To improve the efficiency of ethanol production in a batch fermentation from sweet sorghum juice under a very high gravity(VHG)condition(~290 g/L of total sugar)by Saccharomyces cerevisiae NP01,repeatedbatch fermentat...To improve the efficiency of ethanol production in a batch fermentation from sweet sorghum juice under a very high gravity(VHG)condition(~290 g/L of total sugar)by Saccharomyces cerevisiae NP01,repeatedbatch fermentation under an aerated condition(2.5 vvm for the first 4 h during every cycle)was done in a5-L fermenter.The average ethanol concentration(P),productivity(Qp)and yield(Yp/s)for five successive cycles were 112.31 g/L,1.55 g/L·h^-1 and 0.44,respectively with 80.97%sugar consumption.To complete sugar consumption,the total sugar of the juice was reduced to a high gravity(HG)level(~240 g/L).The results showed that yeast extract was not necessary for ethanol production,and aeration during every other cycle i.e.,alternating cycles,was sufficient to promote both yeast growth and ethanol production.The average P,Qpand Yp/svalues for eight successive cycles with aeration during alternating cycles were97.58 g/L,1.98 g/Láh and 0.41,respectively with 91.21%sugar consumption.The total fatty acids in the yeast cells under the aerated condition were^50%higher than without aeration,irrespective the initial sugar concentration,whereas the ergosterol contents under aeration condition were^29%to 49%higher than those without aeration.展开更多
Glycerol production by repeated batch fermentation of Candida glycerinogenes was studied by using not only synthetic medium but also complex medium.The results showed that the increase rates of glycerol production,gly...Glycerol production by repeated batch fermentation of Candida glycerinogenes was studied by using not only synthetic medium but also complex medium.The results showed that the increase rates of glycerol production,glycerol yield on initial glucose and glycerol productivity were beyond 15.0%,15.0% and 37.0% when yeast cells are recycled 13 times in low phosphate synthetic medium,9 times in low phosphate complex medium and 14 times in low phosphate complex medium with supplemented trace elements,respectively.The number of recycling in low phosphate complex medium was fewer than that in low phosphate synthetic medium.It is because low phosphate synthetic medium only limited phosphate concentration,while low phosphate complex medium limited both trace elements and phosphate.The shortage of trace elements solution influenced cell growth and glycerol synthesis,and reduced recycling number of yeast cells in low phosphate complex medium.The limitation of phosphate concentration in repeated batch fermentation medium was helpful to promoting the ability of glycerol synthesis of C.glycerinogenes.展开更多
基金Supported by the Post-Doctoral Training Program from Research Affairs and Graduate School,Khon Kaen University(KKU).Thailand(Grant no.59153)
文摘To improve the efficiency of ethanol production in a batch fermentation from sweet sorghum juice under a very high gravity(VHG)condition(~290 g/L of total sugar)by Saccharomyces cerevisiae NP01,repeatedbatch fermentation under an aerated condition(2.5 vvm for the first 4 h during every cycle)was done in a5-L fermenter.The average ethanol concentration(P),productivity(Qp)and yield(Yp/s)for five successive cycles were 112.31 g/L,1.55 g/L·h^-1 and 0.44,respectively with 80.97%sugar consumption.To complete sugar consumption,the total sugar of the juice was reduced to a high gravity(HG)level(~240 g/L).The results showed that yeast extract was not necessary for ethanol production,and aeration during every other cycle i.e.,alternating cycles,was sufficient to promote both yeast growth and ethanol production.The average P,Qpand Yp/svalues for eight successive cycles with aeration during alternating cycles were97.58 g/L,1.98 g/Láh and 0.41,respectively with 91.21%sugar consumption.The total fatty acids in the yeast cells under the aerated condition were^50%higher than without aeration,irrespective the initial sugar concentration,whereas the ergosterol contents under aeration condition were^29%to 49%higher than those without aeration.
文摘Glycerol production by repeated batch fermentation of Candida glycerinogenes was studied by using not only synthetic medium but also complex medium.The results showed that the increase rates of glycerol production,glycerol yield on initial glucose and glycerol productivity were beyond 15.0%,15.0% and 37.0% when yeast cells are recycled 13 times in low phosphate synthetic medium,9 times in low phosphate complex medium and 14 times in low phosphate complex medium with supplemented trace elements,respectively.The number of recycling in low phosphate complex medium was fewer than that in low phosphate synthetic medium.It is because low phosphate synthetic medium only limited phosphate concentration,while low phosphate complex medium limited both trace elements and phosphate.The shortage of trace elements solution influenced cell growth and glycerol synthesis,and reduced recycling number of yeast cells in low phosphate complex medium.The limitation of phosphate concentration in repeated batch fermentation medium was helpful to promoting the ability of glycerol synthesis of C.glycerinogenes.
