Ethanol Fermentation of Various Pretreated and Hydrolyzed Substrates at Low Initial pH

Science.gov (United States)

Kádár, Zsófia; Maltha, San Feng; Szengyel, Zsolt; Réczey, Kati; de Laat, Wim

Lignocellulosic materials represent an abundant feedstock for bioethanol production. Because of their complex structure pretreatment is necessary to make it accessible for enzymatic attack. Steam pretreatment with or without acid catalysts seems to be one of the most promising techniques, which has already been applied for large variety of lignocellulosics in order to improve enzymatic digestibility. During this process a range of toxic compounds (lignin and sugar degradation products) are formed which inhibit ethanol fermentation. In this study, the toxicity of hemicellulose hydrolysates obtained in the steam pretreatment of spruce, willow, and corn stover were investigated in ethanol fermentation tests using a yeast strain, which has been previously reported to have a resistance to inhibitory compounds generated during steam pretreatment. To overcome bacterial contamination, fermentations were carried out at low initial pH. The fermentability of hemicellulose hydrolysates of pretreated lignocellulosic substrates at low pH gave promising results with the economically profitable final 5 vol% ethanol concentration corresponding to 85% of theoretical. Adaptation experiments have shown that inhibitor tolerance of yeast strain can be improved by subsequent transfer of the yeast to inhibitory medium.

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.

Improving properties of sweet potato composite flour: Influence of lactic fermentation

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Yuliana, Neti; Nurdjanah, Siti; Setyani, Sri; Novianti, Dini

2017-06-01

The use of locally grown crops such as sweet potato as raw material for composite flour is considered advantageous as it reduces the importation of wheat flour. However the use of native sweetpotato flour has drawback properties when applied in the food. This study was aimed to modify sweet potato flour through six methods of lactic fermentation (spontaneous, pickle brine, Lb plantarum, Lc mesentereoides, a mixed of Lb plantarum and Lc mesentereoides, and mixed of Lb plantarum, Lc mesentereoides and yeast) to increase its properties in composite flour. Composite flours were obtained after fermentation of sweet potato slices for 48h in the proportion of 50% sweet potatoes flour and 50% wheat flour. pH, moisture content, swelling power, solubility, and pasting properties were determined for the fermented and unfermented composite flours. The results indicated that the composite fermented flours had better properties than those of non fermented flour. Fermentation increased swelling power, moisture content, meanwhile, solubility, and pH, deacresed. Amylose leaching, however, was not significantly affected by the fermentation process.

Low fermentation pH is a trigger to alcohol production, but a killer to chain elongation

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Ramon eGanigué

2016-05-01

Full Text Available Gasification of organic wastes coupled to syngas fermentation allows the recovery of carbon in the form of commodity chemicals, such as carboxylates and biofuels. Acetogenic bacteria ferment syngas to mainly two-carbon compounds, although a few strains can also synthesize four-, and six-carbon molecules. In general, longer carbon chain products have a higher biotechnological (and commercial value due to their higher energy content and their lower water solubility. However, de-novo synthesis of medium-chain products from syngas is quite uncommon in bacteria. An alternative to de-novo synthesis is bioproduction of short-chain products (C2 and C4, and their subsequent elongation to C4, C6 or C8 through reversed β-oxidation metabolism. This two-step synergistic approach has been successfully applied for the production of up to C8 compounds, although, the accumulation of alcohols in these mixed cultures remained below detection limits. The present work investigates the production of higher alcohols from syngas by open mixed cultures (OMC. A syngas-fermenting community was enriched from sludge of an anaerobic digester for a period of 110 days in a lab-scale reactor. At the end of this period, stable production of ethanol and butanol was obtained. C6 compounds were only transiently produced at the beginning of the enrichment phase, during which Clostridium kluyveri, a bacterium able to carry out carbon chain elongation, was detected in the community. Further experiments showed pH as a critical parameter to maintain chain elongation activity in the co-culture. Production of C6 compounds was recovered by preventing fermentation pH to decrease below pH 4.5-5. Finally, experiments showed maximal production of C6 compounds (0.8 g/L and alcohols (1.7 g/L of ethanol, 1.1 g/L of butanol and 0.6 g/L of hexanol at pH 4.8. In conclusion, low fermentation pH is critical for the production of alcohols, although detrimental to C. kluyveri. Fine control of

Influence of trace elements mixture on bacterial diversity and fermentation characteristics of liquid diet fermented with probiotics under air-tight condition.

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Yuyong He

Full Text Available Cu2+, Zn2+, Fe2+ and I- are often supplemented to the diet of suckling and early weaning piglets, but little information is available regarding the effects of different Cu2+, Zn2+, Fe2+ and I- mixtures on bacteria growth, diversity and fermentation characteristics of fermented liquid diet for piglets. Pyrosequencing was performed to investigate the effect of Cu2+, Zn2+, Fe2+ and I- mixtures on the diversity, growth and fermentation characteristics of bacteria in the liquid diet fermented with Bacillus subtilis and Enterococcus faecalis under air-tight condition. Results showed that the mixtures of Cu2+, Zn2+, Fe2+ and I- at different concentrations promoted Bacillus growth, increased bacterial diversity and lactic acid production and lowered pH to about 5. The importance of Cu2+, Zn2+, Fe2+ and I- is different for Bacillus growth with the order Zn2+> Fe2+>Cu2+> I- in a 21-d fermentation and Cu2+>I->Fe2+>Zn2+ in a 42-d fermentation. Cu2+, Zn2+, Fe2+ and I- is recommended at a level of 150, 60, 150 and 0.6 mg/kg respectively for the production of fermented liquid diet with Bacillus subtilis. The findings improve our understanding of the influence of trace elements on liquid diet fermentation with probiotics and support the proper use of trace elements in the production of fermented liquid diet for piglets.

Enhancement of hydrogen production during waste activated sludge anaerobic fermentation by carbohydrate substrate addition and pH control.

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Chen, Yinguang; Xiao, Naidong; Zhao, Yuxiao; Mu, Hui

2012-06-01

The effects of carbohydrate/protein ratio (CH/Pr) and pH on hydrogen production from waste activated sludge (WAS) were investigated. Firstly, the optimal pH value for hydrogen production was influenced by the CH/Pr ratio, which was pH 10, 9, 8, 8, 8 and 6 at the CH/Pr ratio (COD based) of 0.2 (sole sludge), 1, 2.4, 3.8, 5 and 6.6, respectively. The maximal hydrogen production (100.6 mL/g-COD) was achieved at CH/Pr of 5 and pH 8, which was due to the synergistic effect of carbohydrate addition on hydrogen production, the enhancement of sludge protein degradation and protease and amylase activities, and the suitable fermentation pathway for hydrogen production. As hydrogen consumption was observed at pH 8, in order to further increase hydrogen production a two-step pH control strategy (pH 8+pH 10) was developed and the hydrogen production was further improved by 17.6%. Copyright © 2012 Elsevier Ltd. All rights reserved.

Modeling of acetate-type fermentation of sugar-containing wastewater under acidic pH conditions.

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Huang, Liang; Pan, Xin-Rong; Wang, Ya-Zhou; Li, Chen-Xuan; Chen, Chang-Bin; Zhao, Quan-Bao; Mu, Yang; Yu, Han-Qing; Li, Wen-Wei

2018-01-01

In this study, a kinetic model was developed based on Anaerobic Digestion Model No. 1 to provide insights into the directed production of acetate and methane from sugar-containing wastewater under low pH conditions. The model sufficiently described the dynamics of liquid-phase and gaseous products in an anaerobic membrane bioreactor by comprehensively considering the syntrophic bioconversion steps of sucrose hydrolysis, acidogenesis, acetogenesis and methanogenesis under acidic pH conditions. The modeling results revealed a significant pH-dependency of hydrogenotrophic methanogenesis and ethanol-producing processes that govern the sucrose fermentative pathway through changing the hydrogen yield. The reaction thermodynamics of such acetate-type fermentation were evaluated, and the implications for process optimization by adjusting the hydraulic retention time were discussed. This work sheds light on the acid-stimulated acetate-type fermentation process and may lay a foundation for optimization of resource-oriented processes for treatment of food wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fermentation of aqueous plant seed extracts by lactic acid bacteria

Energy Technology Data Exchange (ETDEWEB)

Schafner, D.W.; Beuchat, R.L.

1986-05-01

The effects of lactic acid bacterial fermentation on chemical and physical changes in aqueous extracts of cowpea (Vigna unguiculata), peanut (Arachis hypogea), soybean (Glycine max), and sorghum (Sorghum vulgare) were studied. The bacteria investigated were Lactobacillus helveticus, L. delbrueckii, L. casei, L. bulgaricus, L. acidophilus, and Streptococcus thermophilus. Organisms were inoculated individually into all of the seed extracts; L. bulgaricus and S. thermophilus were also evaluated together as inocula for fermenting the legume extracts. During fermentation, bacterial population and changes in titratable acidity, pH, viscosity, and color were measured over a 72 h period at 37 degrees C. Maximum bacterial populations, titratable acidity, pH, and viscosity varied depending upon the type of extract and bacterial strain. The maximum population of each organism was influenced by fermentable carbohydrates, which, in turn, influenced acid production and change in pH. Change in viscosity was correlated with the amount of protein and titratable acidity of products. Color was affected by pasteurization treatment and fermentation as well as the source of extract. In the extracts inoculated simultaneously with L. bulgaricus and S. thermophilus, a synergistic effect resulted in increased bacterial populations, titratable acidity, and viscosity, and decreased pH in all the legume extracts when compared to the extracts fermented with either of these organisms individually. Fermented extracts offer potential as substitutes for cultured dairy products. 24 references.

Influence of black tea concentrate on kombucha fermentation

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Malbaša Radomir V.

2006-01-01

Full Text Available Kombucha is cultivated on substrates prepared with different concentrations of black tea and substrate obtained by diluting a substrate with highest concentration of black tea with cold tap water. Qualify of produced beverages is compared with the beverage obtained in traditional fermentation of 1.5 g/L of black tea, sweetened with 70 g/L of sucrose. Inoculation was performed with 10% (v/v of fermentation liquid from previous process, and the fermentation was carried out at 28°C under aerobic conditions, for ten days. Process of fermentation was monitored by following pH, total acids. D-gluconic acid and caffeine content. Beverages obtained in fermentation with diluted black tea concentrate had similar amounts of investigated metabolites compared with traditional one. Use of diluted black tea concentrate as a substrate needs the shorter time for the substrate preparation, which significantly saves energy.

Effects of Two-stage Controlled pH and Temperature vs. One-step Process for Hemicellulase Biosynthesis and Feruloyl Oligosaccharide Fermentation using Aureobasidium pullulans

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Xiaohong Yu

2016-04-01

Full Text Available A two-stage, pH- and temperature-controlled wheat bran fermentation method using Aureobasidium pullulans was investigated for feruloyl oligosaccharides (FOs production and the activities of xylanase, xylosidase, and ferulic acid esterase (FAE. A. pullulans secreted xylanase, xylosidase, and FAE at high levels in the initial pH of 4.0 to 5.0 and a fermentation liquid temperature of 31 °C to 33 °C. FOs production via two-stage fermentation (FOs 2 reached 1123 nmol/L after fermentation for 96 h, by controlling the initial pH at 4.0 and the initial temperature at 33 °C, and then changing the pH to 6.0 and the temperature to 29 °C at the same time at 36 h. This process was 12 h shorter and 219 nmol/L higher than a one-stage fermentation for producing FOs 1. Xylanase, xylosidase, and FAE activities were highly correlated with controlled pH and temperature and FOs biosynthesis rate. Thus, the combination of two-stage controlled pH and temperature could support mass production of FOs.

Variations of internal pH in typical Italian sourdough yeasts during co-fermentation with lactobacilli

DEFF Research Database (Denmark)

Valmorri, Sara; Mortensen, Henrik Dam; Jespersen, Lene

2008-01-01

The effects of organic acids (lactic and acetic) and extracellular pH (pHex) on the intracellular pH (pHi) of Saccharomyces cerevisiae and Candida milleri during co-fermentation with lactobacilli were investigated by using Fluorescence-Ratio-Imaging-Microscopy (FRIM). Yeasts were grown in a syste...

Influence of Fermentation Methods on Neutral Detergent Fiber Degradation Parameters

DEFF Research Database (Denmark)

Bossen, D; Mertens, D R; Weisbjerg, M R

2008-01-01

The effect of 3 fermentation methods, in situ (IS) in 4 lactating cows (average pH of 5.8), in vitro (IVn) with media pH of 6.8, or in vitro (IVa) with media pH adjusted to 6.0 using citric acid, on fiber degradation parameters was studied using feeds ground to different particle sizes. Corn silage...

Influence of Lactobacillus plantarum on yogurt fermentation properties and subsequent changes during postfermentation storage.

Science.gov (United States)

Li, Changkun; Song, Jihong; Kwok, Lai-Yu; Wang, Jicheng; Dong, Yan; Yu, Haijing; Hou, Qiangchuan; Zhang, Heping; Chen, Yongfu

2017-04-01

This study aimed to evaluate the influence of 9 Lactobacillusplantarum with broad-spectrum antibacterial activity on fermented milk, including changes to the fermentation characteristics (pH, titration acidity, and viable counts), texture profile, relative content of volatile compounds, and sensory evaluation during 28-d storage at 4°C. First, L. plantarum IMAU80106, IMAU10216, and IMAU70095 were selected as candidates for further study because of their excellent coagulation and proteolytic activities. Subsequently, these L. plantarum strainswere supplemented to fermented milk produced by commercial yogurt starters (Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus) and a panel of parameters reflecting product quality was subsequently monitored during 28 d of postfermentation storage. The pH value and titration acidity of the fermented milk mildly fluctuated, whereas the L. plantarum viable counts remained stable along the storage period. Fourteen key volatile compounds were detected in the fermented milk by gas chromatography-mass spectrometry, and some flavor compounds were uniquely present in the L. plantarum-supplemented fermented milk (including 2,3-pentanedione, acetaldehyde, and acetate). No significant difference was shown in the sensory evaluation scores between samples with or without L. plantarum supplementation, but a gradual decrease was observed over storage in all samples. However, when L. plantarum was added, apparent shifts were observed in the overall quality of the fermented milk based on principal component analysis and multivariate ANOVA, particularly in the texture (adhesiveness) and volatile flavor compound profiles (acetaldehyde). Compared with L. plantarum IMAU80106 and IMAU10216, both the texture and volatile flavor profiles of IMAU70095 were closest to those of the control without adding the adjunct bacteria, suggesting that IMAU70095 might be the most suitable strain for further application in functional dairy

Fermentative hydrogen production from cassava stillage by mixed anaerobic microflora: Effects of temperature and pH

Energy Technology Data Exchange (ETDEWEB)

Luo, Gang; Xie, Li; Zou, Zhonghai; Zhou, Qi [Key Laboratory of Yangtze River Water Environment, Ministry of Education (Tongji University), UNEP-Tongji, Tongji University, Siping Road No. 1239, Shanghai 200092 (China); Wang, Jing-Yuan (School of Civil and Environmental Engineering, Nanyang Technological University, N1-01b-45, 50 Nanyang Avenue, 639798 Singapore)

2010-12-15

Fermentative hydrogen production from cassava stillage was conducted to investigate the influences of temperature (37 C, 60 C, 70 C) and initial pH (4-10) in batch experiments. Although the seed sludge was mesophilic anaerobic sludge, maximum hydrogen yield (53.8 ml H{sub 2}/gVS) was obtained under thermophilic condition (60 C), 53.5% and 198% higher than the values under mesophilic (37 C) and extreme-thermophilic (70 C) conditions respectively. The difference was mainly due to the different VFA and ethanol distributions. Higher hydrogen production corresponded with higher ratios of butyrate/acetate and butyrate/propionate. Similar hydrogen yields of 66.3 and 67.8 ml H{sub 2}/gVS were obtained at initial pH 5 and 6 respectively under thermophilic condition. The total amount of VFA and ethanol increased from 3536 to 7899 mg/l with the increase of initial pH from 4 to 10. Initial pH 6 was considered as the optimal pH due to its 19% higher total VFA and ethanol concentration than that of pH 5. Homoacetogenesis and methonogenesis were very dependent on the initial pH and temperature even when the inoculum was heat-pretreated. Moreover, a difference between measured and theoretical hydrogen was observed in this study, which could be attributed to homoacetogenesis, methanogenesis and the degradation of protein. (author)

Influence of spontaneous fermentation on some quality ...

African Journals Online (AJOL)

Sensory evaluation indicated that the techniques of nixtamalization, fermentation and cowpea fortification used for the processing of the products did not influence their acceptability by the panel. Nixtamalized maize can therefore be subjected to spontaneous fermentation with cowpea fortification to enhance the functional, ...

Influence of fermentation temperature on the content of fatty acids in low energy milk-based kombucha products

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Malbaša Radomir V.

2011-01-01

Full Text Available The aim of this study was to investigate the influence of fermentation temperature on the fatty acids content in low energy milk-based products obtained by kombucha inoculums with herbal teas. In this investigation low energy milk-based kombucha products were produced from milk with 0.8% milk fat using 10% (v/v kombucha inoculums cultivated on winter savory, peppermint, stinging nettle and wild thyme. The process of fermentation was conducted at two temperatures: 40°C and 43°C. Fermentation was stopped after the pH value of 4.5 was reached. Duration of the fermentation process was shorter by applying higher fermentation temperature. Fatty acids content was determined by gas chromatography-mass spectrometry. Predominant fatty acids in all obtained products were saturated fatty acids, first of all the monounsaturated ones. The higher temperature resulted in the formation of lower amount of saturated fatty acids in the obtained milk-based kombucha products.

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

Science.gov (United States)

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

2004-04-07

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

Physico-chemical and microbiological properties of raw fermented sausages are not influenced by color differences of turkey breast meat.

Science.gov (United States)

Popp, J; Krischek, C; Janisch, S; Wicke, M; Klein, G

2013-05-01

It has been suggested that the color of turkey breast meat influences both physico-chemical and microbiological properties of raw fermented sausages. In this study, raw fermented sausages were produced with turkey breast meat in 3 different colors (pale, normal, or dark), which were obtained from 2 fast-growing-genetic-line toms at 2 slaughterhouses. Prior to the sausage production, the breast muscles were sorted into color groups according to the lightness values determined at 24 h postmortem. This meat was subsequently processed to raw fermented sausages using 1.5 or 2.5% curing salt (CS). The pale meat had higher lightness, electrical conductivity, and drip loss, whereas the dark meat showed a darker color only. The physico-chemical (pH, water activity), visual (lightness, redness), and microbial (total plate count) properties of the sausages were not influenced by the color of the turkey breast meat. The sausage made with 2.5% CS had lower aw and higher ash and hardness values than the sausages produced with 1.5% CS. In conclusion, processing of differently colored turkey meat to raw fermented sausages does not influence the quality characteristics of the products. Based on these findings, there is no reason for the sausage producer to separate turkey breast muscles by color before producing raw fermented sausages.

1 INFLUENCE OF SPONTANEOUS FERMENTATION ON SOME ...

African Journals Online (AJOL)

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... of Ghana,. P. O. Box LG 134, Legon-Accra, Ghana ... and sensory qualities of maize based foods thereby improving the qualities as well as .... Fig. 1. Effect of fermentation on the pH of maize-based cowpea-fortified ..... 1991; 7: 203-210. 4. ... International Workshop on Food-based Approaches for Healthy Nutrition in.

Influence of sodium chloride on wine yeast fermentation performance

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Stilianos Logothetis

2010-06-01

Full Text Available Stilianos Logothetis1, Elias T Nerantzis2, Anna Gioulioti3, Tasos Kanelis2, Tataridis Panagiotis2, Graeme Walker11University of Abertay Dundee, School of Contemporary Sciences, Dundee, Scotland; 2TEI of Athens Department of Oenology and Spirit Technology, Biotechnology and Industrial Fermentations Lab Agiou Spiridonos, Athens, Greece; 3Ampeloiniki SA Industrial Park Thermi, Thessaloniki, GreeceAbstract: This paper concerns research into the influence of salt (sodium chloride on growth, viability and fermentation performance in a winemaking strain of the yeast, Saccharomyces cerevisiae. Experimental fermentations were conducted in both laboratory-scale and industrial-scale experiments. Preculturing yeasts in elevated levels of sodium chloride, or salt “preconditioning” led to improved fermentation performance. This was manifest by preconditioned yeasts having an improved capability to ferment high-sugar containing media with increased cell viability and with elevated levels of produced ethanol. Salt-preconditioning most likely influenced the stress-tolerance of yeasts by inducing the synthesis of key metabolites such as trehalose and glycerol. These compounds may act to improve cells’ ability to withstand osmostress and ethanol toxicity during fermentations of grape must. Industrial-scale trials using salt-preconditioned yeasts verified the benefit of this novel physiological cell engineering approach to practical winemaking fermentations.Keywords: salt, preconditioning, fermentation performance, Saccharomyces cerevisiae, wine

Low energy Kombucha fermented milk-based beverages

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Milanović Spasenija D.

2008-01-01

Full Text Available This paper investigates manufacturing of fermented beverages from two types of milk (1 % w/w and 2.2 % w/w fat by applying of Kombucha, which contains several yeasts and bacterial strains. The starter was the inoculum produced from previous Kombucha fermentation. The applied starter concentrations were: 10 % v/v, 15 % v/v and 20 % v/v. Also, the traditional yoghurt starter was used to produce the control samples. All fermentations were performed at 42oC and the changes in the pH were monitored. The fermentation process was about three times faster in the control yoghurt than in the Kombucha samples. Influence of Kombucha inoculum concentration on the rate of fermentation appeared not to be significant. All fermentations were stopped when the pH reached 4.4. After the production, the quality of the fermented milk beverages with Kombucha was determined and compared with the quality of the control yoghurt samples. It was concluded that the difference in fat contents in milks affects the difference in quantities of other components in the fermented milk beverages with Kombucha. Sensory characteristics of the beverages manufactured from the partially skimmed milk are much better than those of the fermented beverages produced from the low fat milk.

The Effect of Rice Fermented (Tape Ketan Hitam Liquid Fraction Concentrations and Incubation Times on pH, Viscosity and Organoleptic Quality of Goat Milk

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Naili Iqrimah

2013-09-01

Full Text Available This study aimed to determine of interaction and the best of percentage rice fermented liquid fraction addition and incubation times on pH, viscosity and organoleptic quality. The experimental method was designed by factorial Completely Randomized Design (CRD which three times replicated. The treatment consists of rice fermented liquid fraction concentrations by 5 %, 15 %, 25 % and 35 % (v/v  and incubation times by 0 (without incubation , 8,16 and 24 hours. The results showed that the different concentration of rice fermented liquid fraction showed a significantly different effect on pH, viscosity, colour, smell, taste and textur, while  in incubation times gave a significantly different effect on pH, viscosity, smell, taste and textur but not give a significant effect on colour. The best combination obtained from addition of rice fermented liquid fraction 25 % and 24 hours of incubation times. Key words: goat milk, rice fermented liquid fraction, incubation times

Influence of pre-fermentation cold maceration treatment on aroma compounds of Cabernet Sauvignon wines fermented in different industrial scale fermenters.

Science.gov (United States)

Cai, Jian; Zhu, Bao-Qing; Wang, Yun-He; Lu, Lin; Lan, Yi-Bin; Reeves, Malcolm J; Duan, Chang-Qing

2014-07-01

The influence of pre-fermentation cold maceration (CM) on Cabernet Sauvignon wines fermented in two different industrial-scale fermenters was studied. CM treatment had different effects on wine aroma depending on the types of fermenter, being more effective for automatic pumping-over tank (PO-tank) than automatic punching-down tank (PD-tank). When PO-tank was used, CM-treated wine showed a decrease in some fusel alcohols (isobutanol and isopentanol) and an increase in some esters (especially acetate esters). However, no significant changes were detected in these compounds when PD-tank was used. Ethyl 2-hexenoate and diethyl succinate were decreased, while geranylacetone was increased by the CM treatment in both fermenters. β-Damascenone was increased by the CM treatment in PO-tank fermented wines but decreased in PD-tank fermented wines. The fruity, caramel and floral aroma series were enhanced while chemical series were decreased by the CM treatment in PO-tank fermented wines. The content of (Z)-6-nonen-1-ol in the final wines was positively correlated to CM treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Controlling composition and color characteristics of Monascus pigments by pH and nitrogen sources in submerged fermentation.

Science.gov (United States)

Shi, Kan; Song, Da; Chen, Gong; Pistolozzi, Marco; Wu, Zhenqiang; Quan, Lei

2015-08-01

Submerged fermentations of Monascus anka were performed with different nitrogen sources at different pH in 3 L bioreactors. The results revealed that the Monascus pigments dominated by different color components (yellow pigments, orange pigments or red pigments) could be selectively produced through pH control and nitrogen source selection. A large amount of intracellular pigments dominated by orange pigments and a small amount of water-soluble extracellular yellow pigments were produced at low pH (pH 2.5 and 4.0), independently of the nitrogen source employed. At higher pH (pH 6.5), the role of the nitrogen source became more significant. In particular, when ammonium sulfate was used as nitrogen source, the intracellular pigments were dominated by red pigments with a small amount of yellow pigments. Conversely, when peptone was used, intracellular pigments were dominated by yellow pigments with a few red pigments derivatives. Neither the presence of peptone nor ammonium sulfate promoted the production of intracellular orange pigments while extracellular pigments with an orangish red color were observed in both cases, with a higher yield when peptone was used. Two-stage pH control fermentation was then performed to improve desirable pigments yield and further investigate the effect of pH and nitrogen sources on pigments composition. These results provide a useful strategy to produce Monascus pigments with different composition and different color characteristics. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

PHYSIOLOGICAL REGULATION OF PROTEASE AND ANTIBIOTICS IN PENICILLIUM SP. USING SUBMERGED AND SOLID STATE FERMENTATION TECHNIQUES

OpenAIRE

HAIDER M. HAMZAH; ANWAR H.L. Ali; HAMID G. HASSAN

2009-01-01

A fungal strain belonging to the genus Penicillium was isolated from soil sample and has been diagnosed as Penicillium sp. according to its morphological characteristics of the colonies on solid media and also microscopical examination of the fungal parts. Antibiotics, protease activity and pH values were determined after cultivation of the fungus using submerged fermentation (SF) and solid state fermentation (SSF). The two different patterns of fermentation processes seem to influence the ph...

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

Science.gov (United States)

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.

Improved ethanol fermentation of a yeast mutant by C-12 ion beam irradiation

International Nuclear Information System (INIS)

Lu Dong; Liu Qingfang; Wu Xin; Wang Ying; Wang Jufang; Ma Shuang; Li Wenjian

2010-01-01

The yeast Saccharomyces cerevisiae YY was irradiated with 100 MeV/u 12 C 6+ ion beams. After screening,we obtained the mutant strain C03A of high ethanol yield. The influence of fermentation temperature, pH and concentration of sugar on ethanol fermentation were studied. The range analysis and analysis of variance were applied for the result of orthogonal experiments. The optimal ethanol fermentation conditions are: fermentation temperature 35 degree C, pH value 5.0, and sugar concentration 24%. The results of fermentation in the 10 L bioreactor showed that the ethanol fermentation of the mutant strain could be completed in 36 hours, the production of ethanol was to 13.2%(V/V), which means 12 hours faster and 1.6%(V /V) ethanol yield higher than original strain. (authors)

Mannitol production by heterofermentative Lactobacillus reuteri CRL 1101 and Lactobacillus fermentum CRL 573 in free and controlled pH batch fermentations.

Science.gov (United States)

Rodríguez, Cecilia; Rimaux, Tom; Fornaguera, María José; Vrancken, Gino; de Valdez, Graciela Font; De Vuyst, Luc; Mozzi, Fernanda

2012-03-01

Certain lactic acid bacteria, especially heterofermentative strains, are capable to produce mannitol under adequate culture conditions. In this study, mannitol production by Lactobacillus reuteri CRL 1101 and Lactobacillus fermentum CRL 573 in modified MRS medium containing a mixture of fructose and glucose in a 6.5:1.0 ratio was investigated during batch fermentations with free pH and constant pH 6.0 and 5.0. Mannitol production and yields were higher under constant pH conditions compared with fermentations with free pH, the increase being more pronounced in the case of the L. fermentum strain. Maximum mannitol production and yields from fructose for L. reuteri CRL 1101 (122 mM and 75.7 mol%, respectively) and L. fermentum CRL 573 (312 mM and 93.5 mol%, respectively) were found at pH 5.0. Interestingly, depending on the pH conditions, fructose was used only as an alternative external electron acceptor or as both electron acceptor and energy source in the case of the L. reuteri strain. In contrast, L. fermentum CRL 573 used fructose both as electron acceptor and carbon source simultaneously, independently of the pH value, which strongly affected mannitol production by this strain. Studies on the metabolism of these relevant mannitol-producing lactobacilli provide important knowledge to either produce mannitol to be used as food additive or to produce it in situ during fermented food production.

Factors influencing cassava - pulp fermentation period for gari ...

African Journals Online (AJOL)

Factors influencing cassava - pulp fermentation period for gari processing among ... Result of probit model analysis at 5% significance level shows an R value ... Marital status (2.236**) and respondents' cultural influences (1.960**) were ...

Biogas properties and enzymatic analysis during anaerobic fermentation of Phragmites australis straw and cow dung: influence of nickel chloride supplement.

Science.gov (United States)

Tian, Yonglan; Zhang, Huayong; Chai, Yang; Wang, Lijun; Mi, Xueyue; Zhang, Luyi; Ware, Maxwell Adam

2017-02-01

The importance of nickel (added as NiCl 2 ) on mesophilic anaerobic fermentation of Phragmites australis straw and cow dung was demonstrated by investigating the biogas properties, pH values, organic matter degradation [chemical oxygen demand (COD)] and enzyme activities (cellulase, protease and dehydrogenase) during the fermentation process. The results showed that Ni 2+ addition increased the cumulative biogas yields by >18 % by improving the efficiency of first peak stage and bringing forward the second peak stage. The pH values were not significantly influenced by Ni 2+ addition (p > 0.05). Biogas yields were associated with variations in COD concentrations rather than momentary concentrations. At the start-up stage of fermentation (4th day), the biogas yields increased gradually together with the increase of dehydrogenase activities at elevated Ni 2+ concentrations when cellulase and protease activities were similar in all test groups. It is suggested that Ni 2+ addition was mainly dependent on the methanogenic stage. After the start-up stage, the impact of Ni 2+ addition on biogas production was mainly dependent on its effect on cellulase activities, rather than protease or dehydrogenase activities.

Application of bipolar electrodialysis to E.coli fermentation for simultaneous acetate removal and pH control

DEFF Research Database (Denmark)

Wong, M.; Woodley, John; Lye, G.J.

2010-01-01

The application of bipolar electrodialysis (BPED) for the simultaneous removal of inhibitory acetate and pH control during E. coli fermentation was investigated. A two cell pair electrodialysis module, consisting of cation exchange, anion exchange and bipolar membranes with working area of 100 cm2...

Ultrafiltration of hemicellulose hydrolysate fermentation broth

Science.gov (United States)

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

2017-03-01

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

Industrial optimization of acetone-butanol fermentation: A study of the utilization of Jerusalem artichokes

Energy Technology Data Exchange (ETDEWEB)

Marchal, R.; Blanchet, D.; Vandecasteele, J.P.

1985-12-01

Acetone-butanol fermentation of the Jerusalem artichoke has been studied as a case for systematic investigation of the industrial optimization of both strain selection and fermentation operation. Hydrolysis of the inulinic oligofructans of the substrate was found necessary for optimal performance but could be achieved with a selected strain using a moderate amount of inulinase added at the beginning of the fermentation. Apart from ammonia, no nutritrional supplementation of the medium was found necessary. The marked influence of pH in the fermentation performance prompted a detailed search for a method of controlling pH during fermentation. With an optimized procedure, solvent production of 23-24 g/l were obtained in 36 h. Detailed fermentation balances are presented. An industrial process for ABE production from Jerusalem artichoke or sugar beet has been defined and tested in the pilot plant. (orig.).

Processed dairy beverages pH evaluation: consequences of temperature variation.

Science.gov (United States)

Ferreira, Fabiana Vargas; Pozzobon, Roselaine Terezinha

2009-01-01

This study assessed the pH from processed dairy beverages as well as eventual consequences deriving from different ingestion temperatures. 50 adults who accompanied children attended to at the Dentistry School were randomly selected and they answered a questionnaire on beverages. The beverages were divided into 4 groups: yogurt (GI) fermented milk (GII), chocolate-based products (GIII) and fermented dairy beverages (GIV). They were asked which type, flavor and temperature. The most popular beverages were selected, and these made up the sample. A pH meter Quimis 400A device was used to verify pH. The average pH from each beverage was calculated and submitted to statistical analysis (Variance and Tukey test with a 5% significance level). for groups I, II and III beverages, type x temperature interaction was significant, showing the pH averages were influenced by temperature variation. At iced temperatures, they presented lower pH values, which were considered statistically significant when compared to the values found for the same beverages at room temperature. All dairy beverages, with the exception of the chocolate-based type presented pH below critical level for enamel and present corrosive potential; as to ingestion temperature, iced temperature influenced pH reducing its values, in vitro.

Optimisation of minimal media for production of aroma compounds typical for fermented milk products

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Nevenka Mazić

2008-08-01

Full Text Available The aim of this research was to optimize the composition of minimalgrowth media containing lactose and milk, in which lactic acid bacteria (LAB would produce the maximum amount of volatile aroma compounds typical for fermented milk products. Ingredients used for the preparation of media were casein, tri-sodium-citrate, lactose, milk minerals, whey proteins and milk with 1.5% fat. The several prepared media differed mainly in the amount of citrate and whey proteins. Fermentation was carried out at room temperature until the media reached pH value of 5. Samples were evaluated for sensory characteristics using quantitative descriptive analysis (QDA. In all media the target pH was reached after 68-71 hours of fermentation, depending on citrate level. Fermentation and the production of aroma compounds were more intensive in media that contained whey proteins compared to media with only casein. Increased citrate level had a positive influence on the aroma production. Citrate increased the initial pH of the media and acted as a buffer during fermentation, which lead to longer fermentation and prolonged production of aroma compounds. At pH around 5, the desired cultured aroma was the most intensive, whereas sour taste was less dominant. The substrate with 0.25% citrate and 0.1% whey proteins, at pH 5, was rated as best regarding its sensory characteristics.

Effects of inulin chain length on fermentation by equine fecal bacteria and Streptococcus bovis

Science.gov (United States)

Fructans from pasture can be fermented by Gram-positive bacteria (e.g., Streptococcus bovis) in the equine hindgut, increasing production of lactic acid and decreasing pH. The degree of polymerization (DP) of fructans has been suggested to influence fermentation rates. The objective of the current ...

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.

Effect of submerged and solid-state fermentation on pigment and citrinin production by Monascus purpureus.

Science.gov (United States)

Zhang, Liang; Li, Zhiqiang; Dai, Bing; Zhang, Wenxue; Yuan, Yongjun

2013-09-01

Monascus pigments, which are produced by various species of Monascus, often have been used as a natural colourant and as traditional natural food additives, especially in Southern China, Japan and Southeastern Asia. The limitation of wide using Monascus pigment is attributed to one of its secondary metabolites named citrinin. The aim of this study was to investigate the influence of pigment and citrinin production via submerged fermentation (SmF) and solid-state fermentation (SF) from rice (Oryza sativa L.) by Monascus purpureus AS3.531. The optimal fermentation temperature and pH were significantly different for pigment production through different fermentation mode (35 °C, pH 5.0 for SF and 32 °C, pH 5.5 for SmF, respectively). Adding 2% (w/v) of glycerol in the medium could enhance the pigment production. On the optimized condition, although the concentration of citrinin produced by SmF (19.02 ug/g) increased more than 100 times than that by SF (0.018 ug/g), the pigment yield by SmF (7.93 U/g/g) could be comparable to that by SF (6.63 U/g/g). Those indicate us that fermentation mode seems to be the primary factor which influence the citrinin yield and secondary factor for pigment production.

Electrolytic extraction drives volatile fatty acid chain elongation through lactic acid and replaces chemical pH control in thin stillage fermentation.

Science.gov (United States)

Andersen, Stephen J; Candry, Pieter; Basadre, Thais; Khor, Way Cern; Roume, Hugo; Hernandez-Sanabria, Emma; Coma, Marta; Rabaey, Korneel

2015-01-01

Volatile fatty acids (VFA) are building blocks for the chemical industry. Sustainable, biological production is constrained by production and recovery costs, including the need for intensive pH correction. Membrane electrolysis has been developed as an in situ extraction technology tailored to the direct recovery of VFA from fermentation while stabilizing acidogenesis without caustic addition. A current applied across an anion exchange membrane reduces the fermentation broth (catholyte, water reduction: H2O + e(-) → ½ H2 + OH(-)) and drives carboxylate ions into a clean, concentrated VFA stream (anolyte, water oxidation: H2O → 2e(-) + 2 H(+) + O2). In this study, we fermented thin stillage to generate a mixed VFA extract without chemical pH control. Membrane electrolysis (0.1 A, 3.22 ± 0.60 V) extracted 28 ± 6 % of carboxylates generated per day (on a carbon basis) and completely replaced caustic control of pH, with no impact on the total carboxylate production amount or rate. Hydrogen generated from the applied current shifted the fermentation outcome from predominantly C2 and C3 VFA (64 ± 3 % of the total VFA present in the control) to majority of C4 to C6 (70 ± 12 % in the experiment), with identical proportions in the VFA acid extract. A strain related to Megasphaera elsdenii (maximum abundance of 57 %), a bacteria capable of producing mid-chain VFA at a high rate, was enriched by the applied current, alongside a stable community of Lactobacillus spp. (10 %), enabling chain elongation of VFA through lactic acid. A conversion of 30 ± 5 % VFA produced per sCOD fed (60 ± 10 % of the reactive fraction) was achieved, with a 50 ± 6 % reduction in suspended solids likely by electro-coagulation. VFA can be extracted directly from a fermentation broth by membrane electrolysis. The electrolytic water reduction products are utilized in the fermentation: OH(-) is used for pH control without added chemicals, and H2 is

Effect of fermentation and sterilization on anthocyanins in blueberry.

Science.gov (United States)

Nie, Qixing; Feng, Lei; Hu, Jielun; Wang, Sunan; Chen, Haihong; Huang, Xiaojun; Nie, Shaoping; Xiong, Tao; Xie, Mingyong

2017-03-01

Blueberry products have various health benefits due to their high content of dietary anthocyanins. The aim of this study was to investigate the impact of fermentation and sterilization on total anthocyanin content, composition and some quality attributes of blueberry puree. The blueberry puree used here was fermented for 40 h at 37 °C by Lactobacillus after sterilization. The method of ultra-performance liquid chromatography-mass spectrometry was optimized for the rapid analysis of anthocyanins. Quality attributes including pH, color, total soluble solids and viscosity were measured. A total of 21 anthocyanins and five anthocyanidins were quantified by ultra-performance liquid chromatography. Fermented blueberry had reduced total anthocyanin content (29%) and levels of individual anthocyanins compared with fresh blueberry. Total anthocyanin content was decreased 46% by sterilization, and different degradation behavior of individual anthocyanin was appeared between fermented and sterilized-fermented blueberry puree. Fermentation and sterilization decreased the total soluble solids and pH and changed color parameters, while minimally influencing viscosity. The loss of total anthocyanin content by fermentation was related to the unstable structure of blueberry anthocyanins. Anthocyanins are sensitive to temperature (>80 °C), and degradation of anthocyanins by sterilization in blueberry should be considered in the fermentation procedure. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Influence of pH on the physicochemical and sensorial characteristics of strawberry frozen yogurtInfluência do pH nas características físico-químicas e sensoriais de frozen yogurt de morango

Directory of Open Access Journals (Sweden)

Jaime Vilela de Resende

2012-05-01

Full Text Available Frozen yogurt is a frozen fermented dessert which presents structural characteristics similar to ice cream and nutritional and sensorial properties which resemble to yogurt. The acidification of ice cream mix by means of lactic bacteria can influence the properties of frozen yogurt. For that reason, the present work aimed to evaluate the influence of pH on the physicochemical and sensorial characteristics of strawberry frozen yogurt. The formulation consisted of 6 % of milk fat, 10 % of milk solids-not-fat, 11 % of sucrose, 3 % of corn syrup, 0.3 % of emulsifiers and 0.5 % of stabilizers. The frozen yogurt mixes were made with different fermentation endpoints, pH values of 4.5, 5.0 and 5.5. The strawberry fruit mixture was added to the fermented frozen yogurt mix at a level of 4 % (w/w. According to the results, the pH of the frozen yogurt mix did not influence the concentrations of protein, fat and ash whereas the contents of acidity, reducing, non-reducing and total sugars underwent influence of pH due to fermentation. The acceptability of frozen yogurt in relation to the attributes flavor, texture, overall acceptance and ideal acidity was evaluated. It was found that pH influenced the acceptance of frozen yogurt; the treatments with final pH of 5.0 and 5.5 presented higher acceptability for all the treatments evaluated and acidity close to the ideal. By means of the principal component analysis, it was found that the physicochemical characteristics acidity content and sugar concentration (reducing, non-reducing and total had effect on the acceptance of the product. In conclusion, the strawberry frozen yogurts with pH 5.0 and 5.5 demonstrated good sensorial acceptance and thus, presented potential of being better explored by the ice cream industries. O frozen yogurt é uma sobremesa fermentada congelada que apresenta características estruturais semelhantes ao sorvete e propriedades nutricionais e sensoriais que se assemelham ao iogurte. A

Biohydrogen production from household solid waste (HSW) at extreme-thermophilic temperature (70 degrees C) - Influence of pH and acetate concentration

DEFF Research Database (Denmark)

Liu, Dawei; Min, Booki; Angelidaki, Irini

2008-01-01

Hydrogen production from household solid waste (HSW) was performed via dark fermentation by using an extreme-thermophilic mixed culture, and the effect of pH and acetate on the biohydrogen production was investigated. The highest hydrogen production yield was 257 +/- 25 mL/gVS(added) at the optimum...... pH of 7.0. Acetate was proved to be inhibiting the dark fermentation process at neutral pH, which indicates that the inhibition was caused by total acetate concentration not by undissociated acetate. Initial inhibition was detected at acetate concentration of 50 mM, while the hydrogen fermentation...

Influence of activated carbon amended ASBR on anaerobic fermentative hydrogen production

DEFF Research Database (Denmark)

Xie, Li; Wang, Lei; Zhou, Qi

2013-01-01

The effect of activated carbon amended ASBR on fermentative bio-hydgrogen production from glucose was evaluated at hydraulic retention time (HRTs) ranging from 48 h to 12 h with initial pH of 6.0 at the system temperature of 60°C. Experimental results showed that the performance of activated carbon...... amended anazrobic seguencs batch reactor (ASBRs) was more stable than that of ASBRs without activated carbon addition regarding on hydrogen production and pH. Higher hydrogen yield(HY) and hydrogen producing rate(HPR) were observed in the activated carbon amended ASBRs, with 65%, 63%, 54%, 56% enhancement...... of hydrogen yield in smaller size activated carbon amended reactor under the tested HRT ranges, and the maximum HPR of (7.09±0.31)L·(L·d)-1 and HY of (1.42±0.03) mol·mol-1 was obtained at HRT of 12h. The major soluble products form hydrogen fermentation were n-butyric acid and acetic acid, accounting for 46...

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.

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

Science.gov (United States)

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

2018-02-14

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

Bacterial community dynamics and product distribution during pH-adjusted fermentation of vegetable wastes.

Science.gov (United States)

Ye, N-F; Lü, F; Shao, L-M; Godon, J-J; He, P-J

2007-10-01

To estimate the effect of pH on the structures of bacterial community during fermentation of vegetable wastes and to investigate the relationship between bacterial community dynamics and product distribution. The bacterial communities in five batch tests controlled at different pH values [uncontrolled (about pH 4), 5, 6, 7 and 8] were monitored by denaturing gradient gel electrophoresis (DGGE) and single-strand conformation polymorphism (SSCP). The two fingerprinting methods provided consistent results and principal component analysis indicated a close similarity of bacterial community at pH 7 and 8 in addition to those at pH 4-6. This clustering also corresponded to dominant metabolic pathway. Thus, pH 7-8 shifted from alcohol-forming to acid-forming, especially butyric acid, whereas both alcohol-forming and acid-forming dominated at pH 5-6, and at pH 4, fermentation was inhibited. Shannon-weaver index was calculated to analyse the DGGE profiles, which revealed that the bacterial diversities at pH 7 and 8 were the highest while those at pH 5 and 4 (uncontrolled) were the lowest. According to sequencing results of the bands excised from DGGE gels, lactic acid bacteria and Clostridium sp. were predominant at all pH values, but varieties in species were observed as pH changed and time prolonged. The bacterial community during fermentation was materially influenced by pH and the diverse product distribution was related to the shift of different bacterial population. The study reveals that the impact of pH on fermentation product distribution is implemented primarily by changes of bacterial community. It also provides information about the comparison of two fingerprinting methods, DGGE and SSCP.

Fermentation temperature and wort composition influence on diacetyl and 2, 3-pentanedione contents in beer

Directory of Open Access Journals (Sweden)

Pejin Jelena D.

2005-01-01

Full Text Available Diacetyl and 2,3-pentanedione are important constituents of beer sensory properties. A new GC/MS method for diacetyl and 2,3-pentanedione content determination was developed. This method was applied for the determination of diacetyl and 2,3-pentanedione contents during beer fermentation (primary fermentation and maturation. Primary fermentations were carried out at different temperatures (8°C and 14°C. Primary fermentation temperature had a great influence on diacetyl and 2,3-pentanedione formation and reduction. Formation and reduction rates increased with the primary fermentation temperature increasment. Diacetyl and 2,3-pentanedione contents also increased with the corn grits increasment. Fermentations were carried out with Saccharomyces cerevisiae pure culture, specially prepared for each fermentation. This GC/MS method for diacetyl and 2,3-pentanedione determination was valuable for analysing the influence of wort composition or fermentation conditions such as primary fermentation temperature on their formation and reduction.

The possibility of lactic acid fermentation in the triticale stillage

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MILICA MARKOVIĆ

2011-06-01

Full Text Available Triticale stillage is a by-product of bioethanol production. A research study was conducted in order to see if triticale stillage is adequate for lactic acid bacteria growth and lactic acid fermentation. Three Lactobacillus strains: Lactobacillus fermentum NRRL-B-75624, Lactobacillus fermentum PL-1, and Lactobacillus plantarum PL-4 were taken into consideration. Lactic acid fermentation was monitored by measuring pH value and titratable acidity. Lactobacillus fermentum PL-1 had the greatest decrease of pH values and increase of titratable acidity so it was chosen for future work. During the research, it was investigated how nutrient composition of triticale stillage and CaCO3 can influence lactic acid fermentation and CaCO3 role in cell protection. The nutrient composition of triticale stillage was satisfactory for lactic acid fermentation. The addition of CaCO3 helped in lactic acid fermentation. Although the titratable acidity in the samples with CaCO3 was lower than in the samples without CaCO3, the number of viable cells was higher for the samples with CaCO3, which showed that CaCO3 protected lactic acid cells from inhibition by lactic acid.

On the influence of thiamine and ammonium ions on alcoholic fermentation

NARCIS (Netherlands)

Maesen, Th.J.M.

1953-01-01

1. 1. In a glucose-sodium acetate medium of pH 5.6 the fermentation rate of bakers' yeast remains constant at a low level during several hours, while in the presence of ammonium sulphate it gradually increases. The rise is steeper in the presence of thiamine. 2. 2. After the ammonium ions have

EVALUATION OF FERMENTATION PARAMETERS DURING HIGH-GRAVITY BEER PRODUCTION

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R.B. Almeida

2001-12-01

Full Text Available A large number of advantages are obtained from the use of highly concentrated worts during the production of beer in a process referred to as "high-gravity". However, problems related to slow or stuck fermentations, which cause the lower productivity and possibility of contamination, are encountered. This study examines the influence of factors pH, percentage of corn syrup, initial wort concentration and fermentation temperature on the fermentation parameters, namely productivity, wort attenuation and the yield coefficient for sugar-to-ethanol conversion. The results show that productivity increased when the higher temperature, the higher wort concentration and the lower syrup percentage were used, while wort attenuation increased when lower wort concentration and no syrup were used. The yield coefficient for sugar-to-ethanol conversion was not influenced by any of the factors studied.

Enhanced Microbial, Functional and Sensory Properties of Herbal Yogurt Fermented with Korean Traditional Plant Extracts

OpenAIRE

Joung, Jae Yeon; Lee, Ji Young; Ha, Young Sik; Shin, Yong Kook; Kim, Younghoon; Kim, Sae Hun; Oh, Nam Su

2016-01-01

This study evaluated the effects of two Korean traditional plant extracts (Diospyros kaki THUNB. leaf; DK, and Nelumbo nucifera leaf; NN) on the fermentation, functional and sensory properties of herbal yogurts. Compared to control fermentation, all plant extracts increased acidification rate and reduced the time to complete fermentation (pH 4.5). Supplementation of plant extracts and storage time were found to influence the characteristics of the yogurts, contributing to increased viability ...

Physiological and fermentation properties of Bacillus coagulans and a mutant lacking fermentative lactate dehydrogenase activity.

Science.gov (United States)

Su, Yue; Rhee, Mun Su; Ingram, Lonnie O; Shanmugam, K T

2011-03-01

Bacillus coagulans, a sporogenic lactic acid bacterium, grows optimally at 50-55 °C and produces lactic acid as the primary fermentation product from both hexoses and pentoses. The amount of fungal cellulases required for simultaneous saccharification and fermentation (SSF) at 55 °C was previously reported to be three to four times lower than for SSF at the optimum growth temperature for Saccharomyces cerevisiae of 35 °C. An ethanologenic B. coagulans is expected to lower the cellulase loading and production cost of cellulosic ethanol due to SSF at 55 °C. As a first step towards developing B. coagulans as an ethanologenic microbial biocatalyst, activity of the primary fermentation enzyme L-lactate dehydrogenase was removed by mutation (strain Suy27). Strain Suy27 produced ethanol as the main fermentation product from glucose during growth at pH 7.0 (0.33 g ethanol per g glucose fermented). Pyruvate dehydrogenase (PDH) and alcohol dehydrogenase (ADH) acting in series contributed to about 55% of the ethanol produced by this mutant while pyruvate formate lyase and ADH were responsible for the remainder. Due to the absence of PDH activity in B. coagulans during fermentative growth at pH 5.0, the l-ldh mutant failed to grow anaerobically at pH 5.0. Strain Suy27-13, a derivative of the l-ldh mutant strain Suy27, that produced PDH activity during anaerobic growth at pH 5.0 grew at this pH and also produced ethanol as the fermentation product (0.39 g per g glucose). These results show that construction of an ethanologenic B. coagulans requires optimal expression of PDH activity in addition to the removal of the LDH activity to support growth and ethanol production.

The Influenced of Lactobacillus plantarum Starter Addition and The Length Time of Fermentation Process on The Activity of Seaweed Antioxidant Ulva lactuca from Krakal Beach, Yogyakarta

Science.gov (United States)

Ambarsari, N. D.; Rushanti, I. R. P. A.; Setyaji, A.; Ningsih, T. R.; Nurhana, N.; Subekhi, I.; Dewi, E. N.

2018-02-01

Seaweed contains phenol compound functioning as antioxidant. Lactobacillus plantarum starter addition in a fermentation process was expected will increase the activity of antioxidant. The purpose of this research was to determine the influence of L. plantarum addition and the length of fermentation on the activity of antioxidant in U. lactuca. The experiment was conducted with factorial design. The first treatment consisted 2 different factors namely without L. plantarum addition and L. plantarum addition. While the second treatment were the different length fermentation time: 0, 12, 24, and 36 hours. Each treatment were done in thriplicate. The data was analyzed using ANOVA and BNJ test was applied if there any differences betweenthe treatments. The results showed that the fresh U. lactuca with L. plantarum addition for 36 hours fermentation had TPC BAL 9,83 CFU/ml, pH 4,26, phenol 231 ppm and antioxidant activity IC501375,12 ppm. Dried U. lactuca with L. plantarum addition that was fermentized for 36 hours had TPC BAL 9,10 CFU/ml, pH 4,75, phenol 166,24 ppm and antioxidant activity IC504070,32 ppm. The fresh U. lactuca with L. plantarum addition for 36 hours fermentation was the best treatment since the antioxidant activity is IC501375,12 ppm. Although the antioxidant activity was categorized as weak but it was still showed an increase compared to the result of antioxidant activity with maceration method using n-hexana dissolver which was 11213,76 ppm, ethyl acetate 9770,285 ppm, and ethanol extact 4921,79 ppm.

pH and Organic Carbon Dose Rates Control Microbially Driven Bioremediation Efficacy in Alkaline Bauxite Residue.

Science.gov (United States)

Santini, Talitha C; Malcolm, Laura I; Tyson, Gene W; Warren, Lesley A

2016-10-18

Bioremediation of alkaline tailings, based on fermentative microbial metabolisms, is a novel strategy for achieving rapid pH neutralization and thus improving environmental outcomes associated with mining and refining activities. Laboratory-scale bioreactors containing bauxite residue (an alkaline, saline tailings material generated as a byproduct of alumina refining), to which a diverse microbial inoculum was added, were used in this study to identify key factors (pH, salinity, organic carbon supply) controlling the rates and extent of microbially driven pH neutralization (bioremediation) in alkaline tailings. Initial tailings pH and organic carbon dose rates both significantly affected bioremediation extent and efficiency with lower minimum pHs and higher extents of pH neutralization occurring under low initial pH or high organic carbon conditions. Rates of pH neutralization (up to 0.13 mM H + produced per day with pH decreasing from 9.5 to ≤6.5 in three days) were significantly higher in low initial pH treatments. Representatives of the Bacillaceae and Enterobacteriaceae, which contain many known facultative anaerobes and fermenters, were identified as key contributors to 2,3-butanediol and/or mixed acid fermentation as the major mechanism(s) of pH neutralization. Initial pH and salinity significantly influenced microbial community successional trajectories, and microbial community structure was significantly related to markers of fermentation activity. This study provides the first experimental demonstration of bioremediation in bauxite residue, identifying pH and organic carbon dose rates as key controls on bioremediation efficacy, and will enable future development of bioreactor technologies at full field scale.

Synergetic effect of pH and biochemical components on bacterial diversity during mesophilic anaerobic fermentation of biomass-origin waste.

Science.gov (United States)

Lü, F; Shao, L M; Bru, V; Godon, J J; He, P J

2009-02-01

To investigate the synergetic effect of pH and biochemical components on bacterial community structure during mesophilic anaerobic degradation of solid wastes with different origins, and under acidic or neutral conditions. The bacterial community in 16 samples of solid wastes with different biochemical compositions and origins was evaluated during mesophilic anaerobic degradation at acidic and neutral pH. Denaturing gradient gel electrophoresis (DGGE) and single-strand conformation polymorphism (SSCP) were used to compare the communities. Multivariate analysis of the DGGE and SSCP results revealed that most of the dominant microbes were dependent on the content of easily degradable carbohydrates in the samples. Furthermore, the dominant microbes were divided into two types, those that preferred an acid environment and those that preferred a neutral environment. A shift in pH was found to change their preference for medium substrates. Although most of the substrates with similar origin and biochemical composition had similar microbial diversity during fermentation, some microbes were found only in substrates with specific origins. For example, two microbes were only found in substrate that contained lignocellulose and animal protein without starch. These microbes were related to micro-organisms that are found in swine manure, as well as in other intestinal or oral niches. In addition, the distribution of fermentation products was less sensitive to the changes in pH and biochemical components than the microbial community. Bacterial diversity during anaerobic degradation of organic wastes was affected by both pH and biochemical components; however, pH exerted a greater effect. The results of this study reveal that control of pH may be an effective method to produce a stable bacterial community and relatively similar product distribution during anaerobic digestion of waste, regardless of variation in the waste feedstocks.

Influence of carbon source, pH, and temperature on the polygalacturonase activity of Kluyveromyces marxianus CCMB 322

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Rodrigo de Queiroz Oliveira

2012-09-01

Full Text Available Microbial pectinolytic enzymes are known to play a commercially important role in a number of industrial processes. Two kinds of yeast can be discerned regarding the production of enzymes. One group includes those which can produce enzymes in the absence of an inducer, and the other group comprises the yeasts that produce enzymes in the presence of an inducer. The objective of this study was to investigate the influence of pectic substances, glucose, pH, and temperature on the polygalacturonase activity by Kluyveromyces marxianus CCMB 322. The yeast was grown in a fermentation broth containing different concentrations of glucose and pectic substances. The polygalacturonase activity was determined by the DNS method, and the pH and temperature were optimized using a central composite experimental design. The polygalacturonase secreted by K. marxianus CCMB 322 was partially constitutive showing optimum pH and temperature of 7.36 and 70 °C, respectively, and maintained approximately 93% of its original activity for 50 minutes at 50 °C. Thermal stability of the polygalacturonase enzyme was studied at different temperatures (50, 60, 70, and 80 °C and different incubation times (0, 10, 20, 30, 40, and 50 minutes. This study showed that glucose can influence the regulation of the synthesis of polygalacturonase.

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.

A critical review on factors influencing fermentative hydrogen production.

Science.gov (United States)

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

2017-03-01

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

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).

Determination of buffering capacity of selected fermented feedstuffs and the effect of dietary acid-base status on ruminal fluid pH

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Lukáš Bujňák

2011-01-01

Full Text Available The aim of this study was to evaluate the buffering capacity of some fermented feedstuffs and the effect of dietary acid-base status on ruminal fluid pH. The first experiment was performed with different types (n = 24 of wet and dry fermented feedstuffs to determine the buffering capacity and buffer value index. The buffer value index of wet corn silages was more negative than for dry corn silages account on acid loss during drying. In the second experiment, the effects of different concentrations of lactic acid on base-buffering capacity, buffer value index and indicators of fermentation process were studied in two groups of corn silages (n = 21. Two groups of analyzed values were compared using unpaired t-test. Differences among the groups in base-buffering capacity (P P P > 0.05 correlation was found between ruminal pH and dietary buffer value index. These results confirmed that dietary acid-base status alone is not adequate as a predictor of the need for buffers in the diet of lactating cows. It is the first report about using of buffering capacity determination methods for evaluation of feedstuffs and dietary acid-base status in dairy cows.

Effect of Fermentation Conditions and Plucking Standards of Tea Leaves on the Chemical Components and Sensory Quality of Fermented Juice

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Ping Tang

2018-01-01

Full Text Available The effects of fermentation conditions (temperature, time, and pH and plucking standards (one leaf and a bud to four leaves and a bud on the chemical components and sensory quality of the fermented juices processed from crushed fresh tea leaves were investigated. The results showed that optimum fermentation conditions that resulted in fermented juices of the best sensory quality and the highest content of TFs were a temperature of 35°C, time duration of 75 min, and pH 5.1. The fermented juices processed from new shoots with three leaves and a bud or four leaves and a bud afforded high overall acceptability and TF concentration. These differences arise because tea leaves with different plucking standards have different catechin content and enzyme activities. Fermented tea juice possessed higher concentrations of chemical components such as soluble solids, amino acids, and TFs and exhibited better sensory quality as compared to black tea infusion. The TF concentrations decreased as the pH of the fermenting juice increased, and the fermented juice showed the best overall acceptability. These results provide essential information for the improvement of the processing of black tea beverage by suggesting fermentation of fresh tea leaves as a better alternative to their infusion.

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

Science.gov (United States)

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

2013-08-15

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

Fermentation and microflora of plaa-som, a Thai fermented fish product prepared with different salt concentrations

DEFF Research Database (Denmark)

Paludan-Müller, Christine; Madsen, M.; Sophanodora, P.

2002-01-01

% salt (w/w) as well as two high-salt batches, containing 9% and 11% salt. pH decreased rapidly from 6 to 4.5 in low-salt batches, whereas in high-salt batches, a slow or no decrease in pH was found. Lactic acid bacteria (LAB) and yeasts were isolated as the dominant microorganisms during fermentation....... LAB counts increased to 108-109 cfu g-1 and yeast counts to 107-5 x 107 cfu g-1 in all batches, except in the 11% salt batch, where counts were 1-2 log lower. Phenotypic tests, ITS-PCR, carbohydrate fermentations and 16S rRNA gene sequencing identified LAB isolates as Pediococcus pentosaceus......Plaa-som is a Thai fermented fish product prepared from snakehead fish, salt, palm syrup and sometimes roasted rice. We studied the effects of different salt concentrations on decrease in pH and on microflora composition during fermentation. Two low-salt batches were prepared, containing 6% and 7...

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.

Fermentative Bacteria Influence the Competition between Denitrifiers and DNRA Bacteria

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Eveline M. van den Berg

2017-09-01

Full Text Available Denitrification and dissimilatory reduction to ammonium (DNRA are competing nitrate-reduction processes that entail important biogeochemical consequences for nitrogen retention/removal in natural and man-made ecosystems. The nature of the available carbon source and electron donor have been suggested to play an important role on the outcome of this microbial competition. In this study, the influence of lactate as fermentable carbon source on the competition for nitrate was investigated for varying ratios of lactate and nitrate in the influent (Lac/N ratio. The study was conducted in an open chemostat culture, enriched from activated sludge, under strict anoxia. The mechanistic explanation of the conversions observed was based on integration of results from specific batch tests with biomass from the chemostat, molecular analysis of the biomass enriched, and a computational model. At high Lac/N ratio (2.97 mol/mol both fermentative and respiratory nitrate reduction to ammonium occurred, coupled to partial oxidation of lactate to acetate, and to acetate oxidation respectively. Remaining lactate was fermented to propionate and acetate. At a decreased Lac/N ratio (1.15 mol/mol, the molar percentage of nitrate reduced to ammonium decreased to 58%, even though lactate was supplied in adequate amounts for full ammonification and nitrate remained the growth limiting compound. Data evaluation at this Lac/N ratio suggested conversions were comparable to the higher Lac/N ratio, except for lactate oxidation to acetate that was coupled to denitrification instead of ammonification. Respiratory DNRA on acetate was likely catalyzed by two Geobacter species related to G. luticola and G. lovleyi. Two Clostridiales members were likely responsible for lactate fermentation and partial lactate fermentation to acetate coupled to fermentative DNRA. An organism related to Propionivibrio militaris was identified as the organism likely responsible for denitrification. The

Comparison of microbial fermentation of high- and low-forage diets in Rusitec, single-flow continuous-culture fermenters and sheep rumen.

Science.gov (United States)

Carro, M D; Ranilla, M J; Martín-García, A I; Molina-Alcaide, E

2009-04-01

Eight Rusitec and eight single-flow continuous-culture fermenters (SFCCF) were used to compare the ruminal fermentation of two diets composed of alfalfa hay and concentrate in proportions of 80 : 20 (F80) and 20 : 80 (F20). Results were validated with those obtained previously in sheep fed the same diets. Rusitec fermenters were fed once daily and SFCCF twice, but liquid dilution rates were similar in both types of fermenters. Mean values of pH over the 12 h postfeeding were higher (P 0.05) were found in any in vitro system. A more precise control of pH in both types of fermenters and a reduction of concentrate retention time in Rusitec could probably improve the simulation of in vivo fermentation.

Ethanol production from olive prunings by autohydrolysis and fermentation with Candida tropicalis

Energy Technology Data Exchange (ETDEWEB)

Garcia Martin, Juan Francisco; Bravo, Vicente [Department of Chemical Engineering, University of Granada, Campus Universitario de Fuentenueva, 18071 Granada (Spain); Cuevas, Manuel; Sanchez, Sebastian [Department of Chemical, Environmental and Materials Engineering, University of Jaen, Campus Las Lagunillas, 23071 Jaen (Spain)

2010-07-15

Hydrolysates from olive prunings (a renewable, low-cost, easily available, agricultural residue) were fermented with the unconventional yeast Candida tropicalis NBRC 0618 to produce not only ethanol fuel but also xylitol as a by-product, which adds value to the economic viability of the bioprocess. Autohydrolysis took place at 200 C in a stirred stainless-steel tank reactor. The influence of the solid/liquid ratio in the reactor was studied. Fermentation experiments were conducted in a batch-culture reactor at a temperature of 30 C, a stirring rate of 500 rpm and pH values of between 5.0 and 6.5. Under the operating conditions tested the highest yields of ethanol and xylitol were obtained with the hydrolysate fermented at pH 5.0 and solely the airflow that entered via the stirring vortex. Under these conditions, the instantaneous ethanol yield was 0.44 g g{sup -1} and the overall xylitol yield 0.13 g g{sup -1}. (author)

Influence of red wine fermentation oenological additives on inoculated strain implantation.

Science.gov (United States)

Duarte, Filomena L; Alves, Ana Claudia; Alemão, Maria Filomena; Baleiras-Couto, M Margarida

2013-06-01

Pure selected cultures of Saccharomyces cerevisiae starters are regularly used in the wine industry. A survey of S. cerevisiae populations during red wine fermentations was performed in order to evaluate the influence of oenological additives on the implantation of the inoculated strain. Pilot scale fermentations (500 L) were conducted with active dry yeast (ADY) and other commercial oenological additives, namely two commercial fermentation activators and two commercial tannins. Six microsatellite markers were used to type S. cerevisiae strains. The methodology proved to be very discriminating as a great diversity of wild strains (48 genotypes) was detected. Statistical analysis confirmed a high detection of the inoculated commercial strain, and for half the samples an effective implantation of ADY (over 80 %) was achieved. At late fermentation time, ADY strain implantation in fermentations conducted with commercial additives was lower than in the control. These results question the efficacy of ADY addition in the presence of other additives, indicating that further studies are needed to improve knowledge on oenological additives' use.

Effects of pH value and substrate concentration on hydrogen production from the anaerobic fermentation of glucose

Energy Technology Data Exchange (ETDEWEB)

Li, Zhi; Wang, Hui; Tang, Zongxun; Wang, Xiaofang [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), Department of Chemisty, Northwest University, Xi' an 710069 (China); Bai, Jinbo [Lab. MSS/MAT, CNRS UMR 8579, Ecole Centrale Paris, 92295 Chatenay Malabry (France)

2008-12-15

A series of batch experiments were conducted to investigate the effects of pH and glucose concentrations on biological hydrogen production by using the natural sludge obtained from the bed of a local river as inoculant. Batch experiments numbered series I and II were designed at an initial and constant pH of 5.0-7.0 with 1.0 increment and four different glucose concentrations (5.0, 7.5, 10 and 20 g glucose/L). The results showed that the optimal condition for anaerobic fermentative hydrogen production is 7.5 g glucose/L and constant pH 6.0 with a maximum H{sub 2} production rate of 0.22 mol H{sub 2} mol{sup -1} glucose h{sup -1}, a cumulative H{sub 2} yield of 1.83 mol H{sub 2} mol{sup -1} glucose and a H{sub 2} percentage of 63 in biogas. (author)

Bio-hydrogen production from hyacinth by anaerobic fermentation

International Nuclear Information System (INIS)

Cheng Jun; Zhou Junhu; Qi Feng; Xie Binfei; Cen Kefa

2006-01-01

The bio-hydrogen production from hyacinth by anaerobic fermentation of digested sludge is studied in this paper. The compositions of bio-gases and volatile fatty acids in fermentation liquids are determined on TRACE 2000 gas chromatography. It is found that the H 2 concentration in the biogas is 10%-20% and no CH 4 is detected. The bio-hydrogen production from hyacinth with the initial pH value of 5.5 is higher than that with the initial pH value of 4.5. The fermentation temperature of 55 C is better than that of 35 C, while the weight ratio of hyacinth to microorganism of 1:1 is better than that of 3:7. The highest hydrogen production of 122.3 mL/g is obtained when the initial pH value of fermentation solution is 5.5, the fermentation temperature is 55 C and the weight ratio of hyacinth to microorganism is 1:1. (authors)

Comparison of fermentation of diets of variable composition and microbial populations in the rumen of sheep and Rusitec fermenters. I. Digestibility, fermentation parameters, and microbial growth.

Science.gov (United States)

Martínez, M E; Ranilla, M J; Tejido, M L; Ramos, S; Carro, M D

2010-08-01

Four ruminally and duodenally cannulated sheep and 8 Rusitec fermenters were used to determine the effects of forage to concentrate (F:C) ratio and type of forage in the diet on ruminal fermentation and microbial protein synthesis. The purpose of the study was to assess how closely fermenters can mimic the dietary differences found in vivo. The 4 experimental diets contained F:C ratios of 70:30 or 30:70 with either alfalfa hay or grass hay as the forage. Microbial growth was determined in both systems using (15)N as a microbial marker. Rusitec fermenters detected differences between diets similar to those observed in sheep by changing F:C ratio on pH; neutral detergent fiber digestibility; total volatile fatty acid concentrations; molar proportions of acetate, propionate, butyrate, isovalerate, and caproate; and amylase activity. In contrast, Rusitec fermenters did not reproduce the dietary differences found in sheep for NH(3)-N and lactate concentrations, dry matter (DM) digestibility, proportions of isobutyrate and valerate, carboxymethylcellulase and xylanase activities, and microbial growth and its efficiency. Regarding the effect of the type of forage in the diet, Rusitec fermenters detected differences between diets similar to those found in sheep for most determined parameters, with the exception of pH, DM digestibility, butyrate proportion, and carboxymethylcellulase activity. Minimum pH and maximal volatile fatty acid concentrations were reached at 2h and at 6 to 8h postfeeding in sheep and fermenters, respectively, indicating that feed fermentation was slower in fermenters compared with that in sheep. There were differences between systems in the magnitude of most determined parameters. In general, fermenters showed lower lactate concentrations, neutral detergent fiber digestibility, acetate:propionate ratios, and enzymatic activities. On the contrary, fermenters showed greater NH(3)-N concentrations, DM digestibility, and proportions of propionate

Biohydrogen from thermophilic co-fermentation of swine manure with fruit and vegetable waste: maximizing stable production without pH control.

Science.gov (United States)

Tenca, A; Schievano, A; Perazzolo, F; Adani, F; Oberti, R

2011-09-01

Hydrogen production by dark fermentation may suffer of inhibition or instability due to pH deviations from optimality. The co-fermentation of promptly degradable feedstock with alkali-rich materials, such as livestock wastes, may represent a feasible and easy to implement approach to avoid external adjustments of pH. Experiments were designed to investigate the effect of the mixing ratio of fruit-vegetable waste with swine manure with the aim of maximizing biohydrogen production while obtaining process stability through the endogenous alkalinity of manure. Fruit-vegetable/swine manure ratio of 35/65 and HRT of 2d resulted to give the highest production rate of 3.27 ± 0.51 L(H2)L(-1)d(-1), with a corresponding hydrogen yield of 126 ± 22 mL(H2)g(-1)(VS-added) and H2 content in the biogas of 42 ± 5%. At these operating conditions the process exhibited also one of the highest measured stability, with daily productions deviating for less than 14% from the average. Copyright © 2011 Elsevier Ltd. All rights reserved.

The Effect of Saccharomyces Strains and Fermentation Condition on the pH, Foam Property and CO2 Concentration of Non-alcoholic Beer (Ma-al-shaeer

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S. Sohrabvandi

2014-12-01

Full Text Available This study aims to determine the effect of fermentation condition and Saccharomyces strains on the pH, foam property and CO2 concentration of non-alcoholic beer (Ma-al-shaeer. For this, the beer samples were inoculated with four different species of Saccharomyces (Saccharomyces rouxii 70531, S. rouxii 70535, S. ludwigii 3447 and S. cerevisiae 70424 and fermented for 48h in both aerobic and periodic aeration at three different temperatures. Then their pH, CO2 concentration and foam property were analyzed in 12h intervals during 48h fermentation. The results shows that the treatments with 4×107 CFU.ml-1 and periodic aeration at 24˚C showed the greatest decrease in pH, and the treatments with 107 CFU.ml-1 and aerobic-periodic aeration at 4˚C showed the lowest decrease in pH. The highest and lowest amounts of CO2 and foam property were obtained in the treatments with 4×107 CFU.ml-1 inoculation, aerobic condition, and the treatments with 107 CFU.ml-1, periodic aeration, respectively. These results further demonstrated that the highest drop in pH, and the highest ability of producing CO2 and foam were for S. cerevisiae 70424, and the lowest belonged to S. rouxii 70531. The overall outcome of the study points to the fact that physico-chemical properties of Ma-al-shaeer is important from the consumers' point of view. Therefore, S. cerevisiae with 4×107 CFU.ml-1 inoculation and aerobic condition at 4˚C has promising potential for producing Ma-al-shaeer with good physicochemical properties.

Colonic fermentation influences lower esophageal sphincter function in gastroesophageal reflux disease

DEFF Research Database (Denmark)

Piche, Thierry; des Varannes, Stanislas Bruley; Sacher-Huvelin, Sylvie

2003-01-01

BACKGROUND & AIMS: Colonic fermentation of carbohydrates is known to influence gastric and esophageal motility in healthy subjects. This study investigated the effects of colonic fermentation induced by oral administration of fructooligosaccharides (FOS) in patients with gastroesophageal reflux...... were monitored. RESULTS: Compared with placebo, FOS led to a significant increase in the number of transient lower esophageal sphincter relaxations (TLESRs) and reflux episodes, esophageal acid exposure, and the symptom score for GERD. The integrated plasma response of GLP-1 was significantly higher...... after FOS than placebo. CONCLUSIONS: Colonic fermentation of indigestible carbohydrates increases the rate of TLESRs, the number of acid reflux episodes, and the symptoms of GERD. Although different mechanisms are likely to be involved, excess release of GLP-1 may account, at least in part...

Reduction of verotoxigenic Escherichia coli in production of fermented sausages.

Science.gov (United States)

Holck, Askild L; Axelsson, Lars; Rode, Tone Mari; Høy, Martin; Måge, Ingrid; Alvseike, Ole; L'abée-Lund, Trine M; Omer, Mohamed K; Granum, Per Einar; Heir, Even

2011-11-01

After a number of foodborne outbreaks of verotoxigenic Escherichia coli involving fermented sausages, some countries have imposed regulations on sausage production. For example, the US Food Safety and Inspection Service requires a 5 log(10) reduction of E. coli in fermented products. Such regulations have led to a number of studies on the inactivation of E. coli in fermented sausages by changing processing and post-processing conditions. Several factors influence the survival of E. coli such as pre-treatment of the meat, amount of NaCl, nitrite and lactic acid, water activity, pH, choice of starter cultures and addition of antimicrobial compounds. Also process variables like fermentation temperature and storage time play important roles. Though a large variety of different production processes of sausages exist, generally the reduction of E. coli caused by production is in the range 1-2 log(10). In many cases this may not be enough to ensure microbial food safety. By optimising ingredients and process parameters it is possible to increase E. coli reduction to some extent, but in some cases still other post process treatments may be required. Such treatments may be storage at ambient temperatures, specific heat treatments, high pressure processing or irradiation. HACCP analyses have identified the quality of the raw materials, low temperature in the batter when preparing the sausages and a rapid pH drop during fermentation as critical control points in sausage production. This review summarises the literature on the reduction verotoxigenic E. coli in production of fermented sausages. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effect of mixing during fermentation in yogurt manufacturing.

Science.gov (United States)

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

2008-12-01

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

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

Science.gov (United States)

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

2018-02-01

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

Effect of alcoholic fermentation on the quality of grape brandies

Directory of Open Access Journals (Sweden)

Vukosavljević Vera

2015-01-01

Full Text Available Grape brandy is a product obtained by fermentation and distillation of crushed grapes of cultivated grapevine Vitis vinifera. Grape brandy quality depends on many factors such as: grapevine varieties, climate, soil, time and method of distillation, storage methods and other distillates. The grapevine variety 'Neoplanta' grown in the experimental field of the PD 'Center for Viticulture and Enology' in Niš was used in the experiment. Tests were performed in the laboratory of the Centre. Healthy grapes of harvest maturity were squashed by a stalk-removing electric crusher. Fermentation was performed in plastic containers in the presence of the indigenous microflora of wine yeasts. This paper presents the influence of pH and inorganic nitrogen added to the fermentation medium on the content of volatile components and concentrations of higher alcohols.

Ruminant Nutrition Symposium: Role of fermentation acid absorption in the regulation of ruminal pH.

Science.gov (United States)

Aschenbach, J R; Penner, G B; Stumpff, F; Gäbel, G

2011-04-01

Highly fermentable diets are rapidly converted to organic acids [i.e., short-chain fatty acids (SCFA) and lactic acid] within the rumen. The resulting release of protons can constitute a challenge to the ruminal ecosystem and animal health. Health disturbances, resulting from acidogenic diets, are classified as subacute and acute acidosis based on the degree of ruminal pH depression. Although increased acid production is a nutritionally desired effect of increased concentrate feeding, the accumulation of protons in the rumen is not. Consequently, mechanisms of proton removal and their quantitative importance are of major interest. Saliva buffers (i.e., bicarbonate, phosphate) have long been identified as important mechanisms for ruminal proton removal. An even larger proportion of protons appears to be removed from the rumen by SCFA absorption across the ruminal epithelium, making efficiency of SCFA absorption a key determinant for the individual susceptibility to subacute ruminal acidosis. Proceeding initially from a model of exclusively diffusional absorption of fermentation acids, several protein-dependent mechanisms have been discovered over the last 2 decades. Although the molecular identity of these proteins is mostly uncertain, apical acetate absorption is mediated, to a major degree, via acetate-bicarbonate exchange in addition to another nitrate-sensitive, bicarbonate-independent transport mechanism and lipophilic diffusion. Propionate and butyrate also show partially bicarbonate-dependent transport modes. Basolateral efflux of SCFA and their metabolites has to be mediated primarily by proteins and probably involves the monocarboxylate transporter (MCT1) and anion channels. Although the ruminal epithelium removes a large fraction of protons from the rumen, it also recycles protons to the rumen via apical sodium-proton exchanger, NHE. The latter is stimulated by ruminal SCFA absorption and salivary Na(+) secretion and protects epithelial integrity. Finally

Changes in physical and chemical characteristics of fermented cocoa(Theobroma cacaobeans with manual and semi-mechanized transfer, between fermentation boxes

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Pedro. P. Peláez

2016-01-01

Full Text Available The aim of this study was to evaluate variation in the physical and chemical properties of fermented cocoa beans with cocoa beans transfer between wooden fermentation boxes manually (M and semi - mechanized (SM way. Mass temperature, moisture, pH, and total acidity of the cotyledon and pulp; the total polyphenol, anthocyanin, reducing sugar, theobromine, and caffeine content in fresh, fermented, and dried beans; and percentage of fermented beans and time required to move beans during fermentation were determined. The cocoa used grew in the Pachiza district of the San Martin region of Peru. Cocoa sampling w as each 0, 48, 72, 96, 120, 144, and 168 h of fermentation. The cocoa mass temperature was highest with both removal systems after 96 h of fermentation. M cotyledon and pulp samples had the highest moisture content and titratable acidity, while cotyledon a nd pulp pH with both systems were statistically equal. In contrast, fermented beans had a higher polyphenol, anthocyanin, reducing sugar, theobromine, and caffeine content with SM. SM produced the greatest amount of fermentation (91.67% and required the s hortest amount of time to move beans (78.56 min. In conclusion, the system of fermentation of cocoa beans with SM was faster and produced fermented grains with high chemical quality.

Influence of Temperature and Carbon Dioxide on Fermentation of Cabernet Sauvignon Must

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Jan Mavri

2003-01-01

Full Text Available In the process of wine fermentation temperature and the amount of carbon dioxide present represent parameters that can be easily monitored and controlled. The influence of variation of the process temperature and the fluxes of additional inlet gaseous carbon dioxide in Saccharomyces bayanus fermentation of Cabernet Sauvignon grape must on the accumulation of biomass and production of metabolites was studied. All experiments with temperature and redox potential control on-line were performed in a 10-litre laboratory stirred tank reactor. Metabolites of Saccharomyces bayanus fermentation comprising higher alcohols (1-propanol, 2-butanol, isoamyl alcohol, as well as reducing sugars, were measured off-line by gas and high pressure liquid chromatography.

Physiological functions at single-cell level of Lactobacillus spp. isolated from traditionally fermented cabbage in response to different pH conditions.

Science.gov (United States)

Olszewska, Magdalena A; Kocot, Aleksandra M; Łaniewska-Trokenheim, Łucja

2015-04-20

Changes in pH are significant environmental stresses that may be encountered by lactobacilli during fermentation processes or passage through the gastrointestinal tract. Here, we report the cell response of Lactobacillus spp. isolated from traditionally fermented cabbage subjected to acid/alkaline treatments at pH 2.5, 7.4 and 8.1, which represented pH conditions of the gastrointestinal tract. Among six isolates, four species of Lactobacillus plantarum and two of Lactobacillus brevis were identified by fluorescence in situ hybridization (FISH). The fluorescence-based strategy of combining carboxyfluorescein diacetate (CFDA) and propidium iodine (PI) into a dual-staining assay was used together with epifluorescence microscopy (EFM) and flow cytometry (FCM) for viability assessment. The results showed that the cells maintained esterase activity and membrane integrity at pH 8.1 and 7.4. There was also no loss of culturability as shown by plate counts. In contrast, the majority of 2.5 pH-treated cells had a low extent of esterase activity, and experienced membrane perturbation. For these samples, an extensive loss of culturability was demonstrated. Comparison of the results of an in situ assessment with that of the conventional culturing method has revealed that although part of the stressed population was unable to grow on the growth media, it was deemed viable using a CFDA/PI assay. However, there was no significant change in the cell morphology among pH-treated lactobacilli populations. These analyses are expected to be useful in understanding the cell response of Lactobacillus strains to pH stress and may facilitate future investigation into functional and industrial aspects of this response. Copyright © 2015 Elsevier B.V. All rights reserved.

Ultrasonic characterization of yogurt fermentation process

OpenAIRE

IZBAIM , DRIS; FAIZ , BOUAZZA; MOUDDEN , ALI; MALAININE , MOHAMED; ABOUDAOUD , Idriss

2012-01-01

International audience; The objective of this work is to characterize the fermentation of yogurt based on an ultrasonic technique. Conventionally, the acidity of the yogurt is measured by a pH meter to determine the progress of fermentation. However, the pH meter should be cleaned and calibrated for each measurement and, therefore, this method is not practical. In this regard, ultrasonic techniques are fast, non-invasive and inexpensive. The measurement of ultrasonic parameters such as amplit...

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

Use of whey powder and skim milk powder for the production of fermented cream

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Ceren AKAL

2016-01-01

Full Text Available Abstract This study is about the production of fermented cream samples having 18% fat by addition of starter cultures. In order to partialy increase non-fat solid content of fermented cream samples, skim milk powder and demineralized whey powder in two different rates (50% and 70% were used. Samples were analyzed for changes in their biochemical and physicochemical properties (total solid, ash, fat, titratable acidity, pH value, total nitrogen, viscosity, tyrosine, acid number, peroxide and diacetyl values during 29-day of storage period. Samples tested consisted of 7 different groups; control group (without adding any powder, skim milk powder, 50% demineralized whey powder and 70% demineralized whey powder samples were in two different addition rate (2% and 4%. Also samples were analyzed for sensory properties. According to the results obtained, the addition of milk powder products affected titratable acidity and tyrosine values of fermented cream samples. Although powder addition and/or storage period didn’t cause significant variations in total solid, ash, fat, pH value, viscosity, acid number, peroxide, tyrosine and diacetyl values; sensory properties of fermented cream samples were influenced by both powder addition and storage period. Fermented cream containing 2% skim milk powder gets the top score of sensory evaluation among the samples.

Production of citrinin-free Monascus pigments by submerged culture at low pH.

Science.gov (United States)

Kang, Biyu; Zhang, Xuehong; Wu, Zhenqiang; Wang, Zhilong; Park, Sunghoon

2014-02-05

Microbial fermentation of citrinin-free Monascus pigments is of great interest to meet the demand of food safety. In the present work, the effect of various nitrogen sources, such as monosodium glutamate (MSG), cornmeal, (NH4)₂SO₄, and NaNO₃, on Monascus fermentation was examined under different initial pH conditions. The composition of Monascus pigments and the final pH of fermentation broth after Monascus fermentation were determined. It was found that nitrogen source was directly related to the final pH and the final pH regulated the composition of Monascus pigments and the biosynthesis of citrinin. Thus, an ideal nitrogen source can be selected to control the final pH and then the citrinin biosynthesis. Citrinin-free orange pigments were produced at extremely low initial pH in the medium with (NH4)₂SO₄ or MSG as nitrogen source. No citrinin biosynthesis at extremely low pH was further confirmed by extractive fermentation of intracellular pigments in the nonionic surfactant Triton X-100 micelle aqueous solution. This is the first report about the production of citrinin-free Monascus pigments at extremely low pH. Copyright © 2013 Elsevier Inc. All rights reserved.

Changes in physical and chemical characteristics of fermented cocoa (Theobroma cacao beans with manual and semi-mechanized transfer, between fermentation boxes

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Pedro. P. Peláez

2016-06-01

Full Text Available The aim of this study was to evaluate variation in the physical and chemical properties of fermented cocoa beans with cocoa beans transfer between wooden fermentation boxes manually (M and semi-mechanized (SM way. Mass temperature, moisture, pH, and total acidity of the cotyledon and pulp; the total polyphenol, anthocyanin, reducing sugar, theobromine, and caffeine content in fresh, fermented, and dried beans; and percentage of fermented beans and time required to move beans during fermentation were determined. The cocoa used grew in the Pachiza district of the San Martin region of Peru. Cocoa sampling was each 0, 48, 72, 96, 120, 144, and 168 h of fermentation. The cocoa mass temperature was highest with both removal systems after 96 h of fermentation. M cotyledon and pulp samples had the highest moisture content and titratable acidity, while cotyledon and pulp pH with both systems were statistically equal. In contrast, fermented beans had a higher polyphenol, anthocyanin, reducing sugar, theobromine, and caffeine content with SM. SM produced the greatest amount of fermentation (91.67% and required the shortest amount of time to move beans (78.56 min. In conclusion, the system of fermentation of cocoa beans with SM was faster and produced fermented grains with high chemical quality.

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

Science.gov (United States)

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

2012-02-01

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

Characterization of the Factors that Influence Sinapine Concentration in Rapeseed Meal during Fermentation

Science.gov (United States)

Niu, Yanxing; Jiang, Mulan; Guo, Mian; Wan, Chuyun; Hu, Shuangxi; Jin, Hu; Huang, Fenghong

2015-01-01

We analyzed and compared the difference in sinapine concentration in rapeseed meal between the filamentous fungus, Trametes sp 48424, and the yeast, Saccharomyces cerevisiae, in both liquid and solid-state fermentation. During liquid and solid-state fermentation by Trametes sp 48424, the sinapine concentration decreased significantly. In contrast, the liquid and solid-state fermentation process by Saccharomyces cerevisiae just slightly decreased the sinapine concentration (P ≤ 0.05). After the solid-state fermented samples were dried, the concentration of sinapine in rapeseed meal decreased significantly in Saccharomyces cerevisiae. Based on the measurement of laccase activity, we observed that laccase induced the decrease in the concentration of sinapine during fermentation with Trametes sp 48424. In order to eliminate the influence of microorganisms and the metabolites produced during fermentation, high moisture rapeseed meal and the original rapeseed meal were dried at 90°C and 105°C, respectively. During drying, the concentration of sinapine in high moisture rapeseed meal decreased rapidly and we obtained a high correlation coefficient between the concentration of sinapine and loss of moisture. Our results suggest that drying and enzymes, especially laccase that is produced during the solid-state fermentation process, may be the main factors that affect the concentration of sinapine in rapeseed meal. PMID:25606856

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

Science.gov (United States)

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

2018-03-01

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

Starmerella bombicola influences the metabolism of Saccharomyces cerevisiae at pyruvate decarboxylase and alcohol dehydrogenase level during mixed wine fermentation

Science.gov (United States)

2012-01-01

Background The use of a multistarter fermentation process with Saccharomyces cerevisiae and non-Saccharomyces wine yeasts has been proposed to simulate natural must fermentation and to confer greater complexity and specificity to wine. In this context, the combined use of S. cerevisiae and immobilized Starmerella bombicola cells (formerly Candida stellata) was assayed to enhance glycerol concentration, reduce ethanol content and to improve the analytical composition of wine. In order to investigate yeast metabolic interaction during controlled mixed fermentation and to evaluate the influence of S. bombicola on S. cerevisiae, the gene expression and enzymatic activity of two key enzymes of the alcoholic fermentation pathway such as pyruvate decarboxylase (Pdc1) and alcohol dehydrogenase (Adh1) were studied. Results The presence of S. bombicola immobilized cells in a mixed fermentation trial confirmed an increase in fermentation rate, a combined consumption of glucose and fructose, an increase in glycerol and a reduction in the production of ethanol as well as a modification in the fermentation of by products. The alcoholic fermentation of S. cerevisiae was also influenced by S. bombicola immobilized cells. Indeed, Pdc1 activity in mixed fermentation was lower than that exhibited in pure culture while Adh1 activity showed an opposite behavior. The expression of both PDC1 and ADH1 genes was highly induced at the initial phase of fermentation. The expression level of PDC1 at the end of fermentation was much higher in pure culture while ADH1 level was similar in both pure and mixed fermentations. Conclusion In mixed fermentation, S. bombicola immobilized cells greatly affected the fermentation behavior of S. cerevisiae and the analytical composition of wine. The influence of S. bombicola on S. cerevisiae was not limited to a simple additive contribution. Indeed, its presence caused metabolic modifications during S. cerevisiae fermentation causing variation in the gene

Starmerella bombicola influences the metabolism of Saccharomyces cerevisiae at pyruvate decarboxylase and alcohol dehydrogenase level during mixed wine fermentation

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Milanovic Vesna

2012-02-01

Full Text Available Abstract Background The use of a multistarter fermentation process with Saccharomyces cerevisiae and non-Saccharomyces wine yeasts has been proposed to simulate natural must fermentation and to confer greater complexity and specificity to wine. In this context, the combined use of S. cerevisiae and immobilized Starmerella bombicola cells (formerly Candida stellata was assayed to enhance glycerol concentration, reduce ethanol content and to improve the analytical composition of wine. In order to investigate yeast metabolic interaction during controlled mixed fermentation and to evaluate the influence of S. bombicola on S. cerevisiae, the gene expression and enzymatic activity of two key enzymes of the alcoholic fermentation pathway such as pyruvate decarboxylase (Pdc1 and alcohol dehydrogenase (Adh1 were studied. Results The presence of S. bombicola immobilized cells in a mixed fermentation trial confirmed an increase in fermentation rate, a combined consumption of glucose and fructose, an increase in glycerol and a reduction in the production of ethanol as well as a modification in the fermentation of by products. The alcoholic fermentation of S. cerevisiae was also influenced by S. bombicola immobilized cells. Indeed, Pdc1 activity in mixed fermentation was lower than that exhibited in pure culture while Adh1 activity showed an opposite behavior. The expression of both PDC1 and ADH1 genes was highly induced at the initial phase of fermentation. The expression level of PDC1 at the end of fermentation was much higher in pure culture while ADH1 level was similar in both pure and mixed fermentations. Conclusion In mixed fermentation, S. bombicola immobilized cells greatly affected the fermentation behavior of S. cerevisiae and the analytical composition of wine. The influence of S. bombicola on S. cerevisiae was not limited to a simple additive contribution. Indeed, its presence caused metabolic modifications during S. cerevisiae fermentation

Influence of polysorbate 80 and cyclopropane fatty acid synthase activity on lactic acid production by Lactobacillus casei ATCC 334 at low pH.

Science.gov (United States)

Broadbent, J R; Oberg, T S; Hughes, J E; Ward, R E; Brighton, C; Welker, D L; Steele, J L

2014-03-01

Lactic acid is an important industrial chemical commonly produced through microbial fermentation. The efficiency of acid extraction is increased at or below the acid's pKa (pH 3.86), so there is interest in factors that allow for a reduced fermentation pH. We explored the role of cyclopropane synthase (Cfa) and polysorbate (Tween) 80 on acid production and membrane lipid composition in Lactobacillus casei ATCC 334 at low pH. Cells from wild-type and an ATCC 334 cfa knockout mutant were incubated in APT broth medium containing 3 % glucose plus 0.02 or 0.2 % Tween 80. The cultures were allowed to acidify the medium until it reached a target pH (4.5, 4.0, or 3.8), and then the pH was maintained by automatic addition of NH₄OH. Cells were collected at the midpoint of the fermentation for membrane lipid analysis, and media samples were analyzed for lactic and acetic acids when acid production had ceased. There were no significant differences in the quantity of lactic acid produced at different pH values by wild-type or mutant cells grown in APT, but the rate of acid production was reduced as pH declined. APT supplementation with 0.2 % Tween 80 significantly increased the amount of lactic acid produced by wild-type cells at pH 3.8, and the rate of acid production was modestly improved. This effect was not observed with the cfa mutant, which indicated Cfa activity and Tween 80 supplementation were each involved in the significant increase in lactic acid yield observed with wild-type L. casei at pH 3.8.

Influence de la fermentation et du séchage solaire sur l'acquisition du pouvoir de panification de l'amidon aigre de manioc = Influence of fermentation and sun-drying on the breadmaking capacity of cassava sour starch

OpenAIRE

Dufour, D.; Brabet, C.; Zakhia, N.; Chuzel, G.

1995-01-01

L'amidon aigre de manioc, traditionnellement fermenté et séché au soleil, présente un pouvoir de panification. Cette étude porte sur l'évolution des propriétés physicochimiques et fonctionnelles de l'amidon aigre de manioc, au cours de la fermentation et du séchage au soleil, afin de corréler ces propriétés au pouvoir de panification. La mesure de pH, le dosage d'acidité totale et d'acide lactique produit, l'établissement des viscoamylogrammes et la détermination du pouvoir de panification on...

Production of citric acid from whey permeate by fermentation using Aspergillus niger

Energy Technology Data Exchange (ETDEWEB)

Hossain, M; Brooks, J D

1983-08-01

The use of lactic casein whey permeate as a substrate for citric acid production by fermentation has been investigated. Using a mutant strain of Aspergillus niger IMI 41874 in fermenter culture, a citric acid concentration of 8.3 g/l, representing a yield of 19% (w/w) based on lactose utilized, has been observed. Supplementation of the permeate with lactose (final concentration 140 g/l) increased the production to 14.8 g/l (yield 23%). The natural pH of the permeate (pH 4.5) was the most suitable initial pH for the process, and pH control during the fermentation was unnecessary. The addition of methanol (final concentration 3% v/v) to the fermentation increased the citric acid production to 25 g/l (yield 33%, based on lactose utilized). 13 references.

The influence of nitrogen and biotin interactions on the performance of Saccharomyces in alcoholic fermentations.

Science.gov (United States)

Bohlscheid, J C; Fellman, J K; Wang, X D; Ansen, D; Edwards, C G

2007-02-01

To study the impact of assimilable nitrogen, biotin and their interaction on growth, fermentation rate and volatile formation by Saccharomyces. Fermentations of synthetic grape juice media were conducted in a factorial design with yeast assimilable nitrogen (YAN) (60 or 250 mg l(-1)) and biotin (0, 1 or 10 microg l(-1)) as variables. All media contained 240 g l(-1) glucose + fructose (1 : 1) and were fermented using biotin-depleted Saccharomyces cerevisiae strains EC1118 or UCD 522. Both strains exhibited weak growth and sluggish fermentation rates without biotin. Increased nitrogen concentration resulted in higher maximum fermentation rates, while adjusting biotin from 1 to 10 microg l(-1) had no effect. Nitrogen x biotin interactions influenced fermentation time, production of higher alcohols and hydrogen sulfide (H(2)S). Maximum H(2)S production occurred in the medium containing 60 mg l(-1) YAN and 1 microg l(-1) biotin. Nitrogen x biotin interactions affect fermentation time and volatile production by Saccharomyces depending on strain. Biotin concentrations sufficient to complete fermentation may affect the organoleptic impact of wine. This study demonstrates the necessity to consider nutrient interactions when diagnosing problem fermentations.

Is there a potential consumer market for low-sodium fermented sausages?

Science.gov (United States)

Dos Santos, Bibiana A; Campagnol, Paulo C B; da Cruz, Adriano G; Morgano, Marcelo A; Wagner, Roger; Pollonio, Marise A R

2015-05-01

The NaCl levels in dry fermented sausages were reduced by 50% or were substituted with KCl, CaCl2 , or a blend of KCl and CaCl2 (1:1). The quality, safety, and the potential consumer market of dry fermented sausages were assessed. Neither 50% reduction of the NaCl content nor the substitution of 50% of the NaCl with KCl influenced the fermentation and maturation process. However, when CaCl2 was used as the substitute salt (50%), there was a significant decrease in pH, an increase in the water activity, and a decrease in lactic acid and micrococcus bacterial counts. Overall, the sensory acceptance decreased in dry fermented sausages with reduced sodium content. However, cluster analysis and internal preference mapping revealed potential for commercialization of samples with 50% of the NaCl content substituted with KCl or with a mixture of KCl and CaCl2 (1:1). © 2015 Institute of Food Technologists®

(ajst) influence of fermentation and cowpea

African Journals Online (AJOL)

opiyo

Statgraphics (Graphics Software System, STCC, Inc. U.S.A). Comparisons .... 7 2. 0.473. 0.597. 1.056. 0.14. Co-fermentation. Fermented maize and cowpea blends showed varied effects ...... Oligosaccharides in eleven Legumes and their air-.

Influence of temperature, pH and yeast on in-field production of ethanol from unsterilized sweet sorghum juice

Energy Technology Data Exchange (ETDEWEB)

Kundiyana, Dimple K.; Bellmer, Danielle D.; Huhnke, Raymond L.; Wilkins, Mark R. [Department of Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater, OK 74078 (United States); Claypool, P.L. [Department of Statistics, Oklahoma State University, Stillwater, OK 74078 (United States)

2010-10-15

It is inevitable that ethanol production in the United States will continue to increase. Sweet sorghum has the potential to be used as a renewable energy crop, and is a viable candidate for ethanol production. Previous barriers to commercialization of sweet sorghum to ethanol have primarily been the high capital cost involved in building a central processing plant that may be operated only seasonally. In order to reduce the investment necessary in a central processing facility, the proposed process involves in-field production of ethanol from sweet sorghum. The overall objective of the research was to determine whether fermentation can take place in the environment with no process control. The goals were to evaluate the effects of yeast type, pH, and nutrients on fermentation process efficiency. Results indicated that both strains of Saccharomyces cerevisiae tested were able to perform fermentation within a wide ambient temperature range (10-25 C). Maximum ethanol produced was 7.9% w v{sup -1} in 120 h under ambient temperature conditions. Other process variables such as adding urea or lowering pH did not significantly improve the sugar to ethanol conversion efficiency of yeasts. Results indicate that in-field fermentation of sweet sorghum juice to ethanol is possible with minimal or no process controls and is a feasible process for ethanol production. (author)

Fermentation of melon seeds for “Ogiri egusi” as affected by fermentation variables using Bacillus subtilis

Directory of Open Access Journals (Sweden)

Ogueke, C. C.

2013-12-01

Full Text Available Aims: Manipulation of fermentation variables during ‘Ogiri egusi’ production using Bacillus subtilis was studied with the view to improving the fermentation process and quality of product. The variables studied were relative humidity (RH, temperature and pore size of wrapping material. Methodology and results: Effect of variables on amino nitrogen, pH and peroxide value was determined on 24 h basis for 96 h. Attempt on optimization of process using response surface method was made. Amino nitrogen increased with fermentation time, the highest value (6.25 mg N/g being obtained from sample fermented at 75% RH, temperature 35 °C and 90 µm pore size of wrapping material. Fermentation attained its peak at 48 h fermentation time. pH increased into the alkaline range within the period, the highest value (7.81 being from sample that gave the highest amount of amino nitrogen. Peroxide values obtained in all samples were far below the recommended value of 30 Meq/kg. However, the highest value (4.16 Keq/kg was obtained in sample fermented at 85% RH, temperature 30 °C and 70 µm pore size of wrapper. Statistical analysis and response surface plots associated with analysis showed that the quadratic effect of variables was significant (p = 0.05. Effects of relative humidity and pore size of wrapping material were also significant and accounted for 99.56% of the amino nitrogen variation. Conclusion, significance and impact study: Manipulation of the fermentation variables significantly improved the process. Thus use of response surface method optimized the fermentation process especially the effects of relative humidity and pore size of wrapping materials. The suggested combination of variables for optimum fermentation is 75% RH, temperature 35 °C and 70 µm pore size of wrapper. This ultimately will improve product quality and reduce fermentation time.

Measurement of pH micro-heterogeneity in natural cheese matrices by flourescence lifetime imaging

OpenAIRE

Burdikova, Suzana; Svindrych, Zdenek; Pala, Jan; Hickey, Cian D; Wilkinson, Martin G.; Panek, Jiri; Auty, Mark A.E.; Periasamy, Ammasi; Sheehan, Jeremiah J.

2015-01-01

peer-reviewed Cheese, a product of microbial fermentation may be defined as a protein matrix entrapping fat, moisture, minerals and solutes as well as dispersed bacterial colonies. The growth and physiology of bacterial cells in these colonies may be influenced by the microenvironment around the colony, or alternatively the cells within the colony may modify the microenvironment (e.g., pH, redox potential) due to their metabolic activity. While cheese pH may be measured at macro level ther...

Influences of environmental and operational factors on dark fermentative hydrogen production: a review

International Nuclear Information System (INIS)

Mohammadi, Parviz; Ibrahim, Shaliza; Ghafari, Shahin; Annuar, Mohamad Suffian Mohamad; Vikineswary, Sabaratnam; Zinatizadeh, Ali Akbar

2012-01-01

Hydrogen (H 2 ) is one of renewable energy sources known for its non-polluting and environmentally friendly nature, as its end combustion product is water (H 2 O). The biological production of H 2 is a less energy intensive alternative where processes can be operated at ambient temperature and pressure. Dark fermentation by bacterial biomass is one of multitude of approaches to produce hydrogen which is known as the cleanest renewable energy and is thus receiving increasing attention worldwide. The present study briefly reviews the biohydrogen production process with special attention on the effects of several environmental and operational factors towards the process. Factors such as organic loading rate, hydraulic retention time, temperature, and pH studied in published reports were compared and their influences are discussed in this work. This review highlights the variations in examined operating ranges for the factors as well as their reported optimum values. Divergent values observed for the environmental/operational factors merit further exploration in this field. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Influences of environmental and operational factors on dark fermentative hydrogen production: a review

Energy Technology Data Exchange (ETDEWEB)

Mohammadi, Parviz [Department of Civil Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur (Malaysia); Department of Environmental Health Engineering, Faculty of Health, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Ibrahim, Shaliza; Ghafari, Shahin [Department of Civil Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur (Malaysia); Annuar, Mohamad Suffian Mohamad; Vikineswary, Sabaratnam [Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur (Malaysia); Zinatizadeh, Ali Akbar [Department of Applied Chemistry, Faculty of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Water and Wastewater Research Center (WWRC), Razi University, Kermanshah (Iran, Islamic Republic of)

2012-11-15

Hydrogen (H{sub 2}) is one of renewable energy sources known for its non-polluting and environmentally friendly nature, as its end combustion product is water (H{sub 2}O). The biological production of H{sub 2} is a less energy intensive alternative where processes can be operated at ambient temperature and pressure. Dark fermentation by bacterial biomass is one of multitude of approaches to produce hydrogen which is known as the cleanest renewable energy and is thus receiving increasing attention worldwide. The present study briefly reviews the biohydrogen production process with special attention on the effects of several environmental and operational factors towards the process. Factors such as organic loading rate, hydraulic retention time, temperature, and pH studied in published reports were compared and their influences are discussed in this work. This review highlights the variations in examined operating ranges for the factors as well as their reported optimum values. Divergent values observed for the environmental/operational factors merit further exploration in this field. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Production of lactic acid from corn cobs through fermentation lactobacillus delbruekii

International Nuclear Information System (INIS)

Ali, Z.; Anjum, M.; Zahoor, T.

2007-01-01

Corn cobs were used as the source of reducing sugars for conversion into lactic acid through fermentation by a local strain of Lactobacillus delbruekii, under varying parameters of time, temperature, pH and glucose concentration, The production of lactic acid significantly increased with increase in Ph, fermentation time and glucose concentration (1-5%) and was significantly high (8.40 g/1) at pH 6, while significantly low (7.67 g/1) at pH 5. (author)

The water kefir grain inoculum determines the characteristics of the resulting water kefir fermentation process.

Science.gov (United States)

Laureys, D; De Vuyst, L

2017-03-01

To investigate the influence of the water kefir grain inoculum on the characteristics of the water kefir fermentation process. Three water kefir fermentation processes were started with different water kefir grain inocula and followed as a function of time regarding microbial species diversity, community dynamics, substrate consumption profile and metabolite production course. The inoculum determined the water kefir grain growth, the viable counts on the grains, the time until total carbohydrate exhaustion, the final metabolite concentrations and the microbial species diversity. There were always 2-10 lactic acid bacterial cells for every yeast cell and the majority of these micro-organisms was always present on the grains. Lactobacillus paracasei, Lactobacillus hilgardii, Lactobacillus nagelii and Saccharomyces cerevisiae were always present and may be the key micro-organisms during water kefir fermentation. Low water kefir grain growth was associated with small grains with high viable counts of micro-organisms, fast fermentation and low pH values, and was not caused by the absence of exopolysaccharide-producing lactic acid bacteria. The water kefir grain inoculum influences the microbial species diversity and characteristics of the fermentation process. A select group of key micro-organisms was always present during fermentation. This study allows a rational selection of a water kefir grain inoculum. © 2016 The Society for Applied Microbiology.

The Brewing Process: Optimizing the Fermentation

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Teodora Coldea

2014-11-01

Full Text Available Beer is a carbonated alcoholic beverage obtained by alcoholic fermentation of malt wort boiled with hops. Brown beer obtained at Beer Pilot Station of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca was the result of a recipe based on blond, caramel and black malt in different proportions, water, hops and yeast. This study aimed to monitorize the evolution of wort in primary and secondary alcoholic fermentation in order to optimize the process. Two wort batches were assambled in order to increase the brewing yeast fermentation performance. The primary fermentation was 14 days, followed by another 14 days of secondary fermentation (maturation. The must fermentation monitoring was done by the automatic FermentoStar analyzer. The whole fermentation process was monitorized (temperature, pH, alcohol concentration, apparent and total wort extract.

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.

Production and Characterization of Lipases by Two New Isolates of Aspergillus through Solid-State and Submerged Fermentation

Science.gov (United States)

Colla, Luciane Maria; Ficanha, Aline M. M.; Rizzardi, Juliana; Bertolin, Telma Elita; Reinehr, Christian Oliveira; Costa, Jorge Alberto Vieira

2015-01-01

Due to the numerous applications of lipases in industry, there is a need to study their characteristics, because lipases obtained from different sources may present different properties. The aim of this work was to accomplish the partial characterization of lipases obtained through submerged fermentation and solid-state fermentation by two species of Aspergillus. Fungal strains were isolated from a diesel-contaminated soil and selected as good lipases producers. Lipases obtained through submerged fermentation presented optimal activities at 37°C and pH 7.2 and those obtained through solid-state fermentation at 35°C and pH 6.0. The enzymes produced by submerged fermentation were more temperature-stable than those obtained by solid-state fermentation, presenting 72% of residual activity after one hour of exposition at 90°C. Lipases obtained through submerged fermentation had 80% of stability in acidic pH and those obtained through solid-state fermentation had stability greater than 60% in alkaline pH. PMID:26180809

Production and Characterization of Lipases by Two New Isolates of Aspergillus through Solid-State and Submerged Fermentation

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Luciane Maria Colla

2015-01-01

Full Text Available Due to the numerous applications of lipases in industry, there is a need to study their characteristics, because lipases obtained from different sources may present different properties. The aim of this work was to accomplish the partial characterization of lipases obtained through submerged fermentation and solid-state fermentation by two species of Aspergillus. Fungal strains were isolated from a diesel-contaminated soil and selected as good lipases producers. Lipases obtained through submerged fermentation presented optimal activities at 37°C and pH 7.2 and those obtained through solid-state fermentation at 35°C and pH 6.0. The enzymes produced by submerged fermentation were more temperature-stable than those obtained by solid-state fermentation, presenting 72% of residual activity after one hour of exposition at 90°C. Lipases obtained through submerged fermentation had 80% of stability in acidic pH and those obtained through solid-state fermentation had stability greater than 60% in alkaline pH.

Influence of temperature and glucose addition on growth and survival of bacteria from BCT culture in soymilk

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Galja Pletikapić

2008-05-01

Full Text Available Soymilk was fermented using culture composed of Lactobacillus casei, Bifidobacterium spp. and Streptococcus thermophilus (BCT culture, Chr. Hansen’s, Denmark at two temperatures 37 °C and 41 °C with and without 5 % of glucose addition. Fermentation was conducted until pH value 4.6 was reached. During fermentation and storage time (28 days at +4 °C changes of pH values and viable cells counts were observed. All fermentations lasted between 6 and 7.5 hours. At temperature 41 °C fermentation was approximately 1 hour shorter, while glucose addition had reduced fermentation time for 30 minutes. Higher temperature of fermentation, as well as glucose addition, had negligible influence on portions and viable cells count of particular bacterial species in the product. In all fermented soymilk samples the viable cells count of particular bacterial strains was roughly equal: Str. thermophilus have grown the best (~ 108 CFU/mL while lactobacilli have grown the weakest (~ 105 - 106 CFU/mL. Generally, for soymilk fermentation mainly Str. thermophilus was responsible. On its growth rate glucose addition and higher fermentation temperature had strong positive influence. During 28 days of refrigerated storage, the product was stable. A remarkable decrease of viable cells count of lactobacilli was noticed in the last week of storage.

Production of Star Fruit Alcoholic Fermented Beverage.

Science.gov (United States)

Valim, Flávia de Paula; Aguiar-Oliveira, Elizama; Kamimura, Eliana Setsuko; Alves, Vanessa Dias; Maldonado, Rafael Resende

2016-12-01

Star fruit ( Averrhoa carambola ) is a nutritious tropical fruit. The aim of this study was to evaluate the production of a star fruit alcoholic fermented beverage utilizing a lyophilized commercial yeast ( Saccharomyces cerevisiae ). The study was conducted utilizing a 2 3 central composite design and the best conditions for the production were: initial soluble solids between 23.8 and 25 °Brix (g 100 g -1 ), initial pH between 4.8 and 5.0 and initial concentration of yeast between 1.6 and 2.5 g L -1 . These conditions yielded a fermented drink with an alcohol content of 11.15 °GL (L 100 L -1 ), pH of 4.13-4.22, final yeast concentration of 89 g L -1 and fermented yield from 82 to 94 %. The fermented drink also presented low levels of total and volatile acidities.

Microbial Ecology and Process Technology of Sourdough Fermentation.

Science.gov (United States)

De Vuyst, Luc; Van Kerrebroeck, Simon; Leroy, Frédéric

2017-01-01

From a microbiological perspective, sourdough is to be considered as a specific and stressful ecosystem, harboring yeasts and lactic acid bacteria (LAB), that is used for the production of baked goods. With respect to the metabolic impact of the sourdough microbiota, acidification (LAB), flavor formation (LAB and yeasts), and leavening (yeasts and heterofermentative LAB species) are most noticeable. Three distinct types of sourdough fermentation processes can be discerned based on the inocula applied, namely backslopped ones (type 1), those initiated with starter cultures (type 2), and those initiated with a starter culture followed by backslopping (type 3). A sourdough-characteristic LAB species is Lactobacillus sanfranciscensis. A sourdough-characteristic yeast species is Candida humilis. Although it has been suggested that the microbiota of a specific sourdough may be influenced by its geographical origin, region specificity often seems to be an artefact resulting from interpretation of the research data, as those are dependent on sampling, isolation, and identification procedures. It is however clear that sourdough-adapted microorganisms are able to withstand stress conditions encountered during their growth. Based on the technological setup, type 0 (predoughs), type I (artisan bakery firm sourdoughs), type II (industrial liquid sourdoughs), and type III sourdoughs (industrial dried sourdoughs) can be distinguished. The production of all sourdoughs, independent of their classification, depends on several intrinsic and extrinsic factors. Both the flour (type, quality status, etc.) and the process parameters (fermentation temperature, pH and pH evolution, dough yield, water activity, oxygen tension, backslopping procedure and fermentation duration, etc.) determine the dynamics and outcome of (backslopped) sourdough fermentation processes. Copyright © 2017 Elsevier Inc. All rights reserved.

Fermentation value of molasses for the alcohol industry

Energy Technology Data Exchange (ETDEWEB)

Sobkiewicz, G

1963-01-01

Molasses of pH 7 to 8 containing invert sugar in quantity not exceeding 1% showed the highest fermentation value. The purity coefficient should not exceed 56%, since non-sugars, minerals, and nitrogen compounds stimulated fermentation.

Quality and Composition of Red Wine Fermented with Schizosaccharomyces pombe as Sole Fermentative Yeast, and in Mixed and Sequential Fermentations with Saccharomyces cerevisiae

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Felipe Palomero

2014-01-01

Full Text Available This work examines the physiology of Schizosaccharomyces pombe (represented by strain 938 in the production of red wine, as the sole fermentative yeast, and in mixed and sequential fermentations with Saccharomyces cerevisiae 796. For further comparison, fermentations in which Saccharomyces cerevisiae was the sole fermentative yeast were also performed; in these fermentations a commercial lactic acid bacterium was used to perform malolactic fermentation once alcoholic fermentation was complete (unlike S. cerevisiae, the Sc. pombe performs maloalcoholic fermentation and therefore removes malic acid without such help. Relative density, acetic, malic and pyruvic acid concentrations, primary amino nitrogen and urea concentrations, and pH of the musts were measured over the entire fermentation period. In all fermentations in which Sc. pombe 938 was involved, nearly all the malic acid was consumed from an initial concentration of 5.5 g/L, and moderate acetic acid concentrations below 0.4 g/L were formed. The urea content of these wines was notably lower, showing a tenfold reduction when compared with those that were made with S. cerevisiae 796 alone. The sensorial properties of the different final wines varied widely. The wines fermented with Sc. pombe 938 had maximum aroma intensity and quality, and they were preferred by the tasters.

Antioxidant Activity of Whey from Milk Fermented with Lactobacillus Species Isolated from Nigerian Fermented Foods

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Ifeoma Korie

2010-01-01

Full Text Available Eight Lactobacillus isolates obtained from five indigenous fermented foods (ogi, ogi baba, wara, kunnu and ugba were investigated. Wara is a dairy-based food while the others are not dairy-based. The bacteria were isolated on MRS agar and purified by successive streaking on the same medium. The whey fraction of skimmed milk fermented with each isolate was assayed for radical scavenging effects using 2,2-diphenyl-1-picrylhydrazyl (DPPH radical. All the whey fractions showed radical scavenging activities. The five isolates with the highest activities were selected. On the basis of Gram stain reaction, cellular morphology, biochemical tests and carbohydrate utilization profiles they were identified as strains of Lactobacillus brevis, L. fermentum, L. plantarum, L. casei and L. delbrueckii. The antioxidant activities of whey fractions from 24-hour fermentations with the selected organisms were investigated using both radical scavenging effects and lipid peroxidation inhibitory activity. The radical scavenging activity was generally higher than the lipid peroxidation inhibition, except in the L. plantarum strain, which did not show any significant difference in both activities. The probiotic potential of the isolates was evaluated by pH and bile tolerance. None of the selected isolates showed any growth at pH=2.0 but L. casei and L. delbrueckii survived at this pH. Four of the five selected isolates were able to grow in 0.5 % dehydrated bile, with L. casei strain showing the highest level of growth, followed by L. delbrueckii. L. plantarum strain was not bile tolerant. The ability of L. casei and L. delbrueckii strains to survive at pH=2 and grow in the presence of bile indicates that the isolates may be able to colonize the gastrointestinal tract. The findings of this study indicate that Lactobacillus strains isolated from indigenous Nigerian fermented foods could be useful as starter cultures to provide antioxidants in food and that fermented milk

Measurement of pH micro-heterogeneity in natural cheese matrices by fluorescence lifetime imaging

OpenAIRE

Zuzana eBurdikova; Zdenek eSvindrych; Jan ePala; Cian eHickey; Martin G. Wilkinson; Jiri ePanek; Mark A. E. Auty; Ammasi ePeriasamy; Jeremiah J. Sheehan

2015-01-01

Cheese, a product of microbial fermentation may be defined as a protein matrix entrapping fat, moisture, minerals and solutes as well as dispersed bacterial colonies. The growth and physiology of bacterial cells in these colonies may be influenced by the microenvironment around the colony, or alternatively the cells within the colony may modify the microenvironment (e.g., pH, redox potential) due to their metabolic activity. While cheese pH may be measured at macro level there remains a signi...

Screening for the effects of natural plant extracts at different pH on in vitro rumen microbial fermentation of a high-concentrate diet for beef cattle.

Science.gov (United States)

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

2005-11-01

Six natural plant extracts and three secondary plant metabolites were tested at five doses (0, 0.3, 3, 30, and 300 mg/L) and two different pH (7.0 and 5.5) in a duplicate 9 x 5 x 2 factorial arrangement of treatments to determine their effects on in vitro microbial fermentation using ruminal fluid from heifers fed a high-concentrate finishing diet. Treatments were extracts of garlic (GAR), cinnamon (CIN), yucca (YUC), anise (ANI), oregano (ORE), and capsicum (CAP) and pure cinnamaldehyde (CDH), anethole (ATL), and eugenol (EUG). Each treatment was tested in triplicate and in two periods. Fifty milliliters of a 1:1 ruminal fluid-to-buffer solution were introduced into polypropylene tubes supplied with 0.5 g of DM of a 10:90 forage:concentrate diet (15.4% CP, 16.0% NDF; DM basis) and incubated for 24 h at 39 degrees C. Samples were collected for ammonia N and VFA concentrations. The decrease in pH from 7.0 to 5.5 resulted in lower (P cattle diets may differ depending on ruminal pH. When pH was 5.5, GAR, CAP, YUC, and CDH altered ruminal microbial fermentation in favor of propionate, which is more energetically efficient.

New inoculants on maize silage fermentation

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Fábia Giovana do Val de Assis

2014-08-01

Full Text Available The objective of this study was to evaluate the effect of bacterial inoculants at two inoculation rates on chemical and biological characteristics of maize silage. The treatments consisted of two inoculating rates (5 and 6 log cfu g-1 of forage for each strain of lactic acid bacteria (LAB identified as Lactobacillus buchneri, L. hilgardii, or L. plantarum. The maize was ensiled in experimental PVC silos. Samples were taken for the determination of the contents of dry matter (DM, crude protein (CP, neutral detergent fiber (NDF, water-soluble carbohydrates (WSC, organic acids and alcohols, for the evaluation of the populations of lactic acid bacteria, yeasts, filamentous fungi, and for the determination of pH values during ensilage and after 30 or 90 days of fermentation. The doses of inoculants did not promote significant differences on the evaluated characteristics. There was effect of inoculants on acetic acid, 1.2-propanediol, LAB population, filamentous fungi, and pH value. No significant influence of the treatments with inoculants was observed in the variables DM, WSC, CP, lactic acid concentrations, or ethanol. The maximum temperature, i.e., the time to achieve the maximum temperature (TMT and aerobic stability (AS, was not influencied by treatments. However, a decrease in maximum temperature, an increase in TMT, and improvement in the AS were observed after 90 days of fermentation. These results proved the advantage of microbial inoculation. The treatments influenced LAB populations and filamentous fungi, but no effect was observed on the yeast population. The best inoculation dose is 6 cfu g-1 of forage because it provides higher reduction of filamentous fungi in maize silage, thereby decreasing the aerobic deterioration by these microorganisms.

Extractive fermentation of xylanase from Aspergillus tamarii URM 4634 in a bioreactor.

Science.gov (United States)

da Silva, Anna Carolina; Soares de França Queiroz, Alana Emília; Evaristo dos Santos Nascimento, Talita Camila; Rodrigues, Cristine; Gomes, José Erick Galindo; Souza-Motta, Cristina Maria; Porto de Souza Vandenberghe, Luciana; Valente de Medeiros, Erika; Moreira, Keila Aparecida; Herculano, Polyanna Nunes

2014-08-01

Of the many reported applications for xylanase, its use as a food supplement has played an important role for monogastric animals, because it can improve the utilisation of nutrients. The aim of this work was to produce xylanase by extractive fermentation in an aqueous two-phase system using Aspergillus tamarii URM 4634, increasing the scale of production in a bioreactor, partially characterising the xylanase and evaluating its influence on monogastric digestion in vitro. Through extractive fermentation in a bioreactor, xylanase was obtained with an activity of 331.4 U mL(-1) and 72% yield. The xylanase was stable under variable pH and temperature conditions, and it was optimally active at pH 3.6 and 90 °C. Xylanase activity potentiated the simulation of complete monogastric digestion by 6%, and only Mg2+ inhibited its activity. This process provides a system for efficient xylanase production by A. tamarii URM 4634 that has great potential for industrial use.

Feasibility of reusing the black liquor for enzymatic hydrolysis and ethanol fermentation.

Science.gov (United States)

Wang, Wen; Chen, Xiaoyan; Tan, Xuesong; Wang, Qiong; Liu, Yunyun; He, Minchao; Yu, Qiang; Qi, Wei; Luo, Yu; Zhuang, Xinshu; Yuan, Zhenhong

2017-03-01

The black liquor (BL) generated in the alkaline pretreatment process is usually thought as the environmental pollutant. This study found that the pure alkaline lignin hardly inhibited the enzymatic hydrolysis of cellulose (EHC), which led to the investigation on the feasibility of reusing BL as the buffer via pH adjustment for the subsequent enzymatic hydrolysis and fermentation. The pH value of BL was adjusted from 13.23 to 4.80 with acetic acid, and the alkaline lignin was partially precipitated. It deposited on the surface of cellulose and negatively influenced the EHC via blocking the access of cellulase to cellulose and adsorbing cellulase. The supernatant separated from the acidified BL scarcely affected the EHC, but inhibited the ethanol fermentation. The 4-times diluted supernatant and the last-time waste wash water of the alkali-treated sugarcane bagasse didn't inhibit the EHC and ethanol production. This work gives a clue of saving water for alkaline pretreatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of pH on retention of camel chymosin in curd

DEFF Research Database (Denmark)

Børsting, Mette Winther; Qvist, Karsten B.; Ardö, Ylva Margareta

2014-01-01

Retained coagulant in cheese initiates casein breakdown and influences cheese structure and flavour formation. This study investigated the influence of milk pH on retention of camel chymosin in curd and compared it with bovine chymosin. Milk at five different pH levels was coagulated with same...... coagulation activity. The retention of camel chymosin in curd was rather constant at ∼20% between pH 6.65 and 6.00, while it increased almost linear from 2 to 21% for bovine chymosin. The lower pH dependence for retention of camel chymosin than of bovine chymosin may be explained by a lower negative charge...

Physiochemical Properties and Antinutrient Content of Fermented ...

African Journals Online (AJOL)

Popcorn and groundnut composite flours were fermented using pure strains of Rhizopus nigricans and Saccharomyces cerevisiae by solid substrate fermentation method. There was decrease in pH with increase in total titrable acidity in all the samples. The result of the proximate analysis revealed that there was an ...

ENVIRONMENTAL AND PROCESS PARAMETERS OF METHANE FERMENTATION IN CONTINUOSLY STIRRED TANK REACTOR (CSTR

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Kamil Kozłowski

2016-12-01

Full Text Available A key indicator of methane fermentation process which influences the cost-effectiveness of the biogas plant is efficient production of methane per 1 m3 of reactor. It depends on the proper selection of environmental and process parameters. This article present collected and analyzed the effect of the most important parameters of continuous methane fermentation (CSTR, which include temperature, pH, nutrient content and the C/N ratio in the feed medium, the presence of inhibitors, and the volume load of reactor, retention time and mixing of digestion reactor. Still, the impact of many factors remain unknown, hence there is a need for more comprehensive studies.

Influence of pH on extracellular matrix preservation during lung decellularization.

Science.gov (United States)

Tsuchiya, Tomoshi; Balestrini, Jenna L; Mendez, Julio; Calle, Elizabeth A; Zhao, Liping; Niklason, Laura E

2014-12-01

The creation of decellularized organs for use in regenerative medicine requires the preservation of the organ extracellular matrix (ECM) as a means to provide critical cues for differentiation and migration of cells that are seeded onto the organ scaffold. The purpose of this study was to assess the influence of varying pH levels on the preservation of key ECM components during the decellularization of rat lungs. Herein, we show that the pH of the 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS)-based decellularization solution influences ECM retention, cell removal, and also the potential for host response upon implantation of acellular lung tissue. The preservation of ECM components, including elastin, fibronectin, and laminin, were better retained in the lower pH conditions that were tested (pH ranges tested: 8, 10, 12); glycosaminoglycans were preserved to a higher extent in the lower pH groups as well. The DNA content following decellularization of the rat lung was inversely correlated with the pH of the decellularization solution. Despite detectible levels of cyotoskeletal proteins and significant residual DNA, tissues decellularized at pH 8 demonstrated the greatest tissue architecture maintenance and the least induction of host response of all acellular conditions. These results highlight the effect of pH on the results obtained by organ decellularization and suggest that altering the pH of the solutions used for decellularization may influence the ability of cells to properly differentiate and home to appropriate locations within the scaffold, based on the preservation of key ECM components and implantation results.

Influence of fiber degradation and concentration of fermentable sugars on simultaneous saccharification and fermentation of high-solids spruce slurry to ethanol.

Science.gov (United States)

Hoyer, Kerstin; Galbe, Mats; Zacchi, Guido

2013-10-08

Saccharification and fermentation of pretreated lignocellulosic materials, such as spruce, should be performed at high solids contents in order to reduce the cost of the produced bioethanol. However, this has been shown to result in reduced ethanol yields or a complete lack of ethanol production. Previous studies have shown inconsistent results when prehydrolysis is performed at a higher temperature prior to the simultaneous saccharification and fermentation (SSF) of steam-pretreated lignocellulosic materials. In some cases, a significant increase in overall ethanol yield was reported, while in others, a slight decrease in ethanol yield was observed. In order to investigate the influence of prehydrolysis on high-solids SSF of steam-pretreated spruce slurry, in the present study, the presence of fibers and inhibitors, degree of fiber degradation and initial fermentable sugar concentration has been studied. SSF of whole steam-pretreated spruce slurry at a solids content of 13.7% water-insoluble solids (WIS) resulted in a very low overall ethanol yield, mostly due to poor fermentation. The yeast was, however, able to ferment the washed slurry and the liquid fraction of the pretreated slurry. Performing prehydrolysis at 48°C for 22 hours prior to SSF of the whole pretreated slurry increased the overall ethanol yield from 3.9 to 62.1%. The initial concentration of fermentable sugars in SSF could not explain the increase in ethanol yield in SSF with prehydrolysis. Although the viscosity of the material did not appear to decrease significantly during prehydrolysis, the degradation of the fibers prior to the addition of the yeast had a positive effect on ethanol yield when using whole steam-pretreated spruce slurry. The results of the present study suggest that the increase in ethanol yield from SSF when performing prehydrolysis is a result of fiber degradation rather than a decrease in viscosity. The increased concentration of fermentable sugars at the beginning of the

Vibration-induced particle formation during yogurt fermentation - Industrial vibration measurements and development of an experimental setup.

Science.gov (United States)

Körzendörfer, Adrian; Temme, Philipp; Nöbel, Stefan; Schlücker, Eberhard; Hinrichs, Jörg

2016-07-01

The aim of the study was to investigate the effects of vibrations during yogurt fermentation. Machinery such as pumps and switching valves generate vibrations that may disturb the gelation by inducing large particles. Oscillation measurements on an industrial yogurt production line showed that oscillations are transferred from pumps right up to the fermentation tanks. An experimental setup (20L) was developed to study the effect of vibrations systematically. The fermenters were decoupled with air springs to enable reference fermentations under idle conditions. A vibration exciter was used to stimulate the fermenters. Frequency sweeps (25-1005Hz, periodic time 10s) for 20min from pH5.4 induced large particles. The number of visible particles was significantly increased from 35±4 (reference) to 89±9 particles per 100g yogurt. Rheological parameters of the stirred yogurt samples were not influenced by vibrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effect of protected sardine fish oil as feed supplement on ruminal fermentation

Science.gov (United States)

Pramono, A.; Widayati, D. T.; Handayanta, E.

2018-03-01

The research aims to evaluate the influence of protected sardine fish oil as feed supplement on ruminal fermentation (pH rumen fluid, ammonia concentration and volatile fatty acids production in the rumen). Protected feed supplement was produced from sardine fish oil and soybean meal, through two protection methods, they were saponification and microencapsulation. The experiment consists of two treatments i.e. P0: basal diet (control) and P1: basal diet + 3 % protected feed supplement. Each treatment was repeated 10 times. The kinetics observation of the pH rumen fluid, ammonia concentration and volatile fatty acids production were performed at incubation times 0, 2, 4 and 6 hours respectively. Data were analyzed using independent samples t-test. Results in cow with protected feed supplement showed that kinetics of pH rumen fluid: 7.23; 7.13; 6.90 and 6.76 respectively; ruminal ammonia concentration: 26.70; 31.06; 19.75 and 15.52 respectively; and volatile fatty acids production: 22.75; 26.08; 29.19 and 25.79 respectively. The results could be concluded that the effect of supplementation of protected sardine fish oil have an optimal of pH rumen fluid, ammonia concentration, and volatile fatty acids production so it did not interfere the ruminal fermentation in the rumen.

EFFECT OF FERMENTED CACAO POD SUPPLEMENTATION ON SHEEP RUMEN MICROBIAL FERMENTATION

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S. Wulandari

2015-09-01

Full Text Available The objective of this research was to improve beneficial value of cacao pod as sheep feedingredients comprising up to 50% total feed. This research was conducted in two stages. Stage 1 wascacao pod fermentation. Completely randomized design with 3x3 factorial patterns was used in thisstage, in which factor I was microbial inoculum dosage of 0%, 0.05% and 0.1% and factor II wasincubation period of 0, 3 and 6 days. Result demonstrated that six-day fermentation with 0.05%microbial inoculum could lower cacao NDF, ADF and theobromine. The optimum inoculum dosage andfermentation time from stage 1 was applied to stage 2. Stage 2 was rumen microbial fermentation test.This research administrated 3x3 of latin square design. In period I sheep were fed with CF0 (nonfermentedcomplete feed, in period II sheep were given CF 1 (complete feed containing fermentedcacao pod and in period III sheep were given CF2 (fermented complete feed based cacao pod. Resultdemonstrated that pH value of sheep microbial liquid in treatment of CF0, CF1 and CF2 was in normalpH range and did not affect volatile fatty acids (VFA and ammonia. In conclusion, supplementing up to 50% of feed with complete feed containing fermented or non-fermented cacao pod did not affect theprocess of rumen microbial fermentation.

Effects of pH and Temperature on Recombinant Manganese Peroxidase Production and Stability

Science.gov (United States)

Jiang, Fei; Kongsaeree, Puapong; Schilke, Karl; Lajoie, Curtis; Kelly, Christine

The enzyme manganese peroxidase (MnP) is produced by numerous white-rot fungi to overcome biomass recalcitrance caused by lignin. MnP acts directly on lignin and increases access of the woody structure to synergistic wood-degrading enzymes such as cellulases and xylanases. Recombinant MnP (rMnP) can be produced in the yeast Pichia pastoris αMnP1-1 in fed-batch fermentations. The effects of pH and temperature on recombinant manganese peroxidase (rMnP) production by P. pastoris αMnP1-1 were investigated in shake flask and fed-batch fermentations. The optimum pH and temperature for a standardized fed-batch fermentation process for rMnP production in P. pastoris ctMnP1-1 were determined to be pH 6 and 30 °C, respectively. P. pastoris αMnP1-1 constitutively expresses the manganese peroxidase (mnp1) complementary DNA from Phanerochaete chrysosporium, and the rMnP has similar kinetic characteristics and pH activity and stability ranges as the wild-type MnP (wtMnP). Cultivation of P. chrysosporium mycelia in stationary flasks for production of heme peroxidases is commonly conducted at low pH (pH 4.2). However, shake flask and fed-batch fermentation experiments with P. pastoris αMnP1-1 demonstrated that rMnP production is highest at pH 6, with rMnP concentrations in the medium declining rapidly at pH less than 5.5, although cell growth rates were similar from pH 4-7. Investigations of the cause of low rMnP production at low pH were consistent with the hypothesis that intracellular proteases are released from dead and lysed yeast cells during the fermentation that are active against rMnP at pH less than 5.5.

On-line monitoring of CO2 production in Lactococcus lactis during physiological pH decrease using membrane inlet mass spectrometry with dynamic pH calibration.

Science.gov (United States)

Andersen, Ann Zahle; Lauritsen, Frants Roager; Olsen, Lars Folke

2005-12-20

Monitoring CO2 production in systems, where pH is changing with time is hampered by the chemical behavior and pH-dependent volatility of this compound. In this article, we present the first method where the concentration and production rate of dissolved CO2 can be monitored directly, continuously, and quantitatively under conditions where pH changes rapidly ( approximately 2 units in 15 min). The method corrects membrane inlet mass spectrometry (MIMS) measurements of CO2 for pH dependency using on-line pH analysis and an experimentally established calibration model. It is valid within the pH range of 3.5 to 7, despite pH-dependent calibration constants that vary in a non-linear fashion with more than a factor of 3 in this interval. The method made it possible to determine the carbon dioxide production during Lactococcus lactis fermentations, where pH drops up to 3 units during the fermentation. The accuracy was approximately 5%. We used the method to investigate the effect of initial extracellular pH on carbon dioxide production during anarobic glucose fermentation by non-growing Lactocoocus lactis and demonstrated that the carbon dioxide production rate increases considerably, when the initial pH was increased from 6 to 6.8. (c) 2005 Wiley Periodicals, Inc.

Evaluation of chemical changes during Myrciaria cauliflora (jabuticaba fruit) fermentation by {sup 1}H NMR spectroscopy and chemometric analyses

Energy Technology Data Exchange (ETDEWEB)

Fortes, Gilmara A.C.; Naves, Sara S.; Ferri, Pedro H.; Santos, Suzana C., E-mail: suzana.quimica.ufg@hotmail.com [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Inst. de Quimica. Lab. de Bioatividade Molecular

2012-10-15

Organic acids, sugars, alcohols, phenolic compounds, color properties, pH and titratable acidity were monitored during the commercial fermentation of jabuticaba (Myrciaria cauliflora) by {sup 1}H nuclear magnetic resonance (NMR) spectroscopy, spectrophotometric assays and standard methods of analysis. Data collected was analyzed by principal component (PCA), hierarchical cluster (HCA) and canonical correlation (CCA) analyses. Two sample groups were distinguished and the variables responsible for separation were sugars, anthocyanins, alcohols, hue and acetic and succinic acids. The canonical correlation analysis confirmed the influence of alcohols (ethanol, methanol and glycerol), organic acids (citric, succinic and acetic acids), pH and titratable acidity on the extraction and stability of anthocyanins and co pigments. As a result, color properties were also affected by phenolic variation throughout the fermentative process. (author)

Statistical optimization for tannase production from Aspergillus niger under submerged fermentation.

Science.gov (United States)

Sharma, S; Agarwal, L; Saxena, R K

2007-06-01

Statistically based experimental design was employed for the optimization of fermentation conditions for maximum production of enzyme tannase from Aspergillus niger. Central composite rotatable design (CCRD) falling under response surface methodology (RSM) was used. Based on the results of 'one-at-a-time' approach in submerged fermentation, the most influencing factors for tannase production from A. niger were concentrations of tannic acid and sodium nitrate, agitation rate and incubation period. Hence, to achieve the maximum yield of tannase, interaction of these factors was studied at optimum production pH of 5.0 by RSM. The optimum values of parameters obtained through RSM were 5% tannic acid, 0.8% sodium nitrate, 5.0 pH, 5 × 10(7) spores/50mL inoculum density, 150 rpm agitation and incubation period of 48 h which resulted in production of 19.7 UmL(-1) of the enzyme. This activity was almost double as compared to the amount obtained by 'one-at-a-time' approach (9.8 UmL(-1)).

Influence of culture medium pH on the production of CGTase by Bacillus firmus Strain No. 37 - doi: 10.4025/actascitechnol.v35i3.15882

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Jéssica Bravin Carmello

2013-06-01

Full Text Available The enzyme cyclomaltodextrin-glucanotransferase (CGTase is a transglicosidase able to convert corn starch into cyclodextrin (CD. CDs are widely applied in industry given the ability to form inclusion complexes with a great variety of organic molecules. Regarding the optimum pH of CGTase, values reported in the literature vary according to the enzyme producing microorganism, being 8.0 the optimum pH of CGTase produced by Bacillus firmus Strain No. 37. This work studied the influence of the pH of culture medium with different concentration of nutrients on the production of the enzyme CGTase by Bacillus firmus Strain No. 37. For this purpose, the microorganism was grown in three culture media with different concentrations of carbon and nitrogen. The pH control was performed by adding sodium carbonate. The fermentation process was analyzed by the following methods: Bradford (1976 method to determine soluble proteins, DNS method to analyze sugars, and the method of complexation with β-CD to analyze the enzyme activity. The best result for CGTase enzyme activity was 0.22 U mL-1, obtained with medium containing 2.0% soluble corn starch and yeast extract, and pH 8.3.  

Improved 1-Deoxynojirimycin (DNJ production in mulberry leaves fermented by microorganism

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Yun-Gang Jiang

2014-06-01

Full Text Available DNJ, an inhibitor of α-glucosidase, is used to suppress the elevation of postprandial hyperglycemia. In this study, we focus on screening an appropriate microorganism for performing fermentation to improve DNJ content in mulberry leaf. Results showed that Ganoderma lucidum was selected from 8 species and shown to be the most effective in improvement of DNJ production from mulberry leaves through fermentation. Based on single factor and three factor influence level tests by following the Plackett-Burman design, the optimum extraction yield was analyzed by response surface methodology (RSM. The extracted DNJ was determined by reverse-phase high performance liquid chromatograph equipped with fluorescence detector (HPLC-FD. The results of RSM showed that the optimal condition for mulberry fermentation was defined as pH 6.97, potassium nitrate content 0.81% and inoculums volume 2 mL. The extraction efficiency reached to 0.548% in maximum which is 2.74 fold of those in mulberry leaf.

Influence of gamma radiation on microbiological parameters of the ethanolic fermentation of sugar-cane must

International Nuclear Information System (INIS)

Alcarde, A.R.; Walder, J.M.M.; Horii, J.

2003-01-01

The influence of gamma radiation on reducing the population of some bacteria Bacillus and Lactobacillus that usually contaminate the sugar-cane must and its effects on acidity of the medium and viability of the yeast during fermentation were evaluated. The treatment with gamma radiation reduced the bacterial load of the sugar-cane must. Consequently, the volatile acidity produced during the fermentation of the must decreased and the viability of the yeast afterwards added increased

Ultrasonic Monitoring of the Progress of Lactic Acid Fermentation

Science.gov (United States)

Masuzawa, Nobuyoshi; Kimura, Akihiro; Ohdaira, Etsuzo

2003-05-01

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

Quality and Composition of Airén Wines Fermented by Sequential Inoculation of Lachancea thermotolerans and Saccharomyces cerevisiae

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Ángel Benito

2016-01-01

Full Text Available This study evaluates the influence of Lachancea thermotolerans on low-acidity Airén grape must from the south of Spain. For this purpose, combined fermentations with Lachancea thermotolerans and Saccharomyces cerevisiae were compared to a single fermentation by S. cerevisiae. Results of all developed analyses showed significant differences in several parameters including acidity, population growth kinetics, concentration of amino acids, volatile and non-volatile compounds, and sensorial parameters. The Airén wine quality increased mainly due to the acidification by L. thermotolerans. The acidification process caused a lactic acid increment of 3.18 g/L and a reduction of 0.22 in pH compared to the control fermentation, performed by S. cerevisiae.

Combined enzymatic hydrolysis and fermentation of hemicellulose to 2,3-butanediol

Energy Technology Data Exchange (ETDEWEB)

Yu, E.K.C.; Deschatelets, L.; Saddler, J.N.

1984-06-01

Hemicellulose-rich fractions from several agricultural residues were converted to 2,3-butanediol by a combined enzymatic hydrolysis and fermentation process. Culture filtrates from Trichoderma harzianum E58 were used to hydrolyze the substrates while Klebsiella pneumoniae fermented the liberated sugars to 2,3-butanediol. Approximately 50-60% of a 5% (w/v) xylan preparation could be hydrolyzed and quantitatively converted to 2,3-butanediol using this procedure. Although enzymatic hydrolysis was optimal at pH 5.0 and 50/sup 0/C, the combined hydrolysis and fermentation was most efficient at pH 6.5 and 30/sup 0/C. Combined hydrolysis and fermentation resulted in butanediol levels that were 20-40% higher than could be obtained with a separate hydrolysis and fermentation process. The hemicellulose-rich water-soluble fractions obtained from a variety of steam-exploded agricultural residues could be readily used by the combined hydrolysis and fermentation approach resulting in butanediol yields of 0.4-0.5 g/g of reducing sugar utilized.

The Effect of Cocoa Beans Fermentation on Processed Chocolate In West Kalimantan

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Jhon David H

2011-06-01

Full Text Available Research studies of fermentation effects on processed chocolate have been made. The purpose of this study was to see the effect of different levels of fermentation of cocoa preparations (pasta, fats and powder to the chemical quality and flavor. Harvested Cocoa beans will be treated fermentation. The treatment used was the time of fermentation namely: (A Non fermentation, (B Imperfect fermentation (4 days and (C Perfect fermentation (5 days. The parameters observed was: (a chemical quality namely water content, fat content, pH, (b organoleptic tests namely color, aroma, taste bitter (bitterness, texture. The results showed that fermentation of cocoa beans have real impact on levels of fat, water content and pH. Panelists gave the highest rankings for quality of organoleptic attributes of pasta, fat and chocolate powder from perfectly fermented beans. Processing of cocoa beans into refined products had levels of depreciation for each stage. 100 kg dried cocoa beans could produce 79.0 kilograms of chocolate paste, 48.7 kg of cocoa powder, and 26.5 kg of fat. Fermentation for 5 days is the best solution to improve the quality of processed chocolate.

The effect of cocoa fermentation and weak organic acids on growth and ochratoxin A production by Aspergillus species

DEFF Research Database (Denmark)

Copetti, Marina V.; Iamanaka, Beatriz T.; Mororó, Raimundo C.

2012-01-01

The acidic characteristics of cocoa beans have influence on flavor development in chocolate. Cocoa cotyledons are not naturally acidic, the acidity comes from organic acids produced by the fermentative microorganisms which grow during the processing of cocoa. Different concentrations of these met...... by Aspergillus carbonarius in cocoa, and the effect of weak organic acids such as acetic, lactic and citric at different pH values on growth and ochratoxin A production by A. carbonarius and Aspergillus niger in culture media. A statistical difference (ρ......The acidic characteristics of cocoa beans have influence on flavor development in chocolate. Cocoa cotyledons are not naturally acidic, the acidity comes from organic acids produced by the fermentative microorganisms which grow during the processing of cocoa. Different concentrations...... of these metabolites can be produced according to the fermentation practices adopted in the farms, which could affect the growth and ochratoxin A production by fungi. This work presents two independent experiments carried out to investigate the effect of some fermentation practices on ochratoxin A production...

Fermentation of lignocellulosic hydrolysates: Inhibition and detoxification

Energy Technology Data Exchange (ETDEWEB)

Palmqvist, E.

1998-02-01

The ethanol yield and productivity obtained during fermentation of lignocellulosic hydrolysates is decreased due to the presence of inhibiting compounds, such as weak acids, furans and phenolic compounds produced during hydrolysis. Evaluation of the effect of various biological, physical and chemical detoxification treatments by fermentation assays using Saccharomyces cerevisiae was used to characterise inhibitors. Inhibition of fermentation was decreased after removal of the non-volatile compounds, pre-fermentation by the filamentous fungus Trichoderma reesei, treatment with the lignolytic enzyme laccase, extraction with ether, and treatment with alkali. Yeast growth in lignocellulosic hydrolysates was inhibited below a certain fermentation pH, most likely due to high concentrations of undissociated weak acids. The effect of individual compounds were studied in model fermentations. Furfural is reduced to furfuryl alcohol by yeast dehydrogenases, thereby affecting the intracellular redox balance. As a result, acetaldehyde accumulated during furfural reduction, which most likely contributed to inhibition of growth. Acetic acid (10 g 1{sup -1}) and furfural (3 g 1{sup -1}) interacted antagonistically causing decreased specific growth rate, whereas no significant individual or interaction effects were detected by the lignin-derived compound 4-hydroxybenzoic acid (2 g 1{sup -1}). By maintaining a high cell mass density in the fermentor, the process was less sensitive to inhibitors affecting growth and to fluctuations in fermentation pH, and in addition the depletion rate of bioconvertible inhibitors was increased. A theoretical ethanol yield and high productivity was obtained in continuous fermentation of spruce hydrolysate when the cell mass concentration was maintained at a high level by applying cell recirculation 164 refs, 16 figs, 5 tabs

Influence of early pH decline on calpain activity in porcine muscle

DEFF Research Database (Denmark)

Pomponio, Luigi; Ertbjerg, Per; Karlsson, Anders H

2010-01-01

myofibril fragmentation at 24 h post-mortem was observed, which was no longer evident in the later phase of the tenderization process. In conclusion, the rate of early pH decline influenced l-calpain activity and the rate but not the extent of myofibrillar degradation, suggesting an early effect......This study investigated the influence of post-mortem pH decline on calpain activity and myofibrillar degradation.From 80 pigs, 30 Longissimus dorsi (LD) muscles were selected on the basis of pH values at 3 h post-mortem and classified into groups of 10 as fast, intermediate and slow pH decline...... measured. A faster decrease in pH resulted in reduced level of l-calpain activity and increased autolysis of the enzyme, and hence an earlier loss of activity due to activation of l-calpain in muscles with a fast pH decline. Paralleling the l-calpain activation in muscles with a fast pH decline a higher...

Comparison of the effect of benzoic acid addition on the fermentation process quality with untreated silages

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Petr Doležal

2004-01-01

Full Text Available The influence of benzoic acid and formic acid (positive control of ensilaged maize and pressed sugar beet pulp on quality fermentation processes was studied in a laboratory experiment. The effect of additive on the quality of fermentation process during maize ensiling was studied in a first model experiment. Preservatives such as formic acid and benzoic acid were added to ensiled maize at the concentration of 1L/t and 1 kg/t, respectively. When benzoic acid was used as a preservative, the pH and the N-NH3/ N total ratio decreased statistically (PSugar beet pulp silages with benzoic acid or formic acid after 32 days of storage had a better sensuous evaluation than the control silage. The most intensive decrease of pH value was observed after formic acid addition as compared with control silage. The statistically significantly (P<0.05 highest lactic acid content (49.64 ± 0.28 as well as the highest ratio of LA/VFA were found in the sugar beet pulp silage with benzoic acid. Lactic acid constituted the highest percentage (P<0.05 of all fermentation acids in the silage with benzoic acid additive (65.12 ± 0.80. Undesirable butyric acid (BA was not found in any variant of silages. The positive correlation between the titration acidity and acids sum in dry matter of silage conserved with formic acid was found. The additive of organic acids reduced significantly TA and fermentation acids content. Between the pH value and lactic acid content, no correlation was found.

Influence of initial pH on thermophilic anaerobic co-digestion of swine manure and maize stalk.

Science.gov (United States)

Zhang, Tong; Mao, Chunlan; Zhai, Ningning; Wang, Xiaojiao; Yang, Gaihe

2015-01-01

The contradictions between the increasing energy demand and decreasing fossil fuels are making the use of renewable energy the key to the sustainable development of energy in the future. Biogas, a renewable clean energy, can be obtained by the anaerobic fermentation of manure waste and agricultural straw. This study examined the initial pH value had obvious effect on methane production and the process in the thermophilic anaerobic co-digestion. Five different initial pH levels with three different manure ratios were tested. All digesters in different initial pH showed a diverse methane production after 35 days. The VFA/alkalinity ratio of the optimum reaction condition for methanogens activity was in the range of 0.1-0.3 and the optimal condition that at the 70% dung ratio and initial pH 6.81, was expected to achieve maximum total biogas production (146.32 mL/g VS). Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

Yogurt fermentation in the presence of starch-lipid composite.

Science.gov (United States)

Singh, M; Kim, S

2009-03-01

The fermentation of yogurt in the presence of 0.5%, 1.0%, 1.5%, and 2.0% starch-lipid composite (SLC) was investigated. The pH, viscosity, and morphology of the mix were monitored during the fermentation process. The rate of drop in pH with time during incubation was not affected by the addition of SLC. However, it was found that the presence of SLC caused faster aggregation, which was clearly evidenced by the viscosity variation during the process of fermentation. An examination of the morphologies confirmed that aggregation occurred earlier in the presence of SLC and SLC did not form phase-separated domains. This study concludes that SLC would serve as a good additive (fat replacer and stabilizer) for the production of yogurt.

Modeling the survival of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium during fermentation, drying, and storage of soudjouk-style fermented sausage.

Science.gov (United States)

Hwang, Cheng-An; Porto-Fett, Anna C S; Juneja, Vijay K; Ingham, Steven C; Ingham, Barbara H; Luchansky, John B

2009-02-28

This study quantified and modeled the survival of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella Typhimurium in soudjouk-style fermented sausage during fermentation, drying, and storage. Batter prepared from ground beef (20% fat), seasonings, starter culture, and dextrose was separately inoculated with a multi-strain mixture of each pathogen to an initial inoculum of ca. 6.5 log(10) CFU/g in the batter. The sausages were subsequently fermented at 24 degrees C with a relative humidity (RH) of 90% to 95% for 3 to 5 days to ca. pH 5.2, pH 4.9 or pH 4.6, then dried at 22 degrees C to a(w) 0.92, a(w) 0.89, or a(w) 0.86, respectively, and then stored at 4, 21, or 30 degrees C for up to 60 days. Lethality of the three pathogens was modeled as a function of pH, a(w) and/or storage temperature. During fermentation to pH 5.2 to pH 4.6, cell reductions ranged from 0 to 0.9 log(10) CFU/g for E. coli O157:H7, 0.1 to 0.5 log(10) CFU/g for L. monocytogenes, and 0 to 2.2 log(10) CFU/g for S. Typhimurium. Subsequent drying of sausages of pH 5.2 to pH 4.6 at 22 degrees C with 80% to 85% RH for 3 to 7 days to a(w) of 0.92 to a(w) 0.86 resulted in additional reductions that ranged from 0 to 3.5 log(10) CFU/g for E. coli O157:H7, 0 to 0.4 log(10) CFU/g for L. monocytogenes, and 0.3 to 2.4 log(10) CFU/g for S. Typhimurium. During storage at 4, 21, or 30 degrees C the reduction rates of the three pathogens were generally higher (pfermentation, drying, and storage. The applicability of the resulting models for fermented sausage was evaluated by comparing model predictions with published data. Pathogen reductions estimated by the models for E. coli O157:H7 and S. Typhimurium were comparable to 67% and 73% of published data, respectively. Due to limited published data for L. monocytogenes, the models for L. monocytogenes would need additional validations. Results of pathogen reductions from this study may be used as a reference to assist manufacturers of soudjouk

Lactose fermentation at Camembert, made by classic and stabilised

Directory of Open Access Journals (Sweden)

Bogdan Perko

2002-01-01

Full Text Available In our experiments the fermentation of lactose at Camembert type cheese by classic and stabilised technology was monitored. In each of the two technologies two experiments were made. The difference between these two technologies is in pH level, which drops below 5 by classic technology and remains above 5 by stabilised technology at all times. To achieve the criteria of stabilised technology the fermentation was stopped at a desired level of pH, by dropping the cheese in brine at 14 °C. After salting and moulding cheesewas transferred from the first three experiments into a ripening chamber at 11 °C. With the last experiment (stabilised technology the cheese ripened for 3 days at 5 °C. During ripening process pH dropped below 5 in all experiments. The process of fermentation was performed by the following lactic acid bacteria: Streptococcus thermophilus, Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris. As these lactic acid bacteria ferment differently D-galactose during manufacture and ripening process, the contentof lactose and D-galactose was measured. Based on the results of our research the following conclusion can be made: the action of lactic acid bacteria can not be stropped even at 5 °C. The native microflora, which remains in the milk after thermisation, might be responsible for the fermentation of Dgalactose. It could be possible that the Streptococcus thermophilus enzymes were not inactivated, causing continuation of lactose fermentation even at low temperature. Mesophilic lactococci were inhibited and for that reason Dgalactose accumulated in cheese. Only after cheese were transferred into a ripening chamber at 11 °C and with low lactose concentration in medium left, mesophilic lactococci started to ferment D-galactose.

Influence of pH on the localized corrosion of iron

International Nuclear Information System (INIS)

Webley, R.; Henry, R.

1986-06-01

The influence of pH on the pitting corrosion of iron in chloride and sulfate solutions was determined using two artificial pit apparatuses to obtain the pH near the surface of the pit bottom. A glass membrane electrode and an antimony electrode were used to measure pH in the two apparatuses. Using solutions of NaCl and Na 2 SO 4 at current densities of 0.5, 5.0, and 10 mA/cm 2 pH's in the range 5 to 6 were obtained with the first apparatus. The antimony probe did not measure pH accurately in solutions of 1 N NaCl and 1 N Na 2 SO 4 and had an error of approximately 2 pH units. A one-dimensional transport model was developed to predict pH variations around the pit mouth and inside the pit. The validity of this model was not verified due to the relative lack of precision with pH measurement techniques

Enhanced acarbose production by Streptomyces M37 using a two-stage fermentation strategy.

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Fei Ren

Full Text Available In this work, we investigated the effect of pH on Streptomyces M37 growth and its acarbose biosynthesis ability. We observed that low pH was beneficial for cell growth, whereas high pH favored acarbose synthesis. Moreover, addition of glucose and maltose to the fermentation medium after 72 h of cultivation promoted acarbose production. Based on these results, a two-stage fermentation strategy was developed to improve acarbose production. Accordingly, pH was kept at 7.0 during the first 72 h and switched to 8.0 after that. At the same time, glucose and maltose were fed to increase acarbose accumulation. With this strategy, we achieved an acarbose titer of 6210 mg/L, representing an 85.7% increase over traditional batch fermentation without pH control. Finally, we determined that the increased acarbose production was related to the high activity of glutamate dehydrogenase and glucose 6-phosphate dehydrogenase.

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.

The influence of narrow-leafed lupin seed fermentation on their chemical composition and ileal digestibility and microbiota in growing pigs.

Science.gov (United States)

Zaworska, Anita; Frankiewicz, Andrzej; Kasprowicz-Potocka, Małgorzata

2017-08-01

The aims of this study were to provide a controlled fermentation process of blue lupin seeds (Lupinus angustifolius, cv. Neptun), monitor the changes in seed composition and determine the influence of the fermentation on the apparent ileal digestibility (AID) of crude protein (CP) and amino acids in growing pigs, compared with raw lupin seeds. The fermentation with bacteria and yeast was conducted for 24 h at 25ºC under aerobic conditions. Seed fermentation increased the contents of CP, fibre, fat and ash and most of the analysed amino acids but reduced the levels of the nitrogen-free extractives. Furthermore, fermentation decreased the contents of raffinose family oligosaccharides and phytic acids but increased the alkaloid content. The AID was estimated on three barrows (mean initial body weight 25 kg), surgically fitted with a T-cannula in the distal ileum. The pigs received three diets, each for 6 d, within three experimental periods (3 × 3 Latin Square design). The diets contained soybean meal (Group SBM), raw lupin seeds (Group RL) or fermented lupin seeds (Group FL) as solely protein sources. Fermentation had a positive impact on the AID of CP and methionine, cysteine, isoleucine, leucine, phenylalanine and valine (p fermented lupin seeds did not affect the microbial status of the ileal digesta. Moreover, ammonia content in the caecal digesta did not differ between Groups RL and FL, although it was significantly higher than in Group SBM. It can be concluded that the fermentation process modified the chemical composition of nutrients in seeds, which can influence the digestibility and utilisation of the fermentation product in animal diets compared to raw seeds.

Mass transfer behavior in lactic acid fermentation using immobilized lactobacillus delbrueckii

Energy Technology Data Exchange (ETDEWEB)

Wang, H.; Seki, M.; Furusaki, S. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering

1995-08-20

We performed simulation studies on mass transfer behavior for immobilized cells in lactic acid fermentation using the mathematical model developed previously. The simulations pointed to an unusual result; that lactate ion diffuses into the bead center from outside during the batch fermentation and the startup period of the continuous fermentation, whereas free lactic acid and protons diffuse in the opposite direction. This phenomenon is caused by the addition of base to keep pH constant in the broth. Also, using an appropriate buffer to control pH in the broth can reduce the inward diffusion of lactate ion and improve the productivity of lactic acid. A singular mass transfer phenomenon is expected to take place in other production processes using immobilized cells (or enzyme), where alkali solution is added to broth to keep pH constant. 9 refs., 6 figs.

Utilization of Encapsulated CaCO_3 in Liquid Core Capsules for Improving Lactic Acid Fermentation

International Nuclear Information System (INIS)

Boon-Beng, Lee; Nurul Ainina Zulkifli

2016-01-01

Lactic acid bacteria (LAB) have been used for food fermentation due to its fermentative ability to improve and enhance the quality of the end food products. However, the performance of LAB is affected as fermentation time elapsed because the microbial growth is inhibited by its end product, for example lactic acid. In this study, a new approach was introduced to reduce the product inhibition effect using CaCO_3 which is encapsulated in spherical liquid core capsules of diameter 3.5 mm and 3.6 mm produced through extrusion dripping method. The results showed that the pH and lactic acid concentration of LAB fermentation was well maintained by the capsules. The results of the fermentation conducted to control pH and lactic acid concentration using the capsules were better than those of the control set and comparable with that of the free CaCO_3 set. In addition, the viable cell concentration of L. casei shirota was high at the end of fermentation when the fermentation was conducted using the capsules. The results of this study suggested that the capsules have high potential to be applied for pH and lactic acid level control in LAB fermentation for various productions. (author)

effective extraction of cephalosporin c from whole fermentation broth

African Journals Online (AJOL)

amina

2012-04-17

Apr 17, 2012 ... The effects of pH, neutral salts, temperature and centrifugal force on .... Fermentation was carried out in a defined media developed with slight modifications ... were pH 6.5, 200 rpm and incubation of culture for 72 h, as determined in our ... that CPC is rapidly inactivated at pH 12, while it is stable at pH 3.5.

Fermented Brown Rice Flour as Functional Food Ingredient

OpenAIRE

Ilowefah, Muna; Chinma, Chiemela; Bakar, Jamilah; Ghazali, Hasanah; Muhammad, Kharidah; Makeri, Mohammad

2014-01-01

As fermentation could reduce the negative effects of bran on final cereal products, the utilization of whole-cereal flour is recommended, such as brown rice flour as a functional food ingredient. Therefore, this study aimed to investigate the effect of fermented brown rice flour on white rice flour, white rice batter and its steamed bread qualities. Brown rice batter was fermented using commercial baker?s yeast (Eagle brand) according to the optimum conditions for moderate acidity (pH 5.5) to...

Changes in free-radical scavenging ability of kombucha tea during fermentation.

Science.gov (United States)

Jayabalan, R; Subathradevi, P; Marimuthu, S; Sathishkumar, M; Swaminathan, K

2008-07-01

Kombucha tea is a fermented tea beverage produced by fermenting sugared black tea with tea fungus (kombucha). Free-radical scavenging abilities of kombucha tea prepared from green tea (GTK), black tea (BTK) and tea waste material (TWK) along with pH, phenolic compounds and reducing power were investigated during fermentation period. Phenolic compounds, scavenging activity on DPPH radical, superoxide radical (xanthine-xanthine oxidase system) and inhibitory activity against hydroxyl radical mediated linoleic acid oxidation (ammonium thiocyanate assay) were increased during fermentation period, whereas pH, reducing power, hydroxyl radical scavenging ability (ascorbic acid-iron EDTA) and anti-lipid peroxidation ability (thiobarbituric assay) were decreased. From the present study, it is obvious that there might be some chances of structural modification of components in tea due to enzymes liberated by bacteria and yeast during kombucha fermentation which results in better scavenging performance on nitrogen and superoxide radicals, and poor scavenging performance on hydroxyl radicals. Copyright © 2007 Elsevier Ltd. All rights reserved.

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...

Fermentative conversion of swine and poultry wastes into nitrogen-enriched feedstuff for ruminants

Energy Technology Data Exchange (ETDEWEB)

Reddy, C A; Erdman, M D

1979-01-01

Swine and poultry wastes, augmented with carbohydrate-rich agroindustrial residues, were fermentatively converted into N-enriched feeds for ruminants. There was little increase in total N (TN) when unsupplemented swine waste filtrate (SWF) was fermented at pH 5.5, but considerable increase in TN was observed during fermentation of carbohydrate-supplemented SWF. The crude protein (CP) of the products ranged from 26-39%. Supplementation with cheese whey powder (CWP), potato starch, corn starch, or corn molasses gave 48, 33, 72, and 28% increases in TN respectively. Fermentation of CWP-supplemented SWF at pH 7.0 resulted in approximately 90% utilization of the added lactose within 8 hours and the product has a CP content of 47%. Fermentation of unsupplemented poultry waste filtrate (PWF) resulted in little increase in TN, while ammonia-N (AN) increased 5.5-fold and contributed 50% of the CP in the product obtained at the end of 8 hours of fermentation. In CWP-supplemented PWF fermentation 92% of the added whey lactose was metabolized, TN increased by 35%, and AN accounted for 63% of the TN. Thus, ammoniated fermentation of individual or mixed animal wastes, supplemented with a carbohydrate-rich agricultural residue can be conducted efficiently, batchwise, at pH 7.0 and 43 degrees, by indigenous microbial flora in the respective waste. The products obtained in each case are enriched in CP and organic acids.

PHYSIOLOGICAL REGULATION OF PROTEASE AND ANTIBIOTICS IN PENICILLIUM SP. USING SUBMERGED AND SOLID STATE FERMENTATION TECHNIQUES

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HAIDER M. HAMZAH

2009-03-01

Full Text Available A fungal strain belonging to the genus Penicillium was isolated from soil sample and has been diagnosed as Penicillium sp. according to its morphological characteristics of the colonies on solid media and also microscopical examination of the fungal parts. Antibiotics, protease activity and pH values were determined after cultivation of the fungus using submerged fermentation (SF and solid state fermentation (SSF. The two different patterns of fermentation processes seem to influence the physiological behavior of the fungus differently. Experiments were made using nutrient broth medium (N.B for SF and wheat bran in SSF. The pH values were adjacent to 5.5. Wheat bran was enriched with fish scales and egg shale in a ratio of (1:2:0.005 w/w and the mixture was moistened by adding (30 ml whey solution. After 7 days of incubation, the pH value of SF was increased to 8.0 at 30ºC. The SF was appeared efficient for antibiotics production. Using well diffusion technique the extracted antibiotics solution was active against some pathogenic bacteria such as Staphylococcus aureus, E. coli, Proteus sp., Salmonella sp., Pseudomonas aeruginosa and Streptococcus sp. In SSF relative proteases concentrations were found to be highly reactive than SF. This was proved by the appearance of the zone (20 mm and 32 mm due to the hydrolysis of milk and blood proteins respectively using pH 5.5 at 30ºC for 24 hrs. The activity of proteases was (10.4 U/ml.

Cow dung is an ideal fermentation medium for amylase production in solid-state fermentation by Bacillus cereus

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Ponnuswamy Vijayaraghavan

2015-12-01

Full Text Available Amylase production by Bacillus cereus IND4 was investigated by solid state fermentation (SSF using cow dung substrate. The SSF conditions were optimized by using one-variable-at-a-time approach and two level full factorial design. Two level full factorial design demonstrated that moisture, pH, fructose, yeast extract and ammonium sulphate have significantly influenced enzyme production (p < 0.05. A central composite design was employed to investigate the optimum concentration of these variables affecting amylase production. Maximal amylase production of 464 units/ml of enzyme was observed in the presence of 100% moisture, 0.1% fructose and 0.01% ammonium sulphate. The enzyme production increased three fold compared to the original medium. The optimum pH and temperature for the activity of amylase were found to be 8.0 and 50 °C, respectively. This enzyme was highly stable at wide pH range (7.0–9.0 and showed 32% enzyme activity after initial denaturation at 50 °C for 1 h. This is the first detailed report on the production of amylase by microorganisms using cow dung as the low cost medium.

Antagonistic effect of chosen lactic acid bacteria strains on Salmonella species in meat and fermented sausages.

Science.gov (United States)

Gomółka-Pawlicka, M; Uradziński, J

2003-01-01

The aim of this study was to determine of influence of 15 strains of lactic acid bacteria on the growth of 7 Salmonella spp. strains in model set-ups, and in meat and ripened fermented sausages. The investigations were performed within the framework of three alternate stages which differed in respect to the products studied, the number of Lactobacillus spp. strains and, partly, methodological approach. The ratio between lactic acid bacteria and Salmonella strains studied was, depending on the alternate, 1:1, 1:2 and 2:1, respectively. The investigations also covered the water activity (a(w)) and pH of the tested products. The results obtained are shown in 12 figures and suggest that all the lactic acid bacteria strains used within the framework of the model set-ups showed antagonistic effect on all the Salmonella spp. strains. However, these abilities were not observed with respect to some lactic acid bacteria strains in meat and fermented sausage. The temperature and length of the incubation period of sausages, but not a(w) and pH, were found to have a distinct influence on the antagonistic interaction between the bacteria.

Selection of lactic acid bacteria able to ferment inulin hydrolysates

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Octavian BASTON

2012-12-01

Full Text Available Eight homofermentative lactic acid bacteria isolates were tested for lactic acid production using chicory and Jerusalem artichoke hydrolysate as substrate. The pH, lactic acid yield and productivity were used to select the best homolactic bacteria for lactic acid production. The selected strains produced lactic acid at maximum yield after 24 hours of fermentation and the productivity was greater at 24 hours of fermentation. From all studied strains, Lb1 and Lb2 showed the best results regarding lactic acid yields andproductivity. After 48 hours of chicory and Jerusalem artichhoke hydrolysates fermentation, from all the studied strains, Lb2 produced the highest lactic acid yield (0.97%. Lb2 produced after 48 hours of fermentation the lowest pH value of 3.45±0.01. Lb2 showed greater lactic acid productivity compared to the other studied lactic acid bacteria, the highest values, 0.13 g·L-1·h-1fromJerusalem artichoke hydrolysate and 0.11g·L-1·h-1 from chicory hydrolysate, being produced after 24 hours of fermentation.

Antioxidant and Angiotensin-Converting Enzyme Inhibitory Activity of Eucalyptus camaldulensis and Litsea glaucescens Infusions Fermented with Kombucha Consortium.

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Gamboa-Gómez, Claudia I; González-Laredo, Rubén F; Gallegos-Infante, José Alberto; Pérez, Mş Del Mar Larrosa; Moreno-Jiménez, Martha R; Flores-Rueda, Ana G; Rocha-Guzmán, Nuria E

2016-09-01

Physicochemical properties, consumer acceptance, antioxidant and angiotensin-converting enzyme (ACE) inhibitory activities of infusions and fermented beverages of Eucalyptus camaldulensis and Litsea glaucescens were compared. Among physicochemical parameters, only the pH of fermented beverages decreased compared with the unfermented infusions. No relevant changes were reported in consumer preference between infusions and fermented beverages. Phenolic profile measured by UPLC MS/MS analysis demonstrated significant concentration changes of these compounds in plant infusions and fermented beverages. Fermentation induced a decrease in the concentration required to stabilize 50% of DPPH radical ( i . e . lower IC 50 ). Additionally, it enhanced the antioxidant activity measured by the nitric oxide scavenging assay (14% of E. camaldulensis and 49% of L. glaucescens ); whereas relevant improvements in the fermented beverage were not observed in the lipid oxidation assay compared with unfermented infusions. The same behaviour was observed in the inhibitory activity of ACE; however, both infusions and fermented beverages had lower IC 50 than positive control (captopril). The present study demonstrated that fermentation has an influence on the concentration of phenolics and their potential bioactivity. E. camaldulensis and L. glaucescens can be considered as natural sources of biocompounds with antihypertensive potential used either as infusions or fermented beverages.

Antioxidant and Angiotensin-Converting Enzyme Inhibitory Activity of Eucalyptus camaldulensis and Litsea glaucescens Infusions Fermented with Kombucha Consortium

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Claudia I. Gamboa-Gómez

2016-01-01

Full Text Available Physicochemical properties, consumer acceptance, antioxidant and angiotensin-converting enzyme (ACE inhibitory activities of infusions and fermented beverages of Eucalyptus camaldulensis and Litsea glaucescens were compared. Among physicochemical parameters, only the pH of fermented beverages decreased compared with the unfermented infusions. No relevant changes were reported in consumer preference between infusions and fermented beverages. Phenolic profi le measured by UPLC MS/MS analysis demonstrated significant concentration changes of these compounds in plant infusions and fermented beverages. Fermentation induced a decrease in the concentration required to stabilize 50 % of DPPH radical (i.e. lower IC50. Additionally, it enhanced the antioxidant activity measured by the nitric oxide scavenging assay (14 % of E. camaldulensis and 49 % of L. glaucescens; whereas relevant improvements in the fermented beverage were not observed in the lipid oxidation assay compared with unfermented infusions. The same behaviour was observed in the inhibitory activity of ACE; however, both infusions and fermented beverages had lower IC50 than positive control (captopril. The present study demonstrated that fermentation has an influence on the concentration of phenolics and their potential bioactivity. E. camaldulensis and L. glaucescens can be considered as natural sources of biocompounds with antihypertensive potential used either as infusions or fermented beverages.

A Novel simultaneous-Saccharification-Fermentation Strategy for Efficient Co-fermentation of C5 and C6 Sugars Using Native, Non-GMO Yeasts

Energy Technology Data Exchange (ETDEWEB)

Varanasi, Sasidhar [Univ. of Toledo, OH (United States); Relue, Patricia [Univ. of Toledo, OH (United States)

2013-09-30

Economic bioethanol production is critically dependent upon the ability to convert both the hexose (C6) and pentose (C5) sugars resulting from cellulose and hemicellulose. C5 sugars are not readily fermentable by native Saccharomyces cerevisiae. Genetically Modified Organisms (GMOs) are designed to ferment xylose, but their stability, ethanol yield, environmental impact, and survival under conditions of industrial fermentation are unproven. In this project, we developed a novel approach for efficient fermentation of both C5 and C6 sugars using native S. Cerevisiae by exploiting its ability to produce ethanol from xylulose - the keto-isomer of xylose. While the isomerization of xylose to xylulose can be accomplished via commercially (and cheaply) available Xylose Isomerase (XI) (Sweetzyme™), this conversion has an extremely unfavorable equilibrium (xylose:xylose is about 5:1). To address this, we developed two alternate strategies. In the first, the two enzymes XI and urease are coimmobilized on solid support particles to enable complete isomerization of xylose to xylulose under pH conditions suitable for fermentation, in a simultaneous-isomerization-fermentation (SIF) mode. The ability of our technology to conduct isomerization of xylose under pH conditions suitable for both saccharification and fermentation opens the possibility of SSF with native yeasts for the first time. Herein, we performed specific research tasks for implementation of our technology in several modes of operation, including simultaneous-isomerization-and-fermentation (SIF), simultaneous-saccharification-and-isomerization (SSI) followed by fermentation, and SSF mode with the biomass feedstock poplar. The projected economics of our process are very favorable in comparison to the costs associated with engineering, licensing and propagating GMOs. This novel fermentation technology is readily accessible to rural farming economies for implementation in cellulosic ethanol production facilities.

A novel inhibitor of Lactobacillus biofilms prevents stuck fermentations in a shake flask model

Science.gov (United States)

Yeast ethanol fermentations contain contaminating bacteria and yeast, with Lactobacilli being a frequent contaminant. These bacteria tolerate the low pH and high ethanol concentrations present in the fermentation, and can decrease the ethanol yield. Fermentations are routinely treated with antibioti...

ENDOSPORES OF THERMOPHILIC FERMENTATIVE BACTERIA

DEFF Research Database (Denmark)

Volpi, Marta

2016-01-01

solely based on endospores of sulphate-reducing bacteria (SRB), which presumably constitute only a small fraction of the total thermophilic endospore community reaching cold environments. My PhD project developed an experimental framework for using thermophilic fermentative endospores (TFEs) to trace...

Alkaline fermentation of waste sludge causes a significant reduction of antibiotic resistance genes in anaerobic reactors.

Science.gov (United States)

Huang, Haining; Zheng, Xiong; Chen, Yinguang; Liu, Hui; Wan, Rui; Su, Yinglong

2017-02-15

Alkaline fermentation has been reported to be an effective method to recover valuable products from waste sludge. However, to date, the potential effect of alkaline pH on the fate of antibiotic resistance genes (ARGs) during anaerobic fermentation of sludge has never been documented. In this study, the target ARGs in sludge was observed to be removed effectively and stably when sludge was anaerobically fermented at pH10. Compared with the control (without pH adjustment), the abundances of target ARGs at pH10 were reduced by 0.87 (sulI), 1.36 (sulII), 0.42 (tet(O)), 1.11 (tet(Q)), 0.79 (tet(C)) and 1.04 (tet(X)) log units. Further investigations revealed that alkaline fermentation shifted the community structures of potential ARGs hosts. Moreover, alkaline fermentation remarkably decreased the quantities and the ARGs-possessing ability of genetic vectors (plasmid DNA, extracellular DNA and phage DNA), which might limit the transfer of ARGs via conjugation, transformation and transduction. These results suggest that the shifted compositions of gene hosts and restricted gene transfer potential might be the critical reasons for the attenuation of ARGs at pH10. Copyright © 2016 Elsevier B.V. All rights reserved.

Lactic acid production from acidogenic fermentation of fruit and vegetable wastes.

Science.gov (United States)

Wu, Yuanyuan; Ma, Hailing; Zheng, Mingyue; Wang, Kaijun

2015-09-01

This work focused on the lactic acid production from acidogenic fermentation of fruit and vegetable wastes treatment. A long term completely stirred tank reactor (CSTR) lasting for 50 days was operated at organic loading rate (OLR) of 11 gVS/(L d) and sludge retention time (SRT) of 3 days with pH controlled at 4.0 (1-24 day) and 5.0 (25-50 day). The results indicated that high amount of approximately 10-20 g/L lactic acid was produced at pH of 4.0 and the fermentation type converted from coexistence of homofermentation and heterofermentation into heterofermentation. At pH of 5.0, the hydrolysis reaction was improved and the total concentration of fermentation products increased up to 29.5 g COD/L. The heterofermentation was maintained, however, bifidus pathway by Bifidobacterium played an important role. Copyright © 2015 Elsevier Ltd. All rights reserved.

Production of Pectate Lyase by Penicillium viridicatum RFC3 in Solid-State and Submerged Fermentation

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Viviani Ferreira

2010-01-01

Full Text Available Pectate lyase (PL was produced by the filamentous fungus Penicillium viridicatum RFC3 in solid-state cultures of a mixture of orange bagasse and wheat bran (1 : 1 w/w, or orange bagasse, wheat bran and sugarcane bagasse (1 : 1 : 0.5 w/w, and in a submerged liquid culture with orange bagasse and wheat bran (3% as the carbon source. PL production was highest (1,500 U  mL−1 or 300 Ug−1 of substrate in solid-state fermentation (SSF on wheat bran and orange bagasse at 96 hours. PL production in submerged fermentation (SmF was influenced by the initial pH of the medium. With the initial pH adjusted to 4.5, 5.0, and 5.5, the peak activity was observed after 72, 48, and 24 hours of fermentation, respectively, when the pH of the medium reached the value 5.0. PL from SSF and SmF were loaded on Sephadex-G75 columns and six activity peaks were obtained from crude enzyme from SSF and designated PL I, II, III, IV, V, and VI, while five peaks were obtained from crude enzyme from SmF and labeled PL  I′, II′, III′, IV′, and VII′. Crude enzyme and fraction III from each fermentative process were tested further. The optimum pH for crude PL from either process was 5.5, while that for PL III was 8.0. The maximum activity of enzymes from SSF was observed at 35∘C, but crude enzyme was more thermotolerant than PL III, maintaining its maximum activity up to 45∘C. Crude enzyme from SmF and PL   III′ showed thermophilic profiles of activity, with maximum activity at 60 and 55∘C, respectively. In the absence of substrate, the crude enzyme from SSF was stable over the pH range 3.0–10.0 and PL III was most stable in the pH range 4.0–7.0. Crude enzyme from SmF retained 70%–80% of its maximum activity in the acid-neutral pH range (4.0–7.0, but PIII showed high stability at alkaline pH (7.5–9.5. PL from SSF was more thermolabile than that from SmF. The latter maintained 60% of its initial activity after 1 h at 55�

Production of Pectate Lyase by Penicillium viridicatum RFC3 in Solid-State and Submerged Fermentation

Science.gov (United States)

Ferreira, Viviani; da Silva, Roberto; Silva, Dênis; Gomes, Eleni

2010-01-01

Pectate lyase (PL) was produced by the filamentous fungus Penicillium viridicatum RFC3 in solid-state cultures of a mixture of orange bagasse and wheat bran (1 : 1 w/w), or orange bagasse, wheat bran and sugarcane bagasse (1 : 1 : 0.5 w/w), and in a submerged liquid culture with orange bagasse and wheat bran (3%) as the carbon source. PL production was highest (1,500 U  mL−1 or 300 Ug−1 of substrate) in solid-state fermentation (SSF) on wheat bran and orange bagasse at 96 hours. PL production in submerged fermentation (SmF) was influenced by the initial pH of the medium. With the initial pH adjusted to 4.5, 5.0, and 5.5, the peak activity was observed after 72, 48, and 24 hours of fermentation, respectively, when the pH of the medium reached the value 5.0. PL from SSF and SmF were loaded on Sephadex-G75 columns and six activity peaks were obtained from crude enzyme from SSF and designated PL I, II, III, IV, V, and VI, while five peaks were obtained from crude enzyme from SmF and labeled PL  I′, II′, III′, IV′, and VII′. Crude enzyme and fraction III from each fermentative process were tested further. The optimum pH for crude PL from either process was 5.5, while that for PL III was 8.0. The maximum activity of enzymes from SSF was observed at 35°C, but crude enzyme was more thermotolerant than PL III, maintaining its maximum activity up to 45°C. Crude enzyme from SmF and PL III′ showed thermophilic profiles of activity, with maximum activity at 60 and 55°C, respectively. In the absence of substrate, the crude enzyme from SSF was stable over the pH range 3.0–10.0 and PL III was most stable in the pH range 4.0–7.0. Crude enzyme from SmF retained 70%–80% of its maximum activity in the acid-neutral pH range (4.0–7.0), but PIII showed high stability at alkaline pH (7.5–9.5). PL from SSF was more thermolabile than that from SmF. The latter maintained 60% of its initial activity after 1 h at 55°C. The differing

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

Science.gov (United States)

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

2009-04-01

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

Physico-chemical studies on amylases from fermented cassava waste water

International Nuclear Information System (INIS)

Oboh, G.; Akindahunsi, A.A.

2001-09-01

Waste water from cassava mash fermented with pure strain of Saccharomycees cerevisae together with Lactobacillus delbruckii and Lactobacillus coryneformis (3 days) was assayed for amylase activity. The result of the study indicated that the fermentation waste water had amylase activity, the unit activity and the specific activity of the amylase in the waste water was 0.22μmole/min and 0.06μmole/min/mg, respectively. The amylase was partially purified using Gel filtration (Sephadex-G150). The partially purified enzyme was maximally activity at pH 6.0 and 60 deg. C temperature. It had its maximum stability between pH 6-7 for 4hr, and 30 deg. C for 50 mins. NaCl, NH 4 Cl, FeCl 3 , KCl, NaNO 3 activates the enzyme activity while CUSO 4 and HgCl 2 inhibit the activity of the amylase. It could be concluded that these amylases from the fermented cassava waste amylase were active at wide temperature and pH ranges, this quality could be explored in the industrial sector (most especially food industry) as a source of industrial amylase that requires a wide range of conditions (temperature and pH). (author)

Effects of varying forage particle size and fermentable carbohydrates on feed sorting, ruminal fermentation, and milk and component yields of dairy cows.

Science.gov (United States)

Maulfair, D D; Heinrichs, A J

2013-05-01

Ration sorting is thought to affect ruminal fermentation in such a manner that milk yield milk and components are often decreased. However, the influence of ruminally degradable starch on ration sorting has not been studied. Therefore, the objective of this experiment was to evaluate the interactions between forage particle size (FPS) and ruminally fermentable carbohydrates (RFC) for dry matter intake (DMI), ration sorting, ruminal fermentation, chewing activity, and milk yield and components. In this study, 12 (8 ruminally cannulated) multiparous, lactating Holstein cows were fed a total mixed ration that varied in FPS and RFC. Two lengths of corn silage were used to alter FPS and 2 grind sizes of corn grain were used to alter RFC. It was determined that increasing RFC increased ruminating time and did not affect eating time, whereas increasing FPS increased eating time and did not affect ruminating time. Ruminal fermentation did not differ by altering either FPS or RFC. However, increasing FPS tended to increase mean and maximum ruminal pH and increasing RFC tended to decrease minimum ruminal pH. Particle size distribution became more diverse and neutral detergent fiber content of refusals increased over time, whereas starch content decreased, indicating that cows were sorting against physically effective neutral detergent fiber and for RFC. Selection indices determined that virtually no interactions occurred between FPS and RFC and that despite significant sorting throughout the day, by 24h after feeding cows had consumed a ration very similar to what was offered. This theory was reinforced by particle fraction intakes that very closely resembled the proportions of particle fractions in the offered total mixed ration. An interaction between FPS and RFC was observed for DMI, as DMI decreased with increasing FPS when the diet included low RFC and did not change when the diet included high RFC. Dry matter intake increased with RFC for long diets and did not change

Genotypic and phenotypic characterization of garlic-fermenting lactic acid bacteria isolated from som-fak, a Thai low-salt fermented fish product

DEFF Research Database (Denmark)

Paludan-Müller, Christine; Valyasevi, R.; Huss, Hans Henrik

2002-01-01

AIMS: To evaluate the importance of garlic for fermentation of a Thai fish product, and to differentiate among garlic-/inulin-fermenting lactic acid bacteria (LAB) at strain level. METHODS AND RESULTS: Som-fak was prepared by fermentation of a mixture of fish, salt, rice, sucrose and garlic. p......H decreased to 4.5 in 2 days, but omitting garlic resulted in a lack of acidification. LAB were predominant and approximately one third of 234 isolated strains fermented garlic and inulin (the carbohydrate reserve in garlic). These strains were identified as Lactobacillus pentosus and Lact. plantarum...... AND IMPACT OF THE STUDY: The present study indicates the role of fructans (garlic/inulin) as carbohydrate sources for LAB. Fructan fermenters may have several biotechnological applications, for example, as probiotics....

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

DEFF Research Database (Denmark)

Kemsawasd, Varongsiri; Monteiro Lomba Viana, Tiago; Ardö, Ylva

2015-01-01

-Saccharomyces yeast species (Lachancea thermotolerans, Metschnikowia pulcherrima, Hanseniaspora uvarum and Torulaspora delbrueckii) was investigated during alcoholic fermentation. Briefly, the N-sources with beneficial effects on all performance parameters (or for the majority of them) for each yeast species were...... for L. thermotolerans, H. uvarum and M. pulcherrima, single amino acids affected growth and fermentation performance to the same extent as the mixtures. Moreover, we found groups of N-sources with similar effects on the growth and/or fermentation performance of two or more yeast species. Finally...... species under oxygen-limited conditions, which, in turn, may be used to, e.g. optimize growth and fermentation performance of the given yeast upon N-source supplementation during wine fermentations....

Lactic acid fermentation of crude sorghum extract

Energy Technology Data Exchange (ETDEWEB)

Samuel, W.A.; Lee, Y.Y.; Anthony, W.B.

1980-04-01

Crude extract from sweet sorghum supplemented with vetch juice was utilized as the carbohydrate source for fermentative production of lactic acid. Fermentation of media containing 7% (w/v) total sugar was completed in 60-80 hours by Lactobacillus plantarum, product yield averaging 85%. Maximum acid production rates were dependent on pH, initial substrate distribution, and concentration, the rates varying from 2 to 5 g/liter per hour. Under limited medium supplementation the lactic acid yield was lowered to 67%. The fermented ammoniated product contained over eight times as much equivalent crude protein (N x 6.25) as the original medium. Unstructured kinetic models were developed for cell growth, lactic acid formation, and substrate consumption in batch fermentation. With the provision of experimentally determined kinetic parameters, the proposed models accurately described the fermentation process. 15 references.

Combined "de novo" and "ex novo" lipid fermentation in a mix-medium of corncob acid hydrolysate and soybean oil by Trichosporon dermatis.

Science.gov (United States)

Huang, Chao; Luo, Mu-Tan; Chen, Xue-Fang; Qi, Gao-Xiang; Xiong, Lian; Lin, Xiao-Qing; Wang, Can; Li, Hai-Long; Chen, Xin-De

2017-01-01

Microbial oil is one important bio-product for its important function in energy, chemical, and food industry. Finding suitable substrates is one key issue for its industrial application. Both hydrophilic and hydrophobic substrates can be utilized by oleaginous microorganisms with two different bio-pathways (" de novo " lipid fermentation and " ex novo " lipid fermentation). To date, most of the research on lipid fermentation has focused mainly on only one fermentation pathway and little work was carried out on both " de novo " and " ex novo " lipid fermentation simultaneously; thus, the advantages of both lipid fermentation cannot be fulfilled comprehensively. In this study, corncob acid hydrolysate with soybean oil was used as a mix-medium for combined " de novo " and " ex novo " lipid fermentation by oleaginous yeast Trichosporon dermatis . Both hydrophilic and hydrophobic substrates (sugars and soybean oil) in the medium can be utilized simultaneously and efficiently by T. dermatis . Different fermentation modes were compared and the batch mode was the most suitable for the combined fermentation. The influence of soybean oil concentration, inoculum size, and initial pH on the lipid fermentation was evaluated and 20 g/L soybean oil, 5% inoculum size, and initial pH 6.0 were suitable for this bioprocess. By this technology, the lipid composition of extracellular hydrophobic substrate (soybean oil) can be modified. Although adding emulsifier showed little beneficial effect on lipid production, it can modify the intracellular lipid composition of T. dermatis . The present study proves the potential and possibility of combined " de novo " and " ex novo " lipid fermentation. This technology can use hydrophilic and hydrophobic sustainable bio-resources to generate lipid feedstock for the production of biodiesel or other lipid-based chemical compounds and to treat some special wastes such as oil-containing wastewater.

Microbial Production of Xylitol from Oil Palm Empty Fruit Bunch Hydrolysate: Effects of Inoculum and pH

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M.T.A.P. Kresnowati

2016-11-01

Full Text Available Considering its high content of hemicellulose, oil palm empty fruit bunch (EFB lignocellulosic biomass waste from palm oil processing has the potential to be utilized as the raw material for the production of xylitol, a low calorie, low GI, and anti cariogenic alternative sugar with similar sweetness to sucrose. This research explored the possibility of converting EFB to xylitol via green microbial fermentation, in particular the effects of inoculum and initial pH on the fermentation performance. It was observed that the cell concentration in the inoculum and the initial pH affect cell growth and xylitol production. pH 5 was observed to give the best fermentation performance. Further, the fermentation tended to yield more xylitol at higher initial cell concentration. It was also observed that no growth or fermentation inhibitory compounds were found in the EFB hydrolysate obtained from enzymatic hydrolysis of EFB. Thus it can be used directly as substrate for xylitol fermentation.

Microbiological profiles, pH, and titratable acidity of chorizo and salchichón (two Spanish dry fermented sausages) manufactured with ostrich, deer, or pork meat.

Science.gov (United States)

Capita, Rosa; Llorente-Marigómez, Sandra; Prieto, Miguel; Alonso-Calleja, Carlos

2006-05-01

Microbial counts, pH, and titratable acidity were determined in 102 Spanish dry fermented sausages (chorizo and salchichón) made with ostrich, deer, or pork meat. Average microbial counts (log CFU per gram) varied from 5.46 +/- 0.24 to 8.25 +/- 0.80 (total viable counts), from 4.79 +/- 0.36 to 7.99 +/- 0.20 (psychrotrophs), from 0.00 +/- 0.00 to 0.99 +/- 1.10 (undetectable values were assumed to be zero) (Enterobacteriaceae), from 0.00 +/- 0.00 to 4.27 +/- 1.47 (enterococci), from 5.15 +/- 1.15 to 8.46 +/- 0.49 (lactic acid bacteria), from 3.08 +/- 0.44 to 6.59 +/- 1.76 (Micrococcaceae), from 2.27 +/- 1.53 to 5.11 +/- 1.81 (molds and yeasts), from 0.00 +/- 0.00 to 2.25 +/- 0.81 (pseudomonads), and from 0.00 +/- 0.00 to 2.78 +/- 0.46 (Brochothrix thermosphacta). Average pH and titratable acidity varied from 5.07 +/- 0.25 to 5.63 +/- 0.51 (pH units) and from 0.30 +/- 0.01 to 0.86 +/- 0.19 (% lactic acid). Both type of sausage (P < 0.05) and species of meat (P < 0.001) influenced microbial counts. Salchich6n samples showed lower average values than chorizo samples for most microbial groups (significant for Enterobacteriaceae, lactic acid bacteria, and B. thermosphacta) and titratable acidity. Sausages made from pork showed the highest microbial loads for total viable counts, psychrotrophs, Enterobacteriaceae, enterococci, lactic acid bacteria, and yeasts and molds. Higher counts were observed only for pseudomonads in ostrich sausages. B. thermosphacta levels were similar for all species of meat. The highest average pH value was observed in sausages made from ostrich meat, and the lowest titratable acidity level was found in pork sausages.

Batch pervaporative fermentation with coupled membrane and its influence on energy consumption in permeate recovery and distillation stage

International Nuclear Information System (INIS)

Leon, Juan A.; Palacios-Bereche, Reynaldo; Nebra, Silvia A.

2016-01-01

In the ethanol production process from sugarcane molasses, the distillation process is a high-energy demand stage. The distillation energy efficiency is strongly associated with the alcoholic fermentation performance in the process. The final ethanol concentration in the alcoholic wines has a direct impact on consumption of thermal energy in ethanol separation. In this paper, ethanol production with a H-SBMF (Hybrid-Simple Batch Membrane Fermenter) using PDMS (polydimethylsiloxane) pervaporation membrane was modelled and simulated, in order to determine its influence on energy consumption in distillation. Steam in distillation and electrical energy needs in permeate recovery were mainly influenced by membrane adaptation. The H-SBMF achieved a higher ethanol production in the range of 10–13% compared to the conventional batch fermenter, and an increase in productivity of 150%. The distillation system consisted of two sets of columns: the ethanol recovery column and the rectification column. The permeate recovery system (i.e. vacuum and compression) was regarded in order to evaluate the electrical energy requirement, and the thermal energy demand was evaluated. A decrease in steam consumption was evidenced by the adaptation of the membrane to the fermenter. Higher energy efficiencies were achieved in distillation with larger membrane areas, achieving almost 17% steam reduction. - Highlights: • Higher and faster ethanol productions were achieved by fermenter hybridization. • Multi-stage permeate compression and inter-stage heat recovery were assumed. • Energy demand was studied based on an integrated fermentation and distillation scheme. • High-energy efficiency was attained in the distillation to produce hydrated alcohol.

Titratable acidity of beverages influences salivary pH recovery.

Science.gov (United States)

Tenuta, Livia Maria Andaló; Fernández, Constanza Estefany; Brandão, Ana Carolina Siqueira; Cury, Jaime Aparecido

2015-01-01

A low pH and a high titratable acidity of juices and cola-based beverages are relevant factors that contribute to dental erosion, but the relative importance of these properties to maintain salivary pH at demineralizing levels for long periods of time after drinking is unknown. In this crossover study conducted in vivo, orange juice, a cola-based soft drink, and a 10% sucrose solution (negative control) were tested. These drinks differ in terms of their pH (3.5 ± 0.04, 2.5 ± 0.05, and 5.9 ± 0.1, respectively) and titratable acidity (3.17 ± 0.06, 0.57 ± 0.04 and pH 5.5, respectively). Eight volunteers with a normal salivary flow rate and buffering capacity kept 15 mL of each beverage in their mouth for 10 s, expectorated it, and their saliva was collected after 15, 30, 45, 60, 90, and 120 s. The salivary pH, determined using a mini pH electrode, returned to the baseline value at 30 s after expectoration of the cola-based soft drink, but only at 90 s after expectoration of the orange juice. The salivary pH increased to greater than 5.5 at 15 s after expectoration of the cola drink and at 30 s after expectoration of the orange juice. These findings suggest that the titratable acidity of a beverage influences salivary pH values after drinking acidic beverages more than the beverage pH.

Use of milk-based kombucha inoculum for milk fermentation

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Kolarov Ljiljana A.

2009-01-01

Full Text Available In this investigation fermented milk beverages with 0.9% of milk fat were produced using 10 and 15% (v/v of traditional and milk-based kombucha inoculum by application of appropriate technological process. Milk fermentation using two types and concentrations of kombucha inoculum were stopped when the pH reached 4.5. Sigmoidal fermentation profiles were noticed with traditional kombucha inoculums and linear with milk-based kombucha inoculums. Chemical content and physico-chemical characteristics of kombucha fermented milk beverages were typical and yoghurt-like for all obtained products. The best textural and sensory characteristics possesed beverage obtained in fermentation of milk using 10% (v/v of milk-based kombucha inoculum.

Effect of pH on sludge composting

International Nuclear Information System (INIS)

Hashimoto, Shoji; Watanabe, Hiromasa; Nishimura, Koichi; Kawakami, Waichiro

1984-01-01

The effect of pH on composting of irradiated sewage sludge was discussed. Inorganic materials, such as activated alumina, Kanuma-soil, and Akadama-soil, were used as bulking agents. Na 2 CO 3 was used as a pH adjuster. The fermentations were done isothermally at the optimum temperature, 50 0 C. The rate of CO 2 evolution increased initially with time, and then, decreased. The peak value of CO 2 evolution and the time to attain the peak varied by the addition of Na 2 CO 3 . When Kanuma-soil was used as the bulking agent, for example, the peak value became larger as the amount of Na 2 CO 3 was increased to 1.0 % and became smaller over this value. From pH measurements, it was found that the optimum pH for fermentation was ranged from 6 to 8 when activated alumina was used. When other bulking agents were used, the maximum value of CO 2 evolution rate was obtained at pH 7 to 8.5. The peak value and the peak time also varied by the addition of NH 3 in the aeration gas. (author)

Study on the Effect of cellulolytic strain MYB3 for Corn Stover Fermentation

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Yan, Han; Bai, Bing; Cheng, Xiao-Xiao; Li, Guang-Chun; Huang, Shi-Chen; Piao, Chun-Xiang

2018-03-01

The effects of corn stover fermentation with the Bacillus megaterium MYB3 was studied in this paper. The results showed that the decomposition rates of cellulose and hemicellulose were 49.6%, 43.46% after 20 days respectively, after fermentation, pH was changed to 5.68, and adjusted to corn stover initial pH 3 to achieve the purpose of sterilization. The decomposition rate was significantly increased by adding corn flour. After adjusting fermentation composes with the ratio of the corn stove to corn flour was 15 : 1, the decomposition rate of cellulose would be 52.37% for 10 days.

Recovery of carboxylic acids produced during dark fermentation of food waste by adsorption on Amberlite IRA-67 and activated carbon.

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Yousuf, Ahasa; Bonk, Fabian; Bastidas-Oyanedel, Juan-Rodrigo; Schmidt, Jens Ejbye

2016-10-01

Amberlite IRA-67 and activated carbon were tested as promising candidates for carboxylic acid recovery by adsorption. Dark fermentation was performed without pH control and without addition of external inoculum at 37°C in batch mode. Lactic, acetic and butyric acids, were obtained, after 7days of fermentation. The maximum acid removal, 74%, from the Amberlite IRA-67 and 63% from activated carbon was obtained from clarified fermentation broth using 200gadsorbent/Lbroth at pH 3.3. The pH has significant effect and pH below the carboxylic acids pKa showed to be beneficial for both the adsorbents. The un-controlled pH fermentation creates acidic environment, aiding in adsorption by eliminating use of chemicals for efficient removal. This study proposes simple and easy valorization of waste to valuable chemicals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microbial ecology of sourdough fermentations: diverse or uniform?

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De Vuyst, L; Van Kerrebroeck, S; Harth, H; Huys, G; Daniel, H-M; Weckx, S

2014-02-01

Sourdough is a specific and stressful ecosystem inhabited by yeasts and lactic acid bacteria (LAB), mainly heterofermentative lactobacilli. On the basis of their inocula, three types of sourdough fermentation processes can be distinguished, namely backslopped ones, those initiated with starter cultures, and those initiated with a starter culture followed by backslopping. Typical sourdough LAB species are Lactobacillus fermentum, Lactobacillus paralimentarius, Lactobacillus plantarum, and Lactobacillus sanfranciscensis. Typical sourdough yeast species are Candida humilis, Kazachstania exigua, and Saccharomyces cerevisiae. Whereas region specificity is claimed in the case of artisan backslopped sourdoughs, no clear-cut relationship between a typical sourdough and its associated microbiota can be found, as this is dependent on the sampling, isolation, and identification procedures. Both simple and very complex consortia may occur. Moreover, a series of intrinsic and extrinsic factors may influence the composition of the sourdough microbiota. For instance, an influence of the flour (type, quality status, etc.) and the process parameters (temperature, pH, dough yield, backslopping practices, etc.) occurs. In this way, the presence of Lb. sanfranciscensis during sourdough fermentation depends on specific environmental and technological factors. Also, Triticum durum seems to select for obligately heterofermentative LAB species. Finally, there are indications that the sourdough LAB are of intestinal origin. Copyright © 2013 Elsevier Ltd. All rights reserved.

Influence of yeast and lactic acid bacterium on the constituent profile of soy sauce during fermentation.

Science.gov (United States)

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

2017-02-01

Soy sauce is a Japanese traditional seasoning composed of various constituents that are produced by various microbes during a long-term fermentation process. Due to the complexity of the process, the investigation of the constituent profile during fermentation is difficult. Metabolomics, the comprehensive study of low molecular weight compounds in biological samples, is thought to be a promising strategy for deep understanding of the constituent contribution to food flavor characteristics. Therefore, metabolomics is suitable for the analysis of soy sauce fermentation. Unfortunately, only few and unrefined studies of soy sauce fermentation using metabolomics approach have been reported. Therefore, we investigated changes in low molecular weight hydrophilic and volatile compounds of soy sauce using gas chromatography/mass spectrometry (GC/MS)-based non-targeted metabolic profiling. The data were analyzed by statistical analysis to evaluate influences of yeast and lactic acid bacterium on the constituent profile. Consequently, our results suggested a novel finding that lactic acid bacterium affected the production of several constituents such as cyclotene, furfural, furfuryl alcohol and methional in the soy sauce fermentation process. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Development of an In Vivo and In Vitro Ileal Fermentation Method in a Growing Pig Model.

Science.gov (United States)

Montoya, Carlos A; de Haas, Edward S; Moughan, Paul J

2018-02-01

Substantial microbial fermentation may occur mainly in the lower small intestine (SI) of human adults, but there is no established methodology to determine this. The study aimed to develop a combined in vivo and in vitro methodology for ileal fermentation based on the pig as an animal model for digestion in human adults. Several aspects of a combined in vivo/in vitro ileal fermentation assay were evaluated. Male 9-wk-old pigs (n = 30; mean ± SD body weight: 23 ± 1.6 kg) were fed a human-type diet (143, 508, 45, 49, and 116 g/kg dry matter diet of crude protein, starch, total lipid, ash, and total dietary fiber) for 15 d. On day 15, pigs were killed, and the last third of the SI was collected to prepare an ileal digesta-based inoculum. Terminal jejunal digesta (last 50 cm of the second third of the SI) were collected as substrate for the assay to test the form of substrate (fresh or freeze-dried), origin (location in jejunum or SI) of the substrate, storage of the inoculum, incubation time (1.2-6.8 h), pH of the medium, and inoculum concentration (6-26 mg inoculum/100 mg substrate). The group of donor pigs used to prepare the inoculum, form of the substrate, origin of the substrate, origin of the inoculum (location in the SI), storage of the inoculum, incubation time, and inoculum concentration did not influence the in vitro ileal organic matter (OM) fermentability (P > 0.05). The in vitro ileal OM fermentability decreased when the pH of the medium increased from 5.5 to 7.5 (31% to 28%; P ≤ 0.05). Predicted (in vivo/in vitro) apparent ileal OM digestibility was similar to the value measured in vivo. Thirty-percent of the terminal jejunal digesta OM was fermented in the ileum. Fiber fermentation in the ileum can be studied using the optimized in vivo/in vitro ileal fermentation method.

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.

Influence of cultivating conditions on the alpha-galactosidase biosynthesis from a novel strain of Penicillium sp. in solid-state fermentation.

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Wang, C L; Li, D F; Lu, W Q; Wang, Y H; Lai, C H

2004-01-01

The work is intended to achieve optimum culture conditions of alpha-galactosidase production by a mutant strain Penicillium sp. in solid-state fermentation (SSF). Certain fermentation parameters involving incubation temperature, moisture content, initial pH value, inoculum and load size of medium, and incubation time were investigated separately. The optimal temperature and moisture level for alpha-galactosidase biosynthesis was found to be 30 degrees C and 50%, respectively. The range of pH 5.5-6.5 was favourable. About 40-50 g of medium in 250-ml flask and inoculum over 1.0 x 10(6) spores were suitable for enzyme production. Seventy-five hours of incubation was enough for maximum alpha-galactosidase production. Substrate as wheat bran supplemented with soyabean meal and beet pulp markedly improved the enzyme yield in trays. Under optimum culture conditions, the alpha-galactosidase activity from Penicillium sp. MAFIC-6 indicated 185.2 U g(-1) in tray of SSF. The process on alpha-galactosidase production in laboratory scale may have a potentiality of scaling-up.

Submerged fermentation of Lactobacillus rhamnosus YS9 for γ-aminobutyric acid (GABA) production

OpenAIRE

Lin,Qian

2013-01-01

γ-Aminobutyric acid (GABA) is a major inhibitory neurotransmitter in central nervous system, and its application in drugs and functional foods has attracted great attention. To enhance production of y-aminobutyric acid, Lactobacillus rhamnosus YS9, a strain isolated from Chinese traditional fermented food pickled vegetable, was grown under submerged fermentation. Its cultivation conditions were investigated. When culture pH condition was adjusted to the optimal pH of glutamate decarboxyl...

Biogasification of solid wastes by two-phase anaerobic fermentation

International Nuclear Information System (INIS)

Ghosh, S.; Vieitez, E.R.; Liu, T.; Kato, Y.

1997-01-01

Municipal, industrial and agricultural solid wastes, and biomass deposits, cause large-scale pollution of land and water. Gaseous products of waste decomposition pollute the air and contribute to global warming. This paper describes the development of a two-phase fermentation system that alleviates methanogenic inhibition encountered with high-solids feed, accelerates methane fermentation of the solid bed, and captures methane (renewable energy) for captive use to reduce global warming. The innovative system consisted of a solid bed reactor packed with simulated solid waste at a density of 160 kg/m 3 and operated with recirculation of the percolated culture (bioleachate) through the bed. A rapid onset of solids hydrolysis, acidification, denitrification and hydrogen gas formation was observed under these operating conditions. However, these fermentative reactions stopped at a total fatty acids concentration of 13,000 mg/l (as acetic) at pH 5, with a reactor head-gas composition of 75 percent carbon dioxide, 20 percent nitrogen, 2 percent hydrogen and 3 percent methane. Fermentation inhibition was alleviated by moving the bioleachate to a separate methane-phase fermenter, and recycling methanogenic effluents at pH 7 to the solid bed. Coupled operation of the two reactors promoted methanogenic conversion of the high-solids feed. (author)

Titratable acidity of beverages influences salivary pH recovery

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Livia Maria Andaló TENUTA

2015-01-01

Full Text Available A low pH and a high titratable acidity of juices and cola-based beverages are relevant factors that contribute to dental erosion, but the relative importance of these properties to maintain salivary pH at demineralizing levels for long periods of time after drinking is unknown. In this crossover study conducted in vivo, orange juice, a cola-based soft drink, and a 10% sucrose solution (negative control were tested. These drinks differ in terms of their pH (3.5 ± 0.04, 2.5 ± 0.05, and 5.9 ± 0.1, respectively and titratable acidity (3.17 ± 0.06, 0.57 ± 0.04 and < 0.005 mmols OH- to reach pH 5.5, respectively. Eight volunteers with a normal salivary flow rate and buffering capacity kept 15 mL of each beverage in their mouth for 10 s, expectorated it, and their saliva was collected after 15, 30, 45, 60, 90, and 120 s. The salivary pH, determined using a mini pH electrode, returned to the baseline value at 30 s after expectoration of the cola-based soft drink, but only at 90 s after expectoration of the orange juice. The salivary pH increased to greater than 5.5 at 15 s after expectoration of the cola drink and at 30 s after expectoration of the orange juice. These findings suggest that the titratable acidity of a beverage influences salivary pH values after drinking acidic beverages more than the beverage pH.

Utilization of cassava waste through fermentation technology

International Nuclear Information System (INIS)

Lotong, N.

1991-01-01

Over 400 isolates of molds were screened for raw starch digesting enzymes and aspergillus J8 ad Rhizopus N37 were selected for further investigations. Crude enzymes obtained from wheat bran was higher than from rice bran. Crude enzymes from Aspergillus is active at pH 4.0, whereas that from Rhizopus is active at pH 5.0. Aspergillus J8 gave higher yield of silage fermentation. Selection of yeast strain was accomplished, it was found that Saccharomyces cerevisiae SC90, the local commercial strain (non-flocculent) performed best in fermentation of cassava mash. Another strain AM12, a flocculent fusant strain derived from fusion between flocculent strain and sake brewing strain was comparable to that of commercial strain at normal temperature but performed better at higher temperature up to 40 deg C. It is unlikely that fuel alcohol produced from raw cassava will be able to compete with petroleum fuel at this moment. However, silage fermentation to increase nutritional quality of the silage through selected strains of microorganisms has a good prospect to pursue. (author)

Influence of yogurt fermentation and refrigerated storage on the stability of protein toxin contaminants.

Science.gov (United States)

Jackson, Lauren S; Triplett, Odbert A; Tolleson, William H

2015-06-01

Dairy products sold in a ready-to-eat form present the risk that adulterants persisting through manufacturing, storage, and distribution would reach consumers. Pathogenic microbes, including shigatoxigenic strains of Escherichia coli and the toxins they produce, are common food safety hazards associated with dairy products. Ricin and abrin are plant-derived ribosome-inactivating protein toxins related to the shiga-like toxins produced by E. coli. Limited information exists on the effects of manufacturing processes on the stabilities of these heat-resistant ribosome-inactivating proteins in the presence of foods. The goal of this study was to determine how typical yogurt manufacturing and storage processes influence ribosome-inactivating protein toxins. Ricin and abrin were added to skim or whole milk and batch pasteurized. Complete inactivation of both toxins was observed after 30 minutes at 85 °C. If the toxins were added after pasteurization, the levels of ricin and abrin in yogurt and their cytotoxic activities did not change significantly during fermentation or refrigerated storage for 4 weeks. The activities of ricin and abrin were inhibited by skim milk, nonfat yogurt, whole milk, and whole milk yogurt. The results showed minimal effects of the toxins on yogurt pH and %titratable acidity but inhibitory effects of yogurt on toxin activity. Published by Elsevier Ltd.

Effects of methanogenic effluent recycle on fermentative hydrogen production

Energy Technology Data Exchange (ETDEWEB)

Kraemer, J.T.; Bagley, D.M. [Toronto Univ., ON (Canada). Dept. of Civil Engineering

2004-07-01

Most research on fermentative hydrogen production has focused on optimizing the process and not on the practicalities of pH control although active pH control in a hydrogen reactor is necessary for stable and efficient performance. Batch experiments have shown that hydrogen ceases to be produced when there is no pH control. This study determined if recycle effluent from the methane reactor of a two-phase hydrogen-producing system would reduce the external alkali needed for pH control in a hydrogen reactor. It also determined if recycle affected the performance of the hydrogen reactor and the overall two-phase system. This paper describes the experimental laboratory-scale, two-phase hydrogen producing system which was operated alternately with and without effluent recycle from a methane reactor to the hydrogen reactor. The two-phase hydrogen producing system yielded 5.7 times more energy recovery than that obtained by the fermentative hydrogen producing reactor alone. The use of effluent from the methane reactor can reduce the operational cost of external alkali for pH control. 6 refs., 5 figs.

Fermentation characteristics and transit tolerance of probiotic Lactobacillus casei Zhang in soymilk and bovine milk during storage.

Science.gov (United States)

Wang, J; Guo, Z; Zhang, Q; Yan, L; Chen, W; Liu, X-M; Zhang, H-P

2009-06-01

Lactobacillus casei Zhang is a novel strain that was screened out of koumiss collected in Inner Mongolia, and our previous research showed that L. casei Zhang has health benefits such as cholesterol-reducing and immunomodulating effects. The fermentation characteristics of L. casei Zhang in soymilk and bovine milk and the transit tolerance of L. casei Zhang in fermented milk products during refrigerated storage for 28 d were assessed. A faster decrease in pH and faster growth of L. casei Zhang during fermentation were observed in soymilk compared with bovine milk at various inoculation rates, probably because of the low pH buffering capacity of soymilk. The fermented bovine milk samples had much higher final titratable acidity (TA) values (between 0.80 and 0.93%) than the soymilk samples (between 0.40 and 0.46%). Dramatic increases in TA values in the fermented soymilk samples during storage were observed, and the TA values of the fermented soymilk samples changed from survival rates of freshly prepared cultures of L. casei Zhang in simulated gastric juice at pH 2.0 and 2.5 were 31 and 69%, respectively, and the delivery of L. casei Zhang through fermented soymilk and bovine milk significantly improved the viability of L. casei Zhang in simulated gastric transit. Lactobacillus casei Zhang showed good tolerance to simulated gastric juice and intestinal juice in the fermented soymilk and bovine milk samples, and maintained high viability (>10(8) cfu/g) during storage at 4 degrees C for 28 d. Our results indicated that both soymilk and bovine milk could serve as vehicles for delivery of probiotic L. casei Zhang, and further research is needed to elucidate the mechanism of the change in pH and TA of L. casei Zhang in fermented milk samples during fermentation and storage and to understand the difference between soy- and milk-based systems.

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.

Fermentation reactions of Erysipelothrix rhusiopathiae.

Science.gov (United States)

WHITE, T G; SHUMAN, R D

1961-10-01

White, Thomas G. (U. S. Department of Agriculture, Ames, Iowa), and Richard D. Shuman. Fermentation reactions of Erysipelothrix rhusiopathiae. J. Bacteriol. 82:595-599. 1961.-A study was made to determine the effect of four different basal media, to which fermentable carbon compounds had been added, upon 22 selected strains of Erysipelothrix rhusiopathiae (insidiosa). Acid production was measured by (i) chemical indicator, (ii) change in pH, and (iii) production of titrable acidity. At least two determinations, usually four, were made for each test on each strain. The fermentation pattern varied according to the medium, the indicator, and the method of measuring acid production. Andrade's base plus serum was the most dependable medium because it permitted the least variation in the total number of different patterns. Of the three methods used to measure acid production, the chemical indicator gave the most valid and reproducible results. The within-strain variation was not extreme and most strains persisted in a given fermentation pattern under like conditions of growth and acid production. Results of the study indicated that, regardless of the medium and indicator routinely used, one should be familiar with the fermentation pattern of known strains of the erysipelas organism.

Application of acetate buffer in pH adjustment of sorghum mash and its influence on fuel ethanol fermentation.

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Zhao, Renyong; Bean, Scott R; Crozier-Dodson, Beth Ann; Fung, Daniel Y C; Wang, Donghai

2009-01-01

A 2 M sodium acetate buffer at pH 4.2 was tried to simplify the step of pH adjustment in a laboratory dry-grind procedure. Ethanol yields or conversion efficiencies of 18 sorghum hybrids improved significantly with 2.0-5.9% (3.9% on average) of relative increases when the method of pH adjustment changed from traditional HCl to the acetate buffer. Ethanol yields obtained using the two methods were highly correlated (R (2) = 0.96, P ethanol production were inhibited during exponential phase but promoted during stationary phase. The maximum growth rate constants (mu(max)) were 0.42 and 0.32 h(-1) for cells grown in mashes with pH adjusted by HCl and the acetate buffer, respectively. Viable cell counts of yeast in mashes with pH adjusted by the acetate buffer were 36% lower than those in mashes adjusted by HCl during stationary phase. Coupled to a 5.3% relative increase in ethanol, a 43.6% relative decrease in glycerol was observed, when the acetate buffer was substituted for HCl. Acetate helped to transfer glucose to ethanol more efficiently. The strain tested did not use acetic acid as carbon source. It was suggested that decreased levels of ATP under acetate stress stimulate glycolysis to ethanol formation, increasing its yield at the expense of biomass and glycerol production.

Effects of fermentation conditions on the production of 4-α ...

African Journals Online (AJOL)

ajl yemi

2011-11-30

Nov 30, 2011 ... studied the recombinant protein of human IGF-1 in rich and minimal ... recombinant protein A-β-lactamase compared to the medium pH at 7.0. ... shake flask fermentation and provided desired conditions for fermentation in 5 L ..... expression kinetics study in bioreactor, which would help to enhance cell ...

Influence of Fermentation and Drying Materials on the Contamination of Cocoa Beans by Ochratoxin A

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Sébastien Djédjé Dano

2013-11-01

Full Text Available Ochratoxin A (OTA is a mycotoxin produced mainly by species of Aspergillus and Penicillium. Contamination of food with OTA is a major consumer health hazard. In Cote D’Ivoire, preventing OTA contamination has been the subject of extensive study. The current study was conducted to evaluate the influence of fermentation and drying materials on the OTA content in cocoa. For each test, 7000 intact cocoa pods were collected, split open to remove the beans, fermented using 1 of 3 different materials, sun-dried on 1 of 3 different platform types and stored for 30 days. A total of 22 samples were collected at each stage of post-harvesting operations. The OTA content in the extracted samples was then quantified by high-performance liquid chromatography. OTA was detected in beans at all stages of post-harvesting operations at varying levels: pod-opening (0.025 ± 0.02 mg/kg, fermentation (0.275 ± 0.2 mg/kg, drying (0.569 ± 0.015 mg/kg, and storage (0.558 ± 0.04 mg/kg. No significant relationships between the detected OTA level and the materials used in the fermentation and drying of cocoa were observed.

Preparation of lactic acid bacteria fermented wheat-yoghurt mixtures.

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Magala, Michal; Kohajdová, Zlatica; Karovičová, Jolana

2013-01-01

Tarhana, a wheat-yoghurt fermented mixture, is considered as a good source of saccharides, proteins, some vitamins and minerals. Moreover, their preparation is inexpensive and lactic acid fermentation offers benefits like product preservation, enhancement of nutritive value and sensory properties improvement. The aim of this work was to evaluate changes of some chemical parameters during fermentation of tarhana, when the level of salt and amount of yoghurt used were varied. Some functional and sensory characteristics of the fi nal product were also determined. Chemical analysis included determination of pH, titrable acidity, content of reducing saccharides, lactic, acetic and citric acid. Measured functional properties of tarhana powder were foaming capacity, foam stability, water absorption capacity, oil absorption capacity and emulsifying activity. Tarhana soups samples were evaluated for their sensory characteristics (colour, odor, taste, consistency and overall acceptability). Fermentation of tarhana by lactic acid bacteria and yeasts led to decrease in pH, content of reducing saccharides and citric acid, while titrable acidity and concentration of lactic and acetic acid increased. Determination of functional properties of tarhana powder showed, that salt absence and increased amount of yoghurt in tarhana recipe reduced foaming capacity and oil absorption capacity, whereas foam stability and water absorption capacity were improved. Sensory evaluation of tarhana soups showed that variations in tarhana recipe adversly affected sensory parameters of fi nal products. Variations in tarhana recipe (salt absence, increased proportion of yoghurt) led to changes in some chemical parameters (pH, titrable acidity, reducing saccharides, content of lactic, acetic and citric acid). Functional properties were also affected with changed tarhana recipe. Sensory characteristics determination showed, that standard tarhana fermented for 144 h had the highest overall acceptability.

Influence of inoculation levels and processing parameters on the survival of Campylobacter jejuni in German style fermented turkey sausages.

Science.gov (United States)

Alter, Thomas; Bori, Anouchka; Hamedi, Ahmad; Ellerbroek, Lüppo; Fehlhaber, Karsten

2006-10-01

This study investigated the influence of inoculum levels and manufacturing methods on the survival of Campylobacter (C.) jejuni in raw fermented turkey sausages. Sausages were prepared and inoculated with C. jejuni. After inoculation, these sausages were processed and ripened for 8 days. Samples were taken throughout the ripening process. The presence of C. jejuni was established bacteriologically. Additionally, lactic acid bacteria were enumerated, pH values and water activity were measured to verify the ripening process. To detect changes in genotype and verify the identity of the recovered clones, AFLP analysis was carried out on the re-isolated strains. Whereas no C. jejuni were detectable when inoculating the sausages with the lowest inoculum (0.08-0.44 log(10) cfu/g sausage emulsion), C. jejuni were detectable for 12-24h by enrichment when inoculated with approximately 2 log(10) cfu/g. After inoculation with 4 and 6 log(10) cfu/g respectively, C. jejuni were detectable without enrichment for 12-48 h and by enrichment for 144 h at the most. The greatest decrease of the C. jejuni population occurred during the first 4 h of ripening. Only a very high inoculum level allowed the survival of the organism during a fermentation process and during ripening to pose a potential risk for consumers. Lower initial Campylobacter inoculums will be eliminated during proper ripening of the sausages, if sufficient decrease in water activity and pH-value is ensured.

Hydrogen production from palm oil mill effluent by fermentation

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Tanisho, S.; Shimazaki, T. [Yokohama National Univ., Shigeharu TANISHO and Tsuruyo SHIMAZAKI, Yokohama (Japan)

2003-09-01

Hydrogen production by fermentation was examined by using palm oil mill effluent. Clostridium butyricum produced more than 2.2 NL of hydrogen from 1 L of raw POME at pH 5.0, and Enterobacter aerogenes produced ca. 1.9 NL at pH 6.0. While from the culture liquid added 1% of peptone on the raw POME, C. butyricum produced more than 3.3 NL and also E. aerogenes 3.4 NL at pH 6.0 and 5.0, respectively. In this manner, the addition of nitrogen source to the POME liquid exerted an influence on the volume of hydrogen production. Since Aspergillus niger has ability to produce cellulase, co-cultivation of C.butyricum with A. niger was tried to utilize celluloses in the POME. Against our expectations, however, the results were lower productivities than pure cultivation's. We analyzed the components of POME by liquid chromatography and capillary electrophoresis before and after cultivation. The main substrate for hydrogen production was found to be glycerol. (authors)

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

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

2016-11-01

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

In vitro batch fecal fermentation comparison of gas and short-chain fatty acid production using "slowly fermentable" dietary fibers.

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Kaur, Amandeep; Rose, Devin J; Rumpagaporn, Pinthip; Patterson, John A; Hamaker, Bruce R

2011-01-01

Sustained colonic fermentation supplies beneficial fermentative by-products to the distal colon, which is particularly prone to intestinal ailments. Blunted/delayed initial fermentation may also lead to less bloating. Previously, we reported that starch-entrapped alginate-based microspheres act as a slowly fermenting dietary fiber. This material was used in the present study to provide a benchmark to compare to other "slowly fermentable" fibers. Dietary fibers with previous reports of slow fermentation, namely, long-chain inulin, psyllium, alkali-soluble corn bran arabinoxylan, and long-chain β-glucan, as well as starch-entrapped microspheres were subjected to in vitro upper gastrointestinal digestion and human fecal fermentation and measured over 48 h for pH, gas, and short-chain fatty acids (SCFA). The resistant fraction of cooked and cooled potato starch was used as another form of fermentable starch and fructooligosaccharides (FOS) served as a fast fermenting control. Corn bran arabinoxylan and long-chain β-glucan initially appeared slower fermenting with comparatively low gas and SCFA production, but later fermented rapidly with little remaining in the final half of the fermentation period. Long-chain inulin and psyllium had slow and moderate, but incomplete, fermentation. The resistant fraction of cooked and cooled potato starch fermented rapidly and appeared similar to FOS. In conclusion, compared to the benchmark slowly fermentable starch-entrapped microspheres, a number of the purported slowly fermentable fibers fermented fairly rapidly overall and, of this group, only the starch-entrapped microspheres appreciably fermented in the second half of the fermentation period. Consumption of dietary fibers, particularly commercial prebiotics, leads to uncomfortable feelings of bloating and flatulence due to their rapid degradation in our large intestine. This article employs claimed potential slowly fermenting fibers and compares their fermentation rates

Xylanase from Fusarium heterosporum: Properties and influence of ...

African Journals Online (AJOL)

Unioeste

2014-02-26

Feb 26, 2014 ... influence of thiol compounds on xylanase activity. Paulo Ricardo ... and the extraction of plant oil, coffee and starch (Ahmed ... of F. heterosporum on 5 g of various carbon sources ... brewing residue under solid-state fermentation (fungal strain and .... active within the acidic pH range of 4.5 to 5.5 and.

Identification of the potential inhibitors of malolactic fermentation in wines

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Renata Vieira da MOTA

2017-10-01

Full Text Available Abstract This exploratory work aims to identify the potential inhibitors of lactic bacterial growth and to propose enological practices to guarantee the occurrence of spontaneous malolactic fermentation (MLF in wines from traditional and double-pruning management harvests in southeast Brazil. One white wine from a summer harvest and one red wine from a winter harvest that failed to complete MLF were utilized as comparative models to identify inhibitor compounds to lactic bacteria. Wine composition, alcoholic-fermentation temperature and bacterial strain contribute to the success or failure of MLF. Temperatures below 12 °C during alcoholic fermentation decrease lactic bacterial metabolism and may impair the bacteria’s growth after yeast cells lysis. A must pH below 3.2 in a summer harvest impairs bacterial growth, and the association of low pH with a free-SO2 concentration above 10 mg L-1 may inhibit MLF. For grapes with a high sugar content, harvested in the winter cycle, enologists should keep the alcohol content below 15% and control the alcoholic-fermentation temperature.

Effects of different ratios and storage periods of liquid brewer's yeast mixed with cassava pulp on chemical composition, fermentation quality and in vitro ruminal fermentation.

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Kamphayae, Sukanya; Kumagai, Hajime; Angthong, Wanna; Narmseelee, Ramphrai; Bureenok, Smerjai

2017-04-01

This study aims to evaluate the chemical composition, fermentation quality and in vitro ruminal fermentation of various ratios and storage periods of liquid brewer's yeast (LBY) mixed with cassava pulp (CVP). Four mixtures of fresh LBY and CVP were made (LBY0, LBY10, LBY20, and LBY30 for LBY:CVP at 0:100, 10:90, 20:80, and 30:70, respectively) on a fresh matter basis, in 500 g in plastic bags and stored at 30 to 32°C. After storage, the bags were opened weekly from weeks 0 to 4. Fermentation quality and in vitro gas production (IVGP) were determined, as well as the dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), neutral detergent fiber, acid detergent fiber and acid detergent lignin contents. The contents of CP and EE increased, whereas all other components decreased, in proportion to LBY inclusion (pcontents gradually decreased in weeks 3 and 4 (pcontents were lowest in week 0. The pH, ammonia nitrogen per total nitrogen (NH 3 -N/TN) and V-score in each mixture and storage period demonstrated superior fermentation quality (pH≤4.2, NH 3 -N/TN≤12.5%, and V-score>90%). The pH increased and NH 3 -N/TN decreased, with proportionate increases of LBY, whereas the pH decreased and NH 3 -N/TN increased, as the storage periods were extended (pcontent, while decreasing IVGP, without decreasing fermentation quality and IVOMD. In addition, a preservation period of up to four weeks can guarantee superior fermentation quality in all types of mixtures. Therefore, we recommend limiting the use of CVP as a feed ingredient, given its low nutritional value and improving feed quality with the inclusion of LBY.

Effect of pulp preconditioning on acidification, proteolysis, sugars and free fatty acids concentration during fermentation of cocoa (Theobroma cacao) beans.

Science.gov (United States)

Afoakwa, Emmanuel Ohene; Quao, Jennifer; Budu, Agnes Simpson; Takrama, Jemmy; Saalia, Firibu Kwesi

2011-11-01

Changes in acidification, proteolysis, sugars and free fatty acids (FFAs) concentrations of Ghanaian cocoa beans as affected by pulp preconditioning (pod storage or PS) and fermentation were investigated. Non-volatile acidity, pH, proteolysis, sugars (total, reducing and non-reducing) and FFAs concentrations were analysed using standard methods. Increasing PS consistently decreased the non-volatile acidity with concomitant increase in pH during fermentation of the beans. Fermentation decreased the pH of the unstored beans from 6.7 to 4.9 within the first 4 days and then increased slightly again to 5.3 by the sixth day. Protein, total sugars and non-reducing sugars decreased significantly (p cocoa beans was largely affected by fermentation than by PS.

Influence of pH on pesticide sorption by soil containing wheat residue-derived char

International Nuclear Information System (INIS)

Sheng Guangyao; Yang Yaning; Huang Minsheng; Yang Kai

2005-01-01

Field burning of crop residues incorporates resulting chars into soil and may thus influence the environmental fate of pesticides in the soil. This study evaluated the influence of pH on the sorption of diuron, bromoxynil, and ametryne by a soil in the presence and absence of a wheat residue-derived char. The sorption was measured at pHs ∼3.0 and ∼7.0. Wheat char was found to be a highly effective sorbent for the pesticides, and its presence (1% by weight) in soil contributed >70% to the pesticide sorption (with one exception). The sorption of diuron was not influenced by pH, due to its electroneutrality. Bromoxynil becomes dissociated at high pHs to form anionic species. Its sorption by soil and wheat char was lower at pH ∼7.0 than at pH ∼3.0, probably due to reduced partition of the anionic species of bromoxynil into soil organic matter and its weak interaction with the carbon surface of the char. Ametryne in its molecular form at pH ∼7.0 was sorbed by char-amended soil via partitioning into soil organic matter and interaction with the carbon surface of the char. Protonated ametryne at pH ∼3.0 was substantially sorbed by soil primarily via electrostatic forces. Sorption of protonated ametryne by wheat char was also significant, likely due not only to the interaction with the carbon surface but also to interactions with hydrated silica and surface functional groups of the char. Sorption of ametryne by char-amended soil at pH ∼3.0 was thus influenced by both the soil and the char. Environmental conditions may thus significantly influence the sorption and behavior of pesticides in agricultural soils containing crop residue-derived chars. - Wheat char was effective for adsorption of pesticides in soil, with efficacy varying with pH and particular pesticides

Influence of pH on pesticide sorption by soil containing wheat residue-derived char

Energy Technology Data Exchange (ETDEWEB)

Sheng Guangyao [Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, AR 72701 (United States)]. E-mail: gsheng@uark.edu; Yang Yaning [Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, AR 72701 (United States); Huang Minsheng [Department of Environmental Science and Technology, East China Normal University, Shanghai 200062 (China); Yang Kai [Department of Environmental Science and Technology, East China Normal University, Shanghai 200062 (China)

2005-04-01

Field burning of crop residues incorporates resulting chars into soil and may thus influence the environmental fate of pesticides in the soil. This study evaluated the influence of pH on the sorption of diuron, bromoxynil, and ametryne by a soil in the presence and absence of a wheat residue-derived char. The sorption was measured at pHs {approx}3.0 and {approx}7.0. Wheat char was found to be a highly effective sorbent for the pesticides, and its presence (1% by weight) in soil contributed >70% to the pesticide sorption (with one exception). The sorption of diuron was not influenced by pH, due to its electroneutrality. Bromoxynil becomes dissociated at high pHs to form anionic species. Its sorption by soil and wheat char was lower at pH {approx}7.0 than at pH {approx}3.0, probably due to reduced partition of the anionic species of bromoxynil into soil organic matter and its weak interaction with the carbon surface of the char. Ametryne in its molecular form at pH {approx}7.0 was sorbed by char-amended soil via partitioning into soil organic matter and interaction with the carbon surface of the char. Protonated ametryne at pH {approx}3.0 was substantially sorbed by soil primarily via electrostatic forces. Sorption of protonated ametryne by wheat char was also significant, likely due not only to the interaction with the carbon surface but also to interactions with hydrated silica and surface functional groups of the char. Sorption of ametryne by char-amended soil at pH {approx}3.0 was thus influenced by both the soil and the char. Environmental conditions may thus significantly influence the sorption and behavior of pesticides in agricultural soils containing crop residue-derived chars. - Wheat char was effective for adsorption of pesticides in soil, with efficacy varying with pH and particular pesticides.

The influence of pH on the adsorption of lead by Na-clinoptilolite ...

African Journals Online (AJOL)

The influence of pH on the adsorption of lead by Na-clinoptilolite: Kinetic and equilibrium studies. ... At high pH of the contact solution, the adsorption process occurs by ion exchange and at low pH; i.e., it is physical. The variation of the Gibbs free energy demonstrates that adsorption occurs spontaneously. The process was ...

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

Science.gov (United States)

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

2013-01-01

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

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

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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.

The influence of petroleum products on the methane fermentation process.

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Choromański, Paweł; Karwowska, Ewa; Łebkowska, Maria

2016-01-15

In this study the influence of the petroleum products: diesel fuel and spent engine oil on the sewage sludge digestion process and biogas production efficiency was investigated. Microbiological, chemical and enzymatic analyses were applied in the survey. It was revealed that the influence of the petroleum derivatives on the effectiveness of the methane fermentation of sewage sludge depends on the type of the petroleum product. Diesel fuel did not limit the biogas production and the methane concentration in the biogas, while spent engine oil significantly reduced the process efficacy. The changes in physical-chemical parameters, excluding COD, did not reflect the effect of the tested substances. The negative influence of petroleum products on individual bacterial groups was observed after 7 days of the process, while after 14 days probably some adaptive mechanisms appeared. The dehydrogenase activity assessment was the most relevant parameter to evaluate the effect of petroleum products contamination. Diesel fuel was probably used as a source of carbon and energy in the process, while the toxic influence was observed in case of spent engine oil. Copyright © 2015 Elsevier B.V. All rights reserved.

The γ-aminobutyric acid-producing ability under low pH conditions of lactic acid bacteria isolated from traditional fermented foods of Ishikawa Prefecture, Japan, with a strong ability to produce ACE-inhibitory peptides.

Science.gov (United States)

Barla, Florin; Koyanagi, Takashi; Tokuda, Naoko; Matsui, Hiroshi; Katayama, Takane; Kumagai, Hidehiko; Michihata, Toshihide; Sasaki, Tetsuya; Tsuji, Atsushi; Enomoto, Toshiki

2016-06-01

Many traditional fermented products are onsumed in Ishikawa Prefecture, Japan, such as kaburazushi , narezushi , konkazuke , and ishiru. Various kinds of lactic acid bacteria (LAB) are associated with their fermentation, however, characterization of LAB has not yet been elucidated in detail. In this study, we evaluated 53 isolates of LAB from various traditional fermented foods by taxonomic classification at the species level by analyzing the 16S ribosomal RNA gene (rDNA) sequences and carbohydrate assimilation abilities. We screened isolates that exhibited high angiotensin-converting enzyme (ACE) inhibitory activities in skim milk or soy protein media and produced high γ-aminobutyric acid (GABA) concentrations in culture supernatants when grown in de Man Rogosa Sharpe broth in the presence of 1% (w/v) glutamic acid. The results revealed that 10 isolates, i.e., Lactobacillus buchneri (2 isolates), Lactobacillus brevis (6 isolates), and Weissella hellenica (2 isolates) had a high GABA-producing ability of >500 mg/100 ml after 72 h of incubation at 35 °C. The ACE inhibitory activity of the whey cultured with milk protein by using L. brevis (3 isolates), L. buchneri (2 isolates), and W. hellenica (2 isolates) was stronger than that of all whey cultured with soy protein media, and these IC 50 were GABA-producing activities at pH 3, suggesting that they could be powerful candidates for use in the fermentation of food materials having low pH.

Production of ethanol from a mixture of waste paper and kitchen waste via a process of successive liquefaction, presaccharification, and simultaneous saccharification and fermentation.

Science.gov (United States)

Nishimura, Hiroto; Tan, Li; Kira, Noriko; Tomiyama, Shigeo; Yamada, Kazuo; Sun, Zhao-Yong; Tang, Yue-Qin; Morimura, Shigeru; Kida, Kenji

2017-09-01

Efficient ethanol production from waste paper requires the addition of expensive nutrients. To reduce the production cost of ethanol from waste paper, a study on how to produce ethanol efficiently by adding kitchen waste (potentially as a carbon source, nutrient source, and acidity regulator) to waste paper was performed and a process of successive liquefaction, presaccharification, and simultaneous saccharification and fermentation (L+PSSF) was developed. The individual saccharification performances of waste paper and kitchen waste were not influenced by their mixture. Liquefaction of kitchen waste at 90°C prior to presaccharification and simultaneous saccharification and fermentation (PSSF) was essential for efficient ethanol fermentation. Ethanol at concentrations of 46.6 or 43.6g/l was obtained at the laboratory scale after fermentation for 96h, even without pH adjustment and/or the addition of extra nutrients. Similarly, ethanol at a concentration of 45.5g/l was obtained at the pilot scale after fermentation for 48h. The ethanol concentration of L+PSSF of the mixture of waste paper and kitchen waste was comparable to that of PSSF of waste paper with added nutrients (yeast extract and peptone) and pH adjustment using H 2 SO 4 , indicating that kitchen waste is not only a carbon source but also an excellent nutrient source and acidity regulator for fermentation of the mixture of waste paper and kitchen waste. Copyright © 2017. Published by Elsevier Ltd.

Microprofiles of oxygen, redox potential, and pH, and microbial fermentation products in the highly alkaline gut of the saprophagous larva of Penthetria holosericea (Diptera: Bibionidae)

KAUST Repository

Šustr, Vladimír

2014-08-01

The saprophagous larvae of bibionid flies harbor bacteria in their alkaline intestinal tracts, but little is known about the contribution of the gut microbiota to the digestion of their recalcitrant diet. In this study, we measured oxygen and hydrogen partial pressure, redox potential and pH in the midgut, gastric caeca and hindgut of larvae of the bibionid fly Penthetria holosericea with Clark-type O2 and H2 microsensors, platinum redox microelectrodes, and LIX-type pH microelectrodes. The center of the midgut lumen was anoxic, whereas gastric caeca and hindgut were hypoxic. However, redox potential profiles indicated oxidizing conditions throughout the gut, with lowest values in the midgut (+20 to +60mV). Hydrogen production was not detected. The midgut was extremely alkaline (pH around 11), whereas hindgut and gastric caeca were neutral to slightly alkaline. While HPLC analysis showed high concentrations of glucose in the midgut (15mM) and gastric caeca (27mM), the concentrations of microbial fermentation products such as lactate (2-4mM), acetate (<1mM) and succinate (<0.5mM) were low in all gut regions, suggesting that the contribution of microorganisms to the digestive process, particularly in the alkaline midgut, is only of minor importance. We conclude that the digestive strategy of the saprophytic larva of P. holosericea, which feeds selectively on decomposed leaves and its own microbe-rich faeces, differs fundamentally from those of detritivorous and humivorous insects, which host a highly active, fermentative microbiota in their alkaline midgut or hindgut compartments. © 2014 Elsevier Ltd.

Kombucha fermentation and its antimicrobial activity.

Science.gov (United States)

Sreeramulu, G; Zhu, Y; Knol, W

2000-06-01

Kombucha was prepared in a tea broth (0.5% w/v) supplemented with sucrose (10% w/v) by using a commercially available starter culture. The pH decreased steadily from 5 to 2.5 during the fermentation while the weight of the "tea fungus" and the OD of the tea broth increased through 4 days of the fermentation and remained fairly constant thereafter. The counts of acetic acid-producing bacteria and yeasts in the broth increased up to 4 days of fermentation and decreased afterward. The antimicrobial activity of Kombucha was investigated against a number of pathogenic microorganisms. Staphylococcus aureus, Shigella sonnei, Escherichia coli, Aeromonas hydrophila, Yersinia enterolitica, Pseudomonas aeruginosa, Enterobacter cloacae, Staphylococcus epidermis, Campylobacter jejuni, Salmonella enteritidis, Salmonella typhimurium, Bacillus cereus, Helicobacterpylori, and Listeria monocytogenes were found to be sensitive to Kombucha. According to the literature on Kombucha, acetic acid is considered to be responsible for the inhibitory effect toward a number of microbes tested, and this is also valid in the present study. However, in this study, Kombucha proved to exert antimicrobial activities against E. coli, Sh. sonnei, Sal. typhimurium, Sal. enteritidis, and Cm. jejuni, even at neutral pH and after thermal denaturation. This finding suggests the presence of antimicrobial compounds other than acetic acid and large proteins in Kombucha.

Lactic acid fermentation of human urine to improve its fertilizing value and reduce odour emissions.

Science.gov (United States)

Andreev, N; Ronteltap, M; Boincean, B; Wernli, M; Zubcov, E; Bagrin, N; Borodin, N; Lens, P N L

2017-08-01

During storage of urine, urea is biologically decomposed to ammonia, which can be lost through volatilization and in turn causes significant unpleasant smell. In response, lactic acid fermentation of urine is a cost-effective technique to decrease nitrogen volatilization and reduce odour emissions. Fresh urine (pH = 5.2-5.3 and NH 4 + -N = 1.2-1.3 g L -1 ) was lacto-fermented for 36 days in closed glass jars with a lactic acid bacterial inoculum from sauerkraut juice and compared to untreated, stored urine. In the lacto-fermented urine, the pH was reduced to 3.8-4.7 and the ammonium content by 22-30%, while the pH of the untreated urine rose to 6.1 and its ammonium content increased by 32% due to urea hydrolysis. The concentration of lactic acid bacteria in lacto-fermented urine was 7.3 CFU ml -1 , suggesting that urine is a suitable growth medium for lactic acid bacteria. The odour of the stored urine was subjectively perceived by four people to be twice as strong as that of lacto-fermented samples. Lacto-fermented urine induced increased radish germination compared to stored urine (74-86% versus 2-31%). Adding a lactic acid bacterial inoculum to one week old urine in the storage tanks in a urine-diverting dry toilet reduced the pH from 8.9 to 7.7 after one month, while the ammonium content increased by 35%, probably due to the high initial pH of the urine. Given that the hydrolyzed stale urine has a high buffering capacity, the lactic acid bacterial inoculum should be added to the urine storage tank of a UDDT before urine starts to accumulate there to increase the efficiency of the lactic acid fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.

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...

Antagonistic effect of chosen lactic acid bacteria strains on Yersinia enterocolitica species in model set-ups, meat and fermented sausages.

Science.gov (United States)

Gomółka-Pawlicka, M; Uradziński, J

2003-01-01

The present study was aimed at determining the influence of 15 strains of lactic acid bacteria on the growth of 8 Yersinia enterocolitica strains in model set-ups, and in meat and ageing fermented sausages. The investigations were performed within the framework of three alternate stages which differed in respect to the products studied, the number of Lactobacillus sp. strains and, partly, methodological approach. The ratio between lactic acid bacteria and Yersinia enterocolitica strains studied was, depending on the variant of experiment, 1:1, 1:2 and 2:1, respectively. The study also considered water activity (aw) and pH of the products investigated. The results suggest that all the lactic acid bacteria strains used within the framework of the model set-ups had antagonistic effect on all the Salmonella sp. strains. However, this ability was not observed with respect to of tested lactic acid bacteria strains in meat and fermented sausage. This ability was possessed by one of the strains investigated--Lactobacillus helveticus T 78. The temperature and time of the incubation of sausages, but not aw and pH, were found to have a distinct influence on the antagonistic interaction between the bacteria tested.

Effect of sucrose concentration on the products of Kombucha fermentation on molasses.

Science.gov (United States)

Malbaša, R; Lončar, E; Djurić, M; Došenović, I

2008-06-01

Fermentation of 1.5g/l of Indian black tea, sweetened with adequate quantities of molasses (containing approx. 70g/l, 50g/l and 35g/l of sucrose), was conducted using domestic Kombucha. Inoculation was performed with 10% of fermentation broth from a previous process. The fermentation in cylindrical vessels containing 2l of liquid phase, was carried out at 22±1°C for 14 days, with periodical sampling, to measure pH, content of acids (total, acetic and l-lactic), content of remaining sucrose, and the yield of biomass at the end of fermentation. A product with 70g/l sucrose from molasses corresponds to an optimal concentration of carbon source, which provided metabolites with high pH, a low content of less desired acetic acid, a high content of highly desired l-lactic acid, an acceptable content of total acids and the highest possible level of utilisation of sucrose. Copyright © 2007 Elsevier Ltd. All rights reserved.

A Novel Technique that Enables Efficient Conduct of Simultaneous Isomerization and Fermentation (SIF) of Xylose

Science.gov (United States)

Rao, Kripa; Chelikani, Silpa; Relue, Patricia; Varanasi, Sasidhar

Of the sugars recovered from lignocellulose, D-glucose can be readily converted into ethanol by baker's or brewer's yeast (Saccharomyces cerevisiae). However, xylose that is obtained by the hydrolysis of the hemicellulosic portion is not fermentable by the same species of yeasts. Xylose fermentation by native yeasts can be achieved via isomerization of xylose to its ketose isomer, xylulose. Isomerization with exogenous xylose isomerase (XI) occurs optimally at a pH of 7-8, whereas subsequent fermentation of xylulose to ethanol occurs at a pH of 4-5. We present a novel scheme for efficient isomerization of xylose to xylulose at conditions suitable for the fermentation by using an immobilized enzyme system capable of sustaining two different pH microenvironments in a single vessel. The proof-of-concept of the two-enzyme pellet is presented, showing conversion of xylose to xylulose even when the immobilized enzyme pellets are suspended in a bulk solution whose pH is sub-optimal for XI activity. The co-immobilized enzyme pellets may prove extremely valuable in effectively conducting "simultaneous isomerization and fermentation" (SIF) of xylose. To help further shift the equilibrium in favor of xylulose formation, sodium tetraborate (borax) was added to the isomerization solution. Binding of tetrahydroxyborate ions to xylulose effectively reduces the concentration of xylulose and leads to increased xylose isomerization. The formation of tetrahydroxyborate ions and the enhancement in xylulose production resulting from the complexation was studied at two different bulk pH values. The addition of 0.05 M borax to the isomerization solution containing our co-immobilized enzyme pellets resulted in xylose to xylulose conversion as high as 86% under pH conditions that are suboptimal for XI activity. These initial findings, which can be optimized for industrial conditions, have significant potential for increasing the yield of ethanol from xylose in an SIF approach.

Effects of submerged and anaerobic fermentations on cassava flour ...

African Journals Online (AJOL)

Cassava tubers for processing into cassava flour, Lafun a Nigerian locally fermented product was subjected to two different types of fermentations: submerged and anaerobic fermentation for 72 h. Physicochemical changes that occurred during fermentation and their influence on the functional, rheological and sensory ...

Kombucha fermentation on raw extracts of different cultivars of Jerusalem artichoke

Directory of Open Access Journals (Sweden)

Lončar Eva S.

2007-01-01

Full Text Available Kombucha is a symbiosis between yeasts and acetic bacteria. It usually grows on sweetened black tea, but cultivation is possible on many other substrates. Jerusalem artichoke tubers extract is one of them. Tubers are suitable for the dietetic nutrition because of the low monosaccharide content and presence of some polyfructan ingredients which act as prebiotic. Five different cultivars of Jerusalem artichoke were used for the preparation of substrates for kombucha fermentation. The aim of this paper was the investigation of the influence of different Jerusalem artichoke cultivars on metabolic activity of kombucha. Composition of carbohydrates was followed using thin-layer chromatography and pH, reducing sugars content and yield of biomass were measured. Most of the samples with Jerusalem artichoke tubers extract contained fructose, probably small amount of glucose, fructo-oligosaccharides with different degree of polymerization and, inulin. Considering TLC chromatograms, Jerusalem artichoke cultivar did not affect significantly the composition of oligosaccharides in the fermentative liquid, as only minor differences were observed.

Fermentation of D-Tagatose by Human Intestinal Bacteria and Dairy Lactic Acid Bacteria

OpenAIRE

Bertelsen, Hans; Andersen, Hans; Tvede, Michael

2011-01-01

A number of 174 normal or pathogenic human enteric bacteria and dairy lactic acid bacteria were screened for D-tagatose fermentation by incubation for 48 hours. Selection criteria for fermentation employed included a drop in pH below 5.5 and a distance to controls of more than 0.5. Only a few of the normal occurring enteric human bacteria were able to ferment D-tagatose, among those Enterococcus faecalis, Enterococcus faecium and Lactobacillus strains. D-Tagatose fermentation seems to be comm...

Ethanol addition enhances acid treatment to eliminate Lactobacillus fermentum from the fermentation process for fuel ethanol production.

Science.gov (United States)

Costa, M A S; Cerri, B C; Ceccato-Antonini, S R

2018-01-01

Fermentation is one of the most critical steps of the fuel ethanol production and it is directly influenced by the fermentation system, selected yeast, and bacterial contamination, especially from the genus Lactobacillus. To control the contamination, the industry applies antibiotics and biocides; however, these substances can result in an increased cost and environmental problems. The use of the acid treatment of cells (water-diluted sulphuric acid, adjusted to pH 2·0-2·5) between the fermentation cycles is not always effective to combat the bacterial contamination. In this context, this study aimed to evaluate the effect of ethanol addition to the acid treatment to control the bacterial growth in a fed-batch system with cell recycling, using the industrial yeast strain Saccharomyces cerevisiae PE-2. When only the acid treatment was used, the population of Lactobacillus fermentum had a 3-log reduction at the end of the sixth fermentation cycle; however, when 5% of ethanol was added to the acid solution, the viability of the bacterium was completely lost even after the first round of cell treatment. The acid treatment +5% ethanol was able to kill L. fermentum cells without affecting the ethanol yield and with a low residual sugar concentration in the fermented must. In Brazilian ethanol-producing industry, water-diluted sulphuric acid is used to treat the cell mass at low pH (2·0) between the fermentative cycles. This procedure reduces the number of Lactobacillus fermentum from 10 7 to 10 4  CFU per ml. However, the addition of 5% ethanol to the acid treatment causes the complete loss of bacterial cell viability in fed-batch fermentation with six cell recycles. The ethanol yield and yeast cell viability are not affected. These data indicate the feasibility of adding ethanol to the acid solution replacing the antibiotic use, offering a low cost and a low amount of residue in the biomass. © 2017 The Society for Applied Microbiology.

Effect of active acidity on the stability of amylolytic enzymes in fermentation of corn mash

Energy Technology Data Exchange (ETDEWEB)

Zherebtsov, N A; Mal' tsev, P M

1957-01-01

The effect of pH between 6.5 and 3.5 on the activity of ..cap alpha..- and ..beta..-amylases, dextrinase, and on the yield of alcohol in the fermentation of corn mash were investigated. The minimum of unfermented maltose and maximum activity of amylolytic enzymes were found from fermentations between pH 5.5 and 4.9. Under these conditions ..beta..-amylase and dextrinase were unaffected, while ..cap alpha..-amylase activity was reduced to 59.1% initial activity. Considerable inactivation of ..beta..-amylase and dextrinase set in at pH 4.0 and ..cap alpha..-amylase at pH 4.5. The highest yield of alcohol was produced from mash with initial pH 6.0 obtained by addition of sodium hydroxide.

Conversion of rice husk into fermentable sugar by two stage hydrolysis

Science.gov (United States)

Salimi, M. N.; Lim, S. E.; Yusoff, A. H. M.; Jamlos, M. F.

2017-10-01

Rice husks, a complex lignocellulosic biomass which comprised of high cellulose content (38-50%), hemicellulose (23-32%) and lignin (15-25%) possesses the potential to pursue as low cost feedstock for production of ethanol. Dilute sulfuric acid at concentration of 1, 2, 3 (%, v/v) were used for pretreatments at varied hydrolysis time (15-60 min) and enzymatic saccharification at range of 45-60˚C and pH 4.5-6.0 were evaluated for conversion of rice husk’s cellulose and hemicellulose to fermentable sugars. The maximum yield of fermentable sugars from rice husks by dilute sulfuric acid (2%, 60 minutes) was 0.0751 g/l. Total fermentable sugar was identified using dinitrosalicylic acid (DNS) method and expressed in g/l. Enzymatic hydrolysis for conversion of cellulose to fermentable sugar has been studied by applying response surface methodology (RSM) and Analysis of Variance (ANOVA). Two independent variables namely initial pH and incubation temperature were considered using Central Composite Design (CCD). The determination coefficient, R2 obtained was 0.9848. This indicates that 98.48% capriciousness in the respond could be clarified by the ANOVA. Based on the data shown by Design Expert software, the optimum condition for total sugar production was at pH 6.0 and temperature 45˚C as it produced 0.5086 g/l of total sugar.

Production of Extracellular Lipase from Aspergillus niger by Solid-State Fermentation

Directory of Open Access Journals (Sweden)

Janny Coca Armas

2006-01-01

Full Text Available Lipase production in Aspergillus niger J-1 was tested using both submerged fermentation (SmF and solid-state fermentation (SSF on a mineral culture medium and wheat bran, respectively. The optimization of the culture medium was carried out for both SmF and SSF. The maximum lipase activity, 1.46 IU/mL, was obtained during the submerged fermentation in a medium containing glucose at 2 % and olive oil at 2 % under conditions of 1 vvm and 450 m–1. However, 9.14 IU/g of dry solid substrate equivalent to 4.8 IU/mL of lipase activity was reached using solid-state fermentation process with a medium containing 0.75 % of ammonium sulphate and 0.34 % of urea. The optimum pH and temperature for enzymatic activity were pH=6 and 40 °C, respectively. The enzyme also exhibited 80 % of its initial activity in neutral and mildly acid media and at temperatures between 20 and 30 °C for a period of 24 hours.

Production and Partial Purification of a Neutral Metalloprotease by Fungal Mixed Substrate Fermentation

Directory of Open Access Journals (Sweden)

Alagarsamy Sumantha

2005-01-01

Full Text Available Five strains of fungi belonging to Aspergillus sp. were evaluated by casein agar plate assay and a wheat bran-based solid-state fermentation for selecting a neutral protease-producing culture. Based on the results, A. oryzae NRRL 2217 was selected for further studies. Sixteen different agro-industrial residues were evaluated for their potential to serve as a substrate for neutral protease production by this fungal strain. Results showed that a combination of coconut oil cake and wheat bran in the mass ratio of 1:3 was the best substrate for enzyme production. Various process parameters influencing protease production including fermentation time, initial moisture content, and fermentation temperature were optimised. The medium was supplemented with different nutrients in the form of organic and inorganic nitrogen and carbon sources. Supplementation of chitin increased the enzyme production significantly. Ammonium nitrate as inorganic nitrogen supplement slightly enhanced enzyme production. No organic nitrogen supplement was effective enhancer of enzyme production. Fermentation was performed under optimised conditions (initial moisture content V/m = 50 %, temperature 30 °C, 48 h. Partial purification of the enzyme resulted in a 3-fold increase in the specific activity of the enzyme. The partially purified enzyme was characterised by various features that govern the enzyme activity such as assay temperature, assay pH and substrate concentration. The effect of various metal ions and known protease inhibitors on the enzyme activity was also studied. The enzyme was found to be stable in pH range 7.0–7.5, and at temperature of 50 °C for 35 min. By the activating effect of divalent cations (Mg2+, Ca2+, Fe2+ and inhibiting effect of certain chelating agents (EGTA, EDTA, the enzyme was found to be a metalloprotease.

Influence of yeast immobilization on fermentation and aldehyde reduction during the production of alcohol-free beer

NARCIS (Netherlands)

Iersel, van M.F.M.; Brouwer-Post, E.; Rombouts, F.M.; Abee, T.

2000-01-01

Production of alcohol-free beer by limited fermentation is optimally performed in a packed-bed reactor. This highly controllable system combines short contact times between yeast and wort with the reduction of off-flavors to concentrations below threshold values. In the present study, the influence

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

Science.gov (United States)

Buehler, Edward A.; Mesbah, Ali

2016-01-01

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

Fermentation Profiles of Wheat Dextrin, Inulin and Partially Hydrolyzed Guar Gum Using an in Vitro Digestion Pretreatment and in Vitro Batch Fermentation System Model

Directory of Open Access Journals (Sweden)

Joanne Slavin

2013-05-01

Full Text Available This study investigated the fermentation and microbiota profiles of three fibers, wheat dextrin (WD, partially hydrolyzed guar gum (PHGG, and inulin, since little is known about the effects of WD and PHGG on gut microbiota. A treatment of salivary amylase, pepsin, and pancreatin was used to better physiologic digestion. Fibers (0.5 g were fermented in triplicate including a control group without fiber for 0, 4, 8, 12, and 24 h. Analysis of pH, gas volume, hydrogen and methane gases, and short chain fatty acid (SCFA concentrations were completed at each time point. Quantitative polymerase chain reaction (qPCR was used to measure Bifidobacteria and Lactobacillus CFUs at 24 h. WD produced the least gas during fermentation at 8, 12, and 24 h (P < 0.0001, while inulin produced the most by 8 h (P < 0.0001. Each fiber reached its lowest pH value at different time points with inulin at 8 h (mean ± SE (5.94 ± 0.03, PHGG at 12 h (5.98 ± 0.01, and WD at 24 h (6.17 ± 0.03. All fibers had higher total SCFA concentrations compared to the negative control (P < 0.05 at 24 h. At 24 h, inulin produced significantly (P = 0.0016 more butyrate than WD with PHGG being similar to both. An exploratory microbial analysis (log10 CFU/µL showed WD had CFU for Bifidobacteria (6.12 and Lactobacillus (7.15 compared with the control (4.92 and 6.35, respectively. Rate of gas production is influenced by fiber source and may affect tolerance in vivo. Exploratory microbiota data hint at high levels of Bifidobacteria for WD, but require more robust investigation to corroborate these findings.

Fermentation of enset (Ensete ventricosum) in the Gamo highlands of Ethiopia: Physicochemical and microbial community dynamics.

Science.gov (United States)

Andeta, A F; Vandeweyer, D; Woldesenbet, F; Eshetu, F; Hailemicael, A; Woldeyes, F; Crauwels, S; Lievens, B; Ceusters, J; Vancampenhout, K; Van Campenhout, L

2018-08-01

Enset (Ensete ventricosum) provides staple food for 15 million people in Ethiopia after fermentation into kocho. The fermentation process has hardly been investigated and is prone to optimization. The aim of this study was to investigate the physicochemical and microbial dynamics of fermentation practices in the Gamo highlands. These practices show local variation, but two steps were omnipresent: scraping of the pseudostem and fermenting it in a pit or a bamboo basket. Enset plants were fragmented and fermented for two months in order to investigate the physicochemical (temperature, moisture content, pH and titratable acidity) and microbial dynamics (total viable aerobic counts, counts of Enterobacteriaceae, lactic acid bacteria, yeasts and moulds and Clostridium spores counts, and Illumina Miseq sequencing). Samples were taken on days 1, 7, 15, 17, 31 and 60. The pH decreased, whereas the titratable acidity increased during fermentation. Of all counts those of lactic acid bacteria and Clostridium spores increased during fermentation. Leuconostoc mesenteroides initiated the fermentation. Later on, Prevotella paludivivens, Lactobacillus sp. and Bifidobacterium minimum dominated. These three species are potential candidates for the development of a starter culture. Copyright © 2018 Elsevier Ltd. All rights reserved.

The effect of different phosphate ion concentrations and ph of the phosphate buffer on lipase bioproduction by rhizopus oligosporus

International Nuclear Information System (INIS)

Haq, I.; Ali, S.; Awan, U.F.; Javed, W.; Mirza, S.

2005-01-01

In the present investigation, we report the effect of phosphate ion concentration and different ph of the phosphate buffer (as diluent) on lipase bioproduction by Rhizopus oligosporus. For this purpose, solid state fermentation was employed. Different agricultural by-products such as wheat bran, rice husk, almond meal, soybean meal and sunflower meal were used as substrate. The maximum lipase activity (72.60 U/g) was observed with the almond meal. Addition of phosphate ions (K/sub 2/HPO/sub 4/) influenced the lipase production. The ph of the phosphate buffer (7.0) was found to be effective for higher yield of lipase. (author)

Pengaruh Variasi Waktu Fermentasi terhadap Kadar Laktosa, Lemak, Ph dan Keasaman pada Susu Sapi yang Difermentasi Menjadi Yogurt

OpenAIRE

Agustina, Yeni; Kartika, Rudi; Panggabean, Aman S

2015-01-01

Yogurt is a fermentation milk product with bacteria Streptococcus thermophillus and Lactobacillus bulgariccus which has been commonly used in the process of making yogurt. The purpose of this study was to determine the effect of fermentation on the levels of lactose, fat, pH, acidity in yogurt. Determination of lactose in volumetric according Gohr, fat content carried by the Gerber method, using a pH meter pH and acidity values using titration.

Influence of fermentation and cowpea steaming on some quality ...

African Journals Online (AJOL)

Fermentation and cowpea steaming can be used to improve the protein quality and quantity of fermented maize dough. In the production of maize-cowpea blends, it is important that the quality characteristics are evaluated to determine their functionality in the products. A 5x4x2x2 factorial experiment with cowpea level, ...

Dark fermentative biohydrogen production by mesophilic bacterial consortia isolated from riverbed sediments

Energy Technology Data Exchange (ETDEWEB)

Singh, Sneha; Sudhakaran, Anu K.; Sarma, Priyangshu Manab; Subudhi, Sanjukta; Mandal, Ajoy Kumar; Lal, Banwari [Environmental and Industrial Biotechnology Division, The Energy and Resources Institute (TERI), Habitat Place, Darbari Seth Block, Lodhi Road, New Delhi 110003 (India); Gandham, Ganesh [Hindustan Petroleum Corporation Limited, Mumbai Refinery, B. D. Patil Marg, Mahul, Mumbai 400074 (India)

2010-10-15

Dark fermentative bacterial strains were isolated from riverbed sediments and investigated for hydrogen production. A series of batch experiments were conducted to study the effect of pH, substrate concentration and temperature on hydrogen production from a selected bacterial consortium, TERI BH05. Batch experiments for fermentative conversion of sucrose, starch, glucose, fructose, and xylose indicated that TERI BH05 effectively utilized all the five sugars to produce fermentative hydrogen. Glucose was the most preferred carbon source indicating highest hydrogen yields of 22.3 mmol/L. Acetic and butyric acid were the major soluble metabolites detected. Investigation on optimization of pH, temperature, and substrate concentration revealed that TERI BH05 produced maximum hydrogen at 37 C, pH 6 with 8 g/L of glucose supplementation and maximum yield of hydrogen production observed was 2.0-2.3 mol H{sub 2}/mol glucose. Characterization of TERI BH05 revealed the presence of two different bacterial strains showing maximum homology to Clostridium butyricum and Clostridium bifermentans. (author)

Effects of Gamma Irradiation on Quality in the Processing of Low Salted and Fermented Shrimp

International Nuclear Information System (INIS)

Shin Myung-Gon; Lee Cherl-Ho

2000-01-01

Irradiation technology was applied to develop low salted and fermented shrimp that has better sensory quality and a longer shelf-life without any food additives. Different levels of salt (10, 15, and 20%, w/w) were added to the salted and fermented shrimp and the samples were irradiated at 0, 2.5, 5.0, 7.5, and 10.0 kGy with a gamma source (Co-60). Proximate composition, salinity, water activity (a), pH, total bacterial count, and general acceptance were analyzed during fermentation at 15 degrees after irradiation. The proximate analysis, salinity, and a were not affected by gamma irradiation during fermentation. However, pH and total bacteria, as well as sensory evaluation, were changed variously with processing conditions such as sodium chloride concentration and irradiation dose. The combinations of 15% salt concentration with 10 kGy irradiation dose and 20% with 5 kGy or above were effective for shelf-life enhancement of the salted and fermented shrimp by adequate suppression of microorganisms during fermentation at 15 degrees. The results showed that the sensory quality of the sample was maintained up to 10 weeks after fermentation. Therefore, it was considered that gamma irradiation was effective in processing low salted and fermented shrimp and extending their shelf-life without adding any food additives

[Transformation of baicalin and wogonoside through liquid fermentation with Bacillus natto].

Science.gov (United States)

Long, Hou-ning; Zhang, Shuo; Yao, Lei; Zhang, Min; Wang, Peng-jiao; Meng, Xiao-xia; Gao, Xiu; Zhang, Rong-ping

2015-12-01

This experiment aimed to explore and research the process of preparing baicalein and wogonin through liquid fermentation with Bacillus natto. Active enzymes of produced by B. natto was used for the biological transformation of baclin and wogonoside, in order to increase the content of the haicalein and wogonin in the scutellaria. With the content of the baicalein and wogonin as evaluating indexes, the effects of carbon source, nitrogen source, the types and suitable concentration of inorganic salt, medium pH, granularities of medical materials, liquid volume in flask, shaking speed, liquid-to-solid ratio, fermentation time on the fermentation process were studied. The optimal process conditions for liquid fermentation of scutellaria were 1.0% of peptone, 0.05% of NaCl, pH at 6, the granularities of medical materials of the scutellaria screened through 40-mesh sifter, 33% of liquid, shaker incubator speed at 200 r x min(-1), liquid-to-solid ratio of 5:1, temperature at 37 degrees C, fermentation for 6 days, baclin's conversion rate at 97.6% and wogonoside's conversion rate at 97% in the scutellaria. According to the verification test, the process was stable and feasible, and could provide data reference for the industrial production.

Heat and Mass Transfer Measurements for Tray-Fermented Fungal Products

Science.gov (United States)

Jou, R.-Y.; Lo, C.-T.

2011-01-01

In this study, heat and mass transfer in static tray fermentation, which is widely used in solid-state fermentation (SSF) to produce fungal products, such as enzymes or koji, is investigated. Specifically, kinetic models of transport phenomena in the whole-tray chamber are emphasized. The effects of temperature, moisture, and humidity on microbial growth in large-scale static tray fermentation are essential to scale-up SSF and achieve uniform fermentation. In addition, heat and mass transfer of static tray fermentation of Trichoderma fungi with two tray setups—traditional linen coverings and stacks in a temperature-humidity chamber is examined. In both these setups, the following factors of fermentation were measured: air velocity, air temperature, illumination, pH, carbon dioxide (CO2) concentration, and substrate temperature, and the effects of bed height, moisture of substrate, and relative humidity of air are studied. A thin (1 cm) bed at 28 °C and 95 % relative humidity is found to be optimum. Furthermore, mixing was essential for achieving uniform fermentation of Trichoderma fungi. This study has important applications in large-scale static tray fermentation of fungi.

Comparative behaviour of yeast strains for ethanolic fermentation of culled apple juice.

Science.gov (United States)

Modi, D R; Garg, S K; Johri, B N

1998-07-01

The culled apple juice contained (% w/v): nitrogen, 0.036; total sugars, 11.6 and was of pH 3.9. Saccharomyces cerevisiae NCIM 3284, Pichia kluyeri and Candida krusei produced more ethanol from culled apple juice at its optimum initial pH 4.5, whereas S. cerevisiae NCIM 3316 did so at pH 5.0. An increase in sugar concentration of apple juice from natural 11.6% to 20% exhibited enhanced ethanol production and improved fermentation efficiency of both the S. cerevisiae strains, whereas P. kluyveri and C. krusei produced high ethanol at 11.6% and 16.0% sugar levels, respectively. Urea was stimulatory for ethanol production as well as fermentation efficiency of the yeast strains under study.

Probiotic viability and storage stability of yogurts and fermented milks prepared with several mixtures of lactic acid bacteria.

Science.gov (United States)

Mani-López, E; Palou, E; López-Malo, A

2014-05-01

Currently, the food industry wants to expand the range of probiotic yogurts but each probiotic bacteria offers different and specific health benefits. Little information exists on the influence of probiotic strains on physicochemical properties and sensory characteristics of yogurts and fermented milks. Six probiotic yogurts or fermented milks and 1 control yogurt were prepared, and we evaluated several physicochemical properties (pH, titratable acidity, texture, color, and syneresis), microbial viability of starter cultures (Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus) and probiotics (Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus reuteri) during fermentation and storage (35 d at 5°C), as well as sensory preference among them. Decreases in pH (0.17 to 0.50 units) and increases in titratable acidity (0.09 to 0.29%) were observed during storage. Only the yogurt with S. thermophilus, L. delbrueckii ssp. bulgaricus, and L. reuteri differed in firmness. No differences in adhesiveness were determined among the tested yogurts, fermented milks, and the control. Syneresis was in the range of 45 to 58%. No changes in color during storage were observed and no color differences were detected among the evaluated fermented milk products. Counts of S. thermophilus decreased from 1.8 to 3.5 log during storage. Counts of L. delbrueckii ssp. bulgaricus also decreased in probiotic yogurts and varied from 30 to 50% of initial population. Probiotic bacteria also lost viability throughout storage, although the 3 probiotic fermented milks maintained counts ≥ 10(7)cfu/mL for 3 wk. Probiotic bacteria had variable viability in yogurts, maintaining counts of L. acidophilus ≥ 10(7) cfu/mL for 35 d, of L. casei for 7d, and of L. reuteri for 14 d. We found no significant sensory preference among the 6 probiotic yogurts and fermented milks or the control. However, the yogurt and fermented milk made with L. casei were better accepted. This

The γ-aminobutyric acid-producing ability under low pH conditions of lactic acid bacteria isolated from traditional fermented foods of Ishikawa Prefecture, Japan, with a strong ability to produce ACE-inhibitory peptides

Directory of Open Access Journals (Sweden)

Florin Barla

2016-06-01

Full Text Available Many traditional fermented products are onsumed in Ishikawa Prefecture, Japan, such as kaburazushi, narezushi, konkazuke, and ishiru. Various kinds of lactic acid bacteria (LAB are associated with their fermentation, however, characterization of LAB has not yet been elucidated in detail. In this study, we evaluated 53 isolates of LAB from various traditional fermented foods by taxonomic classification at the species level by analyzing the 16S ribosomal RNA gene (rDNA sequences and carbohydrate assimilation abilities. We screened isolates that exhibited high angiotensin-converting enzyme (ACE inhibitory activities in skim milk or soy protein media and produced high γ-aminobutyric acid (GABA concentrations in culture supernatants when grown in de Man Rogosa Sharpe broth in the presence of 1% (w/v glutamic acid. The results revealed that 10 isolates, i.e., Lactobacillus buchneri (2 isolates, Lactobacillus brevis (6 isolates, and Weissella hellenica (2 isolates had a high GABA-producing ability of >500 mg/100 ml after 72 h of incubation at 35 °C. The ACE inhibitory activity of the whey cultured with milk protein by using L. brevis (3 isolates, L. buchneri (2 isolates, and W. hellenica (2 isolates was stronger than that of all whey cultured with soy protein media, and these IC50 were < 1 mg protein/ml. Three of 10 isolates had high GABA-producing activities at pH 3, suggesting that they could be powerful candidates for use in the fermentation of food materials having low pH.

Effect of Crude Protein Levels in Concentrate and Concentrate Levels in Diet on Fermentation

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Dinh Van Dung

2014-06-01

Full Text Available The effect of concentrate mixtures with crude protein (CP levels 10%, 13%, 16%, and 19% and diets with roughage to concentrate ratios 80:20, 60:40, 40:60, and 20:80 (w/w were determined on dry matter (DM and organic matter (OM digestibility, and fermentation metabolites using an in vitro fermentation technique. In vitro fermented attributes were measured after 4, 24, and 48 h of incubation respectively. The digestibility of DM and OM, and total volatile fatty acid (VFA increased whereas pH decreased with the increased amount of concentrate in the diet (p<0.001, however CP levels of concentrate did not have any influence on these attributes. Gas production reduced with increased CP levels, while it increased with increasing concentrate levels. Ammonia nitrogen (NH3-N concentration and microbial CP production increased significantly (p<0.05 by increasing CP levels and with increasing concentrate levels in diet as well, however, no significant difference was found between 16% and 19% CP levels. Therefore, 16% CP in concentrate and increasing proportion of concentrate up to 80% in diet all had improved digestibility of DM and organic matter, and higher microbial protein production, with improved fermentation characteristics.

Batch fermentation of whey ultra filtrate by Lactobacillus helveticus for lactic acid production

Energy Technology Data Exchange (ETDEWEB)

Roy, D; Goulet, J; Le Duy, Q

1986-06-01

Cheese whey ultrafiltrate (WU) was used as the carbon source for the production of lactic acid by batch fermentation with Lactobacillus helveticus strain milano. The fermentation was conducted in a 400 ml fermentor at an agitation rate of 200 revolutions per minute and under conditions of controlled temperature (42 degrees C) and pH. In the whey ultrafiltrate-corn steep liquor (WU-CSL) medium, the optimal pH for fermentation was 5.9. Inoculum propagated in skim milk (SM) medium or in lactose synthetic (LS) medium resulted in the best performance in fermentation (in terms of growth, lactic acid production, lactic acid yield and maximum productivity of lactic acid), as compared to that propagated in glucose synthetic (GS) medium. The yeast extract ultrafiltrate (YEU) used as the nitrogen/growth factor source in the WU medium at 1.5% (w/v) gave the highest maximum productivity of lactic acid of 2.70 g/l-h, as compared to the CSL and the tryptone ultrafiltrate (TU). 27 references.

Effect of Fermentation Parameters on Extra Cellular Tannase Production by Lactobacillus plantarum MTCC 1407

OpenAIRE

Kannan Natarajan; Aravindan Rajendran

2009-01-01

Lactobacillus plantarum MTCC 1407 represents a valuable source of an economically attractive stable long-life tannase with potential for application in various industries. The effect of fermentation parameters such as pH, temperature and agitation speed on the growth of biomass and production of tannase using liquid medium were determined at the end of fermentation period. The optimum values of pH, reaction temperature and agitation speed for tannase activity were 6.0, 30 °C and 125 rpm respe...

Shuidouchi (Fermented Soybean Fermented in Different Vessels Attenuates HCl/Ethanol-Induced Gastric Mucosal Injury

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Huayi Suo

2015-11-01

Full Text Available Shuidouchi (Natto is a fermented soy product showing in vivo gastric injury preventive effects. The treatment effects of Shuidouchi fermented in different vessels on HCl/ethanol-induced gastric mucosal injury mice through their antioxidant effect was determined. Shuidouchi contained isoflavones (daidzein and genistein, and GVFS (glass vessel fermented Shuidouchi had the highest isoflavone levels among Shuidouchi samples fermented in different vessels. After treatment with GVFS, the gastric mucosal injury was reduced as compared to the control mice. The gastric secretion volume (0.47 mL and pH of gastric juice (3.1 of GVFS treated gastric mucosal injury mice were close to those of ranitidine-treated mice and normal mice. Shuidouchi could decrease serum motilin (MTL, gastrin (Gas level and increase somatostatin (SS, vasoactive intestinal peptide (VIP level, and GVFS showed the strongest effects. GVFS showed lower IL-6, IL-12, TNF-α and IFN-γ cytokine levels than other vessel fermented Shuidouchi samples, and these levels were higher than those of ranitidine-treated mice and normal mice. GVFS also had higher superoxide dismutase (SOD, nitric oxide (NO and malonaldehyde (MDA contents in gastric tissues than other Shuidouchi samples. Shuidouchi could raise IκB-α, EGF, EGFR, nNOS, eNOS, Mn-SOD, Gu/Zn-SOD, CAT mRNA expressions and reduce NF-κB, COX-2, iNOS expressions as compared to the control mice. GVFS showed the best treatment effects for gastric mucosal injuries, suggesting that glass vessels could be used for Shuidouchi fermentation in functional food manufacturing.

AKTIVITAS PROTEOLITIK BAKTERI ASAM LAKTAT DALAM FERMENTASI SUSU KEDELAI [Proteolytic Activities of Lactic Acid Bacteria in Fermentation of Soymilk

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Yusmarini1,2*

2010-12-01

Full Text Available Some lactic acid bacteria (LAB strains had been isolated from spontaneously fermented soymilk which have proteolytic system. The purpose of this research was to study ability of isolates in fermentation of soymilk. The changes in bacterial growth, pH, titrable acidity, and proteolytic activities during fermentation were examined. Isolates of Lactobacillus plantarum 1 R.1.3.2; L. plantarum 1 R.11.1.2 and L. acidophilus FNCC 0051 (as a control were capable growing in soymilk. The results indicated that initial pH of soymilk was 6,6 and decreased to 4,6 after fermentation and titrable acidity of 0.11 increased to 0.34 after fermentation. The proteolytic activities were 0.352 U/ml – 0.468 U/ml. The electrophoretic pattern of the proteins showed changes during fermentation of soymilk.

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.

Fermentation of cereals - Influence on digestibility of nutrients in growing pigs

DEFF Research Database (Denmark)

Jørgensen, Henry; Sholly, Danielle; Pedersen, Anni Øyan

2010-01-01

) at a ratio of 1:2.75 (wt/wt). Four experimental diets consisting of either dry or fermented barley or wheat, supplemented with a protein mixture (not fermented) were formulated to contain recommended levels of nutrients. Eight pigs from two litters were surgically fitted with a T-cannula anterior to the ileo......-cecal junction and fed one of the four experimental diets according to a repeated 4 × 4 Latin-square design. The fermentation process was followed by measuring the changes in the major nutrients, microbial composition and organic acid concentrations. Fermentation caused a reduced concentration of carbohydrates...

Assessing the influence of reactor system design criteria on the performance of model colon fermentation units.

Science.gov (United States)

Moorthy, Arun S; Eberl, Hermann J

2014-04-01

Fermentation reactor systems are a key platform in studying intestinal microflora, specifically with respect to questions surrounding the effects of diet. In this study, we develop computational representations of colon fermentation reactor systems as a way to assess the influence of three design elements (number of reactors, emptying mechanism, and inclusion of microbial immobilization) on three performance measures (total biomass density, biomass composition, and fibre digestion efficiency) using a fractional-factorial experimental design. It was determined that the choice of emptying mechanism showed no effect on any of the performance measures. Additionally, it was determined that none of the design criteria had any measurable effect on reactor performance with respect to biomass composition. It is recommended that model fermentation systems used in the experimenting of dietary effects on intestinal biomass composition be streamlined to only include necessary system design complexities, as the measured performance is not benefited by the addition of microbial immobilization mechanisms or semi-continuous emptying scheme. Additionally, the added complexities significantly increase computational time during simulation experiments. It was also noted that the same factorial experiment could be directly adapted using in vitro colon fermentation systems. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Investigating the influence of pH, temperature and agitation speed on yellow pigment production by Penicillium aculeatum ATCC 10409.

Science.gov (United States)

Afshari, Majid; Shahidi, Fakhri; Mortazavi, Seyed Ali; Tabatabai, Farideh; Es'haghi, Zarin

2015-01-01

In this study, the combined effect of pH, temperature and agitation speed on yellow pigment production and mycelial growth of Penicillium aculeatum ATCC 10409 was investigated in whey media. Different pH levels (5, 6.5 and 8), temperatures (25, 30 and 35°C) and agitation speed levels (100 and 150 rpm) were tested to determine the best conditions to produce a fungal yellow pigment under submerged fermentation. The best production of yellow pigment (1.38 g/L) was obtained with a pH value of 6.5, a temperature of 30°C and an agitation speed of 150 rpm. In contrast, the maximal biomass concentration (11.12 g/L) was obtained at pH value of 8, a temperature of 30°C and an agitation speed of 100 rpm. These results demonstrated that biomass and yellow pigment production were not directly associated. The identification of the structure of unknown P. aculeatum yellow pigment was detected using UV absorption spectrum and FT-IR spectroscopy.

The Effect of Fungicide Residues and Yeast Assimilable Nitrogen on Fermentation Kinetics and H2S Production during Cider Fermentation

OpenAIRE

Boudreau IV, Thomas Francis

2016-01-01

The Virginia cider industry has grown rapidly in the past decade, and demands research-based recommendations for cider fermentation. This study evaluated relationships between the unique chemistry of apples and production of hydrogen sulfide (H2S) in cider fermentations. Yeast assimilable nitrogen (YAN) concentration and composition and residual fungicides influence H2S production by yeast during fermentation, but these factors have to date only been studied in wine grape fermentations. This ...

Characteristics of Saccharomyces cerevisiae yeasts exhibiting rough colonies and pseudohyphal morphology with respect to alcoholic fermentation.

Science.gov (United States)

Reis, Vanda Renata; Bassi, Ana Paula Guarnieri; da Silva, Jessica Carolina Gomes; Ceccato-Antonini, Sandra Regina

2013-12-01

Among the native yeasts found in alcoholic fermentation, rough colonies associated with pseudohyphal morphology belonging to the species Saccharomyces cerevisiae are very common and undesirable during the process. The aim of this work was to perform morphological and physiological characterisations of S. cerevisiae strains that exhibited rough and smooth colonies in an attempt to identify alternatives that could contribute to the management of rough colony yeasts in alcoholic fermentation. Characterisation tests for invasiveness in Agar medium, killer activity, flocculation and fermentative capacity were performed on 22 strains (11 rough and 11 smooth colonies). The effects of acid treatment at different pH values on the growth of two strains ("52"--rough and "PE-02"--smooth) as well as batch fermentation tests with cell recycling and acid treatment of the cells were also evaluated. Invasiveness in YPD Agar medium occurred at low frequency; ten of eleven rough yeasts exhibited flocculation; none of the strains showed killer activity; and the rough strains presented lower and slower fermentative capacities compared to the smooth strains in a 48-h cycle in a batch system with sugar cane juice. The growth of the rough strain was severely affected by the acid treatment at pH values of 1.0 and 1.5; however, the growth of the smooth strain was not affected. The fermentative efficiency in mixed fermentation (smooth and rough strains in the same cell mass proportion) did not differ from the efficiency obtained with the smooth strain alone, most likely because the acid treatment was conducted at pH 1.5 in a batch cell-recycle test. A fermentative efficiency as low as 60% was observed with the rough colony alone.

Fermentation of African kale (Brassica carinata) using L. plantarum BFE 5092 and L. fermentum BFE 6620 starter strains.

Science.gov (United States)

Oguntoyinbo, Folarin A; Cho, Gyu-Sung; Trierweiler, Bernhard; Kabisch, Jan; Rösch, Niels; Neve, Horst; Bockelmann, Wilhelm; Frommherz, Lara; Nielsen, Dennis S; Krych, Lukasz; Franz, Charles M A P

2016-12-05

Vegetables produced in Africa are sources of much needed micronutrients and fermentation is one way to enhance the shelf life of these perishable products. To prevent post-harvest losses and preserve African leafy vegetables, Lactobacillus plantarum BFE 5092 and Lactobacillus fermentum BFE 6620 starter strains were investigated for their application in fermentation of African kale (Brassica carinata) leaves. They were inoculated at 1×10 7 cfu/ml and grew to a maximum level of 10 8 cfu/ml during 24h submerged fermentation. The strains utilized simple sugars (i.e., glucose, fructose, and sucrose) in the kale to quickly reduce the pH from pH6.0 to pH3.6 within 24h. The strains continued to produce both d and l lactic acid up to 144h, reaching a maximum concentration of 4.0g/l. Fermentations with pathogens inoculated at 10 4 cfu/ml showed that the quick growth of the starters inhibited the growth of Listeria monocytogenes and Salmonella Enteritidis, as well as other enterobacteria. Denaturing gradient gel electrophoresis and 16S rRNA gene (V3-V4-region) amplicon sequencing showed that in the spontaneous fermentations a microbial succession took place, though with marked differences in biodiversity from fermentation to fermentation. The fermentations inoculated with starters however were clearly dominated by both the inoculated strains throughout the fermentations. RAPD-PCR fingerprinting showed that the strains established themselves at approx. equal proportions. Although vitamins C, B 1 and B 2 decreased during the fermentation, the final level of vitamin C in the product was an appreciable concentration of 35mg/100g. In conclusion, controlled fermentation of kale offers a promising avenue to prevent spoilage and improve the shelf life and safety. Copyright © 2016 Elsevier B.V. All rights reserved.

Technological properties of Lactobacillus plantarum strains isolated from grape must fermentation.

Science.gov (United States)

Berbegal, Carmen; Peña, Nuria; Russo, Pasquale; Grieco, Francesco; Pardo, Isabel; Ferrer, Sergi; Spano, Giuseppe; Capozzi, Vittorio

2016-08-01

Malolactic fermentation (MLF) is a secondary fermentation in wine that usually takes place during or at the end of alcoholic fermentation. Lactobacillus plantarum is able to conduct MLF (particularly under high pH conditions and in co-inoculation with yeasts), and some strains are commercially used as MLF starter cultures. Recent evidences suggest a further use of selected L. plantarum strains for the pre-alcoholic acidification of grape must. In this study, we have carried out an integrated (molecular, technological, and biotechnological) characterization of L. plantarum strains isolated from Apulian wines in order to combine the two protechnological features (MLF performances and must acidification aptitudes). Several parameters such as sugar, pH and ethanol tolerance, resistance to lyophilisation and behaviour in grape must were evaluated. Moreover, the expression of stress gene markers was investigated and was linked to the ability of L. plantarum strains to grow and perform MLF. Co-inoculation of Saccharomyces cerevisiae and L. plantarum in grape must improves the bacterial adaptation to harsh conditions of wine and reduced total fermentation time. For the first time, we applied a polyphasic approach for the characterization of L. plantarum in reason of the MLF performances. The proposed procedure can be generalized as a standard method for the selection of bacterial resources for the design of MLF starter cultures tailored for high pH must. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fermentation of African kale (Brassica carinata) using L. plantarum BFE 5092 and L. fermentum BFE 6620 starter strains

DEFF Research Database (Denmark)

Oguntoyinbo, Folarin A; Cho, Gyu-Sung; Trierweiler, Bernhard

2016-01-01

Vegetables produced in Africa are sources of much needed micronutrients and fermentation is one way to enhance the shelf life of these perishable products. To prevent post-harvest losses and preserve African leafy vegetables, Lactobacillus plantarum BFE 5092 and Lactobacillus fermentum BFE 6620...... starter strains were investigated for their application in fermentation of African kale (Brassica carinata) leaves. They were inoculated at 1×10(7)cfu/ml and grew to a maximum level of 10(8)cfu/ml during 24h submerged fermentation. The strains utilized simple sugars (i.e., glucose, fructose, and sucrose......) in the kale to quickly reduce the pH from pH6.0 to pH3.6 within 24h. The strains continued to produce both d and l lactic acid up to 144h, reaching a maximum concentration of 4.0g/l. Fermentations with pathogens inoculated at 10(4)cfu/ml showed that the quick growth of the starters inhibited the growth...

Non-Alcoholic Beverages from Fermented Cereals with Increased Oligosaccharide Content

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Grazina Juodeikiene

2016-01-01

Full Text Available The aim of this study is to develop a new technology for making traditional Lithuanian non-alcoholic beverage kvass from fermented cereals by extending the spectrum of raw materials (extruded rye and applying new biotechnological resources (xylanolytic enzymes and lactic acid bacteria (LAB to improve its functional properties. Arabinoxylans in extruded rye were very efficiently hydrolysed into oligosaccharides by xylanolytic complex Ceremix Plus MG. Using Ceremix Plus MG and LAB fermentation, the yield of arabinoxylooligosaccharides and xylooligosaccharides in beverage was increased to 300 and 1100 mg/L, respectively. Beverages fermented by LAB had lower pH values and ethanol volume fraction compared to the yeast-fermented beverage. The acceptability of the beverage fermented by Lactobacillus sakei was higher than of Pediococcus pentosaceus- or yeast-fermented beverages and similar to the acceptability of commercial kvass made from malt extract. The results showed that extruded rye, xylanolytic enzymes and LAB can be used for production of novel and safe high-value non-alcoholic beverages.

Xylitol from rice husks by acid hydrolysis and Candida yeast fermentation

Directory of Open Access Journals (Sweden)

Magale K. D. Rambo

2013-01-01

Full Text Available An investigation was conducted into the production of xylose by acid hydrolysis of rice husks and its subsequent bioconversion to xylitol. The parameters were optimised using the response surface methodology. The fermentation stage took place with the aid of the yeast species Candida guilliermondii and Candida tropicalis. An evaluation of the influence of several biomass pre-treatments was also performed. The effects of the acid concentration and hydrolysate pH on xylitol global yield were also assessed, and the highest yield of xylitol was 64.0% (w/w. The main products, xylose and xylitol, were identified and quantified by means of liquid chromatography.

Hydrocarbons by fermenting the juice of the Jerusalem artichoke

Energy Technology Data Exchange (ETDEWEB)

Joud, F R

1976-02-13

The artichoke juice containing nonfermentable insulins is acidified to pH 3- and heated at 95/sup 0/ for 30 to 40 minutes to hydrolyze the insulins into fermentable sugars which are then fermented to ethanol. The ethanol is dried and reacted with H/sub 2/SO/sub 4/ to form C/sub 2/H/sub 4/ which is treated at 300/sup 0/ under pressure with a powdered Ni catalyst to form alkanes, alkenes, and alkynes.

Enzymatic Modification of Corn Starch Influences Human Fecal Fermentation Profiles.

Science.gov (United States)

Dura, Angela; Rose, Devin J; Rosell, Cristina M

2017-06-14

Enzymatically modified starches have been widely used in food applications to develop new products, but information regarding digestion and fecal fermentation of these products is sparse. The objective of this study was to determine the fermentation properties of corn starch modified with α-amylase, amyloglucosidase, or cyclodextrin glycosyltransferase and the possible role of hydrolysis products. Samples differed in their digestibility and availability to be fermented by the microbiota, resulting in differences in microbial metabolites produced during in vitro fermentation. The presence or absence of hydrolysis products and gelatinization affected starch composition and subsequent metabolite production by the microbiota. Amyloglucosidase-treated starch led to the greatest production of short- and branched-chain fatty acid production by the microbiota. Results from this study could be taken into consideration to confirm the possible nutritional claims and potential health benefits of these starches as raw ingredients for food development.

Effect of micro-organism and particle size on fermentation of ...

African Journals Online (AJOL)

Aziwo Niba

2013-06-26

Jun 26, 2013 ... Full Length Research Paper. Effect of micro-organism and particle size on ... fermentation for pH, sugar and organic acids analysis. Significant reductions in the pH of maize and sorghum .... Raw sorghum was milled in a hammer mill to pass through a 3 mm screen while equal quantities of raw maize were ...

Influence of the Dentinal Wall on the pH of Sodium Hypochlorite during Root Canal Irrigation

NARCIS (Netherlands)

Macedo, Ricardo Gomes; Herrero, Noemi Pascual; Wesselink, Paul; Versluis, Michel; van der Sluis, Luc

Introduction: The purpose of this study was to evaluate the influence of dentin on the pH levels of different concentrations of sodium hypochlorite (NaOCl) solutions over time and to evaluate if preconditioning of dentin with 17% EDTA or agitation of the NaOCl solution influences these pH levels.

Electricity generation from fermented primary sludge using single-chamber air-cathode microbial fuel cells

KAUST Repository

Yang, Fei; Ren, Lijiao; Pu, Yuepu; Logan, Bruce E.

2013-01-01

Single-chamber air-cathode microbial fuel cells (MFCs) were used to generate electricity from fermented primary sludge. Fermentation (30°C, 9days) decreased total suspended solids (26.1-16.5g/L), volatile suspended solids (24.1-15.3g/L) and pH (5

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...

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.)

Manufacture of a beverage from cheese whey using a "tea fungus" fermentation.

Science.gov (United States)

Belloso-Morales, Genette; Hernández-Sánchez, Humberto

2003-01-01

Kombucha is a sour beverage reported to have potential health effects prepared from the fermentation of black tea and sugar with a "tea fungus", a symbiotic culture of acetic acid bacteria and yeasts. Although black tea is the preferred substrate for Kombucha fermentation, other beverages have also been tested as substrates with fair results. Cheese whey is a by-product with a good amount of fermentable lactose that has been used before in the production of beverages, so the objective of this study was to test three types of whey (fresh sweet, fresh acid and reconstituted sweet) in the elaboration of a fermented beverage using a kombucha culture as inoculum. The isolation and identification of bacteria and yeasts from the fermented tea and wheys was done along with the study of the rates of change in sugar consumption, acid production and pH decrease. Several species of acetic acid bacteria (Acetobacter aceti subsp. aceti, Gluconobacter oxydans subsp. industrius, subsp. oxydans and Gluconoacetobacter xylinus) were isolated from the different kombuchas along with the yeasts Saccharomyces cerevisiae, Kluyveromyces marxianus, and Brettanomyces bruxelensis. The main metabolic products in the fermented wheys included ethanol, lactic and acetic acids. A good growth was obtained in both sweet wheys in which a pH of 3.3 and a total acid content (mainly lactic and acetic acids) of 0.07 mol/l was reached after 96 h. The sweet whey fermented beverages contained a relatively low lactose concentration (< 12 g/l). The final ethanol content was low (5 g/l) in all the fermented wheys. The whey products were strongly sour and salty non sparkling beverages.

Etude microbiologique des feuilles fermentées de manioc: "Ntoba Mbodi"

Directory of Open Access Journals (Sweden)

Bouanga Kalou, G.

2003-01-01

Full Text Available Microbiological Study of "Ntoba-Mbodi", Fermented Cassava Leaves. Some families and small processing units proceed by way of fermentation of the cassava leaves to make "ntoba mbodi", a dish with a particular taste and flavor. The fermentation process lastes 4 days and after that the product undergoes significant alteration. During fermentation, about 70% of the cyanogenic glucosides are eliminated compared to 82 to 94% by blanching, vapor cooking or sun drying. Thus fermentation can be considered as good in eliminating cyanide as these other methods. Contrary to other plant material whose fermentation leads to an increase in acidity, fermentation of cassava leaves leads to alkalinization, with the pH rising from 6.2 to 8.9. Microbiological analyses of the fermented cassava leaves reveal the unusual presence of Micrococcus varians, Bacillus macerans, Bacillus subtilis, Staphylococcus sciuri and Staphylococcus xylosus among the other usual microorganisms; however yeasts and Leuconostoc strains are not present. Among this micro-organisms, Bacillus macerans, Bacillus subtilis, Bacillus cereus, Staphylococcus xylosus and Erwinia spp. play an important role in with their polysaccharolytic enzymes.

Prokaryotic community composition in alkaline-fermented skate (Raja pulchra).

Science.gov (United States)

Jang, Gwang Il; Kim, Gahee; Hwang, Chung Yeon; Cho, Byung Cheol

2017-02-01

Prokaryotes were extracted from skates and fermented skates purchased from fish markets and a local manufacturer in South Korea. The prokaryotic community composition of skates and fermented skates was investigated using 16S rRNA pyrosequencing. The ranges for pH and salinity of the grinded tissue extract from fermented skates were 8.4-8.9 and 1.6-6.6%, respectively. Urea and ammonia concentrations were markedly low and high, respectively, in fermented skates compared to skates. Species richness was increased in fermented skates compared to skates. Dominant and predominant bacterial groups present in the fermented skates belonged to the phylum Firmicutes, whereas those in skates belonged to Gammaproteobacteria. The major taxa found in Firmicutes were Atopostipes (Carnobacteriaceae, Lactobacillales) and/or Tissierella (Tissierellaceae, Tissierellales). A combination of RT-PCR and pyrosequencing for active bacterial composition showed that the dominant taxa i.e., Atopostipes and Tissierella, were active in fermented skate. Those dominant taxa are possibly marine lactic acid bacteria. Marine bacteria of the taxa Lactobacillales and/or Clostridia seem to be important in alkaline fermentation of skates. Copyright © 2016 Elsevier Ltd. All rights reserved.

Volatile compounds formation in alcoholic fermentation from grapes collected at 2 maturation stages: Influence of nitrogen compounds and grape variety

OpenAIRE

Martínez-Gil, A. M.; Garde-Cerdán, Teresa; Lorenzo, Cándida; Félix Lara, J.; Pardo, F.; Rosario Salinas, M.

2012-01-01

The aim of this work was to study the influence of nitrogen compounds on the formation of volatile compounds during the alcoholic fermentation carried out with 4 nonaromatic grape varieties collected at 2 different maturation stages. To do this, Monastrell, Merlot, Syrah, and Petit Verdot grapes were collected 1 wk before harvest and at harvest. Then, the musts were inoculated with the same Saccharomyces cerevisiae yeast strain and were fermented in the same winemaking conditions. Amino acids...

Molecular identification and physiological characterization of yeasts, lactic acid bacteria and acetic acid bacteria isolated from heap and box cocoa bean fermentations in West Africa.

Science.gov (United States)

Visintin, Simonetta; Alessandria, Valentina; Valente, Antonio; Dolci, Paola; Cocolin, Luca

2016-01-04

Yeast, lactic acid bacteria (LAB) and acetic acid bacteria (AAB) populations, isolated from cocoa bean heap and box fermentations in West Africa, have been investigated. The fermentation dynamicswere determined by viable counts, and 106 yeasts, 105 LAB and 82 AAB isolateswere identified by means of rep-PCR grouping and sequencing of the rRNA genes. During the box fermentations, the most abundant species were Saccharomyces cerevisiae, Candida ethanolica, Lactobacillus fermentum, Lactobacillus plantarum, Acetobacter pasteurianus and Acetobacter syzygii, while S. cerevisiae, Schizosaccharomyces pombe, Hanseniaspora guilliermondii, Pichia manshurica, C. ethanolica, Hanseniaspora uvarum, Lb. fermentum, Lb. plantarum, A. pasteurianus and Acetobacter lovaniensis were identified in the heap fermentations. Furthermore, the most abundant species were molecularly characterized by analyzing the rep-PCR profiles. Strains grouped according to the type of fermentations and their progression during the transformation process were also highlighted. The yeast, LAB and AAB isolates were physiologically characterized to determine their ability to grow at different temperatures, as well as at different pH, and ethanol concentrations, tolerance to osmotic stress, and lactic acid and acetic acid inhibition. Temperatures of 45 °C, a pH of 2.5 to 3.5, 12% (v/v) ethanol and high concentrations of lactic and acetic acid have a significant influence on the growth of yeasts, LAB and AAB. Finally, the yeastswere screened for enzymatic activity, and the S. cerevisiae, H. guilliermondii, H. uvarumand C. ethanolica species were shown to possess several enzymes that may impact the quality of the final product.

What is alcoholic fermentation? A study about the alcoholic fermentation conception through the history

Directory of Open Access Journals (Sweden)

C.A. F. Cardoso

2004-05-01

Full Text Available This work shows the historical development of the alcoholic fermentation conception, based on expe-rimental results obtained from European scientists, from Renascence to the beginning of 20th century(1930. From this, ve concepts were identied for the phenomenon: putrefactive, spiritual, chemical,biological and biochemical. The current conception of alcoholic fermentation was also evaluated. Forthis proposal, three groups of teachers were interviewed through the question? What is alcoholicfermentation? The P group (pilot, n=12 made of professionals that teach on secondary and highschools, group A composed of PhDs from the Center of Technology Education - NUTES (n=9 andgroup B from Department of Medical Biochemistry (called group B, n=41 both of Federal Universityof Rio de Janeiro, respectively. Key words associated with the fermentative process were identiedidentify in the interviewees answers. The group A components mentioned only six key words andpointed out the alcoholic fermentation products. Dierently, subjects from P and B groups cited ahigher number and also more unusual key words (n = 9 and 12, respectively. We also analyzedtheir answers throughout fermentative descriptive words (sugar, alcohol, carbon dioxide, anaerobic,yeast and ATP. These words were established after an evaluation of alcoholic fermentation conceptstated in the Biology/Biochemistry books most adopted in high schools and Universities. Our analysisshowed that group A used only three descriptive words (sugar, alcohol and yeast while componentsof group B used all the selected descriptive words. However, only one interviewee used all the sixwords together. From this analysis, we proposed that the chemical concept of alcoholic fermentationprevailed on the other concepts found on the historical research (spiritual, putrefactive, biological ebiochemical.

A novel process for volatile fatty acids production from syngas by integrating with mesophilic alkaline fermentation of waste activated sludge

DEFF Research Database (Denmark)

Rao, Yue; Wan, Jingjing; Liu, Yafeng

2018-01-01

The present study proposed and demonstrated a novel process for the bioconversion of syngas (mainly CO and H2) to valuable volatile fatty acids (VFA) by integrating with mesophilic alkaline fermentation of waste activated sludge (WAS). The results showed that although pH 9 was suitable for VFA...... to the mesophilic alkaline fermentation of WAS at pH 10 not only resulted in the enrichment of some known bacteria related with syngas conversion, but also changed the microbial community compositions for the fermentation of WAS....

Chemical properties and colors of fermenting materials in salmon fish sauce production

Directory of Open Access Journals (Sweden)

Mitsutoshi Nakano

2018-02-01

Full Text Available This data article reports the chemical properties (moisture, pH, salinity, and soluble solid content and colors of fermenting materials in salmon fish sauce products. The fish sauce was produced by mixing salt with differing proportions of raw salmon materials and fermenting for three months; the salmon materials comprised flesh, viscera, an inedible portion, and soft roe. Chemical properties and colors of the unrefined fish sauce (moromi, and the refined fish sauce, were analyzed at one, two, and three months following the start of fermentation. Data determined for all products are provided in table format. Keywords: Fish sauce, Chum salmon, Fermentation, Chemical properties, Color

Influence of aeration in the fermentative activity of Kloeckera apiculata during fermentation of apple juice; Influencia de la aireacion en la actividad fermentativa de Kloeckera apiculata durante la fermentacion de jugo de manzana

Energy Technology Data Exchange (ETDEWEB)

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

2012-07-01

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.

Effect of spices commercial mixture with GDL on the quality of fermented dry-cured sausages

Directory of Open Access Journals (Sweden)

Miroslav Kročko

2016-06-01

Full Text Available The main fermented meat products are fermented sausages in which lactic acid bacteria (LAB are the essential agents of the ripening process. Their application as starter organisms ensures the dominance of the starter during the whole ripening process. However, when no starter cultures are used, direct addition of acids like a glucono-delta-lactone (GdL is preferred. The goal of this study was to determine the influence of commercial spices mixtur (containing GdL on selected technological parameters of fermented dry-cured sausages - Danube sausage in comparison with currently available conventional spices. Comparison was evaluated also with addition of starter cultures. Determinations of technological (value of pH, water activity, color and microbiological properties (count of Lactobacillus spp., Enterobacteriaceae family, yeasts and moulds were realized after 24 hours, 5 and 30 days. The sensory analysis of sausages was carried out after 30 days of ripening process. In sausages with the addition of commercial spice mixture in combination with starter culture were determined the lowest values of pH and aw at the end of ripening process (30 days. Bacteria of Enterobacteriaceae family were occurred in the samples with the addition of currently available conventional spices at the beginning of ripening, but after 5 days of ripening were bacteria of this family not detected. The counts of yeasts in analyzed samples were not detected. Counts of LAB at the end of ripening proccess (30 days were lower in coparison with result obtained after 5 days; however their count was comparable with count determined at the beginig of the ripening. Our results show, that the combination of starter culture and commercial spice mixture containig GdL may cause excesive sour taste and sensory defect of dry fermented meat products.

Challenges in industrial fermentation technology research

DEFF Research Database (Denmark)

Formenti, Luca Riccardo; Nørregaard, Anders; Bolic, Andrijana

2014-01-01

Industrial fermentation processes are increasingly popular, and are considered an important technological asset for reducing our dependence on chemicals and products produced from fossil fuels. However, despite their increasing popularity, fermentation processes have not yet reached the same...... engineering challenges: scaling up and scaling down fermentation processes, the influence of morphology on broth rheology and mass transfer, and establishing novel sensors to measure and control insightful process parameters. The greatest emphasis is on the challenges posed by filamentous fungi, because...

Antifungal effect of kefir fermented milk and shelf life improvement of corn arepas.

Science.gov (United States)

Gamba, Raúl Ricardo; Caro, Carlos Andrés; Martínez, Olga Lucía; Moretti, Ana Florencia; Giannuzzi, Leda; De Antoni, Graciela Liliana; León Peláez, Angela

2016-10-17

Fungal contamination negatively affects the production of cereal foods such as arepa loaf, an ancient corn bread consumed daily in several countries of Latin-America. Chemical preservatives such as potassium sorbate are applied in order to improve the arepa's shelf life and to reduce the health risks. The use of natural preservatives such as natural fermented products in food commodities is a common demand among the consumers. Kefir is a milk fermented beverage obtained by fermentation of kefir grains. Its antibacterial and probiotic activity has been exhaustively demonstrated. Our objectives were to determine the antifungal effect of kefir fermented milk on Aspergillus flavus AFUNL5 in vitro and to study if the addition of kefir fermented milk to arepas could produce shelf life improvement. We determined the antifungal effect on solid medium of kefir cell-free supernatants (CFS) obtained under different fermentation conditions. Additionally, we compared the antifungal effect of kefir CFS with that obtained with unfermented milk artificially acidified with lactic plus acetic acids (lactic and acetic acids at the same concentration determined in kefir CFS) or with hydrochloric acid. Finally, kefir was added to the corn products either in the loaf recipe (kefir-baked arepas) or sprayed onto the baked-loaf surface (kefir-sprayed arepas). The loaves' resistance to natural and artificial fungal contamination and their organoleptic profiles were studied. The highest fungal inhibition on solid medium was achieved with kefir CFS produced by kefir grains CIDCA AGK1 at 100 g/L, incubated at 30 °C and fermented until pH 3.3. Other CFS obtained from different fermentation conditions achieved less antifungal activity than that mentioned above. However, CFS of milk fermented with kefir grains, until pH 4.5 caused an increase of growth rates. Additionally, CFS produced by kefir grains CIDCA AGK1 at 100 g/L, incubated at 30 °C and fermented until pH 3.3 achieved higher

Yield and cold storage of Trichoderma conidia is influenced by substrate pH and storage temperature.

Science.gov (United States)

Steyaert, Johanna M; Chomic, Anastasia; Nieto-Jacobo, Maria; Mendoza-Mendoza, Artemio; Hay, Amanda J; Braithwaite, Mark; Stewart, Alison

2017-05-01

In this study we examined the influence of the ambient pH during morphogenesis on conidial yield of Trichoderma sp. "atroviride B" LU132 and T. hamatum LU593 and storage at low temperatures. The ambient pH of the growth media had a dramatic influence on the level of Trichoderma conidiation and this was dependent on the strain and growth media. On malt-extract agar, LU593 yield decreased with increasing pH (3-6), whereas yield increased with increasing pH for LU132. During solid substrate production the reverse was true for LU132 whereby yield decreased with increasing pH. The germination potential of the conidia decreased significantly over time in cold storage and the rate of decline was a factor of the strain, pH during morphogenesis, growth media, and storage temperature. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of typical Tunisian fermented milk, rayeb | Samet ...

African Journals Online (AJOL)

Traditional Tunisian fermented milk, rayeb, was produced according to the traditional method. Physicochemical, microstructural, microbiological characteristics and major aromatic compounds evaluation were studied. The results show a decrease in lactose content and pH value and an increase in lactic acid during ...

Development of a fermented ice-cream as influenced by in situ exopolysaccharide production: Rheological, molecular, microstructural and sensory characterization.

Science.gov (United States)

Dertli, Enes; Toker, Omer S; Durak, M Zeki; Yilmaz, Mustafa T; Tatlısu, Nevruz Berna; Sagdic, Osman; Cankurt, Hasan

2016-01-20

This study aimed to investigate the role of in situ exopolysaccharide (EPS) production by EPS(+)Streptococcus thermophilus strains on physicochemical, rheological, molecular, microstructural and sensory properties of ice cream in order to develop a fermented and consequently functional ice-cream in which no stabilizers would be required in ice-cream production. For this purpose, the effect of EPS producing strains (control, strain 1, strain 2 and mixture) and fermentation conditions (fermentation temperature; 32, 37 and 42 °C and time; 2, 3 and 4h) on pH, S. thermophilus count, EPS amount, consistency coefficient (K), and apparent viscosity (η50) were investigated and optimized using single and multiple response optimization tools of response surface methodology. Optimization analyses indicated that functional ice-cream should be fermented with strain 1 or strain mixture at 40-42 °C for 4h in order to produce the most viscous ice-cream with maximum EPS content. Optimization analysis results also revealed that strain specific conditions appeared to be more effective factor on in situ EPS production amount, K and η50 parameters than did fermentation temperature and time. The rheological analysis of the ice-cream produced by EPS(+) strains revealed its high viscous and pseudoplastic non-Newtonian fluid behavior, which demonstrates potential of S. thermophilus EPS as thickening and gelling agent in dairy industry. FTIR analysis proved that the EPS in ice-cream corresponded to a typical EPS, as revealed by the presence of carboxyl, hydroxyl and amide groups with additional α-glycosidic linkages. SEM studies demonstrated that it had a web-like compact microstructure with pores in ice-cream, revealing its application possibility in dairy products to improve their rheological properties. Copyright © 2015. Published by Elsevier Ltd.

Kombucha fermentation test used for various types of herbal teas

Science.gov (United States)

Novi Primiani, C.; Pujiati; Mumtahanah, Mahda; Ardhi, Waskitho

2018-05-01

Tea is a common drink in the community, the benefits of tea can be improved by processing fermented tea called kombucha. Kombucha is a refreshing drink made from tea water plus sugar, obtained through the fermentation process by acetic acid bacteria and fungi, is consumed for its health benefits. The common Kombucha starter is called SCOOBY (Simbyotic of Bacteri and Yeast). Kombucha research using herbal tea is very rarely done, it is necessary kombucha research using a variety of herbal teas to determine the quality of its inhibitory power against bacteria and its quality compared with kombucha berkomposisi tea Camelia sinensis in general. The purpose of this research was to know kombucha quality with ph parameter, thickness of nata, total acid and its inhibitory power to Escherchia coli and Staphylococcus aureus bacteria. This research used Randomized Block Design (RAK) method using 1 tea type treatment, with 3 replications. The first type of green tea (P1), roselle tea (P2), mangosteen peel tea (P3), soursop leaf tea (P4), moringa leaf tea (P5) and yellow leaf tea (P6), so there are 18 treatment combinations. Based on statistical analysis, there was influence of tea type to kombucha quality. Treatments of P1 and P2 were found to have an optimum and significant effect for kombucha. the results in level of acidity [pH] on green tea (P1) was 3.05, nata thickness of 4.63 and total acid of 0.69. Acidity in roselle tea (P2) was 2.86, nata thickness of 3.83, and total acid of 0.71. While the lowest quality was found in the treatment of mangosteen peel (P3) tea with pH 2.57, nata thickness of 0.35, and total acid of 0.79.

Kombucha fermentation and its antimicrobial activity

NARCIS (Netherlands)

Sreeramulu, G.; Zhu, Y.; Knol, W.

2000-01-01

Kombucha was prepared in a tea broth (0.5% w/v) supplemented with sucrose (10% w/v) by using a commercially available starter culture. The pH decreased steadily from 5 to 2.5 during the fermentation while the weight of the 'tea fungus' and the OD of the tea broth increased through 4 days of the

The optimization of l-lactic acid production from sweet sorghum juice by mixed fermentation of Bacillus coagulans and Lactobacillus rhamnosus under unsterile conditions.

Science.gov (United States)

Wang, Yong; Chen, Changjing; Cai, Di; Wang, Zheng; Qin, Peiyong; Tan, Tianwei

2016-10-01

The cost reduction of raw material and sterilization could increase the economic feasibility of l-lactic acid fermentation, and the development of an cost-effective and efficient process is highly desired. To improve the efficiency of open fermentation by Lactobacillus rhamnosus based on sweet sorghum juice (SSJ) and to overcome sucrose utilization deficiency of Bacillus coagulans, a mixed fermentation was developed. Besides, the optimization of pH, sugar concentration and fermentation medium were also studied. Under the condition of mixed fermentation and controlled pH, a higher yield of 96.3% was achieved, compared to that (68.8%) in sole Lactobacillus rhamnosus fermentation. With an optimized sugar concentration and a stepwise-controlled pH, the l-lactic acid titer, yield and productivity reached 121gL(-1), 94.6% and 2.18gL(-1)h(-1), respectively. Furthermore, corn steep powder (CSP) as a cheap source of nitrogen and salts was proved to be an efficient supplement to SSJ in this process. Copyright © 2016 Elsevier Ltd. All rights reserved.

pH-Dependent accumulation of anticancer compound on mycelia in fermentation of marine fungus.

Science.gov (United States)

Zhou, Weiqiang; Cai, Menghao; Na, Ke; Shen, Chu; Zhang, Xiaoxu; Zhou, Xiangshan; Zhao, Wenjie; Zhang, Yuanxing

2014-07-01

The real-time distribution of anticancer 1403C in fermentation broth of marine fungus Halorosellinia sp. was investigated. It was closely related with pH variations, which was, 1403C in the supernatant decreased while that in the mycelia increased with pH rising. There was only 0.5 % of the total 1403C left in the supernatant when pH reached 7.0. The scanning electron microscope then provided information that compounds precipitated on the mycelia when pH rose. Then, the pH-regulation experiments proved that 1403C mainly secreted extracellular and easily dissolved in acidic condition but precipitated and absorbed on the mycelia with the increase of broth pH. Thereby, a pH-regulation strategy was proposed and applied to accumulate 1403C on the mycelia before draw-off of fermentation broth. It significantly simplified purification process and is critical for 1403C preparation of industrial scale.

A review of dark fermentative hydrogen production from biodegradable municipal waste fractions.

Science.gov (United States)

De Gioannis, G; Muntoni, A; Polettini, A; Pomi, R

2013-06-01

Hydrogen is believed to play a potentially key role in the implementation of sustainable energy production, particularly when it is produced from renewable sources and low energy-demanding processes. In the present paper an attempt was made at critically reviewing more than 80 recent publications, in order to harmonize and compare the available results from different studies on hydrogen production from FW and OFMSW through dark fermentation, and derive reliable information about process yield and stability in view of building related predictive models. The review was focused on the effect of factors, recognized as potentially affecting process evolution (including type of substrate and co-substrate and relative ratio, type of inoculum, food/microorganisms [F/M] ratio, applied pre-treatment, reactor configuration, temperature and pH), on the fermentation yield and kinetics. Statistical analysis of literature data from batch experiments was also conducted, showing that the variables affecting the H2 production yield were ranked in the order: type of co-substrate, type of pre-treatment, operating pH, control of initial pH and fermentation temperature. However, due to the dispersion of data observed in some instances, the ambiguity about the presence of additional hidden variables cannot be resolved. The results from the analysis thus suggest that, for reliable predictive models of fermentative hydrogen production to be derived, a high level of consistency between data is strictly required, claiming for more systematic and comprehensive studies on the subject. Copyright © 2013 Elsevier Ltd. All rights reserved.

Membrane gas sensors for fermentation monitoring

Energy Technology Data Exchange (ETDEWEB)

Mandenius, C F

1987-12-01

Results of a study on membrane gas sensors are presented to show their general applicability to fermentation monitoring of volatiles, such as alcohols, organic acids and aldehydes under various process and reactor conditions. Permeable silicone (Noax AB) and teflon (fluorcarbon AB) are tested as material for a gas sensor. The silicone tubing method is mainly used and ethanolic fermentation is performed in the study. Investigation is made to determine the dependence of the sensitivity of the sensors on the temperature, pH, concentration and other properties of fermentation liquid. The effect of temperature on the ethanol response is investigated in the temperature range of 7-50/sup 0/C to reveal that the response time decreases while the sensor's sensitivity increases with an increasing temperature. Comparison among methanol, ethyl acetate, acetaldehyde and ethanol is made with respect to the effect of their concentration on the sensitivity of a sensor. Results of a three-month measurement with the sensor immersed in fermentation liquid are compared with those of GC analysis to investigate the correlation between the sensor's sensitivity and GC analysis data. (11 figs, 17 refs)

Recovery of carboxylic acids at pH greater than pK_a

Energy Technology Data Exchange (ETDEWEB)

Tung, Lisa A. [Univ. of California, Berkeley, CA (United States)

1993-08-01

Economics of producing carboxylic acids by fermentation is often dominated, not by the fermentation cost, but by the cost of recovering and purifying the acids from dilute aqueous solutions. Experiments were performed to measure uptakes of lactic and succinic acids as functions of pH by basic polymeric sorbents; sorbent regeneration was also tested. Performance at pH > pK_a and regenerability depend on sorbent basicity; apparent pK_a and monomer pK{sub a} can be used to predict sorbent performance. Two basic amine extractants, Alamine 336 and Amberlite LA-2, in were also studied; they are able to sustain capacity to higher pH in diluents that stabilize the acid-amine complex through H bonding. Secondary amines perform better than tert-amines in diluents that solvate the additional proton. Competitive sulfate and phosphate, an interference in fermentation, are taken up by sorbents more strongly than by extractants. The third step in the proposed fermentation process, the cracking of the trimethylammonium (TMA) carboxylate, was also examined. Because lactic acid is more soluble and tends to self-esterify, simple thermal cracking does not remove all TMA; a more promising approach is to esterify the TMA lactate by reaction with an alcohol.

The effect of kefir starter on Thai fermented sausage product

Directory of Open Access Journals (Sweden)

Marisa Jatupornpipat

2007-07-01

Full Text Available The effect of kefir starter from Wilderness Family Naturals Company on the initial formulation of Thai fermented sausage were evaluated. The differences found among batches in the main microbial populations and pH were not significant. Only, the total acid of batch D (added the kefir starter 15 ml was significantly higher (P0.05. It is concluded that the addition of kefir starter (7 ml could be useful to improve the final quality of Thai fermented sausages. The addition of kefir starter that initiates rapid acidification of the raw meat and that leads to a desirable sensory quality of the end-product are used for the production of fermented sausages, and represents a way of improving and optimizing the sausage fermentation process and achieving tastier, safer, and healthier products.

Modeling Lactic Fermentation of Gowé Using Lactobacillus Starter Culture.

Science.gov (United States)

de J C Munanga, Bettencourt; Loiseau, Gérard; Grabulos, Joël; Mestres, Christian

2016-12-01

A global model of the lactic fermentation step of gowé was developed by assembling blocks hosting models for bacterial growth, lactic acid production, and the drop of pH during fermentation. Commercial strains of Lactobacillus brevis and of Lactobacillus plantarum were used; their growth was modeled using Rosso's primary model and the gamma concept as a secondary model. The optimum values of pH and temperature were 8.3 ± 0.3, 44.6 ± 1.2 °C and 8.3 ± 0.3, 3.2 ± 37.1 °C with μ max values of 1.8 ± 0.2 and 1.4 ± 0.1 for L. brevis and L. plantarum respectively. The minimum inhibitory concentration of undissociated lactic acid was 23.7 mM and 35.6 mM for L. brevis and L. plantarum , respectively. The yield of lactic acid was five times higher for L. plantarum than for L. brevis , with a yield of glucose conversion to lactic acid close to 2.0 for the former and 0.8 for the latter. A model was developed to predict the pH drop during gowé fermentation. The global model was partially validated during manufacturing of gowé. The global model could be a tool to aid in the choice of suitable starters and to determine the conditions for the use of the starter.

Spatial patterns of soil pH and the factors that influence them in plantation forests of northern China

Science.gov (United States)

Hong, Songbai; Liu, Yongwen; Piao, Shilong

2017-04-01

Climate and anthropogenic activities such as afforestation and nitrogen deposition all impact soil pH. Understanding the spatial pattern of soil pH and the factors that influence it can provide basic information for generating appropriate strategies for soil resource management and protection, especially in light of increasing anthropogenic influences and climate change. In this study, we investigated the spatial and vertical pattern of soil pH and evaluated the influence of climate and nitrogen deposition using 1647 soil profiles 1 meter in depth from 549 plots in plantation forests of northern China. We found that soil pH decreased from the southwest to the northeast in the study region and had a similar spatial pattern before and after afforestation. Furthermore, our results show that climate and nitrogen deposition fundamentally influence the pattern of soil pH. Specifically, increasing precipitation significantly decreased soil pH (with a mean rate of 0.3 for every 100 mm rainfall, ppH (0.13 for every degree centigrade, ppH (ppH directly and indirectly through climate-plant-soil interactions. As the risks from both climate change and nitrogen deposition increase, there is an urgent need to further understanding of soil pH dynamics and to develop informed policies to protect soil resources.

Chemical properties and colors of fermenting materials in salmon fish sauce production.

Science.gov (United States)

Nakano, Mitsutoshi; Sagane, Yoshimasa; Koizumi, Ryosuke; Nakazawa, Yozo; Yamazaki, Masao; Watanabe, Toshihiro; Takano, Katsumi; Sato, Hiroaki

2018-02-01

This data article reports the chemical properties (moisture, pH, salinity, and soluble solid content) and colors of fermenting materials in salmon fish sauce products. The fish sauce was produced by mixing salt with differing proportions of raw salmon materials and fermenting for three months; the salmon materials comprised flesh, viscera, an inedible portion, and soft roe. Chemical properties and colors of the unrefined fish sauce ( moromi ), and the refined fish sauce, were analyzed at one, two, and three months following the start of fermentation. Data determined for all products are provided in table format.

Recovery of nitrogen and phosphorus from alkaline fermentation liquid of waste activated sludge and application of the fermentation liquid to promote biological municipal wastewater treatment.

Science.gov (United States)

Tong, Juan; Chen, Yinguang

2009-07-01

In previous publications we reported that by controlling the pH at 10.0 the accumulation of short-chain fatty acids (SCFA) during waste activated sludge (WAS) fermentation was remarkably improved [Yuan, H., Chen, Y., Zhang, H., Jiang, S., Zhou, Q., Gu, G., 2006. Improved bioproduction of short-chain fatty acids (SCFAs) from excess sludge under alkaline conditions. Environ. Sci. Technol. 40, 2025-2029], but significant ammonium nitrogen (NH(4)-N) and soluble ortho-phosphorus (SOP) were released [Chen, Y., Jiang, S., Yuan, H., Zhou, Q., Gu, G., 2007. Hydrolysis and acidification of waste activated sludge at different pHs. Water Res. 41, 683-689]. This paper investigated the simultaneous recovery of NH(4)-N and SOP from WAS alkaline fermentation liquid and the application of the fermentation liquid as an additional carbon source for municipal wastewater biological nitrogen and phosphorus removal. The central composite design (CCD) of the response surface methodology (RSM) was employed to optimize and model the simultaneous NH(4)-N and SOP recovery from WAS alkaline fermentation liquid. Under the optimum conditions, the predicted and experimental recovery efficiency was respectively 73.4 and 75.7% with NH(4)-N, and 82.0 and 83.2% with SOP, which suggested that the developed models described the experiments well. After NH(4)-N and SOP recovery, the alkaline fermentation liquid was added to municipal wastewater, and the influence of volume ratio of fermentation liquid to municipal wastewater (FL/MW) on biological nitrogen and phosphorus removal was investigated. The addition of fermentation liquid didn't significantly affect nitrification. Both SOP and total nitrogen (TN) removal were increased with fermentation liquid, but there was no significant increase at FL/MW greater than 1/35. Compared to the blank test, the removal efficiency of SOP and TN at FL/MW=1/35 was improved from 44.0 to 92.9%, and 63.3 to 83.2%, respectively. The enhancement of phosphorus and nitrogen

Effects of fermentation by Saccharomyces cerevisiae and ...

African Journals Online (AJOL)

yassine

2013-02-13

Feb 13, 2013 ... Effect of Saccharomyces cerevisiae fermentation on the ... beetroot, fermentation, Saccharomyces cerevisiae, betalain compounds. ... by Saccharomyces cerevisiae strains (González et al., .... Both red and yellow pigments were influenced during S. .... in beverages such as white wine, grape fruit, and green.

Fermentative hydrogen production from liquid swine manure with glucose supplement using an anaerobic sequencing batch reactor

Science.gov (United States)

Wu, Xiao

2009-12-01

one, which contributed to 56-58% of the total soluble metabolite production, indicative of an acetic acid fermentation system, and acetate-to-butyrate ratio was found to be closely related to hydrogen yield. pH level influenced every aspect of the ASBR performance for hydrogen production. ASBR operation at five pHs ranging from 4.4 to 5.6 (4.4, 4.7, 5.0, 5.3, 5.6) showed distinct dynamic profiles of both biogas production and the changes of H2 and CH4 percentage in the biogas during a running period of 22 days. The H2 content in biogas, H 2 production rate and H2 yield were all pH-dependent, in the range of 5.1-36.9 %, 0.71-8.97 L/d and 0.12-1.50 mol-H2/mol-glucose, respectively, and maximum values for all three responses were simultaneously achieved at pH 5.0. Methanogens appeared to be significantly activated at pH of 5.3 or higher since significant CH4 evolution and concurrent reduction in H2 production was observed at pH 5.3 and 5.6. Acetate, propionate, butyrate, valerate, and ethanol were main aqueous products in all pH tests and their distribution was influenced by pH. Analysis of kinetic models developed from modified Gompertz equations for batch experiments showed that pH had a profound effect on all kinetic parameters for hydrogen production including hydrogen potential, maximum hydrogen production rate and the length of the lag phase, as well as the maximum substrate utilization rate. The low pH of 4.4 gave the highest hydrogen production potential but with the lowest hydrogen production rate. A contrast experiment was conducted with an initial pH of 5.3 but not controlled, came up with a rapid pH decline, leading to a low hexose degradation efficiency of 33.2% and a significantly suppressed H2 production, indicating the importance of pH control and the effect of pH on H2 production and substrate consumption. pH 5.0 was verified as the optimal for the proposed fermentation system by kinetic models. An extremely linear relationship (R2= 0.993) between the

Effects of Different Spices Used in Production of Fermented Sausages on Growth of and Curvacin A Production by Lactobacillus curvatus LTH 1174

Science.gov (United States)

Verluyten, Jurgen; Leroy, Frédéric; de Vuyst, Luc

2004-01-01

Lactobacillus curvatus LTH 1174, a fermented sausage isolate, produces the listericidal bacteriocin curvacin A. The effect of different spices relevant for the production of fermented sausages was investigated in vitro through laboratory fermentations with a meat simulation medium and an imposed pH profile relevant for Belgian-type fermented sausages. The influence on the growth characteristics and especially on the kinetics of curvacin A production with L. curvatus LTH 1174 was evaluated. Pepper, nutmeg, rosemary, mace, and garlic all decreased the maximum specific growth rate, while paprika was the only spice that increased it. The effect on the lag phase was minor except for nutmeg and especially for garlic, which increased it, yet garlic was stimulatory for biomass production. The maximum attainable biomass concentration (Xmax) was severely decreased by the addition of 0.40% (wt/vol) nutmeg, while 0.35% (wt/vol) garlic or 0.80% (wt/vol) white pepper increased Xmax. Nutmeg decreased both growth and bacteriocin production considerably. Garlic was the only spice enhancing specific bacteriocin production, resulting in higher bacteriocin activity in the cell-free culture supernatant. Finally, lactic acid production was stimulated by the addition of pepper, and this was not due to the manganese present because an amount of manganese that was not growth limiting was added to the growth medium. Addition of spices to the sausage mixture is clearly a factor that will influence the effectiveness of bacteriocinogenic starter cultures in fermented-sausage manufacturing. PMID:15294818

Effects of different spices used in production of fermented sausages on growth of and curvacin A production by Lactobacillus curvatus LTH 1174.

Science.gov (United States)

Verluyten, Jurgen; Leroy, Frédéric; De Vuyst, Luc

2004-08-01

Lactobacillus curvatus LTH 1174, a fermented sausage isolate, produces the listericidal bacteriocin curvacin A. The effect of different spices relevant for the production of fermented sausages was investigated in vitro through laboratory fermentations with a meat simulation medium and an imposed pH profile relevant for Belgian-type fermented sausages. The influence on the growth characteristics and especially on the kinetics of curvacin A production with L. curvatus LTH 1174 was evaluated. Pepper, nutmeg, rosemary, mace, and garlic all decreased the maximum specific growth rate, while paprika was the only spice that increased it. The effect on the lag phase was minor except for nutmeg and especially for garlic, which increased it, yet garlic was stimulatory for biomass production. The maximum attainable biomass concentration (X(max)) was severely decreased by the addition of 0.40% (wt/vol) nutmeg, while 0.35% (wt/vol) garlic or 0.80% (wt/vol) white pepper increased X(max). Nutmeg decreased both growth and bacteriocin production considerably. Garlic was the only spice enhancing specific bacteriocin production, resulting in higher bacteriocin activity in the cell-free culture supernatant. Finally, lactic acid production was stimulated by the addition of pepper, and this was not due to the manganese present because an amount of manganese that was not growth limiting was added to the growth medium. Addition of spices to the sausage mixture is clearly a factor that will influence the effectiveness of bacteriocinogenic starter cultures in fermented-sausage manufacturing.

Influence of solid state fermentation by Trichoderma spp. on solubility, phenolic content, antioxidant, and antimicrobial activities of commercial turmeric.

Science.gov (United States)

Mohamed, Saleh A; Saleh, Rashad M; Kabli, Saleh A; Al-Garni, Saleh M

2016-05-01

The influence of solid state fermentation (SSF) by Trichoderma spp. on the solubility, total phenolic content, antioxidant, and antibacterial activities of turmeric was determined and compared with unfermented turmeric. The solubility of turmeric was monitored by increase in its phenolic content. The total phenolic content of turmeric extracted by 80% methanol and water after SSF by six species of Trichoderma spp. increased significantly from 2.5 to 11.3-23.3 and from 0.5 to 13.5-20.4 GAE/g DW, respectively. The antioxidant activities of fermented turmeric were enhanced using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid) (ABTS), and ferric ion-reducing antioxidant power (FRAP) assays. The antibacterial activity of fermented turmeric against human-pathogenic bacteria Escherichia coli, Streptococcus agalactiae, Staphylococcus aureus, Entreococcus faecalis, Methicillin-Resistant S. aureus, Klebsiella pneumonia, and Pseudomonas aeruginosae showed a broad spectrum inhibitory effect. In conclusion, the results indicated the potentials of using fermented turmeric as natural antioxidant and antimicrobial material for food applications.

Influence of pH, sucrose concentration and agitation speed on exopolysaccharide production by Lactobacillus confusus TISTR 1498 using coconut water as a raw material substitute

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Phisit Seesuriyachan

2010-08-01

Full Text Available Coconut water (CW was used as a complex nitrogen source for exopolysaccharide (EPS production by Lactobacillus confusus TISTR 1498 to reduce the cost of fermentation medium. EPS production was carried out in a bioreactor using (0.5× modified MRS-sucrose-CW medium, in which three relatively expensive complex nitrogen sources (peptone, yeast extract and beef extract were halved relative to those present in (1× modified MRS-sucrose medium. Fermentation parameters (pH, sucrose concentration and agitation speed were varied in the process of optimisation. Under an optimised condition (pH 5.5, sucrose concentration of 100 g/L and agitation rate of 50 rpm, the maximum EPS level of 38.2 g/L was produced at 35C after 30 h of cultivation. This EPS concentration (38.2 g/L from the (0.5× medium was higher than those produced in the (1× modified MRS-sucrose and (1× modified MRS-sucrose-CW media (21.3 and 31.5 g/L respectively, both having the original concentration of all three complex nitrogen sources. Thus, in a bioreactor where the pH level was properly controlled, the EPS production was greatly enhanced. Sugar concentration also played an important role in the production of EPS.

Enhanced fed-batch production of pyrroloquinoline quinine in Methylobacillus sp. CCTCC M2016079 with a two-stage pH control strategy.

Science.gov (United States)

Si, Zhenjun; Machaku, David; Wei, Peilian; Huang, Lei; Cai, Jin; Xu, Zhinan

2017-06-01

The effects of pH control strategy and fermentative operation modes on the biosynthesis of pyrroloquinoline quinine (PQQ) were investigated systematically with Methylobacillus sp. CCTCC M2016079 in the present work. Firstly, the shake-flask cultivations and benchtop fermentations at various pH values ranging from 5.3 to 7.8 were studied. Following a kinetic analysis of specific cell growth rate (μ x ) and specific PQQ formation rate (μ p ), the discrepancy in optimal pH values between cell growth and PQQ biosynthesis was observed, which stimulated us to develop a novel two-stage pH control strategy. During this pH-shifted process, the pH in the broth was controlled at 6.8 to promote the cell growth for the first 48 h and then shifted to 5.8 to enhance the PQQ synthesis until the end of fermentation. By applying this pH-shifted control strategy, the maximum PQQ production was improved to 158.61 mg/L in the benchtop fermenter, about 44.9% higher than that under the most suitable constant pH fermentation. Further fed-batch study showed that PQQ production could be improved from 183.38 to 272.21 mg/L by feeding of methanol at the rate of 11.5 mL/h in this two-stage pH process. Meanwhile, the productivity was also increased from 2.02 to 2.84 mg/L/h. In order to support cell growth during the shifted pH stage, the combined feeding of methanol and yeast extract was carried out, which brought about the highest concentration (353.28 mg/L) and productivity (3.27 mg/L/h) of PQQ. This work has revealed the potential of our developed simple and economical strategy for the large-scale production of PQQ.

Evaluation of two-phase thermophilic anaerobic methane fermentation for the treatment of garbage

International Nuclear Information System (INIS)

Park, Y.J.; Hong, F.; Japan Science and Technology Agency, Tokyo; Tsuno, H.; Hidaka, T.; Cheon, J.H.; Japan Science and Technology Agency, Tokyo

2004-01-01

Municipal solid wastes (MSW) in Japan are generally incinerated. However, in recent years, garbage has been recognized as a renewable energy source. This has resulted in an increase in the use of biological processes, such as anaerobic digestion, to treat organic waste such as sewage sludge and garbage. The two phases of anaerobic digestion are the acidogenic phase and the methane producing phase. Both differ significantly in their nutritional and physiological requirements. This study evaluated the effectiveness of treating garbage with the two-phase thermophilic methane fermentation system (TPS). The performance of the acid fermentation phase in TPS was examined with particular reference to operational parameters such as pH, hydraulic retention time and organic loading rate on volatile fatty acid fermentation. It was shown that TPS was more efficient than the single-phase thermophilic methane fermentation system (SPS). Acidification control in the first stage resulted in better stability of methane fermentation in the second stage. VFA formation was optimized at a pH of 6. The recovery ratios of VFAs and methane were achieved in the range of 42 to 44 per cent and 88 to 91 per cent of garbage by high organic loading rate respectively. 12 refs., 6 tabs., 4 figs

Application of the Response Surface Methodology to Optimize the Fermentation Parameters for Enhanced Docosahexaenoic Acid (DHA) Production by Thraustochytrium sp. ATCC 26185.

Science.gov (United States)

Wu, Kang; Ding, Lijian; Zhu, Peng; Li, Shuang; He, Shan

2018-04-22

The aim of this study was to determine the cumulative effect of fermentation parameters and enhance the production of docosahexaenoic acid (DHA) by Thraustochytrium sp. ATCC 26185 using response surface methodology (RSM). Among the eight variables screened for effects of fermentation parameters on DHA production by Plackett-Burman design (PBD), the initial pH, inoculum volume, and fermentation volume were found to be most significant. The Box-Behnken design was applied to derive a statistical model for optimizing these three fermentation parameters for DHA production. The optimal parameters for maximum DHA production were initial pH: 6.89, inoculum volume: 4.16%, and fermentation volume: 140.47 mL, respectively. The maximum yield of DHA production was 1.68 g/L, which was in agreement with predicted values. An increase in DHA production was achieved by optimizing the initial pH, fermentation, and inoculum volume parameters. This optimization strategy led to a significant increase in the amount of DHA produced, from 1.16 g/L to 1.68 g/L. Thraustochytrium sp. ATCC 26185 is a promising resource for microbial DHA production due to the high-level yield of DHA that it produces, and the capacity for large-scale fermentation of this organism.

Chemical stability of insulin. 3. Influence of excipients, formulation, and pH.

Science.gov (United States)

Brange, J; Langkjaer, L

1992-01-01

The influence of auxiliary substances and pH on the chemical transformations of insulin in pharmaceutical formulation, including various hydrolytic and intermolecular cross-linking reactions, was studied. Bacteriostatic agents had a profound stabilizing effect--phenol > m-cresol > methylparaben--on deamidation as well as on insulin intermolecular cross-linking reactions. Of the isotonicity substances, NaCl generally had a stabilizing effect whereas glycerol and glucose led to increased chemical deterioration. Phenol and sodium chloride exerted their stabilizing effect through independent mechanisms. Zinc ions, in concentrations that promote association of insulin into hexamers, increase the stability, whereas higher zinc content had no further influence. Protamine gave rise to additional formation of covalent protamine-insulin products which increased with increasing protamine concentration. The impact of excipients on the chemical processes seems to be dictated mainly via an influence on the three-dimensional insulin structure. The effect of the physical state of the insulin on the chemical stability was also complex, suggesting an intricate dependence of intermolecular proximity of involved functional groups. At pH values below five and above eight, insulin degrades relatively fast. At acid pH, deamidation at residue A21 and covalent insulin dimerization dominates, whereas disulfide reactions leading to covalent polymerization and formation of A- and B-chains prevailed in alkaline medium. Structure-reactivity relationship is proposed to be a main determinant for the chemical transformation of insulin.

Evaluation of the effect of supplementing fermented milk with quinoa flour on probiotic activity.

Science.gov (United States)

Casarotti, Sabrina N; Carneiro, Bruno M; Penna, Ana Lúcia B

2014-10-01

In this work, we investigated the effect of supplementing fermented milk with quinoa flour as an option to increase probiotic activity during fermented milk production and storage. Fermented milk products were produced with increasing concentrations of quinoa flour (0, 1, 2, or 3g/100g) and submitted to the following analyses at 1, 14, and 28 d of refrigerated storage: postacidification, bacterial viability, resistance of probiotics to simulated gastrointestinal (GI) conditions, and adhesion of probiotics to Caco-2 cells in vitro. The kinetics of acidification were measured during the fermentation process. The time to reach maximum acidification rate, time to reach pH 5.0, and time to reach pH 4.6 (end of fermentation) were similar for all treatments. Adding quinoa flour had no effect on fermentation time; however, it did contribute to postacidification of the fermented milk during storage. Quinoa flour did not affect counts of Bifidobacterium animalis ssp. lactis BB-12 or Lactobacillus acidophilus La-5 during storage, it did not protect the probiotic strains during simulated GI transit, and it did not have a positive effect on the adhesion of probiotic bacteria to Caco-2 cells in vitro. Additionally, the adhesion of strains to Caco-2 cells decreased during refrigerated storage of fermented milk. Although the addition of up to 3% quinoa flour had a neutral effect on probiotic activity, its incorporation to fermented milk can be recommended because it is an ingredient with high nutritive value, which may increase the appeal of the product to consumers. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Effect of micro-organism and particle size on fermentation of ...

African Journals Online (AJOL)

Aziwo Niba

2013-06-26

Jun 26, 2013 ... fermentation for pH, sugar and organic acids analysis. .... performance liquid chromatography (HPLC) according to the ... are the sums of maltose, glucose and fructose concentrations. n=number of observations per mean.

New instrument for on-line viscosity measurement of fermentation media.

Science.gov (United States)

Picque, D; Corrieu, G

1988-01-01

In an attempt to resolve the difficult problem of on-line determination of the viscosity of non-Newtonian fermentation media, the authors have used a vibrating rod sensor mounted on a bioreactor. The sensor signal decreases nonlinearly with increased apparent viscosity. Electronic filtering of the signal damps the interfering effect of aeration and mechanical agitation. Sensor drift is very low (0.03% of measured value per hour). On the rheological level the sensor is primarily an empirical tool that must be specifically calibrated for each fermentation process. Once this is accomplished, it becomes possible to establish linear or second-degree correlations between the electrical signal from the sensor and the essential parameters of the fermentation process in question (pH of a fermented milk during acidification, concentration of extra cellular polysaccharide). In addition, by applying the power law to describe the rheological behavior of fermentation media, we observe a second-order polynomial correlation between the sensor signal and the behavior index (n).

Characteristics of Milk Fermented by Streptococcus thermophilus MGA45-4 and the Profiles of Associated Volatile Compounds during Fermentation and Storage.

Science.gov (United States)

Dan, Tong; Jin, Rulin; Ren, Weiyi; Li, Ting; Chen, Haiyan; Sun, Tiansong

2018-04-11

The lactic acid bacterium Streptococcus thermophilus is a major starter culture for the production of dairy products. In this study, the physiochemical characteristics of milk fermented by the MGA45-4 isolate of S. thermophilus were analyzed. Our data indicate that milk fermented using S. thermophilus MGA45-4 maintained a high viable cell count (8.86 log10 colony-forming units/mL), and a relatively high pH (4.4), viscosity (834.33 mPa·s), and water holding capacity (40.85%) during 14 days of storage. By analyzing the volatile compound profile using solid-phase microextraction and gas chromatography/mass spectrometry, we identified 73 volatile compounds in the fermented milk product, including five carboxylic acids, 21 aldehydes, 13 ketones, 16 alcohols, five esters, and 13 aromatic carbohydrates. According to the odor activity values, 11 of these volatile compounds were found to play a key role in producing the characteristic flavor of fermented milk, particularly octanal, nonanal, hexanal, 2,3-butanedione, and 1-octen-3-ol, which had the highest odor activity values among all compounds analyzed. These findings thus provide more insights in the chemical/molecular characteristics of milk fermented using S. thermophilus , which may provide a basis for improving dairy product flavor/odor during the process of fermentation and storage.

Physicochemical Properties and Sensory Evaluation of Reduced Fat Fermented Functional Beef Sausage

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Faleeha Hasan Hussein

2017-04-01

Full Text Available Background and Objective: Semi-dry fermented sausages were manufactured from beef meat in three types: without starter culture (control, inoculated with Lactobacillus casei and inoculated with Lactobacillus paracasei. Probiotic fermented sausages are safe and healthy meat products, which receive high commercial interest and growing market shares.Material and Methods: The physico–chemical characteristics (Protein, Moisture, Fat, Ash, Lactic acid value and pH, microbiological features (total aerobic, total mold and yeast andlactic acid bacteria count and sensory evaluation (color, flavor, texture and overall acceptability were analyzed after 0, 10, 20, 30, 40 and 45 days of refrigerated storage at 4°C.Results and Conclusion: There was a significant difference (p≤0.05 in moisture content, which decreased in all samples during the period of refrigerated storage. However, all other parameters such as protein, fat and ash increased. The lactic acid produced during the fermentation by lactic acid bacteria resulted in a decrease in the pH value of all samples, and improved sensory evaluation of the fermented sausage inoculated with Lactobacillus casei and Lactobacillus paracasei during the storage period. The best results were obtained in the fermented sausage inoculated with Lactobacillus paracasei in physico-chemical, microbial and sensory characteristics. Also we could preserve the product at 4°C for 45 days.Conflict of interest: The authors declare that there is no conflict of interest.

Preservative effect of various indigenous plants on fermented milk ...

African Journals Online (AJOL)

SARAH

2014-01-31

Jan 31, 2014 ... Verbenaceae*. Shrub stem. Applied to milk gourd before milk fermentation. Olorien ... powder using an electric grinder (model M10R Japan) and stored until ... measurement cell of a compact pH meter (Horiba B-. 212) and pH ...

Kinetics of β-galactosidase Production by Lactobacillus bulgaricus During pH Controlled Batch Fermentation in Three Commercial Bulk Starter Media

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Saeed Abbasalizadeh

2015-10-01

Full Text Available The potential of bulk starter fermentation strategy for production of a cost-effective and GRAS source of β-galactosidase from a starter culture strain Lactobacillus bulgaricus was investigated. Three different media were selected and the strain, L. bulgaricus DSM 20081 was cultivated in these media under pH-controlled condition (pH = 5.6 at 43°C. The media were: bulk starter medium based on skim milk + whey, bulk starter medium based on whey, and skim milk. Growth and β-lactic acid production parameters were estimated from experimental data with the Garcia and Luedeking-Piret models, respectively. β-galactosidase production kinetics was also simulated using models based on biomass concentration and lactic acid production. Growth in the bulk starter medium based on skim milk + whey resulted in a higher rate of lactic acid production (7.35 ± 0.23  mg lactic acid ml-1 media h-1 and β-galactosidase activity (800.1± 0.7 nmol ONP ml-1 media compared to the other two media (P<0.01. Simulation of β- galactosidase production based on rate of lactic acid production resulted in very good agreement with experimental data for all three tested media. The results revealed the potential of bulk starter fermentation strategy and skim milk + whey based medium for in-house and relatively low cost production of food-grade β-galactosidase by dairy plants.

Effect of Fermentation Parameters on Extra Cellular Tannase Production by Lactobacillus plantarum MTCC 1407

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Kannan Natarajan

2009-01-01

Full Text Available Lactobacillus plantarum MTCC 1407 represents a valuable source of an economically attractive stable long-life tannase with potential for application in various industries. The effect of fermentation parameters such as pH, temperature and agitation speed on the growth of biomass and production of tannase using liquid medium were determined at the end of fermentation period. The optimum values of pH, reaction temperature and agitation speed for tannase activity were 6.0, 30 °C and 125 rpm respectively. The maximum tannase activity was found to be 9.29 U/mL.

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.

On the pH and Osmotic Stress Tolerance of High Ethanol Tolerant ...

African Journals Online (AJOL)

Saccharomyces yeast strains Y13, Y522 and Y1189 isolated from fermenting palm wine juice showed marked differences in their optimum growth pH and possessed osmotolerance comparable to established industrial yeast strains. Shifts in medium pH beyond the growth optimum elicited obvious reductions in growth rate ...

Three Traditional Fermented Baobab Foods from Benin, Mutchayan, Dikouanyouri and Tayohounta: Preparation, Properties and Consumption

NARCIS (Netherlands)

Chadare, F.J.; Gayet, D.P.; Azokpota, P.; Nout, M.J.R.; Linnemann, A.R.; Hounhouigan, M.H.; Boekel, van M.A.J.S.

2010-01-01

Forest food resources contribute significantly to food supply in areas where they grow. Three fermented baobab foods were studied: Dikouanyouri (from seeds, pH = 6.5); Tayohounta (from seed kernels, pH = 7), and Mutchayan (from baobab pulp and sorghum, pH = 4.2). Bacillus spp. (8.5 and 9.5 Log cfu

[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.

Submerged fermentation of Lactobacillus rhamnosus YS9 for γ-aminobutyric acid (GABA production

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Qian Lin

2013-01-01

Full Text Available γ-Aminobutyric acid (GABA is a major inhibitory neurotransmitter in central nervous system, and its application in drugs and functional foods has attracted great attention. To enhance production of y-aminobutyric acid, Lactobacillus rhamnosus YS9, a strain isolated from Chinese traditional fermented food pickled vegetable, was grown under submerged fermentation. Its cultivation conditions were investigated. When culture pH condition was adjusted to the optimal pH of glutamate decarboxylase activity, culture of Lb. rhamnosus YS9 in medium supplemented with 200 mM of monosodium glutamate and 200 µM of pyridoxal phosphate (PLP, produced 187 mM of GABA.

Submerged fermentation of Lactobacillus rhamnosus YS9 for γ-aminobutyric acid (GABA) production

Science.gov (United States)

Lin, Qian

2013-01-01

γ-Aminobutyric acid (GABA) is a major inhibitory neurotransmitter in central nervous system, and its application in drugs and functional foods has attracted great attention. To enhance production of γ-aminobutyric acid, Lactobacillus rhamnosus YS9, a strain isolated from Chinese traditional fermented food pickled vegetable, was grown under submerged fermentation. Its cultivation conditions were investigated. When culture pH condition was adjusted to the optimal pH of glutamate decarboxylase activity, culture of Lb. rhamnosus YS9 in medium supplemented with 200 mM of monosodium glutamate and 200 μM of pyridoxal phosphate (PLP), produced 187 mM of GABA. PMID:24159304

The influence of slaughterhouse waste on fermentative H2 production from food waste: preliminary results.

Science.gov (United States)

Boni, Maria Rosaria; Sbaffoni, Silvia; Tuccinardi, Letizia

2013-06-01

The aim of this study was to evaluate the influence of slaughterhouse waste (SHW; essentially the skin, fats, and meat waste of pork, poultry, and beef) in a fermentative co-digestion process for H2 production from pre-selected organic waste taken from a refectory (food waste [FW]). Batch tests under mesophilic conditions were conducted in stirred reactors filled with different proportions of FW and SHW. The addition of 60% and 70% SHW to a mixture of SHW and FW improved H2 production compared to that in FW only, reaching H2-production yields of 145 and 109 ml g VS 0(-1), respectively, which are 1.5-2 times higher than that obtained with FW alone. Although the SHW ensured a more stable fermentative process due to its high buffering capacity, a depletion of H2 production occurred when SHW fraction was higher than 70%. Above this percentage, the formation of foam and aggregated material created non-homogenous conditions of digestion. Additionally, the increasing amount of SHW in the reactors may lead to an accumulation of long chain fatty acids (LCFAs), which are potentially toxic for anaerobic microorganisms and may inhibit the normal evolution of the fermentative process. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of carbon dioxide on metabolite production and bacterial communities during kimchi fermentation.

Science.gov (United States)

Park, Doo Hyun

2018-04-24

Bacterial communities and metabolites in kimchi fermented under conventional conditions (CC) compared to CO 2 -rich environments (CO 2 ) were analyzed. After a 20-day fermentation, lactic and acetic acid productions were 54 and 69 mM under CC, and 19 and 12 mM under CO 2 , respectively. The final pH of kimchi fermented under CC (CC-fermenting) and CO 2 (CO 2 -fermenting) were 4.1 and 4.7, respectively. For bacterial communities, OTU and Chao1 indices were both 35 in fresh kimchi, 10 and 15 in CC-fermenting kimchi, and 8 and 24 in CO 2 -fermenting kimchi, respectively. Shannon and Simpson indices were 3.47 and 0.93 in fresh kimchi, 1.87-0.06 and 0.46-0.01 in CC-fermenting kimchi, and 1.65-0.44 and 0.63-0.12 in CO 2 -fermenting kimchi, respectively. Non-lactic acid bacteria were eliminated in fermenting kimchi after 12 days under CC and 6 days under CO 2 . I conclude that carbon dioxide can alter bacterial communities, reduce metabolite production, and improve fermented kimchi quality.

Fermentation and storage of probiotic yoghurt from goat’s milk

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Rajka Božanić

2002-04-01

Full Text Available 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 viable cells of Streptococcus thermophilus, Lactobacillus acidophilus and Bifidobacterium ssp. in all fermented samples was comparable 40 : 33 : 27, respectively. During the storage viable count of streptococci and bifidobacteria have not decreased. In supplemented samples viable counts of bifidobacteria were increased and during 28th day of storage were higher for 0.6 logarithms compared to the non supplemented samples. Surviving of lactobacilli was poorer in fermented goat's milk than in fermented cow's milk during storage. The addition of inulin improved the firmness of fermented goat’s and cow’s milks products. Inulin addition partly masked the goat’s flavour of produced yoghurt. During storage the fermented goat's samples were scored better in comparison with cow's samples. Goat’s milk fermented with probiotic bacteria and fortified with inulin complies with the requirements of functional food.

PENGARUH BERBAGAI MERK DRIED YEAST (Saccharomyces sp. DAN pH AWAL FERMENTASI TERHADAP KARAKTERISTIK WINE SALAK

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Ida Bagus Wayan Gunam

2017-09-01

Full Text Available The purpose of this research were to find out the effect of different of dried yeast and initial pH of fermentation on the characteristic of salacca wine, and to determine the appropriate of kind of dried yeast and initial pH of fermentation to produce salacca wine with the best characteristic. This research used Randomized Block Design with factorial pattern. The first factor was the kind of dried yeast brand that consisted of 3 kinds namely Lalvin, Levure and Alcotec. The second factor consisted of 5 levels of initial pH, namely 3.5; 4; 4.5; 5; and 5.5. Each treatment was done 2 times, in order to obtain 30 trial units. The data obtained was analyzed using ANOVA followed by Duncans test. Interactions between treatments had very significant effect on the ethanol content, reduction sugar content, and pH, but had significant effect on acid total content. The best treatment was to use the Alcotec brand dried yeast with a treatment of initial pH as 4, with the following characteristics: ethanol content 12.40%, negative content of methanol, reduction sugar content 5.87%, acid total content 0.20%, pH 3.5 after the fermentation, the color was enough pure yellow, the flavor was strong enough, the taste was strong enough, and rather liked over all acceptance.

Production and partial characterization of serine and metallo peptidases secreted by Aspergillus fumigatus Fresenius in submerged and solid state fermentation.

Science.gov (United States)

da Silva, Ronivaldo Rodrigues; de Freitas Cabral, Tatiana Pereira; Rodrigues, André; Cabral, Hamilton

2013-01-01

Enzyme production varies in different fermentation systems. Enzyme expression in different fermentation systems yields important information for improving our understanding of enzymatic production induction. Comparative studies between solid-state fermentation (SSF) using agro-industrial waste wheat bran and submerged fermentation (SmF) using synthetic media were carried out to determinate the best parameters for peptidase production by the fungus Aspergillus fumigatus Fresen. Variables tested include: the concentration of carbon and protein nitrogen sources, the size of the inoculum, the pH of the media, temperature, and the length of the fermentation process. The best peptidase production during SSF was obtained after 96 hours using wheat bran at 30 °C with an inoculum of 1 × 10(6) spores and yielded 1500 active units (U/mL). The best peptidase production using SmF was obtained after periods of 72 and 96 hours of fermentation in media containing 0.5% and 0.25% of casein, respectively, at a pH of 6.0 and at 30 °C and yielded 40 U/mL. We also found examples of catabolite repression of peptidase production under SmF conditions. Biochemical characterization of the peptidases produced by both fermentative processes showed optimum activity at pH 8.0 and 50 °C, and also showed that their proteolytic activity is modulated by surfactants. The enzymatic inhibition profile using phenylmethylsulfonyl fluoride (PMSF) in SmF and SSF indicated that both fermentative processes produced a serine peptidase. Additionally, the inhibitory effect of the ethylene-diaminetetraacetic acid (EDTA) chelating agent on the peptidase produced by SmF indicated that this fermentative process also produced a metallopeptidase.

Direct Capture of Organic Acids From Fermentation Media Using Ionic Liquids

Energy Technology Data Exchange (ETDEWEB)

Klasson, K.T.

2004-11-03

Several ionic liquids have been investigated for the extraction of organic acids from fermentation broth. Partitioning of representative organic acids (lactic, acetic, and succinic) between aqueous solution and nine hydrophobic ionic liquids was measured. The extraction efficiencies were strongly dependent on pH of the aqueous phase. Distribution coefficient was very good (approximately 60) at low succinic acid concentrations for one of the ionic liquids (trihexyltetradecylphosphonium methanesulfonate) at neutral pH. However, this ionic liquid had to be diluted with nonanol due to its high viscosity in order to be useful. A diluent (trioctylamine) was also added to this mixture. The results suggest that an extraction system based on ionic liquids may be feasible for succinic acid recovery from fermentation broth and that two ideal extraction stages are needed to reduce the concentration from 33 g/L to 1 g/L of succinic acid. Further studies are needed to evaluate other issues related to practical applications, including ionic liquid loss in the process, toxicity effects of ionic liquids during simultaneous fermentation and extractions.

The proton motive force generated in Leuconostoc oenos by L-malate fermentation

NARCIS (Netherlands)

Salema, Madalena; Lolkema, Juke S.; San Romão, M.V.; Loureiro Dias, Maria C.

In cells of Leuconostoc oenos, the fermentation of L-malic acid generates both a transmembrane pH gradient, inside alkaline, and an electrical potential gradient, inside negative. In resting cells, the proton motive force ranged from -170 mV to -88 mV between pH 3.1 and 5.6 in the presence of

Fermentation Process of Cocoa Based on Optimum Condition of Pulp PectinDepolymerization by Endogenous Pectolityc Enzymes

OpenAIRE

Ganda-Putra, G.P; Wrasiati, L.P; Wartini, N.M

2010-01-01

Pulp degradation during cocoa fermentation can be carried out by depolymerization process of pulp pectin using endogenous pectolytic enzymes at optimum condition. The objectives of this research were to study the effect of fermentation process based on optimum condition in terms of temperature and pH of pulp pectin depolymerization using endogenous pectolytic enzymes polygalakturonase (PG) and pectin metyl esterase (PME) and fermentation period in cocoa processing on quality characteristics o...

Influence of Different Fermentation Strategies on the Phenolic Profile of Bilberry Wine (Vaccinium myrtillus L.).

Science.gov (United States)

Behrends, Annika; Weber, Fabian

2017-08-30

Polyphenol rich and especially anthocyanin rich berries like bilberries (Vaccinium myrtillus L.) and derived products such as wine have enjoyed increasing popularity. During winemaking and aging, the phenolic profile undergoes distinct changes, a phenomenon that has been well investigated in grape wine but not in bilberry wine. The present study determined the influence of different fermentation strategies including various pre- and postfermentative heating and cooling concepts on the phenolic profile of bilberry wine. Besides significant differences in total anthocyanin and tannin concentrations, the different fermentation strategies resulted in distinguishable anthocyanin profiles. A very fast aging manifested by a rapid decrease in monomeric anthocyanins of up to 98% during a 12 week storage and a coincident formation of polymeric pigments and pyranoanthocyanins was observed. Several well-known processes associated with production and aging of wine were much more pronounced in bilberry wine compared to grape wine.

Enhanced Microbial, Functional and Sensory Properties of Herbal Yogurt Fermented with Korean Traditional Plant Extracts

Science.gov (United States)

Joung, Jae Yeon; Lee, Ji Young; Ha, Young Sik; Shin, Yong Kook; Kim, Younghoon; Kim, Sae Hun; Oh, Nam Su

2016-01-01

This study evaluated the effects of two Korean traditional plant extracts (Diospyros kaki THUNB. leaf; DK, and Nelumbo nucifera leaf; NN) on the fermentation, functional and sensory properties of herbal yogurts. Compared to control fermentation, all plant extracts increased acidification rate and reduced the time to complete fermentation (pH 4.5). Supplementation of plant extracts and storage time were found to influence the characteristics of the yogurts, contributing to increased viability of starter culture and phenolic compounds. In particular, the increase in the counts of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus was highest (2.95 and 1.14 Log CFU/mL respectively) in DK yogurt. Furthermore, supplementation of the plant extracts significantly influenced to increase the antioxidant activity and water holding capacity and to produce volatile compounds. The higher antioxidant activity and water holding capacity were observed in NN yogurt than DK yogurt. Moreover, all of the sensory characteristics were altered by the addition of plant extracts. Addition of plant extracts increased the scores related to flavor, taste, and texture from plain yogurt without a plant extract, as a result of volatile compounds analysis. Thus, the overall preference was increased by plant extracts. Consequently, supplementation of DK and NN extracts in yogurt enhanced the antioxidant activity and physical property, moreover increased the acceptability of yogurt. These findings demonstrate the possibility of using plant extracts as a functional ingredient in the manufacture of herbal yogurt. PMID:27499669

Enhanced Microbial, Functional and Sensory Properties of Herbal Yogurt Fermented with Korean Traditional Plant Extracts.

Science.gov (United States)

Joung, Jae Yeon; Lee, Ji Young; Ha, Young Sik; Shin, Yong Kook; Kim, Younghoon; Kim, Sae Hun; Oh, Nam Su

2016-01-01

This study evaluated the effects of two Korean traditional plant extracts (Diospyros kaki THUNB. leaf; DK, and Nelumbo nucifera leaf; NN) on the fermentation, functional and sensory properties of herbal yogurts. Compared to control fermentation, all plant extracts increased acidification rate and reduced the time to complete fermentation (pH 4.5). Supplementation of plant extracts and storage time were found to influence the characteristics of the yogurts, contributing to increased viability of starter culture and phenolic compounds. In particular, the increase in the counts of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus was highest (2.95 and 1.14 Log CFU/mL respectively) in DK yogurt. Furthermore, supplementation of the plant extracts significantly influenced to increase the antioxidant activity and water holding capacity and to produce volatile compounds. The higher antioxidant activity and water holding capacity were observed in NN yogurt than DK yogurt. Moreover, all of the sensory characteristics were altered by the addition of plant extracts. Addition of plant extracts increased the scores related to flavor, taste, and texture from plain yogurt without a plant extract, as a result of volatile compounds analysis. Thus, the overall preference was increased by plant extracts. Consequently, supplementation of DK and NN extracts in yogurt enhanced the antioxidant activity and physical property, moreover increased the acceptability of yogurt. These findings demonstrate the possibility of using plant extracts as a functional ingredient in the manufacture of herbal yogurt.

Aerobic Stability and Effects of Yeasts during Deterioration of Non-fermented and Fermented Total Mixed Ration with Different Moisture Levels

OpenAIRE

W. Hao; H. L. Wang; T. T. Ning; F. Y. Yang; C. C. Xu

2015-01-01

The present experiment evaluated the influence of moisture level and anaerobic fermentation on aerobic stability of total mixed ration (TMR). The dynamic changes in chemical composition and microbial population that occur after air exposure were examined, and the species of yeast associated with the deterioration process were also identified in both non-fermented and fermented TMR to deepen the understanding of aerobic deterioration. The moisture levels of TMR in this experiment were adjusted...

Diversity of yeasts involved in the fermentation of tchoukoutou, an opaque sorghum beer from Benin

OpenAIRE

Kayode, A.P.P.; Vieira-Dalode, G.; Linnemann, A.R.; Kotchoni, S.O.; Hounhouigan, A.J.D.; Boekel, van, M.A.J.S.; Nout, M.J.R.

2011-01-01

Opaque sorghum beers are traditional alcoholic beverages in several African countries. Known as tchoukoutou in Benin, the beer is often obtained from an uncontrolled fermentation. It is consumed in an actively fermenting state and has a sour taste. The present study characterized and identified the yeasts involved in the fermentation process of this type of beer using the phenotypical approach. Of 12 beers from 4 different locations, the mean values of the pH, titratable acidity, dry matter c...

Combined effects of nutrients and temperature on the production of fermentative aromas by Saccharomyces cerevisiae during wine fermentation.

Science.gov (United States)

Rollero, Stéphanie; Bloem, Audrey; Camarasa, Carole; Sanchez, Isabelle; Ortiz-Julien, Anne; Sablayrolles, Jean-Marie; Dequin, Sylvie; Mouret, Jean-Roch

2015-03-01

Volatile compounds produced by yeast during fermentation greatly influence the organoleptic qualities of wine. We developed a model to predict the combined effects of initial nitrogen and phytosterol content and fermentation temperature on the production of volatile compounds. We used a Box-Behnken design and response surface modeling to study the response of Lalvin EC1118® to these environmental conditions. Initial nitrogen content had the greatest influence on most compounds; however, there were differences in the value of fermentation parameters required for the maximal production of the various compounds. Fermentation parameters affected differently the production of isobutanol and isoamyl alcohol, although their synthesis involve the same enzymes and intermediate. We found differences in regulation of the synthesis of acetates of higher alcohols and ethyl esters, suggesting that fatty acid availability is the main factor influencing the synthesis of ethyl esters whereas the production of acetates depends on the activity of alcohol acetyltransferases. We also evaluated the effect of temperature on the total production of three esters by determining gas-liquid balances. Evaporation largely accounted for the effect of temperature on the accumulation of esters in liquid. Nonetheless, the metabolism of isoamyl acetate and ethyl octanoate was significantly affected by this parameter. We extended this study to other strains. Environmental parameters had a similar effect on aroma production in most strains. Nevertheless, the regulation of the synthesis of fermentative aromas was atypical in two strains: Lalvin K1M® and Affinity™ ECA5, which produces a high amount of aromatic compounds and was obtained by experimental evolution.

Effects of Freeze-dried Mulberry on Antioxidant Activities and Fermented Characteristics of Yogurt during Refrigerated Storage

OpenAIRE

Sung, Jung-Min; Kim, Young-Boong; Kum, Jun-Seok; Choi, Yun-Sang; Seo, Dong-Ho; Choi, Hyun-Wook; Park, Jong-Dae

2015-01-01

This study investigated the effect of added freeze-dried mulberry fruit juice (FDMJ) (1, 3 and 5%) on the antioxidant activity and fermented characteristic of yogurt during refrigerated storage. A decrease in pH of yogurt and increase in acidity was observed during fermentation. The yogurts with FDMJ exhibited faster rate of pH reduction than control. Initial lactic acid bacteria count of yogurt was 6.49-6.94 Log CFU/g and increased above 9 Log CFU/g in control and 1% in FDMJ yogurt for 24 h....

Modeling Lactic Fermentation of Gowé Using Lactobacillus Starter Culture

Directory of Open Access Journals (Sweden)

Bettencourt de J. C. Munanga

2016-12-01

Full Text Available A global model of the lactic fermentation step of gowé was developed by assembling blocks hosting models for bacterial growth, lactic acid production, and the drop of pH during fermentation. Commercial strains of Lactobacillus brevis and of Lactobacillus plantarum were used; their growth was modeled using Rosso’s primary model and the gamma concept as a secondary model. The optimum values of pH and temperature were 8.3 ± 0.3, 44.6 ± 1.2 °C and 8.3 ± 0.3, 3.2 ± 37.1 °C with μmax values of 1.8 ± 0.2 and 1.4 ± 0.1 for L. brevis and L. plantarum respectively. The minimum inhibitory concentration of undissociated lactic acid was 23.7 mM and 35.6 mM for L. brevis and L. plantarum, respectively. The yield of lactic acid was five times higher for L. plantarum than for L. brevis, with a yield of glucose conversion to lactic acid close to 2.0 for the former and 0.8 for the latter. A model was developed to predict the pH drop during gowé fermentation. The global model was partially validated during manufacturing of gowé. The global model could be a tool to aid in the choice of suitable starters and to determine the conditions for the use of the starter.

Fermentative hydrogen production by two novel strains of Enterobacter aerogenes HGN-2 and HT 34 isolated from sea buried crude oil pipelines

Energy Technology Data Exchange (ETDEWEB)

Jayasinghearachchi, H.S.; Sarma, Priyangshu M.; Singh, Sneha; Mandal, Ajay K.; Lal, Banwari [Environmental and Industrial Biotechnology Division, The Energy and Resource Institute, Darbari Seth Block, Habitat Place, Lodhi Road, New Delhi 110 003 (India); Aginihotri, Anil [Corporate HSF, Oil and Natural Gas Corporation, New Delhi (India)

2009-09-15

Present study investigated fermentative hydrogen production of two novel isolates of Enterobacter aerogenes HGN-2 and HT 34 isolated from oil water mixtures. The two isolates were identified as novel strains of E. aerogenes based on 16S rRNA gene. The batch fermentations of two strains from glucose and xylose were carried out using economical culture medium under various conditions such as temperature, initial pH, NaCl, Ni{sup +}/Fe{sup ++}, substrate concentrations for enhanced fermentation process. Both the strains favoured wide range of pH (6.5-8.0) at 37 C for optimum production (2.20-2.23 mol H{sub 2}/mol-glucose), which occurred through acetate/butyrate pathway. At 55 C, both strains favoured 6.0-6.5 and acetate type fermentation was predominant in HT 34. Hydrogen production by HT 34 from xylose was highly pH dependant and optimum production was at pH 6.5 (circa 1.98 mol-H{sub 2}/mol-xylose) through acetate pathway. The efficiency of the strain HGN-2 at pH 6.5 was 1.92-1.94 mol-H{sub 2}/mol-xylose, and displayed both acetate and butyrate pathways. At 55 C, very low hydrogen production was detected (less than 0.5 m mol/mol-xylose). (author)

Effects of seed fermentation method on seed germination and vigor ...

African Journals Online (AJOL)

The present study was conducted to examine the influence of Lagenaria siceraria seed fermentation method on seed germination and vigor. Three seed fermentation methods (fermented in ambient air, plastic bag stored in ambient or in plastic bag buried) were tested on two cultivars during two years. Seed germination and ...

Fermentative hydrogen production by the newly isolated Enterobacter asburiae SNU-1

Energy Technology Data Exchange (ETDEWEB)

Shin, Jong-Hwan; Hyun Yoon, Jong; Eun Kyoung Ahn; Park, Tai Hyun [School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744 (Korea); Kim, Mi-Sun [Biomass Research Team, Korea Institute of Energy Research, Daejeon 305-343 (Korea); Jun Sim, Sang [Department of Chemical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea)

2007-02-15

A new fermentative hydrogen-producing bacterium was isolated from a domestic landfill and identified as Enterobacter asburiae using 16S rRNA gene sequencing and DNA-DNA hybridization methods. The isolated bacterium, designated as Enterobacter asburiae SNU-1, is a new species that has never been examined as a potential hydrogen-producing bacterium. This study examined the hydrogen-producing ability of Enterobacter asburiae SNU-1. During fermentation, the hydrogen was mainly produced in the stationary phase. The hydrogen yield based on the formate consumption was 0.43 mol hydrogen/mol formate. This strain was able to produce hydrogen over a wide range of pH (4-7.5), with the optimum pH being pH 7. The level of hydrogen production was also affected by the initial glucose concentration, and the optimum value was found to be 25 g glucose/l. The maximum and overall hydrogen productivities were 398 and 174 ml/l/hr, respectively, at pH 7 with an initial glucose concentration of 25 g/l. This strain could produce hydrogen from glucose and many other carbon sources such as fructose, sucrose, and sorbitol. (author)

Individual whey protein components influence lipid oxidation dependent on pH

DEFF Research Database (Denmark)

Horn, Anna Frisenfeldt; Nielsen, Nina Skall; Jacobsen, Charlotte

In emulsions, lipid oxidation is expected to be initiated at the oil-water interface. The properties of the emulsifier used and the composition at the interface is therefore expected to be of great importance for the resulting oxidation. Previous studies have shown that individual whey protein...... by affecting the preferential adsorption of whey protein components at the interface. The aim of the study was to compare lipid oxidation in 10% fish oil-in-water emulsions prepared with 1% whey protein having either a high concentration of α-lactalbumin, a high concentration of β-lactoglobulin or equal...... amounts of the two. Emulsions were prepared at pH4 and pH7. Emulsions were characterized by their droplet sizes, viscosities, and contents of proteins in the water phase. Lipid oxidation was assessed by PV and secondary volatile oxidation products. Results showed that pH greatly influenced the oxidative...

Microbiota and metabolome during controlled and spontaneous fermentation of Nocellara Etnea table olives.

Science.gov (United States)

Randazzo, Cinzia Lucia; Todaro, Aldo; Pino, Alessandra; Pitino, Iole; Corona, Onofrio; Caggia, Cinzia

2017-08-01

This study is aimed to investigate bacterial community and its dynamics during the fermentation of Nocellara Etnea table olives and to study its effect on metabolome formation. Six different combination of bacterial cultures (BC1-BC6) were used as starters for table olive fermentation and one additional process, conducted without addition of any starters, was used as control (C). The processes were conducted in triplicate and, overall, 21 vessels were performed at industrial scale. The fermentation was monitored for 120 days through culture-dependent and -independent approaches. Microbial counts of the main microbial groups revealed slight differences among brine samples, with the exception of LAB counts and Enterobacteriaceae, which were higher and lower, respectively, in most of the inoculated samples than the control ones. In addition, results demonstrated that the use of bacterial cultures (except the BC1), singly or in different combinations, clearly influenced the fermentation process reducing the final pH value below 4.50. When microbiota was investigated through sequencing analysis, data revealed the presence of halophilic bacteria and, among lactobacilli, the dominance of Lactobacillus plantarum group at the initial stage of fermentation, in all brine samples, except in the BC5 in which dominated Lactobacillus casei group. At 60 and 120 days of fermentation, an overturned bacterial ecology and an increase of biodiversity was observed in all samples, with the occurrence of Lactobacillus paracollinoides, Lactobacillus acidipiscis and Pediococcus parvulus. Correlation between bacterial OTU and volatile organic compounds (VOCs) revealed that, aldehydes and alcohol compounds exhibited a positive correlation with Proteobacteria, while several esters with LAB and Hafnia. In particular, esters, associated with fruity and floral notes, were positively correlated to L. paracollinoides, L. acidipiscis, and P. parvulus species. Although the VOCs amounts were sample

Exploring process dynamics by near infrared spectroscopy in lactic fermentations

DEFF Research Database (Denmark)

Svendsen, Carina; Cieplak, Tomasz; van der Berg, Franciscus Winfried J

2016-01-01

In the industrial production of yoghurt, measurement of pH is normally the only in-line technique applied as a real-time monitoring signalfor following the dynamics during the fermentation process. However, every dairy company would benefit from an in-line technique giving information about...... the chemical composition, physical/textural properties and/or microbial contamination. In this study lactic fermentation batches with the starter bacteria Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus are explored by in-line near infrared (NIR) spectroscopy. The dynamics obtained...

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.

Physical and textural characteristics of fermented milk products obtained by kombucha inoculums with herbal teas

Directory of Open Access Journals (Sweden)

Malbaša Radomir V.

2012-01-01

Full Text Available In this investigation, kombucha fermented milk products were produced from milk with 1.6% milk fat using 10% (v/v kombucha inoculums cultivated on the extracts of peppermint and stinging nettle. The fermentation process was conducted at temperatures of 37, 40 and 43°C. Fermentation was stopped when the pH value of 4.5 was reached. The fermentation process was shortened with an increase of temperature. Physical characteristics of the fermented products were determined by using standard methods of analysis. Textural characteristics were determined by texture profile analysis. The obtained products showed good physical and textural characteristics, typical for the yoghurt-like products. [Projekat Ministarstva nauke Republike Srbije, br. III-46009

Shear bond strength of one-step self-etch adhesives: pH influence

Science.gov (United States)

Poggio, Claudio; Beltrami, Riccardo; Scribante, Andrea; Colombo, Marco; Chiesa, Marco

2015-01-01

Background: The aim of this study was to compare the shear bond strength of four one-step self-etch adhesives with different pH values to enamel and dentin. Materials and Methods: In this in vitro study, 200 bovine permanent mandibular incisors were used. Four one-step self-etch adhesives with different pH values were tested both on enamel and on dentin: Adper™ Easy Bond Self-Etch Adhesive (pH = 0.8-1), Futurabond NR (pH=2), G-aenial Bond (pH = 1.5), Clearfil S3 Bond (pH = 2.7). After adhesive systems application, a nanohybrid composite resin was inserted into the bonded surface. The specimens were placed in a universal testing machine. The shear bond strength was performed at a cross-head speed of 1 mm/min until the sample rupture. The shear bond strength values (MPa) of the different groups were compared with analysis of variance after that Kolmogorov and Smirnov tests were applied to assess normality of distributions. P enamel shear bond strength, the highest shear bond strength values were reported with Futurabond NR (P adhesive systems showed lower shear bond strength values with significant differences between them (P 0.05). Conclusion: The pH values of adhesive systems did not influence significantly their shear bond strength to enamel or dentin. PMID:26005459

Toxin production in food as influenced by pH, thermal treatment and ...

African Journals Online (AJOL)

Toxin production in food as influenced by pH, thermal treatment and chemical ... carrot, spinach, pepper, tomato, onion and cooked food samples (rice, yam, beans, ... on the growth rate and toxin elaboration of E. coli, K. aerogenes, C. freundii, ...

Characteristics of Milk Fermented by Streptococcus thermophilus MGA45-4 and the Profiles of Associated Volatile Compounds during Fermentation and Storage

Directory of Open Access Journals (Sweden)

Tong Dan

2018-04-01

Full Text Available The lactic acid bacterium Streptococcus thermophilus is a major starter culture for the production of dairy products. In this study, the physiochemical characteristics of milk fermented by the MGA45-4 isolate of S. thermophilus were analyzed. Our data indicate that milk fermented using S. thermophilus MGA45-4 maintained a high viable cell count (8.86 log10 colony-forming units/mL, and a relatively high pH (4.4, viscosity (834.33 mPa·s, and water holding capacity (40.85% during 14 days of storage. By analyzing the volatile compound profile using solid-phase microextraction and gas chromatography/mass spectrometry, we identified 73 volatile compounds in the fermented milk product, including five carboxylic acids, 21 aldehydes, 13 ketones, 16 alcohols, five esters, and 13 aromatic carbohydrates. According to the odor activity values, 11 of these volatile compounds were found to play a key role in producing the characteristic flavor of fermented milk, particularly octanal, nonanal, hexanal, 2,3-butanedione, and 1-octen-3-ol, which had the highest odor activity values among all compounds analyzed. These findings thus provide more insights in the chemical/molecular characteristics of milk fermented using S. thermophilus, which may provide a basis for improving dairy product flavor/odor during the process of fermentation and storage.

Optimization of fermentation conditions for ethanol production from whey

Energy Technology Data Exchange (ETDEWEB)

Castillo, F J; Izaguirre, M F; Michelena, V; Moreno, B

1982-01-01

Optimal conditions for ethanol production in 7% whey solutions by the yeast Candida pseudotropicalis ATCC 8619 included an initial pH of 4.57 and 30 degrees. Complete fermentation of the available lactose took place without supplementary nutrients; additions of N and P salts, yeast extract, or corn steep liquor resulted in increased yeast production and lower ethanol yields. A possible correlation was observed between increases in yeast inocula and lactose utilization and ethanol production rates; 8.35 g ethanol/L was obtained within 22 hours by using a yeast inoculum of 13.9 g/L. No differences in fermentation rates or ethanol yields were observed when whole or deproteinized whey solutions were used. Concentrated whey permeates, obtained after removal of the valuable proteins from whey, can be effectively fermented for ethanol production.

Fermented liquid feed - Feed processing has a big impact on microbial degradation of free lysine during fermentation

DEFF Research Database (Denmark)

Canibe, Nuria; Jensen, Bent Borg

2010-01-01

In order to investigate the influence of feed processing on the microbial degradation of free lysine during fermentation of liquid feed, a study at laboratory scale was carried out. Based on a standard Danish grower diet with extra free amino acids added, two treatments were prepared: treatment 1...... a few hours of fermentation, the levels in both treatments became similar. The concentration of acetic acid was higher in the mixture containing the mash feed than in that containing the pelleted feed. The disappearance of free lysine was much higher when mash feed was fermented than when the same...

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.

The Influence of Brewer’s Yeast Autolysate and Lactic Acid Bacteria on the Production of a Functional Food Additive Based on Beetroot Juice Fermentation

Directory of Open Access Journals (Sweden)

Josip Baras

2004-01-01

Full Text Available The importance of »functional foods« in the world is increasing, and the procedures for their production are under intense development. The goal of this paper is to optimise the production of a functional food additive based on beetroot juice (Beta vulgaris L. using brewer’s yeast autolysate. In order to improve the nutritive properties of the product and to preserve it, the possibility of beetroot juice fermentation using a Lactobacillus species has been investigated. Comparative investigations of three bacteria cultures (L. plantarum A112, L. acidophilus BGSJ15-3 and L. acidophilus NCDO1748 during fermentation in two media, beetroot juice and a mixture of beetroot juice with an autolysate of brewer´s yeast, have been performed. The poorest fermentative activity and growth in both substrates was observed using the L. acidophilus NCDO1748 culture. The two cultures demonstrated better fermentative activity in the mixture of tested substrates, while acidifying activity (production of lactic acid and a decrease in pH of the L. acidophilus BGSJ15-3 culture was considerably better than that of the L. plantarum A112 culture. L. plantarum A112 culture showed better growth than L. acidophilus BGSJ15-3. From the results obtained, it has been concluded that the L. plantarum A112 and L. acidophilus BGSJ15-3 can be successfully used for fermentation of the mixture of beetroot juice and brewer’s yeast autolysate in order to obtain a functional food additive.

Characterization of lactic acid bacteria isolated from a Thai low-salt fermented fish product and the role of garlic as substrate for fermentation

DEFF Research Database (Denmark)

Paludan-Müller, Christine; Huss, Hans Henrik; Gram, Lone

1999-01-01

associated with fish fillet and minced fish, Lactobacillus paracasei subsp. paracasei with boiled rice and Weisella confusa with garlic mix and banana leaves. In addition, Lactobacillus plantarum, Lactobacillus pentosus and Pediococcus pentosaceus were isolated from raw materials. A succession of aciduric......Lactic acid bacteria (LAB) isolated from raw materials (fish, rice, garlic and banana leaves) and processed som-fak (a Thai low-salt fermented fish product) were characterized by API 50- CH and other phenotypic criteria. Lactococcus lactis subsp. lactis and Leuconostoc citreum were specifically....... paracasei, or garlic fermenting Lb. plantarum and Pd. pentosaceus, or a combination of these strains were inoculated into laboratory prepared som-fak with or without garlic. In som-fak without garlic, pH was above 4.8 after three days, irrespective of addition of mixed LAB cultures. The starch fermenting...

Influence of pH on the growth, laccase activity and RBBR decolorization by tropical basidiomycetes

Directory of Open Access Journals (Sweden)

Sérgio Luiz Moreira Neto

2009-10-01

Full Text Available The basidiomycete fungi Lentinus crinitus and Psilocybe castanella are being evaluated in a bioremediation process of soils contaminated with organochlorine industrial residues in the Baixada Santista, São Paulo. The aim of the present study was to determine the influence of pH on the fungal growth, in vitro decolorization of anthraquinonic dye Remazol Brilliant Blue R (RBBR and laccase activity. The pH of the culture medium influenced the growth of L. crinitus and P. castanella, which presented less growth at pH 5.9 and pH 2.7, respectively. The fungi were able to modify the pH of the culture medium, adjusting it to the optimum pH for growth which was close to 4.5. Decolorization of the RBBR was maximal at a pH of 2.5 to 3.5. Higher laccase activity was observed at pH 3.5 and pH 4.5 for L. crinitus and P. castanella, respectively. pH was found to be an important parameter for both the growth of these fungi and the enzymatic system involved in RBBR decolorization.Os fungos basidiomicetos Lentinus crinitus e Psilocybe castanella estão sendo avaliados em processo de biorremediação de solos contaminados com resíduos industriais organoclorados, na Baixada Santista, SP. O presente estudo avaliou a influência do pH no crescimento, na descoloração in vitro do corante Azul Brilhante de Remazol R (RBBR e na atividade de lacase durante cultivo destes fungos, de forma a subsidiar a otimização do processo. O pH do meio influenciou o crescimento de L. crinitus e de P. castanella, com menor biomassa em pH 5,9 e pH 2,7, respectivamente. Os fungos foram capazes de modificar o pH inicial do meio de cultura, de modo a ajustá-lo ao valor ótimo de crescimento, próximo a 4,5. Descoloração in vitro do RBBR foi máxima em pH 2,5 e 3,5. Maiores atividades de lacase foram obtidas em pH 3,5 e em pH 4,5 para L. crinitus e P. castanella, respectivamente. Evidenciou-se que o pH é um parâmetro importante para o crescimento destes fungos, atividade de lacase

Effects of Lactic Acid Fermentation on the Retention of Β-Carotene Content in Orange Fleshed Sweet Potatoes

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Benard O. Oloo

2014-04-01

Full Text Available This study aimed to establish the effects of lactic fermentation on the levels of β-carotene in selected  orange fleshed sweet potato (OFSP varieties from Kenya.  Furthermore,it sought to demonstrate fermentation as a potential process for making new products from sweet potato with enhanced nutraceutical attributes. The varieties (Zapallo, Nyathiodiewo and SPK004/06 were fermented with Lactobacillus plantarum MTCC 1407 at 25 ± 2°C for 48 h and kept for 28 days to make lacto-pickles. During fermentation both analytical [pH, titratable acidity (TA, lactic acid (LA, starch, total sugar, reducing sugar (g/kg roots, texture (N/m2, β-carotene (mg/kg roots] and sensory (texture, taste, flavour and after taste attributes of sweet potato lacto-juice were evaluated. Process conditions were optimized by varying brine levels, with fermentation time. A UV-visible spectrophotometer was used to identify and quantify β-carotene. Any significant variations (p < 0.05 in analytical attributes between the fermented and unfermented samples (pH, LA, TA and β-carotene concentration of lacto-pickles, prepared from the potato roots, were assessed. The study reported a final composition of 156.49mg/kg, 0.53mg/kg, 0.3N/m2, 1.3g/kg, 5.86g/kg, 0.5g/kg and 5.86g/kg for β-carotene, Ascorbic acid, texture; Starch, total sugars, LA and TA respectively, and a pH of 3.27. The fermented products were subjected to flavour profiling by a panel. The product sensory scores were 1.5 to 2.5 on a 5 point hedonic scale, ranging from dislike slightly to like much. The products with brine levels at 4 and 6% were most preferred. The retention of β-carotene was 93.97%. This demonstrated lactic acid fermentation as a better method for processing OFSP as the main nutritional attributes are retained. The final product was resistant to spoilage microorganisms after 28 days of fermentation. Further preservation could be obtained by addition of sodium metabisulphite. In conclusion, Lactic

Antioxidant and Angiotensin-Converting Enzyme Inhibitory Activity of Eucalyptus camaldulensis and Litsea glaucescens Infusions Fermented with Kombucha Consortium

OpenAIRE

Gamboa-Gómez, Claudia I.; González-Laredo, Rubén F.; Gallegos-Infante, José Alberto; Pérez, MŞ del Mar Larrosa; Moreno-Jiménez, Martha R.; Flores-Rueda, Ana G.; Rocha-Guzmán, Nuria E.

2016-01-01

Physicochemical properties, consumer acceptance, antioxidant and angiotensin-converting enzyme (ACE) inhibitory activities of infusions and fermented beverages of Eucalyptus camaldulensis and Litsea glaucescens were compared. Among physicochemical parameters, only the pH of fermented beverages decreased compared with the unfermented infusions. No relevant changes were reported in consumer preference between infusions and fermented beverages. Phenolic profi le measured by UPLC MS/MS analysis d...

Acidogenic fermentation of the organic fraction of municipal solid waste and cheese whey for bio-plastic precursors recovery - Effects of process conditions during batch tests.

Science.gov (United States)

Girotto, Francesca; Lavagnolo, Maria Cristina; Pivato, Alberto; Cossu, Raffaello

2017-12-01

The problem of fossil fuels dependency is being addressed through sustainable bio-fuels and bio-products production worldwide. At the base of this bio-based economy there is the efficient use of biomass as non-virgin feedstock. Through acidogenic fermentation, organic waste can be valorised in order to obtain several precursors to be used for bio-plastic production. Some investigations have been done but there is still a lack of knowledge that must be filled before moving to effective full scale plants. Acidogenic fermentation batch tests were performed using food waste (FW) and cheese whey (CW) as substrates. Effects of nine different combinations of substrate to inoculum (S/I) ratio (2, 4, and 6) and initial pH (5, 7, and 9) were investigated for metabolites (acetate, butyrate, propionate, valerate, lactate, and ethanol) productions. Results showed that the most abundant metabolites deriving from FW fermentation were butyrate and acetate, mainly influenced by the S/I ratio (acetate and butyrate maximum productions of 21.4 and 34.5g/L, respectively, at S/I=6). Instead, when dealing with CW, lactate was the dominant metabolite significantly correlated with pH (lactate maximum production of 15.7g/L at pH = 9). Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Anionic Salt and Highly Fermentable Carbohydrate Supplementations on Urine pH and on Experimentally Induced Hypocalcaemia in Cows

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Enemark JMD

2004-09-01

Full Text Available The objective of this experiment was to determine the effect of dietary grain on calcium homeostasis. Six rumen-fistulated dairy cows with 3 or more previous lactations and no history of parturient paresis were randomly assigned to a sequence of diets in a crossover study with 4 periods of 10 days each. Dietary treatments were: A control ration consisting of wrap grass silage alone (1, the control ration supplemented with ammonium chloride and ammonium sulphate salt solution (2, control ration following a period with supplementation (3 and control ration supplemented with increasing amounts of barley from 4 to 10 kg/cow per day, expected to produce subclinical rumen acidosis (4. Daily intake of the diets was adjusted to 14 kg DM/cow per day. On day 11, the calcium-regulating mechanisms in cows were challenged until recumbency by a standardized intravenous EDTA infusion and cows were left to recover spontaneously. Anion supplementation and the feeding of highly fermentable carbohydrate lowered urine pH below 7.0 due to subclinical acidosis. During spontaneous recovery from EDTA induced hypocalcaemia, the cows more quickly regained a whole blood free calcium concentration of 1.00 mmol/L if they had most recently been supplemented with either anionic salts or with increasing amounts of barley, as compared to the basic ration. It is concluded that so-called slug-feeding or 'steaming up' with highly fermentable carbohydrates before parturition in milk fever susceptible cows enhanced calcium homeostasis similar to the effect seen in cows on anionic diets.

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

Science.gov (United States)

Kundiyana, Dimple Kumar Aiyanna

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

Batch fermentation of black tea by kombucha: A contribution to scale-up

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Malbaša Radomir V.

2005-01-01

Full Text Available Local domestic Kombucha was used in fermentation of 1.5 g L-1 of black tea (Indian tea, " Vitamin ", Horgoš, Serbia and Montenegro, sweetened with approximately 70 g L'1 of sucrose. Inoculation was performed either with 10% or 15% (v/v of fermentation broth from previous process. The fermentation was conducted in geometrically similar vessels with 0.4 L, 0.8 L, 4 L and 8 L of substrate, at 22±1 °C for 28 days. The samples were analyzed after 3, 4 5, 6, 7, 10, 14 and 28 days, so that their pH values, content of total acids sucrose, glucose and fructose contents, as well as contents of ethanol and vitamin C were determined. Based on the experiment design, the response surface for the product pH, as a function of time, beverage volume and inoculum concentration, was defined in the form of a second-order polynomial. From the obtained response surface, a formula for scaling-up of the process was derived.

Fermentative utilization of glycerol residue for the production of acetic acid

Science.gov (United States)

Irvan; Trisakti, B.; Hasibuan, R.; Joli, M.

2018-02-01

Glycerol residue, frequently known as pitch, is a waste produced from the downstream product of crude glycerine distillation. With the increasing need of pure glycerine in the world, the glycerol residue produced is also increasing. Glycerol residue is a solid waste at room temperature, highly alkaline (pH > 13), corrosive, and categorized as hazardous and poisonous waste. In this research, acetic acid was produced from glycerol residue through the anaerobic fermentation process by using purple non-sulphur photosynthetic bacteria. The purpose of this study was to find out the influence of concentration change of glycerol residue on time and to find out the possibility of glycerol residue to be utilized as acetic acid. In this research, at first 400 g of glycerol residue was diluted with 200 ml of distilled water to change the glycerine phase, from solid to liquid at room temperature, acidified by using hydrochloric acid until pH 2. The top layer formed was fatty acid and triglycerides that should be removed. Meanwhile, the bottom layer was diluted glycerol residue which was then neutralized with caustic soda. To produce acetic acid, glycerol residue with various concentrations, salt, and purple non-sulphur photosynthetic bacteria were put together into a 100 ml bottle which had been previously sterilized, then incubated for four weeks under the light of 40-watt bulb. The result showed that on the 28th day of fermentation, the produced acetic acid were 0.28, 1.85, and 0.2% (w/w) by using glycerine with the concentration of 0.5, 1.0, and 1.5% (w/w), respectively.

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).

Effect of pH on simultaneous saccharification and isomerization by glucoamylase and glucose isomerase.

Science.gov (United States)

Mishra, Abha; Debnath Das, Meera

2002-01-01

pH and temperature play critical roles in multistep enzymatic conversions. In such conversions, the optimal pH for individual steps differs greatly. In this article, we describe the production of glucoamylase (from Aspergillus oryzae MTCC152 in solid-state fermentation) and glucose isomerase (from Streptomyces griseus NCIM2020 in submerged fermentation), used in industries for producing high-fructose syrup. Optimum pH for glucoamylase was found to be 5.0. For glucose isomerase, the optimum pH ranged between 7.0 and 8.5, depending on the type of buffer used. Optimum temperature for glucoamylase and glucose isomerase was 50 and 60 degrees C, respectively. When both the enzymatic conversions were performed simultaneously at a compromised pH of 6.5, both the enzymes showed lowered activity. We also studied the kinetics at different pHs, which allows the two-step reaction to take place simultaneously. This was done by separating two steps by a thin layer of urease. Ammonia generated by the hydrolysis of urea consumed the hydrogen ions, thereby allowing optimal activity of glucose isomerase at an acidic pH of 5.0.

Amylolysis of raw corn by Aspergillus niger for simultaneous ethanol fermentation

Energy Technology Data Exchange (ETDEWEB)

Han, I.Y.; Steinberg, M.P.

1987-01-01

The novelty of this approach was hydrolysis of the raw starch in ground corn to fermentable sugars that are simultaneously fermented to ethanol by yeast in a nonsterile environment. Thus, the conventional cooking step can be eliminated for energy conservation. A koji of Aspergillus niger grown on whole corn for 3 days was the crude enzyme source. A ratio of 0.2 g dry koji/g total solids was found sufficient. Optimum pH was 4.2. Ethanol concentration was 7.7% (w/w) in the aqueous phase with 92% raw starch conversion. Agitation increased rate. Sacharification was the rate-limiting step. The initial ethanol concentration preventing fermentation was estimated to be 8.3% by weight. (Refs. 96).

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

Microbiota in fermented feed and swine gut.

Science.gov (United States)

Wang, Cheng; Shi, Changyou; Zhang, Yu; Song, Deguang; Lu, Zeqing; Wang, Yizhen

2018-04-01

Development of alternatives to antibiotic growth promoters (AGP) used in swine production requires a better understanding of their impacts on the gut microbiota. Supplementing fermented feed (FF) in swine diets as a novel nutritional strategy to reduce the use of AGP and feed price, can positively affect the porcine gut microbiota, thereby improving pig productivities. Previous studies have noted the potential effects of FF on the shift in benefit of the swine microbiota in different regions of the gastrointestinal tract (GIT). The positive influences of FF on swine gut microbiota may be due to the beneficial effects of both pre- and probiotics. Necessarily, some methods should be adopted to properly ferment and evaluate the feed and avoid undesired problems. In this mini-review, we mainly discuss the microbiota in both fermented feed and swine gut and how FF influences swine gut microbiota.

Effects of irradiation on quality of fermented sausage

International Nuclear Information System (INIS)

Yu Hai; Li Xiang; Li Suzheng; Qin Chunjun; Ge Qingfeng; Jiang Yunsheng; Wang Zhijun; Cao Hong; Chen Xiulan

2010-01-01

The fermented sausages were irradiated by 60 Co γ-rays at 0, 2, 4 and 6 kGy, and the quality of the fermented sausages were studied. The results showed that there were significant differences on the water contents between irradiated sausage and CK (P < 0.05), but no change on NaCl contents. pH values of 0 and 2 kGy groups were significantly higher than that of 4 and 6 kGy groups (P < 0.05). Amino acids contents of 4 kGy irradiated sausage were significantly higher than that of 2 and 6 kGy groups. The highest contents of esters, alkenes, acids and ketone were found in 4 kGy group and the highest content of alcohol was detected in 6 kGy group. SDS-PAGE results showed that the degradation rate of sarcoplasmic and myofibrillar protein in irradiated fermented sausages were lower than control. (authors)

Recovery of fermented inulin fiber by lactic acid bacteria (LAB) from inulin hydrolysate using fungi inulinase enzymes of Scopulariopsis sp.-CBS1 and class of Deuteromycetes-CBS4 as cholesterol binder

Science.gov (United States)

Susilowati, Agustine; Melanie, Hakiki; Maryati, Yati; Aspiyanto

2017-01-01

Fermentation of Lactobacillus Acid Bacteria (LAB) which are mixtures of Lactobacillus acidophilus, Bifidobacteriumbifidum, Lactobacillus bulgaricus and Streptococcus thermophillus on hydrolysate as a result of inulin hydrolysis using inulinase enzymes obtained from endophytic fungi ofScopulariopsis sp.-CBS1 (inulin hydrolysate of S) and Class of Deuteromycetes-CBS4 (inulin hydrolysate of D) generate potential fermented inulin fiber as cholesterol binder. Fermentation process was conducted under concentrations of inulin hydrolysate 50% (w/v), LAB 15% (v/v) and skim milk 12.5% (w/v) at room temperature and 40°C for 0, 12, 24, 36 and 48 hours, respectively. Result of experimental work showed that longer time of LAB fermentation increased total acids, TPC and CBC at pH 2, but decreased total sugar, reducing, IDF, SDF, CBC pH 2 and CBC pH 7. Based on Cholesterol Binding Capacity (CBC), optimization of fermentation process on inulin hydrolysate of S was achieved by combining treatment at 40°C for 24 hours resulted in CBC pH 2 of 19.11 mg/g TDF and inulin hydrolysate of D was achieved by fermentation at 40 °C for 48 hours resulted in CBC pH 2 of 24.28 mg/g TDF. Inulin hydrolysate of class of Deutrymecetes CBS4 fermented by LAB had better functional property as cholesterol binder than that inulin hydrolysate of S fermented by LAB. This is due to cholesterol binder and cholesterol derivatives as a result of degradation of LAB on digestive system (stomach) when compared to higher colon under optimal process condition.

Electricity generation from fermented primary sludge using single-chamber air-cathode microbial fuel cells

KAUST Repository

Yang, Fei

2013-01-01

Single-chamber air-cathode microbial fuel cells (MFCs) were used to generate electricity from fermented primary sludge. Fermentation (30°C, 9days) decreased total suspended solids (26.1-16.5g/L), volatile suspended solids (24.1-15.3g/L) and pH (5.7-4.5), and increased conductivity (2.4-4.7mS/cm), soluble COD (2.66-15.5g/L), and volatile fatty acids (1.9-10.1g/L). To lower the COD and increase pH, fermentation supernatant was diluted with primary effluent before being used in the MFCs. The maximum power density was 0.32±0.01W/m2, compared to 0.24±0.03W/m2 with only primary effluent. Power densities were higher with phosphate buffer added to the supernatant (1.03±0.06W/m2) or the solution (0.87±0.05W/m2). Coulombic efficiencies ranged from 18% to 57%, and sCOD removals from 84% to 94%. These results demonstrated that sludge can effectively be used for power generation when fermented and then diluted with only primary effluent. © 2012 Elsevier Ltd.

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

Science.gov (United States)

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

2017-08-01

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

EFFECT OF TEMPERATURE ON THE PROCESS OF BEER PRIMARY FERMENTATION

OpenAIRE

Miriam Solgajová; Helena Frančáková; Štefan Dráb; Žigmund Tóth

2013-01-01

Beer is a very popular and widespread drink worldwide. Beer may be defined as a foamy alcoholic drink aerated by carbon dioxide that is formed during fermentation. Sensorial and analytical character of beer is mainly formed during process of primary fermentation. Our work has monitored the influence of temperature of fermentation substrate on the process of primary fermentation during beer production. Obtained values of temperature and apparent extract out of four brews of 10% light hopped wo...

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.

Ph influence on acidogenic dissimilation of glucose in an anaerobic digestor

Energy Technology Data Exchange (ETDEWEB)

Zoetemeyer, R J; van den Heuvel, J C; Cohen, A

1982-01-01

The paper describes a study of the influence of the pH value on acidogenesis, with reference to maximum specific growth rate and product distribution at various dilution rates, in order to optimize product distribution with respect to the more sensitive methanogenic stage. Glucose was used as the carbon-limiting substrate as its acidogenesis is rate limiting. 18 refs.

Effective extraction of cephalosporin C from whole fermentation ...

African Journals Online (AJOL)

The biphasic system was prepared by mixing equal aliquots of 15% w/w polyethylene glycol (PEG) 3350 with 15% (NH4)2SO4. The effects of pH, neutral salts, temperature and centrifugal force on partitioning in ATPS to develop efficient extraction system for recovery of CPC from fermentation broth were also examined.

Industrial yogurt manufacture: monitoring of fermentation process and improvement of final product quality.

Science.gov (United States)

Soukoulis, C; Panagiotidis, P; Koureli, R; Tzia, C

2007-06-01

Lactic acid fermentation during the production of skim milk and whole fat set-style yogurt was continuously monitored by measuring pH. The modified Gompertz model was successfully applied to describe the pH decline and viscosity development during the fermentation process. The viscosity and incubation time data were also fitted to linear models against ln(pH). The investigation of the yogurt quality improvement practices included 2 different heat treatments (80 degrees C for 30 min and 95 degrees C for 10 min), 3 milk protein fortifying agents (skim milk powder, whey powder, and milk protein concentrate) added at 2.0%, and 4 hydrocolloids (kappa-carrageenan, xanthan, guar gum, and pectin) added at 0.01% to whole fat and skim yogurts. Heat treatment significantly affected viscosity and acetaldehyde development without influencing incubation time and acidity. The addition of whey powder shortened the incubation time but had a detrimental effect on consistency, firmness, and overall acceptance of yogurts. On the other hand, addition of skim milk powder improved the textural quality and decreased the vulnerability of yogurts to syneresis. Anionic stabilizers (kappa-carrageenan and pectin) had a poor effect on the texture and palatability of yogurts. However, neutral gums (xanthan and guar gum) improved texture and prevented the wheying-off defect. Skim milk yogurts exhibited longer incubation times and higher viscosities, whereas they were rated higher during sensory evaluation than whole fat yogurts.

Demonstration-Scale High-Cell-Density Fermentation of Pichia pastoris.

Science.gov (United States)

Liu, Wan-Cang; Zhu, Ping

2018-01-01

Pichia pastoris has been one of the most successful heterologous overexpression systems in generating proteins for large-scale production through high-cell-density fermentation. However, optimizing conditions of the large-scale high-cell-density fermentation for biochemistry and industrialization is usually a laborious and time-consuming process. Furthermore, it is often difficult to produce authentic proteins in large quantities, which is a major obstacle for functional and structural features analysis and industrial application. For these reasons, we have developed a protocol for efficient demonstration-scale high-cell-density fermentation of P. pastoris, which employs a new methanol-feeding strategy-biomass-stat strategy and a strategy of increased air pressure instead of pure oxygen supplement. The protocol included three typical stages of glycerol batch fermentation (initial culture phase), glycerol fed-batch fermentation (biomass accumulation phase), and methanol fed-batch fermentation (induction phase), which allows direct online-monitoring of fermentation conditions, including broth pH, temperature, DO, anti-foam generation, and feeding of glycerol and methanol. Using this protocol, production of the recombinant β-xylosidase of Lentinula edodes origin in 1000-L scale fermentation can be up to ~900 mg/L or 9.4 mg/g cells (dry cell weight, intracellular expression), with the specific production rate and average specific production of 0.1 mg/g/h and 0.081 mg/g/h, respectively. The methodology described in this protocol can be easily transferred to other systems, and eligible to scale up for a large number of proteins used in either the scientific studies or commercial purposes.

The antioxidant activity of kombucha fermented milk products with stinging nettle and winter savory

Directory of Open Access Journals (Sweden)

Vitas Jasmina S.

2013-01-01

Full Text Available This paper investigates the antioxidant activity of fermented milk products obtained by kombucha fermentation. Two starter cultures were used as follows: starter obtained after kombucha fermentation on sweetened stinging nettle extract; as well as starter obtained after kombucha fermentation on sweetened winter savory extract. The starters were added to milk with 0.8, 1.6 and 2.8% milk fat. Fermentation was carried out at 37, 40 and 43oC and stopped when the pH reached 4.5. Antioxidant activity to hydroxyl and DPPH radicals was monitored using response surface methodology. Kombucha fermented milk products with stinging nettle (KSN and with winter savory (KWS showed the same antioxidant response to hydroxyl and different response to DPPH radicals. Synergetic effect of milk fat and fermentation temperature to antioxidant activity to hydroxyl radicals for both types of kombucha fermented milk products (KSN and KWS was established. Optimum processing conditions in term of antioxidant activity are: milk fat around 2.8% and process temperature around 41 and 43°C for KSN and KWS respectively.