Effects of cinnamaldehyde and garlic oil on rumen microbial fermentation in a dual flow continuous culture.

Science.gov (United States)

Busquet, M; Calsamiglia, S; Ferret, A; Cardozo, P W; Kamel, C

2005-07-01

Eight continuous culture fermentors inoculated with ruminal liquor from heifers fed a 50:50 alfalfa hay:concentrate diet (17.6% crude protein, 28.0% neutral detergent fiber) were used in 3 replicated periods to study the effects of cinnamaldehyde (CIN) and garlic oil (GAR) on rumen microbial fermentation. Treatments were no additive (negative control); 1.25 mg/L (MON) and 12.5 mg/L (MON10) of the ionophore antibiotic monensin (positive control); 31.2 mg/L CIN (CIN) and 312 mg/L (CIN10) of CIN; and 31.2 mg/L GAR (GAR) and 312 mg/L (GAR10) of GAR (Allium sativa). The MON10 caused expected changes in microbial fermentation patterns (a decrease in fiber digestion, ammonia N concentration, and proportions of acetate and butyrate; an increase in the proportion of propionate; and a trend to increase small peptide plus AA N concentration). The CIN decreased the proportion of acetate and branch-chained volatile fatty acids (VFA) and increased the proportion of propionate; CIN10 decreased the proportion of acetate and increased the proportion of butyrate compared with the control. The GAR10 increased the proportion of propionate and butyrate and decreased the proportion of acetate and branch-chained VFA compared with the control. The GAR10 also increased the small peptide plus amino acid N concentration, although no effects were observed on large peptides or ammonia N concentrations. The CIN and GAR10 resulted in similar effects as monensin, with the exception of the effects on the molar proportion of butyrate, which suggests that they might have a different mode of action in affecting in vitro microbial fermentation.

Simulation and optimization of continuous extractive fermentation with recycle system

Science.gov (United States)

Widjaja, Tri; Altway, Ali; Rofiqah, Umi; Airlangga, Bramantyo

2017-05-01

Extractive fermentation is continuous fermentation method which is believed to be able to substitute conventional fermentation method (batch). The recovery system and ethanol refinery will be easier. Continuous process of fermentation will make the productivity increase although the unconverted sugar in continuous fermentation is still in high concentration. In order to make this process more efficient, the recycle process was used. Increasing recycle flow will enhance the probability of sugar to be re-fermented. However, this will make ethanol enter fermentation column. As a result, the accumulated ethanol will inhibit the growth of microorganism. This research aims to find optimum conditions of solvent to broth ratio (S:B) and recycle flow to fresh feed ratio in order to produce the best yield and productivity. This study employed optimization by Hooke Jeeves method using Matlab 7.8 software. The result indicated that optimum condition occured in S: B=2.615 and R: F=1.495 with yield = 50.2439 %.

Continuous fermentation of carbohydrate-containing liquids to alcohol

Energy Technology Data Exchange (ETDEWEB)

Moldenhauer, O; Lechner, R

1955-08-25

Rate of alcohol fermentation depends mostly on the biological state of the yeast. The process described avoids retardation during the final fermentation phase by increasing the concentration of yeast as the fermentation proceeds. The method is especially suitable for dilute carbohydrate solutions. Thus, to a solution containing 4% carbohydrates, 66 g pressed yeast was added. This mash was passed continuously through several fermentation vessels. The temperature was adjusted to 29 to 35 degrees according to the type of yeast. Before entering the next vessel, another portion of pressed yeast (66 g/1 of mash) is added. The yeast is recovered from the fermented mash by means of a yeast separator.

Continuous fermentation of carbohydrate-containing liquids to alcohol

Energy Technology Data Exchange (ETDEWEB)

Moldenhauer, O; Lechner, R

1955-08-29

Rate of alcohol fermentation depends mostly on the biological state of the yeast. The process described avoids retardation during the final fermentation phase by increasing the concentration of yeast as the fermentation proceeds. The method is especially suitable for dilute carbohydrate solutions. Thus, to a solution containing 4% carbohydrates, 66 g pressed yeast was added. This mash was passed continuously through several fermentation vessels. The temperature was adjusted to 29 to 35/sup 0/ according to the type of yeast. Before entering the next vessel, another portion of pressed yeast (66 g/l of mash) is added. The yeast is recovered from the fermented mash by means of a yeast separator.

Immobilized anaerobic fermentation for bio-fuel production by Clostridium co-culture.

Science.gov (United States)

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.

Multi-stage high cell continuous fermentation for high productivity and titer.

Science.gov (United States)

Chang, Ho Nam; Kim, Nag-Jong; Kang, Jongwon; Jeong, Chang Moon; Choi, Jin-dal-rae; Fei, Qiang; Kim, Byoung Jin; Kwon, Sunhoon; Lee, Sang Yup; Kim, Jungbae

2011-05-01

We carried out the first simulation on multi-stage continuous high cell density culture (MSC-HCDC) to show that the MSC-HCDC can achieve batch/fed-batch product titer with much higher productivity to the fed-batch productivity using published fermentation kinetics of lactic acid, penicillin and ethanol. The system under consideration consists of n-serially connected continuous stirred-tank reactors (CSTRs) with either hollow fiber cell recycling or cell immobilization for high cell-density culture. In each CSTR substrate supply and product removal are possible. Penicillin production is severely limited by glucose metabolite repression that requires multi-CSTR glucose feeding. An 8-stage C-HCDC lactic acid fermentation resulted in 212.9 g/L of titer and 10.6 g/L/h of productivity, corresponding to 101 and 429% of the comparable lactic acid fed-batch, respectively. The penicillin production model predicted 149% (0.085 g/L/h) of productivity in 8-stage C-HCDC with 40 g/L of cell density and 289% of productivity (0.165 g/L/h) in 7-stage C-HCDC with 60 g/L of cell density compared with referring batch cultivations. A 2-stage C-HCDC ethanol experimental run showed 107% titer and 257% productivity of the batch system having 88.8 g/L of titer and 3.7 g/L/h of productivity. MSC-HCDC can give much higher productivity than batch/fed-batch system, and yield a several percentage higher titer as well. The productivity ratio of MSC-HCDC over batch/fed-batch system is given as a multiplication of system dilution rate of MSC-HCDC and cycle time of batch/fed-batch system. We suggest MSC-HCDC as a new production platform for various fermentation products including monoclonal antibody.

Solid-state fermentation: a continuous process for fungal tannase production.

Science.gov (United States)

van de Lagemaat, J; Pyle, D L

2004-09-30

Truly continuous solid-state fermentations with operating times of 2-3 weeks were conducted in a prototype bioreactor for the production of fungal (Penicillium glabrum) tannase from a tannin-containing model substrate. Substantial quantities of the enzyme were synthesized throughout the operating periods and (imperfect) steady-state conditions seemed to be achieved soon after start-up of the fermentations. This demonstrated for the first time the possibility of conducting solid-state fermentations in the continuous mode and with a constant noninoculated feed. The operating variables and fermentation conditions in the bioreactor were sufficiently well predicted for the basic reinoculation concept to succeed. However, an incomplete understanding of the microbial mechanisms, the experimental system, and their interaction indicated the need for more research in this novel area of solid-state fermentation. Copyright 2004 Wiley Periodicals, Inc.

Development of a goat fermented milk with probiotics starter culture

Directory of Open Access Journals (Sweden)

Aldo Hernández-Monzón

2016-07-01

Full Text Available The goat milk for their multiple properties nutraceutical and for the high yield of their derived products, it represents an interesting commercial alternative for the elaboration of special fermented milk. At the present time the probiotics starter culture for their proven properties are used thoroughly in the elaboration of fermented milk. Keeping in mind these antecedents this work had as objective to develop a fermented milk of goat with characteristic probiotics, good acceptability and appropriate shelf life using the starter culture Lactobacillus casei, Lactobacillus acidophilus jointly with the starter culture of the yogurt. It was carried out a design of experiment of response surface (22 with the independent variables, starter culture dose (1.5 to 2.5% and the relationship of starter culture of yogurt: probiotics starter culture 1:3 at 1:5. As variable answers they took: the viability, the acidity and the sensorial indicators. The formulation selected with the best characteristics was conserved to temperature of 4 oC for the evaluation of the storage life. The best formulation was the 2% starter culture with a relationship of 1:4. The fermented milk was evaluated of “I like” and its viability was above the therapeutic minimum until the 21 days (log (UFC/ml of 8.8 at 7.0.

Breeding Strategy To Generate Robust Yeast Starter Cultures for Cocoa Pulp Fermentations

Science.gov (United States)

Meersman, Esther; Steensels, Jan; Paulus, Tinneke; Struyf, Nore; Saels, Veerle; Mathawan, Melissa; Koffi, Jean; Vrancken, Gino

2015-01-01

Cocoa pulp fermentation is a spontaneous process during which the natural microbiota present at cocoa farms is allowed to ferment the pulp surrounding cocoa beans. Because such spontaneous fermentations are inconsistent and contribute to product variability, there is growing interest in a microbial starter culture that could be used to inoculate cocoa pulp fermentations. Previous studies have revealed that many different fungi are recovered from different batches of spontaneous cocoa pulp fermentations, whereas the variation in the prokaryotic microbiome is much more limited. In this study, therefore, we aimed to develop a suitable yeast starter culture that is able to outcompete wild contaminants and consistently produce high-quality chocolate. Starting from specifically selected Saccharomyces cerevisiae strains, we developed robust hybrids with characteristics that allow them to efficiently ferment cocoa pulp, including improved temperature tolerance and fermentation capacity. We conducted several laboratory and field trials to show that these new hybrids often outperform their parental strains and are able to dominate spontaneous pilot scale fermentations, which results in much more consistent microbial profiles. Moreover, analysis of the resulting chocolate showed that some of the cocoa batches that were fermented with specific starter cultures yielded superior chocolate. Taken together, these results describe the development of robust yeast starter cultures for cocoa pulp fermentations that can contribute to improving the consistency and quality of commercial chocolate production. PMID:26150457

REDUCING WASTEWATER FROM CUCUMBER PICKLING PROCESS BY CONTROLLED CULTURE FERMENTATION

Science.gov (United States)

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. ...

Contamination of alcoholic molasses mashes in respect to continuous fermentation

Energy Technology Data Exchange (ETDEWEB)

Zvacek, O; Barta, J; Vintika, J

1957-01-01

Contamination (I) of molasses mashes during and after continuous alcohol fermentation was caused by species of Lactobacillus, belonging both to the hetero and homofermentative type. The latter types were not found in discontinuous fermentation. I affected considerably the content of residual sugar (II) in the fermented molasses mash, reaching in some cases zero values. II thus cannot be an objective criterion of the fermentation process.

Modeling of Clostridium tyrobutyricum for Butyric Acid Selectivity in Continuous Fermentation

Directory of Open Access Journals (Sweden)

Jianjun Du

2014-04-01

Full Text Available A mathematical model was developed to describe batch and continuous fermentation of glucose to organic acids with Clostridium tyrobutyricum. A modified Monod equation was used to describe cell growth, and a Luedeking-Piret equation was used to describe the production of butyric and acetic acids. Using the batch fermentation equations, models predicting butyric acid selectivity for continuous fermentation were also developed. The model showed that butyric acid production was a strong function of cell mass, while acetic acid production was a function of cell growth rate. Further, it was found that at high acetic acid concentrations, acetic acid was metabolized to butyric acid and that this conversion could be modeled. In batch fermentation, high butyric acid selectivity occurred at high initial cell or glucose concentrations. In continuous fermentation, decreased dilution rate improved selectivity; at a dilution rate of 0.028 h−1, the selectivity reached 95.8%. The model and experimental data showed that at total cell recycle, the butyric acid selectivity could reach 97.3%. This model could be used to optimize butyric acid production using C. tyrobutyricum in a continuous fermentation scheme. This is the first study that mathematically describes batch, steady state, and dynamic behavior of C. tyrobutyricum for butyric acid production.

Breeding Strategy To Generate Robust Yeast Starter Cultures for Cocoa Pulp Fermentations.

Science.gov (United States)

Meersman, Esther; Steensels, Jan; Paulus, Tinneke; Struyf, Nore; Saels, Veerle; Mathawan, Melissa; Koffi, Jean; Vrancken, Gino; Verstrepen, Kevin J

2015-09-01

Cocoa pulp fermentation is a spontaneous process during which the natural microbiota present at cocoa farms is allowed to ferment the pulp surrounding cocoa beans. Because such spontaneous fermentations are inconsistent and contribute to product variability, there is growing interest in a microbial starter culture that could be used to inoculate cocoa pulp fermentations. Previous studies have revealed that many different fungi are recovered from different batches of spontaneous cocoa pulp fermentations, whereas the variation in the prokaryotic microbiome is much more limited. In this study, therefore, we aimed to develop a suitable yeast starter culture that is able to outcompete wild contaminants and consistently produce high-quality chocolate. Starting from specifically selected Saccharomyces cerevisiae strains, we developed robust hybrids with characteristics that allow them to efficiently ferment cocoa pulp, including improved temperature tolerance and fermentation capacity. We conducted several laboratory and field trials to show that these new hybrids often outperform their parental strains and are able to dominate spontaneous pilot scale fermentations, which results in much more consistent microbial profiles. Moreover, analysis of the resulting chocolate showed that some of the cocoa batches that were fermented with specific starter cultures yielded superior chocolate. Taken together, these results describe the development of robust yeast starter cultures for cocoa pulp fermentations that can contribute to improving the consistency and quality of commercial chocolate production. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Modeling of Clostridium tyrobutyricum for Butyric Acid Selectivity in Continuous Fermentation

OpenAIRE

Du, Jianjun; McGraw, Amy; Hestekin, Jamie

2014-01-01

A mathematical model was developed to describe batch and continuous fermentation of glucose to organic acids with Clostridium tyrobutyricum. A modified Monod equation was used to describe cell growth, and a Luedeking-Piret equation was used to describe the production of butyric and acetic acids. Using the batch fermentation equations, models predicting butyric acid selectivity for continuous fermentation were also developed. The model showed that butyric acid production was a strong function ...

New generation biofuel from whey: Successive acidogenesis and alcoholic fermentation using immobilized cultures on γ-alumina

International Nuclear Information System (INIS)

Boura, Konstantina; Kandylis, Panagiotis; Bekatorou, Argyro; Kolliopoulos, Dionysios; Vasileiou, Dimitrios; Panas, Panayiotis; Kanellaki, Maria; Koutinas, Athanasios A.

2017-01-01

Highlights: • Successive continuous alcoholic fermentation and acidogenesis of whey. • UASB culture (acidogenesis) and kefir (alcoholic fermentation) fixed on γ-alumina. • Alcoholic fermentation-acidogenesis process led to 10-fold higher ethanol content. • Organic acids production was increased by 2.5-fold. • The process is promising for new generation ester-based biofuels from whey. - Abstract: Cheese whey exploitation in a biorefinery manner is proposed involving anaerobic acidogenesis by a UASB mixed anaerobic culture and alcoholic fermentation by kefir. Both cultures were immobilized on γ-alumina. The produced organic acids (OAs) and ethanol could be esterified to obtain a novel ester-based biofuel similar to biodiesel. During acidogenesis, lactic acid-type fermentation occurred leading to 12 g L"−"1 total OAs and 0.2 g L"−"1 ethanol. The fermented substrate was subsequently supplied to a second bioreactor with immobilized kefir, which increased the OAs content (15 g L"−"1), especially lactic acid, and slightly the ethanol concentration (0.3–0.4 g L"−"1). To further increase ethanol concentration, a second experiment was conducted supplying whey firstly to the immobilized kefir bioreactor and then pumping the effluent into the acidogenesis bioreactor, resulting in 40% increase of OAs and 10-fold higher ethanol content. The residual sugar was ∼50% of the initial whey lactose; consequently, future research could result to further increase of ethanol and OAs.

Omega-3 production by fermentation of Yarrowia lipolytica: From fed-batch to continuous.

Science.gov (United States)

Xie, Dongming; Miller, Edward; Sharpe, Pamela; Jackson, Ethel; Zhu, Quinn

2017-04-01

The omega-3 fatty acid, cis-5,8,11,14,17-eicosapentaenoic acid (C20:5; EPA) has wide-ranging benefits in improving heart health, immune function, and mental health. A sustainable source of EPA production through fermentation of metabolically engineered Yarrowia lipolytica has been developed. In this paper, key fed-batch fermentation conditions were identified to achieve 25% EPA in the yeast biomass, which is so far the highest EPA titer reported in the literature. Dynamic models of the EPA fermentation process were established for analyzing, optimizing, and scaling up the fermentation process. In addition, model simulations were used to develop a two-stage continuous process and compare to single-stage continuous and fed- batch processes. The two stage continuous process, which is equipped with a smaller growth fermentor (Stage 1) and a larger production fermentor (Stage 2), was found to be a superior process to achieve high titer, rate, and yield of EPA. A two-stage continuous fermentation experiment with Y. lipolytica strain Z7334 was designed using the model simulation and then tested in a 2 L and 5 L fermentation system for 1,008 h. Compared with the standard 2 L fed-batch process, the two-stage continuous fermentation process improved the overall EPA productivity by 80% and EPA concentration in the fermenter by 40% while achieving comparable EPA titer in biomass and similar conversion yield from glucose. During the long-term experiment it was also found that the Y. lipolytica strain evolved to reduce byproduct and increase lipid production. This is one of the few continuous fermentation examples that demonstrated improved productivity and concentration of a final product with similar conversion yield compared with a fed-batch process. This paper suggests the two-stage continuous fermentation could be an effective process to achieve improved production of omega-3 and other fermentation products where non-growth or partially growth associated kinetics

Manioc alcohol by continuous fermentation

Energy Technology Data Exchange (ETDEWEB)

Del Bianco, V; de Queiroz Araujo, N; Miceli, A; Souza e Silva, P C; da Silva Burle, J A

1976-01-01

EtOH was produced from dry cassava meal by first obtaining a glucose syrup by enzymic action, then fermenting the syrup with yeast. Bacillus subtilis amylase and Aspergillus awamori amyloglucosidase were prepared by growing the organisms on cassava meal. Both enzymes were used to saccharify the cassava starch to syrup. Saccharomyces cervisiae ATCC 1133 was then used in a continuous process to produce EtOH.

Kinetic model of continuous ethanol fermentation in closed-circulating process with pervaporation membrane bioreactor by Saccharomyces cerevisiae.

Science.gov (United States)

Fan, Senqing; Chen, Shiping; Tang, Xiaoyu; Xiao, Zeyi; Deng, Qing; Yao, Peina; Sun, Zhaopeng; Zhang, Yan; Chen, Chunyan

2015-02-01

Unstructured kinetic models were proposed to describe the principal kinetics involved in ethanol fermentation in a continuous and closed-circulating fermentation (CCCF) process with a pervaporation membrane bioreactor. After ethanol was removed in situ from the broth by the membrane pervaporation, the secondary metabolites accumulated in the broth became the inhibitors to cell growth. The cell death rate related to the deterioration of the culture environment was described as a function of the cell concentration and fermentation time. In CCCF process, 609.8 g L(-1) and 750.1 g L(-1) of ethanol production were obtained in the first run and second run, respectively. The modified Gompertz model, correlating the ethanol production with the fermentation period, could be used to describe the ethanol production during CCCF process. The fitting results by the models showed good agreement with the experimental data. These models could be employed for the CCCF process technology development for ethanol fermentation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of corn inclusion on soybean hull-based diet digestibility and growth performance in continuous culture fermenters and beef cattle.

Science.gov (United States)

Russell, J R; Sexten, W J; Kerley, M S

2016-07-01

Two experiments were conducted using soybean hull (SH) diets with increasing corn proportions to determine increasing corn inclusion effects on fermentation characteristics, diet digestibility, and feedlot performance. The hypothesis was that fiber digestibility would quadratically respond to starch proportion in the diet with a break point where starch inclusion improved fiber digestion and feedlot performance. Proportionately, the diets contained 100:0 (SH100), 90:10 (SH90), 80:20 (SH80), 60:40 (SH60), or 20:80 SH:corn (SH20). In Exp. 1, diets were randomly distributed over 24 continuous culture fermenters and fed for 7 d. In Exp. 2, forty steers (347 ± 29 kg BW) and 50 heifers (374 ± 24 kg BW) were blocked by gender, stratified by BW, and distributed across diets. Cattle were fed for 70 d with titanium dioxide included in the diet for the final 14 d and fecal samples collected to measure digestibility. Individual DMI was measured using GrowSafe Feed Intake system. Data were analyzed using the MIXED procedure of SAS with diet evaluated as the fixed effect. In Exp. 1, NDF digestibility (NDFd) linearly decreased ( = 0.04) and ADF digestibility (ADFd) tended to linearly decrease ( = 0.09) as corn increased. Dry matter digestibility (DMd) was cubic ( = 0.01) and OM digestibility (OMd) was quadratic ( = 0.03), and among the 4 SH-based diets, DMd and OMd were greatest for SH90. Acetate:propionate ratio and pH were quadratic ( digestibility decreased as corn inclusion increased. However, based on continuous culture digestibility and VFA values as well as feedlot digestibility and performance, optimal corn inclusion for growth and diet utilization in the 4 SH-based diets fell between SH80 and SH90, or 0.4 and 0.2% BW corn supplementation. In this study, providing 0.4% BW corn supplementation in fiber-based diets (SH80) provided greater improvement in performance compared with 0.2% BW corn supplementation (SH90).

Process for producing fuel grade ethanol by continuous fermentation, solvent extraction and alcohol separation

Science.gov (United States)

Tedder, Daniel W.

1985-05-14

Alcohol substantially free of water is prepared by continuously fermenting a fermentable biomass feedstock in a fermentation unit, thereby forming an aqueous fermentation liquor containing alcohol and microorganisms. Continuously extracting a portion of alcohol from said fermentation liquor with an organic solvent system containing an extractant for said alcohol, thereby forming an alcohol-organic solvent extract phase and an aqueous raffinate. Said alcohol is separated from said alcohol-organic solvent phase. A raffinate comprising microorganisms and unextracted alcohol is returned to the fermentation unit.

Continuous dark fermentative hydrogen production by mesophilic microflora: Principles and progress

Energy Technology Data Exchange (ETDEWEB)

Hawkes, Freda R.; Hussy, Ines; Kyazze, Godfrey; Dinsdale, Richard; Hawkes, Dennis L. [School of Applied Sciences, University of Glamorgan, Pontypridd RCT CF37 1DL (United Kingdom)

2007-02-15

Continuous, dark fermentative hydrogen production technology using mixed microflora at mesophilic temperatures may be suitable for commercial development. Clostridial-based cultures from natural sources have been widely used, but more information on the need for heat treatment of inocula and conditions leading to germination and sporulation are required. The amount of nutrients given in the literature vary widely. Hydrogen production is reported to proceed without methane production in the reactor in the pH range 4.5-6.7, with hydraulic retention times optimally between a few hours and 3 days depending on substrate. Higher substrate concentrations should be more energy-efficient but there are product inhibition limitations, for example from unionised butyric acid. Inhibition by H{sub 2} can be reduced by stirring, sparging or extraction through membranes. Of the reactor types investigated, while granules have the best performance with soluble substrate, for particulate feedstock biofilm reactors or continuous stirred tank reactors may be most successful. A second stage is required to utilise the fermentation end products which, when cost-effective reactors are developed, may be photofermentation or microbial fuel cell technologies. Anaerobic digestion is a currently-available technology and the two-stage process is reported to give greater conversion efficiency than anaerobic digestion alone. (author)

Modeling of Clostridium t yrobutyricum for Butyric Acid Selectivity in Continuous Fermentation

OpenAIRE

Jianjun Du; Amy McGraw; Jamie A. Hestekin

2014-01-01

A mathematical model was developed to describe batch and continuous fermentation of glucose to organic acids with Clostridium tyrobutyricum . A modified Monod equation was used to describe cell growth, and a Luedeking-Piret equation was used to describe the production of butyric and acetic acids. Using the batch fermentation equations, models predicting butyric acid selectivity for continuous fermentation were also developed. The model showed that butyric acid production was a strong function...

Production of tea vinegar by batch and semicontinuous fermentation

OpenAIRE

Kaur, Pardeep; Kocher, G. S.; Phutela, R. P.

2010-01-01

The fermented tea vinegar combines the beneficial properties of tea and vinegar. The complete fermentation takes 4 to 5 weeks in a batch culture and thus can be shortened by semi continuous/ continuous fermentation using immobilized bacterial cells. In the present study, alcoholic fermentation of 1.0 and 1.5% tea infusions using Saccharomyces cerevisae G was carried out that resulted in 84.3 and 84.8% fermentation efficiency (FE) respectively. The batch vinegar fermentation of these wines wit...

Impact of mixed Torulaspora delbrueckii-Saccharomyces cerevisiae culture on high-sugar fermentation.

Science.gov (United States)

Bely, Marina; Stoeckle, Philippe; Masneuf-Pomarède, Isabelle; Dubourdieu, Denis

2008-03-20

Conventional wine yeasts produce high concentrations of volatile acidity, mainly acetic acid, during high-sugar fermentation. This alcoholic fermentation by-product is highly detrimental to wine quality and, in some cases, levels may even exceed legal limits. In this study, a non-conventional species, Torulaspora delbrueckii, was used, in pure cultures and mixed with Saccharomyces cerevisiae yeast, to ferment botrytized musts. Fermentation rate, biomass growth, and the formation of volatile acidity, acetaldehyde, and glycerol were considered. This study demonstrated that T. delbrueckii, often described as a low acetic producer under standard conditions, retained this quality even in a high-sugar medium. Unlike S. cerevisiae, this species did not respond to the hyper-osmotic medium by increasing acetic production as soon as it is inoculated into the must. Nevertheless, this yeast produced low ethanol and biomass yields, and the fermentation was sluggish. As a result, T. delbrueckii fermentations do not reach the required ethanol content (14%vol.), although this species can survive at this concentration. A mixed culture of T. delbrueckii and S. cerevisiae was the best combination for improving the analytical profile of sweet wine, particularly volatile acidity and acetaldehyde production. A mixed T. delbrueckii/S. cerevisiae culture at a 20:1 ratio produced 53% less in volatile acidity and 60% less acetaldehyde than a pure culture of S. cerevisiae. Inoculating S. cerevisiae after 5 days' fermentation by T. delbrueckii had less effect on volatile acidity and acetaldehyde production and resulted in stuck fermentation. These results contribute to a better understanding of the behaviour of non-Saccharomyces and their potential application in wine industry.

STARTER CULTURES COMPOSITIONS WITH PROBIOTICS FOR FERMENTED MILK PRODUCTS AND COSMETICS

Directory of Open Access Journals (Sweden)

N. Tkachenko

2018-04-01

Full Text Available The expediency of optimization of starter cultures composition of mixed cultures Lactococcus sp. and mixed cultures Bifidobacterium bifidum BB 01 + Bifidobacterium longum BL 01 + Bifidobacterium breve BR 01 for the manufacture of fermented milk products and cosmetics for teenagers and people under the age of 40-45 years with probiotics has been substantiated.The value of titratable acidity, number of viable cells of bifidobacteria has been determined, as well as the most probable number of lactobacterium in fermented probiotic clots obtained with different ratios of mixed cultures Lactococcus sp. and mixed cultures of Bifidobacterium sp. in starter cultures compositions (the initial concentration of the mixed cultures (MC Lactococcus sp. and MC Bifidobacterium sp. varied within the range of 1×105 – 1×106 CFU/cm3 of the inoculated milk, enriched with fructose as a growth factor of bifidobacteria. The high content of probiotics and the lowest values of titratable acidity are typical of the fermented milk clots obtained using starter cultures composition with a ratio of MC Lactococcus sp. : MC Bifidobacterium sp. 1 : 10. The maximum number of lactococci viable cells is observed in clots obtained using starter cultures composition with the initial ratio of MC Lactococcus sp. : MC Bifidobacterium sp. 10 : 1. The optimum ratio of MC Lactococcus sp. and MC Bifidobacterium sp. – 1 : 10 has been established (initial concentration of the cultures at inoculation – 1×105 and 1×106 CFU/cm3, respectively for the production of fermented milk products and cosmetics with probiotics, where the maximum value of the quality aggregated factor – 7, 12 is noted.It is shown that a fermented probiotic milk clots obtained using starter cultures composition with an optimum ratio of cultures of lacto- and bifidobacteria (1 : 10 have good sensory characteristics, contain a high number of viable cells of bifidobacteria and lactobacteria – (9,15±0,14×109 and

Stable acetate production in extreme-thermophilic (70°C) mixed culture fermentation by selective enrichment of hydrogenotrophic methanogens

Science.gov (United States)

Zhang, Fang; Zhang, Yan; Ding, Jing; Dai, Kun; van Loosdrecht, Mark C. M.; Zeng, Raymond J.

2014-06-01

The control of metabolite production is difficult in mixed culture fermentation. This is particularly related to hydrogen inhibition. In this work, hydrogenotrophic methanogens were selectively enriched to reduce the hydrogen partial pressure and to realize efficient acetate production in extreme-thermophilic (70°C) mixed culture fermentation. The continuous stirred tank reactor (CSTR) was stable operated during 100 days, in which acetate accounted for more than 90% of metabolites in liquid solutions. The yields of acetate, methane and biomass in CSTR were 1.5 +/- 0.06, 1.0 +/- 0.13 and 0.4 +/- 0.05 mol/mol glucose, respectively, close to the theoretical expected values. The CSTR effluent was stable and no further conversion occurred when incubated for 14 days in a batch reactor. In fed-batch experiments, acetate could be produced up to 34.4 g/L, significantly higher than observed in common hydrogen producing fermentations. Acetate also accounted for more than 90% of soluble products formed in these fed-batch fermentations. The microbial community analysis revealed hydrogenotrophic methanogens (mainly Methanothermobacter thermautotrophicus and Methanobacterium thermoaggregans) as 98% of Archaea, confirming that high temperature will select hydrogenotrophic methanogens over aceticlastic methanogens effectively. This work demonstrated a potential application to effectively produce acetate as a value chemical and methane as an energy gas together via mixed culture fermentation.

Operation of a two-stage continuous fermentation process producing hydrogen and methane from artificial food wastes

Energy Technology Data Exchange (ETDEWEB)

Nagai, Kohki; Mizuno, Shiho; Umeda, Yoshito; Sakka, Makiko [Toho Gas Co., Ltd. (Japan); Osaka, Noriko [Tokyo Gas Co. Ltd. (Japan); Sakka, Kazuo [Mie Univ. (Japan)

2010-07-01

An anaerobic two-stage continuous fermentation process with combined thermophilic hydrogenogenic and methanogenic stages (two-stage fermentation process) was applied to artificial food wastes on a laboratory scale. In this report, organic loading rate (OLR) conditions for hydrogen fermentation were optimized before operating the two-stage fermentation process. The OLR was set at 11.2, 24.3, 35.2, 45.6, 56.1, and 67.3 g-COD{sub cr} L{sup -1} day{sup -1} with a temperature of 60 C, pH5.5 and 5.0% total solids. As a result, approximately 1.8-2.0 mol-H{sub 2} mol-hexose{sup -1} was obtained at the OLR of 11.2-56.1 g-COD{sub cr} L{sup -1} day{sup -1}. In contrast, it was inferred that the hydrogen yield at the OLR of 67.3 g-COD{sub cr} L{sup -1} day{sup -1} decreased because of an increase in lactate concentration in the culture medium. The performance of the two-stage fermentation process was also evaluated over three months. The hydraulic retention time (HRT) of methane fermentation was able to be shortened 5.0 days (under OLR 12.4 g-COD{sub cr} L{sup -1} day{sup -1} conditions) when the OLR of hydrogen fermentation was 44.0 g-COD{sub cr} L{sup -1} day{sup -1}, and the average gasification efficiency of the two-stage fermentation process was 81% at the time. (orig.)

Dynamics of Cocoa Bean Pulp Degradation during Cocoa Bean Fermentation: Effects of Yeast Starter Culture Addition

Directory of Open Access Journals (Sweden)

Laras Cempaka

2014-07-01

Full Text Available Fermentation is a crucial step in the post-harvest processing of cocoa beans. This process comprises mixed culture microbial activities on the cocoa bean pulp, producing metabolites that act as important precursors for cocoa flavour development. Variations in the microbial population dynamics during the fermentation process may induce changes in the overall process. Thus, the introduction of a specific microbial starter culture may improve the quality of the fermentation. This article discusses the effects ofthe addition of Saccharomyces cerevisae var. Chevalieri starter culture on cocoa bean fermentation. The dynamics in the yeast concentration, sugary pulp compounds and metabolic products were measured during fermentation. The alterations in the dynamic metabolite profile were significant, although only a slight difference was observed in the yeast population. A higher fermentation index was measured for the cocoa bean fermentation with yeast starter culture, 1.13 compared to 0.84. In conclusion, this method can potentially be applied to shorten the cocoa bean fermentation time.

Continuous production of ethanol from hexoses and pentoses using immobilized mixed cultures of Escherichia coli strains

Science.gov (United States)

Unrean, Pornkamol; Srienc, Friedrich

2010-01-01

We have developed highly efficient ethanologenic E. coli strains that selectively consume pentoses and/or hexoses. Mixed cultures of these strains can be used to selectively adjust the sugar utilization kinetics in ethanol fermentations. Based on the kinetics of sugar utilization, we have designed and implemented an immobilized cell system for the optimized continuous conversion of sugars into ethanol. The results confirm that immobilized mixed cultures support a simultaneous conversion of hexoses and pentoses into ethanol at high yield and at a faster rate than immobilized homogenous cells. Continuous ethanol production has been maintained for several weeks at high productivity with near complete sugar utilization. The control of sugar utilization using immobilized mixed cultures can be adapted to any composition of hexoses and pentoses by adjusting the strain distribution of immobilized cells. The approach, therefore, holds promise for ethanol fermentation from lignocellulosic hydrolysates where the feedstock varies in sugar composition. PMID:20699108

On-line monitoring of important organoleptic methyl-branched aldehydes during batch fermentation of starter culture Staphylococcus xylosus reveal new insight into their production in a model fermentation

DEFF Research Database (Denmark)

de Vos Petersen, Christian; Beck, Hans Christian; Lauritsen, Frants R

2004-01-01

A small fermentor (55 mL) was directly interfaced to a membrane inlet mass spectrometer for continuous on-line monitoring of oxygen and volatile metabolites during batch fermentations of the starter culture Staphylococcus xylosus. Using this technique, we were able to correlate production...... of a longer aerobic growth period. Growing S. xylosus under conditions resembling those in a fermented sausage revealed that NaCl (5%) increased aldehyde production considerably, whereas KNO(3) (0.03%) or NaNO(2) (0.03%) had little effect. A lowering of pH from 7.2 to 6.0 reduced cell density, but had a minor...

Inoculated fermentation of green olives with potential probiotic Lactobacillus pentosus and Lactobacillus plantarum starter cultures isolated from industrially fermented olives.

Science.gov (United States)

Blana, Vasiliki A; Grounta, Athena; Tassou, Chrysoula C; Nychas, George-John E; Panagou, Efstathios Z

2014-04-01

The performance of two strains of lactic acid bacteria (LAB), namely Lactobacillus pentosus B281 and Lactobacillus plantarum B282, previously isolated from industrially fermented table olives and screened in vitro for probiotic potential, was investigated as starter cultures in Spanish style fermentation of cv. Halkidiki green olives. Fermentation was undertaken at room temperature in two different initial salt concentrations (8% and 10%, w/v, NaCl) in the brines. The strains were inoculated as single and combined cultures and the dynamics of their population on the surface of olives was monitored for a period of 114 days. The survival of inoculated strains on olives was determined using Pulsed Field Gel Electrophoresis (PFGE). Both probiotic strains successfully colonized the olive surface at populations ranged from 6.0 to 7.0 log CFU/g throughout fermentation. PFGE analysis revealed that L. pentosus B281 presented higher colonization in both salt levels at the end of fermentation (81.2% and 93.3% in 8% and 10% NaCl brines, respectively). For L. plantarum B282 a high survival rate (83.3%) was observed in 8% NaCl brines, but in 10% NaCl the strain could not colonize the surface of olives. L. pentosus B281 also dominated over L. plantarum B282 in inoculated fermentations when the two strains were used as combined culture. The biochemical profile (pH, organic acids, volatile compounds) attained during fermentation and the sensory analysis of the final product indicated a typical lactic acid fermentation process of green olives. Copyright © 2013 Elsevier Ltd. All rights reserved.

Use of Protein Hydrolysates in Industrial Starter Culture Fermentations

Science.gov (United States)

Ummadi, Madhavi (Soni); Curic-Bawden, Mirjana

Lactic acid bacteria (LAB) have been used as starter cultures for fermenting foods long before the importance of microorganisms were recognized. The most important group of LAB are the lactococci, lactobacilli, streptococci, and pediococci. Additionally, bifidobacteria have been included as a probiotic, providing added value to the product. Since the genera involved are so diverse, the nutritional requirements (energy, carbon and nitrogen sources) differ significantly between and within species. Designing an optimum fermentation medium for production of active and vigorous LAB starter cultures and probiotics requires selecting the right raw ingredients, especially protein hydrolysates that can provide adequate nutrients for growth and viability. This chapter attempts to describe the application of various commercial protein hydrolysates used for production of dairy and meat starter cultures, with special emphasis on meeting the nitrogen requirements of industrially important LAB species.

Evaluation of soymilk fermentation with a lactic culture

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Martha Cecilia Quicazán

2001-07-01

Full Text Available Soymilk, the protein slurry extracted in water from soybeans, obtained by means of a process tested previously at ICTA (the National University of Colombia's Institute of Food Science and Technology, was fermented by using a thermophyllic lactic culture consisting of L delbrueckii ss. bulgaricus, L. delbrueckii ss. lactis and S. salivarius ss. thermophilus. The soymilk composition was standardised (before fermentation, regarding solids and protein contení, by means of Brix0 as process variable. Soymilk was fermented by applying those same basic operations followed in cow milk fermentation. Acidification was assessed by evaluating pH, titrable acidity and organic acid production during the process by HPLC in an ionic exclusion column. Reologyc property modification was studied and compared with that for cow milk. It was proved that, despite the absence of lactose as substrate, soymilk acidification during this process can be explained by lactic acid production and that soymilk solid content influences acid production and changes in viscosity.

Development of starter culture for improved processing of Lafun, an African fermented cassava food product

DEFF Research Database (Denmark)

Padonou, S.W.; Nielsen, Dennis Sandris; Akissoe, N.H.

2010-01-01

AIMS: To select appropriate micro-organisms to be used as starter culture for reliable and reproducible fermentation of Lafun. METHODS AND RESULTS: A total of 22 cultures consisting of yeast, lactic acid bacteria (LAB) and Bacillus cereus strains predominant in traditionally fermented cassava...... during Lafun processing were tested as potential starter cultures. In an initial screening, Saccharomyces cerevisiae 2Y48P22, Lactobacillus fermentum 2L48P21, Lactobacillus plantarum 1L48P35 and B. cereus 2B24P31 were found to be the most promising of the cultures and were subsequently tested...... in different combinations as mixed starter cultures to ferment submerged cassava roots. Saccharomyces cerevisiae, inoculated singly or combined with B. cereus, gave the softest cassava root after 48 h of fermentation according to determination of compression profile and stress at fracture. Overall, sensory...

Effect of lactic acid bacteria starter culture fermentation of cassava ...

African Journals Online (AJOL)

The effects of lactic acid fermentation of cassava on the chemical and sensory characteristic of fufu flour were investigated. Two strains of Lactobacillus plantarum were used as starter cultures for the fermentation of cassava to fufu for 96 h. The resultant wet fufu samples were dried at 65oC in a cabinet dryer for 48 h and ...

Screening of penicillium species and optimisation of culture conditions for the production of ergot alkaloids using surface culture fermentation process

International Nuclear Information System (INIS)

Shahid, M.G.

2015-01-01

Abstract. The present study deals with the screening of fungal species and suitable fermentation medium for the production of ergot alkaloids. Various species of genus Penicillium were grown on different fermentation media by employing surface culture fermentation technique to achieve the most suitable medium and the best Penicillium sp. The results showed that medium M5 gave maximum yield with Penicillium commune. Different culture conditions such as effect of different carbon and nitrogen sources, their concentration levels, different pH values and sizes of inoculum on the production of ergot alkaloids were also studied to improve the yield. Maximum production of ergot alkaloids (4.32 mg/L) was achieved with 15 mL spore suspension at pH 5 in fermentation medium containing 35% (w/v) sucrose. All these results indicate that culture conditions are very much crucial to improve the yield of ergot alkaloids produced by Penicillium commune through surface culture process. (author)

Reduction of Biogenic Amines during Miso Fermentation by Lactobacillus plantarum as a Starter Culture.

Science.gov (United States)

Lee, Yi-Chen; Kung, Hsien-Feng; Huang, Ya-Ling; Wu, Chien-Hui; Huang, Yu-Ru; Tsai, Yung-Hsiang

2016-09-01

Lactobacillus plantarum D-103 isolated from a miso product that possesses amine-degrading activity was used as a starter culture in miso fermentation (25°C for 120 days) in this study. The salt content in control samples (without starter culture) and inoculated samples (inoculated with L. plantarum D-103) remained constant at 10.4% of the original salt concentration throughout fermentation, whereas the pH value decreased from 6.2 to 4.6 during fermentation. The inoculated samples had significantly lower (P < 0.05) levels of total volatile basic nitrogen than control samples after 40 days of fermentation. After 120 days of fermentation, the histamine and overall biogenic amine contents in inoculated samples were reduced by 58 and 27%, respectively, compared with control samples. To our knowledge, this is the first report to demonstrate that application of a starter culture with amine-degrading activity in miso products was effective in reducing the accumulation of biogenic amines.

Continuous butyric acid fermentation coupled with REED technology for enhanced productivity

DEFF Research Database (Denmark)

Baroi, George Nabin; Skiadas, Ioannis; Westermann, Peter

strains, C.tyrobutyricum seems the most promising for biological production of butyric acid as it is characterised by higher selectivity and higher tolerance to butyric acid. However, studies on fermentative butyric production from lignocellulosic biomasses are scarce in the international literature...... of continuous fermentation mode and in-situ acids removal by Reverse Enhanced Electro Dialysis (REED) resulted to enhanced sugars consumption rates when 60% PHWS was fermented. Specifically, glucose and xylose consumption rate increased by a factor of 6 and 39, respectively, while butyric acid productivity...

Bioprocess Intensification of Beer Fermentation Using Immobilised Cells

Science.gov (United States)

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.

Linearizing control of continuous anaerobic fermentation processes

Energy Technology Data Exchange (ETDEWEB)

Babary, J.P. [Centre National d`Etudes Spatiales (CNES), 31 - Toulouse (France). Laboratoire d`Analyse et d`Architecture des Systemes; Simeonov, I. [Institute of Microbiology, Bulgarian Academy of Sciences (Bulgaria); Ljubenova, V. [Institute of Control and System Research, BAS (Country unknown/Code not available); Dochain, D. [Universite Catholique de Louvain (UCL), Louvain-la-Neuve (Belgium)

1997-09-01

Biotechnological processes (BTP) involve living organisms. In the anaerobic fermentation (biogas production process) the organic matter is mineralized by microorganisms into biogas (methane and carbon dioxide) in the absence of oxygen. The biogas is an additional energy source. Generally this process is carried out as a continuous BTP. It has been widely used in life process and has been confirmed as a promising method of solving some energy and ecological problems in the agriculture and industry. Because of the very restrictive on-line information the control of this process in continuous mode is often reduced to control of the biogas production rate or the concentration of the polluting organic matter (de-pollution control) at a desired value in the presence of some perturbations. Investigations show that classical linear controllers have good performances only in the linear zone of the strongly non-linear input-output characteristics. More sophisticated robust and with variable structure (VSC) controllers are studied. Due to the strongly non-linear dynamics of the process the performances of the closed loop system may be degrading in this case. The aim of this paper is to investigate different linearizing algorithms for control of a continuous non-linear methane fermentation process using the dilution rate as a control action and taking into account some practical implementation aspects. (authors) 8 refs.

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

Science.gov (United States)

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.

Model based Control of a Continuous Yeast Fermentation

DEFF Research Database (Denmark)

Andersen, Maria Yolanda; Brabrand, Henrik; Jørgensen, Sten Bay

1991-01-01

Control of a continuous fermentation with Saccharomyces cerevisiae is performed by manipulation of the feed flow rate using an ethanol measurement in the exit gas The process is controlled at the critical dilution rate with a low ethanol concentration of 40-50 mg/l. A standard PI controller is able...

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

Science.gov (United States)

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.

Lactobacillus plantarum (KACC 92189) as a Potential Probiotic Starter Culture for Quality Improvement of Fermented Sausages

Science.gov (United States)

2018-01-01

This study was conducted to evaluate the effects of fermenting temperature on the applicability of Lactobacillus plantarum for production of fermented sausages as starter cultures, and its applicable efficiency was also compared with those inoculated with commercial starter culture or non-inoculated control. The L. plantarum isolated from a naturally-fermented meat, identified by 16S rDNA sequencing and again identified by de novo Assembly Analysis method was used as a starter culture. Six treatments: 3 with L. plantarum at different fermenting temperatures (20, 25 and 30°C), and other 3 treatments (1 with commercial starter culture, 1 with its mixture with L. plantarum and 1 non-inoculated control) fermented under the same conditions (25°C) were prepared. Results revealed that the fermenting temperature considerably affected the pH change in samples added with L. plantarum; the highest pH drop rate (1.57 unit) was obtained on the samples fermented at 30°C, followed by those at 25°C (1.3 unit) and 20°C (0.99 unit) after 4 days fermentation. Increasing the temperature up to 30°C resulted in significantly lower spoilage bacteria count (5.15 log CFU/g) and lipid oxidation level in the products inoculated with L. plantarum. The sensory analysis also showed that the samples added with L. plantarum at 30°C had significantly higher odor, taste and acceptability scores than those fermented at lower temperatures. Under the same processing condition, although the L. plantarum showed slightly lower acidification than the commercial starter culture, however, it significantly improved the eating quality of the product. PMID:29725237

Protein improvement in Gari by the use of pure cultures of microorganisms involved in the natural fermentation process.

Science.gov (United States)

Ahaotu, I; Ogueke, C C; Owuamanam, C I; Ahaotu, N N; Nwosu, J N

2011-10-15

The ability of microorganisms involved in cassava mash fermentation to produce and improve protein value by these microorganisms during fermentation was studied. Standard microbiological procedures were used to isolate, identify and determine the numbers of the organisms. Alcaligenes faecalis, Lactobacillus plantarum, Bacillus subtilis, Leuconostoc cremoris, Aspergillus niger, A. tamari, Geotrichum candidum and Penicillium expansum were isolated and identified from cassava waste water while standard analytical methods were used to determine the ability of the isolates to produce linamarase and the proximate composition, pH and titrable acidity of the fermenting mash. The linamarase activity of the isolates ranged from 0.0416 to 0.2618 micromol mL(-1) nmol(-1). Bacillus subtilis, A. niger, A. tamari and P. expansum did not express any activity for the enzyme. Protein content of mash fermented with mixed fungal culture had the highest protein value (15.4 mg/g/dry matter) while the raw cassava had the least value (2.37 mg/g/dry matter). The naturally fermented sample had the least value for the fermented samples (3.2 mg/g/dry matter). Carbohydrate and fat contents of naturally fermented sample were higher than values obtained from the other fermented samples. Microbial numbers of the sample fermented with mixed bacterial culture was highest and got to their peak at 48 h (57 x 10(8) cfu g(-1)). pH decreased with increase in fermentation time with the mash fermented by the mixed culture of fungi having the lowest pH of 4.05 at the end of fermentation. Titrable acidity increased with increase in fermentation time with the highest value of 1.32% at 96 h of fermentation produced by the mixed culture of fungi. Thus fermentation with the pure cultures significantly increased the protein content of mash.

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.

Science.gov (United States)

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.

Co-fermentation of cellobiose and xylose by mixed culture of recombinant Saccharomyces cerevisiae and kinetic modeling.

Science.gov (United States)

Chen, Yingying; Wu, Ying; Zhu, Baotong; Zhang, Guanyu; Wei, Na

2018-01-01

Efficient conversion of cellulosic sugars in cellulosic hydrolysates is important for economically viable production of biofuels from lignocellulosic biomass, but the goal remains a critical challenge. The present study reports a new approach for simultaneous fermentation of cellobiose and xylose by using the co-culture consisting of recombinant Saccharomyces cerevisiae specialist strains. The co-culture system can provide competitive advantage of modularity compared to the single culture system and can be tuned to deal with fluctuations in feedstock composition to achieve robust and cost-effective biofuel production. This study characterized fermentation kinetics of the recombinant cellobiose-consuming S. cerevisiae strain EJ2, xylose-consuming S. cerevisiae strain SR8, and their co-culture. The motivation for kinetic modeling was to provide guidance and prediction of using the co-culture system for simultaneous fermentation of mixed sugars with adjustable biomass of each specialist strain under different substrate concentrations. The kinetic model for the co-culture system was developed based on the pure culture models and incorporated the effects of product inhibition, initial substrate concentration and inoculum size. The model simulations were validated by results from independent fermentation experiments under different substrate conditions, and good agreement was found between model predictions and experimental data from batch fermentation of cellobiose, xylose and their mixtures. Additionally, with the guidance of model prediction, simultaneous co-fermentation of 60 g/L cellobiose and 20 g/L xylose was achieved with the initial cell densities of 0.45 g dry cell weight /L for EJ2 and 0.9 g dry cell weight /L SR8. The results demonstrated that the kinetic modeling could be used to guide the design and optimization of yeast co-culture conditions for achieving simultaneous fermentation of cellobiose and xylose with improved ethanol productivity, which is

Effects of Static or Oscillating Dietary Crude Protein Levels on Fermentation Dynamics of Beef Cattle Diets Using a Dual-Flow Continuous Culture System.

Directory of Open Access Journals (Sweden)

Paloma de Melo Amaral

Full Text Available The objective of this study was to evaluate the effects of increasing dietary crude protein (CP levels and also comparing the effects of static versus oscillating dietary CP on ruminal nutrient digestibility, ruminal fermentation, nitrogen (N metabolism, and microbial efficiency in beef cattle diets using a dual-flow continuous culture system. Eight fermenters (1,223 ± 21 mL were used in a replicated 4 x 4 Latin square design with periods lasting 12 d each (8 d for adaptation and 4 d for sampling. Dietary treatments were: 1 10% CP, 2 12% CP, 3 14% CP, and 4 10 and 14% CP diets oscillating at 48-h intervals. Experimental diets consisted of 50% orchard hay and 50% concentrate. Fermenters were fed 72 g/d and solid and liquid dilution rates were adjusted to 5.5 and 11%/h, respectively. Data were analyzed using the MIXED procedure in SAS with α = 0.05. Apparent and true ruminal digestibilities of dry matter and organic matter were not affected (P > 0.05 by increasing dietary CP, nor by oscillating dietary CP. Total volatile fatty acids concentration and molar proportions of acetate, propionate, butyrate, valerate, iso-butyrate and iso-valerate were not affected (P > 0.05 by increasing or oscillating dietary CP. Ruminal NH3-N concentration increased linearly (P 0.05. However, there was a quadratic effect (P < 0.05 for these variables when dietary CP was increased. These results indicate that either ruminal microorganisms do not respond to oscillating CP levels or are capable of coping with 48-h periods of undernourishment.

Continuous fermentative hydrogen production in different process conditions

Energy Technology Data Exchange (ETDEWEB)

Nasirian, N. [Islamic Azad Univ., Shoushtar (Iran, Islamic Republic of). Dept. of Agricultural Mechanization; Almassi, M.; Minaee, S. [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Dept. of Agricultural Mechanization; Widmann, R. [Duisburg-Essen Univ., Essen (Germany). Dept. of Environmental Engineering, Waste and Water

2010-07-01

This paper reported on a study in which hydrogen was produced by fermentation of biomass. A continuous process using a non-sterile substrate with a readily available mixed microflora was used on heat treated digested sewage sludge from a wastewater treatment plant. Hydrogen was produced from waste sugar at a pH of 5.2 and a temperature of 37 degrees C. An experimental setup of three 5.5 L working volume continuously stirred tank reactors (CSTR) in different stirring speeds were constructed and operated at 7 different hydraulic retention times (HRTs) and different organic loading rates (OLR). Dissolved organic carbon was examined. The results showed that the stirring speed of 135 rpm had a beneficial effect on hydrogen fermentation. The best performance was obtained in 135 rpm and 8 h of HRT. The amount of gas varied with different OLRs, but could be stabilized on a high level. Methane was not detected when the HRT was less than 16 h. The study identified the reactor in which the highest specific rate of hydrogen production occurred.

Application of starter cultures to table olive fermentation: an overview on the experimental studies

Directory of Open Access Journals (Sweden)

Aldo eCorsetti

2012-07-01

Full Text Available Table olives are one of the oldest fermented foods and they are considered an important component of the Mediterranean diet, since their richness in monounsaturated fats (primarily oleic acid and phenolic compounds that may function as antioxidants in the human body; in the Western world they represent one of the most popular fermented vegetables but, despite its economic significance, table olive fermentation is still craft-based and empirical. In particular, such a type of fermentation results from the competitive activities among indigenous, contaminating microorganisms, the microbial balance depending on several intrinsic (pH, water activity, diffusion of nutrients from the drupe and level of anti-microbial compounds and extrinsic (temperature, oxygen availability and salt concentration factors. At present, to reduce the risk of spoilage and to achieve a more predictable process there is an increasing interest in developing starter cultures for table olives fermentation. Anyway, the application of starter cultures in the field of table olives is quite far from reaching the diffusion it has in other sectors of food industry (e.g., dairy products and alcoholic beverages. This review focuses on experimental researches devoted to studying starter cultures for possible application to table olive fermentation both at artisan and industrial level.

Temperature control in a continuously mixed bioreactor for solid-state fermentation

NARCIS (Netherlands)

Nagel, F.J.J.I.; Tramper, J.; Bakker, M.S.N.; Rinzema, A.

2001-01-01

A continuously mixed, aseptic paddle mixer was used successfully for solid-state fermentation (SSF) with Aspergillus oryzae on whole wheat kernels. Continuous mixing improved temperature control and prevented inhomogeneities in the bed. Respiration rates found in this system were comparable to those

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

Science.gov (United States)

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.

Enhanced hydrogen and 1,3-propanediol production from glycerol by fermentation using mixed cultures

KAUST Repository

Selembo, Priscilla A.

2009-12-15

The conversion of glycerol into high value products, such as hydrogen gas and 1,3-propanediol (PD), was examined using anaerobic fermentation with heat-treated mixed cultures. Glycerol fermentation produced 0.28 mol-H 2/mol-glycerol (72 mL-H2/g-COD) and 0.69 mol-PD/mol-glycerol. Glucose fermentation using the same mixed cultures produced more hydrogen gas (1.06 mol-H2/mol-glucose) but no PD. Changing the source of inoculum affected gas production likely due to prior acclimation of bacteria to this type of substrate. Fermentation of the glycerol produced from biodiesel fuel production (70% glycerol content) produced 0.31 mol-H 2/mol-glycerol (43 mL H2/g-COD) and 0.59 mol-PD/mol-glycerol. These are the highest yields yet reported for both hydrogen and 1,3-propanediol production from pure glycerol and the glycerol byproduct from biodiesel fuel production by fermentation using mixed cultures. These results demonstrate that production of biodiesel can be combined with production of hydrogen and 1,3-propanediol for maximum utilization of resources and minimization of waste. © 2009 Wiley Periodicals, Inc.

Exploring the selective lactic acid production from food waste in uncontrolled pH mixed culture fermentations using different reactor configurations.

Science.gov (United States)

Bonk, Fabian; Bastidas-Oyanedel, Juan-Rodrigo; Yousef, Ahmed F; Schmidt, Jens Ejbye

2017-08-01

Carboxylic acid production from food waste by mixed culture fermentation is an important future waste management option. Obstacles for its implementation are the need of pH control, and a broad fermentation product spectrum leading to increased product separation costs. To overcome these obstacles, the selective production of lactic acid (LA) from model food waste by uncontrolled pH fermentation was tested using different reactor configurations. Batch experiments, semi-continuously fed reactors and a percolation system reached LA concentrations of 32, 16 and 15gCOD LA /L, respectively, with selectivities of 93%, 84% and 75% on COD base, respectively. The semi-continuous reactor was dominated by Lactobacillales. Our techno-economic analysis suggests that LA production from food waste can be economically feasible, with LA recovery and low yields remaining as major obstacles. To solve both problems, we successfully applied in-situ product extraction using activated carbon. Copyright © 2017 Elsevier Ltd. All rights reserved.

Control of Biogenic Amines in Fermented Sausages: Role of Starter Cultures

Science.gov (United States)

Latorre-Moratalla, M.L.; Bover-Cid, Sara; Veciana-Nogués, M.T.; Vidal-Carou, M.C.

2012-01-01

Biogenic amines show biological activity and exert undesirable physiological effects when absorbed at high concentrations. Biogenic amines are mainly formed by microbial decarboxylation of amino acids and thus are usually present in a wide range of foods, fermented sausages being one of the major biogenic amine sources. The use of selected starter cultures is one of the best technological measures to control aminogenesis during meat fermentation. Although with variable effectiveness, several works show the ability of some starters to render biogenic amine-free sausages. In this paper, the effect of different starter culture is reviewed and the factors determining their performance discussed. PMID:22586423

Control of biogenic amines in fermented sausages: role of starter cultures

Directory of Open Access Journals (Sweden)

Mariluz eLatorre-Moratalla

2012-05-01

Full Text Available Biogenic amines show biological activity and exert undesirable physiological effects when absorbed at high concentrations. Biogenic amines are mainly formed by microbial decarboxylation of amino acids and thus are usually present in a wide range of foods, fermented sausages being one of the major biogenic amine sources. The use of selected starter cultures is one of the best technological measures to control aminogenesis during meat fermentation. Although with variable effectiveness, several works show the ability of some starters to render biogenic amine-free sausages. In this paper, the effect of different starter culture is reviewed and the factors determining their performance discussed.

Modeling and Parameter Identification Involving 3-Hydroxypropionaldehyde Inhibitory Effects in Glycerol Continuous Fermentation

Directory of Open Access Journals (Sweden)

Zhaohua Gong

2012-01-01

Full Text Available Mathematical modeling and parameter estimation are critical steps in the optimization of biotechnological processes. In the 1,3-propanediol (1,3-PD production by glycerol fermentation process under anaerobic conditions, 3-hydroxypropionaldehyde (3-HPA accumulation would arouse an irreversible cessation of the fermentation process. Considering 3-HPA inhibitions to cells growth and to activities of enzymes, we propose a novel mathematical model to describe glycerol continuous cultures. Some properties of the above model are discussed. On the basis of the concentrations of extracellular substances, a parameter identification model is established to determine the kinetic parameters in the presented system. Through the penalty function technique combined with an extension of the state space method, an improved genetic algorithm is then constructed to solve the parameter identification model. An illustrative numerical example shows the appropriateness of the proposed model and the validity of optimization algorithm. Since it is difficult to measure the concentrations of intracellular substances, a quantitative robustness analysis method is given to infer whether the model is plausible for the intracellular substances. Numerical results show that the proposed model is of good robustness.

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

Science.gov (United States)

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

2015-03-02

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

Ethanol production in an integrated fermentation/membrane system. Process simulations and economics

Energy Technology Data Exchange (ETDEWEB)

Groot, W J; Kraayenbrink, M R; Lans, R.G.J.M. van der; Luyben, K C.A.M. [Delft Univ. of Technology (Netherlands). Dept. of Biochemical Engineering

1993-01-01

Four systems comprising of an ethanol fermentation integrated with microfiltration and/or pervaporation, and a conventional continuous culture, were compared with respect to the performance of the fermentation and economics. The processes are compared on the basis of the same kinetic model. It is found that cell retention by microfiltration leads to lower production costs, compared to a conventional continuous culture. Pervaporation becomes profitable at a high selectivity of ethanol/water separation and low membrane prices. (orig.).

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

Science.gov (United States)

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.

Cultivos de alta densidad celular por retención interna: aplicación a la fermentación continua de etanol High cell density cultures produced by internal retention: application in continuous ethanol fermentation

Directory of Open Access Journals (Sweden)

Godoy Rubén Darío

2004-12-01

Full Text Available El etanol ha generado gran interés por su potencial como combustible alternativo. No obstante, para que este producto sea competitivo económicamente, es necesario desarrollar procesos de fermentación que incrementen la baja productividad volumétrica lograda en cultivos convencionales (por lote o continuo, por medio de técnicas que permitan altas concentraciones celulares y reduzcan la inhibición por producto. Uno de los métodos empleados frecuentemente involucra la recirculación celular; por ello, en este trabajo se desarrolló un reactor de membrana incorporando un módulo de filtración, con unidades tubulares de 5 u,m en acero inoxidable, dentro de un fermentador de tanque agitado de 3L, para investigar su aplicación en la producción continua de etanol. Los efectos de la concentración celular y la caída de presión transmembranal sobre el flux de permeado fueron evaluados para probar el desempeño del módulo de filtración. Previa selección de las condiciones de fermentación (30 °C, 1,25 -1,75 vvm, pH 4,5, el sistema con retención celular interna fue operado en el cultivo continuo de Saccharomyces cerevisiae a partir de sacarosa. La permeabilidad de las unidades filtrantes fue mantenida mediante la aplicación de pulsos de aire. Más del 97% de las células cultivadas fueron retenidas en el fermentador, alcanzándose una concentración celular de 51 g/L y una productividad promedio de etanol, en el cultivo con retención celular, de 8,51 g/L.h, la cual fue dos veces mayor a la que se obtiene en un cultivo continuo convencional. Palabras clave: reactor de membrana, Saccharomyces cerevisiae, fermentación alcohólica, recirculación celular.Ethanol has provoked great interest due to its potential as an alternative fuel. Nevertheless, fermentation processes must be developed by increasing the low volumetric productivity achieved in conventional cultures (batch or continuous to make this product become economically competitive

Continuous alcoholic fermentation of blackstrap molasses

Energy Technology Data Exchange (ETDEWEB)

Borzani, W; Aquarone, E

1957-01-01

The sugar concentration and the fermentation-cycle time can be related by an equation, theoretically justified, if it is assumed that the sugar consumption has a reaction rate of -1. Agitation is probably the rate-determining factor for continous alcohol fermentation. Penicillin increases the efficiency by preventing contamination. After 30 hours of fermentation, the penicillin concentration was 25 to 60% of the initial antibiotic concentration. Laboratory and plant-scale fermentations with 1.0 unit/ml of penicillin were studied and found favorable. An increase in the alcohol yield (4.8 to 19.5%) and a reduction of the acid production (17.0 to 66.6%) were observed. Penicillin did not affect the final yeast count or the fermentation time, and Leuconostoc contamination was inhibited by 8.0 units/ml.

Ethanol production from biomass by repetitive solid-state fed-batch fermentation with continuous recovery of ethanol

Energy Technology Data Exchange (ETDEWEB)

Moukamnerd, Churairat; Kino-oka, Masahiro; Sugiyama, Minetaka; Kaneko, Yoshinobu; Harashima, Satoshi; Katakura, Yoshio [Osaka Univ. (Japan). Dept. of Biotechnology; Boonchird, Chuenchit [Mahidol Univ., Bangkok (Thailand). Dept. of Biotechnology; Noda, Hideo [Kansai Chemical Engineering Co., Ltd., Amagasaki (Japan); Ninomiya, Kazuaki [Kanazawa Univ. (Japan). Inst. of International Environment Technology; Shioya, Suteaki [Sojo Univ., Kumamoto (Japan). Dept. of Applied Life Science

2010-09-15

To save cost and input energy for bioethanol production, a consolidated continuous solid-state fermentation system composed of a rotating drum reactor, a humidifier, and a condenser was developed. Biomass, saccharifying enzymes, yeast, and a minimum amount of water are introduced into the system. Ethanol produced by simultaneous saccharification and fermentation is continuously recovered as vapor from the headspace of the reactor, while the humidifier compensates for the water loss. From raw corn starch as a biomass model, 95 {+-} 3, 226 {+-} 9, 458 {+-} 26, and 509 {+-} 64 g l{sup -1} of ethanol solutions were recovered continuously when the ethanol content in reactor was controlled at 10-20, 30-50, 50-70 and 75-85 g kg-mixture{sup -1}, respectively. The residue showed a lesser volume and higher solid content than that obtained by conventional liquid fermentation. The cost and energy for intensive waste water treatment are decreased, and the continuous fermentation enabled the sustainability of enzyme activity and yeast in the system. (orig.)

Optimization of Culture Medium for the Growth of Candida sp. and Blastobotrys sp. as Starter Culture in Fermentation of Cocoa Beans (Theobroma cacao) Using Response Surface Methodology (RSM).

Science.gov (United States)

Mahazar, N H; Zakuan, Z; Norhayati, H; MeorHussin, A S; Rukayadi, Y

2017-01-01

Inoculation of starter culture in cocoa bean fermentation produces consistent, predictable and high quality of fermented cocoa beans. It is important to produce healthy inoculum in cocoa bean fermentation for better fermented products. Inoculum could minimize the length of the lag phase in fermentation. The purpose of this study was to optimize the component of culture medium for the maximum cultivation of Candida sp. and Blastobotrys sp. Molasses and yeast extract were chosen as medium composition and Response Surface Methodology (RSM) was then employed to optimize the molasses and yeast extract. Maximum growth of Candida sp. (7.63 log CFU mL-1) and Blastobotrys sp. (8.30 log CFU mL-1) were obtained from the fermentation. Optimum culture media for the growth of Candida sp., consist of 10% (w/v) molasses and 2% (w/v) yeast extract, while for Blastobotrys sp., were 1.94% (w/v) molasses and 2% (w/v) yeast extract. This study shows that culture medium consists of molasses and yeast extract were able to produce maximum growth of Candida sp. and Blastobotrys sp., as a starter culture for cocoa bean fermentation.

Design of a lamella settler for biomass recycling in continuous ethanol fermentation process.

Science.gov (United States)

Tabera, J; Iznaola, M A

1989-04-20

The design and application of a settler to a continuous fermentation process with yeast recycle were studied. The compact lamella-type settler was chosen to avoid large volumes associated with conventional settling tanks. A rationale of the design method is covered. The sedimentation area was determined by classical batch settling rate tests and sedimentation capacity calculation. Limitations on the residence time of the microorganisms in the settler, rather than sludge thickening considerations, was the approach employed for volume calculation. Fermentation rate tests with yeast after different sedimentation periods were carried out to define a suitable residence time. Continuous cell recycle fermentation runs, performed with the old and new sedimentation devices, show that lamella settler improves biomass recycling efficiency, being the process able to operate at higher sugar concentrations and faster dilution rates.

Optimization of cyclosporin A production by Beauveria nivea in continuous fed-batch fermentation

Directory of Open Access Journals (Sweden)

Dong Huijun

2011-01-01

Full Text Available To develop the effective control method for fed-batch culture of cyclosporin A production, we chose fructose, L-valine and (NH42HPO4 as feeding nutrients and compared their productivities in relation to different concentrations. The feeding rate of three kinds of feeding materials was controlled to maintain the suitable residual concentration. The fed-batch fermentation results indicated that the optimal concentrations of fructose, L-valine and (NH42HPO4 were about 20 g/L, 0.5 g/L and 0.6 g/L for cyclosporin A production, respectively. The cultivation of Beauveria nivea could produce cyclosporin A up to 6.2 g/L for 240 hrs through a continuous feeding-rate-controlled-batch process under the optimal feeding conditions.

Boosting dark fermentation with co-cultures of extreme thermophiles for biohythane production from garden waste.

Science.gov (United States)

Abreu, Angela A; Tavares, Fábio; Alves, Maria Madalena; Pereira, Maria Alcina

2016-11-01

Proof of principle of biohythane and potential energy production from garden waste (GW) is demonstrated in this study in a two-step process coupling dark fermentation and anaerobic digestion. The synergistic effect of using co-cultures of extreme thermophiles to intensify biohydrogen dark fermentation is demonstrated using xylose, cellobiose and GW. Co-culture of Caldicellulosiruptor saccharolyticus and Thermotoga maritima showed higher hydrogen production yields from xylose (2.7±0.1molmol(-1) total sugar) and cellobiose (4.8±0.3molmol(-1) total sugar) compared to individual cultures. Co-culture of extreme thermophiles C. saccharolyticus and Caldicellulosiruptor bescii increased synergistically the hydrogen production yield from GW (98.3±6.9Lkg(-1) (VS)) compared to individual cultures and co-culture of T. maritima and C. saccharolyticus. The biochemical methane potential of the fermentation end-products was 322±10Lkg(-1) (CODt). Biohythane, a biogas enriched with 15% hydrogen could be obtained from GW, yielding a potential energy generation of 22.2MJkg(-1) (VS). Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhanced hydrogen and 1,3-propanediol production from glycerol by fermentation using mixed cultures

KAUST Repository

Selembo, Priscilla A.; Perez, Joe M.; Lloyd, Wallis A.; Logan, Bruce E.

2009-01-01

The conversion of glycerol into high value products, such as hydrogen gas and 1,3-propanediol (PD), was examined using anaerobic fermentation with heat-treated mixed cultures. Glycerol fermentation produced 0.28 mol-H 2/mol-glycerol (72 mL-H2/g

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

Science.gov (United States)

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.

Continuous cider fermentation with co-immobilized yeast and Leuconostoc oenos cells.

Science.gov (United States)

Nedovic; Durieuxb; Van Nedervelde L; Rosseels; Vandegans; Plaisant; Simon

2000-06-01

Ca-alginate matrix was used to co-immobilize Saccharomyces bayanus and Leuconostoc oenos in one integrated biocatalytic system in order to perform simultaneously alcoholic and malo-lactic fermentation of apple juice to produce cider, in a continuous packed bed bioreactor. The continuous process permitted much faster fermentation compared with the traditional batch process. The flavor formation was also better controlled. By adjusting the flow rate of feeding substrate through the bioreactor, i.e. its residence time, it was possible to obtain either "soft" or "dry" cider. However, the profile of volatile compounds in the final product was modified comparatively to the batch process, especially for higher alcohols, isoamylacetate, and diacetyl. This modification is due to different physiology states of yeast in two processes. Nevertheless, the taste of cider was quite acceptable.

Lactic acid bacteria as protective cultures in fermented pork meat to prevent Clostridium spp. growth.

Science.gov (United States)

Di Gioia, Diana; Mazzola, Giuseppe; Nikodinoska, Ivana; Aloisio, Irene; Langerholc, Tomaz; Rossi, Maddalena; Raimondi, Stefano; Melero, Beatriz; Rovira, Jordi

2016-10-17

In meat fermented foods, Clostridium spp. growth is kept under control by the addition of nitrite. The growing request of consumers for safer products has led to consider alternative bio-based approaches, the use of protective cultures being one of them. This work is aimed at checking the possibility of using two Lactobacillus spp. strains as protective cultures against Clostridium spp. in pork ground meat for fermented salami preparation. Both Lactobacillus strains displayed anti-clostridia activity in vitro using the spot agar test and after co-culturing them in liquid medium with each Clostridium strain. Only one of them, however, namely L. plantarum PCS20, was capable of effectively surviving in ground meat and of performing anti-microbial activity in carnis in a challenge test where meat was inoculated with the Clostridium strain. Therefore, this work pointed out that protective cultures can be a feasible approach for nitrite reduction in fermented meat products. Copyright © 2016 Elsevier B.V. All rights reserved.

Production of microbial biomass protein by sequential culture fermentation of Arachniotus sp., and Candida utilis

International Nuclear Information System (INIS)

Ahmed, S.; Ahmad, F.; Hashmi, A.S.

2010-01-01

Sequential culture fermentation by Arachniotus sp. at 35 deg. C for 72 h and followed by Candida utilis fermentation at 35 deg. C for 72 h more resulted in higher production of microbial biomass protein. 6% (w/v) corn stover, 0.0075% CaCl/sub 2/.2H/sub 2/O, 0.005% MgSO/sub 4/.7H/sub 2/O, 0.01% KH/sub 2/PO/sub 4/, C:N ratio of 30:1 and 1% molasses gave higher microbial biomass protein production by the sequential culture fermentation of Arachniotus sp., and C. utilis. The mixed microbial biomass protein produced in the 75-L fermentor contained 16.41%, 23.51%, 10.9%, 12.11% and 0.12% true protein, crude protein, crude fiber, ash and RNA content, respectively. The amino acid profile of final mixed microbial biomass protein showed that it was enriched with essential amino acids. Thus, the potential utilization of corn stover can minimize the cost for growth of these microorganisms and enhance microbial biomass protein production by sequential culture fermentation. (author)

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

Science.gov (United States)

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.

On-Line Optimizing Control of a Simulated Continuous Yeast Fermentation

DEFF Research Database (Denmark)

Andersen, Maria Y.; Asferg, L.; Brabrand, H.

1989-01-01

On-line optimizing control of a simulated fermentation is investigated using a non-segregated dynamic model of aerobic glucose limited growth of saccharomyces cerevisiae. The optimization procedure is carried out with an underlying adaptive regulator to stabilize the culture. This stabilization...... is especially important during the setpoint changes specified by the optimizing routine. A linear ARMAX model structure is used for the fermentation process with dilution rate as input and biomass as output variable. The parameters of the linear model structure are estimated using a pseudo linear regression...... method with bandpass filtering of in- and output variables in order to ensure low frequency validity of the estimated model. An LQ-regulator is used with iterative solution of the Riccati equation. Simulation results illustrate the tuning of the underlying regulator, and the effect of perturbing...

Modeling and Properties of Nonlinear Stochastic Dynamical System of Continuous Culture

Science.gov (United States)

Wang, Lei; Feng, Enmin; Ye, Jianxiong; Xiu, Zhilong

The stochastic counterpart to the deterministic description of continuous fermentation with ordinary differential equation is investigated in the process of glycerol bio-dissimilation to 1,3-propanediol by Klebsiella pneumoniae. We briefly discuss the continuous fermentation process driven by three-dimensional Brownian motion and Lipschitz coefficients, which is suitable for the factual fermentation. Subsequently, we study the existence and uniqueness of solutions for the stochastic system as well as the boundedness of the Two-order Moment and the Markov property of the solution. Finally stochastic simulation is carried out under the Stochastic Euler-Maruyama method.

Dynamics in population heterogeneity during batch and continuous fermentation of Saccharomyces cerevisiae

DEFF Research Database (Denmark)

Heins, Anna-Lena; Lencastre Fernandes, Rita; Lundin, L.

2012-01-01

Traditionally, microbial populations in optimization studies of fermentation processes have been considered homogeneous. However, research has shown that a typical microbial population in fermentation is heterogeneous. There are indications that this heterogeneity may be both beneficial...... (facilitates quick adaptation to new conditions) and harmful (reduces yields and productivities)[1,2]. Typically, gradients of e.g. dissolved oxygen, substrates, and pH are observed in industrial scale fermentation processes. Consequently, microbial cells circulating throughout a bioreactor experience rapid...... distribution during different growth stages. To further simulate which effect gradients have on population heterogeneity, glucose and ethanol perturbations during continuous cultivation were performed. Physiological changes were analyzed on single cell level by using flow cytometry followed by cell sorting...

Continuous production of lactic acid from molasses by perfusion culture of Lactococcus lactis using a stirred ceramic membrane reactor.

Science.gov (United States)

Ohashi, R; Yamamoto, T; Suzuki, T

1999-01-01

A perfusion culture system was used for continuous production of lactic acid by retaining cells at a high density of Lactococcus lactis in a stirred ceramic membrane reactor (SCMR). After the cell concentration increased to 248 g/l, half of the culture broth volume was replaced with the fermentation medium. Subsequently, a substrate solution containing glucose (run 1) or molasses (run 2) was continuously supplied to the cells retained in the SCMR. Simultaneously, the culture supernatant was extracted using a ceramic filter with a pore size of 0.2 mum. The dilution rate was initially set at 0.4 h(-1) and gradually decreased to 0.2 h(-1) due to reduction in the permeability of the filter. The concentration of glucose in the substrate solution was adjusted to 60 g/l for the transition and the first period until 240 h, 90 g/l for the second period from 240 h to 440 h, and 70 g/l for the third period from 440 h to 643 h. The average concentration of lactic acid in the filtrate reached 46 g/l in the first period, 43 g/l in the second period, and 33 g/l for the third period. The productivity obtained for the first period reached 15.8 g.l(-1).h(-1), twice as much as that achieved in repeated batch fermentations. Based on the results obtained in run 1, the substrate solution containing 120 g/l of molasses was continuously supplied for 240 h in run 2. The concentration and productivity of lactic acid reached 40 g/l and 10.6 g.l(-1).h(-1), respectively, by continuously replenishing the culture medium at a dilution rate of 0.26 h(-1). These results demonstrated that the filtration capacity of the SCMR was sufficient for a continuous and rapid replenishment of molasses solution from the dense cell culture and, therefore, the perfusion culture system is considered to provide a low-cost process for continuous production of lactic acid from cheap resources.

Fermentative capabilities and volatile compounds produced by Kloeckera/Hanseniaspora and Saccharomyces yeast strains in pure and mixed cultures during Agave tequilana juice fermentation.

Science.gov (United States)

González-Robles, Ivonne Wendolyne; Estarrón-Espinosa, Mirna; Díaz-Montaño, Dulce María

2015-09-01

The fermentative and aromatic capabilities of Kloeckera africana/Hanseniaspora vineae K1, K. apiculata/H. uvarum K2, and Saccharomyces cerevisiae S1 and S2 were studied in pure and mixed culture fermentations using Agave tequila juice as the culture medium. In pure and mixed cultures, Kloeckera/Hanseniaspora strains showed limited growth and sugar consumption, as well as low ethanol yield and productivity, compared to S. cerevisiae, which yielded more biomass, ethanol and viable cell concentrations. In pure and mixed cultures, S. cerevisiae presented a similar behaviour reaching high biomass production, completely consuming the sugar, leading to high ethanol production. Furthermore, the presence of S. cerevisiae strains in the mixed cultures promoted the production of higher alcohols, acetaldehyde and ethyl esters, whereas Kloeckera/Hanseniaspora strains stimulated the production of ethyl acetate and 2-phenyl ethyl acetate compounds.

The cocoa bean fermentation process: from ecosystem analysis to starter culture development.

Science.gov (United States)

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.

Effect of cultural conditions on antrodin C production by basidiomycete Antrodia camphorata in solid-state fermentation.

Science.gov (United States)

Xia, Yongjun; Wang, Yuanlong; Zhang, Bobo; Xu, Ganrong; Ai, Lianzhong

2014-01-01

Antrodia camphorata is a medicinal fungus and antrodin C is one of the main bioactive components of A. camphorata in the submerged fermentation (SmF). To optimize the culture conditions, the factors influencing the production of antrodin C by A. camphorata under solid-state fermentation (SSF) were investigated in this study. Different solid substrates and external nitrogen sources were tested for their efficiency in producing antrodin C. The response surface methodology was applied to evaluate the influence of several variables, namely, the concentrations of soybean meal, initial moisture content, and inoculum density on antrodin C production in solid-state fermentation. The experimental results show that the optimum fermentation medium for antrodin C production by A. camphorata was composed of 0.578 g soybean meal, 0.05 g Na2 HPO4 , 0.05 g MgSO4 for 100 g rice, with 51.83% initial moisture content, 22 day culture time, 28 °C culture temperature, and 35.54% inoculum density. At optimized conditions, 6,617.36 ± 92.71 mg kg(-1) yield of antrodin C was achieved. Solid-state fermentation is one good cultural method to improve the production of antrodin C by A. camphorata. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

Effect of aeration on the fermentative activity of Saccharomyces cerevisiae cultured in apple juice

OpenAIRE

Estela-Escalante, W.; Rychtera, M.; Melzoch, K.; Hatta-Sakoda, B.

2012-01-01

The influence of aeration on the fermentative activity of Saccharomyces cerevisiaeRTVE V 15-1-416 was studied in order to evaluate the synthesis of fermentation by-products. To achieve this, the strain was cultured in Erlenmeyer flasks and bioreactor containing sterilized and aroma removed apple juice. The chemical compounds produced during fermentations in shaken (200 min-¹) and static (without agitation) flasks and bioreactor, all in batch mode, were determined by GC and HPLC. The results s...

Starter Culture Selection for Making Chinese Sesame-Flavored Liquor Based on Microbial Metabolic Activity in Mixed-Culture Fermentation

Science.gov (United States)

Wu, Qun; Ling, Jie

2014-01-01

Selection of a starter culture with excellent viability and metabolic activity is important for inoculated fermentation of traditional food. To obtain a suitable starter culture for making Chinese sesame-flavored liquor, the yeast and bacterium community structures were investigated during spontaneous and solid-state fermentations of this type of liquor. Five dominant species in spontaneous fermentation were identified: Saccharomyces cerevisiae, Pichia membranaefaciens, Issatchenkia orientalis, Bacillus licheniformis, and Bacillus amyloliquefaciens. The metabolic activity of each species in mixed and inoculated fermentations of liquor was investigated in 14 different cocultures that used different combinations of these species. The relationships between the microbial species and volatile metabolites were analyzed by partial least-squares (PLS) regression analysis. We found that S. cerevisiae was positively correlated to nonanal, and B. licheniformis was positively associated with 2,3-butanediol, isobutyric acid, guaiacol, and 4-vinyl guaiacol, while I. orientalis was positively correlated to butyric acid, isovaleric acid, hexanoic acid, and 2,3-butanediol. These three species are excellent flavor producers for Chinese liquor. Although P. membranaefaciens and B. amyloliquefaciens were not efficient flavor producers, the addition of them alleviated competition among the other three species and altered their growth rates and flavor production. As a result, the coculture of all five dominant species produced the largest amount of flavor compounds. The result indicates that flavor producers and microbial interaction regulators are important for inoculated fermentation of Chinese sesame-flavored liquor. PMID:24814798

Continuous dry fermentation of swine manure for biogas production

Energy Technology Data Exchange (ETDEWEB)

Chen, Chuang; Zheng, Dan [Biogas Institute of Ministry of Agriculture, Chengdu 610041 (China); Liu, Gang–Jin [Biogas Institute of Ministry of Agriculture, Chengdu 610041 (China); Bioprocess Control AB, Scheelevägen 22, 223 63 Lund (Sweden); Deng, Liang–Wei, E-mail: dengliangwei@caas.cn [Biogas Institute of Ministry of Agriculture, Chengdu 610041 (China); Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture, Chengdu 610041 (China); Southwest Collaborative Innovation Center of Swine for Quality & Safety, Chengdu 611130 (China); Long, Yan; Fan, Zhan–Hui [Biogas Institute of Ministry of Agriculture, Chengdu 610041 (China)

2015-04-15

Highlights: • Continuous dry fermentation of swine manure for biogas production is feasible. • The feedstock TS concentration exerted a significant impact on biogas production. • Influences of ammonia and digestate liquidity were investigated in this study. • The results showed that the feedstock TS of swine manure should not exceed 30%. - Abstract: A down plug-flow anaerobic reactor (DPAR) was designed for the feasibility study on continuous dry fermentation of swine manure without any additional stirring. Using fresh swine manure as the feedstock with TS concentration (w/w) of 20%, 25%, 30%, and 35%, stable volumetric biogas production rates of 2.40, 1.92, 0.911, and 0.644 L·(L d){sup −1} and biogas yields of 0.665, 0.532, 0.252, and 0.178 L g{sup −1}VS were obtained respectively, and the TS degradation rates were 46.5%, 45.4%, 53.2%, and 55.6%, respectively. With the increase of feedstock TS concentration, the concentration of ammonia nitrogen grew up to the maximum value of 3500 mg L{sup −1}. Biogas production was obviously inhibited when the concentration of ammonia nitrogen was above 3000 mg L{sup −1}. The maximal volumetric biogas production rate of 2.34 L·(L d){sup −1} and biogas yield of 0.649 L g{sup −1}VS were obtained with TS concentration of 25% at 25 °C without inhibition. Liquidity experiments showed that TS concentration of digestate could be less than 15.8%, and the flow rate of digestate more than 0.98 m s{sup −1} when the feedstock TS concentration was less than 35%, which indicated the digestate could be easily discharged from a DPAR. Therefore, it is feasible to conduct a continuous dry fermentation in a DPAR using fresh swine manure as the feedstock with TS concentration less than 35%, whereas the feedstock TS concentration should not exceed 30% to achieve the maximal biogas production rate and biogas yield.

Continuous dry fermentation of swine manure for biogas production

International Nuclear Information System (INIS)

Chen, Chuang; Zheng, Dan; Liu, Gang–Jin; Deng, Liang–Wei; Long, Yan; Fan, Zhan–Hui

2015-01-01

Highlights: • Continuous dry fermentation of swine manure for biogas production is feasible. • The feedstock TS concentration exerted a significant impact on biogas production. • Influences of ammonia and digestate liquidity were investigated in this study. • The results showed that the feedstock TS of swine manure should not exceed 30%. - Abstract: A down plug-flow anaerobic reactor (DPAR) was designed for the feasibility study on continuous dry fermentation of swine manure without any additional stirring. Using fresh swine manure as the feedstock with TS concentration (w/w) of 20%, 25%, 30%, and 35%, stable volumetric biogas production rates of 2.40, 1.92, 0.911, and 0.644 L·(L d) −1 and biogas yields of 0.665, 0.532, 0.252, and 0.178 L g −1 VS were obtained respectively, and the TS degradation rates were 46.5%, 45.4%, 53.2%, and 55.6%, respectively. With the increase of feedstock TS concentration, the concentration of ammonia nitrogen grew up to the maximum value of 3500 mg L −1 . Biogas production was obviously inhibited when the concentration of ammonia nitrogen was above 3000 mg L −1 . The maximal volumetric biogas production rate of 2.34 L·(L d) −1 and biogas yield of 0.649 L g −1 VS were obtained with TS concentration of 25% at 25 °C without inhibition. Liquidity experiments showed that TS concentration of digestate could be less than 15.8%, and the flow rate of digestate more than 0.98 m s −1 when the feedstock TS concentration was less than 35%, which indicated the digestate could be easily discharged from a DPAR. Therefore, it is feasible to conduct a continuous dry fermentation in a DPAR using fresh swine manure as the feedstock with TS concentration less than 35%, whereas the feedstock TS concentration should not exceed 30% to achieve the maximal biogas production rate and biogas yield

Analysis of continuous fermentation processes in aqueous two-phase systems

Energy Technology Data Exchange (ETDEWEB)

Jarzebski, A B; Malinowski, J J [Polish Academy of Sciences, Gliwice (Poland). Inst. of Chemical Engineering; Goma, G; Soucaille, P [INSA, 31 - Toulouse (France). Dept. de Genie Biochimique et Alimentaire

1992-05-01

Simulations of continuous ethanol or acetonobutylic fermentations in aqueous two-phase systems show that at high substrate feed concentrations it is possible to obtain solvent productivities about 25-40% higher than in conventional systems with cell recycle if the biomass bleed rate is kept about one tenth of the value of D. (orig.).

Characteristic of fermented spinach (Amaranthus spp.) polyphenol by kombucha culture for antioxidant compound

Science.gov (United States)

Aspiyanto, Susilowati, Agustine; Iskandar, Jeti M.; Melanie, Hakiki; Maryati, Yati; Lotulung, Puspa D.

2017-01-01

Fermentation on spinach (Amaranthus sp.) vegetable by kombucha culture as an effort to get poliphenol as antioxidant compound had been done. Purification of fermented spinach extract suspension was carried out through microfiltration (MF) membrane (pore size 0.15 µm) fitted in dead-end Stirred Ultrafiltration Cell (SUFC) mode at fixed condition (stirrer rotation 400 rpm, room temperature, pressure 40 psia). Result of the experimental activity showed that long fermentation time increased total acids, total polyphenol and Total Plate Count (TPC), and decreased total solids and reducing sugar in biomass. The optimal fermentation time was reached for 2 weeks with total polyphenol recovery increasing of 92.76 % from before and after fermentation. On this optimal fermentation time, biomass had identified galic acid with relative intensity of 8 %, while as polyphenol monomer was resulted 5 kinds of polyphenol compounds with total intensity 27.97 % and molecular weight (MW) 191.1736, 193.1871 and 194.2170 at T2.5, T2.86 and T3.86. Long fermentation time increased functional properties of polyphenol as antioxidant.

A meta-analysis of variability in continuous-culture ruminal fermentation and digestibility data.

Science.gov (United States)

Hristov, A N; Lee, C; Hristova, R; Huhtanen, P; Firkins, J L

2012-09-01

A meta-analysis was conducted to compare ruminal fermentation and digestibility data and variability between continuous-culture (CC) experiments and in vivo data. One hundred eighty CC studies representing 1,074 individual treatments, published in refereed journals between 1980 and 2010 were used in this analysis. Studies were classified into 2 groups based on the type of CC used: CC systems specified as rumen simulation techniques (RUSITEC) and non-RUSITEC CC systems (non-RUSITEC). The latter was a diverse group of systems, all of which were termed CC by the investigators. The CC data were compared with a data set of in vivo trials with ruminally cannulated lactating dairy cows (data from a total of 366 individual cows). The reported neutral detergent fiber (NDF) concentration of the diets fed in the 3 data sets was, on average (dry matter basis), 44, 34, and 32%, respectively. The average total volatile fatty acid (VFA) concentration for the RUSITEC and non-RUSITEC data sets was 67 and 80% (respectively) of the total VFA concentration in vivo. The average concentration of acetate was also lower for the CC data sets compared with in vivo and that of propionate was considerably lower for RUSITEC compared with in vivo, but butyrate concentrations were similar between the CC and in vivo data sets. Variability in the VFA data was generally the highest (higher coefficients of variation and variance) for the non-RUSITEC data set, followed by RUSITEC, and was the lowest for in vivo. Digestibilities of NDF and particularly organic matter were lower in the CC data sets compared with in vivo; the average NDF digestibility was 34.2, 45.5, and 53.0% for RUSITEC, non-RUSITEC, and in vivo, respectively. Variability in nutrient digestibility data followed the pattern of variability of the VFA data: highest variability for the non-RUSITEC data set, followed by RUSITEC, and the lowest for in vivo. This analysis showed that CC systems are generally characterized by lower total VFA

Gradient simulation experiments for targeting population heterogeneity in continuous Saccharomyces cerevisiae fermentation

DEFF Research Database (Denmark)

Heins, Anna-Lena; Lencastre Fernandes, Rita; Lundin, L.

Traditionally, a microbial population has been considered homogeneous in optimization studies of fermentation processes. However, research has shown that a typical microbial population in a fermenter is heterogeneous. There are indications that such heterogeneity may be both beneficial (facilitates...... quick adaptation to new conditions) and harmful (reduces yields and productivities) (Bylund et al. (1998); Enfors et al. (2001)). Significant gradients of e.g. dissolved oxygen, substrates, and pH are typically observed in many industrial scale fermentation processes. Consequently, the microbial cells...... reporter strain demonstrated a highly dynamic behaviour with regards to subpopulation distribution during the different growth stages. To simulate which effect glucose gradients, often seen in large scale cultivations, have on population heterogeneity, glucose perturbations during continuous cultivation...

Comparative analysis of microbial community of novel lactic acid fermentation inoculated with different undefined mixed cultures.

Science.gov (United States)

Liang, Shaobo; Gliniewicz, Karol; Mendes-Soares, Helena; Settles, Matthew L; Forney, Larry J; Coats, Erik R; McDonald, Armando G

2015-03-01

Three undefined mixed cultures (activated sludge) from different municipal wastewater treatment plants were used as seeds in a novel lactic acid fermentation process fed with potato peel waste (PPW). Anaerobic sequencing batch fermenters were run under identical conditions to produce predominantly lactic acid. Illumina sequencing was used to examine the 16S rRNA genes of bacteria in the three seeds and fermenters. Results showed that the structure of microbial communities of three seeds were different. All three fermentation products had unique community structures that were dominated (>96%) by species of the genus Lactobacillus, while members of this genus constituted undefined mixed cultures were robust and resilient, which provided engineering prospects for the microbial utilization of carbohydrate wastes to produce lactic acid. Copyright © 2014 Elsevier Ltd. All rights reserved.

Lactic acid production from submerged fermentation of broken rice using undefined mixed culture.

Science.gov (United States)

Nunes, Luiza Varela; de Barros Correa, Fabiane Fernanda; de Oliva Neto, Pedro; Mayer, Cassia Roberta Malacrida; Escaramboni, Bruna; Campioni, Tania Sila; de Barros, Natan Roberto; Herculano, Rondinelli Donizetti; Fernández Núñez, Eutimio Gustavo

2017-04-01

The present work aimed to characterize and optimize the submerged fermentation of broken rice for lactic acid (LA) production using undefined mixed culture from dewatered activated sludge. A microorganism with amylolytic activity, which also produces LA, Lactobacillus amylovorus, was used as a control to assess the extent of mixed culture on LA yield. Three level full factorial designs were performed to optimize and define the influence of fermentation temperature (20-50 °C), gelatinization time (30-60 min) and broken rice concentration in culture medium (40-80 g L -1 ) on LA production in pure and undefined mixed culture. LA production in mixed culture (9.76 g L -1 ) increased in sixfold respect to pure culture in optimal assessed experimental conditions. The optimal conditions for maximizing LA yield in mixed culture bioprocess were 31 °C temperature, 45 min gelatinization time and 79 g L -1 broken rice concentration in culture medium. This study demonstrated the positive effect of undefined mixed culture from dewatered activated sludge to produce LA from culture medium formulated with broken rice. In addition, this work establishes the basis for an efficient and low-cost bioprocess to manufacture LA from this booming agro-industrial by-product.

Direct Succinic Acid Production from Minimally Pretreated Biomass Using Sequential Solid-State and Slurry Fermentation with Mixed Fungal Cultures

Directory of Open Access Journals (Sweden)

Jerico Alcantara

2017-06-01

Full Text Available Conventional bio-based succinic acid production involves anaerobic bacterial fermentation of pure sugars. This study explored a new route for directly producing succinic acid from minimally-pretreated lignocellulosic biomass via a consolidated bioprocessing technology employing a mixed lignocellulolytic and acidogenic fungal co-culture. The process involved a solid-state pre-fermentation stage followed by a two-phase slurry fermentation stage. During the solid-state pre-fermentation stage, Aspergillus niger and Trichoderma reesei were co-cultured in a nitrogen-rich substrate (e.g., soybean hull to induce cellulolytic enzyme activity. The ligninolytic fungus Phanerochaete chrysosporium was grown separately on carbon-rich birch wood chips to induce ligninolytic enzymes, rendering the biomass more susceptible to cellulase attack. The solid-state pre-cultures were then combined in a slurry fermentation culture to achieve simultaneous enzymatic cellulolysis and succinic acid production. This approach generated succinic acid at maximum titers of 32.43 g/L after 72 h of batch slurry fermentation (~10 g/L production, and 61.12 g/L after 36 h of addition of fresh birch wood chips at the onset of the slurry fermentation stage (~26 g/L production. Based on this result, this approach is a promising alternative to current bacterial succinic acid production due to its minimal substrate pretreatment requirements, which could reduce production costs.

Biomass production of pleurotus sajor-caju by submerged culture fermentation

International Nuclear Information System (INIS)

Kausar, T.; Nasreen, Z.; Nadeem, M.; Baig, S.

2006-01-01

The effect of different carbon sources, namely, sawdust and powder of agro wastes (as such, or water soluble extracts), and inorganic/natural nitrogen sources on the biomass production of Pleurotus sajor-caju by submerged culture fermentation was studied. Supplementation of the fermentation medium with 2% molasses, 2% wheat spike powder, extract of 2% wheat spike powder, and com gluten meal resulted in 12.85, 10.85, 12.35 and 13.92 g/sub l/ biomass production of P. sajor-caju, respectively. The fungal hyphae biomass contained 8.28% moisture, 21.18% crude protein, 1.55% fat, 3.59% ash, 2.32% crude fibre, and 63.48% nitrogen-free extract. (author)

Optimization of asparaginase production from Zymomonas mobilis by continuous fermentation

Directory of Open Access Journals (Sweden)

Francieli Bortoluzzi Menegat

2016-10-01

Full Text Available Asparaginase is an enzyme used in clinical treatments as a chemotherapeutic agent and in food technology to prevent acrylamide formation in fried and baked foods. Asparaginase is industrially produced by microorganisms, mainly gram-negative bacteria. Zymomonas mobilis is a Gram-negative bacterium that utilizes glucose, fructose and sucrose as carbon source and has been known for its efficiency in producing ethanol, sorbitol, levan, gluconic acid and has recently aroused interest for asparaginase production. Current assay optimizes the production of Z. mobilis asparaginase by continuous fermentation using response surface experimental design and methodology. The studied variables comprised sucrose, yeast extract and asparagine. Optimized condition obtained 117.45 IU L-1 with dilution rate 0.20 h-1, yeast extract 0.5 g L-1, sucrose 20 g L-1 and asparagine 1.3 g L-1. Moreover, carbon:nitrogen ratio (1:0.025 strongly affected the response of asparaginase activity. The use of Z. mobilis by continuous fermentation has proved to be a promising alternative for the biotechnological production of asparaginase.

Aminogenesis control in fermented sausages manufactured with pressurized meat batter and starter culture.

Science.gov (United States)

Latorre-Moratalla, M L; Bover-Cid, S; Aymerich, T; Marcos, B; Vidal-Carou, M C; Garriga, M

2007-03-01

The application of high hydrostatic pressure (200MPa) to meat batter just before sausage fermentation and the inoculation of starter culture were studied to improve the safety and quality of traditional Spanish fermented sausages (fuet and chorizo). Higher amounts of biogenic amines were formed in chorizo than in fuet. Without interfering with the ripening performance in terms of acidification, drying and proteolysis, hydrostatic pressure prevented enterobacteria growth but did not affect Gram-positive bacteria significantly. Subsequently, a strong inhibition of diamine (putrescine and cadaverine) accumulation was observed, but that of tyramine was not affected. The inoculated decarboxylase-negative strains, selected from indigenous bacteria of traditional sausages, were resistant to the HHP treatment, being able to lead the fermentation process, prevent enterococci development and significantly reduce enterobacteria counts. In sausages manufactured with either non-pressurized or pressurized meat batter, starter culture was the most protective measure against the accumulation of tyramine and both diamines.

Process of preparing ethanol by continuous fermentation of polysaccharide-containing materials

Energy Technology Data Exchange (ETDEWEB)

Ehnstroem, L.K.J.

1981-04-16

The invention concerns a process of preparing ethanol by continuous fermentation of polysaccharide - containing raw materials. Fermentation, hereby, occurs in one or several fermentors while dividing one stream of the fermentation liquid into a yeast-concentrate stream and a yeast-free stream and, if neccessary, a sludge stream. The yeast-concentrate stream is re-fed into the fermentor and at least part of the yeast-free stream is directed into a simple evaporator corresponding to one or several distilling stages where it is separated partially in an ethanol-enriched initial vapour stream supplying a facility to produce the desired ethanol quality, and partially in a liquid initial bottom stream re-fed at least in part into the fermentor. The characteristic feature of this new process is that a raw-material stream is fed into a closed circuit containing the fermentor and the evaporator, and that, in the evaporator, the raw-material stream is hydrolysed to a fermentable state. This hydrolysis is carried out most favourably by enzymes - preferably a gluco-amylase - at a temperature ranging from 35/sup 0/C to 75/sup 0/C.

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

OpenAIRE

Karslo?lu, Bet?l; ?i?ek, ?mran Ensoy; Kolsarici, Nuray; Cando?an, 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

Comparative study of physicochemical analysis of prosopis africana seeds fermented with different starter cultures

Directory of Open Access Journals (Sweden)

G. P. Oyeyiola

2017-01-01

Full Text Available Prosopis africana (African mesquite is one of the lesser known legume seed crops in Nigeria, which in a fermented state, gives a food condiment. Because of its rich protein content (about 34%, efforts are made to utilize some lesser known legumes to improve the nutritional status of the people. This study was carried out by fermenting Prosopis africana seeds with mono and mixed cultures of bacterial isolates to produce a local condiment called Okpehe. Standard AOAC methods were used to determine the pH, total sugar and crude protein content of the fermented seeds. During the production of Okpehe with mono cultures of bacteria, the pH ranged between 6.80 and 8.92; total sugar between 10.2 and 7.5 mg/g, and crude protein between 34.62 and 41.25%. In the mixed culture inoculated samples, the pH increased from 7.00 to 8.92; total sugar decreased from 9.4 to 7.4 mg/g, while the crude protein increased (35.02 - 44.61% significantly (p < 0.05 as the fermentation progressed. The highest crude protein content of 44.61% was obtained with the combination of Bacillus subtilis and Bacillus licheniformis, while the lowest protein content referred to the combination of Bacillus megaterium and Bacillus pumilus. The result of this study showed that Prosopis africana seeds could be utilized for the production of Okpehe using mixed cultures of B. subtilis and B. licheniformis, so as to increase the protein intake of the populace.

A novel approach of modeling continuous dark hydrogen fermentation.

Science.gov (United States)

Alexandropoulou, Maria; Antonopoulou, Georgia; Lyberatos, Gerasimos

2018-02-01

In this study a novel modeling approach for describing fermentative hydrogen production in a continuous stirred tank reactor (CSTR) was developed, using the Aquasim modeling platform. This model accounts for the key metabolic reactions taking place in a fermentative hydrogen producing reactor, using fixed stoichiometry but different reaction rates. Biomass yields are determined based on bioenergetics. The model is capable of describing very well the variation in the distribution of metabolic products for a wide range of hydraulic retention times (HRT). The modeling approach is demonstrated using the experimental data obtained from a CSTR, fed with food industry waste (FIW), operating at different HRTs. The kinetic parameters were estimated through fitting to the experimental results. Hydrogen and total biogas production rates were predicted very well by the model, validating the basic assumptions regarding the implicated stoichiometric biochemical reactions and their kinetic rates. Copyright © 2017 Elsevier Ltd. All rights reserved.

Electrochemically Driven Fermentation of Organic Substrates with Undefined Mixed Microbial Cultures.

Science.gov (United States)

Villano, Marianna; Paiano, Paola; Palma, Enza; Miccheli, Alfredo; Majone, Mauro

2017-08-10

Growing scientific interest in mixed microbial culture-based anaerobic biotechnologies for the production of value-added chemicals and fuels from organic waste residues requires a parallel focus on the development and implementation of strategies to control the distribution of products. This study examined the feasibility of an electrofermentation approach, based on the introduction of a polarized (-700 mV vs. the standard hydrogen electrode) graphite electrode in the fermentation medium, to steer the product distribution during the conversion of organic substrates (glucose, ethanol, and acetate supplied as single compounds or in mixtures) by undefined mixed microbial cultures. In batch experiments, the polarized electrode triggered a nearly 20-fold increase (relative to open circuit controls) in the yield of isobutyrate production (0.43±0.01 vs. 0.02±0.02 mol mol -1 glucose) during the anaerobic fermentation of the ternary mixture of substrates, without adversely affecting the rate of substrate bioconversion. The observed change in the fermentative metabolism was most likely triggered by the (potentiostatic) regulation of the oxidation-reduction potential of the reaction medium rather than by the electrode serving as an electron donor. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Continuous fermentation of whey into alcohol using an attached film expanded bed reactor

Energy Technology Data Exchange (ETDEWEB)

Chen, H C; Zall, R R

1982-01-01

Batch and continuous processes were studied using a lactose- fermenting yeast, Saccharomyces fragi. Batch methods were used to study the effects of temperature, pH, yeast extract, and ergosterol on ethanol and cell mass production. The optimal temperature ranged from 32 to 37 degrees C. No pH control appeared necessary for whey fermentation. Supplements of yeast extract and ergosterol appeared to have pronounced effect on cell mass and ethanol production. Overall, whey reconstituted from acid whey powder containing 10% lactose could be converted to 36.5 g/l of ethanol in 44 hours when the material was supplemented with 0.7% yeast extract, 10 mg/l ergosterol, and fermented at 32 degrees C using 2.67% aerobically grown inoculum containing approximately 110 x 10 to the power of 6 CFU/ml. Ethanol productivity as high as 6.9 g/lj/h was achieved in a continuous attached film expanded bed fermentor using cellulose acetate as support media. The retention time was 1.1 hour and effluent ethanol concentration was 7.6 g/l. (Refs. 27).

Continuous high-solids corn liquefaction and fermentation with stripping of ethanol.

Science.gov (United States)

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.

Continuous determination of volatile products in anaerobic fermenters by on-line capillary gas chromatography

International Nuclear Information System (INIS)

Diamantis, V.; Melidis, P.; Aivasidis, A.

2006-01-01

Bio-ethanol and biogas produced during the anaerobic conversion of organic compounds has been a subject of great interest since the oil crisis of the 1970s. In ethanol fermentation and anaerobic treatment of wastewaters, end-product (ethanol) and intermediate-products (short-chain fatty acids, SCFA) cause inhibition that results in reduced process efficiency. Control of these constituents is of utmost importance for bioreactor optimization and process stability. Ethanol and SCFA can be detected with precision by capillary gas chromatography usually conducted in off-line measurements. In this work, an on-line monitoring and controlling system was developed and connected to the fermenter via an auto-sampling equipment, which could perform the feeding, filtration and dilution of the sample and final injection into the gas chromatograph through an automation-based programmed procedure. The sample was continuously pumped from the recycle stream of the bioreactor and treated using a microfiltration unit. The concentrate was returned to the reactor while the permeate was quantitatively mixed with an internal standard solution. The system comprised of a gas chromatograph with the flow cell and one-shot sampler and a PC with the appropriate software. The on-line measurement of ethanol and SCFA, directly from the liquid phase of an ethanol fermenter and a high-rate continuous mode anaerobic digester, was accomplished by gas chromatography. Also, this monitoring and controlling system was proved to be effective in the continuous fermentation of alcohol-free beer

Sequential culture with Torulaspora delbrueckii and Saccharomyces cerevisiae and management of fermentation temperature to improve cherry wine quality.

Science.gov (United States)

Sun, Shu Yang; Gong, Han Sheng; Zhao, Yu Ping; Liu, Wen Li; Jin, Cheng Wu

2016-04-01

There has been limited research on the use of non-Saccharomyces yeasts for the production of cherry wines. This work used an autochthonous Torulaspora delbrueckii strain 49 (TD49) in association with a commercial S. cerevisiae RC212 yeast, to investigate the effect of multi-starter culture (sequential inoculation and simultaneous inoculation) and fermentation temperature on the quality of cherry wines. Both TD49 and RC212 proliferated during alcoholic fermentation (AF) under sequential inoculation conditions, whereas in the case of simultaneous inoculation, TD49 increased slowly at first and then declined sharply near the fermentation end. The analytical profile showed that both mixed fermentations produced lower levels of volatile acidy and higher levels of aromatic compounds than those from RC212 mono-culture. During sensory analysis, wines from sequential fermentation obtained the highest score, mainly due to the higher intensity in 'fruity' and 'floral' characters. As for the influence of temperature, a low temperature (20 °C) enhanced TD49 persistence during AF, but the sensory quality decreased anyway; 30 °C resulted in decreases in most measured descriptors. Therefore, 25 °C was selected as the best culture temperature. TD49/RC212 sequential inoculation and fermentation at 25 °C significantly enhanced the cherry wine quality. © 2015 Society of Chemical Industry.

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

Science.gov (United States)

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

2018-03-24

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.

Antioxidant activity of fermented broccoli and spinach by Kombucha culture

Science.gov (United States)

Artanti, Nina; Susilowati, Agustine; Aspiyanto, Lotulung, Puspa Dewi Narrij; Maryati, Yati

2017-11-01

Broccoli (Brassica oleracea L.) and spinach (Amaranthus spp.) are vegetables that known to have many benefit for health. Previous studies on the fermentation of those vegetables using kombucha cultured showed increase in bioactive components such as total polyphenol content. The current studies was performed to evaluate the antioxidant activity of fermented spinach and broccoli before (feed) and after treatment with filtration (retentate and permeate). Filtration was conducted using Stirred Ultrafiltration Cell (SUFC) with UF membrane 100,000 MWCO mode at fixed condition (stirred rotation 300 rpm, room temperature, pressure 40 psia). Antioxidant evaluation was conducted using 2,2-diphenyl-1-picril hydrazyl (DPPH) free radical scavenging activity assay. The results showed that all samples from fermented broccoli showed antioxidant activity (feed 15.82% inhibition and retentate 15.29% inhibition), with the best antioxidant activity was obtained from permeate (75.98% inhibition). Whereas from fermented spinach only permeate showed antioxidant activity (21.84% inhibition) and it significantly lower than broccoli permeate. The mass spectrum of LCMS analysis on broccoli samples showed the present of several mass spectrum with (M+H) range from 148.1 to 442.5 in feed, retentate and permeate. In those samples (M+H) 360.4 always has the highest relative intensity. These results suggest that fermented broccoli has potential for development as functional drink for the source of antioxidant and the permeate obtained from filtration treatment significantly increased the antioxidant activity.

Effect of starter cultures combinations on lipolytic activity and ripening of dry fermented sausages

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Enver Baris Bingol

2014-11-01

Full Text Available The effect of starter culture combinations on the quality of Turkish type dry fermented sausage (sucuk were evaluated during ripening and storage periods. Sucuk formulations were produced without (control and with three different starter culture combinations; i Staphylococcus carnosus+Pediococcus pentosaceus, ii Staphylococcus carnosus+ Lactobacillus sakei, and iii Staphylococcus carnosus+Pediococcus pentosaceus+Lactobacillus sakei. Analysis of microbiological, physico-chemical and lipase enzyme levels of samples were conducted until the 60th day. Interactions among the presence of lipolytic starter cultures, lipase enzyme levels and thiobarbituric acid reactive substances were also evaluated both in ripening and drying periods. There were apparent differences on microbiological and chemical properties between samples prepared with starters and control. It has been concluded that the use of lipolytic starter cultures in suitable combination would have positive effect on the acceleration of ripening and improvement of the quality of dry fermented sausages.

Plasmid fermentation process for DNA immunization applications.

Science.gov (United States)

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.

Nonlinear analysis and control of a continuous fermentation process

DEFF Research Database (Denmark)

Szederkényi, G.; Kristensen, Niels Rode; Hangos, K.M

2002-01-01

Different types of nonlinear controllers are designed and compared for a simple continuous bioreactor operating near optimal productivity. This operating point is located close to a fold bifurcation point. Nonlinear analysis of stability, controllability and zero dynamics is used to investigate o...... are recommended for the simple fermenter. Passivity based controllers have been found to be globally stable, not very sensitive to the uncertainties in the reaction rate and controller parameter but they require full nonlinear state feedback....

The Use of Lactic Acid Bacteria Starter Culture in the Production of Nunu, a Spontaneously Fermented Milk Product in Ghana

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Fortune Akabanda

2014-01-01

Full Text Available Nunu, a spontaneously fermented yoghurt-like product, is produced and consumed in parts of West Africa. A total of 373 predominant lactic acid bacteria (LAB previously isolated and identified from Nunu product were assessed in vitro for their technological properties (acidification, exopolysaccharides production, lipolysis, proteolysis and antimicrobial activities. Following the determination of technological properties, Lactobacillus fermentum 22-16, Lactobacillus plantarum 8-2, Lactobacillus helveticus 22-7, and Leuconostoc mesenteroides 14-11 were used as single and combined starter cultures for Nunu fermentation. Starter culture fermented Nunu samples were assessed for amino acids profile and rate of acidification and were subsequently evaluated for consumer acceptability. For acidification properties, 82%, 59%, 34%, and 20% of strains belonging to Lactobacillus helveticus, L. plantarum, L. fermentum, and Leu. mesenteriodes, respectively, demonstrated fast acidification properties. High proteolytic activity (>100 to 150 μg/mL was observed for 50% Leu. mesenteroides, 40% L. fermentum, 41% L. helveticus, 27% L. plantarum, and 10% Ent. faecium species. In starter culture fermented Nunu samples, all amino acids determined were detected in Nunu fermented with single starters of L. plantarum and L. helveticus and combined starter of L. fermntum and L. helveticus. Consumer sensory analysis showed varying degrees of acceptability for Nunu fermented with the different starter cultures.

Impact of a Microbial Cocktail Used as a Starter Culture on Cocoa Fermentation and Chocolate Flavor

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Igor Magalhães da Veiga Moreira

2017-05-01

Full Text Available Chocolate production suffered a vast impact with the emergence of the “witches’ broom” disease in cocoa plants. To recover cocoa production, many disease-resistant hybrid plants have been developed. However, some different cocoa hybrids produce cocoa beans that generate chocolate with variable quality. Fermentation of cocoa beans is a microbiological process that can be applied for the production of chocolate flavor precursors, leading to overcoming the problem of variable chocolate quality. The aim of this work was to use a cocktail of microorganisms as a starter culture on the fermentation of the ripe cocoa pods from PH15 cocoa hybrid, and evaluate its influence on the microbial communities present on the fermentative process on the compounds involved during the fermentation, and to perform the chocolate sensorial characterization. According to the results obtained, different volatile compounds were identified in fermented beans and in the chocolate produced. Bitterness was the dominant taste found in non-inoculated chocolate, while chocolate made with inoculated beans showed bitter, sweet, and cocoa tastes. 2,3-Butanediol and 2,3-dimethylpyrazine were considered as volatile compounds making the difference on the flavor of both chocolates. Saccharomyces cerevisiae UFLA CCMA 0200, Lactobacillus plantarum CCMA 0238, and Acetobacter pasteurianus CCMA 0241 are proposed as starter cultures for cocoa fermentation.

Impact of a Microbial Cocktail Used as a Starter Culture on Cocoa Fermentation and Chocolate Flavor.

Science.gov (United States)

Magalhães da Veiga Moreira, Igor; de Figueiredo Vilela, Leonardo; da Cruz Pedroso Miguel, Maria Gabriela; Santos, Cledir; Lima, Nelson; Freitas Schwan, Rosane

2017-05-09

Chocolate production suffered a vast impact with the emergence of the "witches' broom" disease in cocoa plants. To recover cocoa production, many disease-resistant hybrid plants have been developed. However, some different cocoa hybrids produce cocoa beans that generate chocolate with variable quality. Fermentation of cocoa beans is a microbiological process that can be applied for the production of chocolate flavor precursors, leading to overcoming the problem of variable chocolate quality. The aim of this work was to use a cocktail of microorganisms as a starter culture on the fermentation of the ripe cocoa pods from PH15 cocoa hybrid, and evaluate its influence on the microbial communities present on the fermentative process on the compounds involved during the fermentation, and to perform the chocolate sensorial characterization. According to the results obtained, different volatile compounds were identified in fermented beans and in the chocolate produced. Bitterness was the dominant taste found in non-inoculated chocolate, while chocolate made with inoculated beans showed bitter, sweet, and cocoa tastes. 2,3-Butanediol and 2,3-dimethylpyrazine were considered as volatile compounds making the difference on the flavor of both chocolates. Saccharomyces cerevisiae UFLA CCMA 0200, Lactobacillus plantarum CCMA 0238, and Acetobacter pasteurianus CCMA 0241 are proposed as starter cultures for cocoa fermentation.

Coupling limonene formation and oxyfunctionalization by mixed-culture resting cell fermentation.

Science.gov (United States)

Willrodt, Christian; Hoschek, Anna; Bühler, Bruno; Schmid, Andreas; Julsing, Mattijs K

2015-09-01

Metabolic engineering strategies mark a milestone for the fermentative production of bulk and fine chemicals. Yet, toxic products and volatile reaction intermediates with low solubilities remain challenging. Prominent examples are artificial multistep pathways like the production of perillyl acetate (POHAc) from glucose via limonene. For POHAc, these limitations can be overcome by mixed-culture fermentations. A limonene biosynthesis pathway and cytochrome P450 153A6 (CYP153A6) as regioselective hydroxylase are used in two distinct recombinant E. coli. POHAc formation from glucose in one recombinant cell was hindered by ineffective coupling of limonene synthesis and low rates of oxyfunctionalization. The optimization of P450 gene expression led to the formation of 6.20 ± 0.06 mg gcdw (-1) POHAc in a biphasic batch cultivation with glucose as sole carbon and energy source. Increasing the spatial proximity between limonene synthase and CYP153A6 by a genetic fusion of both enzymes changed the molar limonene/POHAc ratio from 3.2 to 1.6. Spatial separation of limonene biosynthesis from its oxyfunctionalization improved POHAc concentration 3.3-fold to 21.7 mg L(-1) as compared to a biphasic fermentation. Mixed-cultures of E. coli BL21 (DE3) containing the limonene biosynthesis pathway and E. coli MG1655 harboring either CYP153A6, or alternatively a cymene monooxygenase, showed POHAc formation rates of 0.06 or 0.11 U gcdw (-1) , respectively. This concept provides a novel framework for fermentative syntheses involving toxic, volatile, or barely soluble compounds or pathway intermediates. © 2015 Wiley Periodicals, Inc.

Effect of yeast culture and Aspergillus oryzae fermentation extract on ruminal characteristics and nutrient digestibility.

Science.gov (United States)

Wiedmeier, R D; Arambel, M J; Walters, J L

1987-10-01

Four nonpregnant and nonlactating Holstein cows fitted with ruminal fistulas were assigned to each of four diets in a 4 X 4 Latin square design. Dietary treatments were 1) basal diet containing 50% concentrate; 2) basal diet plus 90 g/d yeast culture; 3) basal diet plus 2.63 g/d Aspergillus oryzae fermentation extract; 4) basal diet plus 90 g/d of A. oryzae fermentation extract and yeast culture. Cows were fed diets at a rate of 86 g DM/kg BW.75 for 14 d adaptation followed by an 8-d collection period. Digestibility of dry matter was increased by A. oryzae and A. oryzae and yeast culture combination treatments. Digestibility of CP was increased regardless of fungal culture addition. Hemicellulose digestibility, percent ruminal cellulolytic organisms, and acetate to propionate ratio were increased by the addition of fungal supplements.

Continuous culture apparatus and methodology

International Nuclear Information System (INIS)

Conway, H.L.

1975-01-01

At present, we are investigating the sorption of potentially toxic trace elements by phytoplankton under controlled laboratory conditions. Continuous culture techniques were used to study the mechanism of the sorption of the trace elements by unialgal diatom populations and the factors influencing this sorption. Continuous culture methodology has been used extensively to study bacterial kinetics. It is an excellent technique for obtaining a known physiological state of phytoplankton populations. An automated method for the synthesis of continuous culture medium for use in these experiments is described

Yeasts Diversity in Fermented Foods and Beverages

Science.gov (United States)

Tamang, Jyoti Prakash; Fleet, Graham H.

People across the world have learnt to culture and use the essential microorganisms for production of fermented foods and alcoholic beverages. A fermented food is produced either spontaneously or by adding mixed/pure starter culture(s). Yeasts are among the essential functional microorganisms encountered in many fermented foods, and are commercially used in production of baker's yeast, breads, wine, beer, cheese, etc. In Asia, moulds are predominant followed by amylolytic and alcohol-producing yeasts in the fermentation processes, whereas in Africa, Europe, Australia and America, fermented products are prepared exclusively using bacteria or bacteria-yeasts mixed cultures. This chapter would focus on the varieties of fermented foods and alcoholic beverages produced by yeasts, their microbiology and role in food fermentation, widely used commercial starters (pilot production, molecular aspects), production technology of some common commercial fermented foods and alcoholic beverages, toxicity and food safety using yeasts cultures and socio-economy

Examination of protein degradation in continuous flow, microbial electrolysis cells treating fermentation wastewater

KAUST Repository

Nam, Joo-Youn; Yates, Matthew D.; Zaybak, Zehra; Logan, Bruce E.

2014-01-01

© 2014 Elsevier Ltd. Cellulose fermentation wastewaters (FWWs) contain short chain volatile fatty acids and alcohols, but they also have high concentrations of proteins. Hydrogen gas production from FWW was examined using continuous flow microbial

Use of Gelidium amansii as a promising resource for bioethanol: a practical approach for continuous dilute-acid hydrolysis and fermentation.

Science.gov (United States)

Park, Jeong-Hoon; Hong, Ji-Yeon; Jang, Hyun Chul; Oh, Seung Geun; Kim, Sang-Hyoun; Yoon, Jeong-Jun; Kim, Yong Jin

2012-03-01

A facile continuous method for dilute-acid hydrolysis of the representative red seaweed species, Gelidium amansii was developed and its hydrolysate was subsequently evaluated for fermentability. In the hydrolysis step, the hydrolysates obtained from a batch reactor and a continuous reactor were systematically compared based on fermentable sugar yield and inhibitor formation. There are many advantages to the continuous hydrolysis process. For example, the low melting point of the agar component in G. amansii facilitates improved raw material fluidity in the continuous reactor. In addition, the hydrolysate obtained from the continuous process delivered a high sugar and low inhibitor concentration, thereby leading to both high yield and high final ethanol titer in the fermentation process. Copyright © 2011 Elsevier Ltd. All rights reserved.

Change of lactose content after milk fermentation using various microbial cultures

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Ivana Vinko

2011-06-01

Full Text Available The purpose of this study was to determine lactose and lactic acid content and acidity changes in typified milk prior to fermentation and in dairy products on 1st and 28th day of their storage at 8 °C in cold environment. In this study 5 different dairy products were observed: yogurt, extra lactose yogurt, bifido milk, sour cream and sour milk. The enzymatic method for determination of lactose has been used. The biggest change in lactose and lactic acid content, according to study results, has happened in the process of fermentation, as expected. About 16-20 % of lactose has been converted by mesophilus, while significantly bigger part (round 30 % of lactose to lactic acid has been converted by thermophilus. The smallest part of lactose conversion was performed by Bifidobacterium therapy culture (just 15 % after the first day and 19 % on 28th day of cold storage which is due to the greater adjustment period of Bifidobacterium in milk for lactose fermentation.

Impact of sequential co-culture fermentations on flavour characters of Solaris wines

DEFF Research Database (Denmark)

Liu, Jing; Arneborg, Nils; Toldam-Andersen, Torben Bo

2017-01-01

-phenylethyl acetate. This co-culture fermentation also produced higher amounts of ethyl acetate and acetic acid, reducing the possibility of its use in winemaking. Three Metschnikowia strains, a M. chrysoperlae strain and two M. fructicola strains, gave a comparable production of volatile compounds...

Oxygen availability and strain combination modulate yeast growth dynamics in mixed culture fermentations of grape must with Starmerella bacillaris and Saccharomyces cerevisiae.

Science.gov (United States)

Englezos, Vasileios; Cravero, Francesco; Torchio, Fabrizio; Rantsiou, Kalliopi; Ortiz-Julien, Anne; Lambri, Milena; Gerbi, Vincenzo; Rolle, Luca; Cocolin, Luca

2018-02-01

Starmerella bacillaris (synonym Candida zemplinina) is a non-Saccharomyces yeast that has been proposed as a co-inoculant of selected Saccharomyces cerevisiae strains in mixed culture fermentations to enhance the analytical composition of the wines. In order to acquire further knowledge on the metabolic interactions between these two species, in this study we investigated the impact of oxygen addition and combination of Starm. bacillaris with S. cerevisiae strains on the microbial growth and metabolite production. Fermentations were carried out under two different conditions of oxygen availability. Oxygen availability and strain combination clearly influenced the population dynamics throughout the fermentation. Oxygen concentration increased the survival time of Starm. bacillaris and decreased the growth rate of S. cerevisiae strains in mixed culture fermentations, whereas it did not affect the growth of the latter in pure culture fermentations. This study reveals new knowledge about the influence of oxygen availability on the successional evolution of yeast species during wine fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bifurcation analysis of a product inhibition model of a continuous fermentation process

Energy Technology Data Exchange (ETDEWEB)

Lenbury, Y; Chiaranai, C

1987-03-01

A product inhibition model of a continuous fermentation process is considered. If the yield term is a variable function of ethanol concentration, oscillation in the cell and ethanol concentrations is shown to be a Hopf bifurcation in the underlying system of nonlinear, ordinary differential equations which comprises the model.

Steady-state and transient-state analyses of aerobic fermentation in Saccharomyces kluyveri

DEFF Research Database (Denmark)

Møller, Kasper; Bro, Christoffer; Piskur, Jure

2002-01-01

Some yeasts, such as Saccharomyces cerevisiae, produce ethanol at fully aerobic conditions, whereas other yeasts, such as Kluyveromyces lactis, do not. In this study we investigated the occurrence of aerobic alcoholic fermentation in the petite-negative yeast Saccharomyces kluyveri that is only...... distantly related to S. cerevisiae. In aerobic glucose-limited continuous cultures of S. kluyveri, two growth regimens were observed: at dilution rates below 0.5 h(-1) the metabolism was purely respiratory, and at dilution rates above 0.5 h-1 the metabolism was respiro-fermentative. The dilution rate...... a delay of 20-50 min (depending on culture conditions prior to the pulse), which is in contrast to S. cerevisiae that ferments immediately after glucose addition....

Cross-cultural comparisons among the sensory characteristics of fermented soybean using Korean and Japanese descriptive analysis panels.

Science.gov (United States)

Chung, L; Chung, S-J

2007-11-01

One of the most important initial steps in exporting a food product to another country from the R&D perspective is to describe and translate the sensory characteristics of a food product appropriately into the language of the target country. The objectives of this study were to describe and compare the sensory characteristics of Korean and Japanese style fermented soybean products, and to cross-culturally compare the lexicons of the identical product generated by the Korean and Japanese panelists. Four types of Korean and 4 types of Japanese style fermented soybean consisting of whole bean type and paste type were analyzed. Ten Korean and 9 Japanese panelists were recruited in Korea. Two separate descriptive analyses were conducted, with the panelists differing in their country of origin. Each group was trained, developed lexicon, and conducted descriptive analysis independently. Analysis of variance and various multivariate analyses were applied to delineate the sensory characteristics of the samples and to compare the cross-cultural differences in the usage of lexicon. The Korean and Japanese panelists generated 48 and 36 sensory attributes, respectively. Cross-cultural consensus was shown for evaluating the whole bean type fermented soybean and white miso, which were relatively distinctive samples. However, for the less distinctive samples, the panelists tend to rate higher in negative attributes for the fermented soybeans that originated from the other country. The Japanese panelists grouped the samples by their country of origin and soy sauce flavor was the main attribute for cross-cultural differentiation. However, the Korean panelists did not make a cross-cultural distinction among the samples.

Continuous acetone-ethanol-butanol fermentation by immobilized cells of Clostridium acetobutylicum

Energy Technology Data Exchange (ETDEWEB)

Badr, H.R.; Toledo, R.; Hamdy, M.K. [University of Georgia, Athens (Greece). Food Science and Technology Dept.

2001-07-01

Eight Clostridium acetobutylicum strains were examined for {alpha}-amylase and strains B-591, B-594 and P-262 had the highest activities. Defibered-sweet-potato-slurry (DSPS), containing 39.7 g starch l{sup -1}, supplemented with potassium phosphate (1.0 g l{sup -1}), cysteine-HCl (5.0 g l{sup -1}), the antifoam (polypropylene glycol, 0.1 mg ml{sup -1}), was used a continuous feedstock (FS) to a multistage bioreactor system for acetone-ethanol-butanol (AEB) fermentation. The system consisted on four columns (three vertical and one near horizontal) packed with beads containing immobilized cells of C. acetobutylicum P-262. When DSPS was pumped into the bioreactor system, at a flow rate of 2.36 ml min{sup -1}, the effluent has 7.73 g solvents l{sup -1} (1.56, acetone; 0.65, ethanol; 5.52 g, butanol) and no starch. Productivity of total solvents synthesized during continuous operation were 1.0 g 1{sup -1}h{sup -1} and 19.5 % yield compared to 0.12 g l{sup -1}h{sup -1} with 29% yield using the batch system. We proposed using DSPS for AEB fermentation in a continuous mode with immobilized P-262 cells that are active amylase producers which will lead to cost reduction compared to the batch system. (Author)

Mathematical model of gluconic acid fermentation by Aspergillus niger

Energy Technology Data Exchange (ETDEWEB)

Takamatsu, T.; Shioya, S.; Furuya, T.

1981-11-01

A mathematical model for the study of gluconic acid fermentation by Aspergillus niger has been developed. The model has been deduced from the basic biological concept of multicellular filamentous microorganisms, i.e. cell population balance. It can be used to explain the behaviour of both batch and continuous cultures, even when in a lag phase. A new characteristic, involving the existence of dual equilibrium stages during fermentation, has been predicted using this mathematical model. (Refs. 6).

Combination of culture-independent and culture-dependent molecular methods for the determination of bacterial community of iru, a fermented Parkia biglobosa seeds.

Directory of Open Access Journals (Sweden)

Gbenga Adedeji Adewumi

2013-01-01

Full Text Available In this study, bacterial composition of iru produced by natural, uncontrolled fermentation of Parkia biglobosa seeds was assessed using culture-independent method in combination with culture-based genotypic typing techniques. PCR-denaturing gradient gel electrophoresis (DGGE revealed similarity in DNA fragments with the two DNA extraction methods used and confirmed bacterial diversity in the sixteen iru samples from different production regions. DNA sequencing of the highly variable V3 region of the 16S rRNA genes obtained from PCR-DGGE identified species related to Bacillus subtilis as consistent bacterial species in the fermented samples, while other major bands were identified as close relatives of Staphylococcus vitulinus, Morganella morganii, B. thuringiensis, Staphylococcus saprophyticus, Tetragenococcus halophilus, Ureibacillus thermosphaericus, Brevibacillus parabrevis, Salinicoccus jeotgali, Brevibacterium sp. and Uncultured bacteria clones. Bacillus species were cultured as potential starter cultures and clonal relationship of different isolates determined using amplified ribosomal DNA restriction analysis (ARDRA combined with 16S-23S rRNA gene internal transcribed spacer (ITS PCR amplification, restriction analysis (ITS-PCR-RFLP and randomly amplified polymorphic DNA (RAPD-PCR. This further discriminated Bacillus subtilis and its variants from food-borne pathogens such as Bacillus cereus and suggested the need for development of controlled fermentation processes and good manufacturing practices (GMP for iru production to achieve product consistency, safety quality and improved shelf life.

Optimization of culture conditions for gamma-aminobutyric acid production in fermented adzuki bean milk

Directory of Open Access Journals (Sweden)

Hung Yi Song

2018-01-01

Full Text Available γ-Aminobutyric acid (GABA, a nonprotein amino acid, is widely distributed in nature and fulfills several physiological functions. In this study, various lactic acid strains commonly used to produce fermented milk products were inoculated into adzuki bean milk for producing GABA. The high GABA producing strain was selected in further experiment to improve the GABA production utilizing culture medium optimization. The results demonstrated that adzuki bean milk inoculated with Lactobacillus rhamnosus GG increased GABA content from 0.05 mg/mL to 0.44 mg/mL after 36 hours of fermentation, which showed the greatest elevation in this study. Furthermore, the optimal cultural condition to adzuki bean milk inoculated with L. rhamnosus GG to improve the GABA content was performed using response surface methodology. The results showed that GABA content was dependent on the addition of galactose, monosodium glutamate, and pyridoxine with which the increasing ratios of GABA were 23–38%, 24–68%, and 8–36%, respectively. The optimal culture condition for GABA production of adzuki bean milk was found at the content of 1.44% galactose, 2.27% monosodium glutamate, and 0.20% pyridoxine. Under the optimal cultural condition, the amount of GABA produced in the fermented adzuki bean milk was 1.12 mg/mL, which was 22.4-fold higher than that of the unfermented adzuki bean milk (0.05 mg/100 mL. The results suggested that the optimized cultural condition of adzuki bean milk inoculated with L. rhamnosus GG can increase GABA content for consumers as a daily supplement as suggested.

Modeling of rheological characteristics of the fermented dairy products obtained by novel and traditional starter cultures.

Science.gov (United States)

Vukić, Dajana V; Vukić, Vladimir R; Milanović, Spasenija D; Ilicić, Mirela D; Kanurić, Katarina G

2018-06-01

Tree different fermented dairy products obtained by conventional and non-conventional starter cultures were investigated in this paper. Textural and rheological characteristics as well as chemical composition during 21 days of storage were analysed and subsequent data processing was performed by principal component analysis. The analysis of samples` flow behaviour was focused on their time dependent properties. Parameters of Power law model described flow behaviour of samples depended on used starter culture and days of storage. The Power law model was applied successfully to describe the flow of the fermented milk, which had characteristics of shear thinning and non-Newtonian fluid behaviour.

Analysis of microbial community variation during the mixed culture fermentation of agricultural peel wastes to produce lactic acid.

Science.gov (United States)

Liang, Shaobo; Gliniewicz, Karol; Gerritsen, Alida T; McDonald, Armando G

2016-05-01

Mixed cultures fermentation can be used to convert organic wastes into various chemicals and fuels. This study examined the fermentation performance of four batch reactors fed with different agricultural (orange, banana, and potato (mechanical and steam)) peel wastes using mixed cultures, and monitored the interval variation of reactor microbial communities with 16S rRNA genes using Illumina sequencing. All four reactors produced similar chemical profile with lactic acid (LA) as dominant compound. Acetic acid and ethanol were also observed with small fractions. The Illumina sequencing results revealed the diversity of microbial community decreased during fermentation and a community of largely lactic acid producing bacteria dominated by species of Lactobacillus developed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Complex microbiota of a Chinese "Fen" liquor fermentation starter (Fen-Daqu), revealed by culture-dependent and culture-independent methods

NARCIS (Netherlands)

Zheng, X.; Zheng, Y.; Han, B.; Zwietering, M.H.; Samson, R.A.; Boekhout, T.; Nout, M.J.R.

2012-01-01

Daqu is a traditional fermentation starter that is used for Chinese liquor production. Although partly mechanized, its manufacturing process has remained traditional. We investigated the microbial diversity of Fen-Daqu, a starter for light-flavour liquor, using combined culture-dependent and

Change in enzyme production by gradually drying culture substrate during solid-state fermentation.

Science.gov (United States)

Ito, Kazunari; Gomi, Katsuya; Kariyama, Masahiro; Miyake, Tsuyoshi

2015-06-01

The influence of drying the culture substrate during solid-state fermentation on enzyme production was investigated using a non-airflow box. The drying caused a significant increase in enzyme production, while the mycelium content decreased slightly. This suggests that changes in the water content in the substrate during culture affect enzyme production in fungi. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Integrative modelling of pH-dependent enzyme activity and transcriptomic regulation of the acetone–butanol–ethanol fermentation of Clostridium acetobutylicum in continuous culture

Science.gov (United States)

Millat, Thomas; Janssen, Holger; Bahl, Hubert; Fischer, Ralf-Jörg; Wolkenhauer, Olaf

2013-01-01

Summary In a continuous culture under phosphate limitation the metabolism of Clostridium acetobutylicum depends on the external pH level. By comparing seven steady-state conditions between pH 5.7 and pH 4.5 we show that the switch from acidogenesis to solventogenesis occurs between pH 5.3 and pH 5.0 with an intermediate state at pH 5.1. Here, an integrative study is presented investigating how a changing external pH level affects the clostridial acetone–butanol–ethanol (ABE) fermentation pathway. This is of particular interest as the biotechnological production of n-butanol as biofuel has recently returned into the focus of industrial applications. One prerequisite is the furthering of the knowledge of the factors determining the solvent production and their integrative regulations. We have mathematically analysed the influence of pH-dependent specific enzyme activities of branch points of the metabolism on the product formation. This kinetic regulation was compared with transcriptomic regulation regarding gene transcription and the proteomic profile. Furthermore, both regulatory mechanisms were combined yielding a detailed projection of their individual and joint effects on the product formation. The resulting model represents an important platform for future developments of industrial butanol production based on C. acetobutylicum. PMID:23332010

Fermented sausage production using E. faecium as starter culture: Physicochemical and microbiological profile, sensorial acceptance and cellular viability

Directory of Open Access Journals (Sweden)

Catharina Calochi Pires de Carvalho

2017-09-01

Full Text Available Fermented sausages are defined as a mixture of lean meat and fat, curing salts, sucrose and spices, stuffed in a natural or artificial casing and submitted to fermentation and air-drying process. Starter culture and ripening process may affect the quality and acceptability of the final product. Current research evaluates the use of Enterococcus faecium as starter culture in fermented sausage production and its physicochemical and microbiological profile during maturation process, coupled to sausage sensory acceptance after ripening. Enterococcus faecium showed 10.9 log CFU g-1 and remained viable after the ripening period with 8.32 log CFU g-1. Fermented sausage was monitored during the ripening period by physicochemical (pH control, water activity and weight loss and microbiological (analysis of coagulase-positive Staphylococcus, coliforms and Salmonella spp. analyses. All tests complied with standards established by Brazilian legislation and did not interfere in final product quality. Results showed that E. faecium was resistant to curing salt and sodium chloride, maintaining its viability during ripening and conferring beneficial effects on fermented sausage technological characteristics. E. faecium also proved to be in vitro resistant to simulate passage through the human digestive tract. Fermented sausage containing E. faecium had better sensory acceptance than commercial sausage evaluated.

Lactic acid production with undefined mixed culture fermentation of potato peel waste.

Science.gov (United States)

Liang, Shaobo; McDonald, Armando G; Coats, Erik R

2014-11-01

Potato peel waste (PPW) as zero value byproduct generated from food processing plant contains a large quantity of starch, non-starch polysaccharide, lignin, protein, and lipid. PPW as one promising carbon source can be managed and utilized to value added bioproducts through a simple fermentation process using undefined mixed cultures inoculated from wastewater treatment plant sludge. A series of non-pH controlled batch fermentations under different conditions such as pretreatment process, enzymatic hydrolysis, temperature, and solids loading were studied. Lactic acid (LA) was the major product, followed by acetic acid (AA) and ethanol under fermentation conditions without the presence of added hydrolytic enzymes. The maximum yields of LA, AA, and ethanol were respectively, 0.22 g g(-1), 0.06 g g(-1), and 0.05 g g(-1). The highest LA concentration of 14.7 g L(-1) was obtained from a bioreactor with initial solids loading of 60 g L(-1) at 35°C. Copyright © 2014 Elsevier Ltd. All rights reserved.

Inoculation of starter cultures in a semi-dry coffee (Coffea arabica) fermentation process.

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Evangelista, Suzana Reis; Miguel, Maria Gabriela da Cruz Pedrozo; Cordeiro, Cecília de Souza; Silva, Cristina Ferreira; Pinheiro, Ana Carla Marques; Schwan, Rosane Freitas

2014-12-01

The aim of this study was to evaluate the use of yeasts as starter cultures in coffee semi-dry processing. Arabica coffee was inoculated with one of the following starter cultures: Saccharomyces cerevisiae UFLA YCN727, S. cerevisiae UFLA YCN724, Candida parapsilosis UFLA YCN448 and Pichia guilliermondii UFLA YCN731. The control was not inoculated with a starter culture. Denaturing gradient gel electrophoresis (DGGE) was used to assess the microbial population, and organic acids and volatile compounds were quantified by HPLC and HS-SPME/GC, respectively. Sensory analyses were evaluated using the Temporal Dominance of Sensations (TDS). DGGE analysis showed that the inoculated yeasts were present throughout the fermentation. Other yeast species were also detected, including Debaryomyces hansenii, Cystofilobasidium ferigula and Trichosporon cavernicola. The bacterial population was diverse and was composed of the following genera: Weissella, Leuconostoc, Gluconobacter, Pseudomonas, Pantoea, Erwinia and Klebsiella. Butyric and propionic acids, were not detected in any treatment A total of 47 different volatiles compounds have been identified. The coffee inoculated with yeast had a caramel flavor that was not detected in the control, as assessed by TDS. The use of starter cultures during coffee fermentation is an interesting alternative for obtaining a beverage quality with distinctive flavor. Copyright © 2014 Elsevier Ltd. All rights reserved.

Application of near-infrared spectroscopy for monitoring and control of cell culture and fermentation

DEFF Research Database (Denmark)

Cervera Padrell, Albert Emili; Petersen, Nanna; Eliasson Lantz, Anna

2009-01-01

of chemometric models built for interpretation of the spectra, thus impairing the analyte concentration predictions. The aim of this review was to provide an overview of necessary conditions and challenges that one has to face when developing a NIR application for monitoring of cell culture or fermentation...... processes. Important practical aspects are introduced, such as sampling, modeling of biomass concentration, influence of microorganism morphology on the spectra, effects of the hydrodynamic conditions in the fermenter, temperature influence, instrument settings, and signal optimization. Several examples......Near-infrared (NIR) spectroscopy can potentially provide on-line information on substrate, biomass, product, and metabolite concentrations in fermentation processes, which could be useful for improved monitoring or control. However, several factors can negatively influence the quality...

Yeast-yeast interactions revealed by aromatic profile analysis of Sauvignon Blanc wine fermented by single or co-culture of non-Saccharomyces and Saccharomyces yeasts.

Science.gov (United States)

Sadoudi, Mohand; Tourdot-Maréchal, Raphaëlle; Rousseaux, Sandrine; Steyer, Damien; Gallardo-Chacón, Joan-Josep; Ballester, Jordi; Vichi, Stefania; Guérin-Schneider, Rémi; Caixach, Josep; Alexandre, Hervé

2012-12-01

There has been increasing interest in the use of selected non-Saccharomyces yeasts in co-culture with Saccharomyces cerevisiae. The main reason is that the multistarter fermentation process is thought to simulate indigenous fermentation, thus increasing wine aroma complexity while avoiding the risks linked to natural fermentation. However, multistarter fermentation is characterised by complex and largely unknown interactions between yeasts. Consequently the resulting wine quality is rather unpredictable. In order to better understand the interactions that take place between non-Saccharomyces and Saccharomyces yeasts during alcoholic fermentation, we analysed the volatile profiles of several mono-culture and co-cultures. Candida zemplinina, Torulaspora delbrueckii and Metschnikowia pulcherrima were used to conduct fermentations either in mono-culture or in co-culture with S. cerevisiae. Up to 48 volatile compounds belonging to different chemical families were quantified. For the first time, we show that C. zemplinina is a strong producer of terpenes and lactones. We demonstrate by means of multivariate analysis that different interactions exist between the co-cultures studied. We observed a synergistic effect on aromatic compound production when M. pulcherrima was in co-culture with S. cerevisiae. However a negative interaction was observed between C. zemplinina and S. cerevisiae, which resulted in a decrease in terpene and lactone content. These interactions are independent of biomass production. The aromatic profiles of T. delbrueckii and S. cerevisiae in mono-culture and in co-culture are very close, and are biomass-dependent, reflecting a neutral interaction. This study reveals that a whole family of compounds could be altered by such interactions. These results suggest that the entire metabolic pathway is affected by these interactions. Copyright © 2012 Elsevier Ltd. All rights reserved.

The impact of oxygen on the final alcohol content of wine fermented by a mixed starter culture.

Science.gov (United States)

Morales, Pilar; Rojas, Virginia; Quirós, Manuel; Gonzalez, Ramon

2015-05-01

We have developed a wine fermentation procedure that takes advantage of the metabolic features of a previously characterized Metschnikowia pulcherrima strain in order to reduce ethanol production. It involves the use of M. pulcherrima/Saccharomyces cerevisiae mixed cultures, controlled oxygenation conditions during the first 48 h of fermentation, and anaerobic conditions thereafter. The influence of different oxygenation regimes and initial inoculum composition on yeast physiology and final ethanol content was studied. The impact of oxygenation on yeast physiology goes beyond the first aerated step and influences yields and survival rates during the anaerobic stage. The activity of M. pulcherrima in mixed oxygenated cultures resulted in a clear reduction in ethanol yield, as compared to S. cerevisiae. Despite relatively low initial cell numbers, S. cerevisiae always predominated in mixed cultures by the end of the fermentation process. Strain replacement was faster under low oxygenation levels. M. pulcherrima confers an additional advantage in terms of dissolved oxygen, which drops to zero after a few hours of culture, even under highly aerated conditions, and this holds true for mixed cultures. Alcohol reduction values about 3.7 % (v/v) were obtained for mixed cultures under high aeration, but they were associated to unacceptable volatile acidity levels. In contrast, under optimized conditions, only 0.35 g/L acetic acid was produced, for an alcohol reduction of 2.2 % (v/v), and almost null dissolved oxygen during the process.

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

Science.gov (United States)

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.

Comparison of fermentation profiles between lupine and soybean by Aspergillus oryzae and Aspergillus sojae in solid-state culture systems

NARCIS (Netherlands)

Sardjono; Zhu, Y.; Knol, W.

1998-01-01

To explore the possibilities of using lupine as a soybean replacement in fermented foods, fermentation profiles of lupine and soybean by Aspergillus oryzae and A. sojae, respectively, in a solid-state culture were compared. Biomass, spore concentration, oxygen consumption rate, carbon dioxide

Continuous dry fermentation of swine manure for biogas production.

Science.gov (United States)

Chen, Chuang; Zheng, Dan; Liu, Gang-Jin; Deng, Liang-Wei; Long, Yan; Fan, Zhan-Hui

2015-04-01

A down plug-flow anaerobic reactor (DPAR) was designed for the feasibility study on continuous dry fermentation of swine manure without any additional stirring. Using fresh swine manure as the feedstock with TS concentration (w/w) of 20%, 25%, 30%, and 35%, stable volumetric biogas production rates of 2.40, 1.92, 0.911, and 0.644L · (Ld)(-1) and biogas yields of 0.665, 0.532, 0.252, and 0.178 L g(-)(1)VS were obtained respectively, and the TS degradation rates were 46.5%, 45.4%, 53.2%, and 55.6%, respectively. With the increase of feedstock TS concentration, the concentration of ammonia nitrogen grew up to the maximum value of 3500 mg L(-1). Biogas production was obviously inhibited when the concentration of ammonia nitrogen was above 3000 mg L(-1). The maximal volumetric biogas production rate of 2.34 L ·(Ld)(-1) and biogas yield of 0.649 L g(-1)VS were obtained with TS concentration of 25% at 25°C without inhibition. Liquidity experiments showed that TS concentration of digestate could be less than 15.8%, and the flow rate of digestate more than 0.98 m s(-1) when the feedstock TS concentration was less than 35%, which indicated the digestate could be easily discharged from a DPAR. Therefore, it is feasible to conduct a continuous dry fermentation in a DPAR using fresh swine manure as the feedstock with TS concentration less than 35%, whereas the feedstock TS concentration should not exceed 30% to achieve the maximal biogas production rate and biogas yield. Copyright © 2015 Elsevier Ltd. All rights reserved.

New potentially antihypertensive peptides liberated in milk during fermentation with selected lactic acid bacteria and kombucha cultures.

Science.gov (United States)

Elkhtab, Ebrahim; El-Alfy, Mohamed; Shenana, Mohamed; Mohamed, Abdelaty; Yousef, Ahmed E

2017-12-01

Compounds with the ability to inhibit angiotensin-converting enzyme (ACE) are used medically to treat human hypertension. The presence of such compounds naturally in food is potentially useful for treating the disease state. The goal of this study was to screen lactic acid bacteria, including species commonly used as dairy starter cultures, for the ability to produce new potent ACE-inhibiting peptides during milk fermentation. Strains of Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus helveticus, Lactobacillus paracasei, Lactococcus lactis, Leuconostoc mesenteroides, and Pediococcus acidilactici were tested in this study. Additionally, a symbiotic consortium of yeast and bacteria, used commercially to produce kombucha tea, was tested. Commercially sterile milk was inoculated with lactic acid bacteria strains and kombucha culture and incubated at 37°C for up to 72 h, and the liberation of ACE-inhibiting compounds during fermentation was monitored. Fermented milk was centrifuged and the supernatant (crude extract) was subjected to ultrafiltration using 3- and 10-kDa cut-off filters. Crude and ultrafiltered extracts were tested for ACE-inhibitory activity. The 10-kDa filtrate resulting from L. casei ATCC 7469 and kombucha culture fermentations (72 h) showed the highest ACE-inhibitory activity. Two-step purification of these filtrates was done using HPLC equipped with a reverse-phase column. Analysis of HPLC-purified fractions by liquid chromatography-mass spectrometry/mass spectrometry identified several new peptides with potent ACE-inhibitory activities. Some of these peptides were synthesized, and their ACE-inhibitory activities were confirmed. Use of organisms producing these unique peptides in food fermentations could contribute positively to human health. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Cosmeceutical potentials and bioactive compounds of rice bran fermented with single and mix culture of Aspergillus oryzae and Rhizopus oryzae

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Dang Lelamurni Abd Razak

2017-04-01

Full Text Available In the present study, rice bran, one of the most abundant agricultural by-products in Malaysia, was fermented with single and mixed cultures of Aspergillus oryzae and Rhizopus oryzae. The fermented rice bran extracts were tested for their functional properties and compared to the non-fermented counterparts. Antioxidant activities as well as phenolics and organic acid contents were evaluated. Skincare-related functionalities were also tested by evaluating tyrosinase and elastase inhibition activities. Tyrosinase inhibition activity, measured to determine the anti-pigmentation effect of extracts, was found to be the highest in the extract of rice bran fermented with A. oryzae (56.18% compared to other extracts. In determining the anti-aging effect of fermented rice bran extracts, the same extract showed the highest elastase inhibition activity with a value of 60.52%. Antioxidant activities were found to be highest in the mix-cultured rice bran extract. The results of phenolic and organic acid content were varied; the major phenolic acid detected was ferulic acid with a value of 43.19 μg/ml in the mix-cultured rice bran extract. On the other hand, citric acid was the major organic acid detected, with the highest content found in the same extract (214.6 mg/g. The results of this study suggest that the fermented rice bran extracts may have the potential to be further exploited as ingredients in cosmetics as well as in antioxidant-rich products.

Unraveling microbial ecology of industrial-scale Kombucha fermentations by metabarcoding and culture-based methods.

Science.gov (United States)

Coton, Monika; Pawtowski, Audrey; Taminiau, Bernard; Burgaud, Gaëtan; Deniel, Franck; Coulloumme-Labarthe, Laurent; Fall, Abdoulaye; Daube, Georges; Coton, Emmanuel

2017-05-01

Kombucha, historically an Asian tea-based fermented drink, has recently become trendy in Western countries. Producers claim it bears health-enhancing properties that may come from the tea or metabolites produced by its microbiome. Despite its long history of production, microbial richness and dynamics have not been fully unraveled, especially at an industrial scale. Moreover, the impact of tea type (green or black) on microbial ecology was not studied. Here, we compared microbial communities from industrial-scale black and green tea fermentations, still traditionally carried out by a microbial biofilm, using culture-dependent and metabarcoding approaches. Dominant bacterial species belonged to Acetobacteraceae and to a lesser extent Lactobacteriaceae, while the main identified yeasts corresponded to Dekkera, Hanseniaspora and Zygosaccharomyces during all fermentations. Species richness decreased over the 8-day fermentation. Among acetic acid bacteria, Gluconacetobacter europaeus, Gluconobacter oxydans, G. saccharivorans and Acetobacter peroxydans emerged as dominant species. The main lactic acid bacteria, Oenococcus oeni, was strongly associated with green tea fermentations. Tea type did not influence yeast community, with Dekkera bruxellensis, D. anomala, Zygosaccharomyces bailii and Hanseniaspora valbyensis as most dominant. This study unraveled a distinctive core microbial community which is essential for fermentation control and could lead to Kombucha quality standardization. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Evolutionary engineering to enhance starter culture performance in food fermentations.

Science.gov (United States)

Bachmann, Herwig; Pronk, Jack T; Kleerebezem, Michiel; Teusink, Bas

2015-04-01

Microbial starter cultures are essential for consistent product quality and functional properties such as flavor, texture, pH or the alcohol content of various fermented foods. Strain improvement programs to achieve desired properties in starter cultures are diverse, but developments in next-generation sequencing lead to an increased interest in evolutionary engineering of desired phenotypes. We here discuss recent developments of strain selection protocols and how computational approaches can assist such experimental design. Furthermore the analysis of evolved phenotypes and possibilities with complex consortia are highlighted. Studies carried out with mainly yeast and lactic acid bacteria demonstrate the power of evolutionary engineering to deliver strains with novel phenotypes as well as insight into underlying mechanisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

Energy Technology Data Exchange (ETDEWEB)

Balch, Michael L.; Holwerda, Evert K.; Davis, Mark F.; Sykes, Robert W.; Happs, Renee M.; Kumar, Rajeev; Wyman, Charles E.; Lynd, Lee R.

2017-04-12

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 cotreatment 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.

Particle formation induced by sonication during yogurt fermentation - Impact of exopolysaccharide-producing starter cultures on physical properties.

Science.gov (United States)

Körzendörfer, Adrian; Nöbel, Stefan; Hinrichs, Jörg

2017-07-01

Two major quality defects of yogurt are syneresis and the presence of large particles, and several reasons have been extensively discussed. Vibrations during fermentation, particularly generated by pumps, must be considered as a further cause as latest research showed that both ultrasound and low frequencies induced visible particles. The aim of this study was to investigate the impact of sonication during fermentation with starter cultures differing in exopolysaccharide (EPS) synthesis on the physical properties of set (syneresis, firmness) and stirred yogurt (large particles, laser diffraction, rheology). Skim milk was fermented with starter cultures YC-471 (low EPS) or YF-L 901 (high EPS) (Chr. Hansen) and sonicated for 5min at pH5.2. Sonicated set gels exhibited syneresis and were softer than respective controls. The mechanical treatment was adjusted to quantify visible particles (d≥0.9mm) in stirred yogurts properly. Sonication significantly increased particle numbers, however, the effect was less pronounced when YF-L 901 was used, indicating EPS as a tool to reduce syneresis and particle formation due to vibrations. Rheological parameters and size of microgel particles were rather influenced by starter cultures than by sonication. Copyright © 2017 Elsevier Ltd. All rights reserved.

Electro-Fermentation - Merging Electrochemistry with Fermentation in Industrial Applications.

Science.gov (United States)

Schievano, Andrea; Pepé Sciarria, Tommy; Vanbroekhoven, Karolien; De Wever, Heleen; Puig, Sebastià; Andersen, Stephen J; Rabaey, Korneel; Pant, Deepak

2016-11-01

Electro-fermentation (EF) merges traditional industrial fermentation with electrochemistry. An imposed electrical field influences the fermentation environment and microbial metabolism in either a reductive or oxidative manner. The benefit of this approach is to produce target biochemicals with improved selectivity, increase carbon efficiency, limit the use of additives for redox balance or pH control, enhance microbial growth, or in some cases enhance product recovery. We discuss the principles of electrically driven fermentations and how EF can be used to steer both pure culture and microbiota-based fermentations. An overview is given on which advantages EF may bring to both existing and innovative industrial fermentation processes, and which doors might be opened in waste biomass utilization towards added-value biorefineries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fermentation pH influences the physiological-state dynamics of Lactobacillus bulgaricus CFL1 during pH-controlled culture.

Science.gov (United States)

Rault, Aline; Bouix, Marielle; Béal, Catherine

2009-07-01

This study aims at better understanding the effects of fermentation pH and harvesting time on Lactobacillus bulgaricus CFL1 cellular state in order to improve knowledge of the dynamics of the physiological state and to better manage starter production. The Cinac system and multiparametric flow cytometry were used to characterize and compare the progress of the physiological events that occurred during pH 6 and pH 5 controlled cultures. Acidification activity, membrane damage, enzymatic activity, cellular depolarization, intracellular pH, and pH gradient were determined and compared during growing conditions. Strong differences in the time course of viability, membrane integrity, and acidification activity were displayed between pH 6 and pH 5 cultures. As a main result, the pH 5 control during fermentation allowed the cells to maintain a more robust physiological state, with high viability and stable acidification activity throughout growth, in opposition to a viability decrease and fluctuation of activity at pH 6. This result was mainly explained by differences in lactate concentration in the culture medium and in pH gradient value. The elevated content of the ionic lactate form at high pH values damaged membrane integrity that led to a viability decrease. In contrast, the high pH gradient observed throughout pH 5 cultures was associated with an increased energetic level that helped the cells maintain their physiological state. Such results may benefit industrial starter producers and fermented-product manufacturers by allowing them to better control the quality of their starters, before freezing or before using them for food fermentation.

Ammonium carboxylate production from sugarcane trash using long-term air-lime pretreatment followed by mixed-culture fermentation.

Science.gov (United States)

Nachiappan, Balasubramaniyan; Fu, Zhihong; Holtzapple, Mark T

2011-03-01

Sugarcane trash (ST) was converted to ammonium carboxylates using a novel bioprocessing strategy known as long-term air-lime pretreatment/mixed-culture fermentation. At mild conditions (50°C, 5 weeks, 1-atm air, and excess lime loading of 0.4 g Ca(OH)(2)/(g dry biomass)), air-lime pretreatment of ST had moderate delignification (64.4%) with little loss in polysaccharides. Without employing detoxification, sterility, expensive nutrients, or costly enzymes, the feedstock (80% treated ST/20% chicken manure) was fermented to primarily ammonium acetate (>75%) and butyrate by a mixed culture of marine microorganisms at 55°C. In the best four-stage countercurrent fermentation, the product yield was 0.36 g total acids/(g VS fed) and the substrate conversion was 64%. Model predictions indicate both high acid concentrations (>47.5 g/L) and high substrate conversions (>70%) are possible at industrial scale. Copyright © 2010 Elsevier Ltd. All rights reserved.

Microbe-microbe interactions in mixed culture food fermentations

NARCIS (Netherlands)

Smid, E.J.; Lacroix, C.

2013-01-01

Most known natural and industrial food fermentation processes are driven by either simple or complex communities of microorganisms. Obviously, these fermenting microbes will not only interact with the fermentable substrate but also with each other. These microbe–microbe interactions are complex but

Quantification of viable bacterial starter cultures of Virgibacillus sp. and Tetragenococcus halophilus in fish sauce fermentation by real-time quantitative PCR.

Science.gov (United States)

Udomsil, Natteewan; Chen, Shu; Rodtong, Sureelak; Yongsawatdigul, Jirawat

2016-08-01

Real-time quantitative polymerase chain reaction (qPCR) methods were developed for the quantification of Virgibacillus sp. SK37 and Tetragenococcus halophilus MS33, which were added as starter cultures in fish sauce fermentation. The PCR assays were coupled with propidium monoazide (PMA) treatment of samples to selectively quantify viable cells and integrated with exogenous recombinant Escherichia coli cells to control variabilities in analysis procedures. The qPCR methods showed species-specificity for both Virgibacillus halodenitrificans and T. halophilus as evaluated using 6 reference strains and 28 strains of bacteria isolated from fish sauce fermentation. The qPCR efficiencies were 101.1% for V. halodenitrificans and 90.2% for T. halophilus. The quantification limits of the assays were 10(3) CFU/mL and 10(2) CFU/mL in fish sauce samples with linear correlations over 4 Logs for V. halodenitrificans and T. halophilus, respectively. The matrix effect was not observed when evaluated using fish sauce samples fermented for 1-6 months. The developed PMA-qPCR methods were successfully applied to monitor changes of Virgibacillus sp. SK37 and T. halophilus MS33 in a mackerel fish sauce fermentation model where culture-dependent techniques failed to quantify the starter cultures. The results demonstrated the usability of the methods as practical tools for monitoring the starter cultures in fish sauce fermentation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Isolation and screening of microorganisms from a gari fermentation process for starter culture development

CSIR Research Space (South Africa)

Edward, VA

2012-08-01

Full Text Available and hygienic safety of the food are vitally important for less toxic products to be obtained. Quality, safety and acceptability of traditional fermented foods may be improved through the use of starter cultures. There has been a trend recently to isolate wild...

Ziziphus mauritiana (masau) fruits fermentation in Zimbabwe: from black-box to starter culture development

NARCIS (Netherlands)

Nyanga, L.K.

2012-01-01

This thesis reports on studies of microbiological and biochemical properties of masau (Ziziphus mauritiana) fruit fermentation and the development of starter cultures for the production of masau beverages.

A survey to document the traditional processing

THE INFLUENCE OF THE COMPOSITION OF THE CULTURE MEDIUM ON THE DEVELOPMENT OF LEUCONOSTOC LACTIS PRE-FERMENTATION

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V. V. Kondratenko

2017-01-01

Full Text Available The regularity of the influence of the culture medium (substrate on the development of microflora at the stage of preliminary fermentation of the model medium on the basis of white cabbage varieties "Parus" was studied. During the research, strains of lactic acid microorganisms Leuconostoc lactis were used. Step-by-step mathematical processing of the experimental data was carried out. Functional dependencies are obtained that most adequately approximate experimental data for modified (MMC and basic (BMS model media. Analysis of the experimental data showed that, depending on the type (composition of the medium, the same species of microorganisms exhibit different dynamics of titer growth. In connection with this, an algorithm was developed to determine the optimal duration of pre-fermentation – «stop points». As a result of the research, it can be seen that the modification of the model medium with the addition of table salt and ascorbic acid to it promotes the formation of positive dynamics of the comparison indicator. This dynamics has three extremes, but only extremes are of practical significance, which were in the interval of the monotonic decrease of the titer. For successful development of the starting culture of the stage of the main fermentation, one of the conditions is a relatively small amount of the titer of the first culture at the end of the preliminary fermentation step to exclude competition. Thus, the position of the «stop-point» position corresponds to the period after the last peak of the comparison indicator. The investigated regularity of the effect of the preliminary cultivation of gram-positive microorganisms on the activity of lactic acid microorganisms in the process of fermentation is topical, since the whole process and the production of high-quality products fully depend on this approach.

Effects of oxygen limitation on sugar metabolism in yeasts: a continuous-culture study of the Kluyver effect.

Science.gov (United States)

Weusthuis, R A; Visser, W; Pronk, J T; Scheffers, W A; van Dijken, J P

1994-04-01

Growth and metabolite formation were studied in oxygen-limited chemostat cultures of Saccharomyces cerevisiae CBS 8066 and Candida utilis CBS 621 growing on glucose or maltose at a dilution rate of 0.1 h-1. With either glucose or maltose S. cerevisiae could be grown under dual limitation of oxygen and sugar. Respiration and alcoholic fermentation occurred simultaneously and the catabolite fluxes through these processes were dependent on the magnitude of the oxygen feed. C. utilis could also be grown under dual limitation of glucose and oxygen. However, at very low oxygen feed rates (i.e. below 4 mmol l-1 h-1) growth was limited by oxygen only, as indicated by the high residual glucose concentration in the culture. In contrast to S. cerevisiae, C. utilis could not be grown anaerobically at a dilution rate of 0.1 h-1. With C. utilis absence of oxygen resulted in wash-out, despite the presence of ergosterol and Tween-80 in the growth medium. The behaviour of C. utilis with respect to maltose utilization in oxygen-limited cultures was remarkable: alcoholic fermentation did not occur and the amount of maltose metabolized was dependent on the oxygen supply. Oxygen-limited cultures of C. utilis growing on maltose always contained high residual sugar concentrations. These observations throw new light on the so-called Kluyver effect. Apparently, maltose is a non-fermentable sugar for C. utilis CBS 621, despite the fact that it can serve as a substrate for growth of this facultatively fermentative yeast. This is not due to the absence of key enzymes of alcoholic fermentation. Pyruvate decarboxylase and alcohol dehydrogenase were present at high levels in maltose-utilizing cells of C. utilis grown under oxygen limitation. It is concluded that the Kluyver effect, in C. utilis growing on maltose, results from a regulatory mechanism that prevents the sugar from being fermented. Oxygen is not a key factor in this phenomenon since under oxygen limitation alcoholic fermentation of

Comparing a Dynamic Fed-Batch and a Continuous Steady-State Simulation of Ethanol Fermentation in a Distillery to a Stoichiometric Conversion Simulation

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G.C. Fonseca

Full Text Available Abstract An autonomous sugarcane bioethanol plant was simulated in EMSO software, an equation oriented process simulator. Three types of fermentation units were simulated: a six parallel fed-batch reactor system, a set of four CSTR in steady state and one consisting of a single stoichiometric reactor. Stoichiometric models are less accurate than kinetic-based fermentation models used for fed-batch and continuous fermenter simulations, since they do not account for inhibition effects and depend on a known conversion rate of reactant to be specified instead. On the other hand, stoichiometric models are faster and simpler to converge. In this study it was found that the conversion rates of sugar for the fermentation systems analyzedwere predictable from information on the composition of the juice stream. Those rates were used in the stoichiometric model, which accurately reproduced the results from both the fed-batch and the continuous fermenter system.

Shifts in metabolic hydrogen sinks in the methanogenesis-inhibited ruminal fermentation: a meta-analysis

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Emilio M. Ungerfeld

2015-02-01

Full Text Available Maximizing the flow of metabolic hydrogen ([H] in the rumen away from CH4 and towards volatile fatty acids (VFA would increase the efficiency of ruminant production and decrease its environmental impact. The objectives of this meta-analysis were: i To quantify shifts in metabolic hydrogen sinks when inhibiting ruminal methanogenesis in vitro; and ii To understand the variation in shifts of metabolic hydrogen sinks among experiments and between batch and continuous cultures systems when methanogenesis is inhibited. Batch (28 experiments, N=193 and continuous (16 experiments, N=79 culture databases of experiments with at least 50% inhibition in CH4 production were compiled. Inhibiting methanogenesis generally resulted in less fermentation and digestion in most batch culture, but not in most continuous culture, experiments. Inhibiting CH4 production in batch cultures resulted in redirection of metabolic hydrogen towards propionate and H2 but not butyrate. In continuous cultures, there was no overall metabolic hydrogen redirection towards propionate or butyrate, and H2 as a proportion of metabolic hydrogen spared from CH4 production was numerically smaller compared to batch cultures. Dihydrogen accumulation was affected by type of substrate and methanogenesis inhibitor, with highly fermentable substrates resulting in greater redirection of metabolic hydrogen towards H2 when inhibiting methanogenesis, and some oils causing small or no H2 accumulation. In both batch and continuous culture, there was a decrease in metabolic hydrogen recovered as the sum of propionate, butyrate, CH4 and H2 when inhibiting methanogenesis, and it is speculated that as CH4 production decreases metabolic hydrogen could be increasingly incorporated into formate, microbial biomass, and, perhaps, reductive acetogenesis in continuous cultures. Energetic benefits of inhibiting methanogenesis depended on the inhibitor and its concentration and on the in vitro system.

Dark fermentative hydrogen production by defined mixed microbial cultures immobilized on ligno-cellulosic waste materials

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Patel, Sanjay K.S. [Microbial Biotechnology and Genomics, Institute of Genomics and Integrative Biology (IGIB), CSIR, Delhi University Campus, Mall Road, Delhi 110007 (India); Department of Biotechnology, University of Pune, Pune 411007 (India); Purohit, Hemant J. [Environmental Genomics Unit, National Environmental Engineering Research Institute (NEERI), CSIR, Nehru Marg, Nagpur 440020 (India); Kalia, Vipin C. [Microbial Biotechnology and Genomics, Institute of Genomics and Integrative Biology (IGIB), CSIR, Delhi University Campus, Mall Road, Delhi 110007 (India)

2010-10-15

Mixed microbial cultures (MMCs) based on 11 isolates belonging to Bacillus spp. (Firmicutes), Bordetella avium, Enterobacter aerogenes and Proteus mirabilis (Proteobacteria) were employed to produce hydrogen (H{sub 2}) under dark fermentative conditions. Under daily fed culture conditions (hydraulic retention time of 2 days), MMC6 and MMC4, immobilized on ligno-cellulosic wastes - banana leaves and coconut coir evolved 300-330 mL H{sub 2}/day. Here, H{sub 2} constituted 58-62% of the total biogas evolved. It amounted to a H{sub 2} yield of 1.54-1.65 mol/mol glucose utilized over a period of 60 days of fermentation. The involvement of various Bacillus spp. -Bacillus sp., Bacillus cereus, Bacillus megaterium, Bacillus pumilus and Bacillus thuringiensis as components of the defined MMCs for H{sub 2} production has been reported here for the first time. (author)

A systems biology approach to investigate the effect of pH-induced gene regulation on solvent production by Clostridium acetobutylicum in continuous culture

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Bahl Hubert

2011-01-01

Full Text Available Abstract Background Clostridium acetobutylicum is an anaerobic bacterium which is known for its solvent-producing capabilities, namely regarding the bulk chemicals acetone and butanol, the latter being a highly efficient biofuel. For butanol production by C. acetobutylicum to be optimized and exploited on an industrial scale, the effect of pH-induced gene regulation on solvent production by C. acetobutylicum in continuous culture must be understood as fully as possible. Results We present an ordinary differential equation model combining the metabolic network governing solvent production with regulation at the genetic level of the enzymes required for this process. Parameterizing the model with experimental data from continuous culture, we demonstrate the influence of pH upon fermentation products: at high pH (pH 5.7 acids are the dominant product while at low pH (pH 4.5 this switches to solvents. Through steady-state analyses of the model we focus our investigations on how alteration in gene expression of C. acetobutylicum could be exploited to increase butanol yield in a continuous culture fermentation. Conclusions Incorporating gene regulation into the model of solvent production by C. acetobutylicum enables an accurate representation of the pH-induced switch to solvent production to be obtained and theoretical investigations of possible synthetic-biology approaches to be pursued. Steady-state analyses suggest that, to increase butanol yield, alterations in the expression of single solvent-associated genes are insufficient; a more complex approach targeting two or more genes is required.

Effect of light-dark cycles on hydrogen and poly-β-hydroxybutyrate production by a photoheterotrophic culture and Rhodobacter capsulatus using a dark fermentation effluent as substrate.

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Montiel Corona, Virginia; Le Borgne, Sylvie; Revah, Sergio; Morales, Marcia

2017-02-01

A Rhodobacter capsulatus strain and a photoheterotrophic culture (IZT) were cultivated to produce hydrogen under different light-dark cycles. A dark fermentation effluent (DFE) was used as substrate. It was found that IZT culture had an average cumulative hydrogen production (Paccum H 2 ) of 1300±43mLH 2 L -1 under continuous illumination and light-dark cycles of 30 or 60min. In contrast, R. capsulatus reduced its Paccum H 2 by 20% under 30:30min light-dark cycles, but tripled its poly-β-hydroxybutyrate (PHB) content (308±2mgPHB gdw -1 ) compared to continuous illumination. The highest PHB content by IZT culture was 178±10mgPHB gdw -1 under 15:15min light-dark cycles. PCR-DGGE analysis revealed that the IZT culture was mainly composed of Rhodopseudomonas palustris identified with high nucleotide similarity (99%). The evaluated cultures might be used for hydrogen and PHB production. They might provide energy savings by using light-dark cycles and DFE valorization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Predictive modeling in Clostridium acetobutylicum fermentations employing Raman spectroscopy and multivariate data analysis for real-time culture monitoring

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Zu, Theresah N. K.; Liu, Sanchao; Germane, Katherine L.; Servinsky, Matthew D.; Gerlach, Elliot S.; Mackie, David M.; Sund, Christian J.

2016-05-01

The coupling of optical fibers with Raman instrumentation has proven to be effective for real-time monitoring of chemical reactions and fermentations when combined with multivariate statistical data analysis. Raman spectroscopy is relatively fast, with little interference from the water peak present in fermentation media. Medical research has explored this technique for analysis of mammalian cultures for potential diagnosis of some cancers. Other organisms studied via this route include Escherichia coli, Saccharomyces cerevisiae, and some Bacillus sp., though very little work has been performed on Clostridium acetobutylicum cultures. C. acetobutylicum is a gram-positive anaerobic bacterium, which is highly sought after due to its ability to use a broad spectrum of substrates and produce useful byproducts through the well-known Acetone-Butanol-Ethanol (ABE) fermentation. In this work, real-time Raman data was acquired from C. acetobutylicum cultures grown on glucose. Samples were collected concurrently for comparative off-line product analysis. Partial-least squares (PLS) models were built both for agitated cultures and for static cultures from both datasets. Media components and metabolites monitored include glucose, butyric acid, acetic acid, and butanol. Models were cross-validated with independent datasets. Experiments with agitation were more favorable for modeling with goodness of fit (QY) values of 0.99 and goodness of prediction (Q2Y) values of 0.98. Static experiments did not model as well as agitated experiments. Raman results showed the static experiments were chaotic, especially during and shortly after manual sampling.

Development of starter culture for fermentation of millet into fura and preservation of fura by gamma radiation

International Nuclear Information System (INIS)

Amankona, Cosmos

2016-06-01

Lactic Acid Bacteria (LAB) are the most widespread of organisms responsible for food fermentation and have been applied as commercial starter cultures in many food industries. A study was conducted to develop a starter culture for the fermentation of millet into Fura and to extend the shelf life of Fura by gamma radiation. The isolation, characterization and identification of the LAB and yeasts responsible for Fura fermentation was carried out using physiological methods. A brief survey was carried out in Dome and Nima in Accra to observe and confirm the processing operations documented in literature and also obtain samples for laboratory analysis.The enumeration of aerobic mesophiles, lactic acid bacteria (LAB) and yeasts populations were carried out on Plate Count Agar, de Man Rogosa Sharpe Agar and Oxytetracycline Glucose Yeast Extract Agar respectively. The LAB species were characterized using Gram Reaction, Catalase Reaction, Oxidase Test, Salt Tolerance Test, Growth at Different Temperatures and Grow at Different pH. The LAB and yeasts Isolates were tentatively identified by determining their pattern of carbohydrate fermentation using the API 50 CH and ID 32 C galleries respectively. The LAB were also screened for their technological properties on rate of acidification, production of exopolysaccharides (EPS), amylase and protease activity including their antimicrobial activity against some common enteric pathogens using the Agar Well Diffusion Assay. Starter culture trials were carried out using dominant strains of lactic acid bacteria and yeasts in singles and in combinations. Challenge testing with Escherichia coli (RM EC. 0157; 11Q-1411), Vibrio cholerae, Staphylococcus aureus (RM SA 1L-1304), and Salmonella typhimurium (RM ST 20B-1410), in a sterile millet dough was also carried out. The lactic acid bacteria identified were Lactobacillus fermentum (33.33%), Weissella confusa (20%),Lactobacillus brevis (16.67), Pediococcus acidilactici (13

Impact of starter cultures and fermentation techniques on the volatile aroma and sensory profile of chocolate

DEFF Research Database (Denmark)

Crafack, Michael; Keul, Hanna; Eskildsen, Carl Emil Aae

2014-01-01

cultures on the formation of flavour precursors, composition of volatile aroma compounds and sensory profile was investigated in cocoa inoculated with cultures encompassing a highly aromatic strain of Pichia kluyveri or a pectinolytic strain of Kluyveromyces marxianus, and compared to commercially...... fermented heap and tray cocoa. Although only minor differences in the concentration of free amino acids and reducing sugars was measured, identification and quantification by dynamic headspace gas chromatography-mass spectrometry (HS/GC-MS) revealed pronounced differences in the composition of volatiles...... in roasted cocoa liquors and finished chocolates. 19 of the 56 volatile compounds identified in the chocolates were found in significantly higher amounts in the tray fermented sample, whilst significantly higher amounts of 2-methoxyphenol was measured in the two inoculated chocolates. The P. kluyveri...

Bioethanol production from sweet potato (Ipomoea batatas L. flour using co-culture of Trichoderma sp. and Saccharomyces cerevisiae in solid-state fermentation

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Manas Ranjan Swain

2013-04-01

Full Text Available The aim of this work was to study the optimiation of co-culturing of Trichoderma sp. and Saccharomyces cerevisiae (1:4 ratio on sweet potato (Ipomoea batatas L. flour (SPF for the production of bio-ethanol in solid-state fermentation (SSF. Maximum ethanol (172 g/kg substrate was produced in a medium containing 80% moisture, ammonium sulphate 0.2%, pH 5.0, inoculuted with 10% inoculum size and fermented at 30ºC for 72h. .Concomitant with highest ethanol concentration, maximum ethanol productivity (2.8 g/kg substrate/h, microbial biomass (23×10(8 CFU/ g substrate, ethanol yield (47 g/100g sugar consumed and fermentation efficiency (72% were also obtained under these conditions. Cell interaction was observed familiar between the viable cells of Trichoderma sp. and S. cerevisiae when co-cultured. Ethanol production ability by the co-culture was 65 % higher than the single culture of S. cerevisiae from un-saccharified SPF.

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

Energy Technology Data Exchange (ETDEWEB)

Kaufman, E. N.; Cooper, S. P.; Clement, S. L.; Little, M. H.

1994-05-01

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 the 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.

Volatile Organic Compounds in Naturally Fermented Milk and Milk Fermented Using Yeasts, Lactic Acid Bacteria and Their Combinations As Starter Cultures

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Bennie C. Viljoen

2007-01-01

Full Text Available The volatile organic compounds present in 18 Zimbabwean naturally fermented milk (amasi samples and those produced by various yeasts, lactic acid bacteria (LAB and yeast/ LAB combinations were determined using headspace gas chromatography. The yeast strains used were: Candida kefyr 23, C. lipolytica 57, Saccharomyces cerevisiae 71, C. lusitaniae 68, C. tropicalis 78, C. lusitaniae 63, C. colliculosa 41, S. dairenensis 32, and Dekkera bruxellensis 43, and were coded Y1 to Y9, respectively. The LAB strains used were Lactococcus lactis subsp. lactis Lc39, L. lactis subsp. lactis Lc261, Lactobacillus paracasei Lb11, and L. lactis subsp. lactis biovar. diacetylactis C1, and were coded B1 to B4, respectively. Some of the volatile organic compounds found in amasi were acetaldehyde, ethanol, acetone, 2-methyl propanal, 2-methyl-1-propanol and 3-methyl-1-butanol. However, the levels of volatile organic compounds in the naturally fermented milk (NFM samples varied from one sample to another, with acetaldehyde ranging from 0.1–18.4 ppm, 3-methyl butanal from <0.1–0.47 ppm and ethanol from 39.3–656 ppm. The LAB/C. kefyr 23 (B/Y1 co-cultures produced significantly (p<0.05 higher levels of acetaldehyde and ethanol than the levels found in the NFM. The acetaldehyde levels in the B/Y1 samples ranged from 26.7–87.7 ppm, with L. lactis subsp. lactis biovar. diacetylactis C1 (B4 producing the highest level of acetaldehyde in combination with C. kefyr 23 (Y1. Using principal component analysis (PCA, most of the NFM samples were grouped together with single and co-cultures of Lc261, Lb11 and the non-lactose fermenting yeasts, mainly because of the low levels of ethanol and similar levels of 3-methyl butanal. Chromatograms of amasi showed prominent peak of methyl aldehydes and their alcohols including 3-methyl-butanal and 3-methyl-butanol, suggesting that these compounds are important attributes of Zimbabwean naturally fermented milk.

Ethnobotany of wild plants used for starting fermented beverages in Shui communities of southwest China.

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Hong, Liya; Zhuo, Jingxian; Lei, Qiyi; Zhou, Jiangju; Ahmed, Selena; Wang, Chaoying; Long, Yuxiao; Li, Feifei; Long, Chunlin

2015-05-28

Shui communities of southwest China have an extensive history of using wild plants as starters (Xiaoqu) to prepare fermented beverages that serve important roles in interpersonal relationships and cultural events. While the practice of using wild plants as starters for the preparation of fermented beverages was once prevalent throughout China, this tradition has seen a decline nationally since the 1930s. The traditional technique of preparing fermented beverages from wild plant starters remains well preserved in the Shui communities in southwest China and provides insight on local human-environment interactions and conservation of plant biodiversity for cultural purposes. The present study sought to examine the ethnobotany of wild plants used as starters for the preparation of fermented beverages including an inventory of plants used as a starter in liquor fermentation and associated knowledge and practices. Field surveys were carried out that consisted of semi-structured surveys and plant species inventories. One hundred forty-nine informants in twenty Shui villages were interviewed between July 2012 and October 2014 to document knowledge associated with wild plants used as a liquor fermentation starter. The inventories involved plant voucher specimens and taxonomic identification of plant collections. A total of 103 species in 57 botanical families of wild plants were inventoried and documented that are traditionally used as starters for preparing fermented beverages by Shui communities. The majority of the species (93.2%) have multiple uses in addition to being used as a starter with medicinal purposes being the most prevalent. Shui women are the major harvesters and users of wild plants used as starters for preparing fermented beverages and transfer knowledge orally from mother to daughter. Findings from this study can serve as a basis for future investigation on fermented beverages and foods and associated knowledge and cultural practices. However, with rapid

Microbiological and Physicochemical Characterization of Small-Scale Cocoa Fermentations and Screening of Yeast and Bacterial Strains To Develop a Defined Starter Culture

Science.gov (United States)

Pereira, Gilberto Vinícius de Melo; Miguel, Maria Gabriela da Cruz Pedrozo; Ramos, Cíntia Lacerda

2012-01-01

Spontaneous cocoa bean fermentations performed under bench- and pilot-scale conditions were studied using an integrated microbiological approach with culture-dependent and culture-independent techniques, as well as analyses of target metabolites from both cocoa pulp and cotyledons. Both fermentation ecosystems reached equilibrium through a two-phase process, starting with the simultaneous growth of the yeasts (with Saccharomyces cerevisiae as the dominant species) and lactic acid bacteria (LAB) (Lactobacillus fermentum and Lactobacillus plantarum were the dominant species), which were gradually replaced by the acetic acid bacteria (AAB) (Acetobacter tropicalis was the dominant species). In both processes, a sequence of substrate consumption (sucrose, glucose, fructose, and citric acid) and metabolite production kinetics (ethanol, lactic acid, and acetic acid) similar to that of previous, larger-scale fermentation experiments was observed. The technological potential of yeast, LAB, and AAB isolates was evaluated using a polyphasic study that included the measurement of stress-tolerant growth and fermentation kinetic parameters in cocoa pulp media. Overall, strains L. fermentum UFLA CHBE8.12 (citric acid fermenting, lactic acid producing, and tolerant to heat, acid, lactic acid, and ethanol), S. cerevisiae UFLA CHYC7.04 (ethanol producing and tolerant to acid, heat, and ethanol), and Acetobacter tropicalis UFLA CHBE16.01 (ethanol and lactic acid oxidizing, acetic acid producing, and tolerant to acid, heat, acetic acid, and ethanol) were selected to form a cocktail starter culture that should lead to better-controlled and more-reliable cocoa bean fermentation processes. PMID:22636007

Secondary products and consumption of sugar during continuous alcoholic fermentation of starchy media

Energy Technology Data Exchange (ETDEWEB)

Nakhmanovich, B M; Yarovenko, V L; Makeev, D M; Belov, E M

1976-01-01

Continuous alcohol fermentation in different media containing starch as the carbon source and final analysis of products indicated that 93.3% glucose is converted into ethanol and CO/sub 2/, 2.78% metabolized by the yeast cells, 2.4% converted into glycerol, 0.036% into acetic acid, 0.25% into lactic acid, and a nonsignificant percentage was changed into other organic acids and higher alcohols.

Hydrogen production characteristics of the organic fraction of municipal solid wastes by anaerobic mixed culture fermentation

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Dong, Li; Yu, Zhang [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China)]|[Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Zhenhong, Yuan; Yongming, Sun; Xiaoying, Kong [Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640 (China)

2009-01-15

The hydrogen production from the organic fraction of municipal solid waste (OFMSW) by anaerobic mixed culture fermentation was investigated using batch experiments at 37 C. Seven varieties of typical individual components of OFMSW including rice, potato, lettuce, lean meat, oil, fat and banyan leaves were selected to estimate the hydrogen production potential. Experimental results showed that the boiling treated anaerobic sludge was effective mixed inoculum for fermentative hydrogen production from OFMSW. Mechanism of fermentative hydrogen production indicates that, among the OFMSW, carbohydrates is the most optimal substrate for fermentative hydrogen production compared with proteins, lipids and lignocelluloses. This conclusion was also substantiated by experimental results of this study. The hydrogen production potentials of rice, potato and lettuce were 134 mL/g-VS, 106 mL/g-VS, and 50 mL/g-VS respectively. The hydrogen percentages of the total gas produced from rice, potato and lettuce were 57-70%, 41-55% and 37-67%. (author)

Acid protease and formation of multiple forms of glucoamylase in batch and continuous cultures of Aspergillus niger

DEFF Research Database (Denmark)

Aalbæk, Thomas; Reeslev, Morten; Jensen, Bo

2002-01-01

with molecular weights of approx. 91 (GAI), 73 (GAII), and 59 kDa (GAIII). Data from batch fermentations with constant pH 3.0 and 5.0 showed a uniform distribution of extracellular GA forms throughout the fermentations and independent of culture growth phases. Furthermore, steady-state data from chemostat...

Impact of zinc supplementation on the improvement of ethanol tolerance and yield of self-flocculating yeast in continuous ethanol fermentation.

Science.gov (United States)

Zhao, X Q; Xue, C; Ge, X M; Yuan, W J; Wang, J Y; Bai, F W

2009-01-01

The effects of zinc supplementation were investigated in the continuous ethanol fermentation using self-flocculating yeast. Zinc sulfate was added at the concentrations of 0.01, 0.05 and 0.1 g l(-1), respectively. Reduced average floc sizes were observed in all the zinc-supplemented cultures. Both the ethanol tolerance and thermal tolerance were significantly improved by zinc supplements, which correlated well with the increased ergosterol and trehalose contents in the yeast flocs. The highest ethanol concentration by 0.05 g l(-1) zinc sulfate supplementation attained 114.5 g l(-1), in contrast to 104.1 g l(-1) in the control culture. Glycerol production was decreased by zinc supplementations, with the lowest level 3.21 g l(-1), about 58% of the control. Zinc content in yeast cells was about 1.4 microMol g(-1) dry cell weight, about sixfold higher than that of control in all the zinc-supplemented cultures, and close correlation of zinc content in yeast cells with the cell viability against ethanol and heat shock treatment was observed. These studies suggest that exogenous zinc addition led to a reprogramming of cellular metabolic network, resulting in enhanced ethanol tolerance and ethanol production.

Yeast diversity during the fermentation of Andean chicha: A comparison of high-throughput sequencing and culture-dependent approaches.

Science.gov (United States)

Mendoza, Lucía M; Neef, Alexander; Vignolo, Graciela; Belloch, Carmela

2017-10-01

Diversity and dynamics of yeasts associated with the fermentation of Argentinian maize-based beverage chicha was investigated. Samples taken at different stages from two chicha productions were analyzed by culture-dependent and culture-independent methods. Five hundred and ninety six yeasts were isolated by classical microbiological methods and 16 species identified by RFLPs and sequencing of D1/D2 26S rRNA gene. Genetic typing of isolates from the dominant species, Saccharomyces cerevisiae, by PCR of delta elements revealed up to 42 different patterns. High-throughput sequencing (HTS) of D1/D2 26S rRNA gene amplicons from chicha samples detected more than one hundred yeast species and almost fifty filamentous fungi taxa. Analysis of the data revealed that yeasts dominated the fermentation, although, a significant percentage of filamentous fungi appeared in the first step of the process. Statistical analysis of results showed that very few taxa were represented by more than 1% of the reads per sample at any step of the process. S. cerevisiae represented more than 90% of the reads in the fermentative samples. Other yeast species dominated the pre-fermentative steps and abounded in fermented samples when S. cerevisiae was in percentages below 90%. Most yeasts species detected by pyrosequencing were not recovered by cultivation. In contrast, the cultivation-based methodology detected very few yeast taxa, and most of them corresponded with very few reads in the pyrosequencing analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cane molasses fermentation for continuous ethanol production in an immobilized cells reactor by Saccharomyces cerevisiae

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Ghorbani, Farshid; Younesi, Habibollah; Esmaeili Sari, Abbas [Department of Environmental Science, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, Noor, P.O. Box: 64414-356 (Iran); Najafpour, Ghasem [Department of Chemical Engineering, Faculty of Engineering, Noshirvani University of Technology, Babol (Iran)

2011-02-15

Sodium-alginate immobilized yeast was employed to produce ethanol continuously using cane molasses as a carbon source in an immobilized cell reactor (ICR). The immobilization of Saccharomyces cerevisiae was performed by entrapment of the cell cultured media harvested at exponential growth phase (16 h) with 3% sodium alginate. During the initial stage of operation, the ICR was loaded with fresh beads of mean diameter of 5.01 mm. The ethanol production was affected by the concentration of the cane molasses (50, 100 and 150 g/l), dilution rates (0.064, 0.096, 0.144 and 0.192 h{sup -1}) and hydraulic retention time (5.21, 6.94, 10.42 and 15.63 h) of the media. The pH of the feed medium was set at 4.5 and the fermentation was carried out at an ambient temperature. The maximum ethanol production, theoretical yield (Y{sub E/S}), volumetric ethanol productivity (Q{sub P}) and total sugar consumption was 19.15 g/l, 46.23%, 2.39 g l{sup -1} h{sup -1} and 96%, respectively. (author)

Preparation of a Lactobacillus plantarum starter culture for cucumber fermentations that can meet kosher guidelines

Science.gov (United States)

A method is described for growth of a Lactobacillus plantarum starter culture in jars of commercially available pasteurized fresh-pack kosher dill cucumbers so that jars can be used to inoculate commercial scale cucumber fermentation tanks. A procedure is also described to transfer lactic acid bacte...

Characterization of lactic acid bacteria isolated from infant faeces as potential probiotic starter cultures for fermented sausages.

Science.gov (United States)

Rubio, Raquel; Jofré, Anna; Martín, Belén; Aymerich, Teresa; Garriga, Margarita

2014-04-01

A total of 109 lactic acid bacteria isolated from infant faeces were identified by partial 16S rRNA, cpn60 and/or pheS sequencing. Lactobacillus was the most prevalent genus, representing 48% of the isolates followed by Enterococcus (38%). Lactobacillus gasseri (21%) and Enterococcus faecalis (38%) were the main species detected. A further selection of potential probiotic starter cultures for fermented sausages focused on Lactobacillus as the most technologically relevant genus in this type of product. Lactobacilli strains were evaluated for their ability to grow in vitro in the processing conditions of fermented sausages and for their functional and safety properties, including antagonistic activity against foodborne pathogens, survival from gastrointestinal tract conditions (acidity, bile and pancreatin), tyramine production, antibiotic susceptibility and aggregation capacity. The best strains according to the results obtained were Lactobacillus casei/paracasei CTC1677, L. casei/paracasei CTC1678, Lactobacillus rhamnosus CTC1679, L. gasseri CTC1700, L. gasseri CTC1704, Lactobacillus fermentum CTC1693. Those strains were further assayed as starter cultures in model sausages. L. casei/paracasei CTC1677, L. casei/paracasei CTC1678 and L. rhamnosus CTC1679 were able to lead the fermentation and dominate (levels ca. 10(8) CFU/g) the endogenous lactic acid bacteria, confirming their suitability as probiotic starter cultures. Copyright © 2013 Elsevier Ltd. All rights reserved.

Adaptive control of biomass and substrate concentration in a continuous-flow. Fermentation process

Energy Technology Data Exchange (ETDEWEB)

Chamilothoris, G; Sevely, Y; Sevely, Y

1988-01-01

This paper presents a simple adaptive control scheme for the simultaneous regulation of biomass and substrate concentration in a continuous fermentation process. The proposed algorithm includes the on-line estimation of a time-varying parameter (namely the specific growth rate) and two cascaded regulators of self-tuning inspiration. Convergence of the control algorithm, in the BIBO sense, is theoretically established and its effectiveness is illustrated by simulation examples.

Optimization and control of a continuous stirred tank fermenter using learning system

Energy Technology Data Exchange (ETDEWEB)

Thibault, J [Dept. of Chemical Engineering, Laval Univ., Quebec City, PQ (Canada); Najim, K [CNRS, URA 192, GRECO SARTA, Ecole Nationale Superieure d' Ingenieurs de Genie Chimique, 31 - Toulouse (France)

1993-05-01

A variable structure learning automaton is used as an optimization and control of a continuous stirred tank fermenter. The alogrithm requires no modelling of the process. The use of appropriate learning rules enables to locate the optimum dilution rate in order to maximize an objective cost function. It is shown that a hierarchical structure of automata can adapt to environmental changes and can also modify efficiently the domain of variation of the control variable in order to encompass the optimum value. (orig.)

Fermentation of glycolate by a pure culture of a strictly anaerobic gram-positive bacterium belonging to the family Lachnospiraceae.

Science.gov (United States)

Janssen, Peter H; Hugenholtz, Philip

2003-05-01

The component bacteria of a three-membered mixed culture able to ferment glycolate to acetate, propionate and CO(2) were isolated in pure culture. All three strains were strict anaerobes that, on the basis of comparative 16S rRNA gene sequence analysis, belonged to the order Clostridiales in the phylum Firmicutes (low G+C gram-positive bacteria). Two of the strains were not involved in glycolate metabolism. The third, the glycolate-fermenting strain 19gly4 (DSM 11261), was related to members of the family Lachnospiraceae. The cells of strain 19gly4 were oval- to lemon-shaped, 0.85 microm long and 0.65 microm in diameter, occurring singly, in pairs, or in chains of up to 30 cells. Strain 19gly4 fermented glycolate or fumarate to acetate, succinate, and CO(2). Hydrogen was not formed, and strain 19gly4 was able to grow on glycolate in pure culture without any syntrophic hydrogen transfer and without the use of an external electron acceptor. There was no evidence for homoacetogenic metabolism. This bacterium therefore differs in metabolism from previously reported glycolate-utilising anaerobes.

Microbial culture selection for bio-hydrogen production from waste ground wheat by dark fermentation

Energy Technology Data Exchange (ETDEWEB)

Argun, Hidayet; Kargi, Fikret; Kapdan, Ilgi K. [Department of Environmental Engineering, Dokuz Eylul University, Buca, Izmir (Turkey)

2009-03-15

Hydrogen formation performances of different anaerobic bacteria were investigated in batch dark fermentation of waste wheat powder solution (WPS). Serum bottles containing wheat powder were inoculated with pure cultures of Clostridium acetobutylicum (CAB), Clostridium butyricum (CB), Enterobacter aerogenes (EA), heat-treated anaerobic sludge (ANS) and a mixture of those cultures (MIX). Cumulative hydrogen formation (CHF), hydrogen yield (HY) and specific hydrogen production rate (SHPR) were determined for every culture. The heat-treated anaerobic sludge was found to be the most effective culture with a cumulative hydrogen formation of 560 ml, hydrogen yield of 223 ml H{sub 2} g{sup -1} starch and a specific hydrogen production rate of 32.1 ml H{sub 2} g{sup -1} h{sup -1}. (author)

Development of High-Productivity Continuous Ethanol Production using PVA-Immobilized Zymomonas mobilis in an Immobilized-Cells Fermenter

Directory of Open Access Journals (Sweden)

Nurhayati Nurhayati

2015-07-01

Full Text Available Ethanol as one of renewable energy was being considered an excellent alternative clean-burning fuel to replace gasoline. Continuous ethanol fermentation systems had offered important economic advantages compared to traditional systems. Fermentation rates were significantly improved, especially when continuous fermentation was integrated with cell immobilization techniques to enrich the cells concentration in fermentor. Growing cells of Zymomonas mobilis immobilized in polyvinyl alcohol (PVA gel beads were employed in an immobilized-cells fermentor for continuous ethanol fermentation from glucose. The glucose loading, dilution rate, and cells loading were varied in order to determine which best condition employed in obtaining both high ethanol production and low residual glucose with high dilution rate. In this study, 20 g/L, 100 g/L, 125 g/L and 150 g/L of glucose concentration and 20% (w/v, 40% (w/v and 50% (w/v of cells loading were employed with range of dilution rate at 0.25 to 1 h-1. The most stable production was obtained for 25 days by employing 100 g/L of glucose loading. Meanwhile, the results also exhibited that 125 g/L of glucose loading as well as 40% (w/v of cells loading yielded high ethanol concentration, high ethanol productivity, and acceptable residual glucose at 62.97 g/L, 15.74 g/L/h and 0.16 g/L, respectively. Furthermore, the dilution rate of 4 hour with 100 g/L and 40% (w/v of glucose and cells loading was considered as the optimum condition with ethanol production, ethanol productivity and residual glucose obtained were 49.89 g/L, 12.47 g/L/h, and 2.04 g/L, respectively. This recent study investigated ethanol inhibition as well. The present research had proved that high sugar concentration was successfully converted to ethanol. These achieved results were promising for further study.

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

Science.gov (United States)

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

When national culture is disrupted : Cultural continuity and resistance to Muslim immigrants

NARCIS (Netherlands)

Smeekes, Anouk; Verkuijten, Maykel

In three studies we examined the importance of cultural continuity for attitudes towards Muslim immigrants. Study 1 showed that perceiving national culture to be temporally enduring predicted opposition to Muslim expressive rights, and this effect was mediated by perceptions of continuity threat.

Biodegradation of Palm Kernel Cake by Cellulolytic and Hemicellulolytic Bacterial Cultures through Solid State Fermentation

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Mohamed Idris Alshelmani

2014-01-01

Full Text Available Four cellulolytic and hemicellulolytic bacterial cultures were purchased from the Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Culture (DSMZ and the American Type Culture Collection (ATCC. Two experiments were conducted; the objective of the first experiment was to determine the optimum time period required for solid state fermentation (SSF of palm kernel cake (PKC, whereas the objective of the second experiment was to investigate the effect of combinations of these cellulolytic and hemicellulolytic bacteria on the nutritive quality of the PKC. In the first experiment, the SSF was lasted for 12 days with inoculum size of 10% (v/w on different PKC to moisture ratios. In the second experiment, fifteen combinations were created among the four microbes with one untreated PKC as a control. The SSF lasted for 9 days, and the samples were autoclaved, dried, and analyzed for proximate analysis. Results showed that bacterial cultures produced high enzymes activities at the 4th day of SSF, whereas their abilities to produce enzymes tended to be decreased to reach zero at the 8th day of SSF. Findings in the second experiment showed that hemicellulose and cellulose was significantly P<0.05 decreased, whereas the amount of reducing sugars were significantly P<0.05 increased in the fermented PKC (FPKC compared with untreated PKC.

Comparing a Dynamic Fed-Batch and a Continuous Steady-State Simulation of Ethanol Fermentation in a Distillery to a Stoichiometric Conversion Simulation

OpenAIRE

Fonseca, G.C.; Costa, C.B.B.; Cruz, A.J.G.

2017-01-01

Abstract An autonomous sugarcane bioethanol plant was simulated in EMSO software, an equation oriented process simulator. Three types of fermentation units were simulated: a six parallel fed-batch reactor system, a set of four CSTR in steady state and one consisting of a single stoichiometric reactor. Stoichiometric models are less accurate than kinetic-based fermentation models used for fed-batch and continuous fermenter simulations, since they do not account for inhibition effects and depen...

Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate‐reducing benthic microbial populations

Science.gov (United States)

Saad, Sainab; Bhatnagar, Srijak; Tegetmeyer, Halina E.; Geelhoed, Jeanine S.; Strous, Marc

2017-01-01

Summary For the anaerobic remineralization of organic matter in marine sediments, sulfate reduction coupled to fermentation plays a key role. Here, we enriched sulfate‐reducing/fermentative communities from intertidal sediments under defined conditions in continuous culture. We transiently exposed the cultures to oxygen or nitrate twice daily and investigated the community response. Chemical measurements, provisional genomes and transcriptomic profiles revealed trophic networks of microbial populations. Sulfate reducers coexisted with facultative nitrate reducers or aerobes enabling the community to adjust to nitrate or oxygen pulses. Exposure to oxygen and nitrate impacted the community structure, but did not suppress fermentation or sulfate reduction as community functions, highlighting their stability under dynamic conditions. The most abundant sulfate reducer in all cultures, related to Desulfotignum balticum, appeared to have coupled both acetate‐ and hydrogen oxidation to sulfate reduction. We describe a novel representative of the widespread uncultured candidate phylum Fermentibacteria (formerly candidate division Hyd24‐12). For this strictly anaerobic, obligate fermentative bacterium, we propose the name ‘USabulitectum silens’ and identify it as a partner of sulfate reducers in marine sediments. Overall, we provide insights into the function of fermentative, as well as sulfate‐reducing microbial communities and their adaptation to a dynamic environment. PMID:28836729

[Fermentation behaviors of recombinant Pichia pastoris under inhibited methanol concentration].

Science.gov (United States)

Zhou, Xiang-Shan; Fan, Wei-Min; Zhang, Yuan-Xing

2003-09-01

Chemostat culture was performed to characterize the growth, substrate consumption and the hirudin production, and to disclose their interrelations in the fermentation of recombinant Pichia pastoris. The Andrew substrate-inhibited growth model is more suitable than Monod model to simulate the growth of Pichia pastoris on methanol. Therefore, two stationary states can be obtained in the continuous culture at a certain dilution rate because of the substrate inhibition on cell growth. The stationary state could be obtained if only the dilution rate not more than 0.048 h(-1) in the continuous fermentation. The concentrations of cell, methanol and hirudin were constant after 50 h continuous culture with dilution rate at 0.04 h(-1). However, it could not be obtained when the dilution rate more than 0.048 h(-1) because the other stationary point at S > 0.048 h(-1) is unstable. Therefore, it was found that the cell concentration declined and the methanol concentration increased from 2.9 g/L to 18.1 g/L within 18h at dilution rate 0.06 h(-1). Thus, the fed-batch culture with a constant specific growth rate was carried out to disclose the fermentation behavior at high and constant methanol concentration in aid of a methanol sensor. The theoretical maximum specific growth rate, microm = 0.0464 h(-1), was found under critical methanol concentration, Scrit = 3.1 g/L. The growth of P. pastoris was typically methanol-limited at the methanol concentration S Scrit. The maximum specific Hir65 production rate qp was obtained at 0.2 mg/(g x h) when methanol concentration and mu were 0.5 g/L and 0.02 h(-1), respectively. The specific Hir65 production rate qp increased with the increase of mu and S at mu 0.02 h(-1). The specific methanol consumption rate increased with the increase of S when S 5 g/L. At last, the high Hir65 production rate 0.2 mg/(g x h) was obtained in the fermentation conducted under methanol-limited concentration and mu controlled at 0.5 g/L and 0.02 h(-1

The microbial diversity of traditional spontaneously fermented lambic beer

OpenAIRE

Spitaels, Freek; Wieme, Anneleen D.; Janssens, Maarten; Aerts, Maarten; Daniel, Heide-Marie; Van Landschoot, Anita; De Vuyst, Luc; Vandamme, Peter

2014-01-01

Lambic sour beers are the products of a spontaneous fermentation that lasts for one to three years before bottling. The present study determined the microbiota involved in the fermentation of lambic beers by sampling two fermentation batches during two years in the most traditional lambic brewery of Belgium, using culture-dependent and culture-independent methods. From 14 samples per fermentation, over 2000 bacterial and yeast isolates were obtained and identified. Although minor variations i...

In Search of functionality-diversity relationships in anaerobic mixed culture fermentations

International Nuclear Information System (INIS)

Kleerebezem, R.; Temudo, M.; Muyzer Van Loosdrecht, M. C. M.

2009-01-01

Based on the work described in this paper we will postulate that in environmental ecosystems with a weak selective pressure no clear relationship exists between the ecosystem functionality and the microbial diversity and microbial composition. In the past years we have been investigating the anaerobic fermentation of glucose, xylose, and glycerol, and mixtures of these substrates in continuously stirred tank reactors (CSTR) inoculated with an activated sludge characterized by a very rich microbial diversity. (Author)

Lactic Acid Bacterial Starter Culture with Antioxidant and γ-Aminobutyric Acid Biosynthetic Activities Isolated from Flatfish-Sikhae Fermentation.

Science.gov (United States)

Won, Yeong Geol; Yu, Hyun-Hee; Chang, Young-Hyo; Hwang, Han-Joon

2015-12-01

The aim of this study is to select a lactic acid bacterial strain as a starter culture for flatfish-Sikhae fermentation and to evaluate its suitability for application in a food system. Four strains of lactic acid bacteria isolated from commercial flatfish-Sikhae were identified and selected as starter culture candidates through investigation of growth rates, salt tolerance, food safety, and functional properties such as antioxidative and antimicrobial activities. The fermentation properties of the starter candidates were also examined in food systems prepared with these strains (candidate batch) in comparison with a spontaneous fermentation process without starter culture (control batch) at 15°C. The results showed that the candidate YG331 batch had better fermentation properties such as viable cell count, pH, and acidity than the other experimental batches, including the control batch. The results are expressed according to selection criteria based on a preliminary sensory evaluation and physiochemical investigation. Also, only a small amount of histamine was detected with the candidate YG331 batch. The radical scavenging activity of the candidate batches was better compared with the control batch, and especially candidate YG331 batch showed the best radical scavenging activity. Also, we isolated another starter candidate (identified as Lactobacillus brevis PM03) with γ-aminobutyric acid (GABA)-producing activity from commercial flatfish-Sikhae products. The sensory scores of the candidate YG331 batch were better than those of the other experimental batches in terms of flavor, color, and overall acceptance. In this study, we established selection criteria for the lactic acid bacterial starter for the flatfish-Sikhae production and finally selected candidate YG331 as the most suitable starter.

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

Science.gov (United States)

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.

Simultaneous Saccharification and Fermentation of Sugar Beet Pulp with Mixed Bacterial Cultures for Lactic Acid and Propylene Glycol Production

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Joanna Berlowska

2016-10-01

Full Text Available Research into fermentative production of lactic acid from agricultural by-products has recently concentrated on the direct conversion of biomass, whereby pure sugars are replaced with inexpensive feedstock in the process of lactic acid production. In our studies, for the first time, the source of carbon used is sugar beet pulp, generated as a by-product of industrial sugar production. In this paper, we focus on the simultaneous saccharification of lignocellulosic biomass and fermentation of lactic acid, using mixed cultures with complementary assimilation profiles. Lactic acid is one of the primary platform chemicals, and can be used to synthesize a wide variety of useful products, including green propylene glycol. A series of controlled batch fermentations was conducted under various conditions, including pretreatment with enzymatic hydrolysis. Inoculation was performed in two sequential stages, to avoid carbon catabolite repression. Biologically-synthesized lactic acid was catalytically reduced to propylene glycol over 5% Ru/C. The highest lactic acid yield was obtained with mixed cultures. The yield of propylene glycol from the biological lactic acid was similar to that obtained with a water solution of pure lactic acid. Our results show that simultaneous saccharification and fermentation enables generation of lactic acid, suitable for further chemical transformations, from agricultural residues.

Looking for practical tools to achieve next-future applicability of dark fermentation to produce bio-hydrogen from organic materials in Continuously Stirred Tank Reactors.

Science.gov (United States)

Tenca, A; Schievano, A; Lonati, S; Malagutti, L; Oberti, R; Adani, F

2011-09-01

This study aimed at finding applicable tools for favouring dark fermentation application in full-scale biogas plants in the next future. Firstly, the focus was obtaining mixed microbial cultures from natural sources (soil-inocula and anaerobically digested materials), able to efficiently produce bio-hydrogen by dark fermentation. Batch reactors with proper substrate (1 gL(glucose)(-1)) and metabolites concentrations, allowed high H(2) yields (2.8 ± 0.66 mol H(2)mol(glucose)(-1)), comparable to pure microbial cultures achievements. The application of this methodology to four organic substrates, of possible interest for full-scale plants, showed promising and repeatable bio-H(2) potential (BHP=202 ± 3 NL(H2)kg(VS)(-1)) from organic fraction of municipal source-separated waste (OFMSW). Nevertheless, the fermentation in a lab-scale CSTR (nowadays the most diffused typology of biogas-plant) of a concentrated organic mixture of OFMSW (126 g(TS)L(-1)) resulted in only 30% of its BHP, showing that further improvements are still needed for future full-scale applications of dark fermentation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Benzoic Acid Production with Respect to Starter Culture and Incubation Temperature during Yogurt Fermentation using Response Surface Methodology.

Science.gov (United States)

Yu, Hyung-Seok; Lee, Na-Kyoung; Jeon, Hye-Lin; Eom, Su Jin; Yoo, Mi-Young; Lim, Sang-Dong; Paik, Hyun-Dong

2016-01-01

Benzoic acid is occasionally used as a raw material supplement in food products and is sometimes generated during the fermentation process. In this study, the production of naturally occurring yogurt preservatives was investigated for various starter cultures and incubation temperatures, and considered food regulations. Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus reuteri, Lactobacillus plantarum, Bifidobacterium longum, Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium infantis, and Bifidobacterium breve were used as yogurt starter cultures in commercial starters. Among these strains, L. rhamnosus and L. paracasei showed the highest production of benzoic acid. Therefore, the use of L. rhamnosus, L. paracasei, S. thermophilus, and different incubation temperatures were examined to optimize benzoic acid production. Response surface methodology (RSM) based on a central composite design was performed for various incubation temperatures (35-44℃) and starter culture inoculum ratios (0-0.04%) in a commercial range of dairy fermentation processes. The optimum conditions were 0.04% L. rhamnosus, 0.01% L. paracasei, 0.02% S. thermophilus, and 38.12℃, and the predicted and estimated concentrations of benzoic acid were 13.31 and 13.94 mg/kg, respectively. These conditions maximized naturally occurring benzoic acid production during the yogurt fermentation process, and the observed production levels satisfied regulatory guidelines for benzoic acid in dairy products.

Accelerated fermentation of cheese whey. Developing the system

Energy Technology Data Exchange (ETDEWEB)

Bechtle, R M; Claydon, T J

1971-01-01

A system for accelerated fermentation of cheese wheys requires a mixed yeast and lactose-fermenting bacterial culture. The air flow required (110 ml/min/1./1% of lactose) was proportional to the concentration of wheys in the media. Yeast cell-mass production by accelerated fermentation was equal to or greater than the whey concentration factor when compared with yeast production of single yeast strain production on unconcentrated wheys. Generally, on triple strength wheys, yeast production was approximately 1 lb/gallon of medium. Fermentation media formulas were developed with whey analysis, shake culture, and fermentor trials. The formula used with a specific whey must be adequate to supplement the mineral deficiencies in the whey and to provide trace elements and nutrients essential for maximum microbial growth. High-rate aeration was required for both respiration of the microbial culture and to purge the ferment of volatile metabolites, whose presence depressed microbial cell synthesis.

Flavour profiles of dry sausages fermented by selected novel meat starter cultures.

Science.gov (United States)

Erkkilä, S; Petäjä, E; Eerola, S; Lilleberg, L; Mattila-Sandholm, T; Suihko, M L

2001-06-01

Probiotic or bioprotective Lactobacillus rhamnosus strains GG, LC-705 and E-97800 as well as Pediococcus pentosaceus E-90390 and Lactobacillus plantarum E-98098 were studied for their ability to act as main fermenting organisms in the manufacturing process of dry sausages. In the preliminary tests, their abilities to produce lactic acid and biogenic amines, histamine or tyramine, were studied in MRS broth and analysed by high-performance liquid chromatography. The strains produced higher or equal amounts of lactic acid compared to control and were amine negative. During the actual fermentation process of dry sausages the numbers of inoculated bacteria increased from the level 6.5-7.0 log cfu/g to 8.0-9.0 log cfu/g. The most fast growing strains were P. pentosaceus E-90390 and the control while the growth of L. plantarum E-98098 and L. rhamnosus LC-705 were the slowest. The pH value of the sausages decreased from 5.6 to 4.9-5.0. The presence of these experimental strains as major organisms in the sausages after fermentation and ripening was confirmed on the bases of their genetic fingerprints. The flavour profiles of the experimental sausages produced by these probiotic or protective strains were similar with that produced by the commercial meat starter culture and commercial North European dry sausage recipe.

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

Science.gov (United States)

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.

A Study On Effect Of Added Neutralisers On Starter Culture Growth In Fermented Milks

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Rajanna.M

2017-06-01

Full Text Available The Dairy starter culture is referred to carefully selection of desirable microorganisms. Those are intentionally added to milk during conversion into cheese dahi yoghurt and other fermented dairy products to bring about specific changes in the appearance body and texture flavor and desired organoleptic characteristics of the final product. The quality of milk itself has an important bearing on the growth of starter organisms. The mastitis milk has abnormal in composition and such milk with high salt concentration does not support the growth of starter culture that leads to production of poor quality of fermented dairy products with week body.. The presence of certain neutralizing substances performed in milk has found to interfere with growth of starters. There was a definite lag in the growth of the starter organisms as well as acid development when neutralizers were added to raw milk samples. This may be due to the bacteriostatic effect of added neutralizers. But discrepancy was seen to the greatest extent in the case of neutralized mastitis and highly advanced lactation milks and to a lesser degree on the early lactation milk obtained on the 4th and 5th days.

Butanol by fermentation

Energy Technology Data Exchange (ETDEWEB)

Hongo, M

1960-07-19

BuOH is produced by inoculating a carbohydrate mash with Clostridium saccharoperbutylacetonicum (ATCC 13564), fermenting the inoculated mash, and recovering the BuOH by fractional distillation. Thus, a medium containing sugar 4, (NH/sub 4/)/sub 2/SO/sub 4/ 0.2, Ca superphosphate 0.1, and CoCO/sub 3/ 0.3% is inoculated with a C. saccharoperbutylacetonicum culture and cultivated at 30/sup 0/ until the acidity begins to decrease. Then the culture is transferred to a second medium of similar composition. This transfer is repeated a third time, and then the culture is transferred to the main mash (same composition) and fermented for 60 hours at 30/sup 0/. The yield of BuOH is 11.5 g/1 or 25.5% of the sugar supplied.

An improved simplified model predictive control algorithm and its application to a continuous fermenter

Directory of Open Access Journals (Sweden)

W. H. Kwong

2000-06-01

Full Text Available The development of a new simplified model predictive control algorithm has been proposed in this work. The algorithm is developed within the framework of internal model control, and it is easy to understanding and implement. Simulation results for a continuous fermenter, which show that the proposed control algorithm is robust for moderate variations in plant parameters, are presented. The algorithm shows a good performance for setpoint tracking.

Acetic acid bacteria in fermented foods and beverages.

Science.gov (United States)

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.

Alcoholic fermentation of whey

Energy Technology Data Exchange (ETDEWEB)

Beach, A S; Holland, J W

1958-09-10

The lactose of whey and other milk products is rapidly fermented to ethanol by means of Candida pseudotropicalis strain XI. The fermentation is complete in about 12 hours and yields about 45% ethanol based on the weight of lactose. Conditions favoring the fermentation and inhibiting lactic acid production include pH 4.5, 30/sup 0/, and continuous aeration.

Application of near-infrared spectroscopy for monitoring and control of cell culture and fermentation.

Science.gov (United States)

Cervera, Albert E; Petersen, Nanna; Lantz, Anna Eliasson; Larsen, Anders; Gernaey, Krist V

2009-01-01

Near-infrared (NIR) spectroscopy can potentially provide on-line information on substrate, biomass, product, and metabolite concentrations in fermentation processes, which could be useful for improved monitoring or control. However, several factors can negatively influence the quality of chemometric models built for interpretation of the spectra, thus impairing the analyte concentration predictions. The aim of this review was to provide an overview of necessary conditions and challenges that one has to face when developing a NIR application for monitoring of cell culture or fermentation processes. Important practical aspects are introduced, such as sampling, modeling of biomass concentration, influence of microorganism morphology on the spectra, effects of the hydrodynamic conditions in the fermenter, temperature influence, instrument settings, and signal optimization. Several examples from the literature are provided, which will hopefully guide the reader interested in the topic. Furthermore, the general procedure used for the development of calibration models is presented, and the influence of microorganism metabolism-potential source of correlation between analytes-is commented. Other important issues such as wavelength selection and evaluation of robustness are shortly introduced. Finally, some examples of potential applications of NIR monitoring are provided, including the implementation of control strategies, the combination with other monitoring tools (the so-called sensor fusion), and the description of process trajectories. On the basis of the review, we conclude that acceptance of NIR spectroscopy as a standard monitoring tool by the fermentation industry will necessitate considerably more on-line studies using industrially relevant-and highly challenging-fermentation conditions (high aeration intensity, high biomass concentration and viscosity, and filamentous production strain). (c) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009.

Chemical, Physiochemical, and Microstructural Properties, and Probiotic Survivability of Fermented Goat Milk Using Polymerized Whey Protein and Starter Culture Kefir Mild 01.

Science.gov (United States)

Wang, Hao; Wang, Cuina; Wang, Mu; Guo, Mingruo

2017-11-01

A set-type fermented goat milk (FGM) using polymerized whey protein (PWP) as main thickening agent and Kefir Mild 01 as starter culture was developed. The FGM with PWP (0.3%, w/v) and pectin (0.2%, w/v) had low syneresis (5.44 ± 0.92%), desirable viscosity (952.86 ± 61.52 mPa⋅s), and hardness (112.57 ± 3.23 g), which were comparable to a fermented cow milk. Sensory evaluation data showed that the FGM with PWP and pectin had higher scores of both flavor (4.41 ± 0.39) and taste (3.72 ± 0.34) than the sample without PWP. Chemical composition of both fermented goat and cow milk were analyzed. The protein content of goat and cow milk samples were 3.50% ± 0.12% and 3.28% ± 0.09% (w/w), respectively. Lactobacillus acidophilus population in both FGM samples remained above 10 6 CFU/g during the 1st 4-wk storage. There was a slight but no significant (P > 0.05) decrease in pH and TA during storage. Scanning electron microscopy micrographs displayed a compact and homogeneous protein network of the FGM with PWP and pectin. Polymerized whey protein may be a novel protein-based thickening agent for formulation of a set-type FGM with starter culture Kefir Mild 01. Fermented goat milk is an increasingly popular dairy product in the world. However, it is difficult to make set type fermented goat milk due to the smaller size and lower content of casein micelles in goat milk. A fermented goat milk with PWP (0.3%, w/v) and pectin (0.2%, w/v) was successfully developed in this study. The product fermented by Kefir Mild 01 starter culture had a similar taste with Kefir but no yeast or alcoholic exists. The new product would be a promising food in the market. © 2017 Institute of Food Technologists®.

Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate-reducing benthic microbial populations.

Science.gov (United States)

Saad, Sainab; Bhatnagar, Srijak; Tegetmeyer, Halina E; Geelhoed, Jeanine S; Strous, Marc; Ruff, S Emil

2017-12-01

For the anaerobic remineralization of organic matter in marine sediments, sulfate reduction coupled to fermentation plays a key role. Here, we enriched sulfate-reducing/fermentative communities from intertidal sediments under defined conditions in continuous culture. We transiently exposed the cultures to oxygen or nitrate twice daily and investigated the community response. Chemical measurements, provisional genomes and transcriptomic profiles revealed trophic networks of microbial populations. Sulfate reducers coexisted with facultative nitrate reducers or aerobes enabling the community to adjust to nitrate or oxygen pulses. Exposure to oxygen and nitrate impacted the community structure, but did not suppress fermentation or sulfate reduction as community functions, highlighting their stability under dynamic conditions. The most abundant sulfate reducer in all cultures, related to Desulfotignum balticum, appeared to have coupled both acetate- and hydrogen oxidation to sulfate reduction. We describe a novel representative of the widespread uncultured candidate phylum Fermentibacteria (formerly candidate division Hyd24-12). For this strictly anaerobic, obligate fermentative bacterium, we propose the name ' U Sabulitectum silens' and identify it as a partner of sulfate reducers in marine sediments. Overall, we provide insights into the function of fermentative, as well as sulfate-reducing microbial communities and their adaptation to a dynamic environment. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

Improved glycerol production from cane molasses by the sulfite process with vacuum or continuous carbon dioxide sparging during fermentation

Energy Technology Data Exchange (ETDEWEB)

Kalle, G.P.; Naik, S.C.; Lashkari, B.Z.

1985-01-01

The conventional sulfite process for glycerol production from molasses using Saccharomyces cerevisiae var. Hansen was modified to obtain product concentrations of up to 230 g/l and productivity of 15 g/l.d by fermenting under vacuum (80 mm) or with continuous sparging of CO2 (0.4 vvm). Under these conditions the requirement of sulfite for optimum production of glycerol was reduced by two thirds (20 g/l), the ethanol concentration in the medium was kept below 30 g/l and the competence of yeast cells to ferment was conserved throughout the fermentation period for up to 20 days. In addition to the above, the rate of incorporation of sulfite had a significant effect on glucose fermentation and glycerol yields. There was an optimal relationship between glycerol yields and the molar ratio of sulfite to glucose consumed, which for cane molasses was 0.67. This ratio was characteristic of the medium composition.

Improved glycerol production from cane molasses by the sulfite process with vacuum or continuous carbon dioxide sparging during fermentation

Energy Technology Data Exchange (ETDEWEB)

Kalle, G.P.; Naik, S.C.; Lashkari, B.Z.

1985-01-01

The conventional sulfite process for glycerol production from molasses using Saccharomyces cerevisiae var. Hansen was modified to obtain product concentrations of up to 230 g/l and productivity of 15 g/l x d by fermenting under vacuum (80 mm) or with continuous sparging of CO/sub 2/ (0.4 vvm). Under these conditions the requirement of sulfite for optimum production of glycerol was reduced by two thirds (20 g/l), the ethanol concentration in the medium was kept below 30 g/l and the competence of yeast cells to ferment was conserved throughout the fermentation period for up to 20 days. In addition to the above, the rate of incorporation of sulfite had a significant effect on glucose fermentation and glycerol yields. There was an optimal relationship between glycerol yields and the molar ratio of sulfite to glucose consumed, which for cane molasses was 0.67. This ratio was characteristic of the medium composition. 10 references, 4 figures, 3 tables.

Method for sustaining microorganism culture in syngas fermentation process in decreased concentration or absence of various substrates

Science.gov (United States)

Adams, Stephen S.; Scott, Syrona; Ko, Ching-Whan

2015-05-19

The present invention relates to methods for sustaining microorganism culture in a syngas fermentation reactor in decreased concentration or absence of various substrates comprising: adding carbon dioxide and optionally alcohol; maintaining free acetic acid concentrations; and performing the above mentioned steps within specified time.

Microbiology and optimization of hydrogen fermentation and bioelectricity production

Energy Technology Data Exchange (ETDEWEB)

Makinen, A.

2013-11-01

This work investigated dark fermentative hydrogen (H{sub 2}) and bioelectricity production from carbohydrates. Meso- and thermophilic fermentative and mesophilic exoelectrogenic bacteria were enriched from different natural sources. The H{sub 2} production from different hexoses and pentoses, them main constituents of lignocellulose, was studied in batch assays. H{sub 2} production from xylose was examined in continuous stirred tank reactor (CSTR). Operational parameters for H{sub 2} production were optimized. Bioelectricity production was studied in microbial fuel cells and process parameters were optimized. Dynamics of microbial communities in H{sub 2} and bioelectricity production processes were determined. A novel thermophilic dark fermentative H{sub 2} producing bacterium, Thermovorax subterraneus, was enriched and isolated from geothermal underground mine. T. subterraneus had the optimum growth temperature of 72 deg C and the maximum H{sub 2} yield of 1.4 mol/mol glucose in batch assay. The main soluble fermentative end products of T. subterraneus were acetate and ethanol. Thermophilic dark fermentative mixed culture enriched from hot spring (Hisarlan, Turkey) had the maximum H{sub 2} yield of 1.7 mol/mol glucose. The optimal environmental parameters to maximize H{sub 2} yield were temperature 52 deg C, initial pH 6.5, 40 mg/L Fe{sup 2+}, 4.5 g/L yeast extract and glucose concentration of 4 g/L. Increasing the glucose concentration to 18 g/L increased the maximum H{sub 2} production rate to 56.2 mmol H{sub 2}/h/L. Environmental parameters had a significant effect on metabolic pathways of fermentation. Another hot spring (Hisarkoy, Turkey) enrichment culture was able to ferment different sugars to H{sub 2} favoring pentoses over hexoses. The best H{sub 2} yields in batch assays were obtained from pentoses: xylose, arabinose and ribose yielded 21, 15 and 8 % of the theoretical yield, respectively; whilst on glucose the yield was only 2 % of the theoretical

Incorporation of tritium into planctonic algae in a continuous culture under dynamic conditions

International Nuclear Information System (INIS)

Strack, S.; Kistner, G.; Emeis, C.C.

1979-01-01

For the purpose of modelling the ecologic behaviour of organically bound tritium (OBT) in aquatic food chains under dynamic conditions (i.e. by changing tritium concentrations), a continuous culture of algae was chosen to which tritium was added by a single injection as tritiated water (HTO). The culture was working according to the chemostatic principle where the concentration of cells is in a steady state. Therefore, according to the growth of algae, tritium is incorporated into the organic substance, while in a parallel process HTO and algae are eliminated from the system at the same rate. From these two processes of first-order kinetics, a special function resulted for the concentration process of OBT in the fermenter that is well known in the field of drug kinetics. Initially it increases until it reaches a maximum value where it intersects the elimination curve of HTO, then decreases and asymptotically approaches the time axis - in the same manner as the elimination curve - only at a superior level. A comparison of this theoretically calculated function with the concentration actually found shows that also under dynamic conditions tritium is undergoing discrimination because of isotopic effects up to a ratio of I=0.80. The calculation of the ratios R=(OBT)/(HTO) in the continuous culture by comparing the function for OBT with the elimination curve for HTO shows a linear increase of R-values during the experiment. At maximum tritium concentration in the algae, the ratio becomes greater than one, and at the end of the experiment it reaches a value of about 6. However, by extrapolating to a time of 40 half-lives, when the absolute concentration of HTO has already decreased by a factor of 10 -12 , a ratio of about 25 was found. The discrimination enters the estimation of R-values at a constant factor of 0.80. (author)

Inhibitory effect of essential oils against Lactobacillus rhamnosus and starter culture in fermented milk during its shelf-life period

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Cristiane Mengue Feniman Moritz

2012-09-01

Full Text Available The use of essential oils in foods has attracted great interest, due to their antagonistic action against pathogenic microorganisms. However, this action is undesirable for probiotic foods, as products containing Lactobacillus rhamnosus. The aim of the present study was to measure the sensitivity profile of L. rhamnosus and a yogurt starter culture in fermented milk, upon addition of increasing concentrations of cinnamon, clove and mint essential oils. Essential oils were prepared by steam distillation, and chemically characterised by gas chromatography-mass spectrometry (GC-MS and determination of density. Survival curves were obtained from counts of L. rhamnosus and the starter culture (alone and in combination, upon addition of 0.04% essential oils. In parallel, titratable acidity was monitored over 28 experimental days. Minimum inhibitory concentration values, obtained using the microdilution method in Brain Heart Infusion medium, were 0.025, 0.2 and 0.4% for cinnamon, clove and mint essential oils, respectively. Cinnamon essential oil had the highest antimicrobial activity, especially against the starter culture, interfering with lactic acid production. Although viable cell counts of L. rhamnosus were lower following treatment with all 3 essential oils, relative to controls, these results were not statistically significant; in addition, cell counts remained greater than the minimum count of 10(8CFU/mL required for a product to be considered a probiotic. Thus, although use of cinnamon essential oil in yogurt makes starter culture fermentation unfeasible, it does not prevent the application of L. rhamnosus to probiotic fermented milk. Furthermore, clove and mint essential oil caused sublethal stress to L. rhamnosus.

Stable acetate production in extreme-thermophilic (70ºC) mixed culture fermentation by selective enrichment of hydrogenotrophic methanogens

NARCIS (Netherlands)

Zhang, F.; Zhang, Y.; Ding, J.; Dai, K.; Van Loosdrecht, M.C.M.; Zeng, R.J.

2014-01-01

The control of metabolite production is difficult in mixed culture fermentation. This is particularly related to hydrogen inhibition. In this work, hydrogenotrophic methanogens were selectively enriched to reduce the hydrogen partial pressure and to realize efficient acetate production in

Novel Method of Lactic Acid Production by Electrodialysis Fermentation

OpenAIRE

Hongo, Motoyoshi; Nomura, Yoshiyuki; Iwahara, Masayoshi

1986-01-01

In lactic acid fermentation by Lactobacillus delbrueckii, the produced lactic acid affected the lactic acid productivity. Therefore, for the purpose of alleviating this inhibitory effect, an electrodialysis fermentation method which can continuously remove produced lactic acid from the fermentation broth was applied to this fermentation process. As a result, the continuation of fermentation activity was obtained, and the productivity was three times higher than in non-pH-controlled fermentati...

Butyric acid fermentation of sodium hydroxide pretreated rice straw with undefined mixed culture.

Science.gov (United States)

Ai, Binling; Li, Jianzheng; Chi, Xue; Meng, Jia; Liu, Chong; Shi, En

2014-05-01

This study describes an alternative mixed culture fermentation technology to anaerobically convert lignocellulosic biomass into butyric acid, a valuable product with wide application, without supplementary cellulolytic enzymes. Rice straw was soaked in 1% NaOH solution to increase digestibility. Among the tested pretreatment conditions, soaking rice straw at 50°C for 72 h removed ~66% of the lignin, but retained ~84% of the cellulose and ~71% of the hemicellulose. By using an undefined cellulose-degrading butyrate-producing microbial community as butyric acid producer in batch fermentation, about 6 g/l of butyric acid was produced from the pretreated rice straw, which accounted for ~76% of the total volatile fatty acids. In the repeated-batch operation, the butyric acid production declined batch by batch, which was most possibly caused by the shift of microbial community structure monitored by denaturing gradient gel electrophoresis. In this study, batch operation was observed to be more suitable for butyric acid production.

Evaluation of a functional soy product with addition of soy fiber and fermented with probiotic kefir culture

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Tahis Regina Baú

2014-06-01

Full Text Available The objective of this study was to evaluate the chemical, sensory properties and stability of a functional soy product with soy fiber and fermented with probiotic kefir culture. The product was characterized by the chemical composition, color and sensory analysis. The stability of the product was evaluated by pH, acidity, viscosity, firmness, syneresis measurements and cells counts. The functional soy product presented better chemical composition and difference in color compared to the fermented product without fiber. Sensory analysis showed that the functional soy product had good acceptance and had better firmness and reduced syneresis compared to fermented product without fiber. The lactic acid bacteria counts decreased slightly during 28 days at 4°C of the storage and the product showed good microbiological stability. The functional soy product due to high Lactococcus lactis counts could be considered as a probiotic for the entire storage period.

Traditional fermented foods and beverages of Namibia

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Jane Misihairabgwi

2017-09-01

Conclusion: Fermented foods and beverages play a major role in the diet, socioeconomic, and cultural activities of the Namibian population. Most are spontaneously fermented. Research is scarce and should be conducted on the microbiology, biochemistry, nutritional value, and safety of the fermented foods and beverages to ensure the health of the population.

Influence of aeration in the fermentative activity of Kloeckera apiculata during fermentation of apple juice

International Nuclear Information System (INIS)

Estela Escalante, Waldir D; Rychtera, Mojmir; Melzoch, Karel; Guerrero Ochoa, Manuel R

2012-01-01

The influence of aeration on the fermentative activity of Kloeckera apiculata RIVE 9-2-1 was studied in order to evaluate the production of metabolites of the fermentation. To achieve this, the strain was cultured in Erlenmeyer flasks containing sterilized and aroma removed apple juice, and the chemical compounds produced during fermentation in shaken (200 min-1) and static (without agitation) cultivation were determined. The results showed that the agitation of the culture medium increases production of higher alcohols (till 591.0 mg/L) compared to static cultivation, whereas on the contrary, the production of acetic acid, ethyl acetate and glycerol (260.0 ± 11.0 mg/L, 196.0 ± 10.0 mg/L y 2.6±0.2 g/L) were higher compared to shaken cultivation (222.0 ± 8.0 mg/L, 96.0 ± 4.5 mg/L and 1.8 ± 0.2 g/L) respectively. Batch cultivations carried out in bioreactor with air flux of 25 l/h reported a growth rate μ of 0.17 h-1, production of ethanol (12.5 ± 2.0 g/L) and other compounds typically produced during alcoholic fermentation. The concentration of dissolved oxygen in the fermentation medium affects its metabolism thus; insufficient amounts of oxygen would provoke a respirofermentative metabolism. The best results in terms of organoleptic quality of the fermented beverage regarding to aroma, taste and flavor was obtained when fermented in static cultivation. The control of aeration during fermentation can be used to control the synthesis of chemical compounds of sensory impact in the production of fermented beverages.

An optimized fed-batch culture strategy integrated with a one-step fermentation improves L-lactic acid production by Rhizopus oryzae.

Science.gov (United States)

Fu, Yongqian; Sun, Xiaolong; Zhu, Huayue; Jiang, Ru; Luo, Xi; Yin, Longfei

2018-05-21

In previous work, we proposed a novel modified one-step fermentation fed-batch strategy to efficiently generate L-lactic acid (L-LA) using Rhizopus oryzae. In this study, to further enhance efficiency of L-LA production through one-step fermentation in fed-batch cultures, we systematically investigated the initial peptone- and glucose-feeding approaches, including different initial peptone and glucose concentrations and maintained residual glucose levels. Based on the results of this study, culturing R. oryzae with initial peptone and glucose concentrations of 3.0 and 50.0 g/l, respectively, using a fed-batch strategy is an effective approach of producing L-LA through one-step fermentation. Changing the residual glucose had no obvious effect on the generation of L-LA. We determined the maximum LA production and productivity to be 162 g/l and 6.23 g/(l·h), respectively, during the acid production stage. Compared to our previous work, there was almost no change in L-LA production or yield; however, the productivity of L-LA increased by 14.3%.

Continuous fed-batch vacuum fermentation system for glycerol from molasses by the sulfite process

Energy Technology Data Exchange (ETDEWEB)

Kalle, G.P.; Naik, S.C.

1985-01-01

A continuous fed-batch vacuum fermentation system has been described for the production of glycerol from cane molasses (and juice) by a conventional sulfite process. A glycerol concentration of 80 g/l was achieved with a productivity of 30 g/l/day at a dilution rate of 0.4/day which is twice that from a vacuum batch process (15 g/l/day) or four times that obtained without vacuum (8 g/l/day). 8 references.

Obtaining fermented dairy products with the yogurt culture YF-L 812

Directory of Open Access Journals (Sweden)

INA VASILEAN

2011-07-01

Full Text Available Exopolysaccharides (EPS produced by some lactic acid bacteria cultures can efficiently replace commercial stabilizers for preventing or reducing syneresis, providing fermented milk products with suitable structure viscosity. The effect of EPS on food quality characteristics depends on the EPS properties themselves, as well as their interaction with various components of the food system. This paper was aimed at studying the influence of the environment composition on the EPS biosynthesis by starter culture YF-L 812 and at determining the properties of at yogurt obtained. High fat content of milk (3.5% and 1.5% had a positive effect on yogurt texture. In order to reduce the syneresis phenomenon, the milk with low fat content (0.1% was supplemented with different concentrations of milk powder and lactose. Our results indicated that the whey separated was reduced to 0.6% and 0.3% when the milk was supplemented with 2% lactose and 2% skimmed milk powder, and respectively, 3% lactose and 3% skimmed milk powder.

Fermentation of Nocellara Etnea Table Olives by Functional Starter Cultures at Different Low Salt Concentrations

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Alessandra Pino

2018-06-01

Full Text Available Nocellara Etnea is one of the main Sicilian cultivars traditionally used to produce both olive oil and naturally fermented table olives. In the present study, the effect of different salt concentrations on physico-chemical, microbiological, sensorial, and volatile organic compounds (VOCs formation was evaluated in order to obtain functional Nocellara Etnea table olives. The experimental design consisted of 8 treatments as follow: fermentations at 4, 5, 6, and 8% of salt with (E1-E4 samples and without (C1-C4 samples the addition of starters. All the trials were carried out at room temperature (18 ± 2°C and monitored for an overall period of 120 d. In addition, the persistence of the potential probiotic Lactobacillus paracasei N24 at the end of the process was investigated. Microbiological data revealed the dominance of lactic acid bacteria (LAB, starting from the 7th d of fermentation, and the reduction of yeasts and enterobacteria in the final product inoculated with starters. VOCs profile highlighted a high amount of aldehydes at the beginning of fermentation, which significantly decreased through the process and a concomitant increase of alcohols, acids, esters, and phenols. In particular, esters showed an occurrence percentage higher in experimental samples rather than in control ones, contributing to more pleasant flavors. Moreover, acetic acid, ethanol, and phenols, which often generate off-flavors, were negatively correlated with mesophilic bacteria and LAB. It is interesting to note that salt content did not affect the performances of starter cultures and slightly influenced the metabolome of table olives. Sensory data demonstrated significant differences among samples registering the highest overall acceptability in the experimental sample at 5% of NaCl. The persistence of the L. paracasei N24 strain in experimental samples, at the end of the process, revealed its promising perspectives as starter culture for the production of

Determination of volatile components in fermented soybean prepared by a co-culture of Bacillus subtilis and Rhizopus oligosporus

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Chukeatirote, E.,

2017-07-01

Full Text Available Fermented soybeans are traditional foods widely consumed in many countries (i.e., Natto in Japan, Jang in Korea, Kinema in India, Douichi in China, and Thua Nao in Thailand. In this study, an attempt was made with an expectation to improve the fermentation process using a co-culture of Bacillus subtilis and Rhizopus oligosporus. Initially, the raw soybeans were washed, sterilized by autoclaving, and inoculated with two inocula; for this, three different ratios between B. subtilis and R. oligosporus used were 100:0, 50:50, and 0:100. The fermentation was then carried out at 30°C for 3 days. The volatile compounds in the non-fermented and the fermented soybean products were determined by gas chromatography/ mass spectrometry (GC/MS and extracted using a solid phase microextraction (SPME technique. In total, 165 compounds were identified in the non-fermented and the fermented soybean products. For the non-fermented products, the predominant volatile compounds were alcohols (25.81%, aldehydes (13.64%, acids and esters (7.57%, furans (6.13% and ketones (0.88%. In contrast, the major volatiles compounds presented in the fermented soybeans were as follows: i The treatment of 100:0 consisted of acids and esters (35.89%, alcohols (14.55%, aldehydes (8.72%, ketones (4.97%, pyrazines (4.87%, and furans (4.22%; ii 50:50 comprised of acids and esters (55.62%, alcohols (16.22%, aldehydes (7.80%, pyrazine (3.65%, ketones (2.55%, furans (1.67%, and aromatic compounds (1.46%; and iii 0:100 included acids and esters (66.50%, alcohols (15.44%, aldehydes (2.59%, ketones (2.72%, furans (1.89%, aromatic compounds (1.80%, pyrazines (1.35%, and sulphur containing compounds (0.24% respectively.

Tradition and Agency. Tracing cultural continuity and invention

DEFF Research Database (Denmark)

Tradition helps ensure continuity and stability in human affairs, signifying both the handing down of cultural heritage from one generation to the next, and the particular customs, beliefs and rituals being handed down. In the social sciences, tradition has been a central concept from the very st...... address the larger questions of cultural continuity, agency and the use of cultural resources. In the postscript, Terence Ranger offers a complementary perspective by tracing the effects of nationalism, imperialism and globalised exchange on tradition.......Tradition helps ensure continuity and stability in human affairs, signifying both the handing down of cultural heritage from one generation to the next, and the particular customs, beliefs and rituals being handed down. In the social sciences, tradition has been a central concept from the very...... revolutionize the understanding of tradition in anthropology, history and sociology, stimulating an enormous amount of research on invented and imagined traditions. However, most of this research has focussed on the cultural dynamics of specific local innovations and reactions to global developments...

Ziziphus mauritiana (masau) fruits fermentation in Zimbabwe: from black-box to starter culture development

OpenAIRE

Nyanga, L.K.

2012-01-01

This thesis reports on studies of microbiological and biochemical properties of masau (Ziziphus mauritiana) fruit fermentation and the development of starter cultures for the production of masau beverages. A survey to document the traditional processing techniques was conducted using a questionnaire and focus group discussions in each of the three districts, i.e., Mudzi, Mt Darwin and Muzarabani in Zimbabwe. The survey results showed that the masau fruit is usually gathered by women and chi...

Evolutionary Engineering in Chemostat Cultures for Improved Maltotriose Fermentation Kinetics in Saccharomyces pastorianus Lager Brewing Yeast

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Anja Brickwedde

2017-09-01

Full Text Available The lager brewing yeast Saccharomyces pastorianus, an interspecies hybrid of S. eubayanus and S. cerevisiae, ferments maltotriose, maltose, sucrose, glucose and fructose in wort to ethanol and carbon dioxide. Complete and timely conversion (“attenuation” of maltotriose by industrial S. pastorianus strains is a key requirement for process intensification. This study explores a new evolutionary engineering strategy for improving maltotriose fermentation kinetics. Prolonged carbon-limited, anaerobic chemostat cultivation of the reference strain S. pastorianus CBS1483 on a maltotriose-enriched sugar mixture was used to select for spontaneous mutants with improved affinity for maltotriose. Evolved populations exhibited an up to 5-fold lower residual maltotriose concentration and a higher ethanol concentration than the parental strain. Uptake studies with 14C-labeled sugars revealed an up to 4.75-fold higher transport capacity for maltotriose in evolved strains. In laboratory batch cultures on wort, evolved strains showed improved attenuation and higher ethanol concentrations. These improvements were also observed in pilot fermentations at 1,000-L scale with high-gravity wort. Although the evolved strain exhibited multiple chromosomal copy number changes, analysis of beer made from pilot fermentations showed no negative effects on flavor compound profiles. These results demonstrate the potential of evolutionary engineering for strain improvement of hybrid, alloploid brewing strains.

Evolutionary Engineering in Chemostat Cultures for Improved Maltotriose Fermentation Kinetics in Saccharomyces pastorianus Lager Brewing Yeast.

Science.gov (United States)

Brickwedde, Anja; van den Broek, Marcel; Geertman, Jan-Maarten A; Magalhães, Frederico; Kuijpers, Niels G A; Gibson, Brian; Pronk, Jack T; Daran, Jean-Marc G

2017-01-01

The lager brewing yeast Saccharomyces pastorianus , an interspecies hybrid of S. eubayanus and S. cerevisiae , ferments maltotriose, maltose, sucrose, glucose and fructose in wort to ethanol and carbon dioxide. Complete and timely conversion ("attenuation") of maltotriose by industrial S. pastorianus strains is a key requirement for process intensification. This study explores a new evolutionary engineering strategy for improving maltotriose fermentation kinetics. Prolonged carbon-limited, anaerobic chemostat cultivation of the reference strain S. pastorianus CBS1483 on a maltotriose-enriched sugar mixture was used to select for spontaneous mutants with improved affinity for maltotriose. Evolved populations exhibited an up to 5-fold lower residual maltotriose concentration and a higher ethanol concentration than the parental strain. Uptake studies with 14 C-labeled sugars revealed an up to 4.75-fold higher transport capacity for maltotriose in evolved strains. In laboratory batch cultures on wort, evolved strains showed improved attenuation and higher ethanol concentrations. These improvements were also observed in pilot fermentations at 1,000-L scale with high-gravity wort. Although the evolved strain exhibited multiple chromosomal copy number changes, analysis of beer made from pilot fermentations showed no negative effects on flavor compound profiles. These results demonstrate the potential of evolutionary engineering for strain improvement of hybrid, alloploid brewing strains.

Fermentative hydrogen production by Clostridium butyricum CWBI1009 and Citrobacter freundii CWBI952 in pure and mixed cultures

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Beckers, L.

2010-01-01

Full Text Available This paper investigates the biohydrogen production by two mesophilic strains, a strict anaerobe (Clostridium butyricum CWBI1009 and a facultative anaerobe (Citrobacter freundii CWBI952. They were cultured in pure and mixed cultures in serum bottles with five different carbon sources. The hydrogen yields of pure C. freundii cultures ranged from 0.09 molH2.molhexose-1 (with sucrose to 0.24 molH2.molhexose-1 (with glucose. Higher yields were obtained by the pure cultures of Cl. butyricum ranging from 0.44 molH2.molhexose-1 (with sucrose to 0.69 molH2.molhexose-1 (with lactose. This strain also fermented starch whereas C. freundii did not. However, it consumed the other substrates faster and produced hydrogen earlier than Cl. butyricum. This ability has been used to promote the growth conditions of Cl. butyricum in co-culture with C. freundii, since Cl. butyricum is extremely sensitive to the presence of oxygen which strongly inhibits H2 production. This approach could avoid the addition of any expensive reducing agents in the culture media such as L-cysteine since C. freundii consumes the residual oxygen. Thereafter, co-cultures with glucose and starch were investigated: hydrogen yields decreased from 0.53 molH2.molhexose-1 for pure Cl. butyricum cultures to 0.38 molH2.molhexose-1 for mixed culture with glucose but slightly increased with starch (respectively 0.69 and 0.73 molH2.molhexose-1. After 48 h of fermentation, metabolites analysis confirmed with microbial observation, revealed that the cell concentration of C. freundii dramatically decreased or was strongly inhibited by the development of Cl. butyricum.

Effect of sprouted barley grain supplementation of an herbage or haylage diet on ruminal fermentation and methane output in continuous culture

Science.gov (United States)

A 4-unit dual-flow continuous culture fermentor system was used to assess the effect of supplementing 7-d sprouted barley (SB) or barley grain (BG), with a pasture (orchardgrass) or haylage diet, on nutrient digestibility, VFA production, bacterial protein synthesis, and methane production. Treatmen...

Feeding Aspergillus oryzae Fermentation Culture (AOFC to Growing Sheep: 1. The Effect of AOFC on Rumen Fermentation

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Darwinsyah Lubis

2002-10-01

Full Text Available Cultures of fungi, especially Aspergillus oryzae, have been of interest to animal nutritionists to increase feed efficiency. Many experiments have been done and showed positive results on rumen fermentation and productivity of ruminants. This paper reports the results of an in vivo study on feeding Aspergillus oryzae, fermentation culture (AOFC to growing sheep. ‘Onggok’ (tapioca processing waste was used as media for AO cultivation after being enriched with a mineral mixture. Commercial concentrate (GT-03 was fed to 15 growing sheep supplemented with 0% (C0, 5% (C1, and 10% (C2 AOFC (w/w. Chopped fresh King grass was used as a basal diet. The 3 treatments were randomly allotted to the sheep according to randomized block design with 5 replications. The study was carried out for 14 weeks. Digestion trial was conducted in the last 10 days of experiment. All feed and fecal samples were analyzed for nutrients. Rumen fluid was sampled at the mid experimental period. Analyses were done on rumen pH, ammonia content, (VFA volatile fatly acids concentration, and also total digestive tract digestibility of dry and organic matter, crude protein, and total fiber (NDF. Differences in treatment means were analyzed by Duncan’s MRT. Feeding AOFC resulted in increased (P<0.05 digestibility of crude protein from 59.6% in control sheep to 65.5% in sheep fed concentrate with 10% AOFC supplementation. The same pattern also occurred for NDF, but no effect was found on dry and organic matter. Higher fiber digestibility with AOFC supplementation was in line with an increase (P<0.05 in cellulolytic bacteria population in the rumen. VFA produced also increased (P<0.05, as well as individual acids content, primarily acetate and propionate. No differences (P<0.05 were detected in rumen pH and ammonia content. It appears that AOFC is more suitable for the purpose of meat production.

Ethanol fermentation by immobilized cells of Zymomonas mobilis

Energy Technology Data Exchange (ETDEWEB)

Grote, W.

1985-01-01

Previous studies have shown that immobilized yeast cell cultures have commercial potential for fuel ethanol production. In this study the suitability of strains of Z. mobilis for whole cell immobilization was investigated. Experiments revealed that immobilization in Ca-alginate or K-carrageenan gel or use of flocculating strains was effective for ethanol production at relatively high productivities. Two laboratory size reactors were designed and constructed. These were a compartmented multiple discshaft column and a tower fermentor. Results of this work supported other studies that established that growth and fermentation could be uncoupled. The data indicated that specific metabolic rates were dependent on the nature of the fermentation media. The addition of lactobacilli to Z. mobilis continuous fermentations had only a transient effect, and was unlikely to affect an immobilized Z. mobilis process. With 150 gl/sup -1/ glucose media and a Z. mobilis ZM4 immobilized cell reactor, a maximum volumetric ethanol productivity of 55 gl/sup -1/h/sup -1/ was obtained. The fermentation of sucrose media or sucrose-based raw materials (molasses, cane juice, synthetic mill liquor) by immobilized Z. mobilis ZM4 revealed a pattern of rapid sucrose hydrolysis, preferential glucose utilization and the conversion of fructose to the undesirable by-products levan and sorbitol.

Studies of Saccharomyces cerevisiae and Non-Saccharomyces Yeasts during Alcoholic Fermentation

DEFF Research Database (Denmark)

Kemsawasd, Varongsiri

The early death of non-Saccharomyces yeasts during mixed culture spontaneous wine fermentation has traditionally been attributed to the lower capacity of these yeast species to withstand high levels of ethanol, low pH, and other media properties that are a part of progressing fermentation. However......, other yeast-yeast interactions, such as cell-cell contact mediated growth arrest and/or toxininduced death may also be a significant factor in the relative fragility of these non-Saccharomyces yeasts in mixed culture fermentation. In the present work we evaluate the combined roles of cell-cell contact...... and/or antimicrobial peptides on the early death of Lachancea thermotolerans during mixed culture fermentations with Saccharomyces cerevisiae. Using a specially designed double compartment fermentation system, we established that both cell-to-cell contact and antimicrobial peptides contribute...

Ethanol production by repeated batch and continuous fermentations of blackstrap molasses using immobilized yeast cells on thin-shell silk cocoons

International Nuclear Information System (INIS)

Rattanapan, Anuchit; Limtong, Savitree; Phisalaphong, Muenduen

2011-01-01

Highlights: → Thin-shell silk cocoons for immobilization of Saccharomycescerevisiae. → Advantages: high mechanical strength, light weight, biocompatibility and high surface area. → Enhanced cell stability and ethanol productivity by the immobilization system. -- Abstract: A thin-shell silk cocoon (TSC), a residual from the silk industry, is used as a support material for the immobilization of Saccharomyces cerevisiae M30 in ethanol fermentation because of its properties such as high mechanical strength, light weight, biocompatibility and high surface area. In batch fermentation with blackstrap molasses as the main fermentation substrate, an optimal ethanol concentration of 98.6 g/L was obtained using a TSC-immobilized cell system at an initial reducing sugar concentration of 240 g/L. The ethanol concentration produced by the immobilized cells was 11.5% higher than that produced by the free cells. Ethanol production in five-cycle repeated batch fermentation demonstrated the enhanced stability of the immobilized yeast cells. Under continuous fermentation in a packed-bed reactor, a maximum ethanol productivity of 19.0 g/(L h) with an ethanol concentration of 52.8 g/L was observed at a 0.36 h -1 dilution rate.

Mathematical modeling of continuous ethanol fermentation in a membrane bioreactor by pervaporation compared to conventional system: Genetic algorithm.

Science.gov (United States)

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.

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

Science.gov (United States)

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 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.

Exploration of Yeast and Bacteria Contaminants in Seed Culture and Fermented Wort from Gyo Gon Alcohol Distillery

International Nuclear Information System (INIS)

Ngwe Thein

2005-10-01

Study was made on samples of seed culture and fermented wort from Gyogon alcohol distillery. In all samples bacteria contaminants were observed. Samples were cultured on Sabouraud dextrose agar, Czapek Dox agar, and nutrient agar media and broth. The selected colonies were isolated. Biochemical tests for identification were conducted. The yeast and bacteria contaminants were identified by morphological characteristics and biochemical reactions. The yeast isolated and identified from Gyogon alcohol distillery was Sacchacromyces cerevisiae. The bacteria contaminants isolated and identified were Aeromonas sp. and Pseudomonas sp.

Effects of Bacillus subtilis natto and Different Components in Culture on Rumen Fermentation and Rumen Functional Bacteria In Vitro.

Science.gov (United States)

Sun, Peng; Li, Jinan; Bu, Dengpan; Nan, Xuemei; Du, Hong

2016-05-01

This study was to investigate the effects of live or autoclaved Bacillus subtilis natto, their fermented products and media on rumen fermentation and rumen functional bacteria in vitro. Rumen fluid from three multiparous lactating Holstein cows was combined and transferred into serum bottles after diluted. Fifteen serum bottles were divided into five treatments, which were designed as following: CTR (the fermentation of 0.5 g TMR and ruminal fluids from dairy cows), LBS (CTR plus a minimum of 10(11) cfu live Bacillus subtilis natto), ABS (CTR plus a minimum of 10(11) cfu autoclaved Bacillus subtilis natto), BSC (CTR plus 1 ml Bacillus subtilis natto fermentation products without bacteria), and BSM (CTR plus 1 ml liquid fermentation medium). When separated from the culture, live Bacillus subtilis natto individually increased the concentrations of ammonia-N (P Bacillus subtilis natto has the similar function with the live bacteria except for the ratio of acetate and propionate. Except B. fibrisolvens, live or autoclaved Bacillus subtilis natto did not influence or decreased the 16S rRNA gene quantification of the detected bacteria. BSC and BSM altered the relative expression of certain functional bacteria in the rumen. These results indicated that it was Bacillus subtilis natto thalli that played the important role in promoting rumen fermentation when applied as a probiotic in dairy ration.

Exploratory analysis for the optimization of culture media for Bacillus thuringiensis fermentation

Directory of Open Access Journals (Sweden)

Jenny M. Escobar

2004-07-01

Full Text Available Agrichemical involve health risks for producers and consumers; they can also affect beneficial insects, birds, fish and mammals. Bacillus thuringiensis-based biopesticides specific for insect plagues are available, which, represent an alternative to traditional chemically-based products. Culture media design is an impor-tant factor in the production of biopesticides based on Bacillus thuringiensis. The media have to be economi-cal and they must contain all the nutrition factors required by the bacteria. The yield of active ingredient, comprising the toxin-containing crystal protein and bacterial spores, must be high and with adequate toxi-city to formulate the biopesticide. In this work we studied different culture media and optimised a promi-sing culture medium for B. thuringiensis fermentation to obtain an active ingredient for use as raw material in manufacturing a biopesticide. The final concentration of active ingredient was 15 to 16 g/L and the raw material cost around US $0,30/kg product. Calculations for the experimental phase were done using the response surface technique in a central composite design (CCD, the optimisation phase used Derringer and Suich (1980 method for dual response. Key words: Biopesticides, culture media, surface response, dual response, contour plots, central composite design.

The microbial diversity of traditional spontaneously fermented lambic beer.

Science.gov (United States)

Spitaels, Freek; Wieme, Anneleen D; Janssens, Maarten; Aerts, Maarten; Daniel, Heide-Marie; Van Landschoot, Anita; De Vuyst, Luc; Vandamme, Peter

2014-01-01

Lambic sour beers are the products of a spontaneous fermentation that lasts for one to three years before bottling. The present study determined the microbiota involved in the fermentation of lambic beers by sampling two fermentation batches during two years in the most traditional lambic brewery of Belgium, using culture-dependent and culture-independent methods. From 14 samples per fermentation, over 2000 bacterial and yeast isolates were obtained and identified. Although minor variations in the microbiota between casks and batches and a considerable species diversity were found, a characteristic microbial succession was identified. This succession started with a dominance of Enterobacteriaceae in the first month, which were replaced at 2 months by Pediococcus damnosus and Saccharomyces spp., the latter being replaced by Dekkera bruxellensis at 6 months fermentation duration.

The microbial diversity of traditional spontaneously fermented lambic beer.

Directory of Open Access Journals (Sweden)

Freek Spitaels

Full Text Available Lambic sour beers are the products of a spontaneous fermentation that lasts for one to three years before bottling. The present study determined the microbiota involved in the fermentation of lambic beers by sampling two fermentation batches during two years in the most traditional lambic brewery of Belgium, using culture-dependent and culture-independent methods. From 14 samples per fermentation, over 2000 bacterial and yeast isolates were obtained and identified. Although minor variations in the microbiota between casks and batches and a considerable species diversity were found, a characteristic microbial succession was identified. This succession started with a dominance of Enterobacteriaceae in the first month, which were replaced at 2 months by Pediococcus damnosus and Saccharomyces spp., the latter being replaced by Dekkera bruxellensis at 6 months fermentation duration.

Butanol production from wheat straw by simultaneous saccharification and fermentation using Clostridium beijerinckii: Part II-Fed-batch fermentation

International Nuclear Information System (INIS)

Qureshi, Nasib; Saha, Badal C.; Cotta, Michael A.

2008-01-01

In these studies, Clostridium beijerinckii P260 was used to produce butanol (acetone-butanol-ethanol, or ABE) from wheat straw (WS) hydrolysate in a fed-batch reactor. It has been demonstrated that simultaneous hydrolysis of WS to achieve 100% hydrolysis to simple sugars (to the extent achievable under present conditions) and fermentation to butanol is possible. In addition to WS, the reactor was fed with a sugar solution containing glucose, xylose, arabinose, galactose, and mannose. The culture utilized all of the above sugars. It was noticed that near the end of fermentation (286-533 h), the culture had difficulties utilizing xylose. As a result of supplemental sugar feed to the reactor, ABE productivity was improved by 16% as compared with previous studies. In our previous experiment on simultaneous saccharification of WS and fermentation to butanol, a productivity of 0.31 g L -1 h -1 was observed, while in the present studies a productivity of 0.36 g L -1 h -1 was observed. It should be noted that a productivity of 0.77 g L -1 h -1 was observed when the culture was highly active. The fed-batch fermentation was operated for 533 h. It should be noted that C. beijerinckii P260 can be used to produce butanol from WS in integrated fermentations

Use of continuous lactose fermentation for ethanol production by Kluveromyces marxianus for verification and extension of a biochemically structured model

DEFF Research Database (Denmark)

Sansonetti, S.; Hobley, Timothy John; Curcio, S.

2013-01-01

A biochemically structured model has been developed to describe the continuous fermentation of lactose to ethanol by Kluveromyces marxianus and allowed metabolic coefficients to be determined. Anaerobic lactose-limited chemostat fermentations at different dilution rates (0.02 – 0.35 h-1) were...... performed. Species specific rates of consumption/formation, as well as yield coefficients were determined. Ethanol yield (0.655 C-mol ethanol*C-mol lactose-1) was as high as 98 % of theoretical. The modeling procedure allowed calculation of maintenance coefficients for lactose consumption and ethanol...

STATE ESTIMATION IN ALCOHOLIC CONTINUOUS FERMENTATION OF ZYMOMONAS MOBILIS USING RECURSIVE BAYESIAN FILTERING: A SIMULATION APPROACH

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Olga Lucia Quintero

2008-05-01

Full Text Available This work presents a state estimator for a continuous bioprocess. To this aim, the Non Linear Filtering theory based on the recursive application of Bayes rule and Monte Carlo techniques is used. Recursive Bayesian Filters Sampling Importance Resampling (SIR is employed, including different kinds of resampling. Generally, bio-processes have strong non-linear and non-Gaussian characteristics, and this tool becomes attractive. The estimator behavior and performance are illustrated with the continuous process of alcoholic fermentation of Zymomonas mobilis. Not too many applications with this tool have been reported in the biotechnological area.

Isolation and characterization of halophilic lactic acid bacteria acting as a starter culture for sauce fermentation of the red alga Nori (Porphyra yezoensis).

Science.gov (United States)

Uchida, M; Miyoshi, T; Yoshida, G; Niwa, K; Mori, M; Wakabayashi, H

2014-06-01

A screening test was conducted for environmental samples to isolate halophilic lactic acid bacteria (HLAB) that can act as a starter in a Nori (Porphyra yezoensis)-sauce culture. After 9 months of incubation of enrichment cultures added with 25 kinds of environmental samples, growth of HLAB-like microorganisms was observed in six cultures salted at a 15% w/w level, including culture samples originally from mesopelagic water taken from 321 m-depth and from mountain snow taken at 2450 m-height. Ten strains were isolated and characterized as Tetragenococcus halophilus based on sequence analysis of the 16S rRNA gene. The isolates were inoculated into a newly prepared Nori-sauce culture and were confirmed to be able to act as a starter culture while three reference strains of T. halophilus obtained from a culture collection could not grow in the same culture. Halophilic lactic acid bacteria strains that can make growth in a highly salted Nori-sauce culture were isolated from environmental samples for the first time. All the isolates were identified as T. halophilus. The isolated strains are expected to be utilized as a starter culture for manufacturing fermented seaweed-sauce, which will be the first fermented food products obtained from algae. © 2014 The Society for Applied Microbiology.

Potassium metabisulphite as a potential biocide against Dekkera bruxellensis in fuel ethanol fermentations.

Science.gov (United States)

Bassi, A P G; Paraluppi, A L; Reis, V R; Ceccato-Antonini, S R

2015-03-01

Dekkera bruxellensis is an important contaminant yeast of fuel ethanol fermentations in Brazil, whose system applies cell repitching between the fermentative cycles. This work evaluated the addition of potassium metabisulphite (PMB) on yeast growth and fermentative yields in pure and co-cultures of Saccharomyces cerevisiae and D. bruxellensis in two situations: addition to the acidic solution in which the cells are treated between the fermentative cycles or to the fermentation medium. In the range of 200-400 mg l(-1) , PMB was effective to control the growth of D. bruxellensis depending on the culture medium and strain. When added to the acidic solution (250 mg l(-1) ), a significant effect was observed in mixed cultures, because the inactivation of SO2 by S. cerevisiae most likely protected D. bruxellensis from being damaged by PMB. The physiological response of S. cerevisiae to the presence of PMB may explain the significant decrease in alcohol production. When added to the fermentation medium, PMB resulted in the control but not the death of D. bruxellensis, with less intensive effect on the fermentative efficiency. In co-culture with the addition of PMB, the fermentative efficiency was significantly lower than in the absence of PMB. This study is the first to evaluate the action of potassium metabisulphite to control the growth of Dekkera bruxellensis in the fermentation process for fuel alcohol production. As near as possible of industrial conditions, the study simulates the addition of that substance in different points in the fermentation process, verifying in which situation the effects over the starter yeast and alcohol yield are minimal and over D. bruxellensis are maximal. Co-culture fermentations were carried out in cell-recycled batch system. The feasibility of using this substance for this specific fermentation is discussed in light of the possible biological and chemical interactions. © 2014 The Society for Applied Microbiology.

Enriched cultures of lactic acid bacteria from selected Zimbabwean fermented food and medicinal products with potential as therapy or prophylaxis against yeast infections

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Alec Chabwinja

2017-10-01

Full Text Available Objective: To investigate the antifungal activity of crude cultures of putative strains of lactic acid bacteria (LAB from a selection of Zimbabwean traditional and commercial food/ medicinal products against yeasts (strains of environmental isolates of Candida albicans and Rhodotorula spp.. Methods: Cultures of putative LAB from our selection of fermented products were enriched in de Man, Rogosa and Sharpe and isolated on de Man, Rogosa and Sharpe agar. Results: The crude microbial cultures from the products that showed high antifungal activities (zone of inhibition, mm were as follows: supernatant-free microbial pellet (SFMP from an extract of Melia azedarach leaves [(27.0 ± 2.5 mm] > cell-free culture supernatants (CFCS from Maaz Dairy sour milk and Mnandi sour milk [approximately (26.0 ± 1.8/2.5 mm] > CFCS and SFMP from Amansi hodzeko [(25.0 ± 1.5 mm] > CFCS from Parinari curatellifolia fruit [(24.0 ± 1.5 mm], SFMP from Parinari curatellifolia fruit [(24.0 ± 1.4 mm] and SFMP from mahewu [(20.0 ± 1.5 mm]. These cultures also showed high tolerance to acidic conditions (pH 4.0 and pH 5.0. However, culture from WAYA LGG (shown elsewhere to harbour antimicrobial activities showed no antifungal activity. The LAB could have inhibited yeasts by either competitive exclusion or the release of antimicrobial metabolites. Conclusions: Our cultures of LAB from a selection of Zimbabwean fermented products, especially Ziziphus mauritiana and fermented milk products have great potential for use as antifungal probiotics against yeast infections. Studies are ongoing to determine the exact mechanisms that are employed by the putative LAB to inhibit Candida albicans.

Lactic acid production from potato peel waste by anaerobic sequencing batch fermentation using undefined mixed culture.

Science.gov (United States)

Liang, Shaobo; McDonald, Armando G; Coats, Erik R

2015-11-01

Lactic acid (LA) is a necessary industrial feedstock for producing the bioplastic, polylactic acid (PLA), which is currently produced by pure culture fermentation of food carbohydrates. This work presents an alternative to produce LA from potato peel waste (PPW) by anaerobic fermentation in a sequencing batch reactor (SBR) inoculated with undefined mixed culture from a municipal wastewater treatment plant. A statistical design of experiments approach was employed using set of 0.8L SBRs using gelatinized PPW at a solids content range from 30 to 50 g L(-1), solids retention time of 2-4 days for yield and productivity optimization. The maximum LA production yield of 0.25 g g(-1) PPW and highest productivity of 125 mg g(-1) d(-1) were achieved. A scale-up SBR trial using neat gelatinized PPW (at 80 g L(-1) solids content) at the 3 L scale was employed and the highest LA yield of 0.14 g g(-1) PPW and a productivity of 138 mg g(-1) d(-1) were achieved with a 1 d SRT. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of Plant Secondary Metabolites on Methane Production and Fermentation Parameters in In vitro Ruminal Cultures

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Mihaela Giuburunca

2014-10-01

Full Text Available Enteric fermentation process is of concern worldwide for its contribution to global warming. It is known that ruminant animals, due to natural fermentation process contribute substantially to the increase in methane production. Methanogenesis process represents besides its contribution to greenhouse gases emissions an energy loss to the animal. To reduce ruminal methane productions in an ecologically and sustainable way, many attempts have been initiated, such as: uses of chemicals additives or ionophore antibiotics, defaunation process or immunization against ruminal methanogenesis. In the last years, a new strategy has been evaluated whether plant secondary metabolites can be used as natural additives to reduce ruminal methane emissions. The present study has been conducted to investigate the effects of trans-cinnamic, caffeic, p-coumaric acids and catechin hydrate, four plant secondary metabolites (PSMs on methane production and fermentation in in vitro ruminal cultures. The four PSMs were added anaerobically in a 6 mM concentration to 100 ml serum bottles containing 500 mg grass hay as a substrate, 10 ml rumen fluid collected from a fistulated sheep before morning feeding and 40 ml 141 DSM culture medium. The bottles were incubated at 39 ̊C. After 24 h, the following variables were measured: total gas volume, pH, methane and volatile fatty acids (VFAs production. The results showed that caffeic (p = 0.058 and p-coumaric (p = 0.052 acids tended to decrease methane production in comparison to control but the decrease was not statistic significantly at α= 0.05. The other two PSMs had no significant effect on methane production. Addition of PSMs did not affected the total gas volume, the pH and VFAs profile (P>0.05 in relation to the control (no PSM added. In conclusion, caffeic and p-coumaric acids in 6 mM concentration showed some promising effects for decreasing ruminal methane emissions without affecting ruminal fermentation parameters but

CONTROL BASED ON NUMERICAL METHODS AND RECURSIVE BAYESIAN ESTIMATION IN A CONTINUOUS ALCOHOLIC FERMENTATION PROCESS

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Olga L. Quintero

Full Text Available Biotechnological processes represent a challenge in the control field, due to their high nonlinearity. In particular, continuous alcoholic fermentation from Zymomonas mobilis (Z.m presents a significant challenge. This bioprocess has high ethanol performance, but it exhibits an oscillatory behavior in process variables due to the influence of inhibition dynamics (rate of ethanol concentration over biomass, substrate, and product concentrations. In this work a new solution for control of biotechnological variables in the fermentation process is proposed, based on numerical methods and linear algebra. In addition, an improvement to a previously reported state estimator, based on particle filtering techniques, is used in the control loop. The feasibility estimator and its performance are demonstrated in the proposed control loop. This methodology makes it possible to develop a controller design through the use of dynamic analysis with a tested biomass estimator in Z.m and without the use of complex calculations.

Solid substrate fermentation

Energy Technology Data Exchange (ETDEWEB)

Tengerdy, R P

1985-04-01

Solid Substrate Fermentation (SSF) describes the microbiological tranformation of biological materials in their natural state, in contrast with liquid or submerged fermentations which are carried out in dilute solutions or slurries. The most important industrial microorganisms used in SSF are filamentous fungi and the critical factors in their growth are the control of the moisture level and the temperature. Traditionally, most SSFs are conducted in shallow trays (so that heat build up is avoided) and stacked in a moist chamber, however, the modern SSF should be able to mix large amounts of substrate for a uniform fermentation, maximum automization scale-up of the process, continuous operation and fermentation control and a promising new design is the Helical screw fermenter. At the present time SSF is used in the production of foods (e.g. mushrooms and oriental foods) in municipal, agricultural and industrial solid waste disposal and in the production of enzymes and speciality chemicals but it does not seem likely that it will replace prevalent liquid fermentation technologies. 29 references.

The renaissance of continuous culture in the post-genomics age.

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Bull, Alan T

2010-10-01

The development of continuous culture techniques 60 years ago and the subsequent formulation of theory and the diversification of experimental systems revolutionised microbiology and heralded a unique period of innovative research. Then, progressively, molecular biology and thence genomics and related high-information-density omics technologies took centre stage and microbial growth physiology in general faded from educational programmes and research funding priorities alike. However, there has been a gathering appreciation over the past decade that if the claims of systems biology are going to be realised, they will have to be based on rigorously controlled and reproducible microbial and cell growth platforms. This revival of continuous culture will be long lasting because its recognition as the growth system of choice is firmly established. The purpose of this review, therefore, is to remind microbiologists, particularly those new to continuous culture approaches, of the legacy of what I call the first age of continuous culture, and to explore a selection of researches that are using these techniques in this post-genomics age. The review looks at the impact of continuous culture across a comprehensive range of microbiological research and development. The ability to establish (quasi-) steady state conditions is a frequently stated advantage of continuous cultures thereby allowing environmental parameters to be manipulated without causing concomitant changes in the specific growth rate. However, the use of continuous cultures also enables the critical study of specified transition states and chemical, physical or biological perturbations. Such dynamic analyses enhance our understanding of microbial ecology and microbial pathology for example, and offer a wider scope for innovative drug discovery; they also can inform the optimization of batch and fed-batch operations that are characterized by sequential transitions states.

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

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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.

Comparison of Different Strategies for Selection/Adaptation of Mixed Microbial Cultures Able to Ferment Crude Glycerol Derived from Second-Generation Biodiesel

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C. Varrone

2015-01-01

Full Text Available Objective of this study was the selection and adaptation of mixed microbial cultures (MMCs, able to ferment crude glycerol generated from animal fat-based biodiesel and produce building-blocks and green chemicals. Various adaptation strategies have been investigated for the enrichment of suitable and stable MMC, trying to overcome inhibition problems and enhance substrate degradation efficiency, as well as generation of soluble fermentation products. Repeated transfers in small batches and fed-batch conditions have been applied, comparing the use of different inoculum, growth media, and Kinetic Control. The adaptation of activated sludge inoculum was performed successfully and continued unhindered for several months. The best results showed a substrate degradation efficiency of almost 100% (about 10 g/L glycerol in 21 h and different dominant metabolic products were obtained, depending on the selection strategy (mainly 1,3-propanediol, ethanol, or butyrate. On the other hand, anaerobic sludge exhibited inactivation after a few transfers. To circumvent this problem, fed-batch mode was used as an alternative adaptation strategy, which led to effective substrate degradation and high 1,3-propanediol and butyrate production. Changes in microbial composition were monitored by means of Next Generation Sequencing, revealing a dominance of glycerol consuming species, such as Clostridium, Klebsiella, and Escherichia.

Comparison of Different Strategies for Selection/Adaptation of Mixed Microbial Cultures Able to Ferment Crude Glycerol Derived from Second-Generation Biodiesel.

Science.gov (United States)

Varrone, C; Heggeset, T M B; Le, S B; Haugen, T; Markussen, S; Skiadas, I V; Gavala, H N

2015-01-01

Objective of this study was the selection and adaptation of mixed microbial cultures (MMCs), able to ferment crude glycerol generated from animal fat-based biodiesel and produce building-blocks and green chemicals. Various adaptation strategies have been investigated for the enrichment of suitable and stable MMC, trying to overcome inhibition problems and enhance substrate degradation efficiency, as well as generation of soluble fermentation products. Repeated transfers in small batches and fed-batch conditions have been applied, comparing the use of different inoculum, growth media, and Kinetic Control. The adaptation of activated sludge inoculum was performed successfully and continued unhindered for several months. The best results showed a substrate degradation efficiency of almost 100% (about 10 g/L glycerol in 21 h) and different dominant metabolic products were obtained, depending on the selection strategy (mainly 1,3-propanediol, ethanol, or butyrate). On the other hand, anaerobic sludge exhibited inactivation after a few transfers. To circumvent this problem, fed-batch mode was used as an alternative adaptation strategy, which led to effective substrate degradation and high 1,3-propanediol and butyrate production. Changes in microbial composition were monitored by means of Next Generation Sequencing, revealing a dominance of glycerol consuming species, such as Clostridium, Klebsiella, and Escherichia.

Comparison of Different Strategies for Selection/Adaptation of Mixed Microbial Cultures Able to Ferment Crude Glycerol Derived from Second-Generation Biodiesel

DEFF Research Database (Denmark)

Varrone, Cristiano; Heggeset, T. M. B.; Le, S. B.

2015-01-01

Objective of this study was the selection and adaptation of mixed microbial cultures (MMCs), able to ferment crude glycerol generated from animal fat-based biodiesel and produce building-blocks and green chemicals. Various adaptation strategies have been investigated for the enrichment of suitable...... Control. The adaptation of activated sludge inoculum was performed successfully and continued unhindered for several months. The best results showed a substrate degradation efficiency of almost 100% (about 10 g/L glycerol in 21 h) and different dominant metabolic products were obtained, depending...... on the selection strategy (mainly 1,3-propanediol, ethanol, or butyrate). On the other hand, anaerobic sludge exhibited inactivation after a few transfers. To circumvent this problem, fed-batch mode was used as an alternative adaptation strategy, which led to effective substrate degradation and high 1...

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

Science.gov (United States)

Yamaoka, Chizuru; Kurita, Osamu; Kubo, Tomoko

2014-12-01

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

Effect of lactic acid bacteria starter culture fermentation of cassava ...

African Journals Online (AJOL)

SERVER

2007-08-20

Aug 20, 2007 ... of cassava on chemical and sensory characteristics of fufu flour ... cassava fufu flour has the highest protein content; this shows the influence of fermentation in .... 24, 48, 72, and 96 h, during the natural fermentation of cassava ...

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

Science.gov (United States)

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.

Fermentation performance optimization in an ectopic fermentation system.

Science.gov (United States)

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.

Effectiveness of Aspergillus oryzae fermentation culture to improve digestion of fibrous feeds

Directory of Open Access Journals (Sweden)

Darwinsyah Lubis

2002-06-01

Full Text Available Studies regarding the use of living microorganisms as supplement have been done in the last two decades to improve digestion process in the rumen. Many factors affect the use of the supplement, such as ration composition and physiological status of the animals. Materials used in this experiment are Aspergillus oryzae (AO derived from ‘tauco’ (salty fermented soybean and soybean sauce processing factories located in Bogor, Cianjur, and Sukabumi districts (15 sources, and also AO culture collections of the Indonesian Res. Inst. for Anim. Prod. (2 strains and one strain from Indonesian Res. Inst. for Vet. Sci. in Bogor. The fungus was first isolated in potato dextrose agar (PDA, incubated at room temp. (26-300C for 5 days for purification. The AO from PDA then inoculated into cooked rice enriched with mineral mix, oven-dried (40-450C, then ground and kept in refrigerator as a stock culture for further use. To produce more AO (scaling-up, the culture is inoculated in two basal media, i.e. soybean meal and ‘onggok’ (tapioca processing waste enriched with mineral mix, dried and ground, then kept in refrigerator as A. oryzae fermentation culture (AOFC. Ground-dried King grass was used for in vitro digestion trials using sheep rumen fluid, which was not supplemented (control or supplemented with the AOFC (10% w/w from various sources. Three best AOFC (by origin were chosen and used for further digestion study. The study was run using 2 (media x 3 (AOFC origin factorial experiment based on a completely randomized design and Duncan’s MRT was applied to test differences among treatment means. Preliminary results indicated of the AOFC-SP66, -F172, and -CT4 used, the best AOFC was SP66, as it increased (P<0.05 fiber (NDF digestion (10.5% better than the control. Total VFA productions were similar, but acetate content in the rumen fluid was lowered (P<0.05, while propionate and butyrate levels were alleviated (P<0.05 by the AOFC-SP66. Ammonia

Effects of fermentation by Saccharomyces cerevisiae and ...

African Journals Online (AJOL)

yassine

2013-02-13

Feb 13, 2013 ... Full Length Research Paper. Effect of Saccharomyces cerevisiae fermentation on the ... 2003). Besides, several alcoholic beverages such as wine or liqueurs are obtained from fruit juices fermented by Saccharomyces ..... (2003). Kinetics of pigment release from hairy root cultures of Beta vulgaris under the ...

Consolidated bioprocessing for butyric acid production from rice straw with undefined mixed culture

Directory of Open Access Journals (Sweden)

Binling Ai

2016-10-01

Full Text Available Lignocellulosic biomass is a renewable source with great potential for biofuels and bioproducts. However, the cost of cellulolytic enzymes limits the utilization of the low-cost bioresource. This study aimed to develop a consolidated bioprocessing without the need of supplementary cellulase for butyric acid production from lignocellulosic biomass. A stirred-tank reactor with a working volume of 21 L was constructed and operated in batch and semi-continuous fermentation modes with a cellulolytic butyrate-producing microbial community. The semi-continuous fermentation with intermittent discharging of the culture broth and replenishment with fresh medium achieved the highest butyric acid productivity of 2.69 g/(L•d. In semi-continuous operation mode, the butyric acid and total carboxylic acid concentrations of 16.2 and 28.9 g/L, respectively, were achieved. Over the 21-day fermentation period, their cumulative yields reached 1189 and 2048 g, respectively, corresponding to 41% and 74% of the maximum theoretical yields based on the amount of NaOH pretreated rice straw fed in. This study demonstrated that an undefined mixed culture-based consolidated bioprocessing for butyric acid production can completely eliminate the cost of supplementary cellulolytic enzymes.

Consolidated Bioprocessing for Butyric Acid Production from Rice Straw with Undefined Mixed Culture.

Science.gov (United States)

Ai, Binling; Chi, Xue; Meng, Jia; Sheng, Zhanwu; Zheng, Lili; Zheng, Xiaoyan; Li, Jianzheng

2016-01-01

Lignocellulosic biomass is a renewable source with great potential for biofuels and bioproducts. However, the cost of cellulolytic enzymes limits the utilization of the low-cost bioresource. This study aimed to develop a consolidated bioprocessing without the need of supplementary cellulase for butyric acid production from lignocellulosic biomass. A stirred-tank reactor with a working volume of 21 L was constructed and operated in batch and semi-continuous fermentation modes with a cellulolytic butyrate-producing microbial community. The semi-continuous fermentation with intermittent discharging of the culture broth and replenishment with fresh medium achieved the highest butyric acid productivity of 2.69 g/(L· d). In semi-continuous operation mode, the butyric acid and total carboxylic acid concentrations of 16.2 and 28.9 g/L, respectively, were achieved. Over the 21-day fermentation period, their cumulative yields reached 1189 and 2048 g, respectively, corresponding to 41 and 74% of the maximum theoretical yields based on the amount of NaOH pretreated rice straw fed in. This study demonstrated that an undefined mixed culture-based consolidated bioprocessing for butyric acid production can completely eliminate the cost of supplementary cellulolytic enzymes.

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

Science.gov (United States)

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.

Online monitoring of Mezcal fermentation based on redox potential measurements.

Science.gov (United States)

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.

Increase of methane formation by ethanol addition during continuous fermentation of biogas sludge.

Science.gov (United States)

Refai, Sarah; Wassmann, Kati; van Helmont, Sebastian; Berger, Stefanie; Deppenmeier, Uwe

2014-12-01

Very recently, it was shown that the addition of acetate or ethanol led to enhanced biogas formation rates during an observation period of 24 h. To determine if increased methane production rates due to ethanol addition can be maintained over longer time periods, continuous reactors filled with biogas sludge were developed which were fed with the same substrates as the full-scale reactor from which the sludge was derived. These reactors are well reflected conditions of a full-scale biogas plant during a period of 14 days. When the fermenters were pulsed with 50-100 mM ethanol, biomethanation increased by 50-150 %, depending on the composition of the biogas sludge. It was also possible to increase methane formation significantly when 10-20 mM pure ethanol or ethanolic solutions (e.g. beer) were added daily. In summary, the experiments revealed that "normal" methane production continued to take place, but ethanol led to production of additional methane.

Cell-to-cell contact and antimicrobial peptides play a combined role in the death of Lachanchea thermotolerans during mixed-culture alcoholic fermentation with Saccharomyces cerevisiae

DEFF Research Database (Denmark)

Kemsawasd, Varongsiri; Branco, Patrícia; Almeida, Maria Gabriela

2015-01-01

The roles of cell-to-cell contact and antimicrobial peptides in the early death of Lachanchea thermotolerans CBS2803 during anaerobic, mixed-culture fermentations with Saccharomyces cerevisiae S101 were investigated using a commercially available, double-compartment fermentation system separated ...

Effect of organic loading rate on dark fermentative hydrogen production in the continuous stirred tank reactor and continuous mixed immobilized sludge reactor from waste pastry hydrolysate.

Science.gov (United States)

Han, Wei; Hu, Yunyi; Li, Shiyi; Nie, Qiulin; Zhao, Hongting; Tang, Junhong

2016-12-01

Waste pastry (6%, w/v) was hydrolyzed by the produced glucoamylase and protease to obtain the glucose (19.8g/L) and free amino nitrogen (179mg/L) solution. Then, the effect of organic loading rate (OLR) (8-40kgCOD/(m 3 d)) on dark fermentative hydrogen production in the continuous stirred tank reactor (CSTR) and continuous mixed immobilized sludge reactor (CMISR) from waste pastry hydrolysate was investigated and compared. The maximum hydrogen production rate of CSTR (277.76mL/(hL)) and CMISR (320.2mL/(hL)) were achieved at OLR of 24kgCOD/(m 3 d) and 32kgCOD/(m 3 d), respectively. Carbon recovery ranged from 75.2-84.1% in the CSTR and CMISR with the balance assumed to be converted to biomass. One gram waste pastry could produce 0.33g (1.83mmol) glucose which could be further converted to 79.24mL (3.54mmol) hydrogen in the CMISR or 91.66mL (4.09mmol) hydrogen in the CSTR. This is the first study which reports dark fermentative hydrogen production from waste pastry. Copyright © 2016 Elsevier Ltd. All rights reserved.

Use of a continuous culture fermentation system to investigate the effect of GanedenBC30 (Bacillus coagulans GBI-30, 6086) supplementation on pathogen survival in the human gut microbiota.

Science.gov (United States)

Honda, Harue; Gibson, Glenn R; Farmer, Sean; Keller, David; McCartney, Anne L

2011-02-01

Single-stage continuous fermentation systems were employed to examine the effects of GanedenBC(30) supplementation on the human gastrointestinal microbiota in relation to pathogen challenge in vitro. Denaturing gradient gel electrophoresis analysis demonstrated that GanedenBC(30) supplementation modified the microbial profiles in the fermentation systems compared with controls, with profiles clustering according to treatment. Overall, GanedenBC(30) supplementation did not elicit major changes in bacterial population counts in vitro, although notably higher Bcoa191 counts were seen following probiotic supplementation (compared to the controls). Pathogen challenge did not elicit significant modification of the microbial counts in vitro, although notably higher Clit135 counts were seen in the control system post-Clostridium difficile challenge than in the corresponding GanedenBC(30)-supplemented systems. Sporulation appears to be associated with the anti-microbial activity of GanedenBC(30), suggesting that a bi-modal lifecycle of GanedenBC(30)in vivo may lead to anti-microbial activity in distal regions of the gastrointestinal tract. Copyright © 2011 Elsevier Ltd. All rights reserved.

Immigrants' continuing bonds with their native culture: assimilation analysis of three interviews.

Science.gov (United States)

Henry, Hani M; Stiles, William B; Biran, Mia W; Mosher, James K; Brinegar, Meredith Glick; Banerjee, Prashant

2009-06-01

Three case studies of immigrants to the US from China, Iraq, and Mexico were used to build a theory of acculturation in immigrants by integrating the continuing bonds model, which describes mourning in bereavement with the assimilation model, which describes psychological change in psychotherapy. Participants were interviewed about the loss of their native culture and their life in the US. One participant had not fully assimilated the loss of her native culture, but used her continuing bonds with her culture as a source of solace. Another participant used his continuing bonds with his culture as a source of solace, but these bonds had become a source of conflict with the host culture. The third participant had largely assimilated the loss of his native culture such that the voices of this culture were linked via meaning bridges with the voices of the host culture, and the continuing bonds were resources that helped him in his land of immigration.

Characterisation of lactic acid bacteria in spontaneously fermented camel milk and selection of strains for fermentation of camel milk

DEFF Research Database (Denmark)

Fugl, Angelina June Brandt; Berhe, Tesfemariam; Kiran, Anil

2017-01-01

The microbial communities in spontaneously fermented camel milk from Ethiopia were characterised through metagenomic 16S rRNA sequencing and lactic acid bacteria were isolated with the goal of selecting strains suitable as starter cultures. The fermented camel milk microbiota was dominated either...... by Lactobacillales or by Enterobacteriaceae, depending on incubation temperature and the provider of the milk. Strains of species with a potential use as starter cultures i.e., Lactococcus lactis, Lactobacillus plantarum, and Pediococcus acidilactici, were isolated. Fast acidifiers of camel milk have been isolated...

Bio-detoxification of phorbol esters and other anti-nutrients of Jatropha curcas seed cake by fungal cultures using solid-state fermentation.

Science.gov (United States)

Sharath, B S; Mohankumar, B V; Somashekar, D

2014-03-01

Jatropha seed cake, a byproduct after biodiesel extraction, has several anti-nutrients and toxins. Solid-state fermentation was carried out for the detoxification of the Jatropha seed cake (JSC) using different fungal cultures. The reduction in the anti-nutritional components such as tannins, phytates, saponins, lectin and protease inhibitor, and phorbol esters on 6th, 9th, and 12th day of fermentation was analyzed. The phorbol ester content in the unfermented JSC was 0.83 mg/g, and the maximum degradation of phorbol esters to the extent of 75% was observed in the case of JSC fermented with Cunninghamella echinulata CJS-90. The phytate degradation in the fermented JSC was in the range of 65-96%. There was a gradual reduction of saponin content in the JSC from 6th to 12th day, and the reduction of saponin was in the range of 55-99% after solid-state fermentation. The trypsin inhibitor activity and lectin were 1,680 trypsin inhibitor units (TIU) per gram and 0.32 hemagglutinating unit in the unfermented JSC, respectively. Trypsin inhibitor activity and lectin could not be detected in JSC after 12th day of solid-state fermentation. Tannins accounted for 0.53% in unfermented JSC, and there was a marginal increase of tannins after solid-state fermentation. The results indicate that biological detoxification could be a promising method to reduce anti-nutritional compounds and toxins in the JSC.

Continuous primary fermentation of beer with yeast immobilized on spent grains : the effect of operational conditions

OpenAIRE

Brányik, Tomáš; Vicente, A. A.; Cruz, José Machado; Teixeira, J. A.

2004-01-01

A one-stage continuous primary beer fermentation with immobilized brewing yeast was studied. The objective of the work was to optimize the operational conditions (aeration and temperature) in terms of volumetric productivity and organoleptic quality of green beer. The system consisted of an internal-loop airlift reactor and a carrier material prepared from spent grains (a brewing by-product). An industrial wort and yeast strain were used. The immobilized biomass (in amounts from two to sevenf...

Isolation of a lactic acid bacterium and yeast consortium from a fermented material of Ulva spp. (Chlorophyta).

Science.gov (United States)

Uchida, M; Murata, M

2004-01-01

Microbiota in a fermented culture of Ulva spp. was examined with the objective to characterize the type of fermentation and to obtain starter microbes for performing seaweed fermentation. Fermented Ulva spp. cultures which were obtained and transferred in a laboratory were examined for their microbiota. With phenotypic characterization and phylogenetic analysis based on rRNA gene nucleotide sequences, the predominant micro-organisms were identified as Lactobacillus brevis, Debaryomyces hanseni var. hansenii, and a Candida zeylanoides-related specimen, suggesting that the observed fermentation can be categorized to lactic acid and ethanol fermentation. Inoculating the individually cultured cell suspensions of the three kinds of micro-organisms with cellulase induced the fermentation in various kinds of seaweed. A microbial consortium composed of a lactic acid bacterium, L. brevis, and yeasts, D. hansenii and a C. zeylanoides-related specimen, were predominant in a fermented culture of Ulva spp. Lactic acid and ethanol fermentation could be induced in various kinds of seaweed by adding this microbial consortium along with cellulase. This is the first report of lactic acid and ethanol fermentation in seaweed, which is expected to provide a new material for food and dietary applications.

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

Science.gov (United States)

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

Yeast ecology of Kombucha fermentation.

Science.gov (United States)

Teoh, Ai Leng; Heard, Gillian; Cox, Julian

2004-09-01

Kombucha is a traditional fermentation of sweetened tea, involving a symbiosis of yeast species and acetic acid bacteria. Despite reports of different yeast species being associated with the fermentation, little is known of the quantitative ecology of yeasts in Kombucha. Using oxytetracycline-supplemented malt extract agar, yeasts were isolated from four commercially available Kombucha products and identified using conventional biochemical and physiological tests. During the fermentation of each of the four products, yeasts were enumerated from both the cellulosic pellicle and liquor of the Kombucha. The number and diversity of species varied between products, but included Brettanomyces bruxellensis, Candida stellata, Schizosaccharomyces pombe, Torulaspora delbrueckii and Zygosaccharomyces bailii. While these yeast species are known to occur in Kombucha, the enumeration of each species present throughout fermentation of each of the four Kombucha cultures demonstrated for the first time the dynamic nature of the yeast ecology. Kombucha fermentation is, in general, initiated by osmotolerant species, succeeded and ultimately dominated by acid-tolerant species.

Anaerobic thermophilic culture-system

Energy Technology Data Exchange (ETDEWEB)

Ljungdahl, L G; Wiegel, J K.W.

1981-04-14

A mixed culture system of Thermoanaerobacter ethanolicus and Clostridium thermocellum is employed for anaerobic, thermophilic ethanol fermentation of cellulose. By cellulase action, monosaccharides are formed which inhibit the growth of C. thermocellum, but are fermented by T. ethanolicus. Thus, at a regulated pH-value of 7.5, this mixed culture system of micro organisms results in a cellulose fermentation with a considerably higher ethanol yield.

Continuous hydrogen production from starch by fermentation

Energy Technology Data Exchange (ETDEWEB)

Yasuda, Keigo; Tanisho, Shigeharu [Yokohama National Univ. (Japan)

2010-07-01

This study was investigated the effect of hydraulic retention time (HRT) on hydrogen production rate, hydrogen yield and the production rate of volatile fatty acid. The experiment was performed in a continuous stirred tank reactor (CSTR) with a working volume of 1 L by using a Clostridium sp. The temperature of the CSTR was regulated 37 C. The pH was controlled 6.0 by the addition of 3 M of NaOH solution. Starch was used as the carbon source with the concentration of 30 g L{sup -1}. Hydrogen production rate increased from 0.9 L-H{sub 2} L-culture{sup -1} h{sup -1} to 3.2 L-H{sub 2} L-culture{sup -1} h{sup -1} along with the decrease of HRT from 9 h to 1.5 h. Hydrogen yield decreased at low HRT. The major volatile fatty acids are acetic acid, butyric acid and lactic acid. The production rates of acetic acid and butyric acid increased along with the decrease of HRT. On the other hand, the rate of lactic acid was low at high HRT while it increased at HRT 1.5 h. The increase of the production rate of lactic acid suggested one of the reasons that hydrogen yield decreased. (orig.)

Passion fruit by-product and fructooligosaccharides stimulate the growth and folate production by starter and probiotic cultures in fermented soymilk.

Science.gov (United States)

Albuquerque, Marcela Albuquerque Cavalcanti; Bedani, Raquel; LeBlanc, Jean Guy; Saad, Susana Marta Isay

2017-11-16

Two starter cultures (Streptococcus (St.) thermophilus ST-M6 and TA-40) and five probiotic strains (St. thermophilus TH-4, Lactobacillus (Lb.) acidophilus LA-5, Lb. rhamnosus LGG, Lb. fermentum PCC, and Lb. reuteri RC-14) were used to ferment different soymilk formulations supplemented with passion fruit by-product and/or fructo-oligosaccharides (FOS) with the aim of increasing folate concentrations. Growth and folate production of individual strains were evaluated and the results used to select co-cultures. Both St. thermophilus ST-M6 and TH-4 were the best folate producers and were able to increase the folate content of all soymilk formulations when used alone or in co-culture with lactobacilli strains, especially in the presence of both passion fruit by-product and FOS. Thus, passion fruit by-product and FOS could be used as dietary ingredients to stimulate the folate production by selected bacterial strains during the fermentation of soymilk. It was also shown that vitamin production by microorganisms is strain-dependent and may also be influenced by nutritional and environmental conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Health benefits of fermented foods: microbiota and beyond

NARCIS (Netherlands)

Marco, Maria L.; Heeney, Dustin; Binda, Sylvie; Cifelli, Christopher J.; Cotter, Paul D.; Foligné, Benoit; Gänzle, Michael; Kort, Remco; Pasin, Gonca; Pihlanto, Anne; Smid, Eddy J.; Hutkins, Robert

2017-01-01

Fermented foods and beverages were among the first processed food products consumed by humans. The production of foods such as yogurt and cultured milk, wine and beer, sauerkraut and kimchi, and fermented sausage were initially valued because of their improved shelf life, safety, and organoleptic

Health benefits of fermented foods : microbiota and beyond

NARCIS (Netherlands)

Marco, Maria L.; Heeney, Dustin; Binda, Sylvie; Cifelli, Christopher J.; Cotter, Paul D.; Foligné, Benoit; Gänzle, Michael; Kort, Remco; Pasin, Gonca; Pihlanto, Anne; Smid, Eddy J.; Hutkins, Robert

2017-01-01

Fermented foods and beverages were among the first processed food products consumed by humans. The production of foods such as yogurt and cultured milk, wine and beer, sauerkraut and kimchi, and fermented sausage were initially valued because of their improved shelf life, safety, and organoleptic

Metabolic and energetic aspects of the growth of Clostridium butyricum on glucose in chemostat culture.

Science.gov (United States)

Crabbendam, P M; Neijssel, O M; Tempest, D W

1985-09-01

The influence of a number of environmental parameters on the fermentation of glucose, and on the energetics of growth of Clostridium butyricum in chemostat culture, have been studied. With cultures that were continuously sparged with nitrogen gas, glucose was fermented primarily to acetate and butyrate with a fixed stoichiometry. Thus, irrespective of the growth rate, input glucose concentration, specific nutrient limitation and, within limits, the culture pH value, the acetate/butyrate molar ratio in the culture extracellular fluids was uniformly 0.74 +/- 0.07. Thus, the efficiency with which ATP was generated from glucose catabolism also was constant at 3.27 +/- 0.02 mol ATP/mol glucose fermented. However, the rate of glucose fermentation at a fixed growth rate, and hence the rate of ATP generation, varied markedly under some conditions, leading to changes in the Y glucose and YATP values. In general, glucose-sufficient cultures expressed lower yield values than a corresponding glucose-limited culture, and this was particularly marked with a potassium-limited culture. However, with a glucose-limited culture increasing the input glucose concentration above 40 g glucose X 1(-1) also led to a significant decrease in the yield values that could be partially reversed by increasing the sparging rate of the nitrogen gas. Finally glucose-limited cultures immediately expressed an increased rate of glucose fermentation when relieved of their growth limitation. Since the rate of cell synthesis did not increase instantaneously, again the yield values with respect to glucose consumed and ATP generated transiently decreased. Two conditions were found to effect a change in the fermentation pattern with a lowering of the acetate/butyrate molar ratio. First, a significant decrease in this ratio was observed when a glucose-limited culture was not sparged with nitrogen gas; and second, a substantial (and progressive) decrease was observed to follow addition of increasing amounts of

Enhancing acetone biosynthesis and acetone-butanol-ethanol fermentation performance by co-culturing Clostridium acetobutylicum/Saccharomyces cerevisiae integrated with exogenous acetate addition.

Science.gov (United States)

Luo, Hongzhen; Ge, Laibing; Zhang, Jingshu; Ding, Jian; Chen, Rui; Shi, Zhongping

2016-01-01

Acetone is the major by-product in ABE fermentations, most researches focused on increasing butanol/acetone ratio by decreasing acetone biosynthesis. However, economics of ABE fermentation industry strongly relies on evaluating acetone as a valuable platform chemical. Therefore, a novel ABE fermentation strategy focusing on bio-acetone production by co-culturing Clostridium acetobutylicum/Saccharomyces cerevisiae with exogenous acetate addition was proposed. Experimental and theoretical analysis revealed the strategy could, enhance C. acetobutylicum survival oriented amino acids assimilation in the cells; control NADH regeneration rate at moderately lower level to enhance acetone synthesis but without sacrificing butanol production; enhance the utilization ability of C. acetobutylicum on glucose and direct most of extra consumed glucose into acetone/butanol synthesis routes. By implementing the strategy using synthetic or acetate fermentative supernatant, acetone concentrations increased to 8.27-8.55g/L from 5.86g/L of the control, while butanol concentrations also elevated to the higher levels of 13.91-14.23g/L from 11.63g/L simultaneously. Copyright © 2015 Elsevier Ltd. All rights reserved.

A novel gas separation integrated membrane bioreactor to evaluate the impact of self-generated biogas recycling on continuous hydrogen fermentation

International Nuclear Information System (INIS)

Bakonyi, Péter; Buitrón, Germán; Valdez-Vazquez, Idania; Nemestóthy, Nándor; Bélafi-Bakó, Katalin

2017-01-01

Highlights: • A Gas Separation Membrane Bioreactor was designed to improve H_2 production. • Headspace gas after enrichment by PDMS membranes was used for reactor sparging. • Stripping the bioreactor with a CO_2-enriched gas enhanced the H_2 fermentation. - Abstract: A Gas Separation Membrane Bioreactor (GSMBR) by integrating membrane technology with a continuous biohydrogen fermenter was designed. The feasibility of this novel configuration for the improvement of hydrogen production capacity was tested by stripping the fermentation liquor with CO_2- and H_2-enriched gases, obtained directly from the bioreactor headspace. The results indicated that sparging the bioreactor with the CO_2-concentrated fraction of the membrane separation unit (consisting of two PDMS modules) enhanced the steady-state H_2 productivity (8.9–9.2 L H_2/L-d) compared to the membrane-less control CSTR to be characterized with 6.96–7.35 L H_2/L-d values. On the other hand, purging with the H_2-rich gas strongly depressed the achievable productivity (2.7–3.03 L H_2/L-d). Microbial community structure and soluble metabolic products were monitored to assess the GSMBR behavior. The study demonstrated that stripping the bioH_2 fermenter with its own, self-generated atmosphere after adjusting its composition (to higher CO_2-content) can be a promising way to intensify dark fermentative H_2 evolution.

The availability of a lactose medium for tea fungus culture and Kombucha fermentation

Directory of Open Access Journals (Sweden)

Markov S.L.

2012-01-01

Full Text Available Kombucha is a traditional beverage that is prepared by fermenting sucrose-sweetened black tea. A medium is inoculated with a cellulose pellicle (popularly known as a “tea fungus” or fermentation brought from previous cultivation process. Our aim was to test the possibility of obtaining a Kombucha beverage using different concentration of lactose as an alternative source of C-atoms. A traditional medium sweetened with sucrose or without sugar was used as control. Without lactose-fermenting yeast strains in tea fungus, lactose is not an adequate alternative source of the C-atom for Kombucha fermentation because it is not possible to obtain Kombucha with an appropriate acidity during a seven-day fermentation. Compared with the traditional medium, fermentation is significantly slower with high differences in acid content. In unsweetened tea inoculated with the beverage obtained from a previous traditional process, Kombucha fermentation processes and produces a beverage without sugar and alcohol. [Projekat Ministarstva nauke Republike Srbije, br. TR 31044

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

Science.gov (United States)

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.

Improving wood hydrolyzate fermentation by using schizosaccharomycetes

Energy Technology Data Exchange (ETDEWEB)

Kalyuzhnyi, M Ya; Ustinova, V I; Petrushko, G I

1967-01-01

The development of Schizosaccharomycetes (I) in wood hydrolyzates is not observed when fermentation is carried out by the convetional batch process, evidently because of the highly inhibitory action of the medium. More recently, with the introduction of continuous fermentation of wood and other hydrolyzates, the occurrence of I has been frequently reported, and in some hydrolysis plants, I became predominant, eliminating the budding yeast strains. The phenomenon can be attributed to higher temperatures employed in continuous fermentation, and to a more favorable medium, as the hydrolyzate is diluted with spent fermentation liquor (the flow of fresh medium constitutes about 20% of the fermentation-vat volume). The I cells, when grown under favorable conditions, have a high fermenting power, adapt easily to the fermentation of galactose, and give higher yields of ethanol than the budding yeast. As observed at plants using I, however, the cells are sensitive to variations in the fermentation process, and are inactivated upon storage. This is usually attributed to their inability to store polysaccharides, and especially glycogen. An experimental study undertaken to determine conditions under which reserve polysaccharides accumulate in I cells showed that the important factor is the quality of the medium in which the cells are grown and the conditions of storage. In media enriched with spent fermentaion liquor or with cell autolyzate and purified from toxic components, considerable amounts of glycogen accumulate in the cells.

Traditional fermented food and beverages for improved livelihoods

OpenAIRE

Mejia, Danilo; Marshall, Elaine

2015-01-01

"This booklet is intended to heighten awareness about the potential of fermented foods and beverages as a viable enterprise that can contribute to small-scale farmers' income, building on, and in full respect of, important social and cultural factors. It also looks at how fermented food and beverages contribute to food security through preservation and improved nutritional quality. It highlights the opportunities and challenges associated with small-scale fermentation activities, as well as m...

Exploiting the potential of gas fermentation

DEFF Research Database (Denmark)

Redl, Stephanie Maria Anna; Diender, Martijn; Jensen, Torbjørn Ølshøj

2017-01-01

The use of gas fermentation for production of chemicals and fuels with lower environmental impact is a technology that is gaining increasing attention. Over 38 Gt of CO2 is annually being emitted from industrial processes, thereby contributing significantly to the concentration of greenhouse gases...... in the atmosphere. Together with the gasification of biomass and different waste streams, these gases have the potential for being utilized for production of chemicals through fermentation processes. Acetogens are among the most studied organisms capable of utilizing waste gases. Although engineering...... focus on the advantages of alternative fermentation scenarios, including thermophilic production strains, multi-stage fermentations, mixed cultures, as well as mixotrophy. Such processes have the potential to significantly broaden the product portfolio, increase the product concentrations and yields...

Modeling a one-stage continuous ethanol fermentation

Energy Technology Data Exchange (ETDEWEB)

Michalski, H; Wieczorek, A

1974-01-01

Kinetics of the fermentation process carried out with Saccharomyces cerevisiae hybrid G-67 on synthetic media at different initial concentrations of sugar and mixing speed have been determined. No significant effect of mixing (Reynolds No. 1915-7760) and initial sugar concentrations within 50 to 150 g/l was found on the biomass and final ethanol concentration or on the amount of sugar consumed. The optimum dilution rate was 0.10 to 0.20 h/sup -1/. Kinetic equations for sugar and ethanol concentration changes in the process are given.

Effects of different Pediococcus halophilus level and fermentation time on chemical properties of fermented anchovy paste “terasi ikan”

Science.gov (United States)

Lestari, S. D.; Herpandi; Simamora, G. R. R.

2017-04-01

The aim of this study was to investigate the Pediococcus halophilus addition on the chemical quality of terasi ikan (fermented anchovy paste) product. Two levels of bacterial concentration (106 CFU/mL and 109 CFU/mL) were used as a single starter culture for the fermentation process. Changes in chemical characteristics were observed at day 7, 14 and 21. No differences (p > 0.05) in moisture and protein content were found in the analysis of variance within terasi ikan samples. The decrease in reducing sugar and L-lysine HCl during the fermentation was attributed to the formation of Maillard Reaction Products (MRPs) which was manifested in dark brown color of the end products. The interaction between P. halophilus and terasi ikan microbiota as well as their enzymatic activities were considered to affect vitamin B synthesis and degradation of protein into amino acids and amines. These findings facilitate further investigations on using P. halophilus as constituent of mixed culture, instead of as a single culture for terasi industry in order to produce products of well-controlled quality and safety.

Scleroglucan: Fermentative Production, Downstream Processing and Applications

Directory of Open Access Journals (Sweden)

Shrikant A. Survase

2007-01-01

Full Text Available Exopolysaccharides produced by a variety of microorganisms find multifarious industrial applications in foods, pharmaceutical and other industries as emulsifiers, stabilizers, binders, gelling agents, lubricants, and thickening agents. One such exopolysaccharide is scleroglucan, produced by pure culture fermentation from filamentous fungi of genus Sclerotium. The review discusses the properties, fermentative production, downstream processing and applications of scleroglucan.

Organic loading rates affect composition of soil-derived bacterial communities during continuous, fermentative biohydrogen production

Energy Technology Data Exchange (ETDEWEB)

Luo, Yonghua; Bruns, Mary Ann [Department of Crop and Soil Sciences, The Pennsylvania State University, University Park, PA 16802 (United States); Zhang, Husen; Salerno, Michael; Logan, Bruce E. [Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA 16802 (United States)

2008-11-15

Bacterial community composition during steady-state, fermentative H{sub 2} production was compared across a range of organic loading rates (OLRs) of 0.5-19 g COD l{sup -1} h{sup -1} in a 2-l continuous flow reactor at 30 C. The varied OLRs were achieved with glucose concentrations of 2.5-10 g l{sup -1} and hydraulic retention times of 1-10 h. The synthetic wastewater feed was amended with L-cysteine and maintained at a pH of 5.5. For each run at a given glucose concentration, the reactor was inoculated with an aliquot of well-mixed agricultural topsoil that had been heat-treated to reduce numbers of vegetative cells. At OLRs less than 2 g COD l{sup -1} h{sup -1}, DNA sequences from ribosomal RNA intergenic spacer analysis profiles revealed more diverse and variable populations (Selenomonas, Enterobacter, and Clostridium spp.) than were observed above 2 g COD l{sup -1} h{sup -1} (Clostridium spp. only). An isolate, LYH1, was cultured from a reactor sample (10 g glucose l{sup -1} at a 10-h HRT) on medium containing L-cysteine. In confirming H{sub 2} production by LYH1 in liquid batch culture, lag periods for H{sub 2} production in the presence and absence of L-cysteine were 5 and 50 h, respectively. The 16S rRNA gene sequence of LYH1 indicated that the isolate was a Clostridium sp. affiliated with RNA subcluster Ic, with >99% similarity to Clostridium sp. FRB1. In fluorescent in situ hybridization tests, an oligonucleotide probe complementary to the 16S rRNA of LYH1 hybridized with 90% of cells observed at an OLR of 2 g COD h{sup -1}, compared to 26% of cells at an OLR of 0.5 g COD l{sup -1} h{sup -1}. An OLR of 2 g COD l{sup -1} h{sup -1} appeared to be a critical threshold above which clostridia were better able to outcompete Enterobacteriaceae and other organisms in the mixed soil inoculum. Our results are discussed in light of other biohydrogen studies employing pure cultures and mixed inocula. (author)

Fermentation process diagnosis using a mathematical model

Energy Technology Data Exchange (ETDEWEB)

Yerushalmi, L; Volesky, B; Votruba, J

1988-09-01

Intriguing physiology of a solvent-producing strain of Clostridium acetobutylicum led to the synthesis of a mathematical model of the acetone-butanol fermentation process. The model presented is capable of describing the process dynamics and the culture behavior during a standard and a substandard acetone-butanol fermentation. In addition to the process kinetic parameters, the model includes the culture physiological parameters, such as the cellular membrane permeability and the number of membrane sites for active transport of sugar. Computer process simulation studies for different culture conditions used the model, and quantitatively pointed out the importance of selected culture parameters that characterize the cell membrane behaviour and play an important role in the control of solvent synthesis by the cell. The theoretical predictions by the new model were confirmed by experimental determination of the cellular membrane permeability.

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

Science.gov (United States)

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

2011-08-10

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

Microchemostat - microbial continuous culture in a polymer-based, instrumented microbioreactor

DEFF Research Database (Denmark)

Zhang, Z.; Bocazzi, P.; Choi, H. G.

2006-01-01

-based microbioreactor system integrated with optical density (OD), pH, and dissolved oxygen (DO) real-time measurements for continuous cultivation of microbial cells. Escherichia coli (E. coli) cells are continuously cultured in a 150 mL, membrane-aerated, well-mixed microbioreactor fed by a pressure-driven flow......In a chemostat, microbial cells reach a steady state condition at which cell biomass production, substrates and the product concentrations remain constant. These features make continuous culture a unique and powerful tool for biological and physiological research. We present a polymer...

Impulsive control of a continuous-culture and flocculation harvest chemostat model

Science.gov (United States)

Zhang, Tongqian; Ma, Wanbiao; Meng, Xinzhu

2017-12-01

In this paper, a new mathematical model describing the process of continuous culture and harvest of microalgaes is proposed. By inputting medium and flocculant at two different fixed moments periodically, continuous culture and harvest of microalgaes is implemented. The mathematical analysis is conducted and the whole dynamics of model is investigated by using theory of impulsive differential equations. We find that the model has a microalgaes-extinction periodic solution and it is globally asymptotically stable when some certain threshold value is less than the unit. And the model is permanent when some certain threshold value is larger than the unit. Then, according to the threshold, the control strategies of continuous culture and harvest of microalgaes are discussed. The results show that continuous culture and harvest of microalgaes can be archived by adjusting suitable input time, input amount of medium or flocculant. Finally, some numerical simulations are carried out to verify the control strategy.

Design and Investigation of PolyFermS In Vitro Continuous Fermentation Models Inoculated with Immobilized Fecal Microbiota Mimicking the Elderly Colon.

Science.gov (United States)

Fehlbaum, Sophie; Chassard, Christophe; Haug, Martina C; Fourmestraux, Candice; Derrien, Muriel; Lacroix, Christophe

2015-01-01

In vitro gut modeling is a useful approach to investigate some factors and mechanisms of the gut microbiota independent of the effects of the host. This study tested the use of immobilized fecal microbiota to develop different designs of continuous colonic fermentation models mimicking elderly gut fermentation. Model 1 was a three-stage fermentation mimicking the proximal, transverse and distal colon. Models 2 and 3 were based on the new PolyFermS platform composed of an inoculum reactor seeded with immobilized fecal microbiota and used to continuously inoculate with the same microbiota different second-stage reactors mounted in parallel. The main gut bacterial groups, microbial diversity and metabolite production were monitored in effluents of all reactors using quantitative PCR, 16S rRNA gene 454-pyrosequencing, and HPLC, respectively. In all models, a diverse microbiota resembling the one tested in donor's fecal sample was established. Metabolic stability in inoculum reactors seeded with immobilized fecal microbiota was shown for operation times of up to 80 days. A high microbial and metabolic reproducibility was demonstrated for downstream control and experimental reactors of a PolyFermS model. The PolyFermS models tested here are particularly suited to investigate the effects of environmental factors, such as diet and drugs, in a controlled setting with the same microbiota source.

Design and Investigation of PolyFermS In Vitro Continuous Fermentation Models Inoculated with Immobilized Fecal Microbiota Mimicking the Elderly Colon.

Directory of Open Access Journals (Sweden)

Sophie Fehlbaum

Full Text Available In vitro gut modeling is a useful approach to investigate some factors and mechanisms of the gut microbiota independent of the effects of the host. This study tested the use of immobilized fecal microbiota to develop different designs of continuous colonic fermentation models mimicking elderly gut fermentation. Model 1 was a three-stage fermentation mimicking the proximal, transverse and distal colon. Models 2 and 3 were based on the new PolyFermS platform composed of an inoculum reactor seeded with immobilized fecal microbiota and used to continuously inoculate with the same microbiota different second-stage reactors mounted in parallel. The main gut bacterial groups, microbial diversity and metabolite production were monitored in effluents of all reactors using quantitative PCR, 16S rRNA gene 454-pyrosequencing, and HPLC, respectively. In all models, a diverse microbiota resembling the one tested in donor's fecal sample was established. Metabolic stability in inoculum reactors seeded with immobilized fecal microbiota was shown for operation times of up to 80 days. A high microbial and metabolic reproducibility was demonstrated for downstream control and experimental reactors of a PolyFermS model. The PolyFermS models tested here are particularly suited to investigate the effects of environmental factors, such as diet and drugs, in a controlled setting with the same microbiota source.

Statistical culture-based strategies to enhance chlamydospore production by Trichoderma harzianum SH2303 in liquid fermentation*

Science.gov (United States)

Li, Ya-qian; Song, Kai; Li, Ya-chai; Chen, Jie

2016-01-01

Trichoderma-based formulations are applied as commercial biocontrol agents for soil-borne plant pathogens. Chlamydospores are active propagules in Trichoderma spp., but their production is currently limited due to a lack of optimal liquid fermentation technology. In this study, we explored response surface methodologies for optimizing fermentation technology in Trichoderma SH2303. Our initial studies, using the Plackett-Burman design, identified cornmeal, glycerol, and initial pH levels as the most significant factors (P<0.05) for enhancing the production of chlamydospores. Subsequently, we applied the Box-Behnken design to study the interactions between, and optimal levels of, a number of factors in chlamydospore production. These statistically predicted results indicated that the highest number of chlamydospores (3.6×108 spores/ml) would be obtained under the following condition: corn flour 62.86 g/L, glycerol 7.54 ml/L, pH 4.17, and 6-d incubation in liquid fermentation. We validated these predicted values via three repeated experiments using the optimal culture and achieved maximum chlamydospores of 4.5×108 spores/ml, which approximately a 8-fold increase in the number of chlamydospores produced by T. harzianum SH2303 compared with that before optimization. These optimized values could help make chlamydospore production cost-efficient in the future development of novel biocontrol agents. PMID:27487807

Statistical culture-based strategies to enhance chlamydospore production by Trichoderma harzianum SH2303 in liquid fermentation.

Science.gov (United States)

Li, Ya-Qian; Song, Kai; Li, Ya-Chai; Chen, Jie

2016-08-01

Trichoderma-based formulations are applied as commercial biocontrol agents for soil-borne plant pathogens. Chlamydospores are active propagules in Trichoderma spp., but their production is currently limited due to a lack of optimal liquid fermentation technology. In this study, we explored response surface methodologies for optimizing fermentation technology in Trichoderma SH2303. Our initial studies, using the Plackett-Burman design, identified cornmeal, glycerol, and initial pH levels as the most significant factors (P<0.05) for enhancing the production of chlamydospores. Subsequently, we applied the Box-Behnken design to study the interactions between, and optimal levels of, a number of factors in chlamydospore production. These statistically predicted results indicated that the highest number of chlamydospores (3.6×10(8) spores/ml) would be obtained under the following condition: corn flour 62.86 g/L, glycerol 7.54 ml/L, pH 4.17, and 6-d incubation in liquid fermentation. We validated these predicted values via three repeated experiments using the optimal culture and achieved maximum chlamydospores of 4.5×10(8) spores/ml, which approximately a 8-fold increase in the number of chlamydospores produced by T. harzianum SH2303 compared with that before optimization. These optimized values could help make chlamydospore production cost-efficient in the future development of novel biocontrol agents.

Immobilization of Cells and Enzymes for Fermented Dairy or Meat Products

Science.gov (United States)

Champagne, Claude P.; Lee, Byong H.; Saucier, Linda

Historically, we can find fermented products in almost all cultural backgrounds around the world. Notably, there are many different milk or meat-based foods and this chapter will focus on them (Kosikowski 1982; Wood 1998). Cheese, yoghurt, sour cream, kefir, or cultured butter are probably the most common fermented dairy products, but many regional varieties exist (Farnworth 2004). Fermented meats are typically found as dry sausages (Lüke 1998). Yeasts are mostly involved in the manufacture of bread and alcoholic beverages, which are basically cereal- or fruit-based products. In fermented meat and milk, the main microorganisms used are the lactic acid bacteria (LAB). Yeast and molds are rather involved in ripening. Therefore, the LAB will constitute the main focus of this chapter.

Immunomodulatory properties of fermented soy and dairy milks prepared with lactic acid bacteria.

Science.gov (United States)

Wagar, L E; Champagne, C P; Buckley, N D; Raymond, Y; Green-Johnson, J M

2009-10-01

Fermented soy and dairy milk preparations provide a means for delivering lactic acid bacteria and their fermentation products into the diet. Our aims were to test immunomodulatory bioactivity of fermented soy beverage (SB) and dairy milk blend (MB) preparations on human intestinal epithelial cells (IEC) and to determine the impact of freezing medium on culture survival prior to bioactivity analyses. Fermented SB and MB were prepared using pure or mixed cultures of Streptococcus thermophilus ST5, Bifidobacterium longum R0175, and Lactobacillus helveticus R0052. Immunomodulatory bioactivity was assessed by testing selected SB and MB ferments on tumor necrosis factor alpha (TNFalpha)-treated IEC and measuring effects on Interleukin-8 (IL-8) production. Impact of timing of ferment administration relative to this pro-inflammatory challenge was investigated. The most pronounced reductions in IEC IL-8 production were observed when IEC were treated with either SB or MB ferment preparations prior to TNFalpha challenge. These results indicate that freezing-stable MB and SB ferments prepared with selected strains can modulate IEC IL-8 production in vitro, and suggest that yogurt-like fermented soy formulations could provide a functional food alternative to milk-based fermented products.

An action research study; cultural differences impact how manufacturing organizations receive continuous improvement

Science.gov (United States)

Kattman, Braden R.

National culture and organizational culture impact how continuous improvement methods are received, implemented and deployed by suppliers. Previous research emphasized the dominance of national culture over organizational culture. The countries studied included Poland, Mexico, China, Taiwan, South Korea, Estonia, India, Canada, the United States, the United Kingdom, and Japan. The research found that Canada was most receptive to continuous improvement, with China being the least receptive. The study found that organizational culture was more influential than national culture. Isomorphism and benchmarking is driving continuous-improvement language and methods to be more universally known within business. Business and management practices are taking precedence in driving change within organizations.

Continuous fermentative hydrogen production from coffee drink manufacturing wastewater by applying UASB reactor

Energy Technology Data Exchange (ETDEWEB)

Jung, Kyung-Won; Shin, Hang-Sik [Department of Civil and Environmental Engineering, KAIST, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, Dong-Hoon [Department of Civil and Environmental Engineering, University of Windsor, 401 Sunset Ave., Essex Hall, Windsor, Ontario (Canada)

2010-12-15

The feasibility of continuous H{sub 2} production from coffee drink manufacturing wastewater (CDMW) was tested in two different types of reactors: a completely-stirred tank reactor (CSTR) and an up-flow anaerobic sludge blanket reactor (UASBr). While the performance in CSTR was limited, it was significantly enhanced in UASBr. The maximum H{sub 2} yield of 1.29 mol H{sub 2}/mol hexose{sub added} was achieved at HRT of 6 h in UASBr operation. Non-hydrogenic, lactic acid was the dominant in CSTR, while butyric and caproic acids in UASBr. As caproic acid is generated by consuming acetic and butyric acids, all of which are related to H{sub 2} production, the presence of caproic acid in the broth also indicates H{sub 2} production, yielding 1.33 mol H{sub 2}/glucose. It was speculated that the enhanced performance in UASBr was attributed to the high concentration of biomass over 60,000 mg VSS/L in the blanket zone, which provided insufficient substrate for indigenous lactic acid bacteria (LAB) to survive. The abundance of LAB in CDMW was confirmed by natural fermentation of CDMW. That is without the addition of external inoculum, CDMW was mainly fermented into lactic acid under mesophilic condition. For the first time ever, H{sub 2} producing granules (HPG) with diameters of 2.1 mm were successfully formed by using actual waste as a substrate. (author)

Microbiological Characteristics of Trachanas, a Traditional Fermented Dairy Product from Cyprus

Directory of Open Access Journals (Sweden)

Despina Bozoudi

2017-01-01

Full Text Available The purpose of this study was to characterize the autochthonous microbiota of Cypriot Trachanas, a traditional fermented ewes’ milk product. For this reason, 12 samples of raw and fermented milk as well as natural starter culture were collected in order to count, isolate, and identify the main species present during Trachanas fermentation. In total, 198 colonies were retrieved and 163 were identified by sequencing analysis at species level. Lactic acid bacteria (LAB were the predominant group, followed by yeasts. Lactococcus, Lactobacillus, and Enterococcus were frequently isolated from raw milk, and Lactobacillus casei/paracasei predominated in the starter culture. Lactococcus lactis was isolated in high frequency (27.9% of the isolates at the beginning, while Lactobacillus spp. (20% and Saccharomyces unisporus (17.9% were isolated at the end of fermentation. After assessing their technological potential, selected strains could be used as starters to ferment milk for artisanal Trachanas production.

Fermentative Hydrogen Production from Combination of Tofu processing and anaerobic digester sludge wastes using a microbial consortium

International Nuclear Information System (INIS)

You-Kwan, O.; Mi-Sun, K.

2009-01-01

The combination of Tofu manufacturing waste and anaerobic digester sludge was studied for fermentative H 2 production in batch and continuous modes using a mixed culture originated from sewage. In order to increase the solubilization of organic substrates from Tofu waste, various pretreatments including heat-treatment, acid/alkali treatment, and sonication were examined alone or in combination with others. (Author)

Some probiotic characteristics of a fermented milk product based on microbiota of "Tibetan kefir grains" cultivated in Ukrainian household.

Science.gov (United States)

Kukhtyn, Mykola; Vichko, Olena; Horyuk, Yulia; Shved, Olga; Novikov, Volodymyr

2018-01-01

The article describes some probiotic properties of fermented product made of natural association of Tibetan kefir grains cultivated in Ukrainian household (UTKG); also, the effect of UTKG microbiota on the growth of pathogenic microbiota and sensitivity to antibiotics was studied. It was found that the test-cultures of oppurtunistic pathogens ( Staphylococcus aureus , Bacillus mesentericus , and Mycobacterium luteum ) were sensitive; bacteriostatic zone of the test-culture ranged from 21 to 25 mm, and highly sensitive ( Proteus vulgaris and Aspergillus niger ) b acteriostatic zone exceeded 25 mm to probiotic bacteria of fermented product. UTKG microbiota is also moderately sensitive to multiple antibiotics that allows defining the obtained fermented milk product as functional with therapeutic properties. During the study of the influence of different NaCl and bile concentrations on acid-activity of UTKG it was found that active acid formation occurred at the concentrations up to 4% NaCl in cultivation medium (boiled milk) and at 20% bile and 0.45% phenol. It proves microbial association to be capable of withstanding adverse gastrointestinal conditions and continue developing.

Fermentation of molasses-flour mashes by acetone-butanol bacteria

Energy Technology Data Exchange (ETDEWEB)

Chekasina, E V

1962-01-01

With Clostridium acetobutylicum used in a continuous fermentation, where the mash passes through 5 to 12 fermenters, sufficient conversion of starch to mono- and disaccharides will occur; the number of fermenters were chosen and mash changed so that fresh mash remains for 34 hours in the cycle. After a 29 hour fermentation average yields were: acetone 4.5, ethanol 3.0, butanol 7.5%.

Biohydrogen production from combined dark-photo fermentation under a high ammonia content in the dark fermentation effluent

Energy Technology Data Exchange (ETDEWEB)

Chen, Chun-Yen [National Cheng Kung Univ., Tainan, Taiwan (China). Dept. of Chemical Engineering; National Cheng Kung Univ., Tainan, Taiwan (China). Sustainable Environment Research Center; Lo, Yung-Chung; Yeh, Kuei-Ling [National Cheng Kung Univ., Tainan, Taiwan (China). Dept. of Chemical Engineering; Chang, Jo-Shu [National Cheng Kung Univ., Tainan, Taiwan (China). Dept. of Chemical Engineering; National Cheng Kung Univ., Tainan, Taiwan (China). Sustainable Environment Research Center; National Cheng Kung Univ., Tainan, Taiwan (China). Microalgae Biotechnology and Bioengineering Lab.

2010-07-01

Integrated dark and photo (two-stage) fermentation was employed to enhance the performance of H{sub 2} production. First, the continuous dark fermentation using indigenous Clostridium butyricum CGS5 was carried out at 12 h HRT and fed with sucrose at a concentration of 18750 mg/l. The overall H{sub 2} production rate and H{sub 2} yield were fairly stable with a mean value of 87.5 ml/l/h and 1.015 mol H{sub 2}/mol sucrose, respectively. In addition, a relatively high ammonia nitrogen content (574 mg/l) in the dark fermentation effluent was observed. The soluble metabolites from dark fermentation, consisting mainly of butyric, lactic and acetic acids, were directly used as the influent of continuous photo-H{sub 2} production process inoculated with Rhodopseudomonas palutris WP 3-5 under the condition of 35oC, 10000 lux irradiation, pH 7.0 and 48 h HRT. The maximum overall hydrogen production rate from photo fermentation was 16.4 ml H{sub 2}/l/h, and the utilization of the soluble metabolites could reach 90%. The maximum H{sub 2} yield dramatically increased from 1.015 mol H{sub 2}/mol sucrose (in dark fermentation only) to 6.04 mol H{sub 2}/mol sucrose in the combined dark and photo fermentation. Surprisingly, the operation strategy applied in this work was able to attain an average NH{sub 3}-N removal efficiency of 92%, implying that our photo-H{sub 2} production system has a higher NH{sub 3}-N tolerance, demonstrating its high applicability in an integrated dark-photo fermentation system. (orig.)

Industrial alcohol production via whey and grain fermentation

Energy Technology Data Exchange (ETDEWEB)

Friend, B A; Cunningham, M L; Shahani, K M

1982-01-01

Six strains of a trained lactose fermenting Kluyveromyces yeast were examined for their ability to utilise lactose in sweet-whey permeate. All strains of K. fragilis tested reduced the concentration of the 5.1% lactose, initially present in whey permeate, to 0.1-0.2% within 48h. Periodic adjustment to maintain the pH during fermentation did not alter the lactose utilisation. The fermentation efficiency of K. fragilis was then compared with that of a mixture of K. fragilis and the classical alcohol fermenter Saccharomyces cerevisiae to verify that no unfavourable interactions occurred in the mixed culture. There were no differences in lactose utilisation or ethanol production between the two groups; both produced approximately 2% ethanol within 24h. This represented approximately 80% of the alcohol which theoretically could be produced from the 5.1% lactose present in the permeate. Whey permeate was also incorporated into the classical grain fermentation by substitution for one-half the water normally added to produce the mash. Fermentation was nearly complete by 36h and alcohol levels ranged from 9.7% for the mixed culture to 9.4% for the K. fragilis and 9.3% for the S. cerevisiae. Since the whey provided significant levels of fermentable sugars, studies were also conducted in which undiluted whey permeate was substituted for all of the water in the mash and the amount of grain was reduced by 20%. At the end of 36h K. fragilis produced 10.9% alcohol and at 60 h of fermentation the level had reached 12.2%. When whole sweet-whey was used, similar levels of alcohol were produced. (Refs. 20).

Food fermentations: Microorganisms with technological beneficial use

DEFF Research Database (Denmark)

Bourdichon, François; Casaregola, Serge; Farrokh, Choreh

2012-01-01

Microbial food cultures have directly or indirectly come under various regulatory frameworks in the course of the last decades. Several of those regulatory frameworks put emphasis on “the history of use”, “traditional food”, or “general recognition of safety”. Authoritative lists of microorganism......, legumes, cereals, beverages, and vinegar). We have also reviewed and updated the taxonomy of the microorganisms used in food fermentations in order to bring the taxonomy in agreement with the current standing in nomenclature....... cultures in practical use. However, as the focus mainly was on commercially available dairy cultures, there was an unmet need for a list with a wider scope. We present an updated inventory of microorganisms used in food fermentations covering a wide range of food matrices (dairy, meat, fish, vegetables...

Process for the fermentative production of acetone, butanol and ethanol

Science.gov (United States)

Glassner, David A.; Jain, Mahendra K.; Datta, Rathin

1991-01-01

A process including multistage continuous fermentation followed by batch fermentation with carefully chosen temperatures for each fermentation step, combined with an asporogenic strain of C. acetobutylicum and a high carbohydrate substrate concentration yields extraordinarily high butanol and total solvents concentrations.

Acid protease and formation of multiple forms of glycoamylase in batch and continuous cultures of Aspergillus niger

DEFF Research Database (Denmark)

Aalbæk, Thomas; Reeslev, Morten; Jensen, Bo

2002-01-01

In order to identify factors responsible for production of multiple forms of glucoamylase (GA) by Aspergillus niger Bo-1, the fungus was cultured in both complex and defined media in pH-controlled batch fermenters and chemostats. At all culture conditions three forms of GA were produced...... degradation of the GA forms at low pH. It was concluded that the observed modifications of the extracellular profile of GA isoforms in A. niger Bo-1 are due to changes in pH and medium composition....

Starter cultures for cereal based foods.

Science.gov (United States)

Brandt, Markus J

2014-02-01

Fermented cereals play a significant role in human nutrition in all parts of the world where cereals grow. These fermentations are started spontaneously or there have been traditional techniques developed in order to keep starter cultures for these processes alive. With the growing impact of industrial microbiology during 20th century this traditional starter culture propagation was replaced often, especially in the dairy industry, by the use of pure, frozen or freeze-dried cultures grown on microbial media. In contrast to the production of ethanol from cereals, in sourdough a pasteurization step before inoculation is avoided due to gelatinization of starch and inactivation of endogenous enzymes. Therefore cultures must be competitive to the relatively high microbial load of the cereal raw materials and well adapted to the specific ecology determined by the kind of cereal and the process conditions. Less adapted cultures could be used, but then the process of back-slopping of cultures is limited. Although cereal fermentations take the biggest volume among fermented foods, only for sourdoughs commercial cultures are available. Copyright © 2013 Elsevier Ltd. All rights reserved.

Hypolipidemic effects of lactic acid bacteria fermented cereal in rats

Directory of Open Access Journals (Sweden)

Banjoko Immaculata

2012-12-01

Full Text Available Abstract Background The objectives of the present study were to investigate the efficacy of the mixed culture of Lactobacillus acidophilus (DSM 20242, Bifidobacterium bifidum (DSM 20082 and Lactobacillus helveticus (CK60 in the fermentation of maize and the evaluation of the effect of the fermented meal on the lipid profile of rats. Methods Rats were randomly assigned to 3 groups and each group placed on a Diet A (high fat diet into which a maize meal fermented with a mixed culture of Lb acidophilus (DSM 20242, B bifidum (DSM 20082 and Lb helveticus (CK 60 was incorporated, B (unfermented high fat diet or C (commercial rat chow respectively after the first group of 7 rats randomly selected were sacrificed to obtain the baseline data. Thereafter 7 rats each from the experimental and control groups were sacrificed weekly for 4 weeks and the plasma, erythrocytes, lipoproteins and organs of the rats were assessed for cholesterol, triglyceride and phospholipids. Results Our results revealed that the mixed culture of Lb acidophilus (DSM 20242, B bifidum (DSM 20082 and Lb helveticus (CK 60 were able to grow and ferment maize meal into ‘ogi’ of acceptable flavour. In addition to plasma and hepatic hypercholesterolemia and hypertriglyceridemia, phospholipidosis in plasma, as well as cholesterogenesis, triglyceride constipation and phospholipidosis in extra-hepatic tissues characterized the consumption of unfermented hyperlipidemic diets. However, feeding the animals with the fermented maize diet reversed the dyslipidemia. Conclusion The findings of this study indicate that consumption of mixed culture lactic acid bacteria (Lb acidophilus (DSM 20242, Bifidobacterium bifidum (DSM 20082 and Lb helveticus (CK 60 fermented food results in the inhibition of fat absorption. It also inhibits the activity of HMG CoA reductase. This inhibition may be by feedback inhibition or repression of the transcription of the gene encoding the enzyme via activation of the

A fermented meat model system for studies of microbial aroma formation

DEFF Research Database (Denmark)

Tjener, Karsten; Stahnke, Louise Heller; Andersen, L.

2003-01-01

A fermented meat model system was developed, by which microbial formation of volatiles could be examined The model was evaluated against dry, fermented sausages with respect to microbial growth, pH and volatile profiles. Fast and slowly acidified sausages and models were produced using the starte......H, microbial growth and volatile profiles was similar to sausage production. Based on these findings, the model system was considered valid for studies of aroma formation of meat cultures for fermented sausage.......A fermented meat model system was developed, by which microbial formation of volatiles could be examined The model was evaluated against dry, fermented sausages with respect to microbial growth, pH and volatile profiles. Fast and slowly acidified sausages and models were produced using the starter...... cultures Pediococcus pentosaceus and Staphylococcus xylosus. Volatiles were collected and analysed by dynamic headspace sampling and GC MS. The analysis was primarily focused on volatiles arising from amino acid degradation and a total of 24 compounds, of which 19 were quantified, were used...

Lactobacillus sakei: A Starter for Sausage Fermentation, a Protective Culture for Meat Products

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Monique Zagorec

2017-09-01

Full Text Available Among lactic acid bacteria of meat products, Lactobacillus sakei is certainly the most studied species due to its role in the fermentation of sausage and its prevalence during cold storage of raw meat products. Consequently, the physiology of this bacterium regarding functions involved in growth, survival, and metabolism during meat storage and processing are well known. This species exhibits a wide genomic diversity that can be observed when studying different strains and on which probably rely its multiple facets in meat products: starter, spoiler, or protective culture. The emerging exploration of the microbial ecology of meat products also revealed the multiplicity of bacterial interactions L. sakei has to face and their various consequences on microbial quality and safety at the end of storage.

Lactobacillus sakei: A Starter for Sausage Fermentation, a Protective Culture for Meat Products

Science.gov (United States)

Zagorec, Monique; Champomier-Vergès, Marie-Christine

2017-01-01

Among lactic acid bacteria of meat products, Lactobacillus sakei is certainly the most studied species due to its role in the fermentation of sausage and its prevalence during cold storage of raw meat products. Consequently, the physiology of this bacterium regarding functions involved in growth, survival, and metabolism during meat storage and processing are well known. This species exhibits a wide genomic diversity that can be observed when studying different strains and on which probably rely its multiple facets in meat products: starter, spoiler, or protective culture. The emerging exploration of the microbial ecology of meat products also revealed the multiplicity of bacterial interactions L. sakei has to face and their various consequences on microbial quality and safety at the end of storage. PMID:28878171

Starter Cultures: Uses in the Food Industry

DEFF Research Database (Denmark)

Hansen, Egon Bech

2014-01-01

Starter cultures are preparations of microorganisms serving as inoculants for the production of fermented foods. The production of cheese, yogurt, fermented milk, wine, sauerkraut, hams, and sausages occurs through the use of starter cultures that are consistent, predictable, and safe. The cultures...... provide the food products with a multitude of properties. Acidification of the food matrix is a primary property in a large number of food fermentations. Acidification activity often will be used to define packaging size and the unit of activity, whereas other characteristics differentiate a culture from...

Continuous ethanol production from sugar beet molasses using an osmotolerant mutant strain of zymomonas mobilis

Energy Technology Data Exchange (ETDEWEB)

Park, S.C.; Baratti, J.C. (Univ. de Provence, Marseille (France). Centre National de la Recherche Scientifique)

1992-01-25

In conventional alcohol fermentation processes using yeast species, the substrate cost represents a major fraction of the total production cost. Therefore, it may be very attractive to use the bacterium Zymomonas mobilis, since it has shown higher ethanol yields than yeasts when grown on a glucose-based medium. A report is made on the use of mutant strain of Zymomonas mobilis for ethanol production from hydrolyzed sugar beet molasses in a two-stage continuous culture which showed high ethanol yield and an ethanol concentration sufficiently high for economical recovery. A single stage continuous culture was first operated in an attempt to reduce the formation of sorbitol. Further on, a second fermentor was added with additional substrate feeding to increase the effluent ethanol concentration. An ethanol concentration of 59.9g/l was obtained at 97% sugar conversion and at high ethanol yield. The volumetric ethanol productivity was superior to that of batch fermentation but inferior to that of a single-stage continuous system with the same medium. However, the ethanol concentration was increased to a level acceptable for economical recovery. 18 refs., 3 figs., 5 tabs.

Fermentation of solid wastes in Switzerland; Feststoff-Vergaerung in der Schweiz. Schlussbericht 2007

Energy Technology Data Exchange (ETDEWEB)

Liesch, B.; Mueller, C.

2007-06-15

This final report for the Swiss Federal Office of Energy (SFOE) presents the results of a study on dry fermentation technologies. Information on the state-of-the-art of current dry fermentation systems is presented and the potential of implementing dry fermentation in Swiss agriculture is discussed. The study reveals that the current dry fermentation technologies provided by various enterprises are partly not suitable (complex, continuous operating digestion reactors, developed for handling municipal solid waste). Batch digestion reactors, however, are said by the authors to be mature for application in the Swiss agricultural area. Wet fermentation technologies are also quoted as being able to utilise organic substrates with high dry-matter content and are thus said to be economically more competitive than dry fermentation systems. Dry fermentation is quoted as being a technology with a high development potential. Details are presented on several continuous and non-continuous processes used. Also, the potential for the fermentation of solid wastes in Switzerland is reviewed. Experience made in Germany is also examined.

Health benefits of fermented foods: microbiota and beyond.

Science.gov (United States)

Marco, Maria L; Heeney, Dustin; Binda, Sylvie; Cifelli, Christopher J; Cotter, Paul D; Foligné, Benoit; Gänzle, Michael; Kort, Remco; Pasin, Gonca; Pihlanto, Anne; Smid, Eddy J; Hutkins, Robert

2017-04-01

Fermented foods and beverages were among the first processed food products consumed by humans. The production of foods such as yogurt and cultured milk, wine and beer, sauerkraut and kimchi, and fermented sausage were initially valued because of their improved shelf life, safety, and organoleptic properties. It is increasingly understood that fermented foods can also have enhanced nutritional and functional properties due to transformation of substrates and formation of bioactive or bioavailable end-products. Many fermented foods also contain living microorganisms of which some are genetically similar to strains used as probiotics. Although only a limited number of clinical studies on fermented foods have been performed, there is evidence that these foods provide health benefits well-beyond the starting food materials. Copyright © 2016 Elsevier Ltd. All rights reserved.

The influence of Lactobacillus paracasei LPC-37 on selected properties of fermented sausages

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Marcel Mati

2015-05-01

Full Text Available Fermented sausages rank among non-heat-treated meat products. Their nutritional properties are similar to the raw material, simultaneously their microbial safety and stability is ensured using additives and specific microbial cultures. The use of probiotic cultures can positively affect the processing of fermented sausages, resulting in the new technological properties and beneficial effect on human health. However, commercial application of probiotic microorganisms in fermented sausages is not common yet. Lactobacillus paracasei LPC-37 is a gram-positive, non-spore forming, homofermentative rod, which according to studies may modulate immune responses in human organism and survives the passage through the gastrointestinal tract. The main object of this work was to evaluate technological properties of L. paracasei LPC-37, which have not been fully examined. Two groups of fermented sausages were analysed in this work. The first group of fermented sausages was prepared using lyophilized starter culture (Lyocarni RHM-33. The second group of fermented sausages was prepared by the combination of lyophilized starter culture and potential probiotic culture Lactobacillus paracasei LPC-37. The processing and ripening of sausages were carried out in meat processing plant to simulate real conditions of production. The changes of the products (water activity, pH, concentration of organic acids and microbial growth were evaluated during ripening (3 weeks, while sensory analysis was carried out in the final stage of the process and during storage (3 weeks. It was found that the environment of raw-fermented sausages is suitable for the growth and survival of Lactobacillus paracasei LPC-37 and the microbiological quality of the final product was very good (absence of Salmonella and Listeria monocytogenes. The counts of lactobacilli reached 107 CFU/g of the product, which meet the requirements for functional foods. The results of the sensory evaluation showed

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.

Science.gov (United States)

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.

Effects of 2-hydroxy-4-(methylthio) butanoic acid (HMB) on microbial growth in continuous culture.

Science.gov (United States)

Noftsger, S M; St-Pierre, N R; Karnati, S K R; Firkins, J L

2003-08-01

2-Hydroxy-4-(methylthio) butanoic acid (HMB) positively affects milk composition and yield, potentially through ruminal actions. Four continuous culture fermenters were used to determine the optimal concentration of HMB for digestibility of organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF), and hemicellulose and synthesis of microbial N. A highly degradable mix of hay and grain was used as a basal diet to simulate a typical lactation diet. Three concentrations of HMB (0, 0.055, and 0.110%) and one concentration of dl-Met (0.097%) were infused into the fermenters according to a 4 x 4 Latin square design. Digesta samples were collected during the last 3 d of each of the four 10-d experimental periods. Digestibility of OM, hemicellulose, and NDF was largely insensitive to treatment. Digestibility of ADF showed a quadratic effect to supplementation of HMB, with 0.055% having lower digestibility than 0 or 0.110%. Total production of VFA was not influenced by HMB supplementation, but differences in concentration and production of individual VFA were seen. Isobutyrate increased linearly with increasing HMB supplementation. Propionate concentration decreased linearly with increased HMB supplementation, but propionate production showed a quadratic trend (P = 0.13). A higher concentration of acetate was detected for dl-Met compared with the highest HMB concentration. There were trends (P HMB. Microbial efficiency was not different among treatments. The proportion of bacterial N produced from NH3-N decreased linearly with increasing HMB, and bacteria receiving dl-Met synthesized more N from NH3-N than those receiving HMB. These data suggest that supplementation of HMB may have a sparing effect on branched chain volatile fatty acids because the fatty acids are not needed to provide carbon for synthesis of valine, isoleucine and leucine with ammonia. Comparisons of bacterial community structure in the fermenter effluent samples using PCR amplicons

Kinetic analysis of strains of lactic acid bacteria and acetic acid bacteria in cocoa pulp simulation media toward development of a starter culture for cocoa bean fermentation.

Science.gov (United States)

Lefeber, Timothy; Janssens, Maarten; Camu, Nicholas; De Vuyst, Luc

2010-12-01

The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes.

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

Science.gov (United States)

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

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

Science.gov (United States)

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.

Immunomodulation properties of multi-species fermented milks.

Science.gov (United States)

Foligné, Benoît; Parayre, Sandrine; Cheddani, Redouane; Famelart, Marie-Hélène; Madec, Marie-Noëlle; Plé, Coline; Breton, Jérôme; Dewulf, Joëlle; Jan, Gwénaël; Deutsch, Stéphanie-Marie

2016-02-01

Dairy propionibacteria (PAB) are used as a ripening starter in combination with Lactic acid bacteria (LAB) for dairy products such as Swiss-type cheese. LAB and PAB have also been studied for their probiotic properties but little is still known about their individual and/or synergistic beneficial effects within dairy matrices. In the context of a rising incidence of Inflammatory Bowel Diseases, it has become crucial to evaluate the immunomodulatory potential of bacteria ingested in large numbers via dairy products. We therefore selected different strains and combinations of technological LAB and PAB. We determined their immunomodulatory potential by IL-10 and IL-12 induction, in human peripheral blood mononuclear cells, on either single or mixed cultures, grown on laboratory medium or directly in milk. Milk was fermented with selected anti-inflammatory strains of LAB or PAB/LAB mixed cultures and the resulting bacterial fractions were also evaluated for these properties, together with starter viability and optimum technological aspects. The most promising fermented milks were evaluated in the context of TNBS- or DSS-induced colitis in mice. The improvement in inflammatory parameters evidenced an alleviation of colitis symptoms as a result of fermented milk consumption. This effect was clearly strain-dependent and modulated by growth within a fermented dairy product. These findings offer new tools and perspectives for the development of immunomodulatory fermented dairy products for targeted populations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Generation of flavour compounds in fermented sausages-the influence of curing ingredients, Staphylococcus starter culture and ripening time

DEFF Research Database (Denmark)

Olesen, Pelle Thonning; Meyer, Anne Boye Strunge; Stahnke, Louise Heller

2004-01-01

The volatile profiles of fermented sausages made with either Staphylococcus xylosus or Staphylococcus carnosus starter cultures were studied with regard to the influence of salt concentration, ripening time and three different combinations of curing ingredients-nitrate, nitrite or nitrite...... throughout maturation. Curing salts had a pronounced effect on the level of volatile compounds. In particular, curing with nitrate instead of nitrite resulted in a striking difference. Generally, nitrate increased the level of volatile compounds compared to nitrite, whereas ascorbate had only a small...... observed depending on whether S. xylosus or S. carnosus were used as starter culture. In particular the effects of nitrate was much more predominant in the sausages made with S. carnosus than S. xylosus....

Discovery and History of Amino Acid Fermentation.

Science.gov (United States)

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.

Enzymatic hydrolysis and fermentation of agricultural residues to ethanol

Energy Technology Data Exchange (ETDEWEB)

Mes-Hartree, M.; Hogan, C.M.; Saddler, J.N.

1984-01-01

A combined enzymatic hydrolysis and fermentation process was used to convert steam-treated wheat and barley straw to ethanol. Maximum conversion efficiencies were obtained when the substrates were steamed for 90 s. These substrates could yield over 0.4 g ethanol/g cellulose following a combined enzymatic hydrolysis and fermentation process procedure using culture filtrates derived from Trichoderma harzianum E58. When culture filtrates from Trichoderma reesei C30 and T. reesei QM9414 were used, the ethanol yields obtained were 0.32 and 0.12 g ethanol/g cellulose utilized, respectively. The lower ethanol yields obtained with these strains were attributed to the lower amounts of ..beta..-glucosidase detected in the T. reesei culture filtrates.

A Small-Volume, Low-Cost, and Versatile Continuous Culture Device.

Directory of Open Access Journals (Sweden)

Dominick Matteau

Full Text Available Continuous culture devices can be used for various purposes such as establishing reproducible growth conditions or maintaining cell populations under a constant environment for long periods. However, commercially available instruments are expensive, were not designed to handle small volumes in the milliliter range, and can lack the flexibility required for the diverse experimental needs found in several laboratories.We developed a versatile continuous culture system and provide detailed instructions as well as a graphical user interface software for potential users to assemble and operate their own instrument. Three culture chambers can be controlled simultaneously with the proposed configuration, and all components are readily available from various sources. We demonstrate that our continuous culture device can be used under different modes, and can easily be programmed to behave either as a turbidostat or chemostat. Addition of fresh medium to the culture vessel can be controlled by a real-time feedback loop or simply calibrated to deliver a defined volume. Furthermore, the selected light-emitting diode and photodetector enable the use of phenol red as a pH indicator, which can be used to indirectly monitor the bulk metabolic activity of a cell population rather than the turbidity.This affordable and customizable system will constitute a useful tool in many areas of biology such as microbial ecology as well as systems and synthetic biology.

Quality of fermented whey beverage with milk

Directory of Open Access Journals (Sweden)

Rakin Marica B.

2016-01-01

Full Text Available One of the most economical ways of whey processing is the production of beverages, that represents a single process that exploits all the potential of whey as a raw material. Functional and sensory characteristics of whey based beverages are a criterion that is crucial to the marketing of products and win over consumers. The aim of this study was to determine nutritional and functional characteristics of fermented whey beverage with milk and commercial ABY-6 culture. The results showed that the applied starter culture can be used for the production of fermented whey based beverage with satisfactory nutritional properties. Addition of milk was important not only in the nutritional quality of the resulting product, but also improved the taste, the homogeneity and stability. Analysis of the chemical composition of fermented whey based beverage and nutritional information about it indicates that the product is a good source of protein and calcium. Fermented beverage contained 8.07 log (CFU/mL, showed antioxidant activity of at least 38.1% and the titratable acidity of 28.2°SH corresponding to the acidity of the product in this category. [Projekat Ministarstva nauke Republike Srbije, br. TR 31017 i br. 451-03-00605/2012-16/85

Exploitation of sweet sorghum biomass for biofuel production using mixed acidogenic and methanogenic cultures and pure cultures of ruminococcus albus

International Nuclear Information System (INIS)

Ntaikou, I.; Antonopoulou, G.; Marazioti, C.; Lyberatos, G.

2008-01-01

Full text: The present study focuses on the exploitation of sweet sorghum biomass for gas biofuel production in continuous and batch systems. Sweet sorghum is an annual C 4 plant of tropical origin, well-adapted to sub-tropical and temperate regions and highly productive in biomass. It is rich in readily fermentable sugars and thus it can be considered as an excellent raw material for biohydrogen production from many different fermentative microorganisms. Extraction of free sugars from the sorghum stalks was achieved using water at 30 degrees centigrade. After the extraction process a liquid fraction (sorghum extract), rich in sucrose, and a solid fraction (sorghum cellulosic-hemicellulosic residues or sorghum bagasse), containing the cellulose and hemicelluloses, were obtained. A two-step continuous process was developed for the biological hydrogen production and the subsequent production of biogas from sweet sorghum extract. In the first reactor sugars were fermented to hydrogen, volatile fatty acids and alcohols b mixed acidogenic culture derived from the indigenous microfauna of sweet sorghum. The hydrogen producing reactor was operated at five different hydraulic retention times (HRT), i.e 24h, 12h, 8h, 6h and 4h. The HRT of 12h proved to be the most effective leading to the production 10.4 L H 2 /kg sweet sorghum biomass. Subsequently, the effluent was fed to the methanogenic reactor, where all the residual organic compounds were digested by an acclimated methanogenic culture derived from activated sludge. The operation of the methanogenic reactor was studied at three different HRTs, i.e 20d, 15d and 10d with the latter being the most prosing leading to the production 35.2 L CH 4 /kg sweet sorghum biomass. Both continuous and batch cultures were used for the investigation of hydrogen production from sweet sorghum biomass using Ruminococcus albus. R. albus is an important, fibrolytic bacterium of the rumen that can hydrolyse both cellulose and hemicellulose

Unique Microbial Diversity and Metabolic Pathway Features of Fermented Vegetables From Hainan, China

OpenAIRE

Qiannan Peng; Shuaiming Jiang; Jieling Chen; Chenchen Ma; Dongxue Huo; Yuyu Shao; Jiachao Zhang; Jiachao Zhang

2018-01-01

Fermented vegetables are typically traditional foods made of fresh vegetables and their juices, which are fermented by beneficial microorganisms. Herein, we applied high-throughput sequencing and culture-dependent technology to describe the diversities of microbiota and identify core microbiota in fermented vegetables from different areas of Hainan Province, and abundant metabolic pathways in the fermented vegetables were simultaneously predicted. At the genus level, Lactobacillus bacteria we...

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

Science.gov (United States)

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.

Dynamics of microbial community during the extremely long-term fermentation process of a traditional soy sauce.

Science.gov (United States)

Yang, Yang; Deng, Yue; Jin, Yulan; Liu, Yanxi; Xia, Baixue; Sun, Qun

2017-08-01

Soy sauce produced by long-term natural fermentation is a traditional specialty in Asia, with a reputation for superior quality and rich flavour. In this study, both culture-dependent and culture-independent approaches were used to investigate the microbial diversity and community dynamics during an extremely long-term (up to 4 years) natural fermentation of Xianshi Soy Sauce, a national intangible cultural heritage. Genera of Bacillus, Aspergillus and Cladosporium were detected by both methods above. The relative abundance of the genera Bacillus and Weissella was significantly higher in the late stage than in the early one, while the genera Klebsiella and Shimwellia were opposite (P fermentation time, while there was a fair homogeneousness among samples of the same year, especially during the late fermentation stage. The clustering analysis tended to separate the fermented mashes of the 4th year from the earlier stages, suggesting the necessity of the long fermentation period for developing distinctive microbiota and characteristic quality-related compounds. This is the first report to explore the temporal changes in microbial dynamics over a period of 4 years in traditional fermentation of soy sauce, and this work illustrated the importance of isolation of appropriate strains to be used as starter cultures in brewing processes. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Utilization of date carbohydrate as substrate in microbial fermentation

Energy Technology Data Exchange (ETDEWEB)

Kamel, B.S.

1979-06-01

In a study of 3 yeasts, ogi yeast showed the highest conversion rate and cell production in both shake flasks and fermenters using a juice with 4% soluble solids extracted from dates with an average of 65% sugar. Corn steep liquor increased the growth rate, 4% having the greatest effect. The highest cell production of the ogi yeast was at 37 degrees (4.92 g/L) and 50% of the sugar was converted. An associative fermentation using a mixed culture of Candida utilis and Saccharomyces cerevisiae gave better results than fermentations using each organism alone. The fermentation using S.rouxxi NRRL Y-2547 was also studied.

Removing Bacillus subtilis from fermentation broth using alumina nanoparticles.

Science.gov (United States)

Mu, Dashuai; Mu, Xin; Xu, Zhenxing; Du, Zongjun; Chen, Guanjun

2015-12-01

In this study, an efficient separation technology using Al2O3 nanoparticles (NPs) was developed for removing Bacillus subtilis from fermentation broth. The dosage of alumina nanoparticles used for separating B. subtilis increased during the culture process and remained stable in the stationary phase of the culture process. The pH of the culture-broth was also investigated for its effects on flocculation efficiency, and showed an acidic pH could enhance the flocculation efficiency. The attachment mechanisms of Al2O3 NPs to the B. subtilis surface were investigated, and the zeta potential analysis showed that Al2O3 NPs could attach to B. subtilis via electrostatic attachment. Finally, the metabolite content and the antibacterial effect of the fermentation supernatants were detected and did not significantly differ between alumina nanoparticle separation and centrifugation separation. Together, these results indicate a great potential for a highly efficient and economical method for removing B. subtilis from fermentation broth using alumina nanoparticles. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of Novel Starter Culture on Reduction of Biogenic Amines, Quality Improvement, and Sensory Properties of Doenjang, a Traditional Korean Soybean Fermented Sauce Variety.

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Shukla, Shruti; Lee, Jong Suk; Park, Hae-Kyong; Yoo, Jung-Ah; Hong, Sung-Yong; Kim, Jong-Kyu; Kim, Myunghee

2015-08-01

To select appropriate microorganisms as starter cultures for the reliable and reproducible fermentation of soybean fermented products of Korean Doenjang, various ratios of fungi (Aspergillus oryzae J, Mucor racemosus 15, M. racemosus 42) combined with Bacillus subtilis TKSP 24 were selected as either single, double, or multiple Meju strains for commercial mass production of Doenjang, followed by analysis of sensory characteristics. In the sensory evaluation, Doenjang BAM15-1 and BAM42-1, which were fermented with multiple strains (1:1:1), showed the highest sensory scores as compared to control. Based on sensory characteristics, 6 Doenjang samples were subjected to quantitative determination of amino acids, free sugars, and organic acids (volatile and nonvolatile) contents, followed by determination of biogenic amines. Total sweet taste amino acid contents were highest in BAM15-1 and BAM42-1 samples (333.7 and 295.8 mg/100 g, respectively) and similar that of control (391.1 mg/100 g). Samples BAM15-1 and BAM42-1 showed the relatively high volatile and nonvolatile organic acid contents (154.24, 192.26, and 71.31, 82.42 mg/100 g, respectively). In addition, BAM15-1 and BAM42-1 showed negligible biogenic amine formation, ranging from 0.00 to 1.02 and 0.00 to 3.92 mg/100 g, respectively. These findings indicate that determination of food components along with sensory and quality attributes using multiple microbial Meju strains as a starter culture may provide substantial results on improved quality fermented Doenjang products. © 2015 Institute of Food Technologists®

Kinetic Analysis of Strains of Lactic Acid Bacteria and Acetic Acid Bacteria in Cocoa Pulp Simulation Media toward Development of a Starter Culture for Cocoa Bean Fermentation ▿

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Lefeber, Timothy; Janssens, Maarten; Camu, Nicholas; De Vuyst, Luc

2010-01-01

The composition of cocoa pulp simulation media (PSM) was optimized with species-specific strains of lactic acid bacteria (PSM-LAB) and acetic acid bacteria (PSM-AAB). Also, laboratory fermentations were carried out in PSM to investigate growth and metabolite production of strains of Lactobacillus plantarum and Lactobacillus fermentum and of Acetobacter pasteurianus isolated from Ghanaian cocoa bean heap fermentations, in view of the development of a defined starter culture. In a first step, a selection of strains was made out of a pool of strains of these LAB and AAB species, obtained from previous studies, based on their fermentation kinetics in PSM. Also, various concentrations of citric acid in the presence of glucose and/or fructose (PSM-LAB) and of lactic acid in the presence of ethanol (PSM-AAB) were tested. These data could explain the competitiveness of particular cocoa-specific strains, namely, L. plantarum 80 (homolactic and acid tolerant), L. fermentum 222 (heterolactic, citric acid fermenting, mannitol producing, and less acid tolerant), and A. pasteurianus 386B (ethanol and lactic acid oxidizing, acetic acid overoxidizing, acid tolerant, and moderately heat tolerant), during the natural cocoa bean fermentation process. For instance, it turned out that the capacity to use citric acid, which was exhibited by L. fermentum 222, is of the utmost importance. Also, the formation of mannitol was dependent not only on the LAB strain but also on environmental conditions. A mixture of L. plantarum 80, L. fermentum 222, and A. pasteurianus 386B can now be considered a mixed-strain starter culture for better controlled and more reliable cocoa bean fermentation processes. PMID:20889778

Screening and optimization of some inorganic salts for the production of ergot alkaloids from Penicillium species using surface culture fermentation process.

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Shahid, Memuna Ghafoor; Nadeem, Muhammad; Baig, Shahjehan; Cheema, Tanzeem Akbar; Atta, Saira; Ghafoor, Gul Zareen

2016-03-01

The present study deals with the production of ergot alkaloids from Penicillium commune and Penicillium citrinum, using surface culture fermentation process. Impact of various inorganic salts was tested on the production of ergot alkaloids during the optimization studies of fermentation medium such as impact of various concentration levels of succinic acid, ammonium chloride, MgSO4, FeSO4, ZnSO4, pH and the effect of various incubation time periods was also determined on the production of ergot alkaloids from Penicillium commune and Penicillium citrinum. Highest yield of ergot alkaloids was obtained when Penicillium commune and Penicillium citrinum that were grown on optimum levels of ingredients such as 2 g succinic acid, 1.5 and 2 g NH4Cl, 1.5 g MgSO4, 1 g FeSO4, 1 and 1.5 g ZnSO4 after 21 days of incubation time period using pH 5 at 25(°)C incubation temperature in the fermentation medium. Ergot alkaloids were determined using Spectrophotometry and Thin Layer Chromatography (TLC) techniques.

Use of disposable reactors to generate inoculum cultures for E. coli production fermentations.

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Mahajan, Ekta; Matthews, Timothy; Hamilton, Ryan; Laird, Michael W

2010-01-01

Disposable technology is being used more each year in the biotechnology industry. Disposable bioreactors allow one to avoid expenses associated with cleaning, assembly and operations, as well as equipment validation. The WAVE bioreactor is well established for Chinese Hamster Ovary (CHO) production, however, it has not yet been thoroughly tested for E. coli production because of the high oxygen demand and temperature maintenance requirements of that platform. The objective of this study is to establish a robust process to generate inoculum for E. coli production fermentations in a WAVE bioreactor. We opted not to evaluate the WAVE system for production cultures because of the high cell densities required in our current E. coli production processes. Instead, the WAVE bioreactor 20/50 system was evaluated at laboratory scale (10-L) to generate inoculum with target optical densities (OD(550)) of 15 within 7-9 h (pre-established target for stainless steel fermentors). The maximum settings for rock rate (40 rpm) and angle (10.5) were used to maximize mass transfer. The gas feed was also supplemented with additional oxygen to meet the high respiratory demand of the culture. The results showed that the growth profiles for the inoculum cultures were similar to those obtained from conventional stainless steel fermentors. These inoculum cultures were subsequently inoculated into 10-L working volume stainless steel fermentors to evaluate the inocula performance of two different production systems during recombinant protein production. The results of these production cultures using WAVE inocula showed that the growth and recombinant protein production was comparable to the control data set. Furthermore, an economic analysis showed that the WAVE system would require less capital investment for installation and operating expenses would be less than traditional stainless steel systems. (c) 2010 American Institute of Chemical Engineers

A Novel Millet-Based Probiotic Fermented Food for the Developing World

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Elisa Di Stefano

2017-05-01

Full Text Available Probiotic yogurt, comprised of a Fiti sachet containing Lactobacillus rhamnosus GR-1 and Streptococcus thermophilus C106, has been used in the developing world, notably Africa, to alleviate malnutrition and disease. In sub-Saharan African countries, fermentation of cereals such as millet, is culturally significant. The aim of this study was to investigate the fermentation capability of millet when one gram of the Fiti sachet consortium was added. An increase of 1.8 and 1.4 log CFU/mL was observed for S. thermophilus C106 and L. rhamnosus GR-1 when grown in 8% millet in water. Single cultures of L. rhamnosus GR-1 showed the highest μmax when grown in the presence of dextrose, galactose and fructose. Single cultures of S. thermophilus C106 showed the highest μmax when grown in the presence of sucrose and lactose. All tested recipes reached viable counts of the probiotic bacteria, with counts greater than 106 colony-forming units (CFU/mL. Notably, a number of organic acids were quantified, in particular phytic acid, which was shown to decrease when fermentation time increased, thereby improving the bioavailability of specific micronutrients. Millet fermented in milk proved to be the most favorable, according to a sensory evaluation. In conclusion, this study has shown that sachets being provided to African communities to produce fermented milk, can also be used to produce fermented millet. This provides an option for when milk supplies are short, or if communities wish to utilize the nutrient-rich qualities of locally-grown millet.

Effect of fermented Banana peel on Broiler Carcass

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Koni TNI

2013-06-01

Full Text Available This experiment was conducted to examine effect of inclusion of fermented banana peel by Rhyzopus oligosporus in diets on slaughter weight, carcass weight and carcass percentage, weight and percentage abdominal fat of broiler. The experiment was done based on Completely Randomized Design with four treatments and four replications and each replication consisted of six chickens. The treatment were R0 = without banana peel fermented, R1 = 5% banana peel fermented, R2 = 10% banana peel fermented, R3 = 15% banana peel fermented. Data of the experiment were analyzed, using ANOVA and then continued with Duncan's Multiple Range Test. Result showed that level of fermented banana peel affected slaughter weight and carcass weight. However carcass persentage, weight and percentage of abdominal fat was not affected by treatment. Banana peel fermented by Rhizopus oligosporus could can be used maximally 10% in broiler ration.

Kinetics of alcoholic fermentation during the culturing of bakers' yeast

Energy Technology Data Exchange (ETDEWEB)

Franz, B

1961-01-01

A synthesis was made of the effects of various factors on the rate of fermentation by Saccharomyces cerevisiae. The rate obeyed the Michaelis-Menten equation, was independent of the concentration of yeast, was maximal at 20/sup 0/ (0.61 ml ethanol/g dry yeast/h), was not significantly affected between pH 6.5 and 3.0 but declined at 3.0, was inhibited by ethanol at a rate proportional to the concentration squared (at ethanol = 12 volume %, the fermentation rate was practically zero), and was enhanced by the addition of phosphorus when a P-poor yeast was employed.

The effect of microbial starter composition on cassava chips fermentation for the production of fermented cassava flour

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Kresnowati, M. T. A. P.; Listianingrum, Zaenudin, Ahmad; Trihatmoko, Kharisrama

2015-12-01

The processing of cassava into fermented cassava flour (fercaf) or the widely known as modified cassava flour (mocaf) presents an alternative solution to improve the competitiveness of local foods and to support national food security. However, the mass production of fercaf is being limited by several problems, among which is the availability of starter cultures. This paper presents the mapping of the effect of microbial starter compositions on the nutritional content of fercaf in order to obtain the suitable nutritional composition. Based on their enzymatic activities, the combination of Lactobacillus plantarum, Bacillus subtilis, and Aspergillus oryzae were tested during the study. In addition, commercial starter was also tested. During the fermentation, the dynamics in microbial population were measured as well as changes in cyanogenic glucoside content. The microbial starter composition was observed to affect the dynamics in microbial populationcynaogenic glucoside content of the produced fercaf. In general, steady state microbial population was reached within 12 hours of fermentation. Cyanogenic glucoside was observed to decrease along the fermentation.

Daqu : a traditional fermentation starter in China: microbial ecology and functionality

NARCIS (Netherlands)

Zheng, X.

2015-01-01

Abstract

Fermented products have high nutritional value and constitute an important part of the Chinese dietary profile; they are also gaining popularity throughout the world. Daqu is a traditional natural fermentation starter culture that has a significant impact on the

Cultural continuity, traditional Indigenous language, and diabetes in Alberta First Nations: a mixed methods study.

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Oster, Richard T; Grier, Angela; Lightning, Rick; Mayan, Maria J; Toth, Ellen L

2014-10-19

We used an exploratory sequential mixed methods approach to study the association between cultural continuity, self-determination, and diabetes prevalence in First Nations in Alberta, Canada. We conducted a qualitative description where we interviewed 10 Cree and Blackfoot leaders (members of Chief and Council) from across the province to understand cultural continuity, self-determination, and their relationship to health and diabetes, in the Alberta First Nations context. Based on the qualitative findings, we then conducted a cross-sectional analysis using provincial administrative data and publically available data for 31 First Nations communities to quantitatively examine any relationship between cultural continuity and diabetes prevalence. Cultural continuity, or "being who we are", is foundational to health in successful First Nations. Self-determination, or "being a self-sufficient Nation", stems from cultural continuity and is seriously compromised in today's Alberta Cree and Blackfoot Nations. Unfortunately, First Nations are in a continuous struggle with government policy. The intergenerational effects of colonization continue to impact the culture, which undermines the sense of self-determination, and contributes to diabetes and ill health. Crude diabetes prevalence varied dramatically among First Nations with values as low as 1.2% and as high as 18.3%. Those First Nations that appeared to have more cultural continuity (measured by traditional Indigenous language knowledge) had significantly lower diabetes prevalence after adjustment for socio-economic factors (p =0.007). First Nations that have been better able to preserve their culture may be relatively protected from diabetes.

The influence of inoculum composition on selected bioactive and nutritional parameters of grass pea tempeh obtained by mixed-culture fermentation with Rhizopus oligosporus and Aspergillus oryzae strains.

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Starzynska-Janiszewska, A; Stodolak, B; Dulinski, R; Mickowska, B

2012-04-01

Tempeh is a popular Indonesian product obtained from legume seeds by solid-state fermentation with Rhizopus sp. The aim of this research was to study the effect of simultaneous mixed-culture fermentation of grass pea seeds on selected parameters of products as compared to traditional tempeh. The inoculum contained different ratios of Rhizopus oligosporus and Aspergillus oryzae spores. The simultaneous fermentation of grass pea seeds with inoculum consisting of 1.2 × 10(6) R. oligosporus and 0.6 × 10(6) A. oryzae spores (per 60 g of seeds) resulted in a product of improved quality, as compared with traditionally made tempeh (obtained after inoculation with 1.2 × 10(6) R. oligosporus spores), at the same fermentation time. This product had radical scavenging ability 70% higher than the one obtained with pure R. oligosporus culture and contained 2.23 g/kg dm of soluble phenols. The thiamin and riboflavin levels were above three (340 µg/g dm) and two (50.50 µg/g dm) folds higher than in traditionally made tempeh, respectively. The product had 65% in vitro bioavailability of proteins and 33% in vitro bioavailability of sugars. It also contained 40% less 3-N-oxalyl-L-2, 3-diaminopropionic acid (0.074 g/kg dm), as compared to traditional tempeh.

Fermentation and antimicrobial characteristics of Lactobacillus plantarum and Candida tropicalis from Nigerian fermented maize (akamu

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Patience Chisa Obinna-Echem

2014-10-01

Full Text Available This study investigated the ability of Lactobacillus plantarum strains (NGL5 and NGL7 and Candida tropicalis (NGY1 previously identified from akamu-a Nigerian fermented maize food with probiotic L. plantarum LpTx and Saccharomyces boulardii SB20 to ferment ground maize slurries based on pH, acidity, microbial biomass, levels of sugars and organic acids, and their antimicrobial activity against Salmonella enterica serovar Enteritidis NCTC 5188, Escherichia coli NCTC 11560, Bacillus cereus NCIMB 11925, Staphylococcus aureus NCTC 3750 and Listeria monocytogenes NCTC 7973 using an agar spot assay. L. plantarum strains either as single or mixed starter cultures with the yeasts had growth rates ≥0.15 h-1,with pH significantly (p≤0.05 decreased to ≤3.93 after 12 h and then to ≤3.52 after 72 h and lactic acid >84 mmol L-1. The yeasts had growth rates ≥0.18 h-1 but pH was ≥4.57 with lactic acid levels ≤20.23 mmol L-1 after 72 h in the single culture fermentation. There was no inhibition in modified MRS agar: 0.2% glucose and 0.2% glucose without Tween 80. Inhibition halos in MRS agar varied from 10.6 to 23.9 mm. S. bourladii was more inhibitory towards L. monocytogenes (8.6 mm and B. cereus (5.4 mm than was C. tropicalis (1.1 and 3.3 mm for L. monocytogenes NCTC 7973 and B. cereus NCIMB 11925 respectively (0.9 mm in malt extract agar. This study showed that C. tropicalis was less inhibitory to the pathogens while antimicrobial activities of the L. plantarum strains were mainly due to acidity and the L. plantarum strains either as single or mixed cultures with the yeasts demonstrated strong fermentation ability, with significant decrease in pH which is vital in the choice of starter for product safety.

Combined moist airtight storage and feed fermentation of barley by the yeast Wickerhamomyces anomalus and a lactic acid bacteria consortium

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Jenny eBorling Welin

2015-04-01

Full Text Available This study combined moist airtight storage of moist grain with pig feed fermentation. Starter cultures with the potential to facilitate both technologies were added to airtight stored moist crimped cereal grain, and the impact on storage microflora and the quality of feed fermentations generated from the grain was investigated. Four treatments were compared: three based on moist barley, either un inoculated (M, inoculated with Wickerhamomyces anomalus (W, or inoculated with W. anomalus and LAB starter culture, containing Pediococcus acidilactici DSM 16243, Pediococcus pentosaceus DSM 12834 and Lactobacillus plantarum DSM 12837 (WLAB; and one treatment based on dried barley (D. After 6 weeks of storage, four feed fermentations FM, FW, FWLAB, and FD, were initiated from M, W, WLAB and D, respectively, by mixing the grain with water to a dry matter content of 30%. Each treatment was fermented in batch initially for 7 days and then kept in a continuous mode by adding new feed daily with 50% back-slop. During the 6 week storage period, the average water activity decreased in M, W and WLAB from 0.96 to 0.85, and cereal pH decreased from approximately 6.0 at harvest to 4.5. Feed fermentation conferred a further pH decrease to 3.8 – 4.1. In M, W and WLAB, moulds and Enterobacteriaceae were mostly below detection limit, whereas both organism groups were detected in D. In fermented feed, Enterobacteriaceae were below detection limit in almost all conditions. Moulds were detected in FD, for most of the fermentation time in FM and at some sampling points in FW and FWLAB. Starter organisms, especially W. anomalus and L. plantarum comprised a considerable proportion of the yeast and LAB populations, respectively, in both stored grain and fermented feed. However, autochthonous Pichia kudriavzevii and Kazachstania exigua partially dominated the yeast populations in stored grain and fermented feed, respectively.

Production of fungal antibiotics using polymeric solid supports in solid-state and liquid fermentation.

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Bigelis, Ramunas; He, Haiyin; Yang, Hui Y; Chang, Li-Ping; Greenstein, Michael

2006-10-01

The use of inert absorbent polymeric supports for cellular attachment in solid-state fungal fermentation influenced growth, morphology, and production of bioactive secondary metabolites. Two filamentous fungi exemplified the utility of this approach to facilitate the discovery of new antimicrobial compounds. Cylindrocarpon sp. LL-Cyan426 produced pyrrocidines A and B and Acremonium sp. LL-Cyan416 produced acremonidins A-E when grown on agar bearing moist polyester-cellulose paper and generated distinctly different metabolite profiles than the conventional shaken or stationary liquid fermentations. Differences were also apparent when tenfold concentrated methanol extracts from these fermentations were tested against antibiotic-susceptible and antibiotic-resistant Gram-positive bacteria, and zones of inhibition were compared. Shaken broth cultures of Acremonium sp. or Cylindrocarpon sp. showed complex HPLC patterns, lower levels of target compounds, and high levels of unwanted compounds and medium components, while agar/solid support cultures showed significantly increased yields of pyrrocidines A and B and acremonidins A-E, respectively. This method, mixed-phase fermentation (fermentation with an inert solid support bearing liquid medium), exploited the increase in surface area available for fungal growth on the supports and the tendency of some microorganisms to adhere to solid surfaces, possibly mimicking their natural growth habits. The production of dimeric anthraquinones by Penicillium sp. LL-WF159 was investigated in liquid fermentation using various inert polymeric immobilization supports composed of polypropylene, polypropylene cellulose, polyester-cellulose, or polyurethane. This culture produced rugulosin, skyrin, flavomannin, and a new bisanthracene, WF159-A, after fermentation in the presence and absence of polymeric supports for mycelial attachment. The physical nature of the different support systems influenced culture morphology and relative

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

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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.

Fermented Dairy Products in the Nutrition of Infants in the Russian Federation: Past and Present

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Tatiana E. Borovik

2016-01-01

Full Text Available Fermented dairy products have a high nutritional and biological value and functional properties beneficial to human health; they are very diverse and have a long history. Fermentation of milk is a complex technological, physical and biochemical process that occurs under the influence of two enzymes of lactic acid bacteria — -galactosidase and lactate dehydrogenase. Requirements for biological properties of starter microorganisms and fermentation technology are strictly regulated. Based on the starter cultures used, we can single out fermented dairy products of lactic acid and mixed (lactic acid and alcohol fermentation. There are adapted, partially adapted and non-adapted cultured milk products for children, some of which are enriched with pro- and prebiotics to enhance functional properties. The article provides information about one of the first Russian non-adapted fermented milk products for infants enriched with inulin, fruit and cereals.

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

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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.

In vitro continuous fermentation model (PolyFermS) of the swine proximal colon for simultaneous testing on the same gut microbiota.

Science.gov (United States)

Tanner, Sabine A; Zihler Berner, Annina; Rigozzi, Eugenia; Grattepanche, Franck; Chassard, Christophe; Lacroix, Christophe

2014-01-01

In vitro gut modeling provides a useful platform for a fast and reproducible assessment of treatment-related changes. Currently, pig intestinal fermentation models are mainly batch models with important inherent limitations. In this study we developed a novel in vitro continuous fermentation model, mimicking the porcine proximal colon, which we validated during 54 days of fermentation. This model, based on our recent PolyFermS design, allows comparing different treatment effects on the same microbiota. It is composed of a first-stage inoculum reactor seeded with immobilized fecal swine microbiota and used to constantly inoculate (10% v/v) five second-stage reactors, with all reactors fed with fresh nutritive chyme medium and set to mimic the swine proximal colon. Reactor effluents were analyzed for metabolite concentrations and bacterial composition by HPLC and quantitative PCR, and microbial diversity was assessed by 454 pyrosequencing. The novel PolyFermS featured stable microbial composition, diversity and metabolite production, consistent with bacterial activity reported for swine proximal colon in vivo. The constant inoculation provided by the inoculum reactor generated reproducible microbial ecosystems in all second-stage reactors, allowing the simultaneous investigation and direct comparison of different treatments on the same porcine gut microbiota. Our data demonstrate the unique features of this novel PolyFermS design for the swine proximal colon. The model provides a tool for efficient, reproducible and cost-effective screening of environmental factors, such as dietary additives, on pig colonic fermentation.

In vitro continuous fermentation model (PolyFermS of the swine proximal colon for simultaneous testing on the same gut microbiota.

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Sabine A Tanner

Full Text Available In vitro gut modeling provides a useful platform for a fast and reproducible assessment of treatment-related changes. Currently, pig intestinal fermentation models are mainly batch models with important inherent limitations. In this study we developed a novel in vitro continuous fermentation model, mimicking the porcine proximal colon, which we validated during 54 days of fermentation. This model, based on our recent PolyFermS design, allows comparing different treatment effects on the same microbiota. It is composed of a first-stage inoculum reactor seeded with immobilized fecal swine microbiota and used to constantly inoculate (10% v/v five second-stage reactors, with all reactors fed with fresh nutritive chyme medium and set to mimic the swine proximal colon. Reactor effluents were analyzed for metabolite concentrations and bacterial composition by HPLC and quantitative PCR, and microbial diversity was assessed by 454 pyrosequencing. The novel PolyFermS featured stable microbial composition, diversity and metabolite production, consistent with bacterial activity reported for swine proximal colon in vivo. The constant inoculation provided by the inoculum reactor generated reproducible microbial ecosystems in all second-stage reactors, allowing the simultaneous investigation and direct comparison of different treatments on the same porcine gut microbiota. Our data demonstrate the unique features of this novel PolyFermS design for the swine proximal colon. The model provides a tool for efficient, reproducible and cost-effective screening of environmental factors, such as dietary additives, on pig colonic fermentation.

Feeding of Aspergillus oryzae fermentation culture (AOFC to growing sheep: 2. Growth rate and feed efficiency

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D Lubis

2002-12-01

Full Text Available Utilization of yeast and or filamentous fungi as feed additive to ruminants has been of interest since the late 1980’s. Two fungi species have been commercially produced in the United States, (1 Yea-Sacc containing living cells of Saccharomyces cerevisiae and (2 Amaferm bearing Aspergillus oryzae fermentation extract. It has been demonstrated and proven that the cultures can enhance rumen development and function in young ruminants. This paper concerns the use of Aspergillus oryzae fermentation culture (AOFC as feed additive for young-growing male ‘Garut’ sheep. The A. oryzae was cultured in a media made of mineral-enriched ‘onggok’ flour, a material of tapioca processing waste. The AOFC was prepared gradually by incubating the fungus at room temperature (26 – 300C for 5 days, dried at 400C and ground. The AOFC was added to a commercial concentrate (GT-03 at 0, 5 and 10% (w/w levels, as treatment C0 (control, C1, and C2, respectively. Fifteen growing ‘Garut’ sheep were used and the concentrate feed treatments were randomly allotted based on a randomized block design. Drinking water was available at all time. The amount of feed offered (chopped King grass and concentrates and their refusals were weighed daily and live-weight of sheep was measured once a week in the morning. Daily feces was collected and weighed in the last 10 days of the 14-week experimental period. All feed and fecal samples were analyzed for dry matter, crude protein, total fiber (NDF, and ash. AOFC supplementation resulted in higher weight gains (P<0.05, which were 94.81; 122.08; and 140.52 g/d for C0, C1, and C2 treatments, respectively. Dry and organic matter, as well as protein intake was also significantly increased by inclusion of AOFC into concentrate diet (P<0.05. The increment in nutrient intake was from increased consumption of concentrates, and not from King grass, however, there was no effect of AOFC supplementation on feed efficiency.

Use of biomass energy. Saccharification of raw starch and ethanol fermentation

Energy Technology Data Exchange (ETDEWEB)

Ueda, S

1982-01-01

Raw starch was saccharified under acidic condition of pH 3.5 using black-koji amylase, and the resultant saccharidies were fermented to give ethanol in succession. White polished rice flour was fermented at 30 degrees C during the period of 7 to 10 days to give ethanol. Semi-continuous ethanol fermentation was carried out using corn starch and cassava starch. Batch ethanol fermentation was also carried out using cassava or sweet potato. Sweet potato was fermented using Rhizopus gluco-amylase. 11 references.

Microbiological Research on the Traditional Alcoholic Fermented Milk“Airag”in Mongolia

OpenAIRE

宮本, 拓

2015-01-01

　Airag, a traditional fermented milk well loved by Mongolians, has been drunk habitually sinceancient times as a unique drink. It is produced from cow, mare and camel milk by a traditional method using indigenous starter cultures containing lactic acid bacteria, yeasts and other fermentative microorganisms. Spontaneously fermented milk products have for centuries been consumed for their therapeutic value in promoting health and well-being, especially among the pastoral communities in Mongolia...

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

Science.gov (United States)

Hildebrand, Bastian; Boguhn, Jeannette; Rodehutscord, Markus

2011-10-01

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

Spontaneous Food Fermentations and Potential Risks for Human Health

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Vittorio Capozzi

2017-09-01

Full Text Available Fermented foods and beverages are a heterogeneous class of products with a relevant worldwide significance for human economy, nutrition and health for millennia. A huge diversity of microorganisms is associated with the enormous variety in terms of raw materials, fermentative behavior and obtained products. In this wide microbiodiversity it is possible that the presence of microbial pathogens and toxic by-products of microbial origin, including mycotoxins, ethyl carbamate and biogenic amines, are aspects liable to reduce the safety of the consumed product. Together with other approaches (e.g., use of preservatives, respect of specific physico-chemical parameters, starter cultures technology has been conceived to successfully dominate indigenous microflora and to drive fermentation to foresee the desired attributes of the matrix, assuring quality and safety. Recent trends indicate a general return to spontaneous food fermentation. In this review, we point out the potential risks for human health associated with uncontrolled (uninoculated food fermentation and we discuss biotechnological approaches susceptible to conciliate fermented food safety, with instances of an enhanced contribution of microbes associated to spontaneous fermentation.

STUDY OF THE EFFECTS SHOWN BY THE ACTION OF VARIOUS MICROORGANISMS ON THE LACTIC FERMENTATION OF JUICES

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Iuliana Manea

2010-01-01

Full Text Available Research has established the most effective lactic acid bacteria used for fermentation of fruit and vegetables juices. The cultures were used for Bifidobacteria, Lactobacillus acidophilus and culture of micro flora obtained spontaneous shoots. Lactic fermented juice was obtained from cabbage, carrots and beetroot. Working in these variants were determined lactic fermentation parameters and some of the bioactive compounds from this process: pH, reducing sugars, viable cell counts. Determination of reducing sugars calculated as glucose was conducted using the 3.5 dinitrosalicilic acid method (DNS method, pH was determined with a pH meter electronics. Chemical parameters listed were determined every two hours during the first 24 hours, then 48 and 72 hours in thermostatic conditions at 37 degrees C and 7 days storage at refrigerator temperature. At the end of the lactic fermentation, the lowest pH 4.31, which also provide juice conservation was obtained using a pure culture of Lactobacillus acidophilus. Reducing sugar is metabolized significantly when the juice of beetroot, fermented with Lactobacillus acidophilus culture, 75.19%. The results may be an argument for obtaining juice fermented lactic acid, which are popular functional foods, to obtain a chemical composition and sensory their optimum.

The Effect of Fermentation Time with Probiotic Bacteria on Organic Fertilizer as Daphnia magna Cultured Medium towards Nutrient Quality, Biomass Production and Growth Performance Enhancement

Science.gov (United States)

Endar Herawati, Vivi; Agung Nugroho, Ristiawan; Pinandoyo; Darmanto, YS; Hutabarat, Johannes

2018-02-01

The nutrient quality and growth performance of D. magna are highly depend on the organic fertilizer which is used in its culture medium. The objective of this study was to identify the best fermentation time by using probiotic bacteria on organic fertilizer as mass culture medium to improve its nutrient quality, biomass production, and growth performance. This study was conducted using completely randomized experimental design with five treatments and three repetitions. Organic fertilizers used cultured medium with chicken manure, rejected bread and tofu waste fermented by probiotic bacteria then cultured for 0, 7, 14, 21 and 28 days. The results showed that medium which used 25% chicken manure, 25% tofu waste and 50% rejected bread cultured for 28 days created the highest biomass production, population density and nutrient content of D. magna those are 233,980 ind/L for population density; 134.60 grams for biomass production, 0.574% specific growth rate; 68.06% protein content and 6.91% fat. The highest fatty acid profile is 4.83% linoleic and 3.54% linolenic acid. The highest essential amino acid is 53.94 ppm lysine. In general, the content of ammonia, DO, temperature, and pH during the study were in the good range of D. magna life. The conclusion of this research is medium which used 25% chicken manure, 25% tofu waste and 50% rejected bread cultured for 28 days created the highest biomass production, population and nutrient content of D. magna.

Mixed-culture transcriptome analysis reveals the molecular basis of mixed-culture growth in Streptococcus thermophilus and Lactobacillus bulgaricus

NARCIS (Netherlands)

Sieuwerts, S.; Molenaar, D.; Hijum, van S.A.F.T.; Beerthuyzen, M.; Stevens, M.J.A.; Janssen, P.W.; Ingham, C.J.; Bok, de F.A.M.; Vos, de W.M.; Hylckama Vlieg, van J.E.T.

2010-01-01

Many food fermentations are performed using mixed cultures of lactic acid bacteria. Interactions between strains are of key importance for the performance of these fermentations. Yogurt fermentation by Streptococcus thermophilus and Lactobacillus bulgaricus (basonym, Lactobacillus delbrueckii subsp.

Growth of aspergillus terreus and the production of itaconic acid in batch and continuous cultures. The influence of pH

Energy Technology Data Exchange (ETDEWEB)

Rychtera, M.; Wase, J.D.A.

1981-01-01

Aspergillus terreus (NRRL 1960) was cultivated in batch and in continuous single-stage culture. The influence of pH on the growth of the organism, on the formation of itaconic acid and on the kinetics of fermentation was studied under phosphate limitation, both at controlled ph values and also when the pH was allowed to decrease in a natural way. In the pH range 1.7-3.5, the ratio of undissociated:half-dissociated acid varied from 190:1 to 1.5:1. The amount of completely dissociated acid may be regarded as negligible. In batch systems operated without pH control, an initial pH of 3.1 proved to be the most effective. Product formation under such conditions started at a point where the exponential growth phase commenced and was described by a zero-order equation. The maximum itaconic acid production rate was shifted behind maximum growth rate. The continuous single-stage system was first order with respect to product formation. At pH greater than 3.1, a number of aberrant and pellet forms of the mould occurred, resulting in decreased acid production. (Refs. 41).

Characterization of microbial compositions in a thermophilic chemostat of mixed culture fermentation.

Science.gov (United States)

Zhang, Fang; Yang, Jing-Hua; Dai, Kun; Chen, Yun; Li, Qiu-Rong; Gao, Fa-Ming; Zeng, Raymond J

2016-02-01

The microbial community compositions of a chemostat enriched in a thermophilic (55 °C) mixed culture fermentation (MCF) for hydrogen production under different operational conditions were revealed in this work by integrating denaturing gradient gel electrophoresis (DGGE), Illumina Miseq high-throughput sequencing, and 16S rRNA clone library sequencing. The results showed that the community structure of the enriched cultures was relatively simple. Clones close to the genera of Thermoanaerobacter and/or Bacillus mainly dominated the bacteria. And homoacetogens and archaea were washed out and not detected even by Illumina Miseq high-throughput sequencing which supported the benefit for hydrogen production. On the other hand, the results revealed that the metabolic shift was clearly associated with the change of dominated bacterial groups. The effects of hydrogen partial pressure (PH2) and pH from 4.0 to 5.5 on the microbial compositions were not notable and Thermoanaerobacter was dominant, thus, the metabolites were also not changed. While Bacillus, Thermoanaerobacter and Propionispora hippei dominated the bacteria communities at neutral pH, or Bacillus and Thermoanaerobacter dominated at high influent glucose concentrations, consequently the main metabolites shifted to acetate, ethanol, propionate, or lactate. Thereby, the effect of microbial composition on the metabolite distribution and shift shall be considered when modeling thermophilic MCF in the future.

Chemical oxygen demand reduction in a whey fermentation

Energy Technology Data Exchange (ETDEWEB)

Moresi, M; Colicchio, A; Sansovini, F; Sebastiani, E

1980-01-01

The efficiency of COD reduction in the fermentation of whey by Kluyveromyces fragilis IMAT 1872 was studied at various temperatures, lactose concentrations, air dilution ratios, and stirring speeds. Two different optimal sets of these variables were found according to whether the objective was the production of cell mass or the reduction of COD. The 2 sets were then compared to establish a strategy for the industrial development of this fermentation process. The experimental efficiencies of COD removal were submitted to analysis in a composite design. Only the O2 transfer coefficient factor and the stripping factor were significant. Therefore, the observations were fitted with a quadratic expression by using only these factors: the mean std. error was <6%. The yield of cells varied in this fermentation, but this parameter may be particularly useful for analyzing and optimizing any fermentation process when the culture medium is a mixture of carbohydrates or the main substrate is fully utilized during the initial stages of fermentation.

Influence of physiological state of inoculum on volatile acidity production by Saccharomyces cerevisiae during high sugar fermentation

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Marina Bely

2005-12-01

Full Text Available An approach consisting of controlling yeast inoculum to minimize volatile acidity production by Saccharomyces cerevisiae during the alcoholic fermentation of botrytized must was investigated. Direct inoculation of rehydrated active dry yeasts produced the most volatile acidity, while a yeast preparation pre-cultured for 24 hours reduced the final production by up to 23 %. Using yeasts collected from a fermenting wine as a starter must also reduced volatile acidity production. The conditions for preparing the inoculum affected the fermentation capacity of the first generation yeasts: fermentation duration, sugar to ethanol ratio, and wine composition. A pre-culture medium with a low sugar concentration (< 220 g/L is essential to limit volatile acidity production in high sugar fermentations.

Technical paper on the realisation of a continuous axenic culture of chlorella. Description of a biostat; Note technique sur la realisation d'une culture continue et axenique de chlorelles. Description d'un biostat

Energy Technology Data Exchange (ETDEWEB)

Dalmon, J; Gilet, R [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1966-07-01

An apparatus for the continuous cultivation of chlorella is described with the means that allowed to keep axenic cultures for several months. (authors) [French] On decrit un appareil assurant une culture continue de chlorelles en insistant sur les modalites qui permettent de garder cette culture axenique durant plusieurs mois. (auteurs)

Ruminal fermentation of Anti-methanogenic Nitrate- and Nitro-Containing Forages In Vitro

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Robin C. Anderson

2016-08-01

Full Text Available Nitrate, 3-nitro-1-propionic acid (NPA and 3-nitro-1-propanol (NPOH can accumulate in forages and be poisonous to animals if consumed in high enough amounts. These chemicals are also recognized as potent anti-methanogenic compounds, but plants naturally containing these chemicals have been studied little in this regard. Presently, we found that nitrate-, NPA- or NPOH-containing forages effectively decreased methane production, by 35 to 87%, during in vitro fermentation by mixed cultures of ruminal microbes compared to fermentation by cultures incubated similarly with alfalfa. Methane production was further decreased during incubation of mixed cultures also inoculated with Denitrobacterium detoxificans, a ruminal bacterium known to metabolize nitrate, NPA and NPOH. Inhibition of methanogens within the mixed cultures was greatest with the NPA- and NPOH-containing forages. Hydrogen accumulated in all the mixed cultures incubated with forages containing nitrate, NPA or NPOH but was dramatically higher, exceeding 40 µmol hydrogen/mL, in mixed cultures incubated with NPA-containing forage but not inoculated with D. detoxificans. This possibly reflects the inhibition of hydrogenase-catalyzed uptake of hydrogen produced via conversion of 50 µmol added formate per mL to hydrogen. Accumulations of volatile fatty acids revealed compensatory changes in fermentation in mixed cultures incubated with the nitrate-, NPA- and NPOH-containing forages as evidenced by lower accumulations of acetate, and in some cases higher accumulations of butyrate and lower accumulations of ammonia, iso-buytrate and iso-valerate compared to cultures incubated with alfalfa. Results reveal that nitrate, NPA and NPOH that accumulate naturally in forages can be made available within ruminal incubations to inhibit methanogenesis. Further research is warranted to determine if diets can be formulated with nitrate-, NPA- and NPOH-containing forages to achieve efficacious mitigation in

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

Science.gov (United States)

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.

Effects of feedstock and co-culture of Lactobacillus fermentum and wild Saccharomyces cerevisiae strain during fuel ethanol fermentation by the industrial yeast strain PE-2.

Science.gov (United States)

Reis, Vanda R; Bassi, Ana Paula G; Cerri, Bianca C; Almeida, Amanda R; Carvalho, Isis G B; Bastos, Reinaldo G; Ceccato-Antonini, Sandra R

2018-02-16

Even though contamination by bacteria and wild yeasts are frequently observed during fuel ethanol fermentation, our knowledge regarding the effects of both contaminants together is very limited, especially considering that the must composition can vary from exclusively sugarcane juice to a mixture of molasses and juice, affecting the microbial development. Here we studied the effects of the feedstock (sugarcane juice and molasses) and the co-culture of Lactobacillus fermentum and a wild Saccharomyces cerevisiae strain (rough colony and pseudohyphae) in single and multiple-batch fermentation trials with an industrial strain of S. cerevisiae (PE-2) as starter yeast. The results indicate that in multiple-cycle batch system, the feedstock had a minor impact on the fermentation than in single-cycle batch system, however the rough yeast contamination was more harmful than the bacterial contamination in multiple-cycle batch fermentation. The inoculation of both contaminants did not potentiate the detrimental effect in any substrate. The residual sugar concentration in the fermented broth had a higher concentration of fructose than glucose for all fermentations, but in the presence of the rough yeast, the discrepancy between fructose and glucose concentrations were markedly higher, especially in molasses. The biggest problem associated with incomplete fermentation seemed to be the lower consumption rate of sugar and the reduced fructose preference of the rough yeast rather than the lower invertase activity. Lower ethanol production, acetate production and higher residual sugar concentration are characteristics strongly associated with the rough yeast strain and they were not potentiated with the inoculation of L. fermentum.

Persistence of Escherichia coli O157:H7 in dairy fermentation systems.

Science.gov (United States)

Dineen, S S; Takeuchi, K; Soudah, J E; Boor, K J

1998-12-01

We examined (i) the persistence of Escherichia coli O157:H7 as a postpasteurization contaminant in fermented dairy products; (ii) the ability of E. coli O157:H7 strains with and without the general stress regulatory protein, RpoS, to compete with commercial starter cultures in fermentation systems; and (iii) the survival of E. coli O157:H7 in the yogurt production process. In commercial products inoculated with 10(3) CFU/ml, E. coli O157:H7 was recovered for up to 12 days in yogurt (pH 4.0), 28 days in sour cream (pH 4.3), and at levels > 10(2) CFU/ml at 35 days in buttermilk (pH 4.1). For the starter culture competition trials, the relative inhibition of E. coli O157:H7 in the experimental fermentation systems was, in decreasing order, thermophilic culture mixture, Lactobacillus delbrueckii subsp. bulgaricus R110 alone, Lactococcus lactis subsp. lactis D280 alone, Lactococcus lactis subsp. cremoris D62 alone, and Streptococcus thermophilus C90 alone showing the least inhibition. Recovery of the rpoS mutant was lower than recovery of its wild-type parent by 72 h or earlier in the presence of individual starter cultures. No E. coli O157:H7 were recovered after the curd formation step in yogurt manufactured with milk inoculated with 10(5) CFU/ml. Our results show that (i) postprocessing entry of E. coli O157:H7 into fermented dairy products represents a potential health hazard; (ii) commercial starter cultures differ in their ability to reduce E. coli O157:H7 CFU numbers in fermentation systems; and (iii) the RpoS protein appears to most effectively contribute to bacterial survival in the presence of conditions that are moderately lethal to the cell.

Fermentation and storage of probiotic yoghurt from goat’s milk

OpenAIRE

Rajka Božanić; Irena Rogelj; Ljubica Tratnik

2002-01-01

Cow’s and goat’s milk supplemented with inulin were fermented withABT4 culture. The population growth of Streptococcus thermophilus,Lactobacillus acidophilus and Bifidobacterium ssp. in plain and inulinsupplemented goat’s milk during fermentation was evaluated. The survival of strains during 28 d of storage was followed in comparison with that of cow’s milk. The time required to reach the desired pH of 4.6 during fermentation was 6 h for both types of milk. At that time the proportion of viab...

Kinetics model development of cocoa bean fermentation

Science.gov (United States)

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.

Microbiological Hydrogen Production by Anaerobic Fermentation and Photosynthetic Process

International Nuclear Information System (INIS)

Asada, Y.; Ohsawa, M.; Nagai, Y.; Fukatsu, M.; Ishimi, K.; Ichi-ishi, S.

2009-01-01

Hydrogen gas is a clean and renewable energy carrier. Microbiological hydrogen production from glucose or starch by combination used of an anaerobic fermenter and a photosynthetic bacterium, Rhodobacter spheroides RV was studied. In 1984, the co-culture of Clostridium butyricum and RV strain to convert glucose to hydrogen was demonstrated by Miyake et al. Recently, we studied anaerobic fermentation of starch by a thermophilic archaea. (Author)

Sustainable fermentative hydrogen production: challenges for process optimisation

Energy Technology Data Exchange (ETDEWEB)

Hawkes, F.R.; Dinsdale, R. [University of Glamorgan, Pontypridd (United Kingdom). School of Applied Sciences; Hawkes, D.L.; Hussy, I. [University of Glamorgan, Pontypridd (United Kingdom). School of Technology

2002-12-01

This paper reviews information from continuous laboratory studies of fermentative hydrogen production useful when considering practical applications of the technology. Data from reactors operating with pure cultures and mixed microflora enriched from natural sources are considered. Inocula have been derived from heat-treated anaerobically digested sludge, activated sludge, aerobic compost and soil, and non-heat-treated aerobically composted activated sludge. Most studies are on soluble defined substrates, and there are few reports of continuous operation on complex substrates with mixed microflora to produce H{sub 2}. Methanogenesis which consumes H{sub 2} may be prevented by operation at short hydraulic retention times (around 8-12 h on simple substrates) and/or pH below 6. Although the reactor technology for anaerobic digestion and biohydrogen production from complex substrates may be similar, there are important microbiological differences, including the need to manage spore germination and oxygen toxicity on start-up and control sporulation in adverse circumstances during reactor operation. (Author)

Indigenous Saccharomyces cerevisiae yeasts as a source of biodiversity for the selection of starters for specific fermentations

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Capece Angela

2014-01-01

Full Text Available The long-time studies on wine yeasts have determined a wide diffusion of inoculated fermentations by commercial starters, mainly of Saccharomyces. Although the use of starter cultures has improved the reproducibility of wine quality, the main drawback to this practice is the lack of the typical traits of wines produced by spontaneous fermentation. These findings have stimulated wine-researchers and wine-makers towards the selection of autochthonous strains as starter cultures. The objective of this study was to investigate the biodiversity of 167 S. cerevisiae yeasts, isolated from spontaneous fermentation of grapes. The genetic variability of isolates was evaluated by PCR amplification of inter-δ region with primer pair δ2/δ12. The same isolates were investigated for characteristics of oenological interest, such as resistance to sulphur dioxide, ethanol and copper and hydrogen sulphide production. On the basis of technological and molecular results, 20 strains were chosen and tested into inoculated fermentations at laboratory scale. The experimental wines were analyzed for the content of some by-products correlated to wine aroma, such as higher alcohols, acetaldehyde, ethyl acetate and acetic acid. One selected strain was used as starter culture to perform fermentation at cellar level. The selection program followed during this research project represents an optimal combination between two different trends in modern winemaking: the use of S. cerevisiae as starter cultures and the starter culture selection for specific fermentations.

The economics of ethanol production by extractive fermentation

Energy Technology Data Exchange (ETDEWEB)

Daugulis, A J; Axford, D B; McLellan, P J [Queen' s Univ., Kingston, ON (Canada)

1991-04-01

Extractive fermentation is a processing strategy in which reaction and recovery occur simultaneously in a fermentation vessel through the use of a water-immiscible solvent which selectively removes an inhibitory product. An ethanol-extractive fermentation process has been developed, incorporating continuous operation and the ability to ferment concentrated feedstocks. A detailed economic assessment of this process is provided relative to current technology for an annual capacity of 100 million litres of ethanol. Extractive fermentation provides significant economic advantages for both grass roots and retrofitted plants. Total production costs are estimated at 45{cents}/l for a conventional plant and 29.4{cents}/l for a retrofitted plant. The main cost saving achievable by extractive fermentation is in energy, used for evaporation and drying, since the process uses significantly less water in its conversion of concentrated feedstocks. Producing anhydrous ethanol without distillation is also a prospect. 15 refs., 5 fig., 10 tabs.

Microbiological Characteristics of Trachanas, a Traditional Fermented Dairy Product from Cyprus

OpenAIRE

Bozoudi, Despina; Agathokleous, Maria; Anastasiou, Iacovos; Papademas, Photis; Tsaltas, Dimitris

2017-01-01

The purpose of this study was to characterize the autochthonous microbiota of Cypriot Trachanas, a traditional fermented ewes’ milk product. For this reason, 12 samples of raw and fermented milk as well as natural starter culture were collected in order to count, isolate, and identify the main species present during Trachanas fermentation. In total, 198 colonies were retrieved and 163 were identified by sequencing analysis at species level. Lactic acid bacteria (LAB) were the predominant grou...

Growth and Survival Rate of Tilapia (Oreochromis niloticus Larvae Fed by Daphnia magna Cultured With Organic Fertilizer Resulted From Probiotic Bacteria Fermentation

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Vivi Endar Herawati

2015-10-01

Full Text Available Daphnia magna is a potential feed for fish. The aim of this research was to find the best treatment and effect of D. magna culture addition from fermented organic fertilizer, to growth and survival rate of Oreochromis niloticus larvae. There were five treatments, each with three repetitions used in the study. All treatments used chicken dung, and different combinations of rice bran, coconut oilcake waste and tilapia larvae. Feeding on tilapia was given by ad libitum method for five times a day until 14 days. Water quality during the research was maintained at temperature 28–29°C, DO 0.3 ppm and pH 8.1–8.2. Observed variables include relative growth rate, survival rate, food consumption rate and water quality. Our results showed that D. magna cultured by fermented organic fertilizer for tilapia larvae (O. niloticus had high significant effect (p < 0.01 on the relative growth rate and survival rate. Treatment of D. magna cultured by 1.2 g/L chicken manure, 0.9 g/L rice bran and 0.3 g/L coconut oilcake showed the highest value on the relative growth rate (10.86%; survival rate (98.46% and food consumption at first week (106.43% and second week (152.76%.

In vitro digestibility of processed and fermented soya bean, cowpea and maize

NARCIS (Netherlands)

Kiers, J.L.; Nout, M.J.R.; Rombouts, F.M.

2000-01-01

Tropical legumes, ie soya bean and cowpea, were pre-treated and subsequently fermented using pure cultures of Rhizopus spp. Impact of soaking, cooking and fermentation of the legumes on their digestibility was determined using an in vitro digestion method. Processing of white maize included, amongst

Continuous fermentation using low concentration of sugar cane and Zymomonas mobilis CP4 for ethanol production

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João Batista Buzato

2001-01-01

Full Text Available Effect of dilution rate in continuous fermentation of 20g sucrose/L and Z. mobilis CP4 was studied for ethanol production at 28oC + 1, without pH control. Four dilution rates were compared: 0.045; 0.14; 0.23 and 0.34 h-1. In dilution rates 0.045; 0.14 and 0.23 h-1 were produced 9,4g/L of ethanol and in dilution rate 0.34 h-1 was produced 8,8 g/L. Ethanol conversion efficiency were of 91% in dilution rates 0.045; 0.14 and 0. 23 h-1. In dilution rate 0.34 h-1 the conversion efficiency was of 85%.

Proteomic profiling of an undefined microbial consortium cultured in fermented dairy manure: Methods development.

Science.gov (United States)

Hanson, Andrea J; Paszczynski, Andrzej J; Coats, Erik R

2016-03-01

The production of polyhydroxyalkanoates (PHA; bioplastics) from waste or surplus feedstocks using mixed microbial consortia (MMC) and aerobic dynamic feeding (ADF) is a growing field within mixed culture biotechnology. This study aimed to optimize a 2DE workflow to investigate the proteome dynamics of an MMC synthesizing PHA from fermented dairy manure. To mitigate the challenges posed to effective 2DE by this complex sample matrix, the bacterial biomass was purified using Accudenz gradient centrifugation (AGC) before protein extraction. The optimized 2DE method yielded high-quality gels suitable for quantitative comparative analysis and subsequent protein identification by LC-MS/MS. The optimized 2DE method could be adapted to other proteomic investigations involving MMC in complex organic or environmental matrices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Proteolytic activity of selected moulds in the first fermentation of black-seeded soysauce

Science.gov (United States)

Yulifianti, R.; Ginting, E.

2018-01-01

Black-seeded soybean is preferred as normally it has higher protein content and would give black colour to the soyfiltrate for making soysauce. Mould is usually used in the first fermentation of soysauce making to prepare koji with high soluble protein as a media for the subsequent bacteria fermentation in brine solution. Black-seeded soybean of Detam 1 variety was used as the soysauce ingredient. The trial was a randomized complete design with four replicates. The treatments were (1) Rhizopus oligosporus starter (in flour form) with two day-fermentation, (2) similar R. oligosporus starter with three-day fermentation, (3) Aspergillus sojae (pure culture) with three-day fermentation and (4) A. sojae in flour form with three-day fermentation. The black-seeded soybean had 100-grain weight of 11.7 g, high protein content of 42.5% dw and fat content of 14.9% dw. Koji prepared using R. oligosporus starter with two-day fermentation had the lowest protein content (48.9% dw). Both starters of A. sojae culture and flour gave the highest soluble protein content of koji (41.0-41.5% dw), followed by R. oligosporus starter with 3 day-fermentation (35.2% dw). Whilst the lowest value was noted in koji prepared using R. oligosporus starter with two day-fermentation (30.8% dw). This suggests that both A. sojae starters had similar proteolitic activity and higher than that of R. oligosporus starter. In terms of practical application and maintenance of the mould viability by soysauce processors, the use of A. sojae flour starter with three-day fermentation is suggested.

The pentose moiety of adenosine and inosine is an important energy source for the fermented-meat starter culture Lactobacillus sakei CTC 494.

Science.gov (United States)

Rimaux, T; Vrancken, G; Vuylsteke, B; De Vuyst, L; Leroy, F

2011-09-01

The genome sequence of Lactobacillus sakei 23K has revealed that the species L. sakei harbors several genes involved in the catabolism of energy sources other than glucose in meat, such as glycerol, arginine, and nucleosides. In this study, a screening of 15 L. sakei strains revealed that arginine, inosine, and adenosine could be used as energy sources by all strains. However, no glycerol catabolism occurred in any of the L. sakei strains tested. A detailed kinetic analysis of inosine and adenosine catabolism in the presence of arginine by L. sakei CTC 494, a fermented-meat starter culture, was performed. It showed that nucleoside catabolism occurred as a mixed-acid fermentation in a pH range (pH 5.0 to 6.5) relevant for sausage fermentation. This resulted in the production of a mixture of acetic acid, formic acid, and ethanol from ribose, while the nucleobase (hypoxanthine and adenine in the case of fermentations with inosine and adenosine, respectively) was excreted into the medium stoichiometrically. This indicates that adenosine deaminase activity did not take place. The ratios of the different fermentation end products did not vary with environmental pH, except for the fermentation with inosine at pH 5.0, where lactic acid was produced too. In all cases, no other carbon-containing metabolites were found; carbon dioxide was derived only from arginine catabolism. Arginine was cometabolized in all cases and resulted in the production of both citrulline and ornithine. Based on these results, a pathway for inosine and adenosine catabolism in L. sakei CTC 494 was presented, whereby both nucleosides are directly converted into their nucleobase and ribose, the latter entering the heterolactate pathway. The present study revealed that the pentose moiety (ribose) of the nucleosides inosine and adenosine is an effective fermentable substrate for L. sakei. Thus, the ability to use these energy sources offers a competitive advantage for this species in a meat environment.

COMPARATIVE EVALUTION OF CEPHALOSPORIN-C PRODUCTION IN SOLID STATE FERMENTATION AND SUBMERGED LIQUID CULTURE

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Mahdi Rezazarandi

2012-08-01

Full Text Available The advantages of solid state fermentation (SSF utilization in producing enzymes & secondary metabolites have been shown, whereas, submerged liquid fermentation (SLF condition has the major usage in industrial production of antibiotics. As an antibiotic of B-lactams group, cephalosporin-C (CPC is indicated due to its wide effect and broad convention in treatment of infectious diseases. Regarding industrial production of CPC regularly done in SLF condition, we compared CPC production sum in SLF and SSF conditions. In this analysis, A. chrysogenum was employed, which was inoculated to SLF and SSF, while internal fermenter conditions were totally under control. After extraction of CPC, productions in two states of SLF and SSF were compared using the cylinder plate method. According to Antibiotic assay and production amount comparison, results expressed a ratio of development of production in SSF conditions to SLF conditions. Regarding previous studies on a solid state fermenter and its advantages, in this study, convenience of SSF conditions compared to SLF conditions was experimented. Also mentioning that maintaining the condition of solid state fermenter is more comfortable and practical than liquid state fermenter, using a solid based fermenter to produce antibiotics, especially CPC, can be appropriate. Considering appropriate control conditions of SSF to produce secondary metabolites, decrease in expenses, and increase of production, taking advantage of it in order to increase production parallel to modern methods, such as genetically manipulating CPC producing microorganisms are recommended to pharmacological industries. Also, to make this method applicable, further studies in industrial criterion seem necessary.

Implementation of Mobile Pedagogy During Continuous Education of Physical Culture Teachers

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Roman S.

2018-03-01

Full Text Available Introduction: one of the urgent problems in the field of continuous training of future teachers of physical culture is the training of students using mobile devices and innovative educational Internet technologies. The scientific literature has thoroughly studied the introduction of mobile technologies in the professional training of teachers, but the development of foundations for the formation of physical competence based on innovative approaches, such as mobile training, has not been implemented to date. Hence, the necessity of setting the research goal that is to create a methodological model for the continuing education of teachers of physical culture on the basis of the ideas of mobile pedagogy in the cluster “college - university” and the use of experimental methods to substantiate the effectiveness of its implementation in the professional training of students. Materials and Methods: to create a model of continuous education, including the integration of various clusters, components and innovative technologies, the systemic approach is applied to the study with the additional use of competency, activity, qualification, personality-orientedness, culturological and innovation-technological approaches. Systematisation, comparison, comparison and generalisation are used in modeling the continuous education of teachers of physical culture. Results: in the process of research, the integrating resources and the scientific and educational potential of secondary and higher education were revealed. These recourses allowed the systematisation and modeling of the process of continuing education of teachers of physical culture based on the ideas of mobile pedagogy in the cluster “college - university”. At the experimental stage of the study, the effectiveness of the implementation of mobile pedagogy is proved and the author’s approach to the training of future teachers of physical culture is methodologically grounded. Discussion and

Controlled mixed fermentation at winery scale using Zygotorulaspora florentina and Saccharomyces cerevisiae.

Science.gov (United States)

Lencioni, Livio; Romani, Cristina; Gobbi, Mirko; Comitini, Francesca; Ciani, Maurizio; Domizio, Paola

2016-10-03

Over the last few years the use of multi-starter inocula has become an attractive biotechnological practice in the search for wine with high flavour complexity or distinctive characters. This has been possible through exploiting the particular oenological features of some non-Saccharomyces yeast strains, and the effects that derive from their specific interactions with Saccharomyces. In the present study, we evaluated the selected strain Zygotorulaspora florentina (formerly Zygosaccharomyces florentinus) in mixed culture fermentations with Saccharomyces cerevisiae, from the laboratory scale to the winery scale. The scale-up fermentation and substrate composition (i.e., white or red musts) influenced the analytical composition of the mixed fermentation. At the laboratory scale, mixed fermentation with Z. florentina exhibited an enhancement of polysaccharides and 2-phenylethanol content and a reduction of volatile acidity. At the winery scale, different fermentation characteristics of Z. florentina were observed. Using Sangiovese red grape juice, sequential fermentation trials showed a significantly higher concentration of glycerol and esters while the sensorial analysis of the resulting wines showed higher floral notes and lower perception of astringency. To our knowledge, this is the first time that this yeasts association has been evaluated at the winery scale indicating the potential use of this mixed culture in red grape varieties. Copyright © 2016. Published by Elsevier B.V.

PUSAKA SAUJANA BOROBUDUR: PERUBAHAN DAN KONTINUITASNYA (Borobudur Cultural Landscape: Change and Continuity