对重组大肠杆菌KO11利用单糖转化乙醇的能力进行了研究与优化,结果表明,KO11对己糖中的半乳糖、甘露糖、葡萄糖和戊糖中的岩藻糖、木糖均有较高的乙醇转化率。通过对KO11利用葡萄糖与木糖发酵的考察发现,以4%(v/v)接种量接种于含葡萄糖20 g/L的LB培养基中,KO11在pH 5.5、37℃、150 r/min振荡培养4 h后再静置发酵20 h能够达到乙醇转化率94.81%;将其接种于含同样浓度木糖的LB培养基在相同的pH、发酵温度与振荡速度下振荡12 h后再静置发酵15 h达到乙醇转化率94.15%。另外,KO11具有较高糖耐受性,发酵葡萄糖与木糖混合糖时优先利用葡萄糖,并且在43℃时仍表现出较高的乙醇转化率,为利用该菌种进行纤维质水解液发酵提供了参考依据。

The ability of converting monosaccharide into ethanol by recombinant Escherichia coli KO11 was studied and optimized. Ethanol could be effectively produced by KO11 which fermented a wide range of monosaccharides including hexose and pentose,whereas yeast utilized hexose only. Under the optimum conditions of pH 5. 5,37 ℃and 150 r / min,the maximum ethanol yield was obtained up to 94. 81%( 20 g / L glucose) after KO11 was cultured in LB medium by agitating for 4 h and standing for 20 h,and up to 94. 15%( 20 g / L xylose) after culturing by agitating for 12 h and standing for 15 h. In addition,KO11 kept good performance at higher temperature( 43 ℃),which provides advantage for the simultaneous saccharification and fermentation processing.