Metabolic Engineering for Improving Ethanol Fermentation of Xylose by Yeasts and Bacteria
木糖发酵酒精代谢工程的研究进展

Efficient fermentation of xylose constitutes a major part of successful bioconversion of lignocellulosic biomass for ethanol and other important chemical production, but there is no natural microorganism suitable for efficiently transforming the renewable lignocellulosic materials. For the last two decades, many improvements have been made in the metabolic engineering of yeasts and bacteria including Zymomonas mobilis and Escherichia coli for the fermentation of xylose to selectively produce ethanol through introducing either xylose metabolic genes or ethanol production genes into the above hosts and a serial of recombinant strains have since been constructed. Although some of them have shown great promise for industrial exploitation, there still remain a lot of problems to be addressed. It seems necessary to make further improvements on the present strains on the basis of systematically learning more about the factors that control xylose metabolism. It also requires that the fermentation of recombinant strains be maximally optimized through biochemical engineering to achieve the bioconversion of lignocellulosic biomass into ethanol with high efficiency. The present review tries to outline some major efforts for developing microbial strains to efficiently ferment xylose to ethanol through metabolic engineering.