Kinetics of glycerol production by fermentation with osmotolerant yeast Candida krusei was studied. Suppositions of cell negative effect on and glucose inhibition in specific growth rate and glycerol assumption for en...Kinetics of glycerol production by fermentation with osmotolerant yeast Candida krusei was studied. Suppositions of cell negative effect on and glucose inhibition in specific growth rate and glycerol assumption for energy maintenance were made. Based on the suppositions, a set of unstructured kinetic models including cell groWth, glucose consumption and glycerol accumulation rate was proposed. To avoid the significant decrease of produced glyccerol in the latter fermentation stage, the fermentation was suggested to be ended when the concentration ratio of glycerol to glucose is close to 7.展开更多
Nitrogen,one of the most crucial nutrients present in grapes and musts,plays a key role in yeast activities during alcoholic fermentation.Such influences are imposed on yeast growth and fermentation performances inclu...Nitrogen,one of the most crucial nutrients present in grapes and musts,plays a key role in yeast activities during alcoholic fermentation.Such influences are imposed on yeast growth and fermentation performances including the formation of secondary metabolites.Saccharomyces cerevisiae,the main yeast responsible for fermentation,has been studied extensively regarding nitrogen impacts.On the other hand,a similar study for non-Saccharomyces yeasts,whose contributions to winemaking have gradually been acknowledged,remains to be fully explored,with a few studies being reported.This review starts by discussing nitrogen impacts on non-Saccharomyces yeast growth and fermentation kinetics in different case scenarios,then proceeds to summarize the nitrogen preferences of individual yeast strains with regulation mechanisms elucidated by recent studies.Detailed discussions on the influences on the production of volatile compounds and proposed pathways therein are made,followed by future work suggested as the final section.In summarizing the nitrogen impacts on non-Saccharomyces yeasts throughout alcoholic fermentation,this review will be helpful in obtaining a more comprehensive view on these non-conventional wine yeasts in terms of nutrient requirements and corresponding volatile production.Research gaps will therefore be elucidated for future research.展开更多
In batch cultures of Candida krusei , the effect of corn steep liquor (CSL) concentration was investigated. The result showed that glycerol yield was greatly affected by CSL concentration. Higher glycerol yield was at...In batch cultures of Candida krusei , the effect of corn steep liquor (CSL) concentration was investigated. The result showed that glycerol yield was greatly affected by CSL concentration. Higher glycerol yield was attained when the initial CSL concentration in the medium was 9?g·L -1 . The fermentation kinetics were studied and the parameters for cell growth, maintenance, and glycerol production were obtained. Material balance revealed by product formation during the growth phase and suggested a fed-batch culture strategy.展开更多
Effects of periodic temperature variation on glycerol fermentation by osmophilic yeast was discussed.At the same time,glycerol fermentation by periodic temperature variation,constant temperature,aerating nitrogen or c...Effects of periodic temperature variation on glycerol fermentation by osmophilic yeast was discussed.At the same time,glycerol fermentation by periodic temperature variation,constant temperature,aerating nitrogen or carbon dioxide during the later stage were compared.The result showed that glycerol yield by periodic temperature variation fermentation was higher than that by constant temperature fermentation and an appropriate temperature oscillatory range was 35-45?℃.During the later stage of constant temperature fermentation,when fermentation time was 72?h,glycerol yield was the highest.After that,glycerol yield began to reduce and glycerol began to be consumed.Then,nitrogen gas or carbon dioxide was sparged in fermentation medium to ferment glycerol unceasingly,which can decrease residual sugar,increase glycerol yield further and avoid glycerol being consumed.Moreover,during the later stage of glycerol fermentation,glycerol yield by sparging nitrogen gas was higher than that by sparging carbon dioxide.展开更多
从酒精发酵的代谢机理出发,在引入酶动力学、提出联合抑制的可逆图解式后导得理论速率方程。依据实验对固定化 K 字酵母生物催化剂进行的酒精生成动力学之研究表明:该过程具有酒精的不可逆及表现为随其浓度而变化的非竞争型抑制,葡萄糖...从酒精发酵的代谢机理出发,在引入酶动力学、提出联合抑制的可逆图解式后导得理论速率方程。依据实验对固定化 K 字酵母生物催化剂进行的酒精生成动力学之研究表明:该过程具有酒精的不可逆及表现为随其浓度而变化的非竞争型抑制,葡萄糖则呈现为反竞争性抑制,及动力学参数随底物初始浓度变化等特性。提出的酒精生成动力学模型基础方程为联合抑制方程,所确定的参数值具有高度的相关性。且预测效果良好,其中酒精浓度随反应器高度分布的预测误差仅为18.75%,从而推知反应器内流体流动形式接近于平推流。展开更多
基金From National Ninth Five Years Project (NO. 96-03-03-03A).
文摘Kinetics of glycerol production by fermentation with osmotolerant yeast Candida krusei was studied. Suppositions of cell negative effect on and glucose inhibition in specific growth rate and glycerol assumption for energy maintenance were made. Based on the suppositions, a set of unstructured kinetic models including cell groWth, glucose consumption and glycerol accumulation rate was proposed. To avoid the significant decrease of produced glyccerol in the latter fermentation stage, the fermentation was suggested to be ended when the concentration ratio of glycerol to glucose is close to 7.
基金supported by grants from the National Natural Science Foundation of China(32172340)。
文摘Nitrogen,one of the most crucial nutrients present in grapes and musts,plays a key role in yeast activities during alcoholic fermentation.Such influences are imposed on yeast growth and fermentation performances including the formation of secondary metabolites.Saccharomyces cerevisiae,the main yeast responsible for fermentation,has been studied extensively regarding nitrogen impacts.On the other hand,a similar study for non-Saccharomyces yeasts,whose contributions to winemaking have gradually been acknowledged,remains to be fully explored,with a few studies being reported.This review starts by discussing nitrogen impacts on non-Saccharomyces yeast growth and fermentation kinetics in different case scenarios,then proceeds to summarize the nitrogen preferences of individual yeast strains with regulation mechanisms elucidated by recent studies.Detailed discussions on the influences on the production of volatile compounds and proposed pathways therein are made,followed by future work suggested as the final section.In summarizing the nitrogen impacts on non-Saccharomyces yeasts throughout alcoholic fermentation,this review will be helpful in obtaining a more comprehensive view on these non-conventional wine yeasts in terms of nutrient requirements and corresponding volatile production.Research gaps will therefore be elucidated for future research.
文摘In batch cultures of Candida krusei , the effect of corn steep liquor (CSL) concentration was investigated. The result showed that glycerol yield was greatly affected by CSL concentration. Higher glycerol yield was attained when the initial CSL concentration in the medium was 9?g·L -1 . The fermentation kinetics were studied and the parameters for cell growth, maintenance, and glycerol production were obtained. Material balance revealed by product formation during the growth phase and suggested a fed-batch culture strategy.
基金国家"九五"攻关项目 (No .96 -C0 3-0 3-0 3A)国家计委重点工业性实验项目资助
文摘Effects of periodic temperature variation on glycerol fermentation by osmophilic yeast was discussed.At the same time,glycerol fermentation by periodic temperature variation,constant temperature,aerating nitrogen or carbon dioxide during the later stage were compared.The result showed that glycerol yield by periodic temperature variation fermentation was higher than that by constant temperature fermentation and an appropriate temperature oscillatory range was 35-45?℃.During the later stage of constant temperature fermentation,when fermentation time was 72?h,glycerol yield was the highest.After that,glycerol yield began to reduce and glycerol began to be consumed.Then,nitrogen gas or carbon dioxide was sparged in fermentation medium to ferment glycerol unceasingly,which can decrease residual sugar,increase glycerol yield further and avoid glycerol being consumed.Moreover,during the later stage of glycerol fermentation,glycerol yield by sparging nitrogen gas was higher than that by sparging carbon dioxide.
文摘从酒精发酵的代谢机理出发,在引入酶动力学、提出联合抑制的可逆图解式后导得理论速率方程。依据实验对固定化 K 字酵母生物催化剂进行的酒精生成动力学之研究表明:该过程具有酒精的不可逆及表现为随其浓度而变化的非竞争型抑制,葡萄糖则呈现为反竞争性抑制,及动力学参数随底物初始浓度变化等特性。提出的酒精生成动力学模型基础方程为联合抑制方程,所确定的参数值具有高度的相关性。且预测效果良好,其中酒精浓度随反应器高度分布的预测误差仅为18.75%,从而推知反应器内流体流动形式接近于平推流。
