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

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