保加利亚乳杆菌代谢含硫氨基酸关键酶基因差异分析及调控机制

项目名称： 保加利亚乳杆菌代谢含硫氨基酸关键酶基因差异分析及调控机制

项目编号： No.31301519

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： 刘丽波

作者单位： 东北农业大学

项目金额： 23万元

中文摘要： 乳酸菌水解酪蛋白形成含硫氨基酸是发酵乳的重要风味组成成分。调控乳酸菌生理代谢改善发酵乳制品的风味和质地不仅能够满足人们消费需求，更是提高我国发酵剂产业竞争力的重要手段。但目前对乳酸菌发酵中参与酪蛋白水解，含硫氨基酸代谢，并生成风味物质的相关酶基因差异和分子机理研究不十分清楚。本课题通过比较已知全基因组序列的保加利亚乳杆菌细胞壁蛋白酶、寡肽转移系统、细胞内肽酶和含硫氨基酸降解酶的生物信息学差异；通过生物信息学数据库、转录分析和相应的预测软件，重点地对含硫氨基酸降解路径相关酶进行分析比对、新功能注释，并修饰完善；研究结果结合直系同源鉴定和基因环境比较结果，分析并阐明含硫风味形成相关酶在保加利亚乳杆菌中的调控机制；并分析保加利亚乳杆菌和嗜热链球菌在共发酵过程中，含硫风味物质和胞外多糖合成相关基因关系，明晰两株菌在长期共进化过程中，含硫风味物质形成路径和其他代谢产物之间的关联。

中文关键词： 酪蛋白水解；含硫风味成分；关键酶；比较基因组学；调控机制

英文摘要： Proteolysis of lactic acid bacteria for casein is the most important biochemical pathway leading to formation of sulfur-containing flavour composition, and sulfur-containing amino acid is the most component of flavour composition in fermentation dairy products. Those regulated lactic acid bacteria on physiological metabolism would have been improved the flavor and quality of fermented dairy products, which can not only satisfy consumption demands from people, but also reinforce the competitive on industry of culture in our country However, to data, gene diversity and molecule mechanism of key enzymes related to sulfur-containing flavour composition is not still clear after lactic acid bacteria hydrolyze casein. In this project, comparative genomics is used to study bioformation diversity of cell-wall bound proteinase, peptides transport, peptidases and amino acids degradation enzymes from Lactobacilli bulgaricus and Streptococcus thermophilus, which genomes have been fully sequenced. Caseins proteolytic system, key enzymes of sulfur-containing amino acid degradation pathways is compared, annotations of these genes have been improved by information data library and transcriptional analysis and relevant putative software, the above results and compared results of orthology and gene context together are used to ana

英文关键词： Casein proteolysis；Sulfur-containing flavor compoisition；key enzymes；comparative genomics；regulation mechanisms