中文摘要：

乙偶姻是传统发酵食醋重要的风味物质,也是食醋中活性物质川芎嗪形成的重要前体.采用克隆文库分析方法对镇江香醋醋醅中乙偶姻合成途径的两个关键酶（乙酰乳酸合成酶ALS,乙酰乳酸脱羧酶ALDC）的基因多样性进行分析.结果表明,ALS基因克隆文库中相对丰度最大为Lactobacillus buchneri（65.7%）,其次为Acetobacter pasteurianus（21.3%）、L.reuteri（10.2%）、L.casei（1.9%）、L.brevis（0.9%）;而ALDC基因克隆文库中A.pasteurianus（91.2%）占绝对优势,且呈现丰富的种内基因多样性,另外还有少量L.fermentum（8.8%）.因此,Acetobacter和Lactobacillus可能是醋醅微生物群落中利用丙酮酸合成乙偶姻的主要参与者;本研究可为解析多菌种醋酸发酵过程中乙偶姻微生物合成机理奠定研究基础,同时为其他微生物群落功能的研究提供参考.

英文摘要：

This research aimed to study the gene diversity of two key enzymes in the acetoin pathway in the vinegar Pei and to lay foundation for the functional microbial community reconstruction. Degenerate primers were designed, validated and used for the amplification of gene coding for acetolactate synthase（ALS） and acetolactate decarboxylase（ALDC） in vinegar Pei. Then two gene clone libraries were established respectively and analyzed by rarefaction curve, cluster analysis and phylogenetic analysis. Two pairs of degenerate primers were validated to be of high specificity and used for the clone libraries construction. Sequences in ALS clone library were clustered to 6 Operational Taxonomic Units（OTUs） and the most abundant species was proved to be Lactobacillus buchneri（65.74%）. Sequences in ALDC clone library were clustered to 16 OTUs and the most abundant species was Acetobacter pasteurianus（91.23%）. The research found that Lactobacillus and Acetobacter might be the main functional genera for the production of ALS and ALDC in the vinegar Pei.