青稞酒曲微生物多样性分析及米根霉制曲条件优化

Investigation of the microbial diversity in Highland barley Qu and optimization of the Koji-making condition with Rhizopus oryzae

采用高通量测序和分离培养相结合的方法对青稞酒曲进行微生物多样性分析,分离培养酒曲中的优势微生物,制作青稞酒纯种曲。结果表明,酒曲中真菌主要有根霉属、曲霉属、线虫草属和酵母属,其中米根霉是酒曲中真菌的优势菌株,同时也是主要糖化菌;细菌主要有库克菌属、球菌属、芽孢杆菌属、微球菌属等。随后,在利用米根霉制作纯种曲时发现,培养温度30℃、麸皮青稞粉配比2∶1、料水比40%、培养时间72 h、种曲接种量3.5%时糖化酶活力为1 246.9 U/g,液化酶活力为61.4 U/g,比原曲酶活力分别提高了9.2、2.4倍。

In this paper,the high-throughput sequencing and cultured methods were combined for analyzing the diversity of microorganism in Highland barley Qu and determining the dominant strain. The results suggested that the predominant fungi were Rhizopus,Aspergillus,Ophiocordyceps and Saccharomyces,whereas Rhizopus oryzae was the major fungus and the main microorganism for saccharification. Moreover,the predominant bacteria were Kocuria,Macrococcus,Bacillus and Micrococcus. In addition,the results of the optimal Koji-making condition with Rhizopus oryzae showed that the enzymes activity of saccharifying enzyme and liquifying enzyme were up to 1 246. 9 U/g and 61. 4 U/g when it was cultured at 30 ℃ for 72 h with raw material ratio of 2∶ 1,liquid ratio of 40%,and inoculum of 3. 5%,which were 9. 2 times and 2. 4 times higher than that of originally Qu,respectively.