酿酒酵母Mbp1缺陷型菌株的构建及其乙醇发酵特性

Construction of Saccharomyces cerevisiae ΔMbp1 and its alcohol fermentation characteristics

摘要:

【目的】研究酿酒酵母(Saccharomyces cerevisiae)工业菌株Mbp1基因的功能，探讨Mbp1基因对酿酒酵母乙醇发酵性能的影响。【方法】以酿酒酵母MF1015为出发菌株，用PCR方法构建Mbp1基因敲除组件Loxp-KanMX-Loxp，将敲除组件转化两种配型的酿酒酵母单倍体，通过单倍体复倍获得敲除Mbp1基因的二倍体突变菌株，研究突变菌株形态变化及乙醇发酵特性。【结果】敲除Mbp1基因后突变菌株生长曲线无显著变化，出芽率降低，细胞体积增大19.2%，对饥饿更敏感，较早出现假菌丝。甘蔗糖蜜在静置条件下发酵，突变菌株的乙醇产量明显低于野生型；在130 r/min的条件下发酵，突变菌株和野生型发酵液中的乙醇产量基本相同。【结论】Mbp1基因缺失使酿酒酵母的乙醇发酵能力下降并影响细胞的形态分化。

Abstract:

[Objective] To study the function of Mbp1 gene, including the effects of Mbp1 gene mutation on ethanol fermentation of Saccharomyces cerevisiae. [Methods] The Loxp-KanMX-Loxp was constructed and transformed into haploid Saccharomyces cerevisiae MATa and MATα. After haploid mating test, the diploid mutant was selected. Ethanol fermentation and physiological studies of the mutant were performed and compared with those of the wild type strain. [Results] The growth rate of the mutant was similar to that of the wild strain; the budding rate of mutant strain is lower than that of the parent strain during the fermentation before 48 h; the mutant is approximately 19.2% bigger than the parent strain in cell volume and was more sensitive to nutrient starvation; in addition, pseudomycelium was also observed in the mutant. The ethanol production and sugar utilization ability of the mutant is slightly lower than that of the parent strain. The ethanol production level of mutant strain is lower than that of the wild strain in static culture, while there is no different between the mutant strain and the wild strain in agitated culture at 130 r/min. [Conclusion] Mbp1 is involved in fermentability and morphogenesis of Saccharomyces cerevisia.