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利用纤维素原料生产乙醇一直是国内外研究的热点,但纤维素预处理过程产生的弱酸、酚类和糠醛等抑制物对酿酒酵母细胞生长和乙醇发酵具有抑制作用,因此,提高酿酒酵母细胞的环境胁迫耐受性是提高纤维素乙醇发酵效率的重要手段之一.对芳香族氨基酸代谢途径中分支酸歧化酶基因ARO7的过表达对酿酒酵母在胁迫条件下细胞生长和乙醇发酵性能的影响进行研究.结果显示,过表达ARO7的重组菌株在含有5.0 g/L乙酸的平板中生长优于对照菌株;在含有5.0 g/L乙酸的发酵培养基中进行乙醇发酵,过表达ARO7的重组菌株的发酵效率高于对照菌株,在菊芋秸秆水解液中ARO7过表达重组酵母菌株乙醇得率由对照的0.44 g/g提高到0.47 g/g葡萄糖,乙醇生产强度提高了22.38%.以上表明,ARO7的过表达可提高酿酒酵母在抑制物存在条件下纤维素乙醇的发酵效率.
The production of ethanol from cellulose raw materials has been a hot research field at home and abroad. However, inhibitors of weak acids, phenols and furfural produced by cellulose pretreatment have inhibitory effects on the growth of Saccharomyces cerevisiae and ethanol fermentation. Therefore, Environmental stress tolerance is one of the most important ways to improve the efficiency of cellulosic ethanol fermentation.Overexpression of the chorisperoxide dismutase gene ARO7 in the aromatic amino acid metabolic pathway affects the growth of S. cerevisiae under the stress conditions and the effect of ethanol fermentation The results showed that the recombinant strain overexpressing ARO7 grew better than the control strain in a plate containing 5.0 g / L acetic acid, ethanol fermentation in a fermentation medium containing 5.0 g / L acetic acid, and that of the recombinant strain overexpressing ARO7 The fermentation efficiency of ARO7 overexpressing yeast strain was increased from 0.44 g / g to 0.47 g / g glucose in the Jerusalem artichoke straw hydrolyzate, and the ethanol production intensity increased by 22.38% Overexpression can improve the fermentation efficiency of cellulosic ethanol in Saccharomyces cerevisiae in the presence of inhibitors.