浓香型大曲中1株高发酵力芽孢杆菌的筛选和鉴定

Screening & Identification of a Bacillus Strain with High Fermenting Power in Nongxiang Daqu

通过研究浓香型大曲不同制曲阶段的菌种资源,以丰富白酒酿造的微生物资源库。采用平板初筛、固态发酵复筛,从不同制曲阶段筛选高发酵力芽孢杆菌,并进行16S rDNA鉴定。对优选菌株固态发酵产物采用HS-SPME-GC-MS方法初步探寻芽孢杆菌和风味物质之间的相关性。结果表明,编号X13菌株的发酵力为0.49 g/0.5 g·72 h,达到了传统大曲发酵力的优良等级,并鉴定其为贝莱斯芽孢杆菌(Bacillus velezensis);X13菌株固态发酵能产生17种挥发性风味物质,包括吡嗪类物质、酚类物质、醇类物质、醛类物质和酯类物质等,可初步确定为大曲功能菌株。

The exploration on bacteria species resource in different Daqu-making stages could enrich liquor-making microbes resource bank. In the experiment, plate preliminary screening and solid fermentation secondary screening were adopted to screen Bacillus strains with high fermenting power in different Daqu-making stage. Afterwards, 16 S rDNA identification was performed. And the correlativity between Bacillus stains and flavoring substances was investigated through HS-SPME-GC-MS analysis of the fermenting product of the screened strains. The results showed that, the fermenting power of X13 strain was as high as 0.49 g/0.5 g·72 h, which was in accord with quality level of traditional Daqu fermenting power, and it was identified as Bacillus velezensis. The solid-state fermentation of X13 strain could produce 17 kinds of volatile flavoring substances including pyrazines, phenolics, alcohols, aldehydes and esters etc. X13 strain was a Daqu functional strain.