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
Kefiran is an exopolysaccharide derived from kefir grains that has antioxidant and antimicrobial properties.The high production cost of kefiran is primarily attributed to the expensive fermentation media.Therefore,the...Kefiran is an exopolysaccharide derived from kefir grains that has antioxidant and antimicrobial properties.The high production cost of kefiran is primarily attributed to the expensive fermentation media.Therefore,the use of byproducts from agro-industries could present an economically favorable alternative.In this study,locally available mature coconut water(MCW)and whey lactose(WL)were used as cost-effective nutrient sources for kefiran production by Lactobacillus kefiranofaciens JCM 6985.MCW gave a higher yield of kefiran and acid than WL and was comparable to the commercial medium.The optimal sugar concentration for kefiran and acid production from MCW was 30 g/L,and the pH control during cultivation could alleviate the inhibitory effect of acidic pH and enhance kefiran and acid production.When the MCW was added with yeast extract at 3 g-nitrogen/L,the kefiran and acid production increased up to 3.26±0.03 g/L and 15.5±0.7 g/L,respectively.Moreover,the kefiran and acid production was scaled up in the bioreactor and enhanced by the repeated-batch cultivation for six cycles.The structure analysis indicated that kefiran produced by L.kefiranofaciens when using MCW had a similar structure to that extracted from kefir grains.The findings demonstrate promising methods for cost-effective production of kefiran and lactic acid using inexpensive nutrient sources such as MCW.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.
基金supported by Faculty of Agro-Industry and National Science,Research and Innovation Fund(NSRF)and Prince of Songkla University(Ref.No.AGR6601042a).
文摘Kefiran is an exopolysaccharide derived from kefir grains that has antioxidant and antimicrobial properties.The high production cost of kefiran is primarily attributed to the expensive fermentation media.Therefore,the use of byproducts from agro-industries could present an economically favorable alternative.In this study,locally available mature coconut water(MCW)and whey lactose(WL)were used as cost-effective nutrient sources for kefiran production by Lactobacillus kefiranofaciens JCM 6985.MCW gave a higher yield of kefiran and acid than WL and was comparable to the commercial medium.The optimal sugar concentration for kefiran and acid production from MCW was 30 g/L,and the pH control during cultivation could alleviate the inhibitory effect of acidic pH and enhance kefiran and acid production.When the MCW was added with yeast extract at 3 g-nitrogen/L,the kefiran and acid production increased up to 3.26±0.03 g/L and 15.5±0.7 g/L,respectively.Moreover,the kefiran and acid production was scaled up in the bioreactor and enhanced by the repeated-batch cultivation for six cycles.The structure analysis indicated that kefiran produced by L.kefiranofaciens when using MCW had a similar structure to that extracted from kefir grains.The findings demonstrate promising methods for cost-effective production of kefiran and lactic acid using inexpensive nutrient sources such as MCW.
