum, or alfalfa into fermented, stable anaerobic animal feed (i.e., silage). The continued...

Relationship between fermentation index and other biochemical changes evaluated during the fermentation of Mexican cocoa (Theobroma cacao) beans.

PubMed

Romero-Cortes, Teresa; Salgado-Cervantes, Marco Antonio; García-Alamilla, Pedro; García-Alvarado, Miguel Angel; Rodríguez-Jimenes, Guadalupe del C; Hidalgo-Morales, Madeleine; Robles-Olvera, Víctor

2013-08-15

During traditional cocoa processing, the end of fermentation is empirically determined by the workers; consequently, a high variability on the quality of fermented cocoa beans is observed. Some physicochemical properties (such as fermentation index) have been used to measure the degree of fermentation and changes in quality, but only after the fermentation process has concluded, using dried cocoa beans. This would suggest that it is necessary to establish a relationship between the chemical changes inside the cocoa bean and the fermentation conditions during the fermentation in order to standardize the process. Cocoa beans were traditionally fermented inside wooden boxes, sampled every 24 h and analyzed to evaluate fermentation changes in complete bean, cotyledon and dried beans. The value of the fermentation index suggested as the minimal adequate (≥1) was observed at 72 h in all bean parts analyzed. At this time, values of pH, spectral absorption, total protein hydrolysis and vicilin-class globulins of fermented beans suggested that they were well fermented. Since no difference was found between the types of samples, the pH value could be used as a first indicator of the end of the fermentation and confirmed by evaluation of the fermentation index using undried samples, during the process. © 2013 Society of Chemical Industry.

Effect of low pH start-up on continuous mixed-culture lactic acid fermentation of dairy effluent.

PubMed

Choi, Gyucheol; Kim, Jaai; Lee, Changsoo

2016-12-01

Mixed-culture fermentation that does not require an energy-intensive sterilization process is a viable approach for the economically feasible production of lactic acid (LA) due to the potential use of organic waste as feedstock. This study investigated mixed-culture LA fermentation of whey, a high-strength organic wastewater, in continuous mode. Variations in the hydraulic retention time (HRT) from 120 to 8 h under different pH regimes in two thermophilic reactors (55 °C) were compared for their fermentation performance. One reactor was maintained at a low pH (pH 3.0) during operation at HRTs of 120 to 24 h and then adjusted to pH 5.5 in the later phases of fermentation at HRTs of 24 to 8 h (R1), while the second reactor was maintained at pH 5.5 throughout the experiment (R2). Although the LA production in R1 was negligible at low pH, it increased dramatically after the pH was raised to 5.5 and exceeded that in R2 when stabilized at HRTs of 8 and 12 h. The maximum yield (0.62 g LA/g substrate fed as the chemical oxygen demand (COD) equivalent), the production rate (11.5 g/L day), and the selectivity (95 %) of LA were all determined at a 12-h HRT in R1. Additionally, molecular and statistical analyses revealed that changes in the HRT and the pH significantly affected the bacterial community structure and thus the fermentation characteristics of the experimental reactors. Bacillus coagulans was likely the predominant LA producer in both reactors. The overall results suggest that low pH start-up has a positive effect on yield and selectivity in mixed-culture LA fermentation.

Bioprocess Intensification of Beer Fermentation Using Immobilised Cells

NASA Astrophysics Data System (ADS)

Verbelen, Pieter J.; Nedović, Viktor A.; Manojlović, Verica; Delvaux, Freddy R.; Laskošek-Čukalović, Ida; Bugarski, Branko; Willaert, Ronnie

Beer production with immobilised yeast has been the subject of research for approximately 30 years but has so far found limited application in the brewing industry, due to engineering problems, unrealised cost advantages, microbial contaminations and an unbalanced beer flavor (Linko et al. 1998; Brányik et al. 2005; Willaert and Nedović 2006). The ultimate aim of this research is the production of beer of desired quality within 1-3 days. Traditional beer fermentation systems use freely suspended yeast cells to ferment wort in an unstirred batch reactor. The primary fermentation takes approximately 7 days with a subsequent secondary fermentation (maturation) of several weeks. A batch culture system employing immobilization could benefit from an increased rate of fermentation. However, it appears that in terms of increasing productivity, a continuous fermentation system with immobilization would be the best method (Verbelen et al. 2006). An important issue of the research area is whether beer can be produced by immobilised yeast in continuous culture with the same characteristic as the traditional method.

Anaerobic Membrane Bioreactor for Continuous Lactic Acid Fermentation

PubMed Central

Fan, Rong; Ebrahimi, Mehrdad; Czermak, Peter

2017-01-01

Membrane bioreactor systems can enhance anaerobic lactic acid fermentation by reducing product inhibition, thus increasing productivity. In batch fermentations, the bioconversion of glucose is strongly inhibited in the presence of more than 100 g·L−1 lactic acid and is only possible when the product is simultaneously removed, which can be achieved by ceramic membrane filtration. The crossflow velocity is a more important determinant of flux than the transmembrane pressure. Therefore, to stabilize the performance of the membrane bioreactor system during continuous fermentation, the crossflow velocity was controlled by varying the biomass concentration, which was monitored in real-time using an optical sensor. Continuous fermentation under these conditions, thus, achieved a stable productivity of ~8 g·L−1·h−1 and the concentration of lactic acid was maintained at ~40 g·L−1 at a dilution rate of 0.2 h−1. No residual sugar was detected in the steady state with a feed concentration of 50 g·L−1. PMID:28467384

40 CFR Table 4 to Subpart Cccc of... - Continuous Compliance With Emission Limitations

Code of Federal Regulations, 2010 CFR

2010-07-01

... yeast in a fermentation stage (last (Trade), second-to-last (First Generation), or third-to-last (Stock... the applicable maximum concentration. 2. Each fed-batch fermenter producing yeast in a fermentation...

Ethanol Production from Traditional and Emerging Raw Materials

NASA Astrophysics Data System (ADS)

Rudolf, Andreas; Karhumaa, Kaisa; Hahn-Hägerdal, Bärbel

The ethanol industry of today utilizes raw materials rich in saccharides, such as sugar cane or sugar beets, and raw materials rich in starch, such as corn and wheat. The concern about supply of liquid transportation fuels, which has brought the crude oil price above 100 /barrel during 2006, together with the concern about global warming, have turned the interest towards large-scale ethanol production from lignocellulosic materials, such as agriculture and forestry residues. Baker's yeast Saccharomyces cerevisiae is the preferred fermenting microorganism for ethanol production because of its superior and well-documented industrial performance. Extensive work has been made to genetically improve S. cerevisiae to enable fermentation of lignocellulosic raw materials. Ethanolic fermentation processes are conducted in batch, fed-batch, or continuous mode, with or without cell recycling, the relative merit of which will be discussed.

Process design and optimization of novel wheat-based continuous bioethanol production system.

PubMed

Arifeen, Najmul; Wang, Ruohang; Kookos, Ioannis K; Webb, Colin; Koutinas, Apostolis A

2007-01-01

A novel design of a wheat-based biorefinery for bioethanol production, including wheat milling, gluten extraction as byproduct, fungal submerged fermentation for enzyme production, starch hydrolysis, fungal biomass autolysis for nutrient regeneration, yeast fermentation with recycling integrated with a pervaporation membrane for ethanol concentration, and fuel-grade ethanol purification by pressure swing distillation (PSD), was optimized in continuous mode using the equation-based software General Algebraic Modelling System (GAMS). The novel wheat biorefining strategy could result in a production cost within the range of dollars 0.96-0.50 gal(-1) ethanol (dollars 0.25-0.13 L(-1) ethanol) when the production capacity of the plant is within the range of 10-33.5 million gal y(-1) (37.85-126.8 million L y(-1)). The production of value-added byproducts (e.g., bran-rich pearlings, gluten, pure yeast cells) was identified as a crucial factor for improving the economics of fuel ethanol production from wheat. Integration of yeast fermentation with pervaporation membrane could result in the concentration of ethanol in the fermentation outlet stream (up to 40 mol %). The application of a PSD system that consisted of a low-pressure and a high-pressure column and employing heat integration between the high- and low-pressure columns resulted in reduced operating cost (up to 44%) for fuel-grade ethanol production.

Microbial production of a biofuel (acetone-butanol-ethanol) in a continuous bioreactor: impact of bleed and simultaneous product removal

USDA-ARS?s Scientific Manuscript database

Acetone butanol ethanol (ABE) was produced in an integrated continuous fermentation and product recovery system using a microbial strain Clostridium beijerinckii BA101 for ABE production and fermentation gases (CO2 and H2) for product removal by gas stripping. This represents a continuation of our ...

Study on fermentation kinetics and extraction process of rhamnolipid production by papermaking wastewater

NASA Astrophysics Data System (ADS)

Yu, Keer

2018-01-01

Paper mill wastewater (PMW) is the outlet water generated during pulp and papermaking process in the paper industry. Fermentation by wastewater can lower the cost of production as well as alleviate the pressure of wastewater treatment. Rhamnolipids find broad placations as natural surfactants. This paper studied the rhamnolipids fermentation by employing Pseudomonas aeruginosa isolated by the laboratory, and determined to use wastewater which filtered by medium speed filter paper and strain Z2, the culture conditions were optimized, based on the flask shaking fermentation. On the basis of 5L tank fermentation, batch fermentation was carried out, the yield of fermentation reached 7.067g/L and the fermentation kinetics model of cell growth, product formation and substrate consumption was established by using origin software, and the fermentation process could be simulated well. And studied on the extraction process of rhamnolipids, through fermentation dynamic equation analysis can predict the in fill material yield can be further improved. Research on the extraction process of rhamnolipid simplifies the operation of extraction, and lays the foundation for the industrial extraction.

Generalised additive modelling approach to the fermentation process of glutamate.

PubMed

Liu, Chun-Bo; Li, Yun; Pan, Feng; Shi, Zhong-Ping

2011-03-01

In this work, generalised additive models (GAMs) were used for the first time to model the fermentation of glutamate (Glu). It was found that three fermentation parameters fermentation time (T), dissolved oxygen (DO) and oxygen uptake rate (OUR) could capture 97% variance of the production of Glu during the fermentation process through a GAM model calibrated using online data from 15 fermentation experiments. This model was applied to investigate the individual and combined effects of T, DO and OUR on the production of Glu. The conditions to optimize the fermentation process were proposed based on the simulation study from this model. Results suggested that the production of Glu can reach a high level by controlling concentration levels of DO and OUR to the proposed optimization conditions during the fermentation process. The GAM approach therefore provides an alternative way to model and optimize the fermentation process of Glu. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

Recent trends in bioethanol production from food processing byproducts.

PubMed

Akbas, Meltem Yesilcimen; Stark, Benjamin C

2016-11-01

The widespread use of corn starch and sugarcane as sources of sugar for the production of ethanol via fermentation may negatively impact the use of farmland for production of food. Thus, alternative sources of fermentable sugars, particularly from lignocellulosic sources, have been extensively investigated. Another source of fermentable sugars with substantial potential for ethanol production is the waste from the food growing and processing industry. Reviewed here is the use of waste from potato processing, molasses from processing of sugar beets into sugar, whey from cheese production, byproducts of rice and coffee bean processing, and other food processing wastes as sugar sources for fermentation to ethanol. Specific topics discussed include the organisms used for fermentation, strategies, such as co-culturing and cell immobilization, used to improve the fermentation process, and the use of genetic engineering to improve the performance of ethanol producing fermenters.

REDUCING WASTEWATER FROM CUCUMBER PICKLING PROCESS BY CONTROLLED CULTURE FERMENTATION

EPA Science Inventory

On a demonstration scale, the controlled culture fermentation process (CCF) developed by the U.S. Food Fermentation Laboratory was compared with the conventional natural fermentation process (NF) in regard to product quality and yield and volume and concentration of wastewaters. ...

Microbial production of mannitol by Lactobacillus brevis 3-A5 from concentrated extract of Jerusalem artichoke tubers.

PubMed

Cao, Hailong; Yue, Min; Liu, Gang; Du, Yuguang; Yin, Heng

2018-05-01

In the present study, the conversion of the extract of Jerusalem artichoke tubers for mannitol production by Lactobacillus brevis 3-A5 was investigated. When the bacterium utilized enzymatic hydrolysates of Jerusalem artichoke extract as the main substrates in batch fermentation, the significant decrease in mannitol productivity was observed when the initial concentration of reducing sugar increased. Then, a strategy of continuous fed-batch fermentation was adopted for improving mannitol production with enzymatic hydrolysates of Jerusalem artichoke extract as main substrates. Although the concentration of mannitol could reach 199.86 g/L at the end of the fermentation, the productivity for the overall process of the fermentation was only 1.67 g/L/H. To improve the mannitol productivity with both higher yield and concentration, the simultaneous enzymatic saccharification and fermentation (SSF) was studied. In SSF, the mannitol production reached 176.50 g/L in 28 H with a productivity of 6.30 g/L/H and a yield of 0.68 g/g total sugar. Our study provides a cost-effective and eco-friendly method for mannitol production from a cheap biomass. © 2017 International Union of Biochemistry and Molecular Biology, Inc.

Noteworthy Facts about a Methane-Producing Microbial Community Processing Acidic Effluent from Sugar Beet Molasses Fermentation.

PubMed

Chojnacka, Aleksandra; Szczęsny, Paweł; Błaszczyk, Mieczysław K; Zielenkiewicz, Urszula; Detman, Anna; Salamon, Agnieszka; Sikora, Anna

2015-01-01

Anaerobic digestion is a complex process involving hydrolysis, acidogenesis, acetogenesis and methanogenesis. The separation of the hydrogen-yielding (dark fermentation) and methane-yielding steps under controlled conditions permits the production of hydrogen and methane from biomass. The characterization of microbial communities developed in bioreactors is crucial for the understanding and optimization of fermentation processes. Previously we developed an effective system for hydrogen production based on long-term continuous microbial cultures grown on sugar beet molasses. Here, the acidic effluent from molasses fermentation was used as the substrate for methanogenesis in an upflow anaerobic sludge blanket bioreactor. This study focused on the molecular analysis of the methane-yielding community processing the non-gaseous products of molasses fermentation. The substrate for methanogenesis produces conditions that favor the hydrogenotrophic pathway of methane synthesis. Methane production results from syntrophic metabolism whose key process is hydrogen transfer between bacteria and methanogenic Archaea. High-throughput 454 pyrosequencing of total DNA isolated from the methanogenic microbial community and bioinformatic sequence analysis revealed that the domain Bacteria was dominated by Firmicutes (mainly Clostridia), Bacteroidetes, δ- and γ-Proteobacteria, Cloacimonetes and Spirochaetes. In the domain Archaea, the order Methanomicrobiales was predominant, with Methanoculleus as the most abundant genus. The second and third most abundant members of the Archaeal community were representatives of the Methanomassiliicoccales and the Methanosarcinales. Analysis of the methanogenic sludge by scanning electron microscopy with Energy Dispersive X-ray Spectroscopy and X-ray diffraction showed that it was composed of small highly heterogeneous mineral-rich granules. Mineral components of methanogenic granules probably modulate syntrophic metabolism and methanogenic pathways. A rough functional analysis from shotgun data of the metagenome demonstrated that our knowledge of methanogenesis is poor and/or the enzymes responsible for methane production are highly effective, since despite reasonably good sequencing coverage, the details of the functional potential of the microbial community appeared to be incomplete.

Noteworthy Facts about a Methane-Producing Microbial Community Processing Acidic Effluent from Sugar Beet Molasses Fermentation

PubMed Central

Chojnacka, Aleksandra; Szczęsny, Paweł; Błaszczyk, Mieczysław K.; Zielenkiewicz, Urszula; Detman, Anna; Salamon, Agnieszka; Sikora, Anna

2015-01-01

Anaerobic digestion is a complex process involving hydrolysis, acidogenesis, acetogenesis and methanogenesis. The separation of the hydrogen-yielding (dark fermentation) and methane-yielding steps under controlled conditions permits the production of hydrogen and methane from biomass. The characterization of microbial communities developed in bioreactors is crucial for the understanding and optimization of fermentation processes. Previously we developed an effective system for hydrogen production based on long-term continuous microbial cultures grown on sugar beet molasses. Here, the acidic effluent from molasses fermentation was used as the substrate for methanogenesis in an upflow anaerobic sludge blanket bioreactor. This study focused on the molecular analysis of the methane-yielding community processing the non-gaseous products of molasses fermentation. The substrate for methanogenesis produces conditions that favor the hydrogenotrophic pathway of methane synthesis. Methane production results from syntrophic metabolism whose key process is hydrogen transfer between bacteria and methanogenic Archaea. High-throughput 454 pyrosequencing of total DNA isolated from the methanogenic microbial community and bioinformatic sequence analysis revealed that the domain Bacteria was dominated by Firmicutes (mainly Clostridia), Bacteroidetes, δ- and γ-Proteobacteria, Cloacimonetes and Spirochaetes. In the domain Archaea, the order Methanomicrobiales was predominant, with Methanoculleus as the most abundant genus. The second and third most abundant members of the Archaeal community were representatives of the Methanomassiliicoccales and the Methanosarcinales. Analysis of the methanogenic sludge by scanning electron microscopy with Energy Dispersive X-ray Spectroscopy and X-ray diffraction showed that it was composed of small highly heterogeneous mineral-rich granules. Mineral components of methanogenic granules probably modulate syntrophic metabolism and methanogenic pathways. A rough functional analysis from shotgun data of the metagenome demonstrated that our knowledge of methanogenesis is poor and/or the enzymes responsible for methane production are highly effective, since despite reasonably good sequencing coverage, the details of the functional potential of the microbial community appeared to be incomplete. PMID:26000448

Characteristics of an immobilized yeast cell system using very high gravity for the fermentation of ethanol.

PubMed

Ji, Hairui; Yu, Jianliang; Zhang, Xu; Tan, Tianwei

2012-09-01

The characteristics of ethanol production by immobilized yeast cells were investigated for both repeated batch fermentation and continuous fermentation. With an initial sugar concentration of 280 g/L during the repeated batch fermentation, more than 98% of total sugar was consumed in 65 h with an average ethanol concentration and ethanol yield of 130.12 g/L and 0.477 g ethanol/g consumed sugar, respectively. The immobilized yeast cell system was reliable for at least 10 batches and for a period of 28 days without accompanying the regeneration of Saccharomyces cerevisiae inside the carriers. The multistage continuous fermentation was carried out in a five-stage column bioreactor with a total working volume of 3.75 L. The bioreactor was operated for 26 days at a dilution rate of 0.015 h(-1). The ethanol concentration of the effluent reached 130.77 g/L ethanol while an average 8.18 g/L residual sugar remained. Due to the high osmotic pressure and toxic ethanol, considerable yeast cells died without regeneration, especially in the last two stages, which led to the breakdown of the whole system of multistage continuous fermentation.

Study on color identification for monitoring and controlling fermentation process of branched chain amino acid

NASA Astrophysics Data System (ADS)

Ma, Lei; Wang, Yizhong; Chen, Ning; Liu, Tiegen; Xu, Qingyang; Kong, Fanzhi

2008-12-01

In this paper, a new method for monitoring and controlling fermentation process of branched chain amino acid (BCAA) was proposed based on color identification. The color image of fermentation broth of BCAA was firstly taken by a CCD camera. Then, it was changed from RGB color model to HIS color model. Its histograms of hue H and saturation S were calculated, which were used as the input of a designed BP network. The output of the BP network was the description of the color of fermentation broth of BCAA. After training, the color of fermentation broth was identified by the BP network according to the histograms of H and S of a fermentation broth image. Along with other parameters, the fermentation process of BCAA was monitored and controlled to start the stationary phase of fermentation soon. Experiments were conducted with satisfied results to show the feasibility and usefulness of color identification of fermentation broth in fermentation process control of BCAA.

Enzymes in Fermented Fish.

PubMed

Giyatmi; Irianto, H E

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

Fermentation process for the production of organic acids

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

Hermann, Theron; Reinhardt, James; Yu, Xiaohui

This invention relates to improvements in the fermentation process used in the production of organic acids from biological feedstock using bacterial catalysts. The improvements in the fermentation process involve providing a fermentation medium comprising an appropriate form of inorganic carbon, an appropriate amount of aeration and a biocatalyst with an enhanced ability to uptake and assimilate the inorganic carbon into the organic acids. This invention also provides, as a part of an integrated fermentation facility, a novel process for producing a solid source of inorganic carbon by sequestering carbon released from the fermentation in an alkali solution.

Oxygen Response of the Wine Yeast Saccharomyces cerevisiae EC1118 Grown under Carbon-Sufficient, Nitrogen-Limited Enological Conditions

PubMed Central

Aceituno, Felipe F.; Orellana, Marcelo; Torres, Jorge; Mendoza, Sebastián; Slater, Alex W.; Melo, Francisco

2012-01-01

Discrete additions of oxygen play a critical role in alcoholic fermentation. However, few studies have quantitated the fate of dissolved oxygen and its impact on wine yeast cell physiology under enological conditions. We simulated the range of dissolved oxygen concentrations that occur after a pump-over during the winemaking process by sparging nitrogen-limited continuous cultures with oxygen-nitrogen gaseous mixtures. When the dissolved oxygen concentration increased from 1.2 to 2.7 μM, yeast cells changed from a fully fermentative to a mixed respirofermentative metabolism. This transition is characterized by a switch in the operation of the tricarboxylic acid cycle (TCA) and an activation of NADH shuttling from the cytosol to mitochondria. Nevertheless, fermentative ethanol production remained the major cytosolic NADH sink under all oxygen conditions, suggesting that the limitation of mitochondrial NADH reoxidation is the major cause of the Crabtree effect. This is reinforced by the induction of several key respiratory genes by oxygen, despite the high sugar concentration, indicating that oxygen overrides glucose repression. Genes associated with other processes, such as proline uptake, cell wall remodeling, and oxidative stress, were also significantly affected by oxygen. The results of this study indicate that respiration is responsible for a substantial part of the oxygen response in yeast cells during alcoholic fermentation. This information will facilitate the development of temporal oxygen addition strategies to optimize yeast performance in industrial fermentations. PMID:23001663

Oxygen response of the wine yeast Saccharomyces cerevisiae EC1118 grown under carbon-sufficient, nitrogen-limited enological conditions.

PubMed

Aceituno, Felipe F; Orellana, Marcelo; Torres, Jorge; Mendoza, Sebastián; Slater, Alex W; Melo, Francisco; Agosin, Eduardo

2012-12-01

Discrete additions of oxygen play a critical role in alcoholic fermentation. However, few studies have quantitated the fate of dissolved oxygen and its impact on wine yeast cell physiology under enological conditions. We simulated the range of dissolved oxygen concentrations that occur after a pump-over during the winemaking process by sparging nitrogen-limited continuous cultures with oxygen-nitrogen gaseous mixtures. When the dissolved oxygen concentration increased from 1.2 to 2.7 μM, yeast cells changed from a fully fermentative to a mixed respirofermentative metabolism. This transition is characterized by a switch in the operation of the tricarboxylic acid cycle (TCA) and an activation of NADH shuttling from the cytosol to mitochondria. Nevertheless, fermentative ethanol production remained the major cytosolic NADH sink under all oxygen conditions, suggesting that the limitation of mitochondrial NADH reoxidation is the major cause of the Crabtree effect. This is reinforced by the induction of several key respiratory genes by oxygen, despite the high sugar concentration, indicating that oxygen overrides glucose repression. Genes associated with other processes, such as proline uptake, cell wall remodeling, and oxidative stress, were also significantly affected by oxygen. The results of this study indicate that respiration is responsible for a substantial part of the oxygen response in yeast cells during alcoholic fermentation. This information will facilitate the development of temporal oxygen addition strategies to optimize yeast performance in industrial fermentations.

Moisture content during extrusion of oats impacts the initial fermentation metabolites and probiotic bacteria during extended fermentation by human fecal microbiota.

PubMed

Brahma, Sandrayee; Weier, Steven A; Rose, Devin J

2017-07-01

Extrusion exposes flour components to high pressure and shear during processing, which may affect the dietary fiber fermentability by human fecal microbiota. The objective of this study was to determine the effect of flour moisture content during extrusion on in vitro fermentation properties of whole grain oats. Extrudates were processed at three moisture levels (15%, 18%, and 21%) at fixed screw speed (300rpm) and temperature (130°C). The extrudates were then subjected to in vitro digestion and fermentation. Extrusion moisture significantly affected water-extractable β-glucan (WE-BG) in the extrudates, with samples processed at 15% moisture (lowest) and 21% moisture (highest) having the highest concentration of WE-BG. After the first 8h of fermentation, more WE-BG remained in fermentation media in samples processed at 15% moisture compared with the other conditions. Also, extrusion moisture significantly affected the production of acetate, butyrate, and total SCFA by the microbiota during the first 8h of fermentation. Microbiota grown on extrudates processed at 18% moisture had the highest production of acetate and total SCFA, whereas bacteria grown on extrudates processed at 15% and 18% moisture had the highest butyrate production. After 24h of fermentation, samples processed at 15% moisture supported lower Bifidobacterium counts than those produced at other conditions, but had among the highest Lactobacillus counts. Thus, moisture content during extrusion significantly affects production of fermentation metabolites by the gut microbiota during the initial stages of fermentation, while also affecting probiotic bacteria counts during extended fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reduction in environmental impact of sulfuric acid hydrolysis of bamboo for production of fuel ethanol.

PubMed

Sun, Zhao-Yong; Tang, Yue-Qin; Morimura, Shigeru; Kida, Kenji

2013-01-01

Fuel ethanol can be produced from bamboo by concentrated sulfuric acid hydrolysis followed by continuous ethanol fermentation. To reduce the environmental impact of this process, treatment of the stillage, reuse of the sulfuric acid and reduction of the process water used were studied. The total organic carbon (TOC) concentration of stillage decreased from 29,688 to 269 mg/l by thermophilic methane fermentation followed by aerobic treatment. Washing the solid residue from acid hydrolysis with effluent from the biological treatment increased the sugar recovery from 69.3% to 79.3%. Sulfuric acid recovered during the acid-sugar separation process was condensed and reused for hydrolysis, resulting in a sugar recovery efficiency of 76.8%, compared to 80.1% when fresh sulfuric acid was used. After acetate removal, the condensate could be reused as elution water in the acid-sugar separation process. As much as 86.3% of the process water and 77.6% of the sulfuric acid could be recycled. Copyright © 2012 Elsevier Ltd. All rights reserved.

Modified ADM1 for modeling free ammonia inhibition in anaerobic acidogenic fermentation with high-solid sludge.

PubMed

Bai, Jie; Liu, He; Yin, Bo; Ma, Huijun; Chen, Xinchun

2017-02-01

Anaerobic acidogenic fermentation with high-solid sludge is a promising method for volatile fatty acid (VFA) production to realize resource recovery. In this study, to model inhibition by free ammonia in high-solid sludge fermentation, the anaerobic digestion model No. 1 (ADM1) was modified to simulate the VFA generation in batch, semi-continuous and full scale sludge. The ADM1 was operated on the platform AQUASIM 2.0. Three kinds of inhibition forms, e.g., simple inhibition, Monod and non-inhibition forms, were integrated into the ADM1 and tested with the real experimental data for batch and semi-continuous fermentation, respectively. The improved particle swarm optimization technique was used for kinetic parameter estimation using the software MATLAB 7.0. In the modified ADM1, the K s of acetate is 0.025, the k m,ac is 12.51, and the K I_NH3 is 0.02, respectively. The results showed that the simple inhibition model could simulate the VFA generation accurately while the Monod model was the better inhibition kinetics form in semi-continuous fermentation at pH10.0. Finally, the modified ADM1 could successfully describe the VFA generation and ammonia accumulation in a 30m 3 full-scale sludge fermentation reactor, indicating that the developed model can be applicable in high-solid sludge anaerobic fermentation. Copyright © 2016. Published by Elsevier B.V.

Biomass Gasification Research and Development Project

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

Ahring, Birgitte K.

2014-07-22

The overall objective of the BioChemCat project was to demonstrate the feasibility of using Advanced Wet Oxidation Steam-Explosion (AWEx) process to open and solubilize lignocellulosic biomass (LBM) coupled to an innovative mixed culture fermentation technology capable of producing a wide range of volatile fatty acids (VFAs) from all sugars present in LBM. The VFAs will then be separated and converted to hydrocarbon biofuel through catalytic upgrading. By continuously removing VFAs as they are produced (extractive fermentation), we were able to recover the VFAs while both eliminating the need for pH adjustment and increasing the fermentation productivity. The recovered VFAs weremore » then esterified and upgraded to hydrocarbon fuels through a parallel series of hydrogenolysis/decarboxylation and dehydration reactions. We also demonstrated that a portion of the residual lignin fraction was solubilized and converted into VFAs, also improving the yields of VFAs. The remaining lignin fraction was then shown to be available (after dewatering and drying) for use as a lignin-enriched fuel pellet or as a feedstock for further processing.« less

Continuous energy recovery and nutrients removal from molasses wastewater by synergistic system of dark fermentation and algal culture under various fermentation types.

PubMed

Ren, Hong-Yu; Kong, Fanying; Ma, Jun; Zhao, Lei; Xie, Guo-Jun; Xing, Defeng; Guo, Wan-Qian; Liu, Bing-Feng; Ren, Nan-Qi

2018-03-01

Synergistic system of dark fermentation and algal culture was initially operated at batch mode to investigate the energy production and nutrients removal from molasses wastewater in butyrate-type, ethanol-type and propionate-type fermentations. Butyrate-type fermentation was the most appropriate fermentation type for the synergistic system and exhibited the accumulative hydrogen volume of 658.3 mL L -1 and hydrogen yield of 131.7 mL g -1 COD. By-products from dark fermentation (mainly acetate and butyrate) were further used to cultivate oleaginous microalgae. The maximum algal biomass and lipid content reached 1.01 g L -1 and 38.5%, respectively. In continuous operation, the synergistic system was stable and efficient, and energy production increased from 8.77 kJ L -1  d -1 (dark fermentation) to 17.3 kJ L -1  d -1 (synergistic system). Total COD, TN and TP removal efficiencies in the synergistic system reached 91.1%, 89.1% and 85.7%, respectively. This study shows the potential of the synergistic system in energy recovery and wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bioethanol production: an integrated process of low substrate loading hydrolysis-high sugars liquid fermentation and solid state fermentation of enzymatic hydrolysis residue.

PubMed

Chu, Qiulu; Li, Xin; Ma, Bin; Xu, Yong; Ouyang, Jia; Zhu, Junjun; Yu, Shiyuan; Yong, Qiang

2012-11-01

An integrated process of enzymatic hydrolysis and fermentation was investigated for high ethanol production. The combination of enzymatic hydrolysis at low substrate loading, liquid fermentation of high sugars concentration and solid state fermentation of enzymatic hydrolysis residue was beneficial for conversion of steam explosion pretreated corn stover to ethanol. The results suggested that low substrate loading hydrolysis caused a high enzymatic hydrolysis yield; the liquid fermentation of about 200g/L glucose by Saccharomyces cerevisiae provided a high ethanol concentration which could significantly decrease cost of the subsequent ethanol distillation. A solid state fermentation of enzymatic hydrolysis residue was combined, which was available to enhance ethanol production and cellulose-to-ethanol conversion. The results of solid state fermentation demonstrated that the solid state fermentation process accompanied by simultaneous saccharification and fermentation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Ethanol production from xylose with the yeast Pichia stipitis and simultaneous product recovery by gas stripping using a gas-lift loop fermentor with attached side-arm (GLSA).

PubMed

Domínguez, J M; Cao, N; Gong, C S; Tsao, G T

2000-02-05

The bioconversion of xylose into ethanol with the yeast Pichia stipitis CBS 5773 is inhibited when 20 g/L of ethanol are present in the fermentation broth. In order to avoid this limitation, the fermentation was carried out with simultaneous recovery of product by CO(2) stripping. The fermentation was also improved by attaching a side-arm to the main body of a classical gas-lift loop fermentor. This side-arm increases the liquid circulation, mass transfer, and gas distribution, reducing the amount of oxygen in the inlet gas necessary to perform the fermentation of xylose under microaerobic conditions (K(L)a approximately 16 h(-1)). The continuous stripping of ethanol from the fermentation broth in this new bioreactor system allowed the consumption of higher xylose concentrations than using Erlenmeyer shaker flasks, improved significantly the process productivity and provided a clean ethanol solution by using an ice-cooled condenser system. Finally, a fed-batch fermentation was carried out with a K(L)a = 15.8 h(-1). Starting with 248.2 g of xylose, 237.6 g of xylose was consumed to produce 88.1 g of ethanol which represents 72.6% of the theoretical yield (47.2 g/L of ethanol was recovered in the condenser, while 9.6 g/L remained in the fermentation broth). Copyright 2000 John Wiley & Sons, Inc.

High-strength fermentable wastewater reclamation through a sequential process of anaerobic fermentation followed by microalgae cultivation.

PubMed

Qi, Wenqiang; Chen, Taojing; Wang, Liang; Wu, Minghong; Zhao, Quanyu; Wei, Wei

2017-03-01

In this study, the sequential process of anaerobic fermentation followed by microalgae cultivation was evaluated from both nutrient and energy recovery standpoints. The effects of different fermentation type on the biogas generation, broth metabolites' composition, algal growth and nutrients' utilization, and energy conversion efficiencies for the whole processes were discussed. When the fermentation was designed to produce hydrogen-dominating biogas, the total energy conversion efficiency (TECE) of the sequential process was higher than that of the methane fermentation one. With the production of hydrogen in anaerobic fermentation, more organic carbon metabolites were left in the broth to support better algal growth with more efficient incorporation of ammonia nitrogen. By applying the sequential process, the heat value conversion efficiency (HVCE) for the wastewater could reach 41.2%, if methane was avoided in the fermentation biogas. The removal efficiencies of organic metabolites and NH 4 + -N in the better case were 100% and 98.3%, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mathematical modeling of a continuous alcoholic fermentation process in a two-stage tower reactor cascade with flocculating yeast recycle.

PubMed

de Oliveira, Samuel Conceição; de Castro, Heizir Ferreira; Visconti, Alexandre Eliseu Stourdze; Giudici, Reinaldo

2015-03-01

Experiments of continuous alcoholic fermentation of sugarcane juice with flocculating yeast recycle were conducted in a system of two 0.22-L tower bioreactors in series, operated at a range of dilution rates (D 1 = D 2 = 0.27-0.95 h(-1)), constant recycle ratio (α = F R /F = 4.0) and a sugar concentration in the feed stream (S 0) around 150 g/L. The data obtained in these experimental conditions were used to adjust the parameters of a mathematical model previously developed for the single-stage process. This model considers each of the tower bioreactors as a perfectly mixed continuous reactor and the kinetics of cell growth and product formation takes into account the limitation by substrate and the inhibition by ethanol and biomass, as well as the substrate consumption for cellular maintenance. The model predictions agreed satisfactorily with the measurements taken in both stages of the cascade. The major differences with respect to the kinetic parameters previously estimated for a single-stage system were observed for the maximum specific growth rate, for the inhibition constants of cell growth and for the specific rate of substrate consumption for cell maintenance. Mathematical models were validated and used to simulate alternative operating conditions as well as to analyze the performance of the two-stage process against that of the single-stage process.

Lactic acid and methane: improved exploitation of biowaste potential.

PubMed

Dreschke, G; Probst, M; Walter, A; Pümpel, T; Walde, J; Insam, H

2015-01-01

This feasibility study investigated a two-step biorefining approach to increase the value gained by recycling of organic municipal solid waste. Firstly, lactic acid was produced via batch fermentation at 37°C using the indigenous microbiome. Experiments revealed an optimal fermentation period of 24h resulting in high yields of lactic acid (up to 37gkg(-1)). The lactic acid proportion of total volatile fatty acid content reached up to 83%. Lactobacilli were selectively enriched to up to 75% of the bacterial community. Additionally conversion of organic matter to lactic acid was increased from 22% to 30% through counteracting end product inhibition by continuous lactic acid extraction. Secondly, fermentation residues were used as co-substrate in biomethane production yielding up to 618±41Nmlbiomethaneg(-1) volatile solids. Digestate, the only end product of this process can be used as organic fertilizer. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rapid production of organic fertilizer by dynamic high-temperature aerobic fermentation (DHAF) of food waste.

PubMed

Jiang, Yang; Ju, Meiting; Li, Weizun; Ren, Qingbin; Liu, Le; Chen, Yu; Yang, Qian; Hou, Qidong; Liu, Yiliang

2015-12-01

Keep composting matrix in continuous collision and friction under a relatively high-temperature can significantly accelerate the progress of composting. A bioreactor was designed according to the novel process. Using this technology, organic fertilizer could be produced within 96h. The electric conductivity (EC) and pH value reached to a stable value of 2.35mS/cm and 7.7 after 96h of fermentation. The total carbon/total nitrogen (TC/TN) and dissolved carbon/dissolved nitrogen (DC/DN) ratio was decrease from 27.3 and 36.2 to 17.4 and 7.6 respectively. In contrast, it needed 24days to achieve the similar result in traditional static composting (TSC). Compost particles with different size were analyzed to explore the rapid degradation mechanism of food waste. The evidence of anaerobic fermentation was firstly discovered in aerobic composting. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of microaerobic fermentation in preprocessing fibrous lignocellulosic materials.

PubMed

Alattar, Manar Arica; Green, Terrence R; Henry, Jordan; Gulca, Vitalie; Tizazu, Mikias; Bergstrom, Robby; Popa, Radu

2012-06-01

Amending soil with organic matter is common in agricultural and logging practices. Such amendments have benefits to soil fertility and crop yields. These benefits may be increased if material is preprocessed before introduction into soil. We analyzed the efficiency of microaerobic fermentation (MF), also referred to as Bokashi, in preprocessing fibrous lignocellulosic (FLC) organic materials using varying produce amendments and leachate treatments. Adding produce amendments increased leachate production and fermentation rates and decreased the biological oxygen demand of the leachate. Continuously draining leachate without returning it to the fermentors led to acidification and decreased concentrations of polysaccharides (PS) in leachates. PS fragmentation and the production of soluble metabolites and gases stabilized in fermentors in about 2-4 weeks. About 2 % of the carbon content was lost as CO(2). PS degradation rates, upon introduction of processed materials into soil, were similar to unfermented FLC. Our results indicate that MF is insufficient for adequate preprocessing of FLC material.

Highly efficient production of optically pure l-lactic acid from corn stover hydrolysate by thermophilic Bacillus coagulans.

PubMed

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.

Bio-hydrogen production from molasses by anaerobic fermentation in continuous stirred tank reactor

NASA Astrophysics Data System (ADS)

Han, Wei; Li, Yong-feng; Chen, Hong; Deng, Jie-xuan; Yang, Chuan-ping

2010-11-01

A study of bio-hydrogen production was performed in a continuous flow anaerobic fermentation reactor (with an available volume of 5.4 L). The continuous stirred tank reactor (CSTR) for bio-hydrogen production was operated under the organic loading rates (OLR) of 8-32 kg COD/m3 reactor/d (COD: chemical oxygen demand) with molasses as the substrate. The maximum hydrogen production yield of 8.19 L/d was obtained in the reactor with the OLR increased from 8 kg COD/m3 reactor/d to 24 kg COD/m3 d. However, the hydrogen production and volatile fatty acids (VFAs) drastically decreased at an OLR of 32 kg COD/m3 reactor/d. Ethanoi, acetic, butyric and propionic were the main liquid fermentation products with the percentages of 31%, 24%, 20% and 18%, which formed the mixed-type fermentation.

Effects of fermented milk treatment on microbial population and metabolomic outcomes in a three-stage semi-continuous culture system.

PubMed

Cha, Kwang Hyun; Lee, Eun Ha; Yoon, Hyo Shin; Lee, Jae Ho; Kim, Joo Yun; Kang, Kyungsu; Park, Jin-Soo; Jin, Jong Beom; Ko, GwangPyo; Pan, Cheol-Ho

2018-10-15

We investigated the impact of a fermented milk product on gut microbiota and their metabolism in 3 different conditions of the colon with a systemic viewpoint. An in vitro semi-continuous anaerobic cultivation was used to assess the colon compartment-specific influence of fermented milk, followed by a multiomics approach combining 16S rDNA amplicon sequencing and nuclear magnetic resonance (NMR) spectroscopy. The microbiome profiling and metabolomic features were significantly different across three colon compartments and after fermented milk treatment. Integrative correlation analysis indicated that the alteration of butyrate-producing microbiota (Veillonella, Roseburia, Lachnospira, and Coprococcus) and some primary metabolites (butyrate, ethanol, lactate, and isobutyrate) in the treatment group had a strong association with the fermented milk microorganisms. Our findings suggested that fermented milk treatment significantly affected microbial population in an in vitro cultivation system as well as the colonic metabolome in different ways in each of colon compartment. Copyright © 2018. Published by Elsevier Ltd.

Enteric methane production and ruminal fermentation from forage brassica diets fed in continuous culture

USDA-ARS?s Scientific Manuscript database

Brassicas provide forage for livestock during the late fall when traditional perennial cool-season forages are not productive. However, little research exists on ruminal fermentation and methane(CH4) production of brassicas fed as forage. A continuous culture fermentor system was used to assess nutr...

Effect of substrate concentration on hydrogen production by photo-fermentation in the pilot-scale baffled bioreactor.

PubMed

Lu, Chaoyang; Zhang, Zhiping; Zhou, Xuehua; Hu, Jianjun; Ge, Xumeng; Xia, Chenxi; Zhao, Jia; Wang, Yi; Jing, Yanyan; Li, Yameng; Zhang, Quanguo

2018-01-01

Effect of substrate concentration on photo-fermentative hydrogen production was studied with a self-designed 4m 3 pilot-scale baffled photo-fermentative hydrogen production reactor (BPHR). The relationships between parameters, such as hydrogen production rate (HPR, mol H 2 /m 3 /d), hydrogen concentration, pH value, oxidation-reduction potential, biomass concentration (volatile suspended solids, VSS) and reducing sugar concentration, during the photo-fermentative hydrogen production process were investigated. The highest HPR of 202.64±8.83mol/m 3 /d was achieved in chamber #3 at a substrate concentration of 20g/L. Hydrogen contents were in the range of 42.19±0.94%-49.71±0.27%. HPR increased when organic loading rate was increased from 3.3 to 20g/L/d, then decreased when organic loading rate was further increased to 25g/L/d. A maximum HPR of 148.65±4.19mol/m 3 /d was obtained when organic loading rate was maintained at 20g/L/d during continuous bio-hydrogen production. Copyright © 2017 Elsevier Ltd. All rights reserved.

75 FR 16388 - Approval and Promulgation of Implementation Plans; Commonwealth of Kentucky: Prevention of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-01

... ``chemical process plants'' that produce ethanol through a natural fermentation process (hereafter referred... for excluding ``chemical process plants'' that produce ethanol through a natural fermentation process... facilities that produce ethanol by natural fermentation processes. Kentucky's February 5, 2010, SIP...

Fermentation of philippine vegetable blends.

PubMed

Orillo, C A; Sison, E C; Luis, M; Pederson, C S

1969-01-01

Seven blends of Philipphine vegetables, two of which contained soybeans and one mongo bean sprouts, were prepared for fermentation and study of microbiological and chemical changes. The fermentations were typical lactic acid bacterial fermentations, initiated by Leuconostoc mesenteroides and continued by Lactobacillus brevis, Pediococcus cerevisiae, and L. plantarum. The combination of high acidity and low pH resembled other vegetable fermentations, such as sauerkraut. The procedure offers a method of preserving surplus vegetables, and, in addition, a method for incorporating and preserving the high-protein-containing soybeans.

A thermochemical-biochemical hybrid processing of lignocellulosic biomass for producing fuels and chemicals.

PubMed

Shen, Yanwen; Jarboe, Laura; Brown, Robert; Wen, Zhiyou

2015-12-01

Thermochemical-biological hybrid processing uses thermochemical decomposition of lignocellulosic biomass to produce a variety of intermediate compounds that can be converted into fuels and chemicals through microbial fermentation. It represents a unique opportunity for biomass conversion as it mitigates some of the deficiencies of conventional biochemical (pretreatment-hydrolysis-fermentation) and thermochemical (pyrolysis or gasification) processing. Thermochemical-biological hybrid processing includes two pathways: (i) pyrolysis/pyrolytic substrate fermentation, and (ii) gasification/syngas fermentation. This paper provides a comprehensive review of these two hybrid processing pathways, including the characteristics of fermentative substrates produced in the thermochemical stage and microbial utilization of these compounds in the fermentation stage. The current challenges of these two biomass conversion pathways include toxicity of the crude pyrolytic substrates, the inhibition of raw syngas contaminants, and the mass-transfer limitations in syngas fermentation. Possible approaches for mitigating substrate toxicities are discussed. The review also provides a summary of the current efforts to commercialize hybrid processing. Copyright © 2015 Elsevier Inc. All rights reserved.

Changes in the ginsenoside content during the fermentation process using microbial strains.

PubMed

Lee, So Jin; Kim, Yunjeong; Kim, Min-Gul

2015-10-01

Red ginseng (RG) is processed from Panax ginseng via several methods including heat treatment, mild acid hydrolysis, and microbial conversion to transform the major ginsenosides into minor ginsenosides, which have greater pharmaceutical activities. During the fermentation process using microbial strains in a machine for making red ginseng, a change of composition occurs after heating. Therefore, we confirmed that fermentation had occurred using only microbial strains and evaluated the changes in the ginsenosides and their chemical composition. To confirm the fermentation by microbial strains, the fermented red ginseng was made with microbial strains (w-FRG) or without microbial strains (n-FRG), and the fermentation process was performed to tertiary fermentation. The changes in the ginsenoside composition of the self-manufactured FRG using the machine were evaluated using HPLC, and the 20 ginsenosides were analyzed. Additionally, we investigated changes of the reducing sugar and polyphenol contents during fermentation process. In the fermentation process, ginsenosides Re, Rg1, and Rb1 decreased but ginsenosides Rh1, F2, Rg3, and Compound Y (C.Y) increased in primary FRG more than in the raw ginseng and RG. The content of phenolic compounds was high in FRG and the highest in the tertiary w-FRG. Moreover, the reducing sugar content was approximately three times higher in the tertiary w-FRG than in the other n-FRG. As the results indicate, we confirmed the changes in the ginsenoside content and the role of microbial strains in the fermentation process.

An economic comparison of different fermentation configurations to convert corn stover to ethanol using Z. mobilis and Saccharomyces.

PubMed

Dutta, Abhijit; Dowe, Nancy; Ibsen, Kelly N; Schell, Daniel J; Aden, Andy

2010-01-01

Numerous routes are being explored to lower the cost of cellulosic ethanol production and enable large-scale production. One critical area is the development of robust cofermentative organisms to convert the multiple, mixed sugars found in biomass feedstocks to ethanol at high yields and titers without the need for processing to remove inhibitors. Until such microorganisms are commercialized, the challenge is to design processes that exploit the current microorganisms' strengths. This study explored various process configurations tailored to take advantage of the specific capabilities of three microorganisms, Z. mobilis 8b, S. cerevisiae, and S. pastorianus. A technoeconomic study, based on bench-scale experimental data generated by integrated process testing, was completed to understand the resulting costs of the different process configurations. The configurations included whole slurry fermentation with a coculture, and separate cellulose simultaneous saccharification and fermentation (SSF) and xylose fermentations with none, some or all of the water to the SSF replaced with the fermented liquor from the xylose fermentation. The difference between the highest and lowest ethanol cost for the different experimental process configurations studied was $0.27 per gallon ethanol. Separate fermentation of solid and liquor streams with recycle of fermented liquor to dilute the solids gave the lowest ethanol cost, primarily because this option achieved the highest concentrations of ethanol after fermentation. Further studies, using methods similar to ones employed here, can help understand and improve the performance and hence the economics of integrated processes involving enzymes and fermentative microorganisms.

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

PubMed Central

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

2017-01-01

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

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

PubMed

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

2017-01-01

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

Influence of Fermentation Process on the Anthocyanin Composition of Wine and Vinegar Elaborated from Strawberry.

PubMed

Hornedo-Ortega, Ruth; Álvarez-Fernández, M Antonia; Cerezo, Ana B; Garcia-Garcia, Isidoro; Troncoso, Ana M; Garcia-Parrilla, M Carmen

2017-02-01

Anthocyanins are the major polyphenolic compounds in strawberry fruit responsible for its color. Due to their sensitivity, they are affected by food processing techniques such as fermentation that alters both their chemical composition and organoleptic properties. This work aims to evaluate the impact of different fermentation processes on individual anthocyanins compounds in strawberry wine and vinegar by UHPLC-MS/MS Q Exactive analysis. Nineteen, 18, and 14 anthocyanin compounds were identified in the strawberry initial substrate, strawberry wine, and strawberry vinegar, respectively. Four and 8 anthocyanin compounds were tentatively identified with high accuracy for the 1st time to be present in the beverages obtained by alcoholic fermentation and acetic fermentation of strawberry, respectively. Both, the total and the individual anthocyanin concentrations were decreased by both fermentation processes, affecting the alcoholic fermentation to a lesser extent (19%) than the acetic fermentation (91%). Indeed, several changes in color parameters have been assessed. The color of the wine and the vinegar made from strawberry changed during the fermentation process, varying from red to orange color, this fact is directly correlated with the decrease of anthocyanins compounds. © 2017 Institute of Food Technologists®.

Color identification and fuzzy reasoning based monitoring and controlling of fermentation process of branched chain amino acid

NASA Astrophysics Data System (ADS)

Ma, Lei; Wang, Yizhong; Xu, Qingyang; Huang, Huafang; Zhang, Rui; Chen, Ning

2009-11-01

The main production method of branched chain amino acid (BCAA) is microbial fermentation. In this paper, to monitor and to control the fermentation process of BCAA, especially its logarithmic phase, parameters such as the color of fermentation broth, culture temperature, pH, revolution, dissolved oxygen, airflow rate, pressure, optical density, and residual glucose, are measured and/or controlled and/or adjusted. The color of fermentation broth is measured using the HIS color model and a BP neural network. The network's input is the histograms of hue H and saturation S, and output is the color description. Fermentation process parameters are adjusted using fuzzy reasoning, which is performed by inference rules. According to the practical situation of BCAA fermentation process, all parameters are divided into four grades, and different fuzzy rules are established.

Lactate production as representative of the fermentation potential of Corynebacterium glutamicum 2262 in a one-step process.

PubMed

Khuat, Hoang Bao Truc; Kaboré, Abdoul Karim; Olmos, Eric; Fick, Michel; Boudrant, Joseph; Goergen, Jean-Louis; Delaunay, Stéphane; Guedon, Emmanuel

2014-01-01

The fermentative properties of thermo-sensitive strain Corynebacterium glutamicum 2262 were investigated in processes coupling aerobic cell growth and the anaerobic fermentation phase. In particular, the influence of two modes of fermentation on the production of lactate, the fermentation product model, was studied. In both processes, lactate was produced in significant amount, 27 g/L in batch culture, and up to 55.8 g/L in fed-batch culture, but the specific production rate in the fed-batch culture was four times lower than that in the batch culture. Compared to other investigated fermentation processes, our strategy resulted in the highest yield of lactic acid from biomass. Lactate production by C. glutamicum 2262 thus revealed the capability of the strain to produce various fermentation products from pyruvate.

[Progress in omics research of Aspergillus niger].

PubMed

Sui, Yufei; Ouyang, Liming; Lu, Hongzhong; Zhuang, Yingping; Zhang, Siliang

2016-08-25

Aspergillus niger, as an important industrial fermentation strain, is widely applied in the production of organic acids and industrial enzymes. With the development of diverse omics technologies, the data of genome, transcriptome, proteome and metabolome of A. niger are increasing continuously, which declared the coming era of big data for the research in fermentation process of A. niger. The data analysis from single omics and the comparison of multi-omics, to the integrations of multi-omics based on the genome-scale metabolic network model largely extends the intensive and systematic understanding of the efficient production mechanism of A. niger. It also provides possibilities for the reasonable global optimization of strain performance by genetic modification and process regulation. We reviewed and summarized progress in omics research of A. niger, and proposed the development direction of omics research on this cell factory.

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

PubMed

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

2013-08-01

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

The deep processing of seaweed industrial waste--Influence of several fermentation on seaweed waste of feed

NASA Astrophysics Data System (ADS)

Zhao, Shipeng; Zhang, Shuping

2018-02-01

This paper focuses on several factors on the effects of fermented seaweed feed, and obtains the optimal fermentation process through the analysis of nutrients. Through the experiment we can get, Seaweed waste fermented the best feed when adding 1% of microbial agents and 0.5% of corn powder, fermenting for 15 days.

40 CFR Table 4 to Subpart Cccc of... - Continuous Compliance With Emission Limitations

Code of Federal Regulations, 2011 CFR

2011-07-01

... CATEGORIES National Emission Standards for Hazardous Air Pollutants: Manufacturing of Nutritional Yeast Part... yeast in a fermentation stage (last (Trade), second-to-last (First Generation), or third-to-last (Stock... the applicable maximum concentration. 2. Each fed-batch fermenter producing yeast in a fermentation...

Effect of summer annuals on ruminal fermentation and methane output in continuous culture

USDA-ARS?s Scientific Manuscript database

Summer annuals (SA) provide forage during the summer “forage slump”, yet research on ruminal fermentation and CH4 output of SA is lacking. A 4-unit, dual-flow continuous culture fermentor system was used to assess nutrient digestibility, VFA production, bacterial protein synthesis, and CH4 output of...

76 FR 43489 - Deferral for CO2

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-20

.... 221320 Sewage treatment facilities. 562212 Solid waste landfills. Fermentation processes......... 325193... processors burning agricultural biomass residues, using fermentation processes, or producing/using biogas... treatment or manure management processes; CO 2 from fermentation during ethanol production or other...

Sterilization of fermentation vessels by ethanol/water mixtures

DOEpatents

Wyman, Charles E.

1999-02-09

A method for sterilizing process fermentation vessels with a concentrated alcohol and water mixture integrated in a fuel alcohol or other alcohol production facility. Hot, concentrated alcohol is drawn from a distillation or other purification stage and sprayed into the empty fermentation vessels. This sterilizing alcohol/water mixture should be of a sufficient concentration, preferably higher than 12% alcohol by volume, to be toxic to undesirable microorganisms. Following sterilization, this sterilizing alcohol/water mixture can be recovered back into the same distillation or other purification stage from which it was withdrawn. The process of this invention has its best application in, but is not limited to, batch fermentation processes, wherein the fermentation vessels must be emptied, cleaned, and sterilized following completion of each batch fermentation process.

Technique of ethanol food grade production with batch distillation and dehydration using starch-based adsorbent

NASA Astrophysics Data System (ADS)

Widjaja, Tri; Altway, Ali; Ni'mah, Hikmatun; Tedji, Namira; Rofiqah, Umi

2015-12-01

Development and innovation of ethanol food grade production are becoming the reasearch priority to increase economy growth. Moreover, the government of Indonesia has established regulation for increasing the renewable energy as primary energy. Sorghum is cerealia plant that contains 11-16% sugar that is optimum for fermentation process, it is potential to be cultivated, especially at barren area in Indonesia. The purpose of this experiment is to learn about the effect of microorganisms in fermentation process. Fermentation process was carried out batchwise in bioreactor and used 150g/L initial sugar concentration. Microorganisms used in this experiment are Zymomonas mobilis mutation (A3), Saccharomyces cerevisiae and mixed of Pichia stipitis. The yield of ethanol can be obtained from this experiment. For ethanol purification result, distillation process from fermentation process has been done to search the best operation condition for efficiency energy consumption. The experiment for purification was divided into two parts, which are distillation with structured packing steel wool and adsorption (dehydration) sequencely. In distillation part, parameters evaluation (HETP and pressure drop) of distillation column that can be used for scale up are needed. The experiment was operated at pressure of 1 atm. The distillation stage was carried out at 85 °C and reflux ratio of 0.92 with variety porosities of 20%, 40%, and 60%. Then the adsorption process was done at 120°C and two types of adsorbent, which are starch - based adsorbent with ingredient of cassava and molecular sieve 3A, were used. The adsorption process was then continued to purify the ethanol from impurities by using activated carbon. This research shows that the batch fermentation process with Zymomonas mobilis A3 obtain higher % yield of ethanol of 40,92%. In addition to that, for purification process, the best operation condition is by using 40% of porosity of stuctured packing steel wool in distillation stage and starch-based adsorbent in adsorption stage, which can obtain ethanol content of 92,15% with acetic acid percentage of 0,001% and the rest is water. This result is qualified for ethanol food grade specification which is between 90 - 94 % of ethanol with maximum percentage of acetic acid is 0,003%, and passes in fusel oil and isopropyl alcohol test.

Microbial diversity and their roles in the vinegar fermentation process.

PubMed

Li, Sha; Li, Pan; Feng, Feng; Luo, Li-Xin

2015-06-01

Vinegar is one of the oldest acetic acid-diluted solution products in the world. It is produced from any fermentable sugary substrate by various fermentation methods. The final vinegar products possess unique functions, which are endowed with many kinds of compounds formed in the fermentation process. The quality of vinegar is determined by many factors, especially by the raw materials and microbial diversity involved in vinegar fermentation. Given that metabolic products from the fermenting strains are directly related to the quality of the final products of vinegar, the microbial diversity and features of the dominant strains involved in different fermentation stages should be analyzed to improve the strains and stabilize fermentation. Moreover, although numerous microbiological studies have been conducted to examine the process of vinegar fermentation, knowledge about microbial diversity and their roles involved in fermentation is still fragmentary and not systematic enough. Therefore, in this review, the dominant microorganism species involved in the stages of alcoholic fermentation and acetic acid fermentation of dissimilar vinegars were summarized. We also summarized various physicochemical properties and crucial compounds in disparate types of vinegar. Furthermore, the merits and drawbacks of vital fermentation methods were generalized. Finally, we described in detail the relationships among microbial diversity, raw materials, fermentation methods, physicochemical properties, compounds, functionality, and final quality of vinegar. The integration of this information can provide us a detailed map about the microbial diversity and function involved in vinegar fermentation.

Effects of concentrate replacement by feed blocks on ruminal fermentation and microbial growth in goats and single-flow continuous-culture fermenters.

PubMed

Molina-Alcaide, E; Pascual, M R; Cantalapiedra-Hijar, G; Morales-García, E Y; Martín-García, A I

2009-04-01

The effect of replacing concentrate with 2 different feed blocks (FB) on ruminal fermentation and microbial growth was evaluated in goats and in single-flow continuous-culture fermenters. Diets consisted of alfalfa hay plus concentrate and alfalfa hay plus concentrate with 1 of the 2 studied FB. Three trials were carried out with 6 rumen-fistulated Granadina goats and 3 incubation runs in 6 single-flow continuous-culture fermenters. Experimental treatments were assigned randomly within each run, with 2 repetitions for each diet. At the end of each in vivo trial, the rumen contents were obtained for inoculating the fermenters. For each incubation run, the fermenters were inoculated with ruminal fluid from goats fed the same diet supplied to the corresponding fermenter flask. The average pH values, total and individual VFA, and NH(3)-N concentrations, and acetate:propionate ratios in the rumen of goats were not affected (P >or= 0.10) by diet, whereas the microbial N flow (MNF) and efficiency were affected (P or= 0.05), and total (P=0.02), NH(3) (P=0.005), and non-NH(3) (P=0.02) N flows, whereas the efficiency of VFA production was not affected (P=0.75). The effect of diet on MNF and efficiency depended on the bacterial pellet used as a reference. An effect (P<0.05) of diet on the composition of solid- and liquid-associated bacteria was observed. The compositions of liquid-associated bacteria in the fermenter contents and effluent were similar (P=0.05). Differences (P<0.001) between in vivo and in vitro values for most fermentation variables and bacterial pellet compositions were found. Partial replacement of the concentrate with FB did not greatly compromise carbohydrate fermentation in unproductive goats. However, this was not the case for MNF and efficiency. Differences between the results obtained in vivo and in vitro indicate a need to identify conditions in fermenters that allow better simulation of fermentation, microbial growth, and bacterial pellet composition in vivo. Reduced feeding cost could be achieved with the inclusion of FB in the diets of unproductive goats without altering rumen fermentation.

Fermentation process using specific oxygen uptake rates as a process control

DOEpatents

Van Hoek, Pim; Aristidou, Aristos; Rush, Brian J.

2016-08-30

Specific oxygen uptake (OUR) is used as a process control parameter in fermentation processes. OUR is determined during at least the production phase of a fermentation process, and process parameters are adjusted to maintain the OUR within desired ranges. The invention is particularly applicable when the fermentation is conducted using a microorganism having a natural PDC pathway that has been disrupted so that it no longer functions. Microorganisms of this sort often produce poorly under strictly anaerobic conditions. Microaeration controlled by monitoring OUR allows the performance of the microorganism to be optimized.

Fermentation process using specific oxygen uptake rates as a process control

DOEpatents

Van Hoek, Pim [Minnetonka, MN; Aristidou, Aristos [Maple Grove, MN; Rush, Brian [Minneapolis, MN

2011-05-10

Specific oxygen uptake (OUR) is used as a process control parameter in fermentation processes. OUR is determined during at least the production phase of a fermentation process, and process parameters are adjusted to maintain the OUR within desired ranges. The invention is particularly applicable when the fermentation is conducted using a microorganism having a natural PDC pathway that has been disrupted so that it no longer functions. Microorganisms of this sort often produce poorly under strictly anaerobic conditions. Microaeration controlled by monitoring OUR allows the performance of the microorganism to be optimized.

Fermentation process using specific oxygen uptake rates as a process control

DOEpatents

Hoek, Van; Pim, Aristidou [Minnetonka, MN; Aristos, Rush [Maple Grove, MN; Brian, [Minneapolis, MN

2007-06-19

Specific oxygen uptake (OUR) is used as a process control parameter in fermentation processes. OUR is determined during at least the production phase of a fermentation process, and process parameters are adjusted to maintain the OUR within desired ranges. The invention is particularly applicable when the fermentation is conducted using a microorganism having a natural PDC pathway that has been disrupted so that it no longer functions. Microorganisms of this sort often produce poorly under strictly anaerobic conditions. Microaeration controlled by monitoring OUR allows the performance of the microorganism to be optimized.

Fermentation process using specific oxygen uptake rates as a process control

DOEpatents

Van Hoek, Pim; Aristidou, Aristos; Rush, Brian

2014-09-09

Specific oxygen uptake (OUR) is used as a process control parameter in fermentation processes. OUR is determined during at least the production phase of a fermentation process, and process parameters are adjusted to maintain the OUR within desired ranges. The invention is particularly applicable when the fermentation is conducted using a microorganism having a natural PDC pathway that has been disrupted so that it no longer functions. Microorganisms of this sort often produce poorly under strictly anaerobic conditions. Microaeration controlled by monitoring OUR allows the performance of the microorganism to be optimized.

Approach of describing dynamic production of volatile fatty acids from sludge alkaline fermentation.

PubMed

Wang, Dongbo; Liu, Yiwen; Ngo, Huu Hao; Zhang, Chang; Yang, Qi; Peng, Lai; He, Dandan; Zeng, Guangming; Li, Xiaoming; Ni, Bing-Jie

2017-08-01

In this work, a mathematical model was developed to describe the dynamics of fermentation products in sludge alkaline fermentation systems for the first time. In this model, the impacts of alkaline fermentation on sludge disintegration, hydrolysis, acidogenesis, acetogenesis, and methanogenesis processes are specifically considered for describing the high-level formation of fermentation products. The model proposed successfully reproduced the experimental data obtained from five independent sludge alkaline fermentation studies. The modeling results showed that alkaline fermentation largely facilitated the disintegration, acidogenesis, and acetogenesis processes and severely inhibited methanogenesis process. With the pH increase from 7.0 to 10.0, the disintegration, acidogenesis, and acetogenesis processes respectively increased by 53%, 1030%, and 30% while methane production decreased by 3800%. However, no substantial effect on hydrolysis process was found. The model also indicated that the pathway of acetoclastic methanogenesis was more severely inhibited by alkaline condition than that of hydrogentrophic methanogenesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultrafiltration of hemicellulose hydrolysate fermentation broth

NASA Astrophysics Data System (ADS)

Kresnowati, M. T. A. P.; Desiriani, Ria; Wenten, I. G.

2017-03-01

Hemicelulosic material is often used as the main substrate to obtain high-value products such as xylose. The five carbon sugar, xylose, could be further processed by fermentation to produce xylitol. However, not only the hemicellulose hydrolysate fermentation broth contains xylitol, but also metabolite products, residual substances, biomass and mineral salts. Therefore, in order to obtain the end products, various separation processes are required to separate and purify the desired product from the fermentation broth. One of the most promising downstream processing methods of fermentation broth clarification is ultrafiltration due to its potential for energy saving and higher purity. In addition, ultrafiltration membrane has a high performance in separating inhibitory components in the fermentation broth. This paper assesses the influence of operating conditions; including trans-membrane pressure, velocity, pH of the fermentation broth solutions, and also to the xylitol concentration in the product. The challenges of the ultrafiltration process will be pointed out.

Reverse Osmosis Processing of Organic Model Compounds and Fermentation Broths

DTIC Science & Technology

2006-04-01

AFRL-ML-TY-TP-2007-4545 POSTPRINT REVERSE OSMOSIS PROCESSING OF ORGANIC MODEL COMPOUNDS AND FERMENTATION BROTHS Robert Diltz...TELEPHONE NUMBER (Include area code) Bioresource Technology 98 (2007) 686–695Reverse osmosis processing of organic model compounds and fermentation broths...December 2005; accepted 31 January 2006 Available online 4 April 2006Abstract Post-treatment of an anaerobic fermentation broth was evaluated using a 150

Yeast community associated with the solid state fermentation of traditional Chinese Maotai-flavor liquor.

PubMed

Wu, Qun; Chen, Liangqiang; Xu, Yan

2013-09-02

Yeasts are the most important group of microorganisms contributing to liquor quality in the solid-state fermentation process of Chinese Maotai-flavor liquor. There occurred a complex yeast community structure during this process, including stages of Daqu (the starter) making, stacking fermentation on the ground and liquor fermentation in the pits. In the Daqu making stage, few yeast strains accumulated. However, the stacking fermentation stage accumulated nine yeast species with different physio-biochemical characteristics. But only four species kept dominant until liquor fermentation, which were Zygosaccharomyces bailii, Saccharomyces cerevisiae, Pichia membranifaciens, and Schizosaccharomyces pombe, implying their important functions in liquor making. The four species tended to inhabit in different locations of the stack and pits during stacking and liquor fermentation, due to the condition heterogeneity of the solid-state fermentation, including the different fermentation temperature profiles and oxygen density in different locations. Moreover, yeast population was much larger in the upper layer than that in the middle and bottom layers in liquor fermentation, which was in accordance with the profile of reducing sugar consumption and ethanol production. This was a systematical investigation of yeast community structure dynamics in the Maotai-flavor liquor fermentation process. It would be of help to understand the fermentative mechanism in solid-state fermentation for Maotai-flavor liquor. © 2013.

The process-related dynamics of microbial community during a simulated fermentation of Chinese strong-flavored liquor.

PubMed

Zhang, Yanyan; Zhu, Xiaoyu; Li, Xiangzhen; Tao, Yong; Jia, Jia; He, Xiaohong

2017-09-15

Famous Chinese strong-flavored liquor (CSFL) is brewed by microbial consortia in a special fermentation pit (FT). However, the fermentation process was not fully understood owing to the complicate community structure and metabolism. In this study, the process-related dynamics of microbial communities and main flavor compounds during the 70-day fermentation process were investigated in a simulated fermentation system. A three-phase model was proposed to characterize the process of the CSFL fermentation. (i) In the early fermentation period (1-23 days), glucose was produced from macromolecular carbohydrates (e.g., starch). The prokaryotic diversity decreased significantly. The Lactobacillaceae gradually predominated in the prokaryotic community. In contrast, the eukaryotic diversity rose remarkably in this stage. Thermoascus, Aspergillus, Rhizopus and unidentified Saccharomycetales were dominant eukaryotic members. (ii) In the middle fermentation period (23-48 days), glucose concentration decreased while lactate acid and ethanol increased significantly. Prokaryotic community was almost dominated by the Lactobacillus, while eukaryotic community was mainly comprised of Thermoascus, Emericella and Aspergillus. (iii) In the later fermentation period (48-70 days), the concentrations of ethyl esters, especially ethyl caproate, increased remarkably. The CSFL fermentation could undergo three stages: saccharification, glycolysis and esterification. Saccharomycetales, Monascus, and Rhizopus were positively correlated to glucose concentration (P < 0.05), highlighting their important roles in the starch saccharification. The Lactobacillaceae, Bacilli, Botryotinia, Aspergillus, unidentified Pleosporales and Capnodiales contributed to the glycolysis and esterification, because they were positively correlated to most organic acids and ethyl esters (P < 0.05). Additionally, four genera, including Emericella, Suillus, Mortierella and Botryotinia, that likely played key roles in fermentation, were observed firstly. This study observed comprehensive dynamics of microbial communities during the CSFL fermentation, and it further revealed the correlations between some crucial microorganisms and flavoring chemicals (FCs). The results from this study help to design effective strategies to manipulate microbial consortia for fermentation process optimization in the CSFL brew practice.

[On-line monitoring of biomass in 1,3-propanediol fermentation by Fourier-transformed near-infrared spectra analysis].

PubMed

Wang, Lu; Liu, Tao; Chen, Yang; Sun, Yaqin; Xiu, Zhilong

2017-01-25

Biomass is an important parameter reflecting the fermentation dynamics. Real-time monitoring of biomass can be used to control and optimize a fermentation process. To overcome the deficiencies of measurement delay and manual errors from offline measurement, we designed an experimental platform for online monitoring the biomass during a 1,3-propanediol fermentation process, based on using the fourier-transformed near-infrared (FT-NIR) spectra analysis. By pre-processing the real-time sampled spectra and analyzing the sensitive spectra bands, a partial least-squares algorithm was proposed to establish a dynamic prediction model for the biomass change during a 1,3-propanediol fermentation process. The fermentation processes with substrate glycerol concentrations of 60 g/L and 40 g/L were used as the external validation experiments. The root mean square error of prediction (RMSEP) obtained by analyzing experimental data was 0.341 6 and 0.274 3, respectively. These results showed that the established model gave good prediction and could be effectively used for on-line monitoring the biomass during a 1,3-propanediol fermentation process.

Physico-chemical characterization of natural fermentation process of Conservolea and Kalamàta table olives and developement of a protocol for the pre-selection of fermentation starters.

PubMed

Bleve, Gianluca; Tufariello, Maria; Durante, Miriana; Grieco, Francesco; Ramires, Francesca Anna; Mita, Giovanni; Tasioula-Margari, Maria; Logrieco, Antonio Francesco

2015-04-01

Table olives are one of the most important traditional fermented vegetables in Europe and their world consumption is constantly increasing. Conservolea and Kalamàta are the most important table olives Greek varieties. In the Greek system, the final product is obtained by spontaneous fermentations, without any chemical debittering treatment. This natural fermentation process is not predictable and strongly influenced by the physical-chemical conditions and by the presence of microorganisms contaminating the olives. Natural fermentations of Conservolea and Kalamàta cultivars black olives were studied in order to determine microbiological, biochemical and chemical evolution during the process. Following the process conditions generally used by producers, in both cultivars, yeasts were detected throughout the fermentation, whereas lactic acid bacteria (LAB) appeared in the last staged of the process. A new optimized specific protocol was developed to select autochthonous yeast and LAB isolates that can be good candidates as starters. These microorganisms were pre-selected for their ability to adapt to model brines, to have beta-glucosidase activity, not to produce biogenic amines. Chemical compounds deriving by microbiological activities and associated to the three different phases (30, 90 and 180 days) of the fermentation process were identified and were proposed as chemical descriptors to follow the fermentation progress. Copyright © 2014 Elsevier Ltd. All rights reserved.

Production of acids and alcohols from syngas in a two-stage continuous fermentation process.

PubMed

Abubackar, Haris Nalakath; Veiga, María C; Kennes, Christian

2018-04-01

A two-stage continuous system with two stirred tank reactors in series was utilized to perform syngas fermentation using Clostridium carboxidivorans. The first bioreactor (bioreactor 1) was maintained at pH 6 to promote acidogenesis and the second one (bioreactor 2) at pH 5 to stimulate solventogenesis. Both reactors were operated in continuous mode by feeding syngas (CO:CO 2 :H 2 :N 2 ; 30:10:20:40; vol%) at a constant flow rate while supplying a nutrient medium at different flow rates of 8.1, 15, 22 and 30 ml/h. A cell recycling unit was added to bioreactor 2 in order to recycle the cells back to the reactor, maintaining the OD 600 around 1 in bioreactor 2 throughout the experimental run. When comparing the flow rates, the best results in terms of solvent production were obtained with a flow rate of 22 ml/h, reaching the highest average outlet concentration for alcohols (1.51 g/L) and the most favorable alcohol/acid ratio of 0.32. Copyright © 2018 Elsevier Ltd. All rights reserved.

Monitoring the microbial community during solid-state acetic acid fermentation of Zhenjiang aromatic vinegar.

PubMed

Xu, Wei; Huang, Zhiyong; Zhang, Xiaojun; Li, Qi; Lu, Zhenming; Shi, Jinsong; Xu, Zhenghong; Ma, Yanhe

2011-09-01

Zhenjiang aromatic vinegar is one of the most famous Chinese traditional vinegars. In this study, change of the microbial community during its fermentation process was investigated. DGGE results showed that microbial community was comparatively stable, and the diversity has a disciplinary series of changes during the fermentation process. It was suggested that domestication of microbes and unique cycle-inoculation style used in the fermentation of Zhenjiang aromatic vinegar were responsible for comparatively stable of the microbial community. Furthermore, two clone libraries were constructed. The results showed that bacteria presented in the fermentation belonged to genus Lactobacillus, Acetobacter, Gluconacetobacter, Staphylococcus, Enterobacter, Pseudomonas, Flavobacterium and Sinorhizobium, while the fungi were genus Saccharomyces. DGGE combined with clone library analysis was an effective and credible technique for analyzing the microbial community during the fermentation process of Zhenjiang aromatic vinegar. Real-time PCR results suggested that the biomass showed a "system microbes self-domestication" process in the first 5 days, then reached a higher level at the 7th day before gradually decreasing until the fermentation ended at the 20th day. This is the first report to study the changes of microbial community during fermentation process of Chinese traditional solid-state fermentation of vinegar. Copyright © 2011 Elsevier Ltd. All rights reserved.

Microbial bioinformatics for food safety and production

PubMed Central

Alkema, Wynand; Boekhorst, Jos; Wels, Michiel

2016-01-01

In the production of fermented foods, microbes play an important role. Optimization of fermentation processes or starter culture production traditionally was a trial-and-error approach inspired by expert knowledge of the fermentation process. Current developments in high-throughput ‘omics’ technologies allow developing more rational approaches to improve fermentation processes both from the food functionality as well as from the food safety perspective. Here, the authors thematically review typical bioinformatics techniques and approaches to improve various aspects of the microbial production of fermented food products and food safety. PMID:26082168

75 FR 81868 - Approval and Promulgation of Implementation Plans; Kentucky: Prevention of Significant...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-29

... ethanol through a natural fermentation process from the definition of ``chemical process plants'' in the... through a natural fermentation process from the definition of ``chemical process plants'' in the major NSR... facilities producing ethanol by natural fermentation under the North American Industry Classification System...

Effects of reflux ratio and feed conditions for the purification of bioethanol in a continuous distillation column

NASA Astrophysics Data System (ADS)

Dasan, Y. K.; Abdullah, M. A.; Bhat, A. H.

2014-10-01

Continuous distillation column was used for the purification of bioethanol from fermentation of molasses using Saccharomyces cerevisia. Bioethanol produced was at 8.32% (v/v) level. The efficiency of continuous distillation process was evaluated based on reflux ratio, and feed condition. The lab results were validated using COFE simulation Software. The analyses showed that both reflux ratio and feed condition had significant effects on the distillation process. Stages increased from 1.79 to 2.26 as the reflux ratio was decreased from 90% to 45% and the saturated feed produced lower mole fraction of desired product. We concluded that the lower reflux ratio with cold feed condition was suitable for higher mole fraction of top product.

Understanding Gut Fermentation Syndrome in the Psychiatric Evaluation of Patients with Suspected Alcohol Use Disorder

DTIC Science & Technology

2017-10-18

Fermentation Syndrome in the Psychiatric Evaluation of Patients with Suspected Alcohol Use Disorder Sb. GRANT NUMBER Sc. PROGRAM ELEMENT NUMBER 6...by ANSI Std. Z39.18 Adobe Professional 7. 0 Introduction Gut Fermentation Syndrome, also known as auto- brewery syndrome, is a phenomenon not well...patient stated abstinence from alcohol use and that Gut Fermentation Syndrome was the cause of continually elevated blood alcohol levels. We will

Sterilization of fermentation vessels by ethanol/water mixtures

DOEpatents

Wyman, C.E.

1999-02-09

A method is described for sterilizing process fermentation vessels with a concentrated alcohol and water mixture integrated in a fuel alcohol or other alcohol production facility. Hot, concentrated alcohol is drawn from a distillation or other purification stage and sprayed into the empty fermentation vessels. This sterilizing alcohol/water mixture should be of a sufficient concentration, preferably higher than 12% alcohol by volume, to be toxic to undesirable microorganisms. Following sterilization, this sterilizing alcohol/water mixture can be recovered back into the same distillation or other purification stage from which it was withdrawn. The process of this invention has its best application in, but is not limited to, batch fermentation processes, wherein the fermentation vessels must be emptied, cleaned, and sterilized following completion of each batch fermentation process. 2 figs.

Effect of oilseed source on ruminal fermentation and methane production of a grass-legume diet in continuous culture

USDA-ARS?s Scientific Manuscript database

Addition of oilseeds to pasture-based ruminant diets has been shown to decrease enteric CH4 emissions. However, little research has directly compared the effect of oilseed source on ruminal fermentation and Methane (CH4) production. A 4-unit continuous culture fermentor system was used to test 4 oil...

Improvement of the antioxidant and hypolipidaemic effects of cowpea flours (Vigna unguiculata) by fermentation: results of in vitro and in vivo experiments.

PubMed

Kapravelou, Garyfallia; Martínez, Rosario; Andrade, Ana M; López Chaves, Carlos; López-Jurado, María; Aranda, Pilar; Arrebola, Francisco; Cañizares, Francisco J; Galisteo, Milagros; Porres, Jesús M

2015-04-01

The antioxidant capacity and hypolipidaemic effects of Vigna unguiculata, as well as their potential improvement by different fermentation and thermal processes were studied using in vitro and in vivo methods. Phenolic content and reducing capacity of legume acetone extract were significantly increased by different fermentation processes, and by the thermal treatment of fermented legume flours. TBARS inhibiting capacity was increased by fermentation but not by thermal treatment. A higher ability to decrease Cu(2+)/H2O2-induced electrophoretic mobility of LDL was found in fermented when compared to raw legume extracts, and a higher protective effect on short term metabolic status of HT-29 cells was found for raw and lactobacillus-fermented Vigna followed by naturally fermented Vigna extracts. Significant improvements in plasma antioxidant capacity and hepatic activity of antioxidant enzymes were observed in rats that consumed fermented legume flours when compared to the untreated legume or a casein-methionine control diet. In addition, liver weight and plasma levels of cholesterol and triglycerides were also positively affected by untreated or naturally fermented Vigna. V. unguiculata has demonstrated its potential as a functional food with interesting antioxidant and lipid lowering properties, which can be further augmented by fermentation processes associated or not to thermal processing. © 2014 Society of Chemical Industry.

Attainable region analysis for continuous production of second generation bioethanol

PubMed Central

2013-01-01

Background Despite its semi-commercial status, ethanol production from lignocellulosics presents many complexities not yet fully solved. Since the pretreatment stage has been recognized as a complex and yield-determining step, it has been extensively studied. However, economic success of the production process also requires optimization of the biochemical conversion stage. This work addresses the search of bioreactor configurations with improved residence times for continuous enzymatic saccharification and fermentation operations. Instead of analyzing each possible configuration through simulation, we apply graphical methods to optimize the residence time of reactor networks composed of steady-state reactors. Although this can be easily made for processes described by a single kinetic expression, reactions under analysis do not exhibit this feature. Hence, the attainable region method, able to handle multiple species and its reactions, was applied for continuous reactors. Additionally, the effects of the sugars contained in the pretreatment liquor over the enzymatic hydrolysis and simultaneous saccharification and fermentation (SSF) were assessed. Results We obtained candidate attainable regions for separate enzymatic hydrolysis and fermentation (SHF) and SSF operations, both fed with pretreated corn stover. Results show that, despite the complexity of the reaction networks and underlying kinetics, the reactor networks that minimize the residence time can be constructed by using plug flow reactors and continuous stirred tank reactors. Regarding the effect of soluble solids in the feed stream to the reactor network, for SHF higher glucose concentration and yield are achieved for enzymatic hydrolysis with washed solids. Similarly, for SSF, higher yields and bioethanol titers are obtained using this substrate. Conclusions In this work, we demonstrated the capabilities of the attainable region analysis as a tool to assess the optimal reactor network with minimum residence time applied to the SHF and SSF operations for lignocellulosic ethanol production. The methodology can be readily modified to evaluate other kinetic models of different substrates, enzymes and microorganisms when available. From the obtained results, the most suitable reactor configuration considering residence time and rheological aspects is a continuous stirred tank reactor followed by a plug flow reactor (both in SSF mode) using washed solids as substrate. PMID:24286451

Attainable region analysis for continuous production of second generation bioethanol.

PubMed

Scott, Felipe; Conejeros, Raúl; Aroca, Germán

2013-11-29

Despite its semi-commercial status, ethanol production from lignocellulosics presents many complexities not yet fully solved. Since the pretreatment stage has been recognized as a complex and yield-determining step, it has been extensively studied. However, economic success of the production process also requires optimization of the biochemical conversion stage. This work addresses the search of bioreactor configurations with improved residence times for continuous enzymatic saccharification and fermentation operations. Instead of analyzing each possible configuration through simulation, we apply graphical methods to optimize the residence time of reactor networks composed of steady-state reactors. Although this can be easily made for processes described by a single kinetic expression, reactions under analysis do not exhibit this feature. Hence, the attainable region method, able to handle multiple species and its reactions, was applied for continuous reactors. Additionally, the effects of the sugars contained in the pretreatment liquor over the enzymatic hydrolysis and simultaneous saccharification and fermentation (SSF) were assessed. We obtained candidate attainable regions for separate enzymatic hydrolysis and fermentation (SHF) and SSF operations, both fed with pretreated corn stover. Results show that, despite the complexity of the reaction networks and underlying kinetics, the reactor networks that minimize the residence time can be constructed by using plug flow reactors and continuous stirred tank reactors. Regarding the effect of soluble solids in the feed stream to the reactor network, for SHF higher glucose concentration and yield are achieved for enzymatic hydrolysis with washed solids. Similarly, for SSF, higher yields and bioethanol titers are obtained using this substrate. In this work, we demonstrated the capabilities of the attainable region analysis as a tool to assess the optimal reactor network with minimum residence time applied to the SHF and SSF operations for lignocellulosic ethanol production. The methodology can be readily modified to evaluate other kinetic models of different substrates, enzymes and microorganisms when available. From the obtained results, the most suitable reactor configuration considering residence time and rheological aspects is a continuous stirred tank reactor followed by a plug flow reactor (both in SSF mode) using washed solids as substrate.

Koji--where East meets West in fermentation.

PubMed

Zhu, Yang; Tramper, Johannes

2013-12-01

Almost all biotechnological processes originate from traditional food fermentations, i.e. the many indigenous processes that can be found already in the written history of thousands of years ago. We still consume many of these fermented foods and beverages on a daily basis today. The evolution of these traditional processes, in particular since the 19th century, stimulated and influenced the development of modern biotechnological processes. In return, the development of modern biotechnology and related advanced techniques will no doubt improve the process, the product quality and the safety of our favourite fermented foods and beverages. In this article, we describe the relationship between these traditional food fermentations and modern biotechnology. Using Koji and its derived product soy sauce as examples, we address the mutual influences that will provide us with a better future concerning the quality, safety and nutritional effect of many fermented food products. © 2013.

Optimal design and experimental validation of a simulated moving bed chromatography for continuous recovery of formic acid in a model mixture of three organic acids from Actinobacillus bacteria fermentation.

PubMed

Park, Chanhun; Nam, Hee-Geun; Lee, Ki Bong; Mun, Sungyong

2014-10-24

The economically-efficient separation of formic acid from acetic acid and succinic acid has been a key issue in the production of formic acid with the Actinobacillus bacteria fermentation. To address this issue, an optimal three-zone simulated moving bed (SMB) chromatography for continuous separation of formic acid from acetic acid and succinic acid was developed in this study. As a first step for this task, the adsorption isotherm and mass-transfer parameters of each organic acid on the qualified adsorbent (Amberchrom-CG300C) were determined through a series of multiple frontal experiments. The determined parameters were then used in optimizing the SMB process for the considered separation. During such optimization, the additional investigation for selecting a proper SMB port configuration, which could be more advantageous for attaining better process performances, was carried out between two possible configurations. It was found that if the properly selected port configuration was adopted in the SMB of interest, the throughout and the formic-acid product concentration could be increased by 82% and 181% respectively. Finally, the optimized SMB process based on the properly selected port configuration was tested experimentally using a self-assembled SMB unit with three zones. The SMB experimental results and the relevant computer simulation verified that the developed process in this study was successful in continuous recovery of formic acid from a ternary organic-acid mixture of interest with high throughput, high purity, high yield, and high product concentration. Copyright © 2014 Elsevier B.V. All rights reserved.

Yeast Immobilization Systems for Alcoholic Wine Fermentations: Actual Trends and Future Perspectives

PubMed Central

Moreno-García, Jaime; García-Martínez, Teresa; Mauricio, Juan C.; Moreno, Juan

2018-01-01

Yeast immobilization is defined as the physical confinement of intact cells to a region of space with conservation of biological activity. The use of these methodologies for alcoholic fermentation (AF) offers many advantages over the use of the conventional free yeast cell method and different immobilization systems have been proposed so far for different applications, like winemaking. The most studied methods for yeast immobilization include the use of natural supports (e.g., fruit pieces), organic supports (e.g., alginate), inorganic (e.g., porous ceramics), membrane systems, and multi-functional agents. Some advantages of the yeast-immobilization systems include: high cell densities, product yield improvement, lowered risk of microbial contamination, better control and reproducibility of the processes, as well as reuse of the immobilization system for batch fermentations and continuous fermentation technologies. However, these methods have some consequences on the behavior of the yeasts, affecting the final products of the fermentative metabolism. This review compiles current information about cell immobilizer requirements for winemaking purposes, the immobilization methods applied to the production of fermented beverages to date, and yeast physiological consequences of immobilization strategies. Finally, a recent inter-species immobilization methodology has been revised, where yeast cells are attached to the hyphae of a Generally Recognized As Safe fungus and remain adhered following loss of viability of the fungus. The bio-capsules formed with this method open new and promising strategies for alcoholic beverage production (wine and low ethanol content beverages). PMID:29497415

Utilization of radiation technique on the saccharification and fermentation of biomass

NASA Astrophysics Data System (ADS)

Kaetsu, I.; Kumakura, M.; Fujimura, T.; Yoshii, F.; Kojima, T.; Tamada, M.

The application of irradiation technique to the process of saccharification and subsequent fermentation of cellulosic wastes such as chaff and rice straw to obtain ethanol, was investigated. It was found that when waste raw materials were irradiated by ?-ray or electron beam, they became accessible to the subsequent enzymatic saccharification reaction. Irradiation of 10 7-10 8 Rad was enough for this effect. Some kind of additives reduced necessary dosage for this pretreatment. Cellulase, Trichoderma reesei which produce cellulase, and yeast were immobilized as biocatalysts for biomass conversion by radiation-induced polymerization of glass-forming monomer at low temperature. The immobilized cellulase showed almost same activity of glucose production as the native cellulase. Continuous saccharification reaction was carried out by using the immobilized cellulase. The immobilized Trichoderma reesei and the immobilized yeast showed almost same activity as the intact biocatalysts. It was concluded that the continuous saccharification and subsequent fermentation could be carried out effectively by using the immobilized biocatalysts. Spinach chloroplasts were immobilized by the same method as the first step for the conversion of water into hydrogen gas using solar energy. The immobilized chloroplasts kept the O 2 evolution activity in storage more than 30 days at 4°C. Thermostatility of chloroplasts was also improved greatly by the immobilization.

Flexible biorefinery for producing fermentation sugars, lignin and pulp from corn stover.

PubMed

Kadam, Kiran L; Chin, Chim Y; Brown, Lawrence W

2008-05-01

A new biorefining process is presented that embodies green processing and sustainable development. In the spirit of a true biorefinery, the objective is to convert agricultural residues and other biomass feedstocks into value-added products such as fuel ethanol, dissolving pulp, and lignin for resin production. The continuous biomass fractionation process yields a liquid stream rich in hemicellulosic sugars, a lignin-rich liquid stream, and a solid cellulose stream. This paper generally discusses potential applications of the three streams and specifically provides results on the evaluation of the cellulose stream from corn stover as a source of fermentation sugars and specialty pulp. Enzymatic hydrolysis of this relatively pure cellulose stream requires significantly lower enzyme loadings because of minimal enzyme deactivation from nonspecific binding to lignin. A correlation was shown to exist between lignin removal efficiency and enzymatic digestibility. The cellulose produced was also demonstrated to be a suitable replacement for hardwood pulp, especially in the top ply of a linerboard. Also, the relatively pure nature of the cellulose renders it suitable as raw material for making dissolving pulp. This pulping approach has significantly smaller environmental footprint compared to the industry-standard kraft process because no sulfur- or chlorine-containing compounds are used. Although this option needs some minimal post-processing, it produces a higher value commodity than ethanol and, unlike ethanol, does not need extensive processing such as hydrolysis or fermentation. Potential use of low-molecular weight lignin as a raw material for wood adhesive production is discussed as well as its use as cement and feed binder. As a baseline application the hemicellulosic sugars captured in the hydrolyzate liquor can be used to produce ethanol, but potential utilization of xylose for xylitol fermentation is also feasible. Markets and values of these applications are juxtaposed with market penetration and saturation.

A hollow-fiber membrane extraction process for recovery and separation of lactic acid from aqueous solution.

PubMed

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.

Effect of dilution rate and nutrients addition on the fermentative capability and synthesis of aromatic compounds of two indigenous strains of Saccharomyces cerevisiae in continuous cultures fed with Agave tequilana juice.

PubMed

Morán-Marroquín, G A; Córdova, J; Valle-Rodríguez, J O; Estarrón-Espinosa, M; Díaz-Montaño, D M

2011-11-15

Knowledge of physiological behavior of indigenous tequila yeast used in fermentation process is still limited. Yeasts have significant impact on the productivity fermentation process as well as the sensorial characteristics of the alcoholic beverage. For these reasons a better knowledge of the physiological and metabolic features of these yeasts is required. The effects of dilution rate, nitrogen and phosphorus source addition and micro-aeration on growth, fermentation and synthesis of volatile compounds of two native Saccharomyces cerevisiae strains, cultured in continuous fed with Agave tequilana juice were studied. For S1 and S2 strains, maximal concentrations of biomass, ethanol, consumed sugars, alcohols and esters were obtained at 0.04 h⁻¹. Those concentrations quickly decreased as D increased. For S. cerevisiae S1 cultures (at D=0.08 h⁻¹) supplemented with ammonium phosphate (AP) from 1 to 4 g/L, concentrations of residual sugars decreased from 29.42 to 17.60 g/L and ethanol increased from 29.63 to 40.08 g/L, respectively. The S1 culture supplemented with AP was then micro-aerated from 0 to 0.02 vvm, improving all the kinetics parameters: biomass, ethanol and glycerol concentrations increased from 5.66, 40.08 and 3.11 g/L to 8.04, 45.91 and 4.88 g/L; residual sugars decreased from 17.67 g/L to 4.48 g/L; and rates of productions of biomass and ethanol, and consumption of sugars increased from 0.45, 3.21 and 7.33 g/L·h to 0.64, 3.67 and 8.38 g/L·h, respectively. Concentrations of volatile compounds were also influenced by the micro-aeration rate. Ester and alcohol concentrations were higher, in none aerated and in aerated cultures respectively. Copyright © 2011. Published by Elsevier B.V.

Recovery of lactic acid from the pretreated fermentation broth based on a novel hyper-cross-linked meso-micropore resin: Modeling.

PubMed

Song, Mingkai; Jiao, Pengfei; Qin, Taotao; Jiang, Kangkang; Zhou, Jingwei; Zhuang, Wei; Chen, Yong; Liu, Dong; Zhu, Chenjie; Chen, Xiaochun; Ying, Hanjie; Wu, Jinglan

2017-10-01

An innovative benign process for recovery lactic acid from its fermentation broth is proposed using a novel hyper-cross-linked meso-micropore resin and water as eluent. This work focuses on modeling the competitive adsorption behaviors of glucose, lactic acid and acetic acid ternary mixture and explosion of the adsorption mechanism. The characterization results showed the resin had a large BET surface area and specific pore structure with hydrophobic properties. By analysis of the physicochemical properties of the solutes and the resin, the mechanism of the separation is proposed as hydrophobic effect and size-exclusion. Subsequently three chromatographic models were applied to predict the competitive breakthrough curves of the ternary mixture under different operating conditions. The pore diffusion was the major limiting factor for the adsorption process, which was consistent with the BET results. The novel HD-06 resin can be a good potential adsorbent for the future SMB continuous separation process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Influence of dietary fiber on inflammatory bowel disease and colon cancer: importance of fermentation pattern.

PubMed

Rose, Devin J; DeMeo, Mark T; Keshavarzian, Ali; Hamaker, Bruce R

2007-02-01

The benefits of dietary fiber on inflammatory bowel disease may be related to the fermentative production of butyrate in the colon, which appears to decrease the inflammatory response. The benefits of dietary fiber against colon cancer may be related to both fermentative and non-fermentative processes, although poorly fermentable fibers appear more influential. Dietary fiber fermentation profiles are important in determining optimal fibers for colonic health, and may be a function of structure, processing conditions, and other food components. A greater understanding of the relationships between fermentation rate and dietary fiber structure would allow for development of dietary fibers for optimum colonic health.

Radiation induces acid tolerance of Clostridium tyrobutyricum and enhances bioproduction of butyric acid through a metabolic switch

PubMed Central

2014-01-01

Background Butyric acid as a renewable resource has become an increasingly attractive alternative to petroleum-based fuels. Clostridium tyrobutyricum ATCC 25755T is well documented as a fermentation strain for the production of acids. However, it has been reported that butyrate inhibits its growth, and the accumulation of acetate also inhibits biomass synthesis, making production of butyric acid from conventional fermentation processes economically challenging. The present study aimed to identify whether irradiation of C. tyrobutyricum cells makes them more tolerant to butyric acid inhibition and increases the production of butyrate compared with wild type. Results In this work, the fermentation kinetics of C. tyrobutyricum cultures after being classically adapted for growth at 3.6, 7.2 and 10.8 g·L-1 equivalents were studied. The results showed that, regardless of the irradiation used, there was a gradual inhibition of cell growth at butyric acid concentrations above 10.8 g·L-1, with no growth observed at butyric acid concentrations above 3.6 g·L-1 for the wild-type strain during the first 54 h of fermentation. The sodium dodecyl sulfate polyacrylamide gel electrophoresis also showed significantly different expression levels of proteins with molecular mass around the wild-type and irradiated strains. The results showed that the proportion of proteins with molecular weights of 85 and 106 kDa was much higher for the irradiated strains. The specific growth rate decreased by 50% (from 0.42 to 0.21 h-1) and the final concentration of butyrate increased by 68% (from 22.7 to 33.4 g·L-1) for the strain irradiated at 114 AMeV and 40 Gy compared with the wild-type strains. Conclusions This study demonstrates that butyric acid production from glucose can be significantly improved and enhanced by using 12C6+ heavy ion-irradiated C. tyrobutyricum. The approach is economical, making it competitive compared with similar fermentation processes. It may prove useful as a first step in a combined method employing long-term continuous fermentation of acid-production processes. PMID:24533663

Radiation induces acid tolerance of Clostridium tyrobutyricum and enhances bioproduction of butyric acid through a metabolic switch.

PubMed

Zhou, Xiang; Lu, Xi-Hong; Li, Xue-Hu; Xin, Zhi-Jun; Xie, Jia-Rong; Zhao, Mei-Rong; Wang, Liang; Du, Wen-Yue; Liang, Jian-Ping

2014-02-18

Butyric acid as a renewable resource has become an increasingly attractive alternative to petroleum-based fuels. Clostridium tyrobutyricum ATCC 25755T is well documented as a fermentation strain for the production of acids. However, it has been reported that butyrate inhibits its growth, and the accumulation of acetate also inhibits biomass synthesis, making production of butyric acid from conventional fermentation processes economically challenging. The present study aimed to identify whether irradiation of C. tyrobutyricum cells makes them more tolerant to butyric acid inhibition and increases the production of butyrate compared with wild type. In this work, the fermentation kinetics of C. tyrobutyricum cultures after being classically adapted for growth at 3.6, 7.2 and 10.8 g·L-1 equivalents were studied. The results showed that, regardless of the irradiation used, there was a gradual inhibition of cell growth at butyric acid concentrations above 10.8 g·L-1, with no growth observed at butyric acid concentrations above 3.6 g·L-1 for the wild-type strain during the first 54 h of fermentation. The sodium dodecyl sulfate polyacrylamide gel electrophoresis also showed significantly different expression levels of proteins with molecular mass around the wild-type and irradiated strains. The results showed that the proportion of proteins with molecular weights of 85 and 106 kDa was much higher for the irradiated strains. The specific growth rate decreased by 50% (from 0.42 to 0.21 h-1) and the final concentration of butyrate increased by 68% (from 22.7 to 33.4 g·L-1) for the strain irradiated at 114 AMeV and 40 Gy compared with the wild-type strains. This study demonstrates that butyric acid production from glucose can be significantly improved and enhanced by using 12C6+ heavy ion-irradiated C. tyrobutyricum. The approach is economical, making it competitive compared with similar fermentation processes. It may prove useful as a first step in a combined method employing long-term continuous fermentation of acid-production processes.

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

PubMed

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

2014-06-01

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

Effect of pH fermentation on production bioethanol from jackfruit seeds (Artocarpus heterophyllus) through separate fermentation hydrolysis method

NASA Astrophysics Data System (ADS)

Arif, A. R.; Natsir, H.; Rohani, H.; Karim, A.

2018-03-01

Bioethanol is one of the alternative energy sourced from natural products containing carbohydrates through hydrolysis and fermentation process. Jackfruit seeds is one of the feedstock that contain high carbohydrate content but less utilized. The aims of this study to determine the effect of pH hydrolysis in the process of production bioethanol from jackfruit seeds (Artocarpus heterophyllus) through separate fermentation hydrolysis (SHF) method. The hydrolysis process uses H2SO4 as a hydrolyzing agent. The fermentation process used Saccharomyces cereviceae as a fermentor with a variation of pH 2,3 4 and 5 for 70 hours. The results showed that glucose content of 75% and pH 3 was the optimum pH of fermentation with the content of bioethanol 57.94%. The fermentation stage has an important role in increasing the levels of glucose and bioethanol in linear. The content of glucose and bioethanol of jackfruit seeds showed a great potential for development as the feedstock in bioethanol production.

Transcriptional Regulation of Aerobic Metabolism in Pichia pastoris Fermentation

PubMed Central

Zhang, Biao; Li, Baizhi; Chen, Dai; Zong, Jie; Sun, Fei; Qu, Huixin; Liang, Chongyang

2016-01-01

In this study, we investigated the classical fermentation process in Pichia pastoris based on transcriptomics. We utilized methanol in pichia yeast cell as the focus of our study, based on two key steps: limiting carbon source replacement (from glycerol to methonal) and fermentative production of exogenous proteins. In the former, the core differential genes in co-expression net point to initiation of aerobic metabolism and generation of peroxisome. The transmission electron microscope (TEM) results showed that yeast gradually adapted methanol induction to increased cell volume, and decreased density, via large number of peroxisomes. In the fermentative production of exogenous proteins, the Gene Ontology (GO) mapping results show that PAS_chr2-1_0582 played a vital role in regulating aerobic metabolic drift. In order to confirm the above results, we disrupted PAS_chr2-1_0582 by homologous recombination. Alcohol consumption was equivalent to one fifth of the normal control, and fewer peroxisomes were observed in Δ0582 strain following methanol induction. In this study we determined the important core genes and GO terms regulating aerobic metabolic drift in Pichia, as well as developing new perspectives for the continued development within this field. PMID:27537181

Biochemical Process Development and Integration | Bioenergy | NREL

Science.gov Websites

Process Development We develop and scale fermentation processes that produce fuels and chemicals from guide experimental designs. Our newly updated fermentation laboratory houses 38 bench-scale fermentors current projects cover the fermentation spectrum including anaerobic, micro-aerobic, aerobic, and gas-to

Short communication: effect of oilseed supplementation of an herbage diet on ruminal fermentation in continuous culture

USDA-ARS?s Scientific Manuscript database

A four-unit continuous culture fermentor system was used to evaluate the effects of oilseed supplementation of an herbage-based diet on ruminal fermentation. Treatments were randomly assigned to fermentors in a 4 x 4 Latin square design with 7 d for diet adaptation and 3 d for data and sample collec...

Molasses supplementation of grazing dairy cows: summary of case study, continuous culture fermenter trials, and controlled research farm study

USDA-ARS?s Scientific Manuscript database

This fact sheet summarizes the results of a three-tiered research approach (case study, two continuous culture fermenter studies, and a controlled research farm study) to evaluate molasses as an alternative supplement source for grazing dairy cows. A two-year case study of a New York organic dairy f...

40 CFR 63.2165 - How do I demonstrate initial compliance with the emission limitations if I monitor fermenter...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 12 2011-07-01 2009-07-01 true How do I demonstrate initial compliance with the emission limitations if I monitor fermenter exhaust? 63.2165 Section 63.2165 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE...

40 CFR 63.2165 - How do I demonstrate initial compliance with the emission limitations if I monitor fermenter...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 12 2010-07-01 2010-07-01 true How do I demonstrate initial compliance with the emission limitations if I monitor fermenter exhaust? 63.2165 Section 63.2165 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE...

The operable modeling of simultaneous saccharification and fermentation of ethanol production from cellulose.

PubMed

Shen, Jiacheng; Agblevor, Foster A

2010-03-01

An operable batch model of simultaneous saccharification and fermentation (SSF) for ethanol production from cellulose has been developed. The model includes four ordinary differential equations that describe the changes of cellobiose, glucose, yeast, and ethanol concentrations with respect to time. These equations were used to simulate the experimental data of the four main components in the SSF process of ethanol production from microcrystalline cellulose (Avicel PH101). The model parameters at 95% confidence intervals were determined by a MATLAB program based on the batch experimental data of the SSF. Both experimental data and model simulations showed that the cell growth was the rate-controlling step at the initial period in a series of reactions of cellulose to ethanol, and later, the conversion of cellulose to cellobiose controlled the process. The batch model was extended to the continuous and fed-batch operating models. For the continuous operation in the SSF, the ethanol productivities increased with increasing dilution rate, until a maximum value was attained, and rapidly decreased as the dilution rate approached the washout point. The model also predicted a relatively high ethanol mass for the fed-batch operation than the batch operation.

Three immobilized-cell columnar bioreactors for enhanced production of commodity chemicals

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

Davison, B.H.; Scott, C.D.; Kaufman, E.N.

1993-07-01

Immobilized-cell fluidized-bed bioreactors (FBRS) can be used with a variety of fermentations to increase production of fuels, solvents, organic acids, and other fermentation products. Part of the increased rates and yields are due to the immobilization of the biocatalyst at high concentrations. This FBR system with immobilized Zymomonas mobiles increased ethanol productivity more than tenfold with 99% conversion and near stoichiometric yields. FBRs also offer several additional modes of operation for simultaneous fermentation and separation to further increase production by removing the inhibitory products directly from the continuous fermentation. The production of lactic acid by immobilized Lactobacillus was augmented withmore » the addition and removal of solid adsorbent particles to the FBR. An immiscible organic extractant also was used to extract butanol from the acetone-butanol fermentation by Clostridium acetobutylicum. Demonstrations with these FBR systems have already shown definite advantages by improved overall product yields (decreasing feed costs) and by increased rates (decreasing capital and operating costs). Further demonstration and scale-up continue.« less

Three immobilized-cell columnar bioreactors for enhanced production of commodity chemicals

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

Davison, B.H.; Scott, C.D.; Kaufman, E.N.

1993-12-31

Immobilized-cell fluidized-bed bioreactors (FBRs) can be used with a variety of fermentations to increase production of fuels, solvents, organic acids, and other fermentation products. Part of the increased rates and yields are due to the immobilization of the biocatalyst at high concentrations. This FBR system with immobilized Zymomonas mobilis increased ethanol productivity more than tenfold with 99% conversion and near stoichiometric yields. FBRs also offer several additional modes of operation for simultaneous fermentation and separation to further increase production by removing the inhibitory products directly from the continuous fermentation. The production of lactic acid by immobilized Lactobacillus was augmented withmore » the addition and removal of solid adsorbent particles to the FBR. An immiscible organic extractant also was used to extract butanol from the acetone-butanol fermentation by Clostridium acetobutylicum. Demonstrations with these FBR systems have already shown definite advantages by improved overall product yields (decreasing feed costs) and by increased rates (decreasing capital and operating costs). Further demonstration and scale-up continue.« less

Functioned silver nanoparticle loaded activated carbon for the recovery of bioactive molecule from bacterial fermenter for its bactericidal activity

NASA Astrophysics Data System (ADS)

Arivizhivendhan, Villalan; Mahesh, Mannacharaju; Boopathy, Ramasamy; Karthikeyan, Sekar; Mary, Rathanasamy Regina; Sekaran, Ganesan

2018-01-01

A novel continuous production and extraction of bacterial bioactive prodigiosin (PG) from fermented using silver nanoparticle impregnated functioned activated carbon composite is proposed for cost-effective and ecofriendly microbial technique. Hence, in this investigation silver nanoparticle was impregnated onto functioned activated carbon ([AC]F) as a support matrix and to enable the separation of PG conjugated silver nanoparticle from the fermented medium. A laboratory scale experiment was carried out to evaluate the continuous production and recovery of PG using [AC@Ag]F. Ag nanoparticle impregnated [AC]F ([AC@Ag]F) characterized by FT-IR, XRD, TGA, DSC and SEM. Instrumental analyses confirmed that Ag nanoparticles significantly impregnated on AC through the functionalization of AC with diethanolamine and it enhances the binding capacity between AC and Ag. The various process parameters, such as contact time, pH, and mass of [AC@Ag]F, were statistically optimized for the recovery of PG using Response Surface Methodology (RSM). The maximum extraction of PG in [AC@Ag]F was found to be 16.2 ± 0.2 mg g-1, its twofold higher than [AC]F. Further, PG conjugated [AC@Ag]F and ([AC@Ag]F-PG) were checked for the growth inhibition of gram negative and gram positive bacteria without formation of biofilm upto 96 h. Hence, the developed matrix could be eco-friendly, viable and lower energy consumption step for separation of the bacterial bioactive PG from fermented broth. In additionally, [AC@Ag]F-PG was used as an antifouling matrix without formation of biofilm.

A novel one-stage cultivation/fermentation strategy for improved biogas production with microalgal biomass.

PubMed

Klassen, Viktor; Blifernez-Klassen, Olga; Hoekzema, Yoep; Mussgnug, Jan H; Kruse, Olaf

2015-12-10

The use of alga biomass for biogas generation has been studied for over fifty years but until today, several distinct features, like inefficient degradation and low C/N ratios, limit the applicability of algal biomass for biogas production in larger scale. In this work we investigated a novel, one-stage combined cultivation/fermentation strategy including inherently progressing nitrogen starvation conditions to generate improved microalgal biomass substrates. For this strategy, comparable low amounts of nitrogen fertilizers were applied during cultivation and no additional enzymatic, chemical or physical pretreatments had to be performed. The results of this study demonstrate that progressing nitrogen limitation leads to continuously increasing C/N ratios of the biomass up to levels of 24-26 for all three tested alga strains (Chlamydomonas reinhardtii, Parachlorella kessleri and Scenedesmus obliquus). Importantly, the degradation efficiency of the algal cells increased with progressing starvation, leading to strain-specific cell disintegration efficiencies of 35%-100% during the fermentation process. Nitrogen limitation treatment resulted in a 65% increase of biogas yields for C. reinhardtii biomass (max. 698±23mL biogas g(-1) VS) when compared to replete conditions. For P. kessleri and S. obliquus, yields increased by 94% and 106% (max. 706±39mL and 586±36mL biogas g(-1) VS, respectively). From these results we conclude that this novel one-stage cultivation strategy with inherent nitrogen limitation can be used as a pretreatment for microalgal biomass generation, in order to produce accessible substrates with optimized C/N ratios for the subsequent anaerobic fermentation process, thus increasing methane production and avoiding the risk of ammonia inhibition effects within the fermenter. Copyright © 2015 Elsevier B.V. All rights reserved.

Microbioreactors with microfluidic control and a user-friendly connection to the actuator hardware

NASA Astrophysics Data System (ADS)

Buchenauer, A.; Funke, M.; Büchs, J.; Mokwa, W.; Schnakenberg, U.

2009-07-01

In this study, an array of microbioreactors based on the format of 48-well microtiter plates (MTPs) is presented. The process parameters pH and biomass are monitored online using commercially available optical sensor technology. A microfluidic device dispenses acid or base individually into each well for controlling the pH of fermentations. Fluid volumes from 72 nL to 940 nL can be supplied with valve opening times between 10 ms and 200 ms. One microfluidic device is capable of supplying four wells from two reservoirs. Up to four microfluidic devices can be integrated on the area of a prototype MTP. The devices are fabricated in polydimethylsiloxane (PDMS) using soft lithographic techniques and utilize pneumatically actuated microvalves. During fermentations, the microbioreactor is clamped to an orbital shaker and a temporary pneumatic connection guides the externally controlled pressurized air to the microfluidic device. Finally, fermentations of Escherichia coli in the presence and absence of pH control are carried out in the microbioreactor system over 18 h. During the fermentation the pH of the cultures is continuously monitored by means of optodes. An ammonia solution or phosphoric acid is dispensed to adjust the pH if it differs from the set point of 7.2. In a controlled culture, the pH can be sustained within 7.0 to 7.3 while the pH in an uncontrolled culture ranges between 6.5 and 9.0. This microbioreactor demonstrates the possibility of pH-controlled fermentations in micro-scale. The process control and the user friendly connection to the actuation hardware provide an easy handling comparable to standard MTPs.

Dynamic modeling and analyses of simultaneous saccharification and fermentation process to produce bio-ethanol from rice straw.

PubMed

Ko, Jordon; Su, Wen-Jun; Chien, I-Lung; Chang, Der-Ming; Chou, Sheng-Hsin; Zhan, Rui-Yu

2010-02-01

The rice straw, an agricultural waste from Asians' main provision, was collected as feedstock to convert cellulose into ethanol through the enzymatic hydrolysis and followed by the fermentation process. When the two process steps are performed sequentially, it is referred to as separate hydrolysis and fermentation (SHF). The steps can also be performed simultaneously, i.e., simultaneous saccharification and fermentation (SSF). In this research, the kinetic model parameters of the cellulose saccharification process step using the rice straw as feedstock is obtained from real experimental data of cellulase hydrolysis. Furthermore, this model can be combined with a fermentation model at high glucose and ethanol concentrations to form a SSF model. The fermentation model is based on cybernetic approach from a paper in the literature with an extension of including both the glucose and ethanol inhibition terms to approach more to the actual plants. Dynamic effects of the operating variables in the enzymatic hydrolysis and the fermentation models will be analyzed. The operation of the SSF process will be compared to the SHF process. It is shown that the SSF process is better in reducing the processing time when the product (ethanol) concentration is high. The means to improve the productivity of the overall SSF process, by properly using aeration during the batch operation will also be discussed.

Saccharomyces cerevisiae strains for second-generation ethanol production: from academic exploration to industrial implementation.

PubMed

Jansen, Mickel L A; Bracher, Jasmine M; Papapetridis, Ioannis; Verhoeven, Maarten D; de Bruijn, Hans; de Waal, Paul P; van Maris, Antonius J A; Klaassen, Paul; Pronk, Jack T

2017-08-01

The recent start-up of several full-scale 'second generation' ethanol plants marks a major milestone in the development of Saccharomyces cerevisiae strains for fermentation of lignocellulosic hydrolysates of agricultural residues and energy crops. After a discussion of the challenges that these novel industrial contexts impose on yeast strains, this minireview describes key metabolic engineering strategies that have been developed to address these challenges. Additionally, it outlines how proof-of-concept studies, often developed in academic settings, can be used for the development of robust strain platforms that meet the requirements for industrial application. Fermentation performance of current engineered industrial S. cerevisiae strains is no longer a bottleneck in efforts to achieve the projected outputs of the first large-scale second-generation ethanol plants. Academic and industrial yeast research will continue to strengthen the economic value position of second-generation ethanol production by further improving fermentation kinetics, product yield and cellular robustness under process conditions. © FEMS 2017.

Waste activated sludge fermentation: effect of solids retention time and biomass concentration.

PubMed

Yuan, Q; Sparling, R; Oleszkiewicz, J A

2009-12-01

Laboratory scale, room temperature, semi-continuous reactors were set-up to investigate the effect of solids retention time (SRT, equal to HRT hydraulic retention time) and biomass concentration on generation of volatile fatty acids (VFA) from the non-methanogenic fermentation of waste activated sludge (WAS) originating from an enhanced biological phosphorus removal process. It was found that VFA yields increased with SRT. At the longest SRT (10d), improved biomass degradation resulted in the highest soluble to total COD ratio and the highest VFA yield from the influent COD (0.14g VFA-COD/g TCOD). It was also observed that under the same SRT, VFA yields increased when the biomass concentration decreased. At a 10d SRT the VFA yield increased by 46%, when the biomass concentration decreased from 13g/L to 4.8g/L. Relatively high nutrient release was observed during fermentation. The average phosphorus release was 17.3mg PO(4)-P/g TCOD and nitrogen release was 25.8mg NH(4)-N/g TCOD.

Saccharomyces cerevisiae strains for second-generation ethanol production: from academic exploration to industrial implementation

PubMed Central

Jansen, Mickel L. A.; Bracher, Jasmine M.; Papapetridis, Ioannis; Verhoeven, Maarten D.; de Bruijn, Hans; de Waal, Paul P.; van Maris, Antonius J. A.; Klaassen, Paul

2017-01-01

Abstract The recent start-up of several full-scale ‘second generation’ ethanol plants marks a major milestone in the development of Saccharomyces cerevisiae strains for fermentation of lignocellulosic hydrolysates of agricultural residues and energy crops. After a discussion of the challenges that these novel industrial contexts impose on yeast strains, this minireview describes key metabolic engineering strategies that have been developed to address these challenges. Additionally, it outlines how proof-of-concept studies, often developed in academic settings, can be used for the development of robust strain platforms that meet the requirements for industrial application. Fermentation performance of current engineered industrial S. cerevisiae strains is no longer a bottleneck in efforts to achieve the projected outputs of the first large-scale second-generation ethanol plants. Academic and industrial yeast research will continue to strengthen the economic value position of second-generation ethanol production by further improving fermentation kinetics, product yield and cellular robustness under process conditions. PMID:28899031

Pilot scale fermentation of Jerusalem artichoke tuber pulp mashes

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

Ziobro, G.C.; Williams, L.A.

1983-01-01

Processing and fermentation of Jerusalem artichoke (Helianthus tuberosus L.) tuber pulp mashes were successfully carried out at pilot scales of 60 gallons and 1000 gallons. Whole tubers were pulped mechanically into a thick mash and fermented, using commercially available Saccharomyces cerevisiae and selected strains of Kluyveromyces fragilis. EtOH fermentation yields ranging from 50-70% of theoretical maximum were obtained in 3-4 days. Several problems regarding the processing and direct fermentation of tuber pulp mashes are discussed.

Microbial Community Dynamics during Production of the Mexican Fermented Maize Dough Pozol

PubMed Central

ben Omar, Nabil; Ampe, Frédéric

2000-01-01

The dynamics of the microbial community responsible for the traditional fermentation of maize in the production of Mexican pozol was investigated by using a polyphasic approach combining (i) microbial enumerations with culture media, (ii) denaturing gradient gel electrophoresis (DGGE) fingerprinting of total community DNA with bacterial and eukaryotic primers and sequencing of partial 16S ribosomal DNA (rDNA) genes, (iii) quantification of rRNAs from dominant microbial taxa by using phylogenetic oligonucleotide probes, and (iv) analysis of sugars and fermentation products. A Streptococcus species dominated the fermentation and accounted for between 25 and 75% of the total flora throughout the process. Results also showed that the initial epiphytic aerobic microflora was replaced in the first 2 days by heterofermentative lactic acid bacteria (LAB), including a close relative of Lactobacillus fermentum, producing lactic acid and ethanol; this heterolactic flora was then progressively replaced by homofermentative LAB (mainly close relatives of L. plantarum, L. casei, and L. delbrueckii) which continued acidification of the maize dough. At the same time, a very diverse community of yeasts and fungi developed, mainly at the periphery of the dough. The analysis of the DGGE patterns obtained with bacterial and eukaryotic primers targeting the 16S and 18S rDNA genes clearly demonstrated that there was a major shift in the community structure after 24 h and that high biodiversity—according to the Shannon-Weaver index—was maintained throughout the process. These results proved that a relatively high number of species, at least six to eight, are needed to perform this traditional lactic acid fermentation. The presence of Bifidobacterium, Enterococcus, and enterobacteria suggests a fecal origin of some important pozol microorganisms. Overall, the results obtained with different culture-dependent or -independent techniques clearly confirmed the importance of developing a polyphasic approach to study the ecology of fermented foods. PMID:10966374

Procedure of brewing alcohol as a staple food: case study of the fermented cereal liquor "Parshot" as a staple food in Dirashe special woreda, southern Ethiopia.

PubMed

Sunano, Yui

2016-07-01

For most brews, alcohol fermentation and lactic fermentation take place simultaneously during the brewing process, and alcohol fermentation can progress smoothly because the propagation of various microorganisms is prevented by lactic fermentation. It is not necessary to cause lactic fermentation with a thing generated naturally and intentionally. The people living in the Dirashe area in southern Ethiopia drink three types of alcoholic beverages that are prepared from cereals. From these alcoholic beverages, parshot is prepared by the addition of plant leaves for lactic fermentation and nech chaka by adding cereal powder for lactic fermentation before alcohol fermentation. People living in the Dirashe area partake of parshot as part of their staple diet. The brewing process used for parshot and a food culture with alcoholic beverages as parts of the staple diet are rare worldwide. This article discusses the significance of using lactic fermentation before alcoholic fermentation and focuses on lactic fermentation in the brewing methods used for the three kinds of alcoholic beverages consumed in the Dirashe area. We initially observed the brewing process and obtained information about the process from the people in that area. Next, we determined the pH and analyzed the lactic acid (g/100 g) and ethanol (g/100 g) content during lactic fermentation of parshot and nech chaka; the ethyl acetate (mg/100 g) and volatile base nitrogen (mg/100 g) content during this period was also analyzed. In addition, we compared the ethanol (g/100 g) content of all three kinds of alcoholic beverages after completion of brewing. The results showed that it was possible to consume large quantities of these alcoholic beverages because of the use of lactic fermentation before alcoholic fermentation, which improved the safety and preservation characteristics of the beverages by preventing the propagation of various microorganisms, improving flavor, and controlling the alcohol level.

Time delay and noise explaining the behaviour of the cell growth in fermentation process

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

Ayuobi, Tawfiqullah; Rosli, Norhayati; Bahar, Arifah

2015-02-03

This paper proposes to investigate the interplay between time delay and external noise in explaining the behaviour of the microbial growth in batch fermentation process. Time delay and noise are modelled jointly via stochastic delay differential equations (SDDEs). The typical behaviour of cell concentration in batch fermentation process under this model is investigated. Milstein scheme is applied for solving this model numerically. Simulation results illustrate the effects of time delay and external noise in explaining the lag and stationary phases, respectively for the cell growth of fermentation process.

Time delay and noise explaining the behaviour of the cell growth in fermentation process

NASA Astrophysics Data System (ADS)

Ayuobi, Tawfiqullah; Rosli, Norhayati; Bahar, Arifah; Salleh, Madihah Md

2015-02-01

This paper proposes to investigate the interplay between time delay and external noise in explaining the behaviour of the microbial growth in batch fermentation process. Time delay and noise are modelled jointly via stochastic delay differential equations (SDDEs). The typical behaviour of cell concentration in batch fermentation process under this model is investigated. Milstein scheme is applied for solving this model numerically. Simulation results illustrate the effects of time delay and external noise in explaining the lag and stationary phases, respectively for the cell growth of fermentation process.

Wastewater recycling technology for fermentation in polyunsaturated fatty acid production.

PubMed

Song, Xiaojin; Ma, Zengxin; Tan, Yanzhen; Zhang, Huidan; Cui, Qiu

2017-07-01

To reduce fermentation-associated wastewater discharge and the cost of wastewater treatment, which further reduces the total cost of DHA and ARA production, this study first analyzed the composition of wastewater from Aurantiochytrium (DHA) and Mortierella alpina (ARA) fermentation, after which wastewater recycling technology for these fermentation processes was developed. No negative effects of DHA and ARA production were observed when the two fermentation wastewater methods were cross-recycled. DHA and ARA yields were significantly inhibited when the wastewater from the fermentation process was directly reused. In 5-L fed-batch fermentation experiments, using this cross-recycle technology, the DHA and ARA yields were 30.4 and 5.13gL -1 , respectively, with no significant changes (P>0.05) compared to the control group, and the water consumption was reduced by half compared to the traditional process. Therefore, this technology has great potential in industrial fermentation for polyunsaturated fatty acid production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Batch-batch stable microbial community in the traditional fermentation process of huyumei broad bean pastes.

PubMed

Zhu, Linjiang; Fan, Zihao; Kuai, Hui; Li, Qi

2017-09-01

During natural fermentation processes, a characteristic microbial community structure (MCS) is naturally formed, and it is interesting to know about its batch-batch stability. This issue was explored in a traditional semi-solid-state fermentation process of huyumei, a Chinese broad bean paste product. The results showed that this MCS mainly contained four aerobic Bacillus species (8 log CFU per g), including B. subtilis, B. amyloliquefaciens, B. methylotrophicus, and B. tequilensis, and the facultative anaerobe B. cereus with a low concentration (4 log CFU per g), besides a very small amount of the yeast Zygosaccharomyces rouxii (2 log CFU per g). The dynamic change of the MCS in the brine fermentation process showed that the abundance of dominant species varied within a small range, and in the beginning of process the growth of lactic acid bacteria was inhibited and Staphylococcus spp. lost its viability. Also, the MCS and its dynamic change were proved to be highly reproducible among seven batches of fermentation. Therefore, the MCS naturally and stably forms between different batches of the traditional semi-solid-state fermentation of huyumei. Revealing microbial community structure and its batch-batch stability is helpful for understanding the mechanisms of community formation and flavour production in a traditional fermentation. This issue in a traditional semi-solid-state fermentation of huyumei broad bean paste was firstly explored. This fermentation process was revealed to be dominated by a high concentration of four aerobic species of Bacillus, a low concentration of B. cereus and a small amount of Zygosaccharomyces rouxii. Lactic acid bacteria and Staphylococcus spp. lost its viability at the beginning of fermentation. Such the community structure was proved to be highly reproducible among seven batches. © 2017 The Society for Applied Microbiology.

Current progress on truffle submerged fermentation: a promising alternative to its fruiting bodies.

PubMed

Tang, Ya-Jie; Liu, Rui-Sang; Li, Hong-Mei

2015-03-01

Truffle (Tuber spp.), also known as "underground gold," is popular in various cuisines because of its unique and characteristic aroma. Currently, truffle fruiting bodies are mostly obtained from nature and semi-artificial cultivation. However, the former source is scarce, and the latter is time-consuming, usually taking 4 to 12 years before harvest of the fruiting body. The truffle submerged fermentation process was first developed in Tang's lab as an alternative to its fruiting bodies. To the best of our knowledge, most reports of truffle submerged fermentation come from Tang's group. This review examines the current state of the truffle submerged fermentation process. First, the strategy to optimize the truffle submerged fermentation process is summarized; the final conditions yielded not only the highest reported truffle biomass but also the highest production of extracellular and intracellular polysaccharides. Second, the comparison of metabolites produced by truffle fermentation and fruiting bodies is presented, and the former were superior to the latter. Third, metabolites (i.e., volatile organic compounds, equivalent umami concentration, and sterol) derived from truffle fermentation could be regulated by fermentation process optimization. These findings indicated that submerged fermentation of truffles can be used for commercial production of biomass and metabolites as a promising alternative to generating its fruiting bodies in bioreactor.

Yeasts in sustainable bioethanol production: A review.

PubMed

Mohd Azhar, Siti Hajar; Abdulla, Rahmath; Jambo, Siti Azmah; Marbawi, Hartinie; Gansau, Jualang Azlan; Mohd Faik, Ainol Azifa; Rodrigues, Kenneth Francis

2017-07-01

Bioethanol has been identified as the mostly used biofuel worldwide since it significantly contributes to the reduction of crude oil consumption and environmental pollution. It can be produced from various types of feedstocks such as sucrose, starch, lignocellulosic and algal biomass through fermentation process by microorganisms. Compared to other types of microoganisms, yeasts especially Saccharomyces cerevisiae is the common microbes employed in ethanol production due to its high ethanol productivity, high ethanol tolerance and ability of fermenting wide range of sugars. However, there are some challenges in yeast fermentation which inhibit ethanol production such as high temperature, high ethanol concentration and the ability to ferment pentose sugars. Various types of yeast strains have been used in fermentation for ethanol production including hybrid, recombinant and wild-type yeasts. Yeasts can directly ferment simple sugars into ethanol while other type of feedstocks must be converted to fermentable sugars before it can be fermented to ethanol. The common processes involves in ethanol production are pretreatment, hydrolysis and fermentation. Production of bioethanol during fermentation depends on several factors such as temperature, sugar concentration, pH, fermentation time, agitation rate, and inoculum size. The efficiency and productivity of ethanol can be enhanced by immobilizing the yeast cells. This review highlights the different types of yeast strains, fermentation process, factors affecting bioethanol production and immobilization of yeasts for better bioethanol production.

Composition and function of sourdough microbiota: From ecological theory to bread quality.

PubMed

Gänzle, Michael; Ripari, Valery

2016-12-19

Sourdough has traditionally been used as leavening agent in artisanal baking. The production of baked and steamed cereal products increasingly employs sourdough as baking improver to achieve improved bread quality, or to obtain "clean label" products. Sourdoughs are maintained in bakeries by continuous propagation; composition and metabolic activity of sourdough microbiota and their impact on bread quality are therefore shaped by processing parameters and fermentation substrates. The diversity of fermentation processes leads to diverse compositions of sourdough microbiota. This communication explores whether concepts in community assembly support an improved understanding of the microbial ecology of sourdough. Community assembly is determined by diversification, drift, dispersal, and selection. Evidence for diversification in sourdoughs is inconclusive. Drift has been shown to shape sourdough microbiota only in specific cases. Increasing knowledge on the primary habitat of sourdough lactobacilli indicates that dispersal (limitation) is an important determinant in sourdoughs that are propagated only for short periods of time. In contrast, selection of adapted organisms mainly determines the microbiota of sourdoughs that are propagated for a long time. Bacterial metabolic traits that determine competitiveness in sourdough fermentation, i.e. effective use of maltose, exopolysaccharide formation from sucrose, the use of electron acceptors by heterofermentative lactic acid bacteria, and acid resistance mediated by arginine and glutamine conversion, also determine bread quality. The concepts in community assembly thus provide a valuable tool to understand the influence of the technology of sourdough fermentation on microbial ecology and on bread quality. Copyright © 2016 Elsevier B.V. All rights reserved.

Feed component inhibition in ethanolic fermentation by Saccharomyces cerevisiae.

PubMed

Maiorella, B L; Blanch, H W; Wilke, C R

1984-10-01

Inhibition by secondary feed components can limit productivity and restrict process options for the production of ethanol by fermentation. New fermentation processes (such as vacuum or extractive fermentation), while selectively removing ethanol, can concentrate nonmetabolized feed components in the remaining broth. Stillage recycle to reduce stillage waste treatment results in the buildup of nonmetabolized feed components. Continuous culture experiments are presented establishing an inhibition order: CaCl(2), (NH(4))(2)xSO(4) > NaCl, NH(4)Cl > KH(2)PO(4) > xylose, MgCl(2) > MgSO(4) > KCl. Reduction of the water activity alone is not an adequate predictor of the variation in inhibitory concentration among the different components tested. As a general trend, specific ethanol productivity increases and cell production decreases as inhibitors are added at higher concentration. We postulate that these results can be interpreted in terms of an increase in energy requirements for cell maintenance under hypertonic (stressed) conditions. Ion and carbohydrate transport and specific toxic effects are reviewed as they relate to the postulated inhibition mechanism. Glycerol production increases under hypertonic conditions and glycerol is postulated to function as a nontoxic osmoregulator. Calcium was the most inhibitory component tested, causing an 80%decline in cell mass production at 0.23 mol Ca(2+)/L and calcium is present at substantial concentration in many carbohydrate sources. For a typical final cane molasses feed, stillage recycle must be limited to less than onethird of the feed rate; otherwise inhibitory effects will be observed.

Extractive fermentation of acetic acid

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

Busche, R.M.

1991-12-31

In this technoeconomic evaluation of the manufacture of acetic acid by fermentation, the use of the bacterium: Acetobacter suboxydans from the old vinegar process was compared with expected performance of the newer Clostridium thermoaceticum bacterium. Both systems were projected to operate as immobilized cells in a continuous, fluidized bed bioreactor, using solvent extraction to recover the product. Acetobacter metabolizes ethanol aerobically to produce acid at 100 g/L in a low pH medium. This ensures that the product is in the form of a concentrated extractable free acid, rather than as an unextractable salt. Unfortunately, yields from glucose by way ofmore » the ethanol fermentation are poor, but near the biological limits of the organisms involved. Conversely, C. thermoaceticum is a thermophilic anaerobe that operates at high fermentation rates on glucose at neutral pH to produce acetate salts directly in substantially quantitative yields. However, it is severely inhibited by product, which restricts concentration to a dilute 20 g/L. An improved Acetobacter system operating with recycled cells at 50 g/L appears capable of producing acid at $0.38/lb, as compared with a $0.29/lb price for synthetic acid. However, this system has only a limited margin for process improvement. The present Clostridium system cannot compete, since the required selling price would be $0.42/lb. However, if the organism could be adapted to tolerate higher product concentrations at acid pH, selling price could be reduced to $0.22/lb, or about 80% of the price of synthetic acid.« less

The Use of Lactic Acid Bacteria Starter Cultures during the Processing of Fermented Cereal-based Foods in West Africa: A Review.

PubMed

Soro-Yao, Amenan Anastasie; Brou, Kouakou; Amani, Georges; Thonart, Philippe; Djè, Koffi Marcelin

2014-12-01

Lactic acid bacteria (LAB) are the primary microorganisms used to ferment maize-, sorghum- or millet-based foods that are processed in West Africa. Fermentation contributes to desirable changes in taste, flavour, acidity, digestibility and texture in gruels (ogi, baca, dalaki), doughs (agidi, banku, komé) or steam-cooked granulated products (arraw, ciacry, dégué). Similar to other fermented cereal foods that are available in Africa, these products suffer from inconsistent quality. The use of LAB starter cultures during cereal dough fermentation is a subject of increasing interest in efforts to standardise this step and guaranty product uniformity. However, their use by small-scale processing units or small agro-food industrial enterprises is still limited. This review aims to illustrate and discuss major issues that influence the use of LAB starter cultures during the processing of fermented cereal foods in West Africa.

The Use of Lactic Acid Bacteria Starter Cultures during the Processing of Fermented Cereal-based Foods in West Africa: A Review

PubMed Central

Soro-Yao, Amenan Anastasie; Brou, Kouakou; Amani, Georges; Thonart, Philippe; Djè, Koffi Marcelin

2014-01-01

Lactic acid bacteria (LAB) are the primary microorganisms used to ferment maize-, sorghum- or millet-based foods that are processed in West Africa. Fermentation contributes to desirable changes in taste, flavour, acidity, digestibility and texture in gruels (ogi, baca, dalaki), doughs (agidi, banku, komé) or steam-cooked granulated products (arraw, ciacry, dégué). Similar to other fermented cereal foods that are available in Africa, these products suffer from inconsistent quality. The use of LAB starter cultures during cereal dough fermentation is a subject of increasing interest in efforts to standardise this step and guaranty product uniformity. However, their use by small-scale processing units or small agro-food industrial enterprises is still limited. This review aims to illustrate and discuss major issues that influence the use of LAB starter cultures during the processing of fermented cereal foods in West Africa. PMID:27073601

Analysis of problems with dry fermentation process for biogas production

NASA Astrophysics Data System (ADS)

Pilát, Peter; Patsch, Marek; Jandačka, Jozef

2012-04-01

The technology of dry anaerobic fermentation is still meeting with some scepticism, and therefore in most biogas plants are used wet fermentation technology. Fermentation process would be not complete without an optimal controlled condition: dry matter content, density, pH, and in particular the reaction temperature. If is distrust of dry fermentation eligible it was on the workplace of the Department of Power Engineering at University of Zilina built an experimental small-scale biogas station that allows analysis of optimal parameters of the dry anaerobic fermentation, in particular, however, affect the reaction temperature on yield and quality of biogas.

Phytochemical profile and antioxidant activity of caper berries (Capparis spinosa L.): Evaluation of the influence of the fermentation process.

PubMed

Jiménez-López, J; Ruiz-Medina, A; Ortega-Barrales, P; Llorent-Martínez, E J

2018-06-01

In this work, we report the phytochemical profile and antioxidant activity of caper berries (Capparis spinosa L.) before and after a fermentation process. The phytochemical profiles were evaluated by high-performance liquid chromatography with UV and electrospray ionization mass spectrometry detection (HPLC-DAD-ESI-MS n ). Twenty-one compounds were characterized, and seven of them quantified. The main component of non-fermented berries was glucocapparin, which was degraded upon the fermentation process. Most of the compounds were quercetin and kaempferol glycosides, epicatechin, and proanthocyanidins. The main differences observed upon the fermentation process were a decrease in epicatechin concentration, the hydrolysis of quercetin glycosides, and the degradation of glucosinolates. Total phenolic and flavonoid contents, as well as the antioxidant activities by the in vitro antioxidant assays DPPH and ABTS + , were determined, observing that the values were slightly higher after the fermentation process. Copyright © 2018 Elsevier Ltd. All rights reserved.

Single-cell protein from waste cellulose

NASA Technical Reports Server (NTRS)

Dunlap, C. E.; Callihan, C. D.

1973-01-01

The recycle, reuse, or reclamation of single cell protein from liquid and solid agricultural waste fibers by a fermentation process is reported. It is shown that cellulose comprises the bulk of the fibers at 50% to 55% of the dry weight of the refuse and that its biodegradability is of prime importance in the choice of a substrate. The application of sodium hydroxide followed by heat and pressure serves to de-polymerize and disrupt lignin structure while swelling the cellulose to increase water uptake and pore volume. Some of the lignin, hemi-celluloses, ash, and cellulose of the material is hydrolized and solubilized. Introduction of microorganisms to the substrate fibers mixed with nutrients produces continuous fermentation of cellulose for further protein extraction and purification.

Prospective and development of butanol as an advanced biofuel.

PubMed

Xue, Chuang; Zhao, Xin-Qing; Liu, Chen-Guang; Chen, Li-Jie; Bai, Feng-Wu

2013-12-01

Butanol has been acknowledged as an advanced biofuel, but its production through acetone-butanol-ethanol (ABE) fermentation by clostridia is still not economically competitive, due to low butanol yield and titer. In this article, update progress in butanol production is reviewed. Low price and sustainable feedstocks such as lignocellulosic residues and dedicated energy crops are needed for butanol production at large scale to save feedstock cost, but processes are more complicated, compared to those established for ABE fermentation from sugar- and starch-based feedstocks. While rational designs targeting individual genes, enzymes or pathways are effective for improving butanol yield, global and systems strategies are more reasonable for engineering strains with stress tolerance controlled by multigenes. Compared to solvent-producing clostridia, engineering heterologous species such as Escherichia coli and Saccharomyces cerevisiae with butanol pathway might be a solution for eliminating the formation of major byproducts acetone and ethanol so that butanol yield can be improved significantly. Although batch fermentation has been practiced for butanol production in industry, continuous operation is more productive for large scale production of butanol as a biofuel, but a single chemostat bioreactor cannot achieve this goal for the biphasic ABE fermentation, and tanks-in-series systems should be optimized for alternative feedstocks and new strains. Moreover, energy saving is limited for the distillation system, even total solvents in the fermentation broth are increased significantly, since solvents are distilled to ~40% by the beer stripper, and more than 95% water is removed with the stillage without phase change, even with conventional distillation systems, needless to say that advanced chemical engineering technologies can distil solvents up to ~90% with the beer stripper, and the multistage pressure columns can well balance energy consumption for solvent fraction. Indeed, an increase in butanol titer with ABE fermentation can significantly save energy consumption for medium sterilization and stillage treatment, since concentrated medium can be used, and consequently total mass flow with production systems can be reduced. As for various in situ butanol removal technologies, their energy efficiency, capital investment and contamination risk to the fermentation process need to be evaluated carefully. © 2013 Elsevier Inc. All rights reserved.

Multiobjective optimization and multivariable control of the beer fermentation process with the use of evolutionary algorithms.

PubMed

Andrés-Toro, B; Girón-Sierra, J M; Fernández-Blanco, P; López-Orozco, J A; Besada-Portas, E

2004-04-01

This paper describes empirical research on the model, optimization and supervisory control of beer fermentation. Conditions in the laboratory were made as similar as possible to brewery industry conditions. Since mathematical models that consider realistic industrial conditions were not available, a new mathematical model design involving industrial conditions was first developed. Batch fermentations are multiobjective dynamic processes that must be guided along optimal paths to obtain good results. The paper describes a direct way to apply a Pareto set approach with multiobjective evolutionary algorithms (MOEAs). Successful finding of optimal ways to drive these processes were reported. Once obtained, the mathematical fermentation model was used to optimize the fermentation process by using an intelligent control based on certain rules.

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.

Xylose fermentation efficiency and inhibitor tolerance of the recombinant industrial Saccharomyces cerevisiae strain NAPX37.

PubMed

Li, Yun-Cheng; Mitsumasu, Kanako; Gou, Zi-Xi; Gou, Min; Tang, Yue-Qin; Li, Guo-Ying; Wu, Xiao-Lei; Akamatsu, Takashi; Taguchi, Hisataka; Kida, Kenji

2016-02-01

Industrial yeast strains with good xylose fermentation ability and inhibitor tolerance are important for economical lignocellulosic bioethanol production. The flocculating industrial Saccharomyces cerevisiae strain NAPX37, harboring the xylose reductase-xylitol dehydrogenase (XR-XDH)-based xylose metabolic pathway, displayed efficient xylose fermentation during batch and continuous fermentation. During batch fermentation, the xylose consumption rates at the first 36 h were similar (1.37 g/L/h) when the initial xylose concentrations were 50 and 75 g/L, indicating that xylose fermentation was not inhibited even when the xylose concentration was as high as 75 g/L. The presence of glucose, at concentrations of up to 25 g/L, did not affect xylose consumption rate at the first 36 h. Strain NAPX37 showed stable xylose fermentation capacity during continuous ethanol fermentation using xylose as the sole sugar, for almost 1 year. Fermentation remained stable at a dilution rate of 0.05/h, even though the xylose concentration in the feed was as high as 100 g/L. Aeration rate, xylose concentration, and MgSO4 concentration were found to affect xylose consumption and ethanol yield. When the xylose concentration in the feed was 75 g/L, a high xylose consumption rate of 6.62 g/L/h and an ethanol yield of 0.394 were achieved under an aeration rate of 0.1 vvm, dilution rate of 0.1/h, and 5 mM MgSO4. In addition, strain NAPX37 exhibited good tolerance to inhibitors such as weak acids, furans, and phenolics during xylose fermentation. These findings indicate that strain NAPX37 is a promising candidate for application in the industrial production of lignocellulosic bioethanol.

JPRS Report, Science & Technology, Europe

DTIC Science & Technology

1992-02-06

also sunflower and corn oil); bioethanol is produced by fermenting sugars extracted from sugar beets and grains. Regulations limit its share of...Metal Complexes"] [Text] Frankfurt, 16 Oct—The fermentation technology research team of the University of Bielefeld’s School of Engineering is...Frequency of Continuous Operation in Fermentation and Product Recovery" first two para- graphs are VDI NACHRICHTEN introduction] [Text

40 CFR 439.11 - Special definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... STANDARDS PHARMACEUTICAL MANUFACTURING POINT SOURCE CATEGORY Fermentation Products § 439.11 Special definitions. For the purpose of this subpart: (a) Fermentation means process operations that utilize a... means pharmaceutical products derived from fermentation processes. [68 FR 12271, Mar. 13, 2003] ...

40 CFR 439.11 - Special definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... STANDARDS PHARMACEUTICAL MANUFACTURING POINT SOURCE CATEGORY Fermentation Products § 439.11 Special definitions. For the purpose of this subpart: (a) Fermentation means process operations that utilize a... means pharmaceutical products derived from fermentation processes. [68 FR 12271, Mar. 13, 2003] ...

Cucumber fermentation

USDA-ARS?s Scientific Manuscript database

Humans have consumed fermented cucumber products since before the dawn of civilization. Although cucumber fermentation remains largely a traditional process, it has proven to be a consistently safe process by which raw cucumbers are transformed into high quality pickles that have a long shelf-life ...

40 CFR 180.522 - Fumigants for processed grains used in production of fermented malt beverage; tolerances for...

Code of Federal Regulations, 2010 CFR

2010-07-01

... production of fermented malt beverage; tolerances for residues. 180.522 Section 180.522 Protection of... PESTICIDE CHEMICAL RESIDUES IN FOOD Specific Tolerances § 180.522 Fumigants for processed grains used in production of fermented malt beverage; tolerances for residues. (a) General. Fumigants for processed grain...

Kinetics model development of cocoa bean fermentation

NASA Astrophysics Data System (ADS)

Kresnowati, M. T. A. P.; Gunawan, Agus Yodi; Muliyadini, Winny

2015-12-01

Although Indonesia is one of the biggest cocoa beans producers in the world, Indonesian cocoa beans are oftenly of low quality and thereby frequently priced low in the world market. In order to improve the quality, adequate post-harvest cocoa processing techniques are required. Fermentation is the vital stage in series of cocoa beans post harvest processing which could improve the quality of cocoa beans, in particular taste, aroma, and colours. During the fermentation process, combination of microbes grow producing metabolites that serve as the precursors for cocoa beans flavour. Microbial composition and thereby their activities will affect the fermentation performance and influence the properties of cocoa beans. The correlation could be reviewed using a kinetic model that includes unstructured microbial growth, substrate utilization and metabolic product formation. The developed kinetic model could be further used to design cocoa bean fermentation process to meet the expected quality. Further the development of kinetic model of cocoa bean fermentation also serve as a good case study of mixed culture solid state fermentation, that has rarely been studied. This paper presents the development of a kinetic model for solid-state cocoa beans fermentation using an empirical approach. Series of lab scale cocoa bean fermentations, either natural fermentations without starter addition or fermentations with mixed yeast and lactic acid bacteria starter addition, were used for model parameters estimation. The results showed that cocoa beans fermentation can be modelled mathematically and the best model included substrate utilization, microbial growth, metabolites production and its transport. Although the developed model still can not explain the dynamics in microbial population, this model can sufficiently explained the observed changes in sugar concentration as well as metabolic products in the cocoa bean pulp.

An Innovative Optical Sensor for the Online Monitoring and Control of Biomass Concentration in a Membrane Bioreactor System for Lactic Acid Production

PubMed Central

Fan, Rong; Ebrahimi, Mehrdad; Quitmann, Hendrich; Aden, Matthias; Czermak, Peter

2016-01-01

Accurate real-time process control is necessary to increase process efficiency, and optical sensors offer a competitive solution because they provide diverse system information in a noninvasive manner. We used an innovative scattered light sensor for the online monitoring of biomass during lactic acid production in a membrane bioreactor system because biomass determines productivity in this type of process. The upper limit of the measurement range in fermentation broth containing Bacillus coagulans was ~2.2 g·L−1. The specific cell growth rate (µ) during the exponential phase was calculated using data representing the linear range (cell density ≤ 0.5 g·L−1). The results were consistently and reproducibly more accurate than offline measurements of optical density and cell dry weight, because more data were gathered in real-time over a shorter duration. Furthermore, µmax was measured under different filtration conditions (transmembrane pressure 0.3–1.2 bar, crossflow velocity 0.5–1.5 m·s−1), showing that energy input had no significant impact on cell growth. Cell density was monitored using the sensor during filtration and was maintained at a constant level by feeding with glucose according to the fermentation kinetics. Our novel sensor is therefore suitable for integration into control strategies for continuous fermentation in membrane bioreactor systems. PMID:27007380

Production of bio ethanol from waste potatoes

NASA Astrophysics Data System (ADS)

Jaber Noufal, Mohamad; Li, Baizhan; Maalla, Zena Ali

2017-03-01

In this research, production of ethanol from waste potatoes fermentation was studied using Saccharomyces cerevisiae. Potato Flour prepared from potato tubers after cooking and drying at 85°C. A homogenous slurry of potato flour prepared in water at solid-liquid ratio 1:10. Liquefaction of potato starch slurry was done with α-amylase at 80°C for 40 min followed by saccharification process which was done with glucoamylase at 65°C for two hr. Fermentation of hydrolysate with Saccharomyces cerevisiae at 35°C for two days resulted in the production of 33 g/l ethanol. The following parameters have been analysed: temperature, time of fermentation and pH. It found that Saccharification process is affected by enzyme Amylase 300 concentration and concentration of 1000μl/100ml gives the efficient effect of the process. The best temperature for fermentation process was found to be about 35°C. Also, it noticed that ethanol production increased as a time of fermentation increased but after 48 hr further growth in fermentation time did not have an appreciable effect. Finally, the optimal value of pH for fermentation process was about 5 to 6.

Fermentative hydrogen production from molasses wastewater in a continuous mixed immobilized sludge reactor.

PubMed

Han, Wei; Wang, Bing; Zhou, Yan; Wang, De-Xin; Wang, Yan; Yue, Li-Ran; Li, Yong-Feng; Ren, Nan-Qi

2012-04-01

A novel continuous mixed immobilized sludge reactor (CMISR) containing activated carbon as support carrier was used for fermentative hydrogen production from molasses wastewater. When the CMISR system operated at the conditions of influent COD of 2000-6000mg/L, hydraulic retention time (HRT) of 6h and temperature of 35°C, stable ethanol type fermentation was formed after 40days operation. The H(2) content in biogas and chemical oxygen demand (COD) removal were estimated to be 46.6% and 13%, respectively. The effects of organic loading rates (OLRs) on the CMISR hydrogen production system were also investigated. It was found that the maximum hydrogen production rate of 12.51mmol/hL was obtained at OLR of 32kg/m(3)d and the maximum hydrogen yield by substrate consumed of 130.57mmol/mol happened at OLR of 16kg/m(3)d. Therefore, the continuous mixed immobilized sludge reactor (CMISR) could be a promising immobilized system for fermentative hydrogen production. Copyright © 2012 Elsevier Ltd. All rights reserved.

Monitoring and Evaluation of Alcoholic Fermentation Processes Using a Chemocapacitor Sensor Array

PubMed Central

Oikonomou, Petros; Raptis, Ioannis; Sanopoulou, Merope

2014-01-01

The alcoholic fermentation of Savatiano must variety was initiated under laboratory conditions and monitored daily with a gas sensor array without any pre-treatment steps. The sensor array consisted of eight interdigitated chemocapacitors (IDCs) coated with specific polymers. Two batches of fermented must were tested and also subjected daily to standard chemical analysis. The chemical composition of the two fermenting musts differed from day one of laboratory monitoring (due to different storage conditions of the musts) and due to a deliberate increase of the acetic acid content of one of the musts, during the course of the process, in an effort to spoil the fermenting medium. Sensor array responses to the headspace of the fermenting medium were compared with those obtained either for pure or contaminated samples with controlled concentrations of standard ethanol solutions of impurities. Results of data processing with Principal Component Analysis (PCA), demonstrate that this sensing system could discriminate between a normal and a potential spoiled grape must fermentation process, so this gas sensing system could be potentially applied during wine production as an auxiliary qualitative control instrument. PMID:25184490

Effect of mixing during fermentation in yogurt manufacturing.

PubMed

Aguirre-Ezkauriatza, E J; Galarza-González, M G; Uribe-Bujanda, A I; Ríos-Licea, M; López-Pacheco, F; Hernández-Brenes, C M; Alvarez, M M

2008-12-01

In traditional yogurt manufacturing, the yogurt is not agitated during fermentation. However, stirring could be beneficial, particularly for improving heat and mass transport across the fermentation tank. In this contribution, we studied the effect of low-speed agitation during fermentation on process time, acidity profile, and microbial dynamics during yogurt fermentation in 2 laboratory-scale fermenters (3 and 5 L) with different heat-transfer characteristics. Lactobacillus bulgaricus and Streptococcus thermophilus were used as fermenting bacteria. Curves of pH, lactic acid concentration, lactose concentration, and bacterial population profiles during fermentation are presented for static and low-agitation conditions during fermentation. At low-inoculum conditions, agitation reduced the processing time by shortening the lag phase. However, mixing did not modify the duration or the shape of the pH profiles during the exponential phase. In fermentors with poor heat-transfer characteristics, important differences in microbial dynamics were observed between the agitated and nonagitated fermentation experiments; that is, agitation significantly increased the observable specific growth rate and the final microbial count of L. bulgaricus.

Evolved strains of Scheffersomyces stipitis achieving high ethanol productivity on acid- and base-pretreated biomass hydrolyzate at high solids loading

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

Slininger, Patricia J.; Shea-Andersh, Maureen A.; Thompson, Stephanie R.

Lignocellulosic biomass is an abundant, renewable feedstock useful for the production of fuel-grade ethanol via the processing steps of pretreatment, enzyme hydrolysis, and microbial fermentation. Traditional industrial yeasts do not ferment xylose and are not able to grow, survive, or ferment in concentrated hydrolyzates that contain enough sugar to support economical ethanol recovery since they are laden with toxic byproducts generated during pretreatment. Repetitive culturing in two types of concentrated hydrolyzates was applied along with ethanol challenged xylose-fed continuous culture to force targeted evolution of the native pentose fermenting yeast Scheffersomyces (Pichia) stipitis strain NRRL Y-7124 maintained in the ARSmore » Culture Collection, Peoria, IL. Isolates collected from various enriched populations were screened and ranked based on relative xylose uptake rate and ethanol yield. Ranking on hydrolyzates with and without nutritional supplementation was used to identify those isolates with best performance across diverse conditions. Robust S. stipitis strains adapted to perform very well in enzyme hydrolyzates of high solids loading ammonia fiber expansion-pretreated corn stover (18% weight per volume solids) and dilute sulfuric acid-pretreated switchgrass (20% w/v solids) were obtained. Improved features include reduced initial lag phase preceding growth, significantly enhanced fermentation rates, improved ethanol tolerance and yield, reduced diauxic lag during glucose-xylose transition, and ability to accumulate >40 g/L ethanol in <167 h when fermenting hydrolyzate at low initial cell density of 0.5 absorbance units and pH 5 to 6.« less

Evolved strains of Scheffersomyces stipitis achieving high ethanol productivity on acid- and base-pretreated biomass hydrolyzate at high solids loading

DOE PAGES

Slininger, Patricia J.; Shea-Andersh, Maureen A.; Thompson, Stephanie R.; ...

2015-04-09

Lignocellulosic biomass is an abundant, renewable feedstock useful for the production of fuel-grade ethanol via the processing steps of pretreatment, enzyme hydrolysis, and microbial fermentation. Traditional industrial yeasts do not ferment xylose and are not able to grow, survive, or ferment in concentrated hydrolyzates that contain enough sugar to support economical ethanol recovery since they are laden with toxic byproducts generated during pretreatment. Repetitive culturing in two types of concentrated hydrolyzates was applied along with ethanol challenged xylose-fed continuous culture to force targeted evolution of the native pentose fermenting yeast Scheffersomyces (Pichia) stipitis strain NRRL Y-7124 maintained in the ARSmore » Culture Collection, Peoria, IL. Isolates collected from various enriched populations were screened and ranked based on relative xylose uptake rate and ethanol yield. Ranking on hydrolyzates with and without nutritional supplementation was used to identify those isolates with best performance across diverse conditions. Robust S. stipitis strains adapted to perform very well in enzyme hydrolyzates of high solids loading ammonia fiber expansion-pretreated corn stover (18% weight per volume solids) and dilute sulfuric acid-pretreated switchgrass (20% w/v solids) were obtained. Improved features include reduced initial lag phase preceding growth, significantly enhanced fermentation rates, improved ethanol tolerance and yield, reduced diauxic lag during glucose-xylose transition, and ability to accumulate >40 g/L ethanol in <167 h when fermenting hydrolyzate at low initial cell density of 0.5 absorbance units and pH 5 to 6.« less

Dominance of Saccharomyces cerevisiae in alcoholic fermentation processes: role of physiological fitness and microbial interactions.

PubMed

Albergaria, Helena; Arneborg, Nils

2016-03-01

Winemaking, brewing and baking are some of the oldest biotechnological processes. In all of them, alcoholic fermentation is the main biotransformation and Saccharomyces cerevisiae the primary microorganism. Although a wide variety of microbial species may participate in alcoholic fermentation and contribute to the sensory properties of end-products, the yeast S. cerevisiae invariably dominates the final stages of fermentation. The ability of S. cerevisiae to outcompete other microbial species during alcoholic fermentation processes, such as winemaking, has traditionally been ascribed to its high fermentative power and capacity to withstand the harsh environmental conditions, i.e. high levels of ethanol and organic acids, low pH values, scarce oxygen availability and depletion of certain nutrients. However, in recent years, several studies have raised evidence that S. cerevisiae, beyond its remarkable fitness for alcoholic fermentation, also uses defensive strategies mediated by different mechanisms, such as cell-to-cell contact and secretion of antimicrobial peptides, to combat other microorganisms. In this paper, we review the main physiological features underlying the special aptitude of S. cerevisiae for alcoholic fermentation and discuss the role of microbial interactions in its dominance during alcoholic fermentation, as well as its relevance for winemaking.

Comparison of solid-state and submerged-state fermentation for the bioprocessing of switchgrass to ethanol and acetate by Clostridium phytofermentans.

PubMed

Jain, Abhiney; Morlok, Charles K; Henson, J Michael

2013-01-01

The conversion of sustainable energy crops using microbiological fermentation to biofuels and bioproducts typically uses submerged-state processes. Alternatively, solid-state fermentation processes have several advantages when compared to the typical submerged-state processes. This study compares the use of solid-state versus submerged-state fermentation using the mesophilic anaerobic bacterium Clostridium phytofermentans in the conversion of switchgrass to the end products of ethanol, acetate, and hydrogen. A shift in the ratio of metabolic products towards more acetate and hydrogen production than ethanol production was observed when C. phytofermentans was grown under solid-state conditions as compared to submerged-state conditions. Results indicated that the end product concentrations (in millimolar) obtained using solid-state fermentation were higher than using submerged-state fermentation. In contrast, the total fermentation products (in weight of product per weight of carbohydrates consumed) and switchgrass conversion were higher for submerged-state fermentation. The conversion of xylan was greater than glucan conversion under both fermentation conditions. An initial pH of 7 and moisture content of 80 % resulted in maximum end products formation. Scanning electron microscopy study showed the presence of biofilm formed by C. phytofermentans growing on switchgrass under submerged-state fermentation whereas bacterial cells attached to surface and no apparent biofilm was observed when grown under solid-state fermentation. To our knowledge, this is the first study reporting consolidated bioprocessing of a lignocellulosic substrate by a mesophilic anaerobic bacterium under solid-state fermentation conditions.

78 FR 12591 - Amendment to the Standards of Identity for Distilled Spirits

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-25

... ``Cacha[ccedil]a'' any spirits that use corn or corn syrup in the fermentation process. Some product... have been manufactured using a small quantity of corn or corn syrup in the fermentation process. Since... standard for Cacha[ccedil]a would not allow for the use of corn or corn syrup in the fermentation process...

Rich nutrition from the poorest - cereal fermentations in Africa and Asia.

PubMed

Nout, M J Rob

2009-10-01

Cereal fermentations in Africa and Asia involve mainly the processing of maize, rice, sorghum and the millets. Lactic acid bacteria (Lactobacillus, Pediococcus), Enterobacter spp., yeasts (Candida, Debaryomyces, Endomycopsis, Hansenula, Pichia, Saccharomyces and Trichosporon spp.) and filamentous fungi (Amylomyces, Aspergillus, Mucor, and Rhizopus spp.) contribute to desirable modifications of taste, flavour, acidity, digestibility, and texture in non-alcoholic beverages (e.g., uji, and ben-saalga), porridges (e.g., mawè) and cooked gels (e.g., kenkey, idli, and mifen). In addition, alcoholic beverages (beers such as tchoukoutou and jnard; and spirits e.g. jiu) are obtained using malt, or using amylolytic mixed microbial starter cultures as generators of fermentable substrates. Wet processing, marketing of multi-purpose intermediate products, co-fermentation for texture and nutrition, and mixed culture fermentations as practiced in indigenous fermentation processes are of interest for industrial innovation and for better control of natural mixed culture fermentation systems. On the other hand, the nutritional properties of traditional cereal fermented products can be enhanced by increasing their nutrient and energy density, as well as by increasing their mineral status by combining mineral fortification and dephytinization.

A next generation, pilot-scale continuous sterilization system for fermentation media

PubMed Central

Lester, M.; Brix, T.; Wong, D.; Nuechterlein, J.

2006-01-01

A new continuous sterilization system was designed, constructed, started up, and qualified for media sterilization for secondary metabolite cultivations, bioconversions, and enzyme production. An existing Honeywell Total Distributed Control 3000-based control system was extended using redundant High performance Process Manager controllers for 98 I/O (input/output) points. This new equipment was retrofitted into an industrial research fermentation pilot plant, designed and constructed in the early 1980s. Design strategies of this new continuous sterilizer system and the expanded control system are described and compared with the literature (including dairy and bio-waste inactivation applications) and the weaknesses of the prior installation for expected effectiveness. In addition, the reasoning behind selection of some of these improved features has been incorporated. Examples of enhancements adopted include sanitary heat exchanger (HEX) design, incorporation of a “flash” cooling HEX, on-line calculation of Fo and Ro, and use of field I/O modules located near the vessel to permit low-cost addition of new instrumentation. Sterilizer performance also was characterized over the expected range of operating conditions. Differences between design and observed temperature, pressure, and other profiles were quantified and investigated. PMID:16496186

Consumer Acceptability of Cucumber Pickles Produced by Fermentation in Calcium Chloride Brine for Reduced Environmental Impact.

PubMed

Wilson, Emily M; Johanningsmeier, Suzanne D; Osborne, Jason A

2015-06-01

Fermentation of cucumbers in calcium chloride (CaCl2 ) brine has been proposed as an alternative process to reduce the environmental impact of traditional, high salt fermentations. The objective of this research was to determine whether consumer acceptability of pickle products would be impacted by fermentation and storage of cucumbers in CaCl2 brine. Cucumbers were fermented and stored with 0.1M CaCl2 or 1M sodium chloride (NaCl) in open-air, 3000 gal tanks at a commercial facility and processed into hamburger dill chips containing 0.38M NaCl. Cucumbers fermented in CaCl2 required additional desalting to reduce CaCl2 concentrations to that of current products. Consumers (n = 101) showed no significant preference for pickles from different fermentation treatments, whether stored for 2 mo (P = 0.75) or 8 mo (P = 0.68) prior to processing. In contrast, NaCl fermented pickles were preferred over CaCl2 fermented pickles stored for 10 mo and desalted only once (P < 0.01). A series of preference tests indicated that the taste of CaCl2 was not the factor affecting consumer preference, and the 50% detection threshold of CaCl2 in dill pickle chips was found to be 61.8 ± 7.6 mM, indicating that processors could potentially use CaCl2 fermentations with a single desalting step. Consumer liking of flavor (n = 73) was not influenced by fermentation in CaCl2 or by 23 or 35 mM CaCl2 in finished products (P > 0.05), but variability in texture decreased consumer liking (P < 0.05). Although promising, individual fermentation variability and texture quality of CaCl2 fermented products should be further evaluated prior to broad implementation of this process. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Daniel J. Schell | NREL

Science.gov Websites

processing High solids biomass conversion Fermentation process development Separation processes Techno ; Bioresour. Technol. (2010) "An economic comparison of different fermentation configurations to convert

Black rhinoceros (Diceros bicornis) and domestic horse (Equus caballus) hindgut microflora demonstrate similar fermentation responses to grape seed extract supplementation in vitro.

PubMed

Huntley, N F; Naumann, H D; Kenny, A L; Kerley, M S

2017-10-01

The domestic horse is used as a nutritional model for rhinoceros maintained under human care. The validity of this model for browsing rhinoceros has been questioned due to high prevalence of iron overload disorder (IOD) in captive black rhinoceros (Diceros bicornis), which is associated with high morbidity and mortality. Iron chelators, such as tannins, are under investigation as dietary supplements to ameliorate or prevent IOD in prone species. Polyphenolic compounds variably affect microbial fermentation, so the first objective of this experiment was to evaluate the effects of grape seed extract (GSE; a concentrated source of condensed tannins; CT) on black rhinoceros hindgut fermentation. Equine nutrition knowledge is used to assess supplements for rhinoceros; therefore, the second objective was to evaluate the domestic horse model for black rhinoceros fermentation and compare fermentation responses to GSE using a continuous single-flow in vitro culture system. Two replicated continuous culture experiments were conducted using horse and black rhinoceros faeces as inoculum sources comparing four diets with increasing GSE inclusion (0.0%, 1.3%, 2.7% and 4.0% of diet dry matter). Diet and GSE polyphenolic compositions were determined, and sodium sulphite effect on neutral detergent fibre extraction of CT-containing forages was tested. Increasing GSE inclusion stimulated microbial growth and fermentation, and proportionally increased diet CT concentration and iron-binding capacity. Horse and black rhinoceros hindgut microflora nutrient digestibility and fermentation responses to GSE did not differ, and results supported equine fermentation as an adequate model for microbial fermentation in the black rhinoceros. Interpretation of these results is limited to hindgut fermentation and further research is needed to compare foregut digestibility and nutrient absorption between these two species. Supplementation of GSE in black rhinoceros diets up to 4% is unlikely to adversely affect hindgut nutrient digestibility or microbial viability and fermentation. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

Effect of fermentation parameters on bio-alcohols production from glycerol using immobilized Clostridium pasteurianum: an optimization study.

PubMed

Khanna, Swati; Goyal, Arun; Moholkar, Vijayanand S

2013-01-01

This article addresses the issue of effect of fermentation parameters for conversion of glycerol (in both pure and crude form) into three value-added products, namely, ethanol, butanol, and 1,3-propanediol (1,3-PDO), by immobilized Clostridium pasteurianum and thereby addresses the statistical optimization of this process. The analysis of effect of different process parameters such as agitation rate, fermentation temperature, medium pH, and initial glycerol concentration indicated that medium pH was the most critical factor for total alcohols production in case of pure glycerol as fermentation substrate. On the other hand, initial glycerol concentration was the most significant factor for fermentation with crude glycerol. An interesting observation was that the optimized set of fermentation parameters was found to be independent of the type of glycerol (either pure or crude) used. At optimum conditions of agitation rate (200 rpm), initial glycerol concentration (25 g/L), fermentation temperature (30°C), and medium pH (7.0), the total alcohols production was almost equal in anaerobic shake flasks and 2-L bioreactor. This essentially means that at optimum process parameters, the scale of operation does not affect the output of the process. The immobilized cells could be reused for multiple cycles for both pure and crude glycerol fermentation.

Kinetic studies on batch cultivation of Trichoderma reesei and application to enhance cellulase production by fed-batch fermentation.

PubMed

Ma, Lijuan; Li, Chen; Yang, Zhenhua; Jia, Wendi; Zhang, Dongyuan; Chen, Shulin

2013-07-20

Reducing the production cost of cellulase as the key enzyme for cellulose hydrolysis to fermentable sugars remains a major challenge for biofuel production. Because of the complexity of cellulase production, kinetic modeling and mass balance calculation can be used as effective tools for process design and optimization. In this study, kinetic models for cell growth, substrate consumption and cellulase production in batch fermentation were developed, and then applied in fed-batch fermentation to enhance cellulase production. Inhibition effect of substrate was considered and a modified Luedeking-Piret model was developed for cellulase production and substrate consumption according to the growth characteristics of Trichoderma reesei. The model predictions fit well with the experimental data. Simulation results showed that higher initial substrate concentration led to decrease of cellulase production rate. Mass balance and kinetic simulation results were applied to determine the feeding strategy. Cellulase production and its corresponding productivity increased by 82.13% after employing the proper feeding strategy in fed-batch fermentation. This method combining mathematics and chemometrics by kinetic modeling and mass balance can not only improve cellulase fermentation process, but also help to better understand the cellulase fermentation process. The model development can also provide insight to other similar fermentation processes. Copyright © 2013 Elsevier B.V. All rights reserved.

Production of bio-fuel ethanol from distilled grain waste eluted from Chinese spirit making process.

PubMed

Tan, Li; Sun, Zhaoyong; Zhang, Wenxue; Tang, Yueqin; Morimura, Shigeru; Kida, Kenji

2014-10-01

Distilled grain waste eluted from Chinese spirit making is rich in carbohydrates, and could potentially serve as feedstock for the production of bio-fuel ethanol. Our study evaluated two types of saccharification methods that convert distilled grain waste to monosaccharides: enzymatic saccharification and concentrated H2SO4 saccharification. Results showed that enzymatic saccharification performed unsatisfactorily because of inefficient removal of lignin during pretreatment. Concentrated H2SO4 saccharification led to a total sugar recovery efficiency of 79.0 %, and to considerably higher sugar concentrations than enzymatic saccharification. The process of ethanol production from distilled grain waste based on concentrated H2SO4 saccharification was then studied. The process mainly consisted of concentrated H2SO4 saccharification, solid-liquid separation, decoloration, sugar-acid separation, oligosaccharide hydrolysis, and continuous ethanol fermentation. An improved simulated moving bed system was employed to separate sugars from acid after concentrated H2SO4 saccharification, by which 95.8 % of glucose and 85.8 % of xylose went into the sugar-rich fraction, while 83.3 % of H2SO4 went into the acid-rich fraction. A flocculating yeast strain, Saccharomyces cerevisiae KF-7, was used for continuous ethanol fermentation, which produced an ethanol yield of 91.9-98.9 %, based on glucose concentration.

21 CFR 173.160 - Candida guilliermondii.

Code of Federal Regulations, 2010 CFR

2010-04-01

... guilliermondii may be safely used as the organism for fermentation production of citric acid in accordance with... guilliermondii and its concomitant metabolites produced during the fermentation process. (b)(1) The nonpathogenic... pure culture in the fermentation process for the production of citric acid using an acceptable aqueous...

Ethanol fermentation characteristics of recycled water by Saccharomyces cerevisiae in an integrated ethanol-methane fermentation process.

PubMed

Yang, Xinchao; Wang, Ke; Wang, Huijun; Zhang, Jianhua; Mao, Zhonggui

2016-11-01

An process of integrated ethanol-methane fermentation with improved economics has been studied extensively in recent years, where the process water used for a subsequent fermentation of carbohydrate biomass is recycled. This paper presents a systematic study of the ethanol fermentation characteristics of recycled process water. Compared with tap water, fermentation time was shortened by 40% when mixed water was employed. However, while the maximal ethanol production rate increased from 1.07g/L/h to 2.01g/L/h, ethanol production was not enhanced. Cell number rose from 0.6×10(8) per mL in tap water to 1.6×10(8) per mL in mixed water but although biomass increased, cell morphology was not affected. Furthermore, the use of mixed water increased the glycerol yield but decreased that of acetic acid, and the final pH with mixed water was higher than when using tap water. Copyright © 2016 Elsevier Ltd. All rights reserved.

[GSH fermentation process modeling using entropy-criterion based RBF neural network model].

PubMed

Tan, Zuoping; Wang, Shitong; Deng, Zhaohong; Du, Guocheng

2008-05-01

The prediction accuracy and generalization of GSH fermentation process modeling are often deteriorated by noise existing in the corresponding experimental data. In order to avoid this problem, we present a novel RBF neural network modeling approach based on entropy criterion. It considers the whole distribution structure of the training data set in the parameter learning process compared with the traditional MSE-criterion based parameter learning, and thus effectively avoids the weak generalization and over-learning. Then the proposed approach is applied to the GSH fermentation process modeling. Our results demonstrate that this proposed method has better prediction accuracy, generalization and robustness such that it offers a potential application merit for the GSH fermentation process modeling.

Evaluation of options for harvest of a recombinant E. Coli fermentation producing a domain antibody using ultra scale‐down techniques and pilot‐scale verification

PubMed Central

Voulgaris, Ioannis; Chatel, Alex; Finka, Gary; Uden, Mark

2016-01-01

Ultra scale‐down (USD) methods operating at the millilitre scale were used to characterise full‐scale processing of E. coli fermentation broths autolysed to different extents for release of a domain antibody. The focus was on the primary clarification stages involving continuous centrifugation followed by depth filtration. The performance of this sequence was predicted by USD studies to decrease significantly with increased extents of cell lysis. The use of polyethyleneimine reagent was studied to treat the lysed cell broth by precipitation of soluble contaminants such as DNA and flocculation of cell debris material. The USD studies were used to predict the impact of this treatment on the performance and here it was found that the fermentation could be run to maximum productivity using an acceptable clarification process (e.g., a centrifugation stage operating at 0.11 L/m2 equivalent gravity settling area per hour followed by a resultant required depth filter area of 0.07 m2/L supernatant). A range of USD predictions was verified at the pilot scale for centrifugation followed by depth filtration. © 2016 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers Biotechnol. Prog., 32:382–392, 2016 PMID:26698375

Utilization of agricultural wastes for production of ethanol. Progress report, October 1979-May 1980

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

Singh, B.

1980-05-01

The project proposes to develop methods to utilize agricultural wastes, especially cottonseed hulls and peanut shells to produce ethanol. Initial steps will involve development of methods to break down cellulose to a usable form of substrates for chemical or biological digestion. The process of ethanol production will consist of (a) preparatory step to separate fibrous (cellulose) and non-fibrous (non-cellulosic compounds). The non-cellulosic residues which may include grains, fats or other substrates for alcoholic fermentation. The fibrous residues will be first pre-treated to digest cellulose with acid, alkali, and sulfur dioxide gas or other solvents. (b) The altered cellulose will bemore » digested by suitable micro-organisms and cellulose enzymes before alcoholic fermentation. The digester and fermentative unit will be specially designed to develop a prototype for pilot plant for a continuous process. The first phase of the project will be devoted toward screening of a suitable method for cellulose modification, separation of fibrous and non-fibrous residues, the micro-organism and enzyme preparations. Work is in progress on: the effects of various microorganisms on the degree of saccharification; the effects of higher concentrations of acids, alkali, and EDTA on efficiency of microbial degradation; and the effects of chemicals on enzymatic digestion.« less

New challenges and opportunities for industrial biotechnology.

PubMed

Chen, Guo-Qiang

2012-08-20

Industrial biotechnology has not developed as fast as expected due to some challenges including the emergences of alternative energy sources, especially shale gas, natural gas hydrate (or gas hydrate) and sand oil et al. The weaknesses of microbial or enzymatic processes compared with the chemical processing also make industrial biotech products less competitive with the chemical ones. However, many opportunities are still there if industrial biotech processes can be as similar as the chemical ones. Taking advantages of the molecular biology and synthetic biology methods as well as changing process patterns, we can develop bioprocesses as competitive as chemical ones, these including the minimized cells, open and continuous fermentation processes et al.

Biohydrogen, biomethane and bioelectricity as crucial components of biorefinery of organic wastes: a review.

PubMed

Poggi-Varaldo, Héctor M; Munoz-Paez, Karla M; Escamilla-Alvarado, Carlos; Robledo-Narváez, Paula N; Ponce-Noyola, M Teresa; Calva-Calva, Graciano; Ríos-Leal, Elvira; Galíndez-Mayer, Juvencio; Estrada-Vázquez, Carlos; Ortega-Clemente, Alfredo; Rinderknecht-Seijas, Noemí F

2014-05-01

Biohydrogen is a sustainable form of energy as it can be produced from organic waste through fermentation processes involving dark fermentation and photofermentation. Very often biohydrogen is included as a part of biorefinery approaches, which reclaim organic wastes that are abundant sources of renewable and low cost substrate that can be efficiently fermented by microorganisms. The aim of this work was to critically assess selected bioenergy alternatives from organic solid waste, such as biohydrogen and bioelectricity, to evaluate their relative advantages and disadvantages in the context of biorefineries, and finally to indicate the trends for future research and development. Biorefining is the sustainable processing of biomass into a spectrum of marketable products, which means: energy, materials, chemicals, food and feed. Dark fermentation of organic wastes could be the beach-head of complete biorefineries that generate biohydrogen as a first step and could significantly influence the future of solid waste management. Series systems show a better efficiency than one-stage process regarding substrate conversion to hydrogen and bioenergy. The dark fermentation also produces fermented by-products (fatty acids and solvents), so there is an opportunity for further combining with other processes that yield more bioenergy. Photoheterotrophic fermentation is one of them: photosynthetic heterotrophs, such as non-sulfur purple bacteria, can thrive on the simple organic substances produced in dark fermentation and light, to give more H2. Effluents from photoheterotrophic fermentation and digestates can be processed in microbial fuel cells for bioelectricity production and methanogenic digestion for methane generation, thus integrating a diverse block of bioenergies. Several digestates from bioenergies could be used for bioproducts generation, such as cellulolytic enzymes and saccharification processes, leading to ethanol fermentation (another bioenergy), thus completing the inverse cascade. Finally, biohydrogen, biomethane and bioelectricity could contribute to significant improvements for solid organic waste management in agricultural regions, as well as in urban areas.

Fermentation pH Modulates the Size Distributions and Functional Properties of Gluconobacter albidus TMW 2.1191 Levan

PubMed Central

Ua-Arak, Tharalinee; Jakob, Frank; Vogel, Rudi F.

2017-01-01

Bacterial levan has gained an increasing interest over the last decades due to its unique characteristics and multiple possible applications. Levan and other exopolysaccharides (EPSs) production are usually optimized to obtain the highest concentration or yield while a possible change of the molecular size and mass during the production process is mostly neglected. In this study, the molar mass and radius of levan samples were monitored during fermentations with the food-grade, levan-producing acetic acid bacterium Gluconobacter (G.) albidus TMW 2.1191 in shake flasks (without pH control) and bioreactors (with pH control at 4.5, 5.5 and 6.5, respectively). In uncontrolled fermentations, the levan size/molar mass continuously decreased concomitantly with the continuous acidification of the nutrient medium. On the contrary, the amount, molar mass and size of levan could be directly influenced by controlling the pH during fermentation. Using equal initial substrate amounts, the largest weight average molar mass and geometric radius of levan were observed at constant pH 6.5, while the highest levan concentration was obtained at constant pH 4.5. Since there is a special demand to find suitable hydrocolloids from food-grade bacteria to develop novel gluten-free (GF) products, these differently produced levans were used for baking of GF breads, and the best quality improvement was obtained by addition of levan with the highest mass and radius. This work, therefore, demonstrates for the first time that one bacterial strain can produce specific high molecular weight fractions of one EPS type, which differ in properties and sizes among each other in dependence of the controllable production conditions. PMID:28522999

Immobilization of infant fecal microbiota and utilization in an in vitro colonic fermentation model.

PubMed

Cinquin, C; Le Blay, G; Fliss, I; Lacroix, C

2004-07-01

Bacteria isolated from infant feces were immobilized in polysaccharide gel beads (2.5% gellan gum, 0.25% xanthan gum) using a two-phase dispersion process. A 52-day continuous culture was carried out in a single-stage chemostat containing precolonized beads and fed with a medium formulated to approximate the composition of infant chyme. Different dilution rates and pH conditions were tested to simulate the proximal (PCS), transverse (TCS), and distal (DCS) colons. Immobilization preserved all nine bacterial groups tested with survival rates between 3 and 56%. After 1 week fermentation, beads were highly colonized with all populations tested (excepted Staphylococcus spp. present in low numbers), which remained stable throughout the 7.5 weeks of fermentation, with variations below 1 log unit. However, free-cell populations in the circulating liquid medium, produced by immobilized cell growth, cell-release activity from gel beads, and free-cell growth, were altered considerably by culture conditions. Compared to the stabilization period, PCS was characterized by a considerable and rapid increase in Bifidobacterium spp. concentrations (7.4 to 9.6 log CFU/mL), whereas Bifidobacterium spp., Lactobacillus spp., and Clostridium spp. concentrations decreased and Staphylococcus spp. and coliforms increased during TCS and DCS. Under pseudo-steady-state conditions, the community structure developed in the chemostat reflected the relative proportions of viable bacterial numbers and metabolites generally encountered in infant feces. This work showed that a complex microbiota such as infant fecal bacteria can be immobilized and used in a continuous in vitro intestinal fermentation model to reproduce the high bacterial concentration and bacterial diversity of the feces inoculum, at least at the genera level, with a high stability during long-term experiment.

Acetone production with metabolically engineered strains of Acetobacterium woodii.

PubMed

Hoffmeister, Sabrina; Gerdom, Marzena; Bengelsdorf, Frank R; Linder, Sonja; Flüchter, Sebastian; Öztürk, Hatice; Blümke, Wilfried; May, Antje; Fischer, Ralf-Jörg; Bahl, Hubert; Dürre, Peter

2016-07-01

Expected depletion of oil and fossil resources urges the development of new alternative routes for the production of bulk chemicals and fuels beyond petroleum resources. In this study, the clostridial acetone pathway was used for the formation of acetone in the acetogenic bacterium Acetobacterium woodii. The acetone production operon (APO) containing the genes thlA (encoding thiolase A), ctfA/ctfB (encoding CoA transferase), and adc (encoding acetoacetate decarboxylase) from Clostridium acetobutylicum were cloned under the control of the thlA promoter into four vectors having different replicons for Gram-positives (pIP404, pBP1, pCB102, and pCD6). Stable replication was observed for all constructs. A. woodii [pJIR_actthlA] achieved the maximal acetone concentration under autotrophic conditions (15.2±3.4mM). Promoter sequences of the genes ackA from A. woodii and pta-ack from C. ljungdahlii were determined by primer extension (PEX) and cloned upstream of the APO. The highest acetone production in recombinant A. woodii cells was achieved using the promoters PthlA and Ppta-ack. Batch fermentations using A. woodii [pMTL84151_actthlA] in a bioreactor revealed that acetate concentration had an effect on the acetone production, due to the high Km value of the CoA transferase. In order to establish consistent acetate concentration within the bioreactor and to increase biomass, a continuous fermentation process for A. woodii was developed. Thus, acetone productivity of the strain A. woodii [pMTL84151_actthlA] was increased from 1.2mgL(-1)h(-1) in bottle fermentation to 26.4mgL(-1)h(-1) in continuous gas fermentation. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Analysis of microbial diversity in Shenqu with different fermentation times by PCR-DGGE.

PubMed

Liu, Tengfei; Jia, Tianzhu; Chen, Jiangning; Liu, Xiaoyu; Zhao, Minjie; Liu, Pengpeng

Shenqu is a fermented product that is widely used in traditional Chinese medicine (TCM) to treat indigestion; however, the microbial strains in the fermentation process are still unknown. The aim of this study was to investigate microbial diversity in Shenqu using different fermentation time periods. DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) profiles indicated that a strain of Pediococcus acidilactici (band 9) is the predominant bacteria during fermentation and that the predominant fungi were uncultured Rhizopus, Aspergillus oryzae, and Rhizopus oryzae. In addition, pathogenic bacteria, such as Enterobacter cloacae, Klebsiella oxytoca, Erwinia billingiae, and Pantoea vagan were detected in Shenqu. DGGE analysis showed that bacterial and fungal diversity declined over the course of fermentation. This determination of the predominant bacterial and fungal strains responsible for fermentation may contribute to further Shenqu research, such as optimization of the fermentation process. Copyright © 2017. Published by Elsevier Editora Ltda.

A review on the fermentation of foods and the residues of pesticides-biotransformation of pesticides and effects on fermentation and food quality.

PubMed

Regueiro, Jorge; López-Fernández, Olalla; Rial-Otero, Raquel; Cancho-Grande, Beatriz; Simal-Gándara, Jesús

2015-01-01

Residues of pesticides in food are influenced by processing such as fermentation. Reviewing the extensive literature showed that in most cases, this step leads to large reductions in original residue levels in the fermented food, with the formation of new pesticide by-products. The behavior of residues in fermentation can be rationalized in terms of the physical-chemical properties of the pesticide and the nature of the process. In addition, the presence of pesticides decrease the growth rate of fermentative microbiota (yeasts and bacterias), which provokes stuck and sluggish fermentations. These changes have in consequence repercussions on several aspects of food sensory quality (physical-chemical properties, polyphenolic content, and aromatic profile) of fermented food. The main aim of this review is to deal with all these topics to propose challenging needs in science-based quality management of pesticides residues in food.

77 FR 25382 - Proposed Amendment to the Standards of Identity for Distilled Spirits

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-30

... manufactured using a small quantity of corn or corn syrup in the fermentation process. Since these products do... include as ``Cacha[ccedil]a'' any spirits that use corn or corn syrup in the fermentation process. TTB has... the use of corn or corn syrup in the fermentation process. As such, under the terms of the proposed...

DGGE and multivariate analysis of a yeast community in spontaneous cocoa fermentation process.

PubMed

Ferreira, A C R; Marques, E L S; Dias, J C T; Rezende, R P

2015-12-28

Cocoa bean is the main raw material used in the production of chocolate. In southern Bahia, Brazil, cocoa farming and processing is an important economic activity. The fermentation of cocoa is the processing stage that yields important chocolate flavor precursors and complex microbial involvement is essential for this process. In this study, PCR-denaturing gradient gel electrophoreses (DGGE) was used to investigate the diversity of yeasts present during the spontaneous fermentation of cocoa in southern Bahia. The DGGE analysis revealed a richness of 8 to 13 distinct bands of varied intensities among the samples; and samples taken at 24, 36, and 48 h into the fermentation process were found to group with 70% similarity and showed the greatest diversity of bands. Hierarchical clustering showed that all samples had common operational taxonomic units (OTUs) and the highest number of OTUs was found in the 48 h sample. Variations in pH and temperature observed within the fermenting mass over time possibly had direct effects on the composition of the existing microbial community. The findings reported here indicate that a heterogeneous yeast community is involved in the complex cocoa fermentation process, which is known to involve a succession of specialized microorganisms.

Industrial production of acetone and butanol by fermentation-100 years later.

PubMed

Sauer, Michael

2016-07-01

Microbial production of acetone and butanol was one of the first large-scale industrial fermentation processes of global importance. During the first part of the 20th century, it was indeed the second largest fermentation process, superseded in importance only by the ethanol fermentation. After a rapid decline after the 1950s, acetone-butanol-ethanol (ABE) fermentation has recently gained renewed interest in the context of biorefinery approaches for the production of fuels and chemicals from renewable resources. The availability of new methods and knowledge opens many new doors for industrial microbiology, and a comprehensive view on this process is worthwhile due to the new interest. This thematic issue of FEMS Microbiology Letters, dedicated to the 100th anniversary of the first industrial exploitation of Chaim Weizmann's ABE fermentation process, covers the main aspects of old and new developments, thereby outlining a model development in biotechnology. All major aspects of industrial microbiology are exemplified by this single process. This includes new technologies, such as the latest developments in metabolic engineering, the exploitation of biodiversity and discoveries of new regulatory systems such as for microbial stress tolerance, as well as technological aspects, such as bio- and down-stream processing. © FEMS 2016.

Evaluation of Mixed Probiotic Starter Cultures Isolated from Kimchi on Physicochemical and Functional Properties, and Volatile Compounds of Fermented Hams.

PubMed

Kim, Young Joo; Park, Sung Yong; Lee, Hong Chul; Yoo, Seung Seok; Oh, Sejong; Kim, Kwang Hyun; Chin, Koo Bok

2016-01-01

The objective of this study was to investigate the effects of mixed starter cultures isolated from kimchi on physicochemical properties, functionality and flavors of fermented ham. Physicochemical properties, microbial counts, shear force, cholesterol contents and volatile compounds of fermented ham were investigated during processing (curing and ripening time). Curing process for 7 d increased saltiness, however, decreased hunter color values (L, a, and b values). Ripening process for 21 d increased most parameters, such as saltiness, color values, weight loss, shear force and cholesterol content due to the drying process. The mixed starter culture had higher lactic acid bacteria than the commercial one. While eight volatile compounds were identified from fermented hams during curing process, total fiftyeight volatile compounds were identified from fermented hams during ripening process. The main volatile compounds were alcohols, esters and furans. However, no differences in volatile compounds were observed between two batches. Fermented hams (batch B) manufactured with probiotic starter culture (LPP) had higher sensory score in texture, color and overall acceptability than counterparts (batch A), while the opposite trend was observed in flavor. Therefore, mixed probiotic starter culture isolated from kimchi might be used as a starter culture to be able to replace with commercial starter culture (LK-30 plus) for the manufacture of fermented ham.

Evaluation of Mixed Probiotic Starter Cultures Isolated from Kimchi on Physicochemical and Functional Properties, and Volatile Compounds of Fermented Hams

PubMed Central

Yoo, Seung Seok

2016-01-01

The objective of this study was to investigate the effects of mixed starter cultures isolated from kimchi on physicochemical properties, functionality and flavors of fermented ham. Physicochemical properties, microbial counts, shear force, cholesterol contents and volatile compounds of fermented ham were investigated during processing (curing and ripening time). Curing process for 7 d increased saltiness, however, decreased hunter color values (L, a, and b values). Ripening process for 21 d increased most parameters, such as saltiness, color values, weight loss, shear force and cholesterol content due to the drying process. The mixed starter culture had higher lactic acid bacteria than the commercial one. While eight volatile compounds were identified from fermented hams during curing process, total fiftyeight volatile compounds were identified from fermented hams during ripening process. The main volatile compounds were alcohols, esters and furans. However, no differences in volatile compounds were observed between two batches. Fermented hams (batch B) manufactured with probiotic starter culture (LPP) had higher sensory score in texture, color and overall acceptability than counterparts (batch A), while the opposite trend was observed in flavor. Therefore, mixed probiotic starter culture isolated from kimchi might be used as a starter culture to be able to replace with commercial starter culture (LK-30 plus) for the manufacture of fermented ham. PMID:27499673

Nancy Dowe | NREL

Science.gov Websites

Center Bioprocess Development Group. The group is largely made up of fermentation scientists and engineers whose focus is on fermentation process development and pilot plant scale-up. Dowe has nearly 30 years of experience working with a wide variety of fermentation processes and microorganisms for the

Acetic acid bacteria in fermented foods and beverages.

PubMed

De Roos, Jonas; De Vuyst, Luc

2018-02-01

Although acetic acid bacteria (AAB) are commonly found in spontaneous or backslopped fermented foods and beverages, rather limited knowledge about their occurrence and functional role in natural food fermentation ecosystems is available. Not only is their cultivation, isolation, and identification difficult, their cells are often present in a viable but not culturable state. Yet, they are promising starter cultures either to better control known food fermentation processes or to produce novel fermented foods and beverages. This review summarizes the most recent findings on the occurrence and functional role of AAB in natural food fermentation processes such as lambic beer, water kefir, kombucha, and cocoa. Copyright © 2017 Elsevier Ltd. All rights reserved.

Real-Time Monitoring of Chemical Changes in Three Kinds of Fermented Milk Products during Fermentation Using Quantitative Difference Nuclear Magnetic Resonance Spectroscopy.

PubMed

Lu, Yi; Ishikawa, Hiroto; Kwon, Yeondae; Hu, Fangyu; Miyakawa, Takuya; Tanokura, Masaru

2018-02-14

Fermented milk products are rising in popularity throughout the world as a result of their health benefits, including improving digestion, normalizing the function of the immune system, and aiding in weight management. This study applies an in situ quantitative nuclear magnetic resonance method to monitor chemical changes in three kinds of fermented milk products, Bulgarian yogurt, Caspian Sea yogurt, and kefir, during fermentation. As a result, the concentration changes in nine organic compounds, α/β-lactose, α/β-galactose, lactic acid, citrate, ethanol, lecithin, and creatine, were monitored in real time. This revealed three distinct metabolic processes in the three fermented milk products. Moreover, pH changes were also determined by variations in the chemical shift of citric acid during the fermentation processes. These results can be applied to estimate microbial metabolism in various flora and help guide the fermentation and storage of various fermented milk products to improve their quality, which may directly influence human health.

Accumulation of Citrulline by Microbial Arginine Metabolism during Alcoholic Fermentation of Soy Sauce.

PubMed

Fang, Fang; Zhang, Jiran; Zhou, Jingwen; Zhou, Zhaohui; Li, Tieqiao; Lu, Liling; Zeng, Weizhu; Du, Guocheng; Chen, Jian

2018-03-07

Citrulline, the major precursor of ethyl carbamate in soy sauce, is an intermediate catabolite of arginine produced by bacteria present in soy sauce moromi mash. Pediococcus acidilactici is responsible for the formation of citrulline during the lactic acid fermentation process of soy sauce. However, citrulline accumulation during the alcoholic fermentation process and the corresponding bacteria involved have not been identified. Salt-tolerant, arginine-utilizing bacteria were isolated from moromi mash during the alcoholic fermentation process. Under normal cultivation conditions, arginine utilization by these strains did not contribute to citrulline accumulation. However, the conversion of arginine to citrulline by these bacteria increased when cultivated during the alcoholic fermentation process. Additionally, the ethanol-enhanced solubility of free fatty acids in moromi mash stimulated the accumulation of citrulline. Staphylococcus exhibited the highest capability in the conversion of arginine to citrulline.

Application of gamma irradiation for aging control and improvement of shelf-life of kimchi, korean salted and fermented vegetables

NASA Astrophysics Data System (ADS)

Song, Hyun-Pa; Kim, Dong-Ho; Yook, Hong-Sun; Kim, Kyung-Soo; Kwon, Joong-Ho; Byun, Myung-Woo

2004-09-01

This study was carried out to evaluate the application of food irradiation as a method for extending shelf life of Kimchi. Gamma irradiation up to 10 kGy in the early stage of Kimchi fermentation had a dose-dependent effect on the inactivation of fermentative microbes, lowering the lactate dehydrogenase (LDH) activity and delaying acidification. Although gamma irradiation on the mid-fermentation stage of Kimchi inactivated the fermentative microbes effectively, LDH activity remained high and acidification continued. Kimchi irradiated at 10 kGy had lower scores in acceptability than those of control, 2.5 and 5 kGy irradiated. Therefore, gamma irradiation upto 5 kGy in the early fermentation stage is recommended for aging control and the improvement of shelf life of Kimchi.

A critical review on factors influencing fermentative hydrogen production.

PubMed

Kothari, Richa; Kumar, Virendra; Pathak, Vinayak V; Ahmad, Shamshad; Aoyi, Ochieng; Tyagi, V V

2017-03-01

Biohydrogen production by dark fermentation of different waste materials is a promising approach to produce bio-energy in terms of renewable energy exploration. This communication has reviewed various influencing factors of dark fermentation process with detailed account of determinants in biohydrogen production. It has also focused on different factors such as improved bacterial strain, reactor design, metabolic engineering and two stage processes to enhance the bioenergy productivity from substrate. The study also suggest that complete utilization of substrates for biological hydrogen production requires the concentrated research and development for efficient functioning of microorganism with integrated application for energy production and bioremediation. Various studies have been taken into account here, to show the comparative efficiency of different substrates and operating conditions with inhibitory factors and pretreatment option for biohydrogen production. The study reveals that an extensive research is needed to observe field efficiency of process using low cost substrates and integration of dark and photo fermentation process. Integrated approach of fermentation process will surely compete with conventional hydrogen process and replace it completely in future.

Dental caries: a dynamic disease process.

PubMed

Featherstone, J D B

2008-09-01

Abstract Dental caries is a transmissible bacterial disease process caused by acids from bacterial metabolism diffusing into enamel and dentine and dissolving the mineral. The bacteria responsible produce organic acids as a by-product of their metabolism of fermentable carbohydrates. The caries process is a continuum resulting from many cycles of demineralization and remineralization. Demineralization begins at the atomic level at the crystal surface inside the enamel or dentine and can continue unless halted with the end-point being cavitation. There are many possibilities to intervene in this continuing process to arrest or reverse the progress of the lesion. Remineralization is the natural repair process for non-cavitated lesions, and relies on calcium and phosphate ions assisted by fluoride to rebuild a new surface on existing crystal remnants in subsurface lesions remaining after demineralization. These remineralized crystals are acid resistant, being much less soluble than the original mineral.

Xanthophyllomyces dendrorhous for the industrial production of astaxanthin.

PubMed

Rodríguez-Sáiz, Marta; de la Fuente, Juan Luis; Barredo, José Luis

2010-10-01

Astaxanthin is a red xanthophyll (oxygenated carotenoid) with large importance in the aquaculture, pharmaceutical, and food industries. The green alga Haematococcus pluvialis and the heterobasidiomycetous yeast Xanthophyllomyces dendrorhous are currently known as the main microorganisms useful for astaxanthin production at the industrial scale. The improvement of astaxanthin titer by microbial fermentation is a requirement to be competitive with the synthetic manufacture by chemical procedures, which at present is the major source in the market. In this review, we show how the isolation of new strains of X. dendrorhous from the environment, the selection of mutants by the classical methods of random mutation and screening, and the rational metabolic engineering, have provided improved strains with higher astaxanthin productivity. To reduce production costs and enhance competitiveness from an industrial point of view, low-cost raw materials from industrial and agricultural origin have been adopted to get the maximal astaxanthin productivity. Finally, fermentation parameters have been studied in depth, both at flask and fermenter scales, to get maximal astaxanthin titers of 4.7 mg/g dry cell matter (420 mg/l) when X. dendrorhous was fermented under continuous white light. The industrial scale-up of this biotechnological process will provide a cost-effective method, alternative to synthetic astaxanthin, for the commercial exploitation of the expensive astaxanthin (about $2,500 per kilogram of pure astaxanthin).

[Novel resources utilization technique for rural domestic refuse].

PubMed

Qiu, Cai-Di; He, Ruo; Chen, Song-Mei; Lou, Bin; Shen, Dong-Sheng

2009-03-15

In order to speed up rural domestic refuse resources utilization, intermittent aeration and continuous aeration were applied to treat rural domestic refuse after anaerobic fermentation. Three kinds of refuse were selected on base of fermentative age, i.e. three months, five months and seven months. Results showed that aeration could remove water and organic materials of the refuse effectively. Points of view on aeration, continuous aeration was better than intermittent aeration, and on the other side, water removal rate increased with ventilation and decreased with fermentative age in the condition of intermittent aeration. On organic materials removal point, it was affected by fermentative age significantly, i. e. increase of fermentative age could resulted in decrease in the removal efficiency. In conclusion, intermittent aeration of 0.06 m3/(min x m3) was considered to be feasible for treatment. The water removal efficiency of three months, five months and seven months fermentative age refuse could be up to 49.1%, 45.3% and 44.0%, and organic compound removal efficiency was 41.9%, 24.8% and 13.1%, respectively, after intermittent aeration for 21 d. Moreover, concentrated effect was presented on major nutrient ingredients, such as total nitrogen, phosphorus, and potassium during the aeration, which realized for resources utilization.

Improvement in fermentation characteristics of degermed ground corn by lipid supplementation.

PubMed

Murthy, Ganti S; Singh, Vijay; Johnston, David B; Rausch, Kent D; Tumbleson, M E

2006-08-01

With rapid growth of fuel ethanol industry, and concomitant increase in distillers dried grains with solubles (DDGS), new corn fractionation technologies that reduce DDGS volume and produce higher value coproducts in dry grind ethanol process have been developed. One of the technologies, a dry degerm, defiber (3D) process (similar to conventional corn dry milling) was used to separate germ and pericarp fiber prior to the endosperm fraction fermentation. Recovery of germ and pericarp fiber in the 3D process results in removal of lipids from the fermentation medium. Biosynthesis of lipids, which is important for cell growth and viability, cannot proceed in strictly anaerobic fermentations. The effects of ten different lipid supplements on improving fermentation rates and ethanol yields were studied and compared to the conventional dry grind process. Endosperm fraction (from the 3D process) was mixed with water and liquefied by enzymatic hydrolysis and was fermented using simultaneous saccharification and fermentation. The highest ethanol concentration (13.7% v/v) was achieved with conventional dry grind process. Control treatment (endosperm fraction from 3D process without lipid supplementation) produced the lowest ethanol concentration (11.2% v/v). Three lipid treatments (fatty acid ester, alkylphenol, and ethoxylated sorbitan ester 1836) were most effective in improving final ethanol concentrations. Fatty acid ester treatment produced the highest final ethanol concentration (12.3% v/v) among all lipid supplementation treatments. Mean final ethanol concentrations of alkylphenol and ethoxylated sorbitan ester 1836 supplemented samples were 12.3 and 12.0% v/v, respectively.

Monitoring of Lactobacillus fermentation process by using ion chromatography with a series piezoelectric quartz crystal detector.

PubMed

Zhang, J; Xie, Y; Dai, X; Wei, W

2001-03-01

A new method monitoring Lactobacillus fermentation process, which combines ion chromatography (IC) with a series piezoelectric quartz crystal (SPQC) technique, is presented in this paper. Monitoring of the fermentation process was realized by examining the rate of production of lactic acid. An automatic membrane dialyser was used for the pretreatment of the sample in on-line monitoring. A mixture of p-hydroxybenzoic acid and N,N-diethylethanolamine was adopted as mobile phase and its flow rate was 0.8 ml/min. The effects of some fermentation conditions were also discussed in detail. Accordingly, the optimal fermentation conditions were obtained. This method is simple and convenient while the results obtained are accurate and reliable.

Bacteriophages in food fermentations: new frontiers in a continuous arms race.

PubMed

Samson, Julie E; Moineau, Sylvain

2013-01-01

Phage contamination represents an important risk to any process requiring bacterial growth, particularly in the biotechnology and food industries. The presence of unwanted phages may lead to manufacturing delays, lower quality product, or, in the worst cases, total production loss. Thus, constant phage monitoring and stringent application of the appropriate control measures are indispensable. In fact, a systematic preventive approach to phage contamination [phage analysis and critical control points (PACCP)] should be put in place. In this review, sources of phage contamination and novel phage detection methods are described, with an emphasis on bacterial viruses that infect lactic acid bacteria used in food fermentations. Recent discoveries related to antiphage systems that are changing our views on phage-host interactions are highlighted. Finally, future directions are also discussed.

Mathematical models of ABE fermentation: review and analysis.

PubMed

Mayank, Rahul; Ranjan, Amrita; Moholkar, Vijayanand S

2013-12-01

Among different liquid biofuels that have emerged in the recent past, biobutanol produced via fermentation processes is of special interest due to very similar properties to that of gasoline. For an effective design, scale-up, and optimization of the acetone-butanol-ethanol (ABE) fermentation process, it is necessary to have insight into the micro- and macro-mechanisms of the process. The mathematical models for ABE fermentation are efficient tools for this purpose, which have evolved from simple stoichiometric fermentation equations in the 1980s to the recent sophisticated and elaborate kinetic models based on metabolic pathways. In this article, we have reviewed the literature published in the area of mathematical modeling of the ABE fermentation. We have tried to present an analysis of these models in terms of their potency in describing the overall physiology of the process, design features, mode of operation along with comparison and validation with experimental results. In addition, we have also highlighted important facets of these models such as metabolic pathways, basic kinetics of different metabolites, biomass growth, inhibition modeling and other additional features such as cell retention and immobilized cultures. Our review also covers the mathematical modeling of the downstream processing of ABE fermentation, i.e. recovery and purification of solvents through flash distillation, liquid-liquid extraction, and pervaporation. We believe that this review will be a useful source of information and analysis on mathematical models for ABE fermentation for both the appropriate scientific and engineering communities.

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

PubMed

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

2015-10-12

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

Effect of phytase application during high gravity (HG) maize mashes preparation on the availability of starch and yield of the ethanol fermentation process.

PubMed

Mikulski, D; Kłosowski, G; Rolbiecka, A

2014-10-01

Phytic acid present in raw materials used in distilling industry can form complexes with starch and divalent cations and thus limit their biological availability. The influence of the enzymatic hydrolysis of phytate complexes on starch availability during the alcoholic fermentation process using high gravity (HG) maize mashes was analyzed. Indicators of the alcoholic fermentation as well as the fermentation activity of Saccharomyces cerevisiae D-2 strain were statistically evaluated. Phytate hydrolysis improved the course of the alcoholic fermentation of HG maize mashes. The final ethanol concentration in the media supplemented with phytase applied either before or after the starch hydrolysis increased by 1.0 and 0.6 % v/v, respectively, as compared to the control experiments. This increase was correlated with an elevated fermentation yield that was higher by 5.5 and 2.0 L EtOH/100 kg of starch, respectively. Phytate hydrolysis resulted also in a statistically significant increase in the initial concentration of fermenting sugars by 14.9 mg/mL of mash, on average, which was a consequence of a better availability of starch for enzymatic hydrolysis. The application of phytase increased the attenuation of HG media fermentation thus improving the economical aspect of the ethanol fermentation process.

The cocoa bean fermentation process: from ecosystem analysis to starter culture development.

PubMed

De Vuyst, L; Weckx, S

2016-07-01

Cocoa bean fermentation is still a spontaneous curing process to facilitate drying of nongerminating cocoa beans by pulp removal as well as to stimulate colour and flavour development of fermented dry cocoa beans. As it is carried out on farm, cocoa bean fermentation is subjected to various agricultural and operational practices and hence fermented dry cocoa beans of variable quality are obtained. Spontaneous cocoa bean fermentations carried out with care for approximate four days are characterized by a succession of particular microbial activities of three groups of micro-organisms, namely yeasts, lactic acid bacteria (LAB) and acetic acid bacteria (AAB), which results in well-fermented fully brown cocoa beans. This has been shown through a plethora of studies, often using a multiphasic experimental approach. Selected strains of several of the prevailing microbial species have been tested in appropriate cocoa pulp simulation media to unravel their functional roles and interactions as well as in small plastic vessels containing fresh cocoa pulp-bean mass to evaluate their capacity to dominate the cocoa bean fermentation process. Various starter cultures have been proposed for successful fermentation, encompassing both cocoa-derived and cocoa nonspecific strains of (hybrid) yeasts, LAB and AAB, some of which have been implemented on farms successfully. © 2016 The Society for Applied Microbiology.

Continuous ethanol fermentation of lactose by a recombinant flocculating Saccharomyces cerevisiae strain

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

Domingues, L.; Dantas, M.M.; Lima, N.

1999-09-20

Alcohol fermentation of lactose was investigated using a recombinant flocculating Saccharomyces cetevisiae, expressing the LAC4 (coding the {beta}-galactosidase) and LAC12 (coding for lactose permease) genes of Kluyveromyces marxianus. Data on yeast fermentation and growth on a medium containing lactose as the sole carbon source are presented. In the range of studied lactose concentrations, total lactose consumption was observed with a conversion yield of ethanol close to the expected theoretical value. For the continuously operating bioreactor, an ethanol productivity of 11 g L{sup {minus}1} h{sup {minus}1} (corresponding to a feed lactose concentration of 50 g L{sup {minus}1} and a dilution ratemore » of 0.55 h{sup {minus}1}) was obtained, which is 7 times larger than the continuous conventional systems. The system stability was confirmed by keeping it in operation for 6 months.« less

Integration of Gas Enhanced Oil Recovery in Multiphase Fermentations for the Microbial Production of Fuels and Chemicals.

PubMed

Pedraza-de la Cuesta, Susana; Keijzers, Lore; van der Wielen, Luuk A M; Cuellar, Maria C

2018-04-01

In multiphase fermentations where the product forms a second liquid phase or where solvents are added for product extraction, turbulent conditions disperse the oil phase as droplets. Surface-active components (SACs) present in the fermentation broth can stabilize the product droplets thus forming an emulsion. Breaking this emulsion increases process complexity and consequently the production cost. In previous works, it has been proposed to promote demulsification of oil/supernatant emulsions in an off-line batch bubble column operating at low gas flow rate. The aim of this study is to test the performance of this recovery method integrated to a fermentation, allowing for continuous removal of the oil phase. A 500 mL bubble column is successfully integrated with a 2 L reactor during 24 h without affecting cell growth or cell viability. However, higher levels of surfactants and emulsion stability are measured in the integrated system compared to a base case, reducing its capacity for oil recovery. This is related to release of SACs due to cellular stress when circulating through the recovery column. Therefore, it is concluded that the gas bubble-induced oil recovery method allows for oil separation and cell recycling without compromising fermentation performance; however, tuning of the column parameters considering increased levels of SACs due to cellular stress is required for improving oil recovery. © 2018 The Authors. Biotechnology Journal Published by Wiley-VCHVerlag GmbH & Co. KGaA, Weinheim.

Can a fermentation gas mainly produced by rumen Isotrichidae ciliates be a potential source of biohydrogen and a fuel for a chemical fuel cell?

PubMed

Piela, Piotr; Michałowski, Tadeusz; Miltko, Renata; Szewczyk, Krzysztof; Sikora, Radosław; Grzesiuk, Elzbieta; Sikora, Anna

2010-07-01

Bacteria, fungi and protozoa inhabiting the rumen, the largest chamber of the ruminants' stomach, release large quantities of hydrogen during the fermentation of carbohydrates. The hydrogen is used by coexisting methanogens to produce methane in energy-yielding processes. This work shows, for the first time, a fundamental possibility of using a hydrogen-rich fermentation gas produced by selected rumen ciliates to feed a low-temperature hydrogen fuel cell. A biohydrogen fuel cell (BHFC) was constructed consisting of (i) a bioreactor, in which a hydrogen-rich gas was produced from glucose by rumen ciliates, mainly of the Isotrichidae family, deprived of intra- and extracellular bacteria, methanogens, and fungi, and (ii) a chemical fuel cell of the polymer-electrolyte type (PEFC). The fuel cell was used as a tester of the technical applicability of the fermentation gas produced by the rumen ciliates for power generation. The average estimated hydrogen yield was ca. 1.15 mol H2 per mol of fermented glucose. The BHFC performance was equal to the performance of the PEFC running on pure hydrogen. No fuel cell poisoning effects were detected. A maximum power density of 1.66 kW/m2 (PEFC geometric area) was obtained at room temperature. The maximum volumetric power density was 128 W/m3 but the coulombic efficiency was only ca. 3.8%. The configuration of the bioreactor limited the continuous operation time of this BHFC to ca. 14 hours.

Profiling of dynamic changes in the microbial community during the soy sauce fermentation process.

PubMed

Wei, Quanzeng; Wang, Hongbin; Chen, Zhixin; Lv, Zhijia; Xie, Yufeng; Lu, Fuping

2013-10-01

Soy sauce is a traditional condiment manufactured by natural inoculation and mixed culture fermentation. As is well known, it is the microbial community that plays an important role in the formation of its flavors. However, to date, its dynamic changes during the long period of fermentation process are still unclear, intensively constraining the improvement and control of the soy sauce quality. In this work, we revealed the dynamic changes of the microbial community by combining a cultured dependent method and a cultured independent method of polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis. Results indicated that the two methods verified and complemented each other in profiling microbial community, and that significant dynamics of the microbial community existed during the fermentation process, especially the strong inhibition of the growth of most of the microbes when entering into the mash stage from the koji stage. In the analysis of bacterial community, Staphylococcus and Bacillus were found to be the dominant bacteria and detected in the whole fermentation process. Kurthia and Klebsiella began to appear in the koji stage and then fade away in the early stage of the mash fermentation. In the analysis of fungal community, Aspergillus sojae and Zygosaccharomyces rouxii were found to be the dominant fungi in the koji and mash fermentation, respectively. It was clearly shown that when A. sojae decreased and disappeared in the middle stage of the mash fermentation, Z. rouxii appeared and increased at the meantime. Aspergillus parasiticus, Trichosporon ovoides and Trichosporon asahii also appeared in the koji and the early period of the mash fermentation and disappeared thereafter. Similar to Z. rouxii, Millerozyma farinosa and Peronospora farinosa were also found spontaneously which appeared in the mid-late period of the mash fermentation. The principal component analysis suggested that the microbial community underwent significant changes in the early period of the fermentation and, thereafter, tended to the stabilization in the mid-late periods. This study gave us important clues to understand the fermentation process and can serve as a foundation for improving the quality of soy sauce in the future.

75 FR 55988 - Approval and Promulgation of Implementation Plans; Commonwealth of Kentucky; Prevention of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-15

... exclude facilities that produce ethanol through a natural fermentation process from the definition of... action on Kentucky's provisions to exclude facilities that produce ethanol through a natural fermentation... facilities that produce ethanol through a natural fermentation process from the definition of ``chemical...

Feed component inhibition in ethanolic fermentation by Saccharomyces cerevisiae

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

Maiorella, B.L.; Blanch, H.W.; Wilke, C.R.

1984-01-01

Inhibition by secondary feed components can limit productivity and restrict process options for the production of ethanol by fermentation. New fermentation processes (such as vacuum or extractive fermentation), while selectively removing ethanol, can concentrate nonmetabolized feed components in the remaining broth. Stillage recycle to reduce stillage waste treatment results in buildup of nonmetabolized feed components. Continuous culture experiments are presented establishing an inhibition order: CaCl/sub 2/, (NH/sub 4/)/sub 2/SO/sub 4/ > NaCl, NH/sub 4/Cl > KH/sub 2/PO/sub 4/ > xylose, MgCl/sub 2/ > MgSO/sub 4/ > KCl. Reduction of the water activity alone is not an adequate predictor of themore » variation in inhibitory concentration among the different components tested. As a general trend, specific ethanol productivity increases and cell production decreases as inhibitors are added at higher concentration. It is postulated that these results can be interpreted in terms of an increase in energy requirements for cell maintenance under hypertonic (stressed) conditions. Ion and carbohydrate transport and specific toxic effects are reviewed as they related to the postulated inhibition mechanism. Glycerol production increases under hypertonic conditions and glycerol is postulated to function as a nontoxic osmoregulator. Calcium was the most inhibitory component tested, causing an 80% decline in cell mass production at 0.23 mol Ca/sup 2 +//L and calcium is present at substantial concentration in many carbohydate sources. For a typical final cane molasses feed, stillage recycle must be limited to less than one-third of the feed rate; otherwise inhibitory effects will be observed.« less

Dominance of rumen microorganisms during cheese whey acidification: acidogenesis can be governed by a rare Selenomonas lacticifex-type fermentation.

PubMed

Ntougias, Spyridon; Tsiamis, George; Soultani, Despoina; Melidis, Paraschos

2015-11-01

The microbial basis of acidification process during spontaneous cheese whey wastewater fermentation was decrypted by implementing both culture-dependent and culture-independent techniques. Lac tobacillus and Bifidobacterium were the predominant taxa among the microbiota growing on MRS (deMan, Rogosa, and Sharpe), while Kazachstania unispora and Dekkera anomala yeast species were also isolated. Almost all Lactobacillus isolates were heterofermentative that could ferment glucose and lactose, with most of them being related to Lactobacillus hilgardii (99.0-100 % similarity). By employing fluorescence techniques, the dominance of long crescent-shaped bacteria in the acidogenic sludge was observed. Temperature gradient gel electrophoresis (TGGE), clone library, and next-generation sequencing techniques revealed the dominance of Selenomonas lacticifex. Based on Illumina data, Selenomonas in the continuous stirred-tank reactor (CSTR) represented 70.13 ± 4.64 % of the bacterial reads, while other Veillonellaceae taxa (Megasphaera and Pectinatus) represented a notable proportion (6.54 %). Prevotella was only detected by Illumina sequencing as an important constituent of the microbial population (14.97 ± 1.71 %). Budding yeasts represented 97 % of the fungal population in the CSTR, with Yarrowia strains representing 88.85 ± 5.52 % of the fungal reads. Spontaneous cheese whey acidification can favor the dominance of rumen bacteria and here was driven by the rarely reported S. lacticifex-type fermentation, which should be taken into consideration during evaluation of acidogenesis in process simulation and modelling. Moreover, the important nervonic acid content detected indicates that acidogenic sludge can be used as a source for the production of high value-added biomedical substrates.

Gene modification of the acetate biosynthesis pathway in Escherichia coli and implementation of the cell recycling technology to increase L-tryptophan production

PubMed Central

Bai, Fang; Chen, Ning; Bai, Gang

2017-01-01

The implementation of a novel cell recycling technology based on a special disk centrifuge during microbial fermentation process can continuously separate the product and harmful intermediates, while maintaining the cell viability owing to the installed cooling system. Acetate accumulation is an often encountered problem in L-tryptophan fermentation by Escherichia coli. To extend our previous studies, the current study deleted the key genes underlying acetate biosynthesis to improve l-tryptophan production. The deletion of the phosphotransacetylase (pta)–acetate kinase (ackA) pathway in a gltB (encoding glutamate synthase) mutant of E. coli TRTHB, led to the highest production of l-tryptophan (47.18 g/L) and glucose conversion rate (17.83%), with a marked reduction in acetate accumulation (1.22 g/L). This strain, TRTHBPA, was then used to investigate the effects of the cell recycling process on L-tryptophan fermentation. Four different strategies were developed concerning two issues, the volume ratio of the concentrated cell solution and clear solution and the cell recycling period. With strategy I (concentrated cell solution: clear solution, 1: 1; cell recycling within 24–30 h), L-tryptophan production and the glucose conversion rate increased to 55.12 g/L and 19.75%, respectively, 17.55% and 10.77% higher than those without the cell recycling. In addition, the biomass increased by 13.52% and the fermentation period was shortened from 40 h to 32 h. These results indicated that the cell recycling technology significantly improved L-tryptophan production by E. coli. PMID:28622378

Process simulation of modified dry grind ethanol plant with recycle of pretreated and enzymatically hydrolyzed distillers' grains.

PubMed

Kim, Youngmi; Mosier, Nathan; Ladisch, Michael R

2008-08-01

Distillers' grains (DG), a co-product of a dry grind ethanol process, is an excellent source of supplemental proteins in livestock feed. Studies have shown that, due to its high polymeric sugar contents and ease of hydrolysis, the distillers' grains have potential as an additional source of fermentable sugars for ethanol fermentation. The benefit of processing the distillers' grains to extract fermentable sugars lies in an increased ethanol yield without significant modification in the current dry grind technology. Three different potential configurations of process alternatives in which pretreated and hydrolyzed distillers' grains are recycled for an enhanced overall ethanol yield are proposed and discussed in this paper based on the liquid hot water (LHW) pretreatment of distillers' grains. Possible limitations of each proposed process are also discussed. This paper presents a compositional analysis of distillers' grains, as well as a simulation of the modified dry grind processes with recycle of distillers' grains. Simulated material balances for the modified dry grind processes are established based on the base case assumptions. These balances are compared to the conventional dry grind process in terms of ethanol yield, compositions of its co-products, and accumulation of fermentation inhibitors. Results show that 14% higher ethanol yield is achievable by processing and hydrolyzing the distillers' grains for additional fermentable sugars, as compared to the conventional dry grind process. Accumulation of fermentation by-products and inhibitory components in the proposed process is predicted to be 2-5 times higher than in the conventional dry grind process. The impact of fermentation inhibitors is reviewed and discussed. The final eDDGS (enhanced dried distillers' grains) from the modified processes has 30-40% greater protein content per mass than DDGS, and its potential as a value-added process is also analyzed. While the case studies used to illustrate the process simulation are based on LHW pretreated DG, the process simulation itself provides a framework for evaluation of the impact of other pretreatments.

State of the art in on-line techniques coupled to flow injection analysis FIA/on-line- a critical review

PubMed Central

Puchades, R.; Maquieira, A.; Atienza, J.; Herrero, M. A.

1990-01-01

Flow injection analysis (FIA) has emerged as an increasingly used laboratory tool in chemical analysis. Employment of the technique for on-line sample treatment and on-line measurement in chemical process control is a growing trend. This article reviews the recent applications of FlA. Most papers refer to on-line sample treatment. Although FIA is very well suited to continuous on-line process monitoring, few examples have been found in this areamost of them have been applied to water treatment or fermentation processes. PMID:18925271

Metabolomics approach to reduce the Crabtree effect in continuous culture of Saccharomyces cerevisiae.

PubMed

Imura, Makoto; Iwakiri, Ryo; Bamba, Takeshi; Fukusaki, Eiichiro

2018-04-20

The budding yeast Saccharomyces cerevisiae is an important microorganism for fermentation and the food industry. However, during production, S. cerevisiae commonly uses the ethanol fermentation pathway for glucose utilization if excess sugar is present, even in the presence of sufficient oxygen levels. This aerobic ethanol fermentation, referred to as "the Crabtree effect" is one of the most significant reasons for low cell yield. To weaken the Crabtree effect in fed-batch and continuous culture, sugar flow should be limited. In addition, in continuous culture, the dilution rate must be reduced to avoid washing out cells. However, under such conditions, production speed might be sacrificed. It is difficult to solve this problem with the tradeoff between cell yield and production speed by using conventional tactics. However, a metabolomics approach may be an effective way to search for clues regarding metabolic modulation. Therefore, the purpose of this study was to reduce ethanol production in continuous culture of S. cerevisiae at a higher dilution rate through a metabolomics approach. We used a metabolomics analysis to identify metabolites that were drastically increased or decreased in continuous culture when the dilution rate shifted from biomass formation to ethanol fermentation. The individual addition of two of the selected metabolites, fumaric acid and malic acid, reduced ethanol production at a higher dilution rate. This result demonstrates the potential for using metabolomics approaches to identify metabolites that reduce ethanol production in continuous culture at high dilution rates. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

East Europe Report. Scientific Affairs, No. 785.

DTIC Science & Technology

1983-08-11

in close cooperation with the Institute of Microbiology, is developing an ASU for fermentation processes. Contracts have already been entered into...and such sys- tems are being devised for the plants in Peshtera and in Razgrad. Associated with fermentation processes is the technology for...experimental fermentation system is already in operation in Vidin and methane is being produced. But a number of problems in optimizing these processes with

Continuous processing of recombinant proteins: Integration of inclusion body solubilization and refolding using simulated moving bed size exclusion chromatography with buffer recycling.

PubMed

Wellhoefer, Martin; Sprinzl, Wolfgang; Hahn, Rainer; Jungbauer, Alois

2013-12-06

An integrated process which combines continuous inclusion body dissolution with NaOH and continuous matrix-assisted refolding based on closed-loop simulated moving bed size exclusion chromatography was designed and experimentally evaluated at laboratory scale. Inclusion bodies from N(pro) fusion pep6His and N(pro) fusion MCP1 from high cell density fermentation were continuously dissolved with NaOH, filtered and mixed with concentrated refolding buffer prior to refolding by size exclusion chromatography (SEC). This process enabled an isocratic operation of the simulated moving bed (SMB) system with a closed-loop set-up with refolding buffer as the desorbent buffer and buffer recycling by concentrating the raffinate using tangential flow filtration. With this continuous refolding process, we increased the refolding and cleavage yield of both model proteins by 10% compared to batch dilution refolding. Furthermore, more than 99% of the refolding buffer of the raffinate could be recycled which reduced the buffer consumption significantly. Based on the actual refolding data, we compared throughput, productivity, and buffer consumption between two batch dilution refolding processes - one using urea for IB dissolution, the other one using NaOH for IB dissolution - and our continuous refolding process. The higher complexity of the continuous refolding process was rewarded with higher throughput and productivity as well as significantly lower buffer consumption compared to the batch dilution refolding processes. Copyright © 2013 Elsevier B.V. All rights reserved.

Implementation and process analysis of pilot scale multi-phase anaerobic fermentation and digestion of faecal sludge in Ghana

PubMed Central

Shih, Justin; Fanyin-Martin, Ato; Taher, Edris; Chandran, Kartik

2017-01-01

Background.  In Ghana, faecal sludge (FS) from on-site sanitation facilities is often discharged untreated into the environment, leading to significant insults to environmental and human health. Anaerobic digestion offers an attractive pathway for FS treatment with the concomitant production of energy in the form of methane. Another innovative option includes separating digestion into acidogenesis (production of volatile fatty acids (VFA)) and methanogenesis (production of methane), which could ultimately facilitate the production of an array of biofuels and biochemicals from the VFA. This work describes the development, implementation and modeling based analysis of a novel multiphase anaerobic fermentation-digestion process aimed at FS treatment in Kumasi, Ghana.  Methods.  A pilot-scale anaerobic fermentation process was implemented at the Kumasi Metropolitan Assembly’s Oti Sanitary Landfill Site at Adanse Dompoase.  The process consisted of six 10 m reactors in series, which were inoculated with bovine rumen and fed with fecal sludge obtained from public toilets.  The performance of the fermentation process was characterized in terms of both aqueous and gaseous variables representing the conversion of influent organic carbon to VFA as well as CH 4.  Using the operating data, the first-ever process model for FS fermentation and digestion was developed and calibrated, based on the activated sludge model framework. Results and Conclusions.  This work represents one of the first systematic efforts at integrated FS characterization and process modeling to enable anaerobic fermentation and digestion of FS. It is shown that owing to pre-fermentation of FS in public septage holding tanks, one could employ significantly smaller digesters (lower capital costs) or increased loading capabilities for FS conversion to biogas or VFA. Further, using the first-ever calibrated process model for FS fermentation and digestion presented herein, we expect improved and more mechanistically informed development and application of different process designs and configurations for global FS management practice. PMID:29528044

Implementation and process analysis of pilot scale multi-phase anaerobic fermentation and digestion of faecal sludge in Ghana.

PubMed

Shih, Justin; Fanyin-Martin, Ato; Taher, Edris; Chandran, Kartik

2017-11-06

Background.  In Ghana, faecal sludge (FS) from on-site sanitation facilities is often discharged untreated into the environment, leading to significant insults to environmental and human health. Anaerobic digestion offers an attractive pathway for FS treatment with the concomitant production of energy in the form of methane. Another innovative option includes separating digestion into acidogenesis (production of volatile fatty acids (VFA)) and methanogenesis (production of methane), which could ultimately facilitate the production of an array of biofuels and biochemicals from the VFA. This work describes the development, implementation and modeling based analysis of a novel multiphase anaerobic fermentation-digestion process aimed at FS treatment in Kumasi, Ghana.  Methods.  A pilot-scale anaerobic fermentation process was implemented at the Kumasi Metropolitan Assembly's Oti Sanitary Landfill Site at Adanse Dompoase.  The process consisted of six 10 m reactors in series, which were inoculated with bovine rumen and fed with fecal sludge obtained from public toilets.  The performance of the fermentation process was characterized in terms of both aqueous and gaseous variables representing the conversion of influent organic carbon to VFA as well as CH 4 .  Using the operating data, the first-ever process model for FS fermentation and digestion was developed and calibrated, based on the activated sludge model framework. Results and Conclusions.  This work represents one of the first systematic efforts at integrated FS characterization and process modeling to enable anaerobic fermentation and digestion of FS. It is shown that owing to pre-fermentation of FS in public septage holding tanks, one could employ significantly smaller digesters (lower capital costs) or increased loading capabilities for FS conversion to biogas or VFA. Further, using the first-ever calibrated process model for FS fermentation and digestion presented herein, we expect improved and more mechanistically informed development and application of different process designs and configurations for global FS management practice.

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

PubMed Central

Gohel, Vipul; Duan, Gang

2012-01-01

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

The complexities of hydrolytic enzymes from the termite digestive system.

PubMed

Saadeddin, Anas

2014-06-01

The main challenge in second generation bioethanol production is the efficient breakdown of cellulose to sugar monomers (hydrolysis). Due to the recalcitrant character of cellulose, feedstock pretreatment and adapted hydrolysis steps are needed to obtain fermentable sugar monomers. The conventional industrial production process of second-generation bioethanol from biomass comprises several steps: thermochemical pretreatment, enzymatic hydrolysis and sugar fermentation. This process is undergoing continuous optimization in order to increase the bioethanol yield and reduce the economic cost. Therefore, the discovery of new enzymes with high lignocellulytic activity or new strategies is extremely important. In nature, wood-feeding termites have developed a sophisticated and efficient cellulose degrading system in terms of the rate and extent of cellulose hydrolysis and exploitation. This system, which represents a model for digestive symbiosis has attracted the attention of biofuel researchers. This review describes the termite digestive system, gut symbionts, termite enzyme resources, in vitro studies of isolated enzymes and lignin degradation in termites.

Updates on industrial production of amino acids using Corynebacterium glutamicum.

PubMed

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

2016-06-01

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

Modelling of Batch Lactic Acid Fermentation in
the Presence of Anionic Clay

PubMed Central

Jinescu, Cosmin; Aruş, Vasilica Alisa; Nistor, Ileana Denisa

2014-01-01

Summary Batch fermentation of milk inoculated with lactic acid bacteria was conducted in the presence of hydrotalcite-type anionic clay under static and ultrasonic conditions. An experimental study of the effect of fermentation temperature (t=38–43 °C), clay/milk ratio (R=1–7.5 g/L) and ultrasonic field (ν=0 and 35 kHz) on process dynamics was performed. A mathematical model was selected to describe the fermentation process kinetics and its parameters were estimated based on experimental data. A good agreement between the experimental and simulated results was achieved. Consequently, the model can be employed to predict the dynamics of batch lactic acid fermentation with values of process variables in the studied ranges. A statistical analysis of the data based on a 23 factorial experiment was performed in order to express experimental and model-regressed process responses depending on t, R and ν factors. PMID:27904318

Taming wild yeast: potential of conventional and nonconventional yeasts in industrial fermentations.

PubMed

Steensels, Jan; Verstrepen, Kevin J

2014-01-01

Yeasts are the main driving force behind several industrial food fermentation processes, including the production of beer, wine, sake, bread, and chocolate. Historically, these processes developed from uncontrolled, spontaneous fermentation reactions that rely on a complex mixture of microbes present in the environment. Because such spontaneous processes are generally inconsistent and inefficient and often lead to the formation of off-flavors, most of today's industrial production utilizes defined starter cultures, often consisting of a specific domesticated strain of Saccharomyces cerevisiae, S. bayanus, or S. pastorianus. Although this practice greatly improved process consistency, efficiency, and overall quality, it also limited the sensorial complexity of the end product. In this review, we discuss how Saccharomyces yeasts were domesticated to become the main workhorse of food fermentations, and we investigate the potential and selection of nonconventional yeasts that are often found in spontaneous fermentations, such as Brettanomyces, Hanseniaspora, and Pichia spp.

Effect of chemical pretreatments on corn stalk bagasse as immobilizing carrier of Clostridium acetobutylicum in the performance of a fermentation-pervaporation coupled system.

PubMed

Cai, Di; Li, Ping; Chen, Changjing; Wang, Yong; Hu, Song; Cui, Caixia; Qin, Peiyong; Tan, Tianwei

2016-11-01

In this study, different pretreatment methods were evaluated for modified the corn stalk bagasse and further used the pretreated bagasse as immobilized carrier in acetone-butanol-ethanol fermentation process. Structural changes of the bagasses pretreated by different methods were analyzed by Fourier transform infrared, crystallinity index and scanning pictures by electron microscope. And the performances of batch fermentation using the corn stalk based carriers were evaluated. Results indicated that the highest ABE concentration of 23.86g/L was achieved using NaOH pretreated carrier in batch fermentation. Immobilized fermentation-pervaporation integration process was further carried out. The integration process showed long-term stability with 225-394g/L of ABE solvents on the permeate side of pervaporation membrane. This novel integration process was found to be an efficient method for biobutanol production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Process simulation of ethanol production from biomass gasification and syngas fermentation.

PubMed

Pardo-Planas, Oscar; Atiyeh, Hasan K; Phillips, John R; Aichele, Clint P; Mohammad, Sayeed

2017-12-01

The hybrid gasification-syngas fermentation platform can produce more bioethanol utilizing all biomass components compared to the biochemical conversion technology. Syngas fermentation operates at mild temperatures and pressures and avoids using expensive pretreatment processes and enzymes. This study presents a new process simulation model developed with Aspen Plus® of a biorefinery based on a hybrid conversion technology for the production of anhydrous ethanol using 1200tons per day (wb) of switchgrass. The simulation model consists of three modules: gasification, fermentation, and product recovery. The results revealed a potential production of about 36.5million gallons of anhydrous ethanol per year. Sensitivity analyses were also performed to investigate the effects of gasification and fermentation parameters that are keys for the development of an efficient process in terms of energy conservation and ethanol production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microbial fuel cell treatment of ethanol fermentation process water

DOEpatents

Borole, Abhijeet P [Knoxville, TN

2012-06-05

The present invention relates to a method for removing inhibitor compounds from a cellulosic biomass-to-ethanol process which includes a pretreatment step of raw cellulosic biomass material and the production of fermentation process water after production and removal of ethanol from a fermentation step, the method comprising contacting said fermentation process water with an anode of a microbial fuel cell, said anode containing microbes thereon which oxidatively degrade one or more of said inhibitor compounds while producing electrical energy or hydrogen from said oxidative degradation, and wherein said anode is in electrical communication with a cathode, and a porous material (such as a porous or cation-permeable membrane) separates said anode and cathode.

Dynamic model of temperature impact on cell viability and major product formation during fed-batch and continuous ethanolic fermentation in Saccharomyces cerevisiae.

PubMed

Amillastre, Emilie; Aceves-Lara, César-Arturo; Uribelarrea, Jean-Louis; Alfenore, Sandrine; Guillouet, Stéphane E

2012-08-01

The impact of the temperature on an industrial yeast strain was investigated in very high ethanol performance fermentation fed-batch process within the range of 30-47 °C. As previously observed with a lab strain, decoupling between growth and glycerol formation occurred at temperature of 36 °C and higher. A dynamic model was proposed to describe the impact of the temperature on the total and viable biomass, ethanol and glycerol production. The model validation was implemented with experimental data sets from independent cultures under different temperatures, temperature variation profiles and cultivation modes. The proposed model fitted accurately the dynamic evolutions for products and biomass concentrations over a wide range of temperature profiles. R2 values were above 0.96 for ethanol and glycerol in most experiments. The best results were obtained at 37 °C in fed-batch and chemostat cultures. This dynamic model could be further used for optimizing and monitoring the ethanol fermentation at larger scale. Copyright © 2012 Elsevier Ltd. All rights reserved.

Acidogenic fermentation of iron-enhanced primary sedimentation sludge under different pH conditions for production of volatile fatty acids.

PubMed

Lin, Lin; Li, Xiao-Yan

2018-03-01

Iron-based chemically enhanced primary sedimentation (CEPS) is increasingly adopted for wastewater treatment in mega cities, producing a large amount of sludge (Fe-sludge) with a high content of organics for potential organic resource recovery. In this experimental study, acidogenic fermentation was applied treat FeCl 3 -based CEPS sludge for production of volatile fatty acids (VFAs) at different pHs. Batch fermentation tests on the Fe-sludge with an organic content of 10 g-COD/L showed that the maximum VFAs production reached 2782.2 mg-COD/L in the reactor without pH control, and it reached 688.4, 3095.3, and 2603.7 mg-COD/L in reactors with pHs kept at 5.0, 6.0 and 8.0, respectively. Analysis of the acidogenesis kinetics and enzymatic activity indicated that the alkaline pH could accelerate the rate of organic hydrolysis but inhibited the further organic conversion to VFAs. In semi-continuous sludge fermentation tests, the VFAs yield in the pH6 reactor was 20% higher than that in the control reactor without pH regulation, while the VFAs yield in the pH8 reactor was 10% lower than the control. Illumina MiSeq sequencing revealed that key functional microorganisms known for effective sludge fermentation, including Bacteroidia and Erysipelotrichi, were enriched in the pH6 reactor with an enhanced VFAs production, while Clostridia became more abundant in the pH8 reactor to stand the unfavorable pH condition. The research presented acidogenic fermentation as an effective process for CEPS sludge treatment and organic resource recovery and provided the first insight into the related microbial community dynamics. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed

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

2010-07-01

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

Production and partial characterization of serine and metallo peptidases secreted by Aspergillus fumigatus Fresenius in submerged and solid state fermentation.

PubMed

da Silva, Ronivaldo Rodrigues; de Freitas Cabral, Tatiana Pereira; Rodrigues, André; Cabral, Hamilton

2013-01-01

Enzyme production varies in different fermentation systems. Enzyme expression in different fermentation systems yields important information for improving our understanding of enzymatic production induction. Comparative studies between solid-state fermentation (SSF) using agro-industrial waste wheat bran and submerged fermentation (SmF) using synthetic media were carried out to determinate the best parameters for peptidase production by the fungus Aspergillus fumigatus Fresen. Variables tested include: the concentration of carbon and protein nitrogen sources, the size of the inoculum, the pH of the media, temperature, and the length of the fermentation process. The best peptidase production during SSF was obtained after 96 hours using wheat bran at 30 °C with an inoculum of 1 × 10(6) spores and yielded 1500 active units (U/mL). The best peptidase production using SmF was obtained after periods of 72 and 96 hours of fermentation in media containing 0.5% and 0.25% of casein, respectively, at a pH of 6.0 and at 30 °C and yielded 40 U/mL. We also found examples of catabolite repression of peptidase production under SmF conditions. Biochemical characterization of the peptidases produced by both fermentative processes showed optimum activity at pH 8.0 and 50 °C, and also showed that their proteolytic activity is modulated by surfactants. The enzymatic inhibition profile using phenylmethylsulfonyl fluoride (PMSF) in SmF and SSF indicated that both fermentative processes produced a serine peptidase. Additionally, the inhibitory effect of the ethylene-diaminetetraacetic acid (EDTA) chelating agent on the peptidase produced by SmF indicated that this fermentative process also produced a metallopeptidase.

Effect of molasses supplementation on ruminal fermentation

USDA-ARS?s Scientific Manuscript database

This fact sheet summarizes the results of two continuous culture fermentor studies that evaluated the effects of molasses supplementation on ruminal fermentation of a pasture diet. The first study compared molasses with corn supplementation. Diets consisted of pasture only, molasses plus pasture, co...

U.S. Army Medical Research Institute of Infectious Disease Annual Progress Report, Fiscal Year 1985

DTIC Science & Technology

1985-10-01

response. 25. (U) 8410-8509-Tangential flow filtration was developed as a safer method of harvesting the 50-L anthrax fermenter cultures...yearly boosters. Efforts over several years have sought to improve this chemical vaccine through optimization of fermenter and recovery techniques so...A collaborative effort with WLAIR led to production of candidate human hybridomas to PA. Progrses: The 50-liter fermenter continues to be used

Introducing capnophilic lactic fermentation in a combined dark-photo fermentation process: a route to unparalleled H2 yields.

PubMed

Dipasquale, L; Adessi, A; d'Ippolito, G; Rossi, F; Fontana, A; De Philippis, R

2015-01-01

Two-stage process based on photofermentation of dark fermentation effluents is widely recognized as the most effective method for biological production of hydrogen from organic substrates. Recently, it was described an alternative mechanism, named capnophilic lactic fermentation, for sugar fermentation by the hyperthermophilic bacterium Thermotoga neapolitana in CO2-rich atmosphere. Here, we report the first application of this novel process to two-stage biological production of hydrogen. The microbial system based on T. neapolitana DSM 4359(T) and Rhodopseudomonas palustris 42OL gave 9.4 mol of hydrogen per mole of glucose consumed during the anaerobic process, which is the best production yield so far reported for conventional two-stage batch cultivations. The improvement of hydrogen yield correlates with the increase in lactic production during capnophilic lactic fermentation and takes also advantage of the introduction of original conditions for culturing both microorganisms in minimal media based on diluted sea water. The use of CO2 during the first step of the combined process establishes a novel strategy for biohydrogen technology. Moreover, this study opens the way to cost reduction and use of salt-rich waste as feedstock.

The effect of fermentation and addition of vegetable oil on resistant starch formation in wholegrain breads.

PubMed

Buddrick, Oliver; Jones, Oliver A H; Hughes, Jeff G; Kong, Ing; Small, Darryl M

2015-08-01

Resistant starch has potential health benefits but the factors affecting its formation in bread and baked products are not well studied. Here, the formation of resistant starch in wholemeal bread products was evaluated in relation to the processing conditions including fermentation time, temperature and the inclusion of palm oil as a vitamin source. The effects of each the factor were assessed using a full factorial design. The impact on final starch content of traditional sourdough fermentation of wholemeal rye bread, as well as the bulk fermentation process of wheat and wheat/oat blends of wholemeal bread, was also assessed by enzyme assay. Palm oil content was found to have a significant effect on the formation of resistant starch in all of the breads while fermentation time and temperature had no significant impact. Sourdough fermentation of rye bread was found to have a greater impact on resistant starch formation than bulk fermentation of wheat and wheat blend breads, most likely due the increased organic acid content of the sourdough process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Commercialization of the Conversion of Bagasse to Ethanol. Summary quarterly report for the period January-September 1999

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

NONE

2000-02-01

These studies were intended to further refine sugar yield parameters which effect sugar yield such as feedstock particle size, debris, acid soak time, temperature, dewatering, and pretreatment conditions (such as temperature, reaction time, percentage solids concentration, acid concentration), liquid-solids separation, and detoxification parameters (such as time temperature and mixing of detoxification ingredients). Validate and refine parameters, which affect ethanol yield such as detoxification conditions mentioned above, and to fermenter conditions such as temperature, pH adjustment, aeration, nutrients, and charging sequence. Materials of construction will be evaluated also. Evaluate stillage to determine clarification process and suitability for recycle; evaluate lignocellulosic cakemore » for thermal energy recovery to produce heat and electricity for the process; and Support Studies at UF - Toxin Amelioration and Fermentation; TVA work will provide pre-hydroylsates for the evaluation of BCI proprietary methods of toxin amelioration. Pre-hydrolysates from batch studies will allow the determination of the range of allowable hydrolyze conditions that can be used to produce a fermentable sugar stream. This information is essential to guide selection of process parameters for refinement and validation in the continuous pretreatment reactor, and for overall process design. Additional work will be conducted at UFRFI to develop improved strains that are resistant to inhibitors. The authors are quite optimistic about the long-term prospects for this advancement having recently developed strains with a 25%--50% increase in ethanol production. The biocatalyst platform selected originally, genetically engineered Escherichia coli B, has proven to be quite robust and adaptable.« less

Hydrogen production from sugar beet juice using an integrated biohydrogen process of dark fermentation and microbial electrolysis cell.

PubMed

Dhar, Bipro Ranjan; Elbeshbishy, Elsayed; Hafez, Hisham; Lee, Hyung-Sool

2015-12-01

An integrated dark fermentation and microbial electrochemical cell (MEC) process was evaluated for hydrogen production from sugar beet juice. Different substrate to inoculum (S/X) ratios were tested for dark fermentation, and the maximum hydrogen yield was 13% of initial COD at the S/X ratio of 2 and 4 for dark fermentation. Hydrogen yield was 12% of initial COD in the MEC using fermentation liquid end products as substrate, and butyrate only accumulated in the MEC. The overall hydrogen production from the integrated biohydrogen process was 25% of initial COD (equivalent to 6 mol H2/mol hexoseadded), and the energy recovery from sugar beet juice was 57% using the combined biohydrogen. Copyright © 2015 Elsevier Ltd. All rights reserved.

High-Throughput Sequencing of Microbial Community Diversity and Dynamics during Douchi Fermentation.

PubMed

Yang, Lin; Yang, Hui-Lin; Tu, Zong-Cai; Wang, Xiao-Lan

2016-01-01

Douchi is a type of Chinese traditional fermented food that is an important source of protein and is used in flavouring ingredients. The end product is affected by the microbial community present during fermentation, but exactly how microbes influence the fermentation process remains poorly understood. We used an Illumina MiSeq approach to investigate bacterial and fungal community diversity during both douchi-koji making and fermentation. A total of 181,443 high quality bacterial 16S rRNA sequences and 221,059 high quality fungal internal transcribed spacer reads were used for taxonomic classification, revealing eight bacterial and three fungal phyla. Firmicutes, Actinobacteria and Proteobacteria were the dominant bacterial phyla, while Ascomycota and Zygomycota were the dominant fungal phyla. At the genus level, Staphylococcus and Weissella were the dominant bacteria, while Aspergillus and Lichtheimia were the dominant fungi. Principal coordinate analysis showed structural separation between the composition of bacteria in koji making and fermentation. However, multivariate analysis of variance based on unweighted UniFrac distances did identify distinct differences (p <0.05), and redundancy analysis identified two key genera that are largely responsible for the differences in bacterial composition between the two steps. Staphylococcus was enriched in koji making, while Corynebacterium was enriched in fermentation. This is the first investigation to integrate douchi fermentation and koji making and fermentation processes through this technological approach. The results provide insight into the microbiome of the douchi fermentation process, and reveal a structural separation that may be stratified by the environment during the production of this traditional fermented food.

High-Throughput Sequencing of Microbial Community Diversity and Dynamics during Douchi Fermentation

PubMed Central

Tu, Zong-cai; Wang, Xiao-lan

2016-01-01

Douchi is a type of Chinese traditional fermented food that is an important source of protein and is used in flavouring ingredients. The end product is affected by the microbial community present during fermentation, but exactly how microbes influence the fermentation process remains poorly understood. We used an Illumina MiSeq approach to investigate bacterial and fungal community diversity during both douchi-koji making and fermentation. A total of 181,443 high quality bacterial 16S rRNA sequences and 221,059 high quality fungal internal transcribed spacer reads were used for taxonomic classification, revealing eight bacterial and three fungal phyla. Firmicutes, Actinobacteria and Proteobacteria were the dominant bacterial phyla, while Ascomycota and Zygomycota were the dominant fungal phyla. At the genus level, Staphylococcus and Weissella were the dominant bacteria, while Aspergillus and Lichtheimia were the dominant fungi. Principal coordinate analysis showed structural separation between the composition of bacteria in koji making and fermentation. However, multivariate analysis of variance based on unweighted UniFrac distances did identify distinct differences (p <0.05), and redundancy analysis identified two key genera that are largely responsible for the differences in bacterial composition between the two steps. Staphylococcus was enriched in koji making, while Corynebacterium was enriched in fermentation. This is the first investigation to integrate douchi fermentation and koji making and fermentation processes through this technological approach. The results provide insight into the microbiome of the douchi fermentation process, and reveal a structural separation that may be stratified by the environment during the production of this traditional fermented food. PMID:27992473

Image analysis and mathematical modelling for the supervision of the dough fermentation process

NASA Astrophysics Data System (ADS)

Zettel, Viktoria; Paquet-Durand, Olivier; Hecker, Florian; Hitzmann, Bernd

2016-10-01

The fermentation (proof) process of dough is one of the quality-determining steps in the production of baking goods. Beside the fluffiness, whose fundaments are built during fermentation, the flavour of the final product is influenced very much during this production stage. However, until now no on-line measurement system is available, which can supervise this important process step. In this investigation the potential of an image analysis system is evaluated, that enables the determination of the volume of fermented dough pieces. The camera is moving around the fermenting pieces and collects images from the objects by means of different angles (360° range). Using image analysis algorithms the volume increase of individual dough pieces is determined. Based on a detailed mathematical description of the volume increase, which based on the Bernoulli equation, carbon dioxide production rate of yeast cells and the diffusion processes of carbon dioxide, the fermentation process is supervised. Important process parameters, like the carbon dioxide production rate of the yeast cells and the dough viscosity can be estimated just after 300 s of proofing. The mean percentage error for forecasting the further evolution of the relative volume of the dough pieces is just 2.3 %. Therefore, a forecast of the further evolution can be performed and used for fault detection.

Reduction of verotoxigenic Escherichia coli in production of fermented sausages.

PubMed

Holck, Askild L; Axelsson, Lars; Rode, Tone Mari; Høy, Martin; Måge, Ingrid; Alvseike, Ole; L'abée-Lund, Trine M; Omer, Mohamed K; Granum, Per Einar; Heir, Even

2011-11-01

After a number of foodborne outbreaks of verotoxigenic Escherichia coli involving fermented sausages, some countries have imposed regulations on sausage production. For example, the US Food Safety and Inspection Service requires a 5 log(10) reduction of E. coli in fermented products. Such regulations have led to a number of studies on the inactivation of E. coli in fermented sausages by changing processing and post-processing conditions. Several factors influence the survival of E. coli such as pre-treatment of the meat, amount of NaCl, nitrite and lactic acid, water activity, pH, choice of starter cultures and addition of antimicrobial compounds. Also process variables like fermentation temperature and storage time play important roles. Though a large variety of different production processes of sausages exist, generally the reduction of E. coli caused by production is in the range 1-2 log(10). In many cases this may not be enough to ensure microbial food safety. By optimising ingredients and process parameters it is possible to increase E. coli reduction to some extent, but in some cases still other post process treatments may be required. Such treatments may be storage at ambient temperatures, specific heat treatments, high pressure processing or irradiation. HACCP analyses have identified the quality of the raw materials, low temperature in the batter when preparing the sausages and a rapid pH drop during fermentation as critical control points in sausage production. This review summarises the literature on the reduction verotoxigenic E. coli in production of fermented sausages. Copyright © 2011 Elsevier Ltd. All rights reserved.

Demonstration of Parallel Algal Processing: Production of Renewable Diesel Blendstock and a High-Value Chemical Intermediate

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

Knoshaug, Eric P; Mohagheghi, Ali; Nagle, Nicholas J

Co-production of high-value chemicals such as succinic acid from algal sugars is a promising route to enabling conversion of algal lipids to a renewable diesel blendstock. Biomass from the green alga Scenedesmus acutus was acid pretreated and the resulting slurry separated into its solid and liquor components using charged polyamide induced flocculation and vacuum filtration. Over the course of a subsequent 756 hours continuous fermentation of the algal liquor with Actinobacillus succinogenes 130Z, we achieved maximum productivity, process conversion yield, and titer of 1.1 g L-1 h-1, 0.7 g g-1 total sugars, and 30.5 g L-1 respectively. Succinic acid wasmore » recovered from fermentation media with a yield of 60% at 98.4% purity while lipids were recovered from the flocculated cake at 83% yield with subsequent conversion through deoxygenation and hydroisomerization to a renewable diesel blendstock. This work is a first-of-its-kind demonstration of a novel integrated conversion process for algal biomass to produce fuel and chemical products of sufficient quality to be blend-ready feedstocks for further processing.« less

Hypotriacylglycerolemic and antiobesity properties of a new fermented tea product obtained by tea-rolling processing of third-crop green tea (Camellia sinensis) leaves and loquat (Eriobotrya japonica) leaves.

PubMed

Tanaka, Kazunari; Tamaru, Shizuka; Nishizono, Shoko; Miyata, Yuji; Tamaya, Kei; Matsui, Toshiro; Tanaka, Takashi; Echizen, Yoshie; Ikeda, Ikuo

2010-01-01

We manufactured a new fermented tea by tea-rolling processing of third-crop green tea (Camellia sinensis) leaves and loquat (Eriobotrya japonica) leaves. The mixed fermented tea extract inhibited pancreatic lipase activity in vitro, and effectively suppressed postprandial hypertriacylglycerolemia in rats. Rats fed a diet containing 1% freeze-dried fermented tea extract for 4 weeks had a significantly lower liver triacylglycerol concentration and white adipose tissue weight than those fed the control diet lacking fermented tea extract. The activity of fatty acid synthase in hepatic cytosol markedly decreased in the fermented tea extract group as compared to the control group. The serum and liver triacylglycerol- and body fat-lowering effects of the mixed fermented tea extract were strong relative to the level of dietary supplementation. These results suggest that the new fermented tea product exhibited hypotriacylglycerolemic and antiobesity properties through suppression of both liver fatty acid synthesis and postprandial hypertriacylglycerolemia by inhibition of pancreatic lipase.

Time-dependent fermentation control strategies for enhancing synthesis of marine bacteriocin 1701 using artificial neural network and genetic algorithm.

PubMed

Peng, Jiansheng; Meng, Fanmei; Ai, Yuncan

2013-06-01

The artificial neural network (ANN) and genetic algorithm (GA) were combined to optimize the fermentation process for enhancing production of marine bacteriocin 1701 in a 5-L-stirred-tank. Fermentation time, pH value, dissolved oxygen level, temperature and turbidity were used to construct a "5-10-1" ANN topology to identify the nonlinear relationship between fermentation parameters and the antibiotic effects (shown as in inhibition diameters) of bacteriocin 1701. The predicted values by the trained ANN model were coincided with the observed ones (the coefficient of R(2) was greater than 0.95). As the fermentation time was brought in as one of the ANN input nodes, fermentation parameters could be optimized by stages through GA, and an optimal fermentation process control trajectory was created. The production of marine bacteriocin 1701 was significantly improved by 26% under the guidance of fermentation control trajectory that was optimized by using of combined ANN-GA method. Copyright © 2013 Elsevier Ltd. All rights reserved.

Dry-grind processing using amylase corn and superior yeast to reduce the exogenous enzyme requirements in bioethanol production.

PubMed

Kumar, Deepak; Singh, Vijay

2016-01-01

Conventional corn dry-grind ethanol production process requires exogenous alpha and glucoamylases enzymes to breakdown starch into glucose, which is fermented to ethanol by yeast. This study evaluates the potential use of new genetically engineered corn and yeast, which can eliminate or minimize the use of these external enzymes, improve the economics and process efficiencies, and simplify the process. An approach of in situ ethanol removal during fermentation was also investigated for its potential to improve the efficiency of high-solid fermentation, which can significantly reduce the downstream ethanol and co-product recovery cost. The fermentation of amylase corn (producing endogenous α-amylase) using conventional yeast and no addition of exogenous α-amylase resulted in ethanol concentration of 4.1 % higher compared to control treatment (conventional corn using exogenous α-amylase). Conventional corn processed with exogenous α-amylase and superior yeast (producing glucoamylase or GA) with no exogenous glucoamylase addition resulted in ethanol concentration similar to control treatment (conventional yeast with exogenous glucoamylase addition). Combination of amylase corn and superior yeast required only 25 % of recommended glucoamylase dose to complete fermentation and achieve ethanol concentration and yield similar to control treatment (conventional corn with exogenous α-amylase, conventional yeast with exogenous glucoamylase). Use of superior yeast with 50 % GA addition resulted in similar increases in yield for conventional or amylase corn of approximately 7 % compared to that of control treatment. Combination of amylase corn, superior yeast, and in situ ethanol removal resulted in a process that allowed complete fermentation of 40 % slurry solids with only 50 % of exogenous GA enzyme requirements and 64.6 % higher ethanol yield compared to that of conventional process. Use of amylase corn and superior yeast in the dry-grind processing industry can reduce the total external enzyme usage by more than 80 %, and combining their use with in situ removal of ethanol during fermentation allows efficient high-solid fermentation.

Production of Butyric Acid and Butanol from Biomass

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

Ramey, David E.; Yang, Shang-Tian

Butanol replaced gasoline gallon for gallon in a 10,000 miles trip across the United States without the need to highly modify a ’92 Buick (your existing car today). Butanol can now be made for less than ethanol and yields more Btu’s from the same corn, making the plow to tire equation positive – more energy out than it takes to make it and Butanol is much safer. Butanol when substituted for gasoline gives better gas mileage and does not pollute as tested in 10 states. Butanol should now receive the same recognition as ethanol in U.S. legislation “ethanol/butanol”. There ismore » abundant plant biomass present as low-value agricultural commodities or processing wastes requiring proper disposal to avoid pollution problems. One example is in the corn refinery industry, which processes more than 13% of the ~9.5 billion bushels (~240 million metric tons) of corn annually produced in the U.S. to produce high-fructose-corn-syrup, dextrose, starch, and fuel alcohol, and generates more than 10 million metric tons of corn byproducts that are currently of limited use and pose significant environmental problems. The abundant inexpensive renewable resources as feedstock for fermentation, and recent advances in the fields of biotechnology and bioprocessing have resulted in a renewed interest in the fermentation production of chemicals and fuels, including n-butanol. The historic acetone-butanol-ethanol (ABE) fermentation by Clostridium acetobutylicum is one of the oldest known industrial fermentations. It was ranked second only to ethanol fermentation by yeast in its scale of production, and is one of the largest biotechnological processes ever known. However, since the 1950's industrial ABE fermentation has declined continuously, and almost all butanol is now produced via petrochemical routes (Chemical Marketing Reporter, 1993). Butanol is an important industrial solvent and is a better fuel for replacing gasoline – gallon for gallon than ethanol. Current butanol prices as a chemical are at $3.00 per gallon – wholesaling in 55 gallon drums for $6.80, with a worldwide market of 1.4 billion gallon per year. The market demand is expected to increase dramatically since butanol can now be produced economically from low-cost biomass. Butanol’s application as a replacement for gasoline will outpace ethanol, biodiesel and hydrogen when its safety and simplicity of use are seen. Butanol’s application for the Department of Defense as a clean-safe replacement for batteries when used in conjunction with fuel cell technology is seen as an application for the future. Disposable canisters made of PLA that carry butanol to be reformed and used to generate electricity for computers, night vision and stealth equipment can be easily disposed of. In a typical ABE fermentation, butyric, propionic and acetic acids are produced first by C. acetobutylicum; the culture then undergoes a metabolic shift and solvents (butanol, acetone, and ethanol) are formed (Fond et al., 1985). In conventional ABE fermentations, the butanol yield from glucose is low, typically at ~15% (w/w) and rarely exceeds 25% (0.77–1.3 gallons per bushel corn respectfully). The production of butanol is also limited by severe product inhibition. Butanol at a concentration of 10 g/L can significantly inhibit cell growth and the fermentation. Consequently, butanol titers in conventional ABE fermentations are usually lower than 13 g/L. The low butanol yield and butanol concentration made butanol production from glucose by ABE fermentation uneconomical.« less

Dry fermentation of manure with straw in continuous plug flow reactor: Reactor development and process stability at different loading rates.

PubMed

Patinvoh, Regina J; Kalantar Mehrjerdi, Adib; Sárvári Horváth, Ilona; Taherzadeh, Mohammad J

2017-01-01

In this work, a plug flow reactor was developed for continuous dry digestion processes and its efficiency was investigated using untreated manure bedded with straw at 22% total solids content. This newly developed reactor worked successfully for 230days at increasing organic loading rates of 2.8, 4.2 and 6gVS/L/d and retention times of 60, 40 and 28days, respectively. Organic loading rates up to 4.2gVS/L/d gave a better process stability, with methane yields up to 0.163LCH 4 /gVS added /d which is 56% of the theoretical yield. Further increase of organic loading rate to 6gVS/L/d caused process instability with lower volatile solid removal efficiency and cellulose degradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

75 FR 73017 - Approval and Promulgation of Implementation Plans; Georgia: Prevention of Significant...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-29

... produce ethanol through a natural fermentation process from the definition of ``chemical process plants... facilities that produce ethanol through a natural fermentation process from the definition of ``chemical...

Biological hydrogen production by dark fermentation: challenges and prospects towards scaled-up production.

PubMed

RenNanqi; GuoWanqian; LiuBingfeng; CaoGuangli; DingJie

2011-06-01

Among different technologies of hydrogen production, bio-hydrogen production exhibits perhaps the greatest potential to replace fossil fuels. Based on recent research on dark fermentative hydrogen production, this article reviews the following aspects towards scaled-up application of this technology: bioreactor development and parameter optimization, process modeling and simulation, exploitation of cheaper raw materials and combining dark-fermentation with photo-fermentation. Bioreactors are necessary for dark-fermentation hydrogen production, so the design of reactor type and optimization of parameters are essential. Process modeling and simulation can help engineers design and optimize large-scale systems and operations. Use of cheaper raw materials will surely accelerate the pace of scaled-up production of biological hydrogen. And finally, combining dark-fermentation with photo-fermentation holds considerable promise, and has successfully achieved maximum overall hydrogen yield from a single substrate. Future development of bio-hydrogen production will also be discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

The water kefir grain inoculum determines the characteristics of the resulting water kefir fermentation process.

PubMed

Laureys, D; De Vuyst, L

2017-03-01

To investigate the influence of the water kefir grain inoculum on the characteristics of the water kefir fermentation process. Three water kefir fermentation processes were started with different water kefir grain inocula and followed as a function of time regarding microbial species diversity, community dynamics, substrate consumption profile and metabolite production course. The inoculum determined the water kefir grain growth, the viable counts on the grains, the time until total carbohydrate exhaustion, the final metabolite concentrations and the microbial species diversity. There were always 2-10 lactic acid bacterial cells for every yeast cell and the majority of these micro-organisms was always present on the grains. Lactobacillus paracasei, Lactobacillus hilgardii, Lactobacillus nagelii and Saccharomyces cerevisiae were always present and may be the key micro-organisms during water kefir fermentation. Low water kefir grain growth was associated with small grains with high viable counts of micro-organisms, fast fermentation and low pH values, and was not caused by the absence of exopolysaccharide-producing lactic acid bacteria. The water kefir grain inoculum influences the microbial species diversity and characteristics of the fermentation process. A select group of key micro-organisms was always present during fermentation. This study allows a rational selection of a water kefir grain inoculum. © 2016 The Society for Applied Microbiology.

Fermented Foods: Patented Approaches and Formulations for Nutritional Supplementation and Health Promotion

PubMed Central

Borresen, Erica C.; Henderson, Angela J.; Kumar, Ajay; Weir, Tiffany L.; Ryan, Elizabeth P.

2016-01-01

Fermentation has had a long history in human food production and consumption. Fermented foods and beverages can comprise anywhere between 5-40% of the human diet in some populations. Not only is this process beneficial for extending shelf-life for foods and beverages, but also fermentation can enhance nutritional properties in a safe and effective manner. In many developed countries, traditional methods are now replaced with specific technologies for production of fermented foods, and an emerging industrial practice allows for higher quality standardization of food products in the market place. Due to changes in fermentation processes and the increased consumption of these products, a detailed review of recent patents involving fermented foods and beverages and their impact on health is warranted. Fermented food products that can enhance nutrition, improve health, and prevent disease on a global level will require consistent fermentation methods, evaluation of nutritional compositions, and food safety testing. This review is intended to guide the development of fermented foods for enhanced human health benefits and suggests the need for multidisciplinary collaborations and structural analysis across the fields of food science, microbiology, human nutrition, and biomedical sciences. PMID:22702745

Fermented Nut-Based Vegan Food: Characterization of a Home made Product and Scale-Up to an Industrial Pilot-Scale Production.

PubMed

Tabanelli, Giulia; Pasini, Federica; Riciputi, Ylenia; Vannini, Lucia; Gozzi, Giorgia; Balestra, Federica; Caboni, Maria Fiorenza; Gardini, Fausto; Montanari, Chiara

2018-03-01

Because of the impossibility to consume food of animal origin, vegan consumers are looking for substitutes that could enrich their diet. Among many substitutes, fermented nut products are made from different nut types and obtained after soaking, grinding, and fermentation. Although other fermented vegetable products have been deeply investigated, there are few data about the fermentative processes of nut-based products and the microbial consortia able to colonize these products are not yet studied. This study characterized a hand-made vegan product obtained from cashew nut. Lactic acid bacteria responsible for fermentation were identified, revealing a succession of hetero- and homo-fermentative species during process. Successively, some lactic acid bacteria isolates from the home-made vegan product were used for a pilot-scale fermentation. The products obtained were characterized and showed features similar to the home-made one, although the microbiological hazards have been prevented through proper and rapid acidification, enhancing their safety features. Spontaneous fermented products are valuable sources of microorganisms that can be used in many food processes as starter cultures. The lactic acid bacteria isolated in this research can be exploited by industries to develop new foods and therefore to enter new markets. The use of selected starter cultures guarantees good organoleptic characteristics and food safety (no growth of pathogens). © 2018 Institute of Food Technologists®.

Hydrogel Film-Immobilized Lactobacillus brevis RK03 for γ-Aminobutyric Acid Production

PubMed Central

Hsueh, Yi-Huang; Liaw, Wen-Chang; Kuo, Jen-Min; Deng, Chi-Shin

2017-01-01

Hydrogels of 2-hydroxyethyl methacrylate/polyethylene glycol diacrylate (HEMA/PEGDA) have been extensively studied for their use in biomedical and pharmaceutical applications owing to their nontoxic and highly hydrophilic characteristics. Recently, cells immobilized by HEMA/PEGDA hydrogels have also been studied for enhanced production in fermentation. Hydrogel films of HEMA/PEGDA copolymer were generated by Ultraviolet (UV)-initiated photopolymerization. The hydrogel films were used to immobilize viable Lactobacillus brevis RK03 cells for the bioconversion of monosodium glutamate (MSG) to γ-aminobutyric acid (GABA). The mechanical properties and fermentation yields of the L. brevis RK03 cells immobilized on polyacrylate hydrogel films with different monomeric formulations were investigated. Fermentation was carried out in 75 mL de Man, Rogosa and Sharpe (MRS) medium containing various concentrations of MSG. We found that HEMA (93%)/PEGDA (3%) hydrogels (sample H) maximized GABA production. The conversion rate of MSG to GABA reached a maximum value of 98.4% after 240 h. Bioconversion activity gradually declined after 420 h to 83.8% after five cycles of semi-continuous fermentation. Our results suggest that HEMA (93%)/PEGDA (3%) hydrogels have great potential for use in GABA production via semi-continuous fermentation. PMID:29099794

Propionic acid production from corn stover hydrolysate by Propionibacterium acidipropionici

DOE PAGES

Wang, Xiaoqing; Salvachua, Davinia; Sanchez i Nogue, Violeta; ...

2017-08-17

The production of value-added chemicals alongside biofuels from lignocellulosic hydrolysates is critical for developing economically viable biorefineries. Here, the production of propionic acid (PA), a potential building block for C3-based chemicals, from corn stover hydrolysate is investigated using the native PA-producing bacterium Propionibacterium acidipropionici. A wide range of culture conditions and process parameters were examined and experimentally optimized to maximize titer, rate, and yield of PA. The effect of gas sparging during fermentation was first examined, and N 2 was found to exhibit improved performance over CO 2. Subsequently, the effects of different hydrolysate concentrations, nitrogen sources, and neutralization agentsmore » were investigated. One of the best combinations found during batch experiments used yeast extract (YE) as the primary nitrogen source and NH 4OH for pH control. This combination enabled PA titers of 30.8 g/L with a productivity of 0.40 g/L h from 76.8 g/L biomass sugars, while successfully minimizing lactic acid production. Due to the economic significance of downstream separations, increasing titers using fed-batch fermentation was examined by changing both feeding media and strategy. Continuous feeding of hydrolysate was found to be superior to pulsed feeding and combined with high YE concentrations increased PA titers to 62.7 g/L and improved the simultaneous utilization of different biomass sugars. Additionally, applying high YE supplementation maintains the lactic acid concentration below 4 g/L for the duration of the fermentation. Finally, with the aim of increasing productivity, high cell density fed-batch fermentations were conducted. PA titers increased to 64.7 g/L with a productivity of 2.35 g/L h for the batch stage and 0.77 g/L h for the overall process. These results highlight the importance of media and fermentation strategy to improve PA production. Altogether, this work demonstrates the feasibility of producing PA from corn stover hydrolysate.« less

Propionic acid production from corn stover hydrolysate by Propionibacterium acidipropionici

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

Wang, Xiaoqing; Salvachua, Davinia; Sanchez i Nogue, Violeta

The production of value-added chemicals alongside biofuels from lignocellulosic hydrolysates is critical for developing economically viable biorefineries. Here, the production of propionic acid (PA), a potential building block for C3-based chemicals, from corn stover hydrolysate is investigated using the native PA-producing bacterium Propionibacterium acidipropionici. A wide range of culture conditions and process parameters were examined and experimentally optimized to maximize titer, rate, and yield of PA. The effect of gas sparging during fermentation was first examined, and N 2 was found to exhibit improved performance over CO 2. Subsequently, the effects of different hydrolysate concentrations, nitrogen sources, and neutralization agentsmore » were investigated. One of the best combinations found during batch experiments used yeast extract (YE) as the primary nitrogen source and NH 4OH for pH control. This combination enabled PA titers of 30.8 g/L with a productivity of 0.40 g/L h from 76.8 g/L biomass sugars, while successfully minimizing lactic acid production. Due to the economic significance of downstream separations, increasing titers using fed-batch fermentation was examined by changing both feeding media and strategy. Continuous feeding of hydrolysate was found to be superior to pulsed feeding and combined with high YE concentrations increased PA titers to 62.7 g/L and improved the simultaneous utilization of different biomass sugars. Additionally, applying high YE supplementation maintains the lactic acid concentration below 4 g/L for the duration of the fermentation. Finally, with the aim of increasing productivity, high cell density fed-batch fermentations were conducted. PA titers increased to 64.7 g/L with a productivity of 2.35 g/L h for the batch stage and 0.77 g/L h for the overall process. These results highlight the importance of media and fermentation strategy to improve PA production. Altogether, this work demonstrates the feasibility of producing PA from corn stover hydrolysate.« less

Quality of cucumbers commercially fermented in calcium chloride brine without sodium salts

USDA-ARS?s Scientific Manuscript database

Commercial cucumber fermentation produces large volumes of salty wastewater. This study evaluated the quality of fermented cucumbers produced commercially using an alternative calcium chloride brining process. Fermentation conducted in calcium brines (0.1M calcium chloride, 6mM potassium sorbate, eq...

The microbial fermentation characteristics depend on both carbohydrate source and heat processing: a model experiment with ileo-cannulated pigs.

PubMed

Nielsen, Tina Skau; Jørgensen, Henry; Knudsen, Knud Erik Bach; Lærke, Helle Nygaard

2017-11-01

The effects of carbohydrate (CHO) source and processing (extrusion cooking) on large intestinal fermentation products were studied in ileo-cannulated pigs as a model for humans. Pigs were fed diets containing barley, pea or a mixture of potato starch:wheat bran (PSWB) either raw or extrusion cooked. Extrusion cooking reduced the amount of starch fermented in the large intestine by 52-96% depending on the CHO source and the total pool of butyrate in the distal small intestine + large intestine by on average 60% across diets. Overall, extrusion cooking caused a shift in the composition of short-chain fatty acids (SCFA) produced towards more acetate and less propionate and butyrate. The CHO source and processing highly affected the fermentation characteristics and extrusion cooking generally reduced large intestinal fermentation and resulted in a less desirable composition of the fermentation products. The latter outcome is non-conducive to a healthy large intestinal environment and its resulting metabolic health.

Biomass, strain engineering, and fermentation processes for butanol production by solventogenic clostridia.

PubMed

Lee, Sang-Hyun; Yun, Eun Ju; Kim, Jungyeon; Lee, Sang Jun; Um, Youngsoon; Kim, Kyoung Heon

2016-10-01

Butanol is considered an attractive biofuel and a commercially important bulk chemical. However, economical production of butanol by solventogenic clostridia, e.g., via fermentative production of acetone-butanol-ethanol (ABE), is hampered by low fermentation performance, mainly as a result of toxicity of butanol to microorganisms and high substrate costs. Recently, sugars from marine macroalgae and syngas were recognized as potent carbon sources in biomass feedstocks that are abundant and do not compete for arable land with edible crops. With the aid of systems metabolic engineering, many researchers have developed clostridial strains with improved performance on fermentation of these substrates. Alternatively, fermentation strategies integrated with butanol recovery processes such as adsorption, gas stripping, liquid-liquid extraction, and pervaporation have been designed to increase the overall titer of butanol and volumetric productivity. Nevertheless, for economically feasible production of butanol, innovative strategies based on recent research should be implemented. This review describes and discusses recent advances in the development of biomass feedstocks, microbial strains, and fermentation processes for butanol production.

Alcohol

MedlinePlus

... created when grains, fruits, or vegetables are fermented . Fermentation is a process that uses yeast or bacteria ... change the sugars in the food into alcohol. Fermentation is used to produce many necessary items — everything ...

Availability of Essential B-Group Vitamins to Lactobacillus plantarum in Green Olive Fermentation Brines

PubMed Central

Ruiz-Barba, J. L.; Jimenez-Diaz, R.

1995-01-01

The availability throughout the traditional Spanish-style green olive fermentation of four vitamins that are essential for the growth of Lactobacillus plantarum was studied. It was found that nicotinic and pantothenic acids, biotin, and vitamin B(inf6) were available in the fermentation brines within the first few days of the process, and their levels throughout the fermentative process were well above those required by L. plantarum to grow at its maximum growth rate. In laboratory medium, various yeast strains isolated from the fermentations were found to produce these vitamins in amounts several times that required by L. plantarum. This finding suggests that some yeast species might play a role in encouraging the growth of L. plantarum in Spanish-style green olive fermentation. PMID:16534988

High solid fed-batch butanol fermentation with simultaneous product recovery: part II - process integration.

USDA-ARS?s Scientific Manuscript database

In these studies liquid hot water (LHW) pretreated and enzymatically hydrolyzed Sweet Sorghum Bagasse (SSB) hydrolyzates were fermented in a fed-batch reactor. As reported in the preceding paper, the culture was not able to ferment the hydrolyzate I in a batch process due to presence of high level o...

Manufacturing Ethyl Acetate From Fermentation Ethanol

NASA Technical Reports Server (NTRS)

Rohatgi, Naresh K.; Ingham, John D.

1991-01-01

Conceptual process uses dilute product of fermentation instead of concentrated ethanol. Low-concentration ethanol, extracted by vacuum from fermentation tank, and acetic acid constitutes feedstock for catalytic reaction. Product of reaction goes through steps that increases ethyl acetate content to 93 percent by weight. To conserve energy, heat exchangers recycle waste heat to preheat process streams at various points.

New challenges and opportunities for industrial biotechnology

PubMed Central

2012-01-01

Industrial biotechnology has not developed as fast as expected due to some challenges including the emergences of alternative energy sources, especially shale gas, natural gas hydrate (or gas hydrate) and sand oil et al. The weaknesses of microbial or enzymatic processes compared with the chemical processing also make industrial biotech products less competitive with the chemical ones. However, many opportunities are still there if industrial biotech processes can be as similar as the chemical ones. Taking advantages of the molecular biology and synthetic biology methods as well as changing process patterns, we can develop bioprocesses as competitive as chemical ones, these including the minimized cells, open and continuous fermentation processes et al. PMID:22905695

Investigation of Municipal Solid Waste to Alcohol Conversion for Army Use

DTIC Science & Technology

1992-03-01

fuel ethanol and other byproducts. To convert the cellulosic fraction of MSW to fermentable sugars, the first process uses a single stage of dilute acid...ethanol and other byproducts. To convert the cellulosic fraction of MSW to fermentable sugars, the first process uses a single stage of dilute acid...of the cellulosic fraction to produce fermentable sugars. The first process, developed by the Tennessee Valley Authority (TVA), employs a single

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

PubMed

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

2014-09-01

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

Eosinophilic Disorders Glossary

MedlinePlus

... and related foods may lead to bloating from fermentation of a certain carbohydrate that is high in ... and is fermented by bacteria. Byproducts of the fermentation process cause symptoms, including gas, diarrhea, nausea, and ...

A Hybrid Catalytic Route to Fuels from Biomass Syngas

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

Harmon, Laurel; Hallen, Richard; Lilga, Michael

LanzaTech partnered with the Pacific Northwest National Laboratory (PNNL), Imperium Aviation Fuels, InEnTec, Orochem Technologies, the University of Delaware, Michigan Technological University, the National Renewable Energy Laboratory, and The Boeing Company, to develop a cost-effective hybrid conversion technology for catalytic upgrading of biomass-derived syngas to sustainable alternative jet fuel (SAJF) meeting the price, quality and environmental requirements of the aviation industry. Alternative “synthetic paraffinic kerosene” (SPK) blendstock produced from syngas via “Fischer-Tropsch” (F-T) or from lipids via “hydroprocessing of esters and fatty acids” (HEFA) are currently being used in commercial jet fuel blends containing at least 50% petroleum-based fuel. Thismore » project developed an alternative route to SAJF from ethanol, a type of “alcohol to jet” (ATJ) SPK. The project objective was to demonstrate a pathway that combines syngas fermentation to ethanol with catalytic upgrading of ethanol to sustainable alternative jet fuel and shows attractive overall system economics to drive down the price of biomass-derived jet fuel. The hybrid pathway was to be demonstrated on three biomass feedstocks: corn stover, woody biomass, and third biomass feedstock, cellulosic residues. The objective also included the co-production of chemicals, exemplified by 2,3-Butanediol (2,3-BDO), which can be converted to key chemical intermediates. The team successfully demonstrated that biomass syngas fermentation followed by catalytic conversion is a viable alternative to the Fischer-Tropsch process and produces a fuel with properties comparable to F-T and HEFA SPKs. Plasma gasification and gas fermentation were successfully integrated and demonstrated in continuous fermentations on waste wood, corn stover, and cellulosic bagasse. Gas fermentation was demonstrated to produce ethanol suitable for catalytic upgrading, isolating the upgrading from variations in biomass feed, syngas composition, and impurities. Ethanol feedstocks from all three types of biomass were demonstrated to be comparable to grain derived ethanol and suitable for the LT-PNNL ATJ process. The LT-PNNL ATJ catalytic upgrading process was demonstrated at lab scale for over 2000 hours of continuous operation on a single catalyst load. LanzaTech scaled up the ATJ process, producing 4000 gallons of jet and 600 gallons of diesel for testing and a future proving flight. The LT-PNNL ATJ process, at lab and pilot scale, using commercial grain-based ethanol and steel mill waste gas-based ethanol (“Lanzanol”), produces high-quality fuel-range distillates containing primarily normal paraffins and isoparaffins. The LT-PNNL ATJ fuel has equivalent properties to previously-approved SPKs such as F-T, HEFA, and ATJ from isobutanol, and conforms with critical properties needed to blend with conventional jet fuel. The project showed that the 2,3-BDO fermentation co-product can be separated economically utilizing Simulated Moving Bed (SMB) technology. 2,3-BDO can be catalytically converted to 1,3-butadiene (BD) in a two-step process with at least 70% yield, producing a chemical intermediate suitable for downstream applications. Technoeconomic and life cycle analyses of the biomass to jet process with and without 2,3-BDO production showed that capital costs are sensitive to the proportion of the 2,3-BDO co-product and biomass feedstock. The co-product 2,3-BDO, converted through to BD, significantly reduces the cash cost of production of the hydrocarbon fuels. Life cycle GHG emissions of ATJ SPK produced from biomass using a steam gasification system are projected to be significantly lower than those of conventional jet fuel. The project demonstrated that a high quality ATJ SPK, can be produced from biomass via a hybrid gas fermentation/catalytic route. Validation of the LT-PNNL ATJ process using a variety of ethanol feedstocks demonstrated the viability of a future model of distributed ATJ production, in which ethanol may be produced at multiple facilities from local feedstocks and shipped to a central facility for conversion. The project demonstrated that co-production of chemicals has the potential to reduce jet cost of production, thereby accelerating commercial production of SAJF from biomass.« less

Effects of pre-fermentation and pulsed-electric-field treatment of primary sludge in microbial electrochemical cells.

PubMed

Ki, Dongwon; Parameswaran, Prathap; Popat, Sudeep C; Rittmann, Bruce E; Torres, César I

2015-11-01

The aim of this study was to investigate the combination of two technologies - pulsed electric field (PEF) pre-treatment and semi-continuous pre-fermentation of primary sludge (PS) - to produce volatile fatty acids (VFAs) as the electron donor for microbial electrolysis cells (MECs). Pre-fermentation with a 3-day solids retention time (SRT) led to the maximum generation of VFAs, with or without pretreatment of the PS through pulsed-electric-fields (PEF). PEF treatment before fermentation enhanced the accumulation of the preferred VFA, acetate, by 2.6-fold. Correspondingly, MEC anodes fed with centrate from 3-day pre-fermentation of PEF-treated PS had a maximum current density ∼3.1 A/m(2), which was 2.4-fold greater than the control pre-fermented centrate. Over the full duration of batch MEC experiments, using pre-fermented centrate led to successful performance in terms of Coulombic efficiency (95%), Coulombic recovery (80%), and COD-removal efficiency (85%). Copyright © 2015 Elsevier Ltd. All rights reserved.

Health benefits of fermented foods.

PubMed

Şanlier, Nevin; Gökcen, Büşra Başar; Sezgin, Aybüke Ceyhun

2017-09-25

In the past, the beneficial effects of fermented foods on health were unknown, and so people primarily used fermentation to preserve foods, enhance shelf life, and improve flavour. Fermented foods became an important part of the diet in many cultures, and over time fermentation has been associated with many health benefits. Because of this, the fermentation process and the resulting fermented products have recently attracted scientific interest. In addition, microorganisms contributing to the fermentation process have recently been associated with many health benefits, and so these microorganisms have become another focus of attention. Lactic acid bacteria (LAB) have been some of the most studied microorganisms. During fermentation, these bacteria synthesize vitamins and minerals, produce biologically active peptides with enzymes such as proteinase and peptidase, and remove some non-nutrients. Compounds known as biologically active peptides, which are produced by the bacteria responsible for fermentation, are also well known for their health benefits. Among these peptides, conjugated linoleic acids (CLA) have a blood pressure lowering effect, exopolysaccharides exhibit prebiotic properties, bacteriocins show anti-microbial effects, sphingolipids have anti-carcinogenic and anti-microbial properties, and bioactive peptides exhibit anti-oxidant, anti-microbial, opioid antagonist, anti-allergenic, and blood pressure lowering effects. As a result, fermented foods provide many health benefits such as anti-oxidant, anti-microbial, anti-fungal, anti-inflammatory, anti-diabetic and anti-atherosclerotic activity. However, some studies have shown no relationship between fermented foods and health benefits. Therefore, this paper aims to investigate the health effects of fermented foods.

Operational strategies, monitoring and control of heterologous protein production in the methylotrophic yeast Pichia pastoris under different promoters: A review

PubMed Central

Cos, Oriol; Ramón, Ramón; Montesinos, José Luis; Valero, Francisco

2006-01-01

The methylotrophic yeast Pichia pastoris has been widely reported as a suitable expression system for heterologous protein production. The use of different phenotypes under PAOX promoter, other alternative promoters, culture medium, and operational strategies with the objective to maximize either yield or productivity of the heterologous protein, but also to obtain a repetitive product batch to batch to get a robust process for the final industrial application have been reported. Medium composition, kinetics growth, fermentation operational strategies from fed-batch to continuous cultures using different phenotypes with the most common PAOX promoter and other novel promoters (GAP, FLD, ICL), the use of mixed substrates, on-line monitoring of the key fermentation parameters (methanol) and control algorithms applied to the bioprocess are reviewed and discussed in detail. PMID:16600031

Neural network processing of microbial fuel cell signals for the identification of chemicals present in water.

PubMed

Feng, Yinghua; Barr, William; Harper, W F

2013-05-15

Biosensing is emerging as an important element of water quality monitoring. This research demonstrated that microbial fuel cell (MFC)-based biosensing can be integrated with artificial neural networks (ANNs) to identify specific chemicals present in water samples. The non-fermentable substrates, acetate and butyrate, induced peak areas (PA) and peak heights (PH) that were generally larger than those caused by the injection of fermentable substrates, glucose and corn starch. The ANN successfully identified peaks associated with these four chemicals under a variety of experimental conditions and for two MFCs that had different levels of sensitivity. ANNs that employ the hyperbolic tangent sigmoid transfer function performed better than those using non-continuous transfer functions. ANNs should be integrated into water quality monitoring efforts for smart biosensing. Published by Elsevier Ltd.

Investigation of the instability and low water kefir grain growth during an industrial water kefir fermentation process.

PubMed

Laureys, David; Van Jean, Amandine; Dumont, Jean; De Vuyst, Luc

2017-04-01

A poorly performing industrial water kefir production process consisting of a first fermentation process, a rest period at low temperature, and a second fermentation process was characterized to elucidate the causes of its low water kefir grain growth and instability. The frozen-stored water kefir grain inoculum was thawed and reactivated during three consecutive prefermentations before the water kefir production process was started. Freezing and thawing damaged the water kefir grains irreversibly, as their structure did not restore during the prefermentations nor the production process. The viable counts of the lactic acid bacteria and yeasts on the water kefir grains and in the liquors were as expected, whereas those of the acetic acid bacteria were high, due to the aerobic fermentation conditions. Nevertheless, the fermentations progressed slowly, which was caused by excessive substrate concentrations resulting in a high osmotic stress. Lactobacillus nagelii, Lactobacillus paracasei, Lactobacillus hilgardii, Leuconostoc mesenteroides, Bifidobacterium aquikefiri, Gluconobacter roseus/oxydans, Gluconobacter cerinus, Saccharomyces cerevisiae, and Zygotorulaspora florentina were the most prevalent microorganisms. Lb. hilgardii, the microorganism thought to be responsible for water kefir grain growth, was not found culture-dependently, which could explain the low water kefir grain growth of this industrial process.

Optimization of prehydrolysis time and substrate feeding to improve ethanol production by simultaneous saccharification and fermentation of furfural process residue.

PubMed

He, Jianlong; Zhang, Wenbo; Liu, Xiaoyan; Xu, Ning; Xiong, Peng

2016-11-01

Ethanol is a very important industrial chemical. In order to improve ethanol productivity using Saccharomyces cerevisiae in fermentation from furfural process residue, we developed a process of simultaneous saccharification and fermentation (SSF) of furfural process residue, optimizing prehydrolysis cellulase loading concentration, prehydrolysis time, and substrate feeding strategy. The ethanol concentration obtained from the optimized process was 19.3 g/L, corresponding 76.5% ethanol yield, achieved by running SSF for 48 h from 10% furfural process residue with prehydrolysis at 50°C for 4 h and cellulase loading of 15 FPU/g furfural process residue. For higher ethanol concentrations, fed-batch fermentation was performed. The optimized fed-batch process increased the ethanol concentration to 37.6 g/L, 74.5% yield, obtained from 10% furfural process residue with two additions of 5% substrate at 12 and 24 h. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

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

PubMed

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

2014-08-01

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

Characterisation of the microbiota of rice sourdoughs and description of Lactobacillus spicheri sp. nov.

PubMed

Meroth, Christiane B; Hammes, Walter P; Hertel, Christian

2004-03-01

The microbiota of two industrially processed rice sourdoughs was characterised by bacteriological culture in combination with PCR-denaturing gradient gel electrophoresis (DGGE) and 16S/28S rDNA sequence analysis. Rice sourdough I was continuously propagated for several years by back-slopping every week, whereas sourdough II was processed by using a commercial starter culture and back-slopping daily for three days. In rice sourdough II Candida krusei and Saccharomyces cerevisiae as well as Lactobacillus fermentum, Lactobacillus gallinarum, Lactobacillus kimchii, Lactobacillus plantarum, and Lactobacillus pontis dominated at the first day of fermentation. RAPD analysis of lactobacilli revealed identical profiles for each of the species except for L. fermentum and L. pontis indicating the presence of different strains. Fluctuations within the LAB community during fermentation were monitored by PCR-DGGE. L. pontis decreased in numbers over time and L. curvatus became dominant after 3 days of fermentation. Rice sourdough I contained S. cerevisiae, Lactobacillus paracasei (present with three different RAPD types), Lactobacillus paralimentarius, and a Lactobacillus strain which could not be allotted to any valid species. Phylogenetic analysis based on 16S rDNA sequences revealed Lactobacillus brevis as the closest relative (97.3% sequence similarity). Differences in some phenotypic characteristics and DNA-DNA relatedness indicated that the strain represents a new Lactobacillus species, for which the name Lactobacillus spicheri is proposed.

Industrial yogurt manufacture: monitoring of fermentation process and improvement of final product quality.

PubMed

Soukoulis, C; Panagiotidis, P; Koureli, R; Tzia, C

2007-06-01

Lactic acid fermentation during the production of skim milk and whole fat set-style yogurt was continuously monitored by measuring pH. The modified Gompertz model was successfully applied to describe the pH decline and viscosity development during the fermentation process. The viscosity and incubation time data were also fitted to linear models against ln(pH). The investigation of the yogurt quality improvement practices included 2 different heat treatments (80 degrees C for 30 min and 95 degrees C for 10 min), 3 milk protein fortifying agents (skim milk powder, whey powder, and milk protein concentrate) added at 2.0%, and 4 hydrocolloids (kappa-carrageenan, xanthan, guar gum, and pectin) added at 0.01% to whole fat and skim yogurts. Heat treatment significantly affected viscosity and acetaldehyde development without influencing incubation time and acidity. The addition of whey powder shortened the incubation time but had a detrimental effect on consistency, firmness, and overall acceptance of yogurts. On the other hand, addition of skim milk powder improved the textural quality and decreased the vulnerability of yogurts to syneresis. Anionic stabilizers (kappa-carrageenan and pectin) had a poor effect on the texture and palatability of yogurts. However, neutral gums (xanthan and guar gum) improved texture and prevented the wheying-off defect. Skim milk yogurts exhibited longer incubation times and higher viscosities, whereas they were rated higher during sensory evaluation than whole fat yogurts.

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

PubMed

Arrizon, J; Gschaedler, A

2007-04-01

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

Studying the rapid bioconversion of lignocellulosic sugars into ethanol using high cell density fermentations with cell recycle

PubMed Central

2014-01-01

Background The Rapid Bioconversion with Integrated recycle Technology (RaBIT) process reduces capital costs, processing times, and biocatalyst cost for biochemical conversion of cellulosic biomass to biofuels by reducing total bioprocessing time (enzymatic hydrolysis plus fermentation) to 48 h, increasing biofuel productivity (g/L/h) twofold, and recycling biocatalysts (enzymes and microbes) to the next cycle. To achieve these results, RaBIT utilizes 24-h high cell density fermentations along with cell recycling to solve the slow/incomplete xylose fermentation issue, which is critical for lignocellulosic biofuel fermentations. Previous studies utilizing similar fermentation conditions showed a decrease in xylose consumption when recycling cells into the next fermentation cycle. Eliminating this decrease is critical for RaBIT process effectiveness for high cycle counts. Results Nine different engineered microbial strains (including Saccharomyces cerevisiae strains, Scheffersomyces (Pichia) stipitis strains, Zymomonas mobilis 8b, and Escherichia coli KO11) were tested under RaBIT platform fermentations to determine their suitability for this platform. Fermentation conditions were then optimized for S. cerevisiae GLBRCY128. Three different nutrient sources (corn steep liquor, yeast extract, and wheat germ) were evaluated to improve xylose consumption by recycled cells. Capacitance readings were used to accurately measure viable cell mass profiles over five cycles. Conclusion The results showed that not all strains are capable of effectively performing the RaBIT process. Acceptable performance is largely correlated to the specific xylose consumption rate. Corn steep liquor was found to reduce the deleterious impacts of cell recycle and improve specific xylose consumption rates. The viable cell mass profiles indicated that reduction in specific xylose consumption rate, not a drop in viable cell mass, was the main cause for decreasing xylose consumption. PMID:24847379

Foods That May Cause Gas

MedlinePlus

... intact. In the colon, certain bacteria digest fiber (fermentation), which produces gas. Dietary fiber can be classified ... the GI tract, and in the process of fermentation. The solubility and fermentation of a particular fiber ...

Fermentation and recovery process for lactic acid production

DOEpatents

Tsai, S.P.; Moon, S.H.; Coleman, R.

1995-11-07

A method is described for converting starch to glucose and fermenting glucose to lactic acid, including simultaneous saccharification and fermentation through use of a novel consortium of bacterial strains. 2 figs.

Methane fermentation process for utilization of organic waste

NASA Astrophysics Data System (ADS)

Frąc, M.; Ziemiński, K.

2012-07-01

Biogas is a renewable and sustainable energy carrier generated via anaerobic digestion of biomass. This fuel is derived from various biomass resources and depending on its origin it contains methane (40-75%), carbon dioxide (20-45%) and some other compounds. The aim of this paper is to present the current knowledge and prospects of using the methane fermentation process to dispose of various types of organic wastes as well as conditions and factors affecting the methane fermentation process.

Impact of an acid fungal protease in high gravity fermentation for ethanol production using Indian sorghum as a feedstock.

PubMed

Gohel, V; Duan, G; Maisuria, V B

2013-01-01

This study evaluated the conventional jet cooking liquefaction process followed by simultaneous saccharification and fermentation (SSF) at 30% and 35% dry solids (DS) concentration of Indian sorghum feedstock for ethanol production, with addition of acid fungal protease or urea. To evaluate the efficacy of thermostable α-amylase in liquefaction at 30% and 35% DS concentration of Indian sorghum, liquefact solubility, higher dextrins, and fermentable sugars were analyzed at the end of the process. The liquefact was further subjected to SSF using yeast. In comparison with urea, addition of an acid fungal protease during SSF process was observed to accelerate yeast growth (μ), substrate consumption (Q(s)), ultimately ethanol yield based on substrate (Y(p/s)) and ethanol productivity based on fermentation time (Q(p)). The fermentation efficiency and ethanol recovery were determined for both concentrations of Indian sorghum and found to be increased with use of acid fungal protease in SSF process. Copyright © 2013 American Institute of Chemical Engineers.

Beer fermentation: monitoring of process parameters by FT-NIR and multivariate data analysis.

PubMed

Grassi, Silvia; Amigo, José Manuel; Lyndgaard, Christian Bøge; Foschino, Roberto; Casiraghi, Ernestina

2014-07-15

This work investigates the capability of Fourier-Transform near infrared (FT-NIR) spectroscopy to monitor and assess process parameters in beer fermentation at different operative conditions. For this purpose, the fermentation of wort with two different yeast strains and at different temperatures was monitored for nine days by FT-NIR. To correlate the collected spectra with °Brix, pH and biomass, different multivariate data methodologies were applied. Principal component analysis (PCA), partial least squares (PLS) and locally weighted regression (LWR) were used to assess the relationship between FT-NIR spectra and the abovementioned process parameters that define the beer fermentation. The accuracy and robustness of the obtained results clearly show the suitability of FT-NIR spectroscopy, combined with multivariate data analysis, to be used as a quality control tool in the beer fermentation process. FT-NIR spectroscopy, when combined with LWR, demonstrates to be a perfectly suitable quantitative method to be implemented in the production of beer. Copyright © 2014 Elsevier Ltd. All rights reserved.

Suitability of anaerobic digestion effluent as process water for corn fuel ethanol fermentation.

PubMed

Wang, Ke; Zhang, Jian-Hua; Liu, Pei; Mao, Zhong-Gui

2014-01-01

A corn fuel ethanol plant integrated with anaerobic digestion treatment of thin stillage increases the net energy balance. Furthermore, the anaerobic digestion effluent (ADE) can be reused as a potential substitute for process water in the ethanol fermentation. In this study, the suitability of ADE as process water for corn ethanol fermentation was investigated by analyzing the potential inhibitory components in the ADE. It was found that ammonium influenced the growth and metabolism of Saccharomyces cerevisiae. Maximum ethanol production was obtained when the concentration of ammonium nitrogen was 200 mg/L, and ammonium could replace urea as the nitrogen source for S. cerevisiae under this concentration. In the ethanol fermentation with a higher concentration of ammonium, more glycerol was produced, thereby resulting in the decrease of ethanol production. In addition, components except ammonium in the ADE caused no inhibition to ethanol production. These results suggest that ADE could be reused as process water for corn ethanol fermentation without negative effect when ammonium concentration is well controlled.

L-Methionine Production.

PubMed

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

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

[Transformation of baicalin and wogonoside through liquid fermentation with Bacillus natto].

PubMed

Long, Hou-ning; Zhang, Shuo; Yao, Lei; Zhang, Min; Wang, Peng-jiao; Meng, Xiao-xia; Gao, Xiu; Zhang, Rong-ping

2015-12-01

This experiment aimed to explore and research the process of preparing baicalein and wogonin through liquid fermentation with Bacillus natto. Active enzymes of produced by B. natto was used for the biological transformation of baclin and wogonoside, in order to increase the content of the haicalein and wogonin in the scutellaria. With the content of the baicalein and wogonin as evaluating indexes, the effects of carbon source, nitrogen source, the types and suitable concentration of inorganic salt, medium pH, granularities of medical materials, liquid volume in flask, shaking speed, liquid-to-solid ratio, fermentation time on the fermentation process were studied. The optimal process conditions for liquid fermentation of scutellaria were 1.0% of peptone, 0.05% of NaCl, pH at 6, the granularities of medical materials of the scutellaria screened through 40-mesh sifter, 33% of liquid, shaker incubator speed at 200 r x min(-1), liquid-to-solid ratio of 5:1, temperature at 37 degrees C, fermentation for 6 days, baclin's conversion rate at 97.6% and wogonoside's conversion rate at 97% in the scutellaria. According to the verification test, the process was stable and feasible, and could provide data reference for the industrial production.

From Vineyard Soil to Wine Fermentation: Microbiome Approximations to Explain the “terroir” Concept

PubMed Central

Belda, Ignacio; Zarraonaindia, Iratxe; Perisin, Matthew; Palacios, Antonio; Acedo, Alberto

2017-01-01

Wine originally emerged as a serendipitous mix of chemistry and biology, where microorganisms played a decisive role. From these ancient fermentations to the current monitored industrial processes, winegrowers and winemakers have been continuously changing their practices according to scientific knowledge and advances. A new enology direction is emerging and aiming to blend the complexity of spontaneous fermentations with industrial safety of monitored fermentations. In this context, wines with distinctive autochthonous peculiarities have a great acceptance among consumers, causing important economic returns. The concept of terroir, far from being a rural term, conceals a wide range of analytical parameters that are the basis of the knowledge-based enology trend. In this sense, the biological aspect of soils has been underestimated for years, when actually it contains a great microbial diversity. This soil-associated microbiota has been described as determinant, not only for the chemistry and nutritional properties of soils, but also for health, yield, and quality of the grapevine. Additionally, recent works describe the soil microbiome as the reservoir of the grapevine associated microbiota, and as a contributor to the final sensory properties of wines. To understand the crucial roles of microorganisms on the entire wine making process, we must understand their ecological niches, population dynamics, and relationships between ‘microbiome- vine health’ and ‘microbiome-wine metabolome.’ These are critical steps for designing precision enology practices. For that purpose, current metagenomic techniques are expanding from laboratories, to the food industry. This review focuses on the current knowledge about vine and wine microbiomes, with emphasis on their biological roles and the technical basis of next-generation sequencing pipelines. An overview of molecular and informatics tools is included and new directions are proposed, highlighting the importance of –omics technologies in wine research and industry. PMID:28533770

Continuous monitoring of dough fermentation and bread baking by magnetic resonance microscopy.

PubMed

Bajd, Franci; Serša, Igor

2011-04-01

The consumer quality of baked products is closely related with dough structure properties. These are developed during dough fermentation and finalized during its baking. In this study, magnetic resonance microscopy (MRM) was employed in a study of dough fermentation and baking. A small hot air oven was installed inside a 2.35-T horizontal bore superconducting magnet. Four different samples of commercial bread mixes for home baking were used to prepare small samples of dough that were inserted in the oven and allowed to rise at 33 °C for 112 min; this was followed by baking at 180 °C for 49 min. The entire process was followed by dynamic T(1)-weighted 3D magnetic resonance imaging with 7 min of temporal resolution and 0.23×0.23×1.5 mm(3) of spatial resolution. Acquired images were analyzed to determine time courses of dough pore distribution, dough volume and bread crust thickness. Image analysis showed that both the number of dough pores and the normalized dough volume increased in a sigmoid-like fashion during fermentation and decreased during baking due to the bread crust formation. The presented magnetic resonance method was found to be efficient in analysis of dough structure properties and in discrimination between different dough types. Copyright © 2011 Elsevier Inc. All rights reserved.

Continuous High-solids corn liquefaction and fermentation with stripping of ethanol

USDA-ARS?s Scientific Manuscript database

Removal of ethanol from the fermentor during fermentation can increase productivity and reduce the costs for dewatering the product and coproduct. One approach is to recycle the fermentor contents through a stripping column, where a non-condensable gas removes ethanol to a condenser. Previous resear...

Mathematical modeling of continuous ethanol fermentation in a membrane bioreactor by pervaporation compared to conventional system: Genetic algorithm.

PubMed

Esfahanian, Mehri; Shokuhi Rad, Ali; Khoshhal, Saeed; Najafpour, Ghasem; Asghari, Behnam

2016-07-01

In this paper, genetic algorithm was used to investigate mathematical modeling of ethanol fermentation in a continuous conventional bioreactor (CCBR) and a continuous membrane bioreactor (CMBR) by ethanol permselective polydimethylsiloxane (PDMS) membrane. A lab scale CMBR with medium glucose concentration of 100gL(-1) and Saccharomyces cerevisiae microorganism was designed and fabricated. At dilution rate of 0.14h(-1), maximum specific cell growth rate and productivity of 0.27h(-1) and 6.49gL(-1)h(-1) were respectively found in CMBR. However, at very high dilution rate, the performance of CMBR was quite similar to conventional fermentation on account of insufficient incubation time. In both systems, genetic algorithm modeling of cell growth, ethanol production and glucose concentration were conducted based on Monod and Moser kinetic models during each retention time at unsteady condition. The results showed that Moser kinetic model was more satisfactory and desirable than Monod model. Copyright © 2016 Elsevier Ltd. All rights reserved.

Encapsulation of brewing yeast in alginate/chitosan matrix: lab-scale optimization of lager beer fermentation.

PubMed

Naydenova, Vessela; Badova, Mariyana; Vassilev, Stoyan; Iliev, Vasil; Kaneva, Maria; Kostov, Georgi

2014-03-04

Two mathematical models were developed for studying the effect of main fermentation temperature ( T MF ), immobilized cell mass ( M IC ) and original wort extract (OE) on beer fermentation with alginate-chitosan microcapsules with a liquid core. During the experiments, the investigated parameters were varied in order to find the optimal conditions for beer fermentation with immobilized cells. The basic beer characteristics, i.e. extract, ethanol, biomass concentration, pH and colour, as well as the concentration of aldehydes and vicinal diketones, were measured. The results suggested that the process parameters represented a powerful tool in controlling the fermentation time. Subsequently, the optimized process parameters were used to produce beer in laboratory batch fermentation. The system productivity was also investigated and the data were used for the development of another mathematical model.

Encapsulation of brewing yeast in alginate/chitosan matrix: lab-scale optimization of lager beer fermentation

PubMed Central

Naydenova, Vessela; Badova, Mariyana; Vassilev, Stoyan; Iliev, Vasil; Kaneva, Maria; Kostov, Georgi

2014-01-01

Two mathematical models were developed for studying the effect of main fermentation temperature (T MF), immobilized cell mass (M IC) and original wort extract (OE) on beer fermentation with alginate-chitosan microcapsules with a liquid core. During the experiments, the investigated parameters were varied in order to find the optimal conditions for beer fermentation with immobilized cells. The basic beer characteristics, i.e. extract, ethanol, biomass concentration, pH and colour, as well as the concentration of aldehydes and vicinal diketones, were measured. The results suggested that the process parameters represented a powerful tool in controlling the fermentation time. Subsequently, the optimized process parameters were used to produce beer in laboratory batch fermentation. The system productivity was also investigated and the data were used for the development of another mathematical model. PMID:26019512

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

NASA Astrophysics Data System (ADS)

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

2018-03-01

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

Phenotypic selection of a wild Saccharomyces cerevisiae strain for simultaneous saccharification and co-fermentation of AFEX pretreated corn stover

Treesearch

Mingie Jin; Cory Sarks; Christa Gunawan; Benjamin D. Bice; Shane P. Simonett; Ragothaman Avanasi Narasimhan; Laura B. Willis; Bruce E. Dale; Venkatesh Balan; Trey K. Sato

2013-01-01

Simultaneous saccharification and co-fermentation (SSCF) process involves enzymatic hydrolysis of pretreated lignocellulosic biomass and fermentation of glucose and xylose in one bioreactor. The optimal temperatures for enzymatic hydrolysis are higher than the standard fermentation temperature of ethanologenic Saccharomyces cerevisiae. Moreover,...

Extractive fermentation for enhanced propionic acid production from lactose by Propionibacterium acidipropionici

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

Jin, Z.; Yang, S.T.

1998-05-01

An extractive fermentation process using an amine extractant and a hollow-fiber membrane extractor to selectively remove propionic acid from the fermentation broth was developed to produce propionate from lactose. Compared to the conventional batch fermentation, the extractive fermentation had a much higher productivity ({approximately}1 g/(L{center_dot}h) or 5-fold increase), higher propionate yield (up to 0.66 g/g or more than 20% increase), higher final product concentration (75 g/L or higher), and higher product purity ({approximately}90%). Meanwhile, acetate and succinate productions in the extractive fermentation were significantly reduced. The improved fermentation performance can be attributed to the reduced product inhibition and a possiblemore » metabolic pathway shift to favor more propionic but less acetic and succinic acid production. The process was stable and gave consistent long-term performance over the 1.5-month period studied. The effects of propionate concentration, pH, and amine content in the solvent on the extractive fermentation were also studied and are discussed in this paper.« less

System-level modeling of acetone-butanol-ethanol fermentation.

PubMed

Liao, Chen; Seo, Seung-Oh; Lu, Ting

2016-05-01

Acetone-butanol-ethanol (ABE) fermentation is a metabolic process of clostridia that produces bio-based solvents including butanol. It is enabled by an underlying metabolic reaction network and modulated by cellular gene regulation and environmental cues. Mathematical modeling has served as a valuable strategy to facilitate the understanding, characterization and optimization of this process. In this review, we highlight recent advances in system-level, quantitative modeling of ABE fermentation. We begin with an overview of integrative processes underlying the fermentation. Next we survey modeling efforts including early simple models, models with a systematic metabolic description, and those incorporating metabolism through simple gene regulation. Particular focus is given to a recent system-level model that integrates the metabolic reactions, gene regulation and environmental cues. We conclude by discussing the remaining challenges and future directions towards predictive understanding of ABE fermentation. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A grey box model of glucose fermentation and syntrophic oxidation in microbial fuel cells.

PubMed

de Los Ángeles Fernandez, Maria; de Los Ángeles Sanromán, Maria; Marks, Stanislaw; Makinia, Jacek; Gonzalez Del Campo, Araceli; Rodrigo, Manuel; Fernandez, Francisco Jesus

2016-01-01

In this work, the fermentative and oxidative processes taking place in a microbial fuel cell (MFC) fed with glucose were studied and modeled. The model accounting for the bioelectrochemical processes was based on ordinary, Monod-type differential equations. The model parameters were estimated using experimental results obtained from three H-type MFCs operated at open or closed circuits and fed with glucose or ethanol. The experimental results demonstrate that similar fermentation processes were carried out under open and closed circuit operation, with the most important fermentation products being ethanol (with a yield of 1.81molmol(-1) glucose) and lactic acid (with a yield of 1.36molmol(-1) glucose). A peak in the electricity generation was obtained when glucose and fermentation products coexisted in the liquid bulk. However, almost 90% of the electricity produced came from the oxidation of ethanol. Copyright © 2015 Elsevier Ltd. All rights reserved.

Lignocellulosic Biomass: A Sustainable Bioenergy Source for the Future.

PubMed

Fatma, Shabih; Hameed, Amir; Noman, Muhammad; Ahmed, Temoor; Shahid, Muhammad; Tariq, Mohsin; Sohail, Imran; Tabassum, Romana

2018-01-01

Increasing population and industrialization are continuously oppressing the existing energy resources and depleting the global fuel reservoirs. The elevated pollutions from the continuous consumption of non-renewable fossil fuels also seriously contaminating the surrounding environment. The use of alternate energy sources can be an environment-friendly solution to cope these challenges. Among the renewable energy sources biofuels (biomass-derived fuels) can serve as a better alternative to reduce the reliance on non-renewable fossil fuels. Bioethanol is one of the most widely consumed biofuels of today's world. The main objective of this review is to highlight the significance of lignocellulosic biomass as a potential source for the production of biofuels like bioethanol, biodiesel or biogas. We discuss the application of various methods for the bioconversion of lignocellulosic biomass to end products i.e. biofuels. The lignocellulosic biomass must be pretreated to disintegrate lignocellulosic complexes and to expose its chemical components for downstream processes. After pretreatment, the lignocellulosic biomass is then subjected to saccharification either via acidic or enzymatic hydrolysis. Thereafter, the monomeric sugars resulted from hydrolysis step are further processed into biofuel i.e. bioethanol, biodiesel or butanol etc. through the fermentation process. The fermented impure product is then purified through the distillation process to obtain pure biofuel. Renewable energy sources represent the potential fuel alternatives to overcome the global energy crises in a sustainable and eco-friendly manner. In future, biofuels may replenish the conventional non-renewable energy resources due to their renewability and several other advantages. Lignocellulosic biomass offers the most economical biomass to generate biofuels. However, extensive research is required for the commercial production of an efficient integrated biotransformation process for the production of lignocellulose mediated biofuels. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

The Effect of Fermentation and Drying on Clicanthus Nutans Lindai Extract Chemical Constituents and Bioactivity

NASA Astrophysics Data System (ADS)

Lee, Y. Y.; Teh, P. S.; Kumaresan, S.; Tiong, C. H.

2017-06-01

In this study, two processes (fermentation and drying) were conducted on Clicanthus Nutans Lindau, which is well-known for its antioxidant activities. The aim of this research is to investigate the effects of these processes towards the Total Phenolic Content (TPC), antioxidant activity and the crude yield of the leaves. For the fermentation process, the fermentation time is varied for 6, 12, 24, 48 and 72 hours. For drying, oven drying (40, 45 and 50°C, freeze-drying and shade drying are investigated. Blanching was also conducted for oven dried samples (90°C for 1 minute). It was found that 12 hours fermentation produced the highest yield corresponding to Total Phenolic Content at 0.33 while 6 hours fermentation produced the highest Antioxidant Activity and yield at 2.218 x 10-10 mg/mL and 0.64 . On the other hand, 48 hours fermentation produced the highest overall extract yield at 0.64 . Analysis for antioxidant activity was carried out using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Folin-Ciocalteau method for Total Phenolic Content. Thermal inactivation kinetics (blanching) has been investigated for oven drying samples. Results showed that 40°C oven drying and 50°C oven drying with blanching has better retention of bioactive constituents. Blanching has no significant effect on phenolic content but has increased the crude extract for higher temperature oven drying. It has no positive effect on antioxidant activity. Drying is also a better processing method compared to fermentation as drying has slightly favorable results in all three aspects. Through comparison with extraction time of 60 minutes for 40°C oven drying and 6 hour fermented samples, yield of total phenolic content and overall yield of oven dried sample is higher than fermented sample by 4.14 and 0.39 respectively as well as showing better antioxidant activity.

[Effect of excess ethanol on the growth of yeasts of the genus Candida during continuous cultivation].

PubMed

Shkidchenko, A N; Shul'ga, A V; Gurina, L V

1988-01-01

The effect of flow rates and a specific ethanol load on the growth of Candida utilis and Candida krusei was studied in the process of one-step and three-step cultivation. The productive capacity of fermenters and the economic coefficient of yeast biomass production were shown to depend on the ability of microbial populations to assimilate a certain quantity of a carbon substrate per unit time. When a specific ethanol load exceeds the optimal one, the respiratory activity of a population and the economic coefficient of growth fall down whereas the accumulation of metabolites in the cultural broth increases. The steady state of biomass can be maintained in the process of continuous cultivation by inhibiting the yeast growth with an excess of ethanol.

Immobilized anaerobic fermentation for bio-fuel production by Clostridium co-culture.

PubMed

Xu, Lei; Tschirner, Ulrike

2014-08-01

Clostridium thermocellum/Clostridium thermolacticum co-culture fermentation has been shown to be a promising way of producing ethanol from several carbohydrates. In this research, immobilization techniques using sodium alginate and alkali pretreatment were successfully applied on this co-culture to improve the bio-ethanol fermentation performance during consolidated bio-processing (CBP). The ethanol yield obtained increased by over 60 % (as a percentage of the theoretical maximum) as compared to free cell fermentation. For cellobiose under optimized conditions, the ethanol yields were approaching about 85 % of the theoretical efficiency. To examine the feasibility of this immobilization co-culture on lignocellulosic biomass conversion, untreated and pretreated aspen biomasses were also used for fermentation experiments. The immobilized co-culture shows clear benefits in bio-ethanol production in the CBP process using pretreated aspen. With a 3-h, 9 % NaOH pretreatment, the aspen powder fermentation yields approached 78 % of the maximum theoretical efficiency, which is almost twice the yield of the untreated aspen fermentation.

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

PubMed

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

2017-01-01

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

Production of ethanol from raw cassava starch by a nonconventional fermentation method

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

Ueda, S.; Zenin, C.T.; Monteiro, D.A.

Raw cassava root starch was transformed into ethanol in a one-step process of fermentation, in which are combined the conventional processes of liquefaction, saccharification, and fermentation to alcohol. Aspergillus awamori NRRL 3112 and Aspergillus niger were cultivated on wheat bran and used as Koji enzymes. Commercial A. niger amyloglucosidase was also used in this experiment. A raw cassava root homogenate-enzymes-yeast mixture fermented optimally at pH 3.5 and 30/degree/C, for five days and produced ethanol. Alcohol yields from raw cassava roots were between 82.3 and 99.6%. Fungal Koji enzymes effectively decreased the viscosity of cassava root fermentation mashes during incubation. Commercialmore » A. niger amyloglucosidase decreased the viscosity slightly. Reduction of viscosity of fermentation mashes was 40, 84, and 93% by commercial amyloglucosidase, A. awamori, and A. niger enzymes, respectively. The reduction of viscosity of fermentation mashes is probably due to the hydrolysis of pentosans by Koji enzymes. 12 refs.« less

Rheology of corn stover slurries during fermentation to ethanol

NASA Astrophysics Data System (ADS)

Ghosh, Sanchari; Epps, Brenden; Lynd, Lee

2017-11-01

In typical processes that convert cellulosic biomass into ethanol fuel, solubilization of the biomass is carried out by saccharolytic enzymes; however, these enzymes require an expensive pretreatment step to make the biomass accessible for solubilization (and subsequent fermentation). We have proposed a potentially-less-expensive approach using the bacterium Clostridium thermocellum, which can initiate fermentation without pretreatment. Moreover, we have proposed a ``cotreatment'' process, in which fermentation and mechanical milling occur alternately so as to achieve the highest ethanol yield for the least milling energy input. In order to inform the energetic requirements of cotreatment, we experimentally characterized the rheological properties of corn stover slurries at various stages of fermentation. Results show that a corn stover slurry is a yield stress fluid, with shear thinning behavior well described by a power law model. Viscosity decreases dramatically upon fermentation, controlling for variables such as solids concentration and particle size distribution. To the authors' knowledge, this is the first study to characterize the changes in the physical properties of biomass during fermentation by a thermophilic bacterium.

Simultaneous determination of free amino acids in Pu-erh tea and their changes during fermentation.

PubMed

Zhu, Yuchen; Luo, Yinghua; Wang, Pengpu; Zhao, Mengyao; Li, Lei; Hu, Xiaosong; Chen, Fang

2016-03-01

Pu-erh ripened tea is produced through a unique microbial fermentation process from the sun-dried leaves of large-leaf tea species (Camellia sinensis (Linn.) var. assamica (Masters) Kitamura) in Yunnan province of China. In this study, the changes of amino acid profiles during fermentation of Pu-erh tea were investigated, based on the improved HPLC-UV method with PITC pre-column derivatization for the simultaneous determination of twenty free amino acids. Results showed that aspartic acid, glutamic acid, arginine, alanine, theanine and tyrosine were the major amino acids in tea samples. Fermentation significantly influenced on the amino acid profiles. The total free amino acid contents significantly decreased during fermentation (p<0.05). Meanwhile, low amount of acrylamide were detected. Its concentration increased after 7-days' fermentation and then decreased gradually. The results provided the useful information for the manipulation of fermentation process according to the changes of amino acids and acrylamide contents in Pu-erh ripened tea. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Biotechnology of Ugba, a Nigerian Traditional Fermented Food Condiment

PubMed Central

Olasupo, Nurudeen A.; Okorie, Chimezie P.; Oguntoyinbo, Folarin A.

2016-01-01

Legumes and oil bean seeds used for the production of condiments in Africa are inedible in their natural state; they contain some anti-nutritional factors especially undigestible oligosaccharides and phytate. Fermentation impact desirable changes by reducing anti-nutritional factors and increasing digestibility. Ugba is an alkaline fermented African oil bean cotyledon (Pentaclethra macrophylla) produced by the Ibos and other ethnic groups in southern Nigeria. Seen as a family business in many homes, its preparation is in accordance with handed-down tradition from previous generations and serves as a cheap source of plant protein. Its consumption as a native salad is made possible by fermentation of the cotyledon for 2–5 days, but could also serve as a soup flavoring agent when fermentation last for 6–10 days. The fermentation process involved is usually natural with an attendant issue of product safety, quality and inconsistency. The production of this condiment is on a small scale and the equipment used are very rudimentary, devoid of good manufacturing procedures that call to question the issue of microbial safety. This paper therefore reviews the production process and the spectrum of microbial composition involved during fermentation. In addition, potential spoilage agents, nutritional and biochemical changes during production are examined. Furthermore, information that can support development of starter cultures for controlled fermentation process in order to guarantee microbiological safety, quality and improved shelf life are also discussed. PMID:27540371

Regulation mechanisms in mixed and pure culture microbial fermentation.

PubMed

Hoelzle, Robert D; Virdis, Bernardino; Batstone, Damien J

2014-11-01

Mixed-culture fermentation is a key central process to enable next generation biofuels and biocommodity production due to economic and process advantages over application of pure cultures. However, a key limitation to the application of mixed-culture fermentation is predicting culture product response, related to metabolic regulation mechanisms. This is also a limitation in pure culture bacterial fermentation. This review evaluates recent literature in both pure and mixed culture studies with a focus on understanding how regulation and signaling mechanisms interact with metabolic routes and activity. In particular, we focus on how microorganisms balance electron sinking while maximizing catabolic energy generation. Analysis of these mechanisms and their effect on metabolism dynamics is absent in current models of mixed-culture fermentation. This limits process prediction and control, which in turn limits industrial application of mixed-culture fermentation. A key mechanism appears to be the role of internal electron mediating cofactors, and related regulatory signaling. This may determine direction of electrons towards either hydrogen or reduced organics as end-products and may form the basis for future mechanistic models. © 2014 Wiley Periodicals, Inc.

Improving the detection of cocoa bean fermentation-related changes using image fusion

NASA Astrophysics Data System (ADS)

Ochoa, Daniel; Criollo, Ronald; Liao, Wenzhi; Cevallos-Cevallos, Juan; Castro, Rodrigo; Bayona, Oswaldo

2017-05-01

Complex chemical processes occur in during cocoa bean fermentation. To select well-fermented beans, experts take a sample of beans, cut them in half and visually check its color. Often farmers mix high and low quality beans therefore, chocolate properties are difficult to control. In this paper, we explore how close-range hyper- spectral (HS) data can be used to characterize the fermentation process of two types of cocoa beans (CCN51 and National). Our aim is to find spectral differences to allow bean classification. The main issue is to extract reliable spectral data as openings resulting from the loss of water during fermentation, can cover up to 40% of the bean surface. We exploit HS pan-sharpening techniques to increase the spatial resolution of HS images and filter out uneven surface regions. In particular, the guided filter PCA approach which has proved suitable to use high-resolution RGB data as guide image. Our preliminary results show that this pre-processing step improves the separability of classes corresponding to each fermentation stage compared to using the average spectrum of the bean surface.

Eco-friendly process combining physical-chemical and biological technics for the fermented dairy products waste pretreatment and reuse.

PubMed

Kasmi, Mariam; Hamdi, Moktar; Trabelsi, Ismail

2017-01-01

Residual fermented dairy products resulting from process defects or from expired shelf life products are considered as waste. Thus, dairies wastewater treatment plants (WWTP) suffer high input effluents polluting load. In this study, fermented residuals separation from the plant wastewater is proposed. In the aim to meet the municipal WWTP input limits, a pretreatment combining physical-chemical and biological processes was investigated to reduce residual fermented dairy products polluting effect. Yoghurt (Y) and fermented milk products (RL) were considered. Raw samples chemical oxygen demand (COD) values were assessed at 152 and 246 g.L -1 for Y and RL products, respectively. Following the thermal coagulation, maximum removal rates were recorded at 80 °C. Resulting whey stabilization contributed to the removal rates enhance to reach 72% and 87% for Y and RL samples; respectively. Residual whey sugar content was fermented using Candida strains. Bacterial growth and strains degrading potential were discussed. C. krusei strain achieved the most important removal rates of 78% and 85% with Y and RL medium, respectively. Global COD removal rates exceeded 93%.

Ethanol production from residual wood chips of cellulose industry: acid pretreatment investigation, hemicellulosic hydrolysate fermentation, and remaining solid fraction fermentation by SSF process.

PubMed

Silva, Neumara Luci Conceição; Betancur, Gabriel Jaime Vargas; Vasquez, Mariana Peñuela; Gomes, Edelvio de Barros; Pereira, Nei

2011-04-01

Current research indicates the ethanol fuel production from lignocellulosic materials, such as residual wood chips from the cellulose industry, as new emerging technology. This work aimed at evaluating the ethanol production from hemicellulose of eucalyptus chips by diluted acid pretreatment and the subsequent fermentation of the generated hydrolysate by a flocculating strain of Pichia stipitis. The remaining solid fraction generated after pretreatment was subjected to enzymatic hydrolysis, which was carried out simultaneously with glucose fermentation [saccharification and fermentation (SSF) process] using a strain of Saccharomyces cerevisiae. The acid pretreatment was evaluated using a central composite design for sulfuric acid concentration (1.0-4.0 v/v) and solid to liquid ratio (1:2-1:4, grams to milliliter) as independent variables. A maximum xylose concentration of 50 g/L was obtained in the hemicellulosic hydrolysate. The fermentation of hemicellulosic hydrolysate and the SSF process were performed in bioreactors and the final ethanol concentrations of 15.3 g/L and 28.7 g/L were obtained, respectively.

Developing a sustainable bioprocessing strategy based on a generic feedstock.

PubMed

Webb, C; Koutinas, Wang R; Wang, R

2004-01-01

Based on current average yields of wheat per hectare and the saccharide content of wheat grain, it is feasible to produce wheat-based alternatives to many petrochemicals. However, the requirements in terms of wheat utilization would be equivalent to 82% of current production if intermediates and primary building blocks such as ethylene, propylene, and butadiene were to be produced in addition to conventional bioproducts. If only intermediates and bioproducts were produced this requirement would fall to just 11%, while bioproducts alone would require only 7%. These requirements would be easily met if the global wheat yield per hectare of cultivated land was increased from the current average of 2.7 to 5.5 tonnes ha(-1) (well below the current maximum). Preliminary economic evaluation taking into account only raw material costs demonstrated that the use of wheat as a generic feedstock could be advantageous in the case of bioproducts and specific intermediate petrochemicals. Gluten plays a significant role considering the revenue occurring when it is sold as a by-product. A process leading to the production of a generic fermentation feedstock from wheat has been devised and evaluated in terms of efficiency and economics. This feedstock aims at providing a replacement for conventional fermentation media and petrochemical feedstocks. The process can be divided into four major stages--wheat milling; fermentation of whole wheat flour by A. awamori leading to the production of enzymes and fungal cells; glucose enhancement via enzymatic hydrolysis of flour suspensions; and nitrogen/micronutrient enhancement via fungal cell autolysis. Preliminary costings show that the operating cost of the process depends on plant capacity, cereal market price, presence and market value of added-value by-products, labour costs, and mode of processing (batch or continuous).

Extraction of glutathione from EFB fermentation waste using methanol with sonication process

NASA Astrophysics Data System (ADS)

Muryanto, Muryanto; Alvin, Nurdin, Muhammad; Hanifah, Ummu; Sudiyani, Yanni

2017-11-01

Glutathione is important compound on the human body. Glutathione have a widely use at pharmacy and cosmetics as detoxification, skin whitening agent, antioxidant and many other. This study aims to obtain glutathione from Saccharomyces cerevisiae in fermentation waste of second generation bioethanol. The remaining yeast in the empty fruit bunch (EFB) fermentation was separated from the fermentation solution use centrifugation process and then extracted using a methanol-water solution. The extraction process was done by maceration which was assisted by sonication process. Solvent concentration and time of sonication were varied to see its effect on glutathione concentration. The concentration of glutathione from the extraction process was analyzed using alloxan method with UV-Vis spectrophotometer. The results show that the highest glutathione concentration was approximately 1.32 g/L obtained with methanol solvent at 90 minutes of maceration following with 15 minutes sonication.

Scale Up of Malonic Acid Fermentation Process: Cooperative Research and Development Final Report, CRADA Number CRD-16-612

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

Schell, Daniel J

The goal of this work is to use the large fermentation vessels in the National Renewable Energy Laboratory's (NREL) Integrated Biorefinery Research Facility (IBRF) to scale-up Lygos' biological-based process for producing malonic acid and to generate performance data. Initially, work at the 1 L scale validated successful transfer of Lygos' fermentation protocols to NREL using a glucose substrate. Outside of the scope of the CRADA with NREL, Lygos tested their process on lignocellulosic sugars produced by NREL at Lawrence Berkeley National Laboratory's (LBNL) Advanced Biofuels Process Development Unit (ABPDU). NREL produced these cellulosic sugar solutions from corn stover using amore » separate cellulose/hemicellulose process configuration. Finally, NREL performed fermentations using glucose in large fermentors (1,500- and 9,000-L vessels) to intermediate product and to demonstrate successful performance of Lygos' technology at larger scales.« less

Review of enhanced processes for anaerobic digestion treatment of sewage sludge

NASA Astrophysics Data System (ADS)

Liu, Xinyuan; Han, Zeyu; Yang, Jie; Ye, Tianyi; Yang, Fang; Wu, Nan; Bao, Zhenbo

2018-02-01

Great amount of sewage sludge had been produced each year, which led to serious environmental pollution. Many new technologies had been developed recently, but they were hard to be applied in large scales. As one of the traditional technologies, anaerobic fermentation process was capable of obtaining bioenergy by biogas production under the functions of microbes. However, the anaerobic process is facing new challenges due to the low fermentation efficiency caused by the characteristics of sewage sludge itself. In order to improve the energy yield, the enhancement technologies including sewage sludge pretreatment process, co-digestion process, high-solid digestion process and two-stage fermentation process were widely studied in the literatures, which were introduced in this article.

Production and purification of anti-bacterial biometabolite from wild-type Lactobacillus, isolated from fermented bamboo shoot: future suggestions and a proposed system for secondary metabolite onsite recovery during continuous fermentation.

PubMed

Badwaik, Laxmikant S; Borah, Pallab Kumar; Deka, Sankar C

2015-02-01

Wild-type lactobacillus isolated form Khorisa, a fermented bamboo shoot product of Assam, India were evaluated for production anti-bacterial secondary biometabolites, against Staphylococcus aureus. Submerged fermentation technique was used for the production of secondary anti-microbial biometabolite by a single wild-type lactobacillus strain, which tested positive for the release of anti-bacterial factor(s). Crude cell-free supernatant was obtained, followed by extraction in water-immiscible solvents viz., chloroform, hexane, petroleum ether. Chloroform extract of cell-free crude supernatant showed maximum yield (0.054 g/ml) and inhibited all indicator bacterial strains viz., Escherichia coli, Staphylococcus aureus, and Bacillus cereus. Yields of hexane and petroleum ether extract were 0.052 and 0.026 g/ml, respectively. Minimum lethal dose concentration assay of the chloroform extract showed LDmin values at 27, 1.68, and 1.68 mg/ml for E. coli, S. aureus, and B. cereus, respectively. Kill time for all the indicator bacterial strains were less than 12 h. The efficacy of the anti-bacterial substance seemed to depend on the presence of organic acids, particularly lactic acid. Conceptual-based suggestion for the development of an onsite secondary metabolites recovery system during continuous fermentation has also been attempted.

Study on feasibility of determination of glucosamine content of fermentation process using a micro NIR spectrometer.

PubMed

Sun, Zhongyu; Li, Can; Li, Lian; Nie, Lei; Dong, Qin; Li, Danyang; Gao, Lingling; Zang, Hengchang

2018-08-05

N-acetyl-d-glucosamine (GlcNAc) is a microbial fermentation product, and NIR spectroscopy is an effective process analytical technology (PAT) tool in detecting the key quality attribute: the GlcNAc content. Meanwhile, the design of NIR spectrometers is under the trend of miniaturization, portability and low-cost nowadays. The aim of this study was to explore a portable micro NIR spectrometer with the fermentation process. First, FT-NIR spectrometer and Micro-NIR 1700 spectrometer were compared with simulated fermentation process solutions. The R c 2 , R p 2 , RMSECV and RMSEP of the optimal FT-NIR and Micro-NIR 1700 models were 0.999, 0.999, 3.226 g/L, 1.388 g/L and 0.999, 0.999, 1.821 g/L, 0.967 g/L. Passing-Bablok regression method and paired t-test results showed there were no significant differences between the two instruments. Then the Micro-NIR 1700 was selected for the practical fermentation process, 135 samples from 10 batches were collected. Spectral pretreatment methods and variables selection methods (BiPLS, FiPLS, MWPLS and CARS-PLS) for PLS modeling were discussed. The R c 2 , R p 2 , RMSECV and RMSEP of the optimal GlcNAc content PLS model of the practical fermentation process were 0.994, 0.995, 2.792 g/L and 1.946 g/L. The results have a positive reference for application of the Micro-NIR spectrometer. To some extent, it could provide theoretical supports in guiding the microbial fermentation or the further assessment of bioprocess. Copyright © 2018. Published by Elsevier B.V.

System for extracting protein from a fermentation product

DOEpatents

Lawton, Jr., John Warren; Bootsma, Jason Alan; Lewis, Stephen Michael

2016-04-26

A method of producing bioproducts from a feedstock in a system configured to produce ethanol and distillers grains from a fermentation product is disclosed. A system configured to process feedstock into a fermentation product and bioproducts including ethanol and meal is disclosed. A bioproduct produced from a fermentation product produced from a feedstock in a biorefining system is disclosed.

Method for extracting protein from a fermentation product

DOEpatents

Lawton, Jr., John Warren; Bootsma, Jason Alan; Lewis, Stephen Michael

2014-02-18

A method of producing bioproducts from a feedstock in a system configured to produce ethanol and distillers grains from a fermentation product is disclosed. A system configured to process feedstock into a fermentation product and bioproducts including ethanol and meal is disclosed. A bioproduct produced from a fermentation product produced from a feedstock in a biorefining system is disclosed.

Production of fermentable sugars from corn fiber using soaking in aqueous ammonia (saa) pretreatment and fermentation to succinic acid by Escherichia coli afp184

USDA-ARS?s Scientific Manuscript database

Conversion of corn fiber (CF), a by-product from the corn-to-ethanol conversion process, into fermentable sugar and succinic acid was investigated using soaking in aqueous ammonia (SAA) pretreatment followed by biological conversions including enzymatic hydrolysis and fermentation using genetically ...

21 CFR 173.150 - Milk-clotting enzymes, microbial.

Code of Federal Regulations, 2010 CFR

2010-04-01

.... Milk-clotting enzyme produced by pure-culture fermentation process may be safely used in the production... from one of the following organisms by a pure-culture fermentation process: (1) Endothia parasitica...

Genomics of Aspergillus oryzae: Learning from the History of Koji Mold and Exploration of Its Future

PubMed Central

Machida, Masayuki; Yamada, Osamu; Gomi, Katsuya

2008-01-01

At a time when the notion of microorganisms did not exist, our ancestors empirically established methods for the production of various fermentation foods: miso (bean curd seasoning) and shoyu (soy sauce), both of which have been widely used and are essential for Japanese cooking, and sake, a magical alcoholic drink consumed at a variety of ritual occasions, are typical examples. A filamentous fungus, Aspergillus oryzae, is the key organism in the production of all these traditional foods, and its solid-state cultivation (SSC) has been confirmed to be the secret for the high productivity of secretory hydrolases vital for the fermentation process. Indeed, our genome comparison and transcriptome analysis uncovered mechanisms for effective degradation of raw materials in SSC: the extracellular hydrolase genes that have been found only in the A. oryzae genome but not in A. fumigatus are highly induced during SSC but not in liquid cultivation. Also, the temperature reduction process empirically adopted in the traditional soy-sauce fermentation processes has been found to be important to keep strong expression of the A. oryzae-specific extracellular hydrolases. One of the prominent potentials of A. oryzae is that it has been successfully applied to effective degradation of biodegradable plastic. Both cutinase, responsible for the degradation of plastic, and hydrophobin, which recruits cutinase on the hydrophobic surface to enhance degradation, have been discovered in A. oryzae. Genomic analysis in concert with traditional knowledge and technology will continue to be powerful tools in the future exploration of A. oryzae. PMID:18820080

Microbial succession and the functional potential during the fermentation of Chinese soy sauce brine

PubMed Central

Sulaiman, Joanita; Gan, Han Ming; Yin, Wai-Fong; Chan, Kok-Gan

2014-01-01

The quality of traditional Chinese soy sauce is determined by microbial communities and their inter-related metabolic roles in the fermentation tank. In this study, traditional Chinese soy sauce brine samples were obtained periodically to monitor the transitions of the microbial population and functional properties during the 6 months of fermentation process. Whole genome shotgun method revealed that the fermentation brine was dominated by the bacterial genus Weissella and later dominated by the fungal genus Candida. Metabolic reconstruction of the metagenome sequences demonstrated a characteristic profile of heterotrophic fermentation of proteins and carbohydrates. This was supported by the detection of ethanol with stable decrease of pH values. To the best of our knowledge, this is the first study that explores the temporal changes in microbial successions over a period of 6 months, through metagenome shotgun sequencing in traditional Chinese soy sauce fermentation and the biological processes therein. PMID:25400624

Microbial succession and the functional potential during the fermentation of Chinese soy sauce brine.

PubMed

Sulaiman, Joanita; Gan, Han Ming; Yin, Wai-Fong; Chan, Kok-Gan

2014-01-01

The quality of traditional Chinese soy sauce is determined by microbial communities and their inter-related metabolic roles in the fermentation tank. In this study, traditional Chinese soy sauce brine samples were obtained periodically to monitor the transitions of the microbial population and functional properties during the 6 months of fermentation process. Whole genome shotgun method revealed that the fermentation brine was dominated by the bacterial genus Weissella and later dominated by the fungal genus Candida. Metabolic reconstruction of the metagenome sequences demonstrated a characteristic profile of heterotrophic fermentation of proteins and carbohydrates. This was supported by the detection of ethanol with stable decrease of pH values. To the best of our knowledge, this is the first study that explores the temporal changes in microbial successions over a period of 6 months, through metagenome shotgun sequencing in traditional Chinese soy sauce fermentation and the biological processes therein.

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

PubMed

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

2007-12-01

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

Selection of starter cultures for the production of sour cassava starch in a pilot-scale fermentation process.

PubMed

Penido, Fernanda Corrêa Leal; Piló, Fernanda Barbosa; Sandes, Sávio Henrique de Cicco; Nunes, Álvaro Cantini; Colen, Gecernir; Oliveira, Evelyn de Souza; Rosa, Carlos Augusto; Lacerda, Inayara Cristina Alves

2018-02-28

Sour cassava starch (Polvilho azedo) is obtained from a spontaneous fermentation conducted by microorganisms from raw materials and fermentation tanks. This product is traditionally used in the baking industry for the manufacture of biscuits and Brazilian cheese breads. However, the end of fermentation is evaluated empirically, and the process occurs without standardization, which results in products of inconsistent quality. Predominant microbiota from a cassava flour manufacturer was isolated in order to select starter cultures for the production of sour cassava starch in a pilot-scale fermentation process. Lactic acid bacteria and yeasts were isolated, enumerated and grouped by Restriction Fragment Length Polymorphism, and PCR fingerprinting, respectively. One isolate of each molecular profile was identified by sequencing of the rRNA gene. LAB were prevalent throughout the entire process. Lactobacillus brevis (21.5%), which produced the highest values of acidity, and Lactobacillus plantarum (13.9%) were among the most frequent species. Pichia scutulata (52.2%) was the prevalent yeast and showed amylolytic activity. The aforementioned species were tested as single and mixed starter cultures in a pilot-scale fermentation process for 28 days. L. plantarum exhibited better performance as a starter culture, which suggests its potential for the production of sour cassava starch. Copyright © 2018 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

40 CFR 63.2171 - How do I demonstrate continuous compliance with the emission limitations?

Code of Federal Regulations, 2010 CFR

2010-07-01

... Nutritional Yeast Continuous Compliance Requirements § 63.2171 How do I demonstrate continuous compliance with... each fermentation stage for which emission limits apply. To calculate the 12-month percentage, do not...

Modification of ruminal fermentation and methane production by adding legumes containing condensed tannins to an orchardgrass diet in continuous culture systems

USDA-ARS?s Scientific Manuscript database

Condensed tannins (CT) can alter ruminal fermentation and enteric methane (CH4) production in ruminants; however, research is lacking on how increased CT levels affect nutrient digestibility, volatile fatty acid (VFA) production, bacterial protein synthesis, fatty acid (FA) profiles, protozoal popul...

40 CFR 63.2192 - What definitions apply to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Manufacturing of Nutritional Yeast... addition of yeast to the fermenter; the period ends at the earlier of either the end of aeration or the point at which the yeast has begun being emptied from the fermenter. Brew means the mixture of yeast and...

40 CFR 63.2192 - What definitions apply to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Manufacturing of Nutritional Yeast... addition of yeast to the fermenter; the period ends at the earlier of either the end of aeration or the point at which the yeast has begun being emptied from the fermenter. Brew means the mixture of yeast and...

40 CFR 63.2192 - What definitions apply to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Manufacturing of Nutritional Yeast... addition of yeast to the fermenter; the period ends at the earlier of either the end of aeration or the point at which the yeast has begun being emptied from the fermenter. Brew means the mixture of yeast and...

76 FR 55572 - Approval and Promulgation of Implementation Plans; Georgia: Prevention of Significant...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-08

...) Exclude facilities that produce ethanol through a natural fermentation process from the definition of... 24060) which exclude facilities that produce ethanol through a natural fermentation process from the...

Production of ethanol and feed by high dry matter hydrolysis and fermentation of palm kernel press cake.

PubMed

Jørgensen, Henning; Sanadi, Anand R; Felby, Claus; Lange, Niels Erik Krebs; Fischer, Morten; Ernst, Steffen

2010-05-01

Palm kernel press cake (PKC) is a residue from palm oil extraction presently only used as a low protein feed supplement. PKC contains 50% fermentable hexose sugars present in the form of glucan and mainly galactomannan. This makes PKC an interesting feedstock for processing into bioethanol or in other biorefinery processes. Using a combination of mannanase, beta-mannosidase, and cellulases, it was possible without any pretreatment to hydrolyze PKC at solid concentrations of 35% dry matter with mannose yields up to 88% of theoretical. Fermentation was tested using Saccharomyces cerevisiae in both a separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) setup. The hydrolysates could readily be fermented without addition of nutrients and with average fermentation yields of 0.43 +/- 0.02 g/g based on consumed mannose and glucose. Employing SSF, final ethanol concentrations of 70 g/kg was achieved in 216 h, corresponding to an ethanol yield of 70% of theoretical or 200 g ethanol/kg PKC. Testing various enzyme mixtures revealed that including cellulases in combination with mannanases significantly improved ethanol yields. Processing PKC to ethanol resulted in a solid residue enriched in protein from 17% to 28%, a 70% increase, thereby potentially making a high-protein containing feed supplement.

Kinetic analysis of beer primary fermentation using yeast cells immobilized by ceramic support adsorption and alginate gel entrapment.

PubMed

Zhang, Yongming; Kennedy, John F; Knill, Charles J; Panesar, Parmjit S

2006-01-01

Yeast cells were immobilized by absorption onto porous ceramic support and evaluated for continuous beer primary fermentation using a bioreactor in comparison to yeast cells immobilized by entrapment in calcium alginate gel. The effects of temperature and flow rate as a function of reaction/fermentation time on fermentation rate were investigated. The fermentation reaction (in terms of loss of total soluble solids in the beer wort as a function of time) was first-order with half-lifes in the range of approximately 9-11 hours at approximately 10-12 degrees C at beer wort linear flow rates of approximately 0.8-1.6 cm/minute for ceramic support, compared with approximately 16 hours for Ca-alginate gel, the former support matrix being more efficient and demonstrating greater potential for future commercial application.

The effect of oyster mushroom (Pleurotus ostreatus) powder as prebiotic agent on yoghurt quality

NASA Astrophysics Data System (ADS)

Tupamahu, Ivana Putri Christantia; Budiarso, Tri Yahya

2017-05-01

Mushroom has already been known as a good source of proteins, carbohydrates and some vitamins. It is then the objective of this research to find out the effect of oyster mushroom (Pleurotus ostreatus) powder addition on yoghurt fermentation. The resulting yoghurt product will be monitor by measuring its total lactic acids, acidity (pH), lactic acid bacteria (LAB) count, and the organoleptic properties, including colour, taste, flavour and texture. The mushroom were dried and grinded into powder up to 200 mashes, continued with its addition in yoghurt making process. Mushroom powder concentrations of 0%, 0.5%, 1%, and 1.5% were added on the milk to be fermented. The result showed that mushroom powder addition resulting in increase lactic acid concentration, reduced its acidity, and increased LAB viability. Based on the lactic acid counts, acidity, and LAB viability, a concentration of 1.5% powder addition is the optimal concentration for fermentation, but the product is not preferred by the panelists. The addition of 1% mushroom powder resulting in increased yoghurt quality, and the preferred yoghurt product by most of the panelists. It is then proven that the addition of mushroom powder will increase yoghurt quality and public acceptance.

Use of real time gas production data for more accurate comparison of continuous single-stage and two-stage fermentation.

PubMed

Massanet-Nicolau, Jaime; Dinsdale, Richard; Guwy, Alan; Shipley, Gary

2013-02-01

Changes in fermenter gas composition within a given 24h period can cause severe bias in calculations of biogas or energy yields based on just one or two measurements of gas composition per day, as is common in other studies of two-stage fermentation. To overcome this bias, real time recording of gas composition and production were used to undertake a detailed and controlled comparison of single-stage and two-stage fermentation using a real world substrate (wheat feed pellets). When a two-stage fermentation system was used, methane yields increased from 261 L kg(-1)VS using a 20 day HRT, single-stage fermentation, to 359 L kg(-1) VS using a two-stage fermentation with the same overall retention time--an increase of 37%. Additionally a hydrogen yield of 7 L kg(-1) VS was obtained when two-stage fermentation was used. The two-stage system could also be operated at a shorter, 12 day HRT and still produce higher methane yields (306 L kg(-1) VS). Both two-stage fermentation systems evaluated exhibited methane yields in excess of that predicted by a biological methane potential test (BMP) performed using the same feedstock (260 L kg(-1)VS). Copyright © 2012 Elsevier Ltd. All rights reserved.

Continuous high-solids corn liquefaction and fermentation with stripping of ethanol.

PubMed

Taylor, Frank; Marquez, Marco A; Johnston, David B; Goldberg, Neil M; Hicks, Kevin B

2010-06-01

Removal of ethanol from the fermentor during fermentation can increase productivity and reduce the costs for dewatering the product and coproduct. One approach is to recycle the fermentor contents through a stripping column, where a non-condensable gas removes ethanol to a condenser. Previous research showed that this approach is feasible. Savings of $0.03 per gallon were predicted at 34% corn dry solids. Greater savings were predicted at higher concentration. Now the feasibility has been demonstrated at over 40% corn dry solids, using a continuous corn liquefaction system. A pilot plant, that continuously fed corn meal at more than one bushel (25 kg) per day, was operated for 60 consecutive days, continuously converting 95% of starch and producing 88% of the maximum theoretical yield of ethanol. A computer simulation was used to analyze the results. The fermentation and stripping systems were not significantly affected when the CO(2) stripping gas was partially replaced by nitrogen or air, potentially lowering costs associated with the gas recycle loop. It was concluded that previous estimates of potential cost savings are still valid. (c) 2010. Published by Elsevier Ltd. All rights reserved.

Fermentation pre-treatment of landfill leachate for enhanced electron recovery in a microbial electrolysis cell.

PubMed

Mahmoud, Mohamed; Parameswaran, Prathap; Torres, César I; Rittmann, Bruce E

2014-01-01

Pre-fermentation of poorly biodegradable landfill leachate (BOD5/COD ratio of 0.32) was evaluated for enhanced current density (j), Coulombic efficiency (CE), Coulombic recovery (CR), and removal of organics (BOD5 and COD) in a microbial electrolysis cell (MEC). During fermentation, the complex organic matter in the leachate was transformed to simple volatile fatty acids, particularly succinate and acetate in batch tests, but mostly acetate in semi-continuous fermentation. Carbohydrate had the highest degree of fermentation, followed by protein and lipids. j, CE, CR, and BOD5 removal were much greater for an MEC fed with fermented leachate (23 A/m(3) or 16 mA/m(2), 68%, 17.3%, and 83%, respectively) compared to raw leachate (2.5 A/m(3) or 1.7 mA/m(2), 56%, 2.1%, and 5.6%, respectively). All differences support the value of pre-fermentation before an MEC for stabilization of BOD5 and enhanced electron recovery as current when treating a recalcitrant wastewater like landfill leachate. Copyright © 2013 Elsevier Ltd. All rights reserved.

Produce from Africa’s Gardens: Potential for Leafy Vegetable and Fruit Fermentations

PubMed Central

Oguntoyinbo, Folarin A.; Fusco, Vincenzina; Cho, Gyu-Sung; Kabisch, Jan; Neve, Horst; Bockelmann, Wilhelm; Huch, Melanie; Frommherz, Lara; Trierweiler, Bernhard; Becker, Biserka; Benomar, Nabil; Gálvez, Antonio; Abriouel, Hikmate; Holzapfel, Wilhelm H.; Franz, Charles M. A. P.

2016-01-01

A rich variety of indigenous fruits and vegetables grow in Africa, which contribute to the nutrition and health of Africa’s populations. Fruits and vegetables have high moisture and are thus inherently prone to accelerated spoilage. Food fermentation still plays a major role in combating food spoilage and foodborne diseases that are prevalent in many of Africa’s resource disadvantaged regions. Lactic acid fermentation is probably the oldest and best-accepted food processing method among the African people, and is largely a home-based process. Fermentation of leafy vegetables and fruits is, however, underutilized in Africa, although such fermented products could contribute toward improving nutrition and food security in this continent, where many are still malnourished and suffer from hidden hunger. Fermentation of leafy vegetables and fruits may not only improve safety and prolong shelf life, but may also enhance the availability of some trace minerals, vitamins and anti-oxidants. Cassava, cow-peas, amaranth, African nightshade, and spider plant leaves have a potential for fermentation, as do various fruits for the production of vinegars or fruit beers and wines. What is needed to accelerate efforts for production of fermented leaves and vegetables is the development of fermentation protocols, training of personnel and scale-up of production methods. Furthermore, suitable starter cultures need to be developed and produced to guarantee the success of the fermentations. PMID:27458430

Bacterial Diversity Analysis during the Fermentation Processing of Traditional Chinese Yellow Rice Wine Revealed by 16S rDNA 454 Pyrosequencing.

PubMed

Fang, Ruo-si; Dong, Ya-chen; Chen, Feng; Chen, Qi-he

2015-10-01

Rice wine is a traditional Chinese fermented alcohol drink. Spontaneous fermentation with the use of the Chinese starter and wheat Qu lead to the growth of various microorganisms during the complete brewing process. It's of great importance to fully understand the composition of bacteria diversity in rice wine in order to improve the quality and solve safety problems. In this study, a more comprehensive bacterial description was shown with the use of bacteria diversity analysis, which enabled us to have a better understanding. Rarefaction, rank abundance, alpha Diversity, beta diversity and principal coordinates analysis simplified their complex bacteria components and provide us theoretical foundation for further investigation. It has been found bacteria diversity is more abundant at mid-term and later stage of brewing process. Bacteria community analysis reveals there is a potential safety hazard existing in the fermentation, since most of the sequence reads are assigned to Enterobacter (7900 at most) and Pantoea (7336 at most), followed by Staphylococcus (2796 at most) and Pseudomonas (1681 at most). Lactic acid bacteria are rare throughout the fermentation process which is not in accordance with other reports. This work may offer us an opportunity to investigate micro ecological fermentation system in food industry. © 2015 Institute of Food Technologists®

High-Throughput rRNA Gene Sequencing Reveals High
and Complex Bacterial Diversity Associated with
Brazilian Coffee Bean Fermentation

PubMed Central

Vinícius de Melo, Gilberto

2018-01-01

Summary Coffee bean fermentation is a spontaneous, on-farm process involving the action of different microbial groups, including bacteria and fungi. In this study, high-throughput sequencing approach was employed to study the diversity and dynamics of bacteria associated with Brazilian coffee bean fermentation. The total DNA from fermenting coffee samples was extracted at different time points, and the 16S rRNA gene with segments around the V4 variable region was sequenced by Illumina high-throughput platform. Using this approach, the presence of over eighty bacterial genera was determined, many of which have been detected for the first time during coffee bean fermentation, including Fructobacillus, Pseudonocardia, Pedobacter, Sphingomonas and Hymenobacter. The presence of Fructobacillus suggests an influence of these bacteria on fructose metabolism during coffee fermentation. Temporal analysis showed a strong dominance of lactic acid bacteria with over 97% of read sequences at the end of fermentation, mainly represented by the Leuconostoc and Lactococcus. Metabolism of lactic acid bacteria was associated with the high formation of lactic acid during fermentation, as determined by HPLC analysis. The results reported in this study confirm the underestimation of bacterial diversity associated with coffee fermentation. New microbial groups reported in this study may be explored as functional starter cultures for on-farm coffee processing.

Comparative studies on the alcohol types presence in Gracilaria sp. and rice fermentation using Sasad

NASA Astrophysics Data System (ADS)

Mansa, R.; Mansuit, H.; Sipaut, C. S.; Yee, C. F.; Yasir, S. M.

2016-06-01

Alternative fuel sources such as biofuels are needed in order to overcome environmental problem caused by fossil fuel consumption. Currently, most biofuel are produced from land based crops and there is a possibility that marine biomass such as macroalgae can be an alternative source for biofuel production. The carbohydrate in macroalgae can be broken down into simple sugar through thermo-chemical hydrolysis and enzymatic hydrolysis. Dilute-acid hydrolysis was believed to be the most available and affordable method. However, the process may release inhibitors which would affect alcohol yield from fermentation. Thus, this work was aimed at investigating if it is possible to avoid this critical pre-treatment step in macroalgae fermentation process by using Sasad, a local Sabahan fermentation agent and to compare the yield with rice wine fermentation. This work hoped to determine and compare the alcohol content from Gracilaria sp. and rice fermentation with Sasad. Rice fermentation was found containing ethanol and 2 - methyl - 1 - propanol. Fermentation of Gracilaria sp. had shown the positive presence of 3 - methyl - 1 - butanol. It was found that Sasad can be used as a fermentation agent for bioalcohol production from Gracilaria sp. without the need for a pretreatment step. However further investigations are needed to determine if pre-treatment would increase the yield of alcohol.

New process for production of fermented black table olives using selected autochthonous microbial resources

PubMed Central

Tufariello, Maria; Durante, Miriana; Ramires, Francesca A.; Grieco, Francesco; Tommasi, Luca; Perbellini, Ezio; Falco, Vittorio; Tasioula-Margari, Maria; Logrieco, Antonio F.; Mita, Giovanni; Bleve, Gianluca

2015-01-01

Table olives represent one important fermented product in Europe and, in the world, their demand is constantly increasing. At the present time, no systems are available to control black table olives spontaneous fermentation by the Greek method. During this study, a new protocol for the production of black table olives belonging to two Italian (Cellina di Nardò and Leccino) and two Greek (Kalamàta and Conservolea) cultivars has been developed: for each table olive cultivar, starter-driven fermentations were performed inoculating, firstly, one selected autochthonous yeast starter and, subsequently, one selected autochthonous LAB starter. All starters formulation were able to dominate fermentation process. The olive fermentation was monitored using specific chemical descriptors able to identify a first stage (30 days) mainly characterized by aldehydes; a second period (60 days) mainly characterized by higher alcohols, styrene and terpenes; a third fermentation stage represented by acetate esters, esters and acids. A significant decrease of fermentation time (from 8 to 12 months to a maximum of 3 months) and an significant improvement in organoleptic characteristics of the final product were obtained. This study, for the first time, describes the employment of selected autochthonous microbial resources optimized to mimic the microbial evolution already recorded during spontaneous fermentations. PMID:26441932

Enhanced power generation and energy conversion of sewage sludge by CEA-microbial fuel cells.

PubMed

Abourached, Carole; Lesnik, Keaton Larson; Liu, Hong

2014-08-01

The production of methane from sewage sludge through the use of anaerobic digestion has been able to effectively offset energy costs for wastewater treatment. However, significant energy reserves are left unrecovered and effluent standards are not met necessitating secondary processes such as aeration. In the current study a novel cloth-electrode assembly microbial fuel cell (CEA-MFC) was used to generate electricity from sewage sludge. Fermentation pretreatment of the sludge effectively increased the COD of the supernatant and improved reactor performance. Using the CEA-MFC design, a maximum power density of 1200 mW m(-2) was reached after a fermentation pre-treatment time of 96 h. This power density represents a 275% increase over those previously observed in MFC systems. Results indicate continued improvements are possible and MFCs may be a viable modification to existing wastewater treatment infrastructure. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Analysis of changes in minerals contents during cider fermentation process by inductively coupled plasma mass spectrometry].

PubMed

Ye, Meng-qi; Yue, Tian-li; Gao, Zhen-peng; Yuan, Ya-hong; Nie, Gang

2015-01-01

The changes in mineral elements during cider fermentation process were determined using ICP-MS. The results showed that the main minerals in the fermentation liquor included K, Na, Ca, Mg, Fe, Mn, Zn, Cu, Sr and B. The content of K was the highest in both the apple juice and the cider, being 1 853. 83 and 1 654. 38 mg . L-1 respectively. The content of minerals was in dynamic changes along with the fermentation process. As a whole, during 72-120 h and 144-216 h, most of the minerals contents underwent great fluctuation. Especially when fermented for 192 h, the content of most of the minerals reached peak value or valley value. The content of Fe and Zn achieved their peak value, while the content of K, Na, Ca, Mg, Mn and B achieved valley value. But during the following 24 h, the content of minerals underwent a sharp reversal. After fermentation, the content of K, Mg, Cu, Zn and B decreased significantly, while the content of Na, Ca, Mn, Fe and Sr did not change significantly. The correlational analysis was conducted to evaluate the correlation between the mineral elements, and the result showed that the correlation between Ca and Mn was the most significant, with the correlation index reaching 0. 924. The information of this study will supply sufficient data for the fermentation process control and quality improvement of cider.

Fed-batch hydrolysate addition and cell separation by settling in high cell density lignocellulosic ethanol fermentations on AFEX™ corn stover in the Rapid Bioconversion with Integrated recycling Technology process.

PubMed

Sarks, Cory; Jin, Mingjie; Balan, Venkatesh; Dale, Bruce E

2017-09-01

The Rapid Bioconversion with Integrated recycling Technology (RaBIT) process uses enzyme and yeast recycling to improve cellulosic ethanol production economics. The previous versions of the RaBIT process exhibited decreased xylose consumption using cell recycle for a variety of different micro-organisms. Process changes were tested in an attempt to eliminate the xylose consumption decrease. Three different RaBIT process changes were evaluated in this work including (1) shortening the fermentation time, (2) fed-batch hydrolysate addition, and (3) selective cell recycling using a settling method. Shorting the RaBIT fermentation process to 11 h and introducing fed-batch hydrolysate addition eliminated any xylose consumption decrease over ten fermentation cycles; otherwise, decreased xylose consumption was apparent by the third cell recycle event. However, partial removal of yeast cells during recycle was not economical when compared to recycling all yeast cells.

Yeast population dynamics of industrial fuel-ethanol fermentation process assessed by PCR-fingerprinting.

PubMed

da Silva-Filho, Eurípedes Alves; Brito dos Santos, Scheila Karina; Resende, Alecsandra do Monte; de Morais, José Otamar Falcão; de Morais, Marcos Antonio; Ardaillon Simões, Diogo

2005-07-01

Yeast population used in industrial production of fuel-ethanol may vary according to the plant process condition and to the environmental stresses imposed to yeast cells. Therefore, yeast strains isolated from a particular industrial process may be adapted to such conditions and should be used as starter strain instead of less adapted commercial strains. This work reports the use of PCR-fingerprinting method based on microsatellite primer (GTG)5 to characterize the yeast population dynamics along the fermentation period in six distilleries. The results show that indigenous fermenting strains present in the crude substrate can be more adapted to the industrial process than commercial strains. We also identified new strains that dominate the yeast population and were more present either in molasses or sugar cane fermenting distilleries. Those strains were proposed to be used as starters in those industrial processes. This is the first report on the use of molecular markers to discriminate Saccharomyces cerevisiae strains from fuel-ethanol producing process.

A novel process for recovery of fermentation-derived succinic acid: process design and economic analysis.

PubMed

Orjuela, Alvaro; Orjuela, Andrea; Lira, Carl T; Miller, Dennis J

2013-07-01

Recovery and purification of organic acids produced in fermentation constitutes a significant fraction of total production cost. In this paper, the design and economic analysis of a process to recover succinic acid (SA) via dissolution and acidification of succinate salts in ethanol, followed by reactive distillation to form succinate esters, is presented. Process simulation was performed for a range of plant capacities (13-55 million kg/yr SA) and SA fermentation titers (50-100 kg/m(3)). Economics were evaluated for a recovery system installed within an existing fermentation facility producing succinate salts at a cost of $0.66/kg SA. For a SA processing capacity of 54.9 million kg/yr and a titer of 100 kg/m(3) SA, the model predicts a capital investment of $75 million and a net processing cost of $1.85 per kg SA. Required selling price of diethyl succinate for a 30% annual return on investment is $1.57 per kg. Copyright © 2013 Elsevier Ltd. All rights reserved.

A comparison of the energy use of in situ product recovery techniques for the Acetone Butanol Ethanol fermentation.

PubMed

Outram, Victoria; Lalander, Carl-Axel; Lee, Jonathan G M; Davis, E Timothy; Harvey, Adam P

2016-11-01

The productivity of the Acetone Butanol Ethanol (ABE) fermentation can be significantly increased by application of various in situ product recovery (ISPR) techniques. There are numerous technically viable processes, but it is not clear which is the most economically viable in practice. There is little available information about the energy requirements and economics of ISPR for the ABE fermentation. This work compares various ISPR techniques based on UniSim process simulations of the ABE fermentation. The simulations provide information on the process energy and separation efficiency, which is fed into an economic assessment. Perstraction was the only technique to reduce the energy demand below that of a batch process, by approximately 5%. Perstraction also had the highest profit increase over a batch process, by 175%. However, perstraction is an immature technology, so would need significant development before being integrated to an industrial process. Copyright © 2016 Elsevier Ltd. All rights reserved.

Towards the Integration of Dark- and Photo-Fermentative Waste Treatment. 4. Repeated Batch Sequential Dark- and Photofermentation using Starch as Substrate

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

Laurinavichene, T. V.; Belokopytov, B. F.; Laurinavichius, K. S.

In this study we demonstrated the technical feasibility of a prolonged, sequential two-stage integrated process under a repeated batch mode of starch fermentation. In this durable scheme, the photobioreactor with purple bacteria in the second stage was fed directly with dark culture from the first stage without centrifugation, filtration, or sterilization (not demonstrated previously). After preliminary optimization, both the dark- and the photo-stages were performed under repeated batch modes with different process parameters. Continuous H{sub 2} production in this system was observed at a H{sub 2} yield of up to 1.4 and 3.9 mole mole{sup -1} hexose during the dark-more » and photo-stage, respectively (for a total of 5.3 mole mole{sup -1} hexose), and rates of 0.9 and 0.5 L L{sup -1} d{sup -1}, respectively. Prolonged repeated batch H{sub 2} production was maintained for up to 90 days in each stage and was rather stable under non-aseptic conditions. Potential for improvements in these results are discussed.« less