一株芝麻香型白酒高温大曲细菌Q2B1的鉴定及其产酶活性研究

Identification and enzyme activity of bacterium Q2B1 isolated from high-temperature Daqu of sesame-flavor Baijiu

大曲细菌关系到白酒酿造的品质,其中酶的含量与活性与白酒的风味紧密关联。以芝麻香型白酒高温大曲优势细菌代表菌株Q2B1为研究对象,利用分子生物学技术对其分类学地位进行研究,并通过全基因组研究技术对产酶相关功能基因与代谢通路进行研究。结果表明,菌株Q2B1被鉴定为贝莱斯芽孢杆菌(Bacillus velezensis)。利用传统的培养技术定性定量地检测其酶活力,发现菌株Q2B1可产淀粉酶和蛋白酶,活力分别为5.852 U/mL和26.770 U/mL;其产酶相关功能基因组长度为3475602 bp,包括蛋白酶编码基因以及淀粉酶编码基因,在基因水平上初步揭示了Q2B1菌株合成蛋白酶和淀粉酶的分子机理,为进一步合理开发白酒大曲微生物奠定理论基础,为提高白酒品质提供科学依据。

Bacteria in Daqu are related to the quality of Baijiu(Chinese liquor)brewing,in which the enzyme content and activity are closely related to the flavor of Baijiu.Using the representative strain Q2B1 of dominant bacteria isolated from high-temperature Daqu of the sesame-flavor Baijiu as the research object,the taxonomic status was studied by molecular biology techniques,and the functional genes related to enzyme production and metabolic pathways were studied by whole-genome research technique.The results showed that the strain Q2B1 was identified as Bacillus velezensis,and the enzyme activity was qualitatively and quantitatively determined by traditional culture technique.The strain Q2B1 could produce amylase and protease,and the enzyme activity was 5.852 U/ml and 26.770 U/ml,respectively.The genome length of functional genes related to enzyme production was 3475602 bp,including protease-encoding genes and amylase-encoding genes,and the molecular mechanism of protease and amylase synthesis by strain Q2B1 was preliminarily revealed,which laid a theoretical foundation for further rational developing microorganisms in Baijiu Daqu,and provided a scientific basis for improving the quality of Baijiu.