紫外诱变驯化提高酿酒酵母木糖发酵的抑制物耐受性

摘要

利用驯化和紫外处理结合驯化的手段对一株木糖发酵工业菌株的抑制物耐受性进行提升.在反复批次培养过程中不断提高含9种抑制物的混合抑制物浓度,使细胞的生长和发酵逐渐适应高浓度抑制物环境,分离突变菌株并进行评价.紫外处理结合驯化比直接驯化能更有效的提升细胞对高浓度抑制物的耐受能力;通过突变菌株分离和筛选,获得3株抑制物耐受能力高于出发菌株的突变菌株,它们在抑制物浓度100%MI(甲酸1 g/L,乙酸3.5 g/L,乙酰丙酸1.5 g/L,糠醛1.5 g/L,5-羟甲基糠醛1.5 g/L,丁香醛0.1 g/L,香草醛0.1 g/L,松柏醛0.025 g/L,肉桂酸0.025 g/L)条件下的木糖消耗率比出发菌株高出11.3%-23.2%.紫外诱变处理结合驯化过程可以有效提高酿酒酵母对混合抑制物的耐受性.%The inhibitor tolerance of a xylose-fermenting industrial Saccharomyces cerevisiae strain was improved through direct acclimation or ultraviolet mutation combined with acclimation. During the repeated batch incubations,the concentration of the mixed inhibitors, containing nine kinds of typical inhibitors,was gradually increased to make cells adapt to the high inhibitor concentration. UV mutation combined with acclimation improved the tolerance of cells to inhibitors with high concentrations more effectively than direct acclimation. By the isolation and screening of mutation strains,three mutation strains with better inhibitor tolerance than the original strain were obtained. They showed 11.3%-23.2% higher xylose consumption ratios than the original strain when fermenting xylose under the inhibitory condition of 100% MI(formic acid 1 g/L,acetic acid 3.5 g/L,levulic acid 1.5 g/L,furfural 1.5 g/L,5-hydroxymethylfurfural(5-HMF)1.5 g/L, syringaldehyde 0.1 g/L,vanillin 0.1 g/L,coniferaldehyde 0.025 g/L,cinnamic acid 0.025 g/L). UV mutation combined with acclimation improved the tolerance of S. cerevisiae strain to mixed inhibitors.