This research focused using novel substrate, longan Lactobacillus casei subsp, rhamnosus TISTR 108. The optimum juice as carbon source for continuous lactic acid production by medium for lactic acid production was pur...This research focused using novel substrate, longan Lactobacillus casei subsp, rhamnosus TISTR 108. The optimum juice as carbon source for continuous lactic acid production by medium for lactic acid production was pure longan juice with 120 g/L sugar concentration and among the different nitrogen sources were added to the longan juice （yeast extract, tryptic soy, urea, （NH4）2SO4 and NaNO3）, yeast extract had the most efficiency. Yeast extract （10 g/L） without adding minerals to longan juice could produced the maximum lactic acid concentration of 38.91 ± 0.190 g/L in 60 h and the yield of 0.460± 0.122 g/g with the productivity of 0.649± 0.002 g/Lh in 2 liters flask. Batch fermentation was conducted in 2 liters fermentor and 41.38± 0.030 g/L lactic acid was produced in 48 h with the yield of 0.398 ± 0.215 g/g and the productivity was 0.862 ± 0.001 g/L h. The continuous fermentation using 2 liters fermentor as a high productivity for lactic acid （1.091 ± 0.001 g/L h） was achieved at dilution rate （D） of 0.0685 h-1.展开更多
Using lignite samples, selected from Zhaotong basin, Yunnan province, China, as the parent source, simulating experiments of lignite biogas were conducted with 0.1% methanol, 5 mg/L yeast extract and 0.2 mol/L sodium ...Using lignite samples, selected from Zhaotong basin, Yunnan province, China, as the parent source, simulating experiments of lignite biogas were conducted with 0.1% methanol, 5 mg/L yeast extract and 0.2 mol/L sodium acetate solutions as the exogenous substance respectively. Variation characteristics of gas production, gas composition, VFA content and activity of coenzyme 1：42o in the simulated process were analyzed to discuss the influence of different substrates on lignite biogas generation. The results show that 0.1% methanol and 5 mg/L yeast extract solutions increase VFA contents in the biogas generation system （p 〈 0.05） and inhibit coenzyme F420 and methanogen activities significantly, so they decrease both gas amounts （p 〈 0.05） and CH4 contents （p 〈 0.05）. 0.2 mol/L sodium acetate solution activates coenzyme F42o and methanogen activities and improves the efficiency of enzymatic reaction, so the gas quantity （p 〈 0.05） and the CH4 content （p 〈 0.01） increase significantly. Therefore, sodium acetate can be one kind of good exogenous substance for the generation of lignite biogenic gas.展开更多
The growth ofCandida utilis NRRL Y-1084 in acid and enzymatic hydrolysates of cassava peel and on glucose in a mineral salts medium was investigated in aerobic submerged cultivation. Kinetic and stoichiometric paramet...The growth ofCandida utilis NRRL Y-1084 in acid and enzymatic hydrolysates of cassava peel and on glucose in a mineral salts medium was investigated in aerobic submerged cultivation. Kinetic and stoichiometric parameters for growth were determined. The cardinal temperatures of this yeast strain were 14 ℃, 33 ℃ and 41 ℃. C. utilis exhibited no absolute requirement for growth factors, although its maximum specific growth rate （μmax） was higher in the mineral salts medium with yeast extract than without, but its biomass yield coefficient （Yx/s） did not differ much in these two media. In the enzymatic hydrolysate, its Yx/s value on sugar was 0.44 with a μmax of 0.35 h^-1, whereas the corresponding values were 0.52 and 0.48 h^-1 in the acid hydrolysate and 0.50 and 0.37 h^-1 in the mineral salts medium without yeast extract. The crude protein content of biomass grown in the glucose medium and the acid and enzymatic hydrolysates were 47.5%, 49.1% and 56.7%, respectively. The amino acid profile of the yeast biomass compared favourably with the FAO standard. Cassava peel hydrolysate has potential as a cheap carbohydrate feedstock for the production of yeast single cell protein by using C. utilis.展开更多
Forty eight individually fed Awassi male lambs were used in factorial experiment to investigate their responses to feeding concentrate diets containing three levels of dietary crude protein （CP）, each was offered wi...Forty eight individually fed Awassi male lambs were used in factorial experiment to investigate their responses to feeding concentrate diets containing three levels of dietary crude protein （CP）, each was offered without or with baker＇s yeast （SC） at rate of 0.5% （on dry matter （DM） basis）. Concentrates were offered at rate of 3% of live body weight with free choice of barley straw. Results revealed that higher （P 〈 0.05） digestible dry matter （DDM） and digestible organic matter （DOM） intakes were achieved due to feeding medium level of CP and to the addition of SC. Addition of SC improved （P 〈 0.05） gain, lambs fed medium and high levels gained higher （P 〈 0.05） than those fed the low level of dietary CP. Feed conversion ratio （FCR） based on DM and organic matter （OM） intakes was not significantly affected by level of dietary CP or addition of yeast. Even though, less amount of N required per unit of gain was achieved with low and medium as compared to high levels. Higher DM, nitrogen free extract （NFE） and hemicellulose （P 〈 0.05）, OM, CP, crude fiber （CF） and cellulose （P 〈 0.01） digestibilities were achieved in lambs fed the medium level of CP, whereas, no significant effect was observed on ether extract （EE）, neutral detergent fiber （NDF） and acid detergent fiber （ADF） digestibilities. Results also revealed that digestibility of almost all nutrients was improved with different extent due to addition of SC. Effect of interaction between levels of dietary CP and addition of SC referred to the preferability of addition of SC with medium level of dietary protein.展开更多
Due to the scarcity of fossil fuels in the world, there is increasing interest in the commercial production of biodiesel, which leads to obtaining large amounts of glycerol as a byproduct. If not disposed of properly,...Due to the scarcity of fossil fuels in the world, there is increasing interest in the commercial production of biodiesel, which leads to obtaining large amounts of glycerol as a byproduct. If not disposed of properly, glycerol can generate environmental impact. One of the promises, the application of the crude glycerol is the production of citric acid by microbial fermentation. Citric acid is industrially produced by a submerged fermentation process with Aspergillus niger, using sucrose as carbon source, but due to increased demand for citric acid, alternative processes using renewable sources or waste materials as substrates and the cultivation of yeast strains are being studied. The aim of the study was to determine the best culture condition for maximum citric acid synthesis and lower isocitric acid production from crude glycerol through experimental design tool. For this purpose, the yeast strain Yarrowia lipolytica IMUFRJ-50682 was cultivated in nitrogen-limited glycerol-based media. Therefore, glycerol and yeast extract concentrations and agitation speed were evaluated as independent variables. With pure glycerol, the highest citric acid production achieved was 16.5 g/L with an isocitric acid production of 7.7% （in relation to citric acid）. With crude glycerol, citric acid production reduced to 6.7 g/L because of higher biomass yield. Therefore, an increase in the initial carbon to nitrogen molar ratio from 714 to 1,561 was necessary to increase citric acid production to 9.2 g/L, reducing isocitric acid production and to achieve a yield of 0.41 g of citric acid per glycerol consumed. In this condition, less nitrogen source was used, reducing production costs.展开更多
Biologically produced surfactants （SACs） can mobilize and solubilize non-aqueous phase liquids （NAPL） adsorbed onto soil constituents. The interest in microbial surfactants has increased during recent years due to...Biologically produced surfactants （SACs） can mobilize and solubilize non-aqueous phase liquids （NAPL） adsorbed onto soil constituents. The interest in microbial surfactants has increased during recent years due to their lower toxicity, higher biodegradability, selectivity and specific activity under extreme conditions than synthetic SACs. Main output of the project represents preparation of this yeast biosurfactant intended for washing of matrices contaminated by NAPL. The influence of cultivation media composition on biosurfactant production was studied and basic properties （critical micelle concentration （CMC）, minimum surface tension） of isolated biosurfactants were compared with properties of synthetic surfactant with surface tension measurement. The interracial tension of the systems containing aqueous solutions of different concentrations and non-polar substances was measured with petroleum compounds （kerosene Jet A-l）, aromatic and aliphatic hydrocarbons （represented by toluene and hexane）. The solution of biosurfactant Yarrowia lipolytica （YAR） in the concentration range of 0-500 mg/L reduced interracial tension by 80% in all representative systems with model contaminants; biosurfactant Candida bombicola （CAN） was less efficient. Solubilization properties were proved with toluene and hexachlorocyclohexane （HCH） isomers alpha and gamma, and effective concentration of biosurfactants was determined as 100 mg/L for toluene and HCH. SACs produced by lipophilic yeast with non-toxic and non-pathogenic status （Yarrowia lipolytica, Candida sp., etc.） seem to be very promising. The results obtained will be used for the application of biosurfactants in the clean-up technologies as agents for the mobilization of non-polar contaminants as well as for stimulation of bioremediation processes.展开更多
The goal of this study was to evaluate the effects of a mixture of yeast culture, cell wall hydrolysates, and yeast extracts（collectively ＂yeast products,＂ YP） on the performance, intestinal physiology, and health...The goal of this study was to evaluate the effects of a mixture of yeast culture, cell wall hydrolysates, and yeast extracts（collectively ＂yeast products,＂ YP） on the performance, intestinal physiology, and health of weaned piglets. A total of 90 piglets weaned at 21 d of age were blocked by body weight, sex, and litter and randomly assigned to one of three treatments for a 14-d feeding experiment, including（1） a basal diet（control）,（2） 1.2 g/kg of YP, and（3） 20 mg/kg of colistin sulfate（CSE）. No statistically significant differences were observed in average daily feed intake, average daily weight gain, or gain-to-feed ratio among CSE, YP, and control piglets. Increased prevalence of diarrhea was observed among piglets fed the YP diet, whereas diarrhea was less prevalent among those fed CSE. Duodenal and jejunal villus height and duodenal crypt depth were greater in the control group than they were in the YP or CSE groups. Intraepithelial lymphocytes（IEL） in the duodenal and jejunal villi were enhanced by YP, whereas IEL in the ileal villi were reduced in weaned piglets fed YP. Secretion of jejunal and ileal interleukin-10（IL-10） was higher and intestinal and serum antioxidant indexes were affected by YP and CSE. In YP- and CSE-supplemented animals, serum D-lactate concentration and diamine oxidase（DAO） activity were both increased, and intestinal mR NA expressions of occludin and ZO-1 were reduced as compared to the control animals. In conclusion, YP supplementation in the diets of weaned piglets appears to increase the incidence of diarrhea and has adverse effects on intestinal morphology and barrier function.展开更多
The presence of yeast cells could stimulate hydrogen utilization of acetogens and enhance acetogenesis. To understand the roles of acetogens in rumen fermentation, an in vitro rumen fermentation experiment was conduct...The presence of yeast cells could stimulate hydrogen utilization of acetogens and enhance acetogenesis. To understand the roles of acetogens in rumen fermentation, an in vitro rumen fermentation experiment was conducted with addition of acetogen strain （TWA4） and/or Saccharomyces cerevisiae fermentation product （XP）. A 2×2 factorial design with two levels of TWA4 （0 or 2×10^7 cells/ml） and XP （0 or 2 g/L） was performed. Volatile fatty acids （VFAs） were increased （P〈0.05） in XP and TWA4XP, while methane was increased only in TWA4XP （P〈0.05）. The increase rate of microorganisms with formyltetrahydrofolate synthetase, especially acetogens, was higher than that of methanogens under all treatments. Lachnospiraceae was predominant in all acetogen communities, but without close acetyI-CoA synthase （ACS） amino acid sequences from cultured isolates. Low-Acetitomaculum ruminis-like ACS was predominant in all acetogen communities, while four unique phylotypes in XP treatment were all amino acid identified Iow-Eubacterium limosum-like acetogens. It differs to XP treatment that more Iow-A. ruminis-like and less Iow- E. limosum-like sequences were identified in ＂I＇WA4 and TWA4XP treatments. Enhancing acetogenesis by supple- mentation with an acetogen strain and/or yeast cells may be an approach to mitigate methane, by targeting proper acetogens such as uncultured Iow-E. limosum-like acetogens.展开更多
文摘This research focused using novel substrate, longan Lactobacillus casei subsp, rhamnosus TISTR 108. The optimum juice as carbon source for continuous lactic acid production by medium for lactic acid production was pure longan juice with 120 g/L sugar concentration and among the different nitrogen sources were added to the longan juice （yeast extract, tryptic soy, urea, （NH4）2SO4 and NaNO3）, yeast extract had the most efficiency. Yeast extract （10 g/L） without adding minerals to longan juice could produced the maximum lactic acid concentration of 38.91 ± 0.190 g/L in 60 h and the yield of 0.460± 0.122 g/g with the productivity of 0.649± 0.002 g/Lh in 2 liters flask. Batch fermentation was conducted in 2 liters fermentor and 41.38± 0.030 g/L lactic acid was produced in 48 h with the yield of 0.398 ± 0.215 g/g and the productivity was 0.862 ± 0.001 g/L h. The continuous fermentation using 2 liters fermentor as a high productivity for lactic acid （1.091 ± 0.001 g/L h） was achieved at dilution rate （D） of 0.0685 h-1.
基金supported by the National Natural Science Key Foundation of China (Nos. 41202119 and 41272177)the National Natural Science Key Foundation of China (No. 41202237)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Using lignite samples, selected from Zhaotong basin, Yunnan province, China, as the parent source, simulating experiments of lignite biogas were conducted with 0.1% methanol, 5 mg/L yeast extract and 0.2 mol/L sodium acetate solutions as the exogenous substance respectively. Variation characteristics of gas production, gas composition, VFA content and activity of coenzyme 1：42o in the simulated process were analyzed to discuss the influence of different substrates on lignite biogas generation. The results show that 0.1% methanol and 5 mg/L yeast extract solutions increase VFA contents in the biogas generation system （p 〈 0.05） and inhibit coenzyme F420 and methanogen activities significantly, so they decrease both gas amounts （p 〈 0.05） and CH4 contents （p 〈 0.05）. 0.2 mol/L sodium acetate solution activates coenzyme F42o and methanogen activities and improves the efficiency of enzymatic reaction, so the gas quantity （p 〈 0.05） and the CH4 content （p 〈 0.01） increase significantly. Therefore, sodium acetate can be one kind of good exogenous substance for the generation of lignite biogenic gas.
文摘The growth ofCandida utilis NRRL Y-1084 in acid and enzymatic hydrolysates of cassava peel and on glucose in a mineral salts medium was investigated in aerobic submerged cultivation. Kinetic and stoichiometric parameters for growth were determined. The cardinal temperatures of this yeast strain were 14 ℃, 33 ℃ and 41 ℃. C. utilis exhibited no absolute requirement for growth factors, although its maximum specific growth rate （μmax） was higher in the mineral salts medium with yeast extract than without, but its biomass yield coefficient （Yx/s） did not differ much in these two media. In the enzymatic hydrolysate, its Yx/s value on sugar was 0.44 with a μmax of 0.35 h^-1, whereas the corresponding values were 0.52 and 0.48 h^-1 in the acid hydrolysate and 0.50 and 0.37 h^-1 in the mineral salts medium without yeast extract. The crude protein content of biomass grown in the glucose medium and the acid and enzymatic hydrolysates were 47.5%, 49.1% and 56.7%, respectively. The amino acid profile of the yeast biomass compared favourably with the FAO standard. Cassava peel hydrolysate has potential as a cheap carbohydrate feedstock for the production of yeast single cell protein by using C. utilis.
文摘Forty eight individually fed Awassi male lambs were used in factorial experiment to investigate their responses to feeding concentrate diets containing three levels of dietary crude protein （CP）, each was offered without or with baker＇s yeast （SC） at rate of 0.5% （on dry matter （DM） basis）. Concentrates were offered at rate of 3% of live body weight with free choice of barley straw. Results revealed that higher （P 〈 0.05） digestible dry matter （DDM） and digestible organic matter （DOM） intakes were achieved due to feeding medium level of CP and to the addition of SC. Addition of SC improved （P 〈 0.05） gain, lambs fed medium and high levels gained higher （P 〈 0.05） than those fed the low level of dietary CP. Feed conversion ratio （FCR） based on DM and organic matter （OM） intakes was not significantly affected by level of dietary CP or addition of yeast. Even though, less amount of N required per unit of gain was achieved with low and medium as compared to high levels. Higher DM, nitrogen free extract （NFE） and hemicellulose （P 〈 0.05）, OM, CP, crude fiber （CF） and cellulose （P 〈 0.01） digestibilities were achieved in lambs fed the medium level of CP, whereas, no significant effect was observed on ether extract （EE）, neutral detergent fiber （NDF） and acid detergent fiber （ADF） digestibilities. Results also revealed that digestibility of almost all nutrients was improved with different extent due to addition of SC. Effect of interaction between levels of dietary CP and addition of SC referred to the preferability of addition of SC with medium level of dietary protein.
文摘Due to the scarcity of fossil fuels in the world, there is increasing interest in the commercial production of biodiesel, which leads to obtaining large amounts of glycerol as a byproduct. If not disposed of properly, glycerol can generate environmental impact. One of the promises, the application of the crude glycerol is the production of citric acid by microbial fermentation. Citric acid is industrially produced by a submerged fermentation process with Aspergillus niger, using sucrose as carbon source, but due to increased demand for citric acid, alternative processes using renewable sources or waste materials as substrates and the cultivation of yeast strains are being studied. The aim of the study was to determine the best culture condition for maximum citric acid synthesis and lower isocitric acid production from crude glycerol through experimental design tool. For this purpose, the yeast strain Yarrowia lipolytica IMUFRJ-50682 was cultivated in nitrogen-limited glycerol-based media. Therefore, glycerol and yeast extract concentrations and agitation speed were evaluated as independent variables. With pure glycerol, the highest citric acid production achieved was 16.5 g/L with an isocitric acid production of 7.7% （in relation to citric acid）. With crude glycerol, citric acid production reduced to 6.7 g/L because of higher biomass yield. Therefore, an increase in the initial carbon to nitrogen molar ratio from 714 to 1,561 was necessary to increase citric acid production to 9.2 g/L, reducing isocitric acid production and to achieve a yield of 0.41 g of citric acid per glycerol consumed. In this condition, less nitrogen source was used, reducing production costs.
文摘Biologically produced surfactants （SACs） can mobilize and solubilize non-aqueous phase liquids （NAPL） adsorbed onto soil constituents. The interest in microbial surfactants has increased during recent years due to their lower toxicity, higher biodegradability, selectivity and specific activity under extreme conditions than synthetic SACs. Main output of the project represents preparation of this yeast biosurfactant intended for washing of matrices contaminated by NAPL. The influence of cultivation media composition on biosurfactant production was studied and basic properties （critical micelle concentration （CMC）, minimum surface tension） of isolated biosurfactants were compared with properties of synthetic surfactant with surface tension measurement. The interracial tension of the systems containing aqueous solutions of different concentrations and non-polar substances was measured with petroleum compounds （kerosene Jet A-l）, aromatic and aliphatic hydrocarbons （represented by toluene and hexane）. The solution of biosurfactant Yarrowia lipolytica （YAR） in the concentration range of 0-500 mg/L reduced interracial tension by 80% in all representative systems with model contaminants; biosurfactant Candida bombicola （CAN） was less efficient. Solubilization properties were proved with toluene and hexachlorocyclohexane （HCH） isomers alpha and gamma, and effective concentration of biosurfactants was determined as 100 mg/L for toluene and HCH. SACs produced by lipophilic yeast with non-toxic and non-pathogenic status （Yarrowia lipolytica, Candida sp., etc.） seem to be very promising. The results obtained will be used for the application of biosurfactants in the clean-up technologies as agents for the mobilization of non-polar contaminants as well as for stimulation of bioremediation processes.
基金supported by the National Natural Science Foundation of China(Nos.31330075,31402089,31301988,31572420,31272450,and 31272451)the National Key Technology R&D Program of China(No.2016YFD0500504)+2 种基金the Changsha Lvye Biotechnology Limited Company Academician Expert Workstationthe Guangdong Hinapharm Group Academician Workstation for Biological Feed and Feed Additivesthe Animal Intestinal Health Hunan New Wellful Co.,Ltd.,Academician Workstation,Changsha,China
文摘The goal of this study was to evaluate the effects of a mixture of yeast culture, cell wall hydrolysates, and yeast extracts（collectively ＂yeast products,＂ YP） on the performance, intestinal physiology, and health of weaned piglets. A total of 90 piglets weaned at 21 d of age were blocked by body weight, sex, and litter and randomly assigned to one of three treatments for a 14-d feeding experiment, including（1） a basal diet（control）,（2） 1.2 g/kg of YP, and（3） 20 mg/kg of colistin sulfate（CSE）. No statistically significant differences were observed in average daily feed intake, average daily weight gain, or gain-to-feed ratio among CSE, YP, and control piglets. Increased prevalence of diarrhea was observed among piglets fed the YP diet, whereas diarrhea was less prevalent among those fed CSE. Duodenal and jejunal villus height and duodenal crypt depth were greater in the control group than they were in the YP or CSE groups. Intraepithelial lymphocytes（IEL） in the duodenal and jejunal villi were enhanced by YP, whereas IEL in the ileal villi were reduced in weaned piglets fed YP. Secretion of jejunal and ileal interleukin-10（IL-10） was higher and intestinal and serum antioxidant indexes were affected by YP and CSE. In YP- and CSE-supplemented animals, serum D-lactate concentration and diamine oxidase（DAO） activity were both increased, and intestinal mR NA expressions of occludin and ZO-1 were reduced as compared to the control animals. In conclusion, YP supplementation in the diets of weaned piglets appears to increase the incidence of diarrhea and has adverse effects on intestinal morphology and barrier function.
基金supported by the Fundamental Research Funds for the Central Universities(No.2011XZZX006)the National Natural Science Foundation of China(No.31172229)the University of Alberta Research Internship Program Summer 2012,Canada
文摘The presence of yeast cells could stimulate hydrogen utilization of acetogens and enhance acetogenesis. To understand the roles of acetogens in rumen fermentation, an in vitro rumen fermentation experiment was conducted with addition of acetogen strain （TWA4） and/or Saccharomyces cerevisiae fermentation product （XP）. A 2×2 factorial design with two levels of TWA4 （0 or 2×10^7 cells/ml） and XP （0 or 2 g/L） was performed. Volatile fatty acids （VFAs） were increased （P〈0.05） in XP and TWA4XP, while methane was increased only in TWA4XP （P〈0.05）. The increase rate of microorganisms with formyltetrahydrofolate synthetase, especially acetogens, was higher than that of methanogens under all treatments. Lachnospiraceae was predominant in all acetogen communities, but without close acetyI-CoA synthase （ACS） amino acid sequences from cultured isolates. Low-Acetitomaculum ruminis-like ACS was predominant in all acetogen communities, while four unique phylotypes in XP treatment were all amino acid identified Iow-Eubacterium limosum-like acetogens. It differs to XP treatment that more Iow-A. ruminis-like and less Iow- E. limosum-like sequences were identified in ＂I＇WA4 and TWA4XP treatments. Enhancing acetogenesis by supple- mentation with an acetogen strain and/or yeast cells may be an approach to mitigate methane, by targeting proper acetogens such as uncultured Iow-E. limosum-like acetogens.
