SCI和EI收录∣中国化工学会会刊

›› 2011, Vol. 19 ›› Issue (6): 1017-1022.

• BIOTECHNOLOGY AND BIOENGINEERING • Previous Articles     Next Articles

Medium Optimization for Improved Ethanol Production in Very High Gravity Fermentation

HU Chunkeng, QIN Qing, GAO Peipei   

  1. Department of Biological Engineering, School of Chemical Engineering, Huaqiao University, Xiamen 361021, China
  • Received:2010-07-26 Revised:2011-07-28 Online:2012-04-24 Published:2011-12-28
  • Supported by:
    Supported by the Natural Science Foundation of Fujian Province of China (E0810018)

Medium Optimization for Improved Ethanol Production in Very High Gravity Fermentation

胡纯铿, 秦晴, 高培培   

  1. Department of Biological Engineering, School of Chemical Engineering, Huaqiao University, Xiamen 361021, China
  • 通讯作者: HU Chunkeng, E-mail: ckhu@hqu.edu.cn
  • 基金资助:
    Supported by the Natural Science Foundation of Fujian Province of China (E0810018)

Abstract: An optimal medium (300 g·L-1 initial glucose) comprising 6.3 mmol·L-1 Mg2+, 5.0 mmol·L-1 Ca2+, 15.0 g·L-1 peptone and 21.5 g·L-1 yeast extract was determined by uniform design to improve very high gravity (VHG) ethanol fermentation, showing over 30% increase in final ethanol (from 13.1% to 17.1%, by volume), 29% decrease in fermentation time (from 84 to 60 h), 80% increase in biomass formation and 26% increase in glucose utilization. Experiments also revealed physiological aspects linked to the fermentation enhancements. Compared to the control, trehalose in the cells grown in optimal fermentation medium increased 17.9-, 2.8-, 1.9-, 1.8- and 1.9-fold at the fermentation time of 12, 24, 36, 48 and 60 h, respectively. Its sharp rise at the early stage of fermentation when there was a considerable osmotic stress suggested that trehalose played an important role in promoting fermentation. Meanwhile, at the identical five fermentation time, the plasma membrane ATPase activity of the cells grown in optimal medium was 2.3, 1.8, 1.6, 1.5 and 1.3 times that of the control, respectively. Their disparities in enzymatic activity became wider when the glucose levels were dramatically changed for ethanol production, suggesting this enzyme also contributed to the fermentation improvements. Thus, medium optimization for VHG ethanol fermentation was found to trigger the increased yeast trehalose accumulation and plasma membrane ATPase activity.

Key words: medium optimization, very high gravity fermentation, trehalose, plasma membrane ATPase

摘要: An optimal medium (300 g·L-1 initial glucose) comprising 6.3 mmol·L-1 Mg2+, 5.0 mmol·L-1 Ca2+, 15.0 g·L-1 peptone and 21.5 g·L-1 yeast extract was determined by uniform design to improve very high gravity (VHG) ethanol fermentation, showing over 30% increase in final ethanol (from 13.1% to 17.1%, by volume), 29% decrease in fermentation time (from 84 to 60 h), 80% increase in biomass formation and 26% increase in glucose utilization. Experiments also revealed physiological aspects linked to the fermentation enhancements. Compared to the control, trehalose in the cells grown in optimal fermentation medium increased 17.9-, 2.8-, 1.9-, 1.8- and 1.9-fold at the fermentation time of 12, 24, 36, 48 and 60 h, respectively. Its sharp rise at the early stage of fermentation when there was a considerable osmotic stress suggested that trehalose played an important role in promoting fermentation. Meanwhile, at the identical five fermentation time, the plasma membrane ATPase activity of the cells grown in optimal medium was 2.3, 1.8, 1.6, 1.5 and 1.3 times that of the control, respectively. Their disparities in enzymatic activity became wider when the glucose levels were dramatically changed for ethanol production, suggesting this enzyme also contributed to the fermentation improvements. Thus, medium optimization for VHG ethanol fermentation was found to trigger the increased yeast trehalose accumulation and plasma membrane ATPase activity.

关键词: medium optimization, very high gravity fermentation, trehalose, plasma membrane ATPase