清香型大曲中产香细菌的分离筛选及鉴定

为提升麸曲清香型白酒风味品质，该研究采用稀释平板涂布培养法从清香型白酒大曲中分离纯化细菌，采用感官嗅闻法从中筛选出具有产香气功能的细菌菌株，将其应用于麸曲白酒酿造，并通过形态观察及分子生物学技术对其进行菌种鉴定。结果表明，分离筛选得到2株具有香气功能的细菌，编号分别为HXX7和HXX12，其发酵液中挥发性香气成分丰富，均含有酯类、醛酮类、酚类、杂环类化合物等，具有较强产香能力。将菌株HXX7和HXX12分别应用于麸曲清香型白酒生产，其中，菌株HXX7发酵酒样中丁酸乙酯（41.91 mg/L）、4-乙基愈创木酚（148.70 mg/L）、3-羟基-2-丁酮（312.68 mg/L）、苯乙醛（79.27 mg/L）、β-苯乙醇（128.38 mg/L）含量升高。结果表明，菌株HXX7可增加原酒香气，改善原酒风味，从而提升白酒品质。菌株HXX7被鉴定为地衣芽孢杆菌（Bacillus licheniformis）。

Isolation,screening and identification of aroma-producing bacteria in light-flavor Baijiu Daqu

In order to improve the flavor quality of Fuqu light-flavor Baijiu (Chinese liquor), the bacteria were isolated and purified from light-flavor Baijiu Daqu by dilution plate coating culture method. The bacterial strains with aroma-producing function were screened by sensory smelling method, and they were applied to Fuqu Baijiu brewing and identified by morphological observation and molecular biology techniques. The results showed that two strains of bacteria with aroma function were isolated and screened, and numbered as HXX7 and HXX12, respectively. The volatile aroma components in the fermentation broth were rich, including esters, aldehydes and ketones, phenols, heterocyclic compounds and so on, with stronger aroma production ability. The strains HXX7 and HXX12 were applied to the production of Fuqu light-flavor Baijiu respectively. Among them, the contents of ethyl butyrate (41.91 mg/L), 4-ethyl guaiacol (148.70 mg/L), 3-hydroxy-2-butanone (312.68 mg/L), phenylacetaldehyde (79.27 mg/L) and β-phenylethanol (128.38 mg/L) in Baijiu samples fermented by strain HXX7 increased. The results showed that the strain HXX7 could increase the aroma of original liquor, improve flavor of original liquor, thus improve Baijiu quality. The strain HXX7 was identified as Bacillus licheniformis.