陶融型大曲中产香微生物的筛选及鉴定

本研究从陶融型大曲微生物资源中筛选产香功能性微生物,研究其与大曲香味物质之间的联系,并对产香功能菌株进行分子生物学鉴定。采用传统微生物分离法从不同发酵阶段的陶融型大曲中分离纯化获得细菌37株,酵母22株。以小麦固体培养基为底物对各菌株进行单菌产香实验,经闻香评定,菌株YSY04发酵后能产生浓郁的香味。采用顶空固相微萃取-气相色谱-质谱联用技术对这该菌株的发酵产物进行挥发性成分检测,发现该菌株的发酵产物中香味物质种类丰富,其中吡嗪类物质、苯乙醇、愈创木酚、2,3-丁二醇和萜烯类等香味物质为陶融型大曲的重要香味成分。因此,可初步认定菌株YSY04为陶融型大曲的产香功能菌。经形态学观察和分子生物学鉴定,菌株YSY04为异常威克汉姆酵母(Wickerhamomycesanomalus)。

Screening and Identification of Aroma-producing Microorganisms in Pottery-flavor Daqu

Aroma-producing microorganisms were screened from the microbial resources of pottery-flavored daqu. The relationship between aroma-producing microorganisms and flavoring substances in Luzhou-flavored daqu was also investigated. Functional aroma-producing microorganisms were identified using various molecular biology techniques. Multiple strains of bacteria (37) and yeast (22) were isolated and purified from the various fermentation stages of pottery-flavored daqu by traditional microbial separation. Each strain was separately cultured in wheat solid growth medium. The sensory evaluation (smell test) showed that the individual strain YSY04 could produce strong flavors after fermentation. The volatile components present in the fermentation products of the strains were identified by headspace solid-phase micro extraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). This analysis identified a number of flavor substances in the fermentation products of the strain. Among them, pyrazine, phenylethanol, guaiacol, 2,3-butanediol, and terpenes were identified as important flavor substances present in pottery-flavored daqu. Therefore, the strain was primarily identified as the functional aroma-producing microorganism present in pottery-flavored daqu. Morphological observation and molecular biology identification analysis confirmed that the YSY04 strain belonged to the species Wickerhamomyces anomalus.