FEED COMPONENT INHIBITION IN ETHANOLIC FERMENTATION BY SACCHAROMYCES-CEREVISIAE
FEED COMPONENT INHIBITION IN ETHANOLIC FERMENTATION BY SACCHAROMYCES-CEREVISIAE
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DOI：
10.1002/bit.260261004
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发表时间：
1984-01-01
影响因子：
3.8
通讯作者：
WILKE, CR
中科院分区：
文献类型：
--
作者：
MAIORELLA, BL;BLANCH, HW;WILKE, CR
二次饲料成分的抑制作用会限制生产效率，并限制通过发酵生产乙醇的工艺选择。新的发酵工艺（如真空或萃取发酵）在选择性去除乙醇的同时，可以将未代谢的饲料成分浓缩在剩余的肉汤中。为了减少废液处理而进行的废液回收会导致非代谢饲料成分的积累。通过连续培养实验确定了抑制顺序：CaCl2、（NH4）2SO4 > NaCl、NH4Cl > KH2PO4 >木糖、MgCl2 > MgSO4 > KCl。水活度的降低本身并不能充分预测不同成分间的抑菌浓度变化。作为一般趋势，随着抑制剂浓度的增加，特定乙醇产量增加，细胞产量下降。这些结果可以解释为在高渗（应激）条件下细胞维持的能量需求增加。离子和碳水化合物的运输和特定的毒性作用，因为它们与假设的抑制机制有关。高渗条件下甘油产量增加，甘油被认为是一种无毒的渗透调节剂。Ca是测试中最具抑制作用的成分，在0.23 mol Ca2+/l时导致细胞产量下降80%，并且Ca在许多碳水化合物来源中存在大量浓度。对于一种典型的最终甘蔗糖蜜饲料，静止液循环必须限制在饲料速率的1/3以下；否则将观察到抑制作用。
Inhibition by secondary feed components can limit productivity and restrict process options for the production of ethanol by fermentation. New fermentation processes (such as vacuum or extractive fermentation), while selectively removing ethanol, can concentrate nonmetabolized feed components in the remaining broth. Stillage recycle to reduce stillage waste treatment results in the buildup of nonmetabolized feed components. Continuous culture experiments were presented establishing an inhibition order: CaCl2, (NH4)2SO4 > NaCl, NH4Cl > KH2PO4 > xylose, MgCl2 > MgSO4 > KCl. Reduction of the water activity alone is not an adequate predictor of the variation in inhibitory concentration among the different components tested. As a general trend, specific ethanol productivity increases and cell production decreases as inhibitors are added at higher concentration. These results can be interpreted in terms of an increase in energy requirements for cell maintenance under hypertonic (stressed) conditions. Ion and carbohydrate transport and specific toxic effects were reviewed as they relate to the postulated inhibition mechanism. Glycerol production increases under hypertonic conditions and glycerol is postulated to function as a nontoxic osmoregulator. Ca was the most inhibitory component tested, causing an 80% decline in cell mass production at 0.23 mol Ca2+/l and Ca is present at substantial concentration in many carbohydrate sources. For a typical final cane molasses feed, stillage recycle must be limited to < 1/3 of the feed rate; otherwise inhibitory effects will be observed.