基于多尺度分析的凝结芽孢杆菌木糖代谢机理研究

项目名称： 基于多尺度分析的凝结芽孢杆菌木糖代谢机理研究

项目编号： No.31300487

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 农业科学

项目作者： 郑兆娟

作者单位： 南京林业大学

项目金额： 23万元

中文摘要： 木糖的高效利用是农林废弃物全面充分利用必须解决的关键问题之一。本申请中的凝结芽孢杆菌是近年来引起广泛关注的一类能代谢木糖产乳酸的菌株，相较于酵母菌等其他木糖代谢菌株，该菌株木糖代谢途径简单、理论转化率高、发酵过程易于调控。前期工作中发现凝结芽孢杆菌对木糖的利用效率低于其对葡萄糖的利用效率，鉴于此，本申请拟以自主筛选获得的凝结芽孢杆菌NL01为对象，利用适应性进化技术促进其木糖代谢进化，条件筛选获得木糖代谢产乳酸正向突变菌株；结合凝结芽孢杆菌基因组数据分析和代谢流分析构建其木糖代谢产乳酸网络；通过对比出发菌株和正向突变菌株木糖代谢产乳酸网络中的关键基因在基因序列、转录水平、翻译水平和酶活力水平的差异，对二者的木糖代谢途径进行多尺度全方位比较研究，探讨正向突变菌株木糖代谢效率提高机理，解析凝结芽孢杆菌木糖代谢产乳酸过程的本质，从而为进一步利用代谢工程手段构建木糖高效利用菌株提供理论依据。

中文关键词： 凝结芽孢杆菌；L-乳酸；木糖；基因组测序；转录组测序

英文摘要： The efficient utilization of xylose is one of the key prombles for comprehensive use of agricultural and forestry wastes. At present, the research of xylose is mainly focused on fermentation of ethanol by yeast strains, and less attention is paid on other microorganisms. Bacillus coagulans is a new kind of industrial microbe that can ferment xylose to lactic acid with a high theoretical yield and a simple fermentation process. Recently, we found that, for B. coagulans, the use efficiency of xylose was lower than that of glucose, which would limit its application potential in wood fiber resources. In this study, an independent selected strain, B. coagulans NL01, was used for adaptive evolution to improve its ferment ability on xylose and the positive mutation was obtained through conditioned screening. The network of xylose to lactic acid of B. coagulans was constructed based on the combination of genome data and metabolic flux analysis The original strain and the mutantion were compared on gene sequences, transcription, translation, and enzyme activities of the key genes in xylose metabolic network by multi-scale analysis. The mechanism on improved metabolic efficiency of positive mutation was discussed, which will lay a theoretical foundation on modifying of B. coagulans by metabolic engineering.

英文关键词： Bacillus coagulans；L-lactic acid；Xylose；Genome sequencing；RNA sequencing