应用PCR-DGGE技术分析酱香型白酒酒曲细菌多样性

利用PCR-DGGE技术研究酱香型白酒制曲过程中的细菌菌群结构及其消长规律，鉴定出不同样品的优势茵群。结果表明，酱香型大曲间的细茵组成存在明显差异，母曲与出仓曲的相似性系数仅为O．29。随着曲药的发酵，细菌多样性下降，优势茵群变化明显。其中，芽孢杆菌属（Bacillus）、明串珠菌属（Leuconostoc）、片球菌属（Pedio-cocuss）、魏斯氏菌属（Weissella）、棒状杆菌属（Corynebacterium）、高温放线茵属（Thermoactinomyces）和乳酸杆菌属（Lactobacillus）是母曲和翻仓曲的优势菌群，而出仓曲的主要类群为芽孢杆菌属（Bacillus）和乳酸杆菌属（Lactobacillus）。另外，还发现了在白酒曲药中不曾报道的种群和不能培养的细茵：Uncultured Propionibacteriaceae bacterium、Uncultured Weissellasp、Uncultured cyanobacterium，该技术克服了传统分离培养的缺点。

Application of PCR-DGGE to Analyze Bacterial Diversity in Maotai-flavor Daqu

The structure and the change rules of bacterial communities in Maotai-flavor Daqu during the fermentation were analyzed by PCR-DGGE.DNA sequencing was then proceeded to identify the dominant bacteria groups in different Daqu samples.The results showed that there was a significant difference in the composition of bacterial community in different Daqu samples and the similarity index was only 0.33 between Q1 and Q3.The bacterial diversity decreased and an obvious change occoured in dominant bacterial community as the fermentation proceeded.Bacillus,Leuconostoc,Pediococcus,Weissella,Corynebacterium,Thermoactinomyces and Lactobacillus were the predominant microflora in Q1 and Q2,but the dominant groups in Q3 merely included Bacillus and Lactobacillus.Besides,some uncultured bacteria and some bacterial communities never reported before such as uncultured Propionibacteriaceae bacterium,uncultured Weissellasp.and uncultured cyanobacteriu were found in our study.Therefore,PCR-DGGE could effectively overcome the shortcomings of traditional culture and isolation techniques.