Decreasing acetic acid accumulation by a glycerol overproducing strain of Saccharomyces cerevisiae by deleting the ALD6 aldehyde dehydrogenase gene
Decreasing acetic acid accumulation by a glycerol overproducing strain of Saccharomyces cerevisiae by deleting the ALD6 aldehyde dehydrogenase gene
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作者：
Eglinton, JM;Heinrich, AJ;Lopes, MD
甘油是酿酒酵母的主要发酵产物，对葡萄酒的感官特性有重要影响。通过过度表达甘油3-磷酸脱氢酶基因GPD 2，将糖过度转化为甘油，而不生产乙醇，导致S。在厌氧细胞培养中，酿酒酵母产生的乙酸是野生型菌株（S288 C背景）的两倍多。在野生型和GPD 2过表达菌株（GPD 2-OP）中，醛脱氢酶基因ALD 6的缺失分别使乙酸产量降低了3倍和4倍。与减少的乙酸产生相结合，GPD 2-OP ald 6 Delta菌株比野生型产生更多的甘油和更少的乙醇。修饰的和野生型菌株的生长速率和发酵速率是相似的，尽管从24小时开始GPD 2 ald 6 Delta菌株的发酵速率略低于其它菌株。对突变体的代谢组学分析表明，基因修饰影响了发酵过程中一些次级代谢产物的产生，包括酸、酯、醛和高级醇，其中许多在葡萄酒中具有风味活性。GPD 2和ALD 6表达的修饰代表了在发酵期间增加甘油和降低乙醇浓度的有效策略，并且改变了培养基的化学组成，使得潜在的新风味多样性成为可能。在商业葡萄酒生产中使用这些修改的影响，需要在葡萄酒酵母菌株进一步调查。版权所有（C）2002约翰威利父子有限公司
Glycerol is a major fermentation product of Saccharomyces cerevisiae that contributes to the sensory character of wine. Diverting sugar to glycerol overproduction and away from ethanol production by overexpressing the glycerol 3-phosphate dehydrogenase gene, GPD2, caused S. cerevisiae to produce more than twice as much acetic acid as the wild-type strain (S288C background) in anaerobic cell culture. Deletion of the aldehyde dehydrogenase gene, ALD6, in wild-type and GPD2 overexpressing strains (GPD2-OP) decreased acetic acid production by three- and four-fold, respectively. In conjunction with reduced acetic acid production, the GPD2-OP ald6Delta strain produced more glycerol and less ethanol than the wild-type. The growth rate and fermentation rate were similar for the modified and wild-type strains, although the fermentation rate for the GPD2 ald6Delta strain was slightly less than that of the other strains from, 24 h onwards. Analysis of the metabolome of the mutants revealed that genetic modification affected the production of some secondary, metabolites of fermentation, including acids, esters, aldehydes and higher alcohols, many of which are flavour-active in wine. Modification of GPD2 and ALD6 expression represents an effective strategy to increase the glycerol and decrease the ethanol concentration during fermentation, and alters the chemical composition of the medium such that, potentially, novel flavour diversity, is possible. The implications for the use of these modifications in commercial wine production require further investigation in wine yeast strains. Copyright (C) 2002 John Wiley Sons, Ltd.