低甘油产率的酿酒酵母工程菌构建研究进展

Research Progress in Engineered Saccharomyces cerevisiae Construction With Low Yield of Glycerol

酿酒酵母具有安全、遗传背景清楚、生长速度快、高糖耐受性、高乙醇产量以及高胁迫耐受性等特性,是乙醇生产较为理想的细胞工厂。甘油是酿酒酵母发酵产乙醇过程中的一种主要伴生副产物,过量表达甘油影响糖醇转化率。通过基因工程改造甘油代谢和乙醇生产途径,是降低甘油产量和提高乙醇转化率的有效策略。首先分析改造酿酒酵母细胞中甘油和乙醇代谢路径,阐明甘油在酿酒酵母中生理功能;然后,根据甘油合成途径、分解途径和NAD^(+)/NADH代谢途径,分析低甘油产率的酿酒酵母工程菌构建的技术路径,比较各种基因改造策略对甘油合成和乙醇产率的影响;最后,针对基因整合技术、工程菌遗传稳定型以及工程菌代谢负担加重方面存在的问题,提出可供参考的解决方案,为构建酿酒酵母工程菌高效生产乙醇提供参考。

Saccharomyces cerevisiae is an ideal cell factory for ethanol production due to its safety, clear genetic background, fast growth, high sugar tolerance, high ethanol yield and high stress tolerance. Glycerol is one of the main by-products in ethanol production by S. cerevisiae. The overexpression of glycerol affects the conversion rate of sugar into alcohol. The modification of glycerol metabolism and ethanol production by genetic engineering is an effective strategy to reduce glycerol production and improve ethanol conversion. In this paper, the metabolic pathways of glycerol and ethanol in S. cerevisiae was firstly analyzed. The physiological function of glycerol in S. cerevisiae was elucidated. Then, the technological paths of genetically engineered S. cerevisiae construction with low glycerol yield were analyzed according to the glycerol synthesis, decomposition and NAD^(+)/NADH metabolic pathway. The effect of various genetic modification strategies on glycerol synthesis and ethanol yield was compared to analyze the mechanism of glycerol synthesis and ethanol yield. Finally, solutions for reference were put forward in term of existing problems of gene integration technology, genetic stability of engineering bacteria, metabolic burden of engineering bacteria. This paper can provide some reference for engineering S. cerevisiae construction for efficient production of ethanol.