分别利用产甘油假丝酵母抗逆转录因子CgSTB5和CgSEF1对酿酒酵母菌株糠醛耐受改造

Enhance Saccharomyces cerevisiae furfural tolerance by the introduction of Candida glycerinogenes transcription factors CgSTB5 or CgSEF1

摘要:

[背景] 纤维素是生物转化解决能源问题的主要原料之一，其水解物中存在严重影响抑制菌株生长的糠醛，需脱毒才可应用于发酵，提高菌株耐受性是解决纤维素水解液实际生产应用的关键。[目的] 酿酒酵母（Saccharomyces cerevisiae）是主要的纤维素水解液发酵工业菌株，但糠醛耐受性较低，通过分子改造获得具有高糠醛耐受性的菌株。[方法] 利用新获得的产甘油假丝酵母（Candida glycerinogenes）的相关抗逆转录因子CgSTB5、CgSEF1和CgCAS5，通过分子技术进行S.cerevisiae改造，考察其对酿酒酵母糠醛耐受性的影响，并尝试应用于未脱毒纤维素乙醇发酵。[结果] 单个表达CgSTB5和CgSEF1的酿酒酵母，通过菌株点板实验表明菌株的糠醛耐受性提高25%以上，并且摇瓶发酵结果显示糠醛降解性能明显提高，生长延滞期明显缩短，S.cerevisiae W303/p414-CgSTB5的未脱毒纤维素乙醇发酵生产效率提高12.5%左右。[结论] 转录因子CgSTB5和CgSEF1均能对提高酿酒酵母糠醛耐受性起到重要作用，并且有助于提高酿酒酵母菌株未脱毒纤维素乙醇发酵性能。

关键词:产甘油假丝酵母;酿酒酵母;糠醛耐受;转录因子;纤维素水解液

Abstract:

[Background] Cellulose is one of the main raw materials for biotransformation to solve energy problems. Furfural, existing in the cellulose hydrolysate, which seriously affects the growth inhibition of strains, must be detoxified before it can be applied in fermentation. Therefore, improving the strain tolerance of furfural is the key to solve the practical production application of cellulose hydrolysate. [Objective] Saccharomyces cerevisiae is a major industrial strain of cellulose hydrolysate fermentation, but it could not tolerant high furfural, and the strain with high furfural tolerance was obtained by molecular modification. [Methods] In this study, the furfural relevant transcription factors obtained from Candida glycerinogenes, CgSTB5, CgSEF1 and CgCAS5, were performed to modify S. cerevisiae to investigate their effects on furfural tolerance and apply to the ethanol fermentation of undetoxified cellulose. [Results] Expression of CgSTB5 or CgSEF1 could increase the furfural tolerance more than 25% in the spot plate experiment. The furfural degradation performance was significantly improved. The growth retardation period was shortened. The production efficiency of undetoxified cellulosic ethanol fermentation with S. cerevisiae W303/p414-CgSTB5 was increased by about 12.5%. [Conclusion] Both CgSTB5 and CgSEF1 could improve furfural tolerance in S. cerevisiae, which contribute to the improvement of the fermentation performance of undetoxified cellulosic ethanol in S. cerevisiae.

Key words:Candida glycerinogenes;Saccharomyces cerevisiae;furfural tolerance;transcription factors;cellulose hydrolysis solution