沉香型酒醅中产香芽孢杆菌的分离鉴定及代谢产物分析

从沉香型酒醅中分离产香芽孢杆菌并进行发酵风味分析。通过平板分离得到4株产香较好的芽孢杆菌，并进行16S rDNA序列分析和构建系统发育树，4株菌分别为阿式芽孢杆菌（Bacillus aryabhattai）、地衣芽孢杆菌（Bacillus licheniform）、枯草芽孢杆菌（Bacillus subtilis）、解淀粉芽孢杆菌（Bacillus amyloliquefaciens）。其中地衣芽孢杆菌产蛋白酶和淀粉酶能力均为最强且最适生长温度为50 ℃。以玉米粉为底物进行单菌液态发酵，采用固相萃取和气相色谱-质谱法(SPME-GC-MS)分析发酵液中的风味物质，一共检测到24种风味物质，其优势产物主要为3-羟基-2-丁酮、2,3-丁二醇和一些酸类等风味物质。由此而见，阿式芽孢杆菌、地衣芽孢杆菌、枯草芽孢杆菌、解淀粉芽孢杆菌这4类菌对沉香型白酒风味的形成均具有重要作用。

Isolation,identification and metabolite analysis of aroma-producing Bacillus from fermented grains of Chen-xiang flavor Baijiu

The aroma-producing Bacillus were isolated from fermented grains of Chen-xiang flavor Baijiu and their major metabolites were analyzed. Four strains of better aroma-producing Bacillus were isolated by the plate dilution method. By 16S rDNA sequences analysis and phylogenetic tree establishment, the 4 strains were identified as Bacillus aryabhattai, Bacillus licheniformi, Bacillus subtilis and Bacillus amyloliquefaciens, respectively. Among them, B. licheniformi was the strongest in producing protease and amylase, and the optimum growth temperature was 50 ℃. The liquid fermentation of single bacterium was carried out with corn flour as the substrate. The flavor compounds in the fermented broth were analyzed by SPME-GC-MS, and a total of 24 flavor compounds were detected. The dominant products were mainly 3-hydroxy-2-butanone, 2,3-butanediol, some acids and other flavor compounds. Thus, B. aryabhattai, B. licheniformis, B. subtilis and B. amyloliquefaciens played an important role in the flavor formation of Chen-xiang flavor Baijiu.