木糖发酵重组酿酒酵母研究进展_英文_

573 863计划（2009AA05Z436）和中国科学院广州能源研究所所长创新基金人才引进项目(o807rd)资助 收稿日期: 2010-02-25; 修回日期: 2010-04-19; 网络出版日期: 2011-04-27 网络出版地址: http://www.cnki.net/kcms/detail/11.2442.N.20110427.1216.006.html

北京大学学报(自然科学版), 第47卷, 第3期, 2011年5月 Acta Scientiarum Naturalium Universitatis Pekinensis, Vol. 47, No. 3 (May 2011)

Research Advances on Xylose-Fermenting Recombinant Saccharomyces cerevisiae

ZHU Shunni1, ZHANG Mingting1,2, ZHOU Weizheng1, ZHUANG Xinshu1, XU Huijuan1, QI Wei1, YUAN Zhenhong1,†

1. Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640; 2. College of Life Science, Capital Normal University, Beijing 100048; † Corresponding author, E-mail: yuanzh@ms.giec.ac.cn

Abstract Bioconversion of lignocellulosic raw materials into ethanol has aroused extensive attention in recent years. High ethanol yields are dependent on co-fermentation of hexose and pentose sugars present in lignocellulosic hydrolysates. However the traditional ethanologenic yeast Saccharomyces cerevisiae has been found to be unable to ferment xylose and also unable to utilize this pentose sugar for growth. Hence attempts have been made to construct various recombinant yeasts to improve the ability of xylose fermentation. In this article, progress in development of xylose-fermenting recombinant S. cerevisiae strains is reviewed, including naturally occurring xylose-fermenting microorganisms, xylose metabolic pathway, metabolic engineering of S. cerevisiae, protoplast fusion and genome shuffling. Problems existing in current researches and prospects are also discussed. Key words xylose fermentation; Saccharomyces cerevisiae; metabolic engineering; protoplast fusion; genome shuffling

木糖发酵重组酿酒酵母研究进展 朱顺妮1 张明婷1,2 周卫征1 庄新姝1 徐惠娟1 亓伟1 袁振宏1,† 1. 中国科学院广州能源研究所, 广州510640; 2. 首都师范大学生命科学学院, 北京100048; † 通信作者, E-mail: yuanzh@ms.giec.ac.cn

摘要 近年来针对木质纤维素类原料生物转化乙醇的研究引起了广泛关注。乙醇的高产依赖于木质纤维素水解液中六碳糖和五碳糖的共同发酵。但是, 传统产乙醇酵母酿酒酵母Saccharomyces cerevisiae既不能发酵木糖, 也不能利用该五碳糖生长。因此, 研究人员尝试各种方法构建重组酵母菌以提高木糖发酵能力。作者综述了木糖发酵重组酿酒酵母菌的研究进展, 包括天然木糖发酵微生物、木糖代谢途径、S. cerevisiae的代谢工程、原生质体融合以及基因组改组技术, 同时也对目前研究存在的问题及研究前景进行了讨论。 关键词 木糖发酵; 酿酒酵母; 代谢工程; 原生质体融合; 基因组改组 中图分类号 Q939

With the inevitable depletion of the world’s energy supply and the prospect of global warming, there has been an increasing worldwide interest in alternative fuels such as bioethanol[1]. Presently, ethanol is exclusively produced from starch or sucrose fraction of agricultural crops such as corn, sugar beet and grain, which results in an undesirable increase in the price of grain and food while decreasing the fertility of the agricultural fields. To expand the feedstock range and improve productivity for 北京大学学报(自然科学版) 第47卷 574 large-scale ethanol production, it is of vital importance to enable efficient ethanol production from lignocellulose. Lignocellulosic feedstocks are much more abundant than food crops, have fewer competing uses, and can be harvested with considerably less interference to the food economy and less strain on environmental resources, thus having great potential for ethanol production [2]. Ethanol production from lignocellulosic feedstocks poses a number of challenges compared to that from conventional starch- or sucrose- based feedstocks. One important technical factor restricting conversion of lignocellulose to ethanol is xylose fermentation[3]. Upon hydrolysis, lignocellulose yields a mixture of monomeric hexoses (glucose, mannose and galactose) and pentoses (xylose and arabinose). Among these, glucose is normally the most abundant, followed by xylose or mannose, as well as other sugars present in much lower concentrations[4]. Hinman et al.[5] analyzed that practicable xylose fermentation with acceptable yields and ethanol concentrations could lower the overall cost of ethanol from wood by 25%. Unfortunately, while many microorganisms can convert hexoses efficiently into ethanol, the utilization and bioconversion of xylose remain relatively inefficient. Since the conversion of xylose to ethanol was addressed in the early 1980s [6], extensive researches on xylose metabolism have been developed. As well, many efforts have been made through genetic engineering of yeasts for the fermentation of xylose to ethanol. This review focuses on the current status of these efforts and prospects of bioconversion of xylose to ethanol by Saccharomyces cerevisiae.

1 Metabolism of Xylose 1.1 Microorganisms for xylose fermenta- tion Species of bacteria, yeasts, and filamentous fungi are capable of fermenting xylose to ethanol. Each group of microorganisms has its advantages and disadvantages considering the lignocellulosic context and modern engineering strategies [7]. However, yeasts