产己酸微生物筛选及其在浓香型白酒窖泥养护中的应用研究

Screening of caproic acid-producing microorganisms and their application in the pit mud maintenance of strong-flavor Baijiu

该研究采用富集培养及己酸定性和定量分析从浓香型白酒酒厂的窖泥中分离筛选高产己酸的己酸菌,通过形态学观察及分子生物学技术对其进行菌种鉴定,并将其应用于窖泥养护中,检测养护前后窖泥的理化指标及挥发性风味成分。结果表明,筛选并鉴定得到一株可稳定高产己酸的水原拉梅尔芽孢杆菌(Rummeliibacillus suwonensis)DFN-1,其传代3次后,己酸产量为8.15 g/L。通过菌株DFN-1养护窖泥后,窖泥的品质明显得到改善,其水分含量提高10.62%,腐殖质含量提高47.10%,总氮含量提高30.55%,耐热芽孢杆菌数提高9.98%,铵态氮含量提高35.94%,特征风味物质己酸和己酸乙酯相对含量分别提高至31.73%和0.43%。

In this study,caproic acid-producing bacteria with high yield caproic acid were isolated and screened from the pit mud of a strong-flavor(Nongxiangxing)Baijiu distillery by enrichment culture and qualitative and quantitative analysis of caproic acid,identified by morphological observation and molecular biology techniques,and applied in pit mud maintenance to test the physicochemical indexes and volatile flavor components of pit mud before and after maintenance.The results showed that a strain DFN-1 was screened and identified as Rummeliibacillus suwonensis,which was stable for high production of caproic acid.The caproic acid yield was 8.15 g/L after three passages.The quality of the pit mud was significantly improved after maintenance pit mud by the strain DFN-1,with the moisture contents increased by 10.62%,the humus contents increased by 47.6%,the total nitrogen contents increased by 30.55%,the thermophilic Bacillus count increased by 9.98%,the ammonium nitrogen content increased by 35.94%,and the relative contents of characteristic flavor substance caproic acid and ethyl caproate were increased to 31.73%and 0.43%,respectively.