泸型酒酒醅与窖泥中乳酸菌群落结构差异

Differences in the lactic acid bacterial community structure between jiupei and pit mud during the fermentation of Luzhou-flavour baijiu

乳酸菌对泸型酒风味品质的发酵形成具有重要作用.为促进对酒醅和窖泥中乳酸菌群落物种组成、发酵演替规律以及表型差异的深入认识,采用分子生态学技术,在种水平上对比和揭示同一窖池酒醅和窖泥中乳酸菌群落的结构差异和演替规律,并运用BugBase预测酒醅和窖泥乳酸菌群落主要表型的差异.结果显示,窖池中共检出6科16属乳酸菌.酒醅发酵过程中乳酸菌平均丰度为65.21%±29.47%,而窖泥中乳酸菌仅占细菌总量的4.06%±4.24%.0-3 d酒醅中优势乳酸菌是乳杆菌属(Lactobacillus,占乳酸菌丰度44.01%)、魏氏菌属(Weissella,27.33%),其后乳杆菌属丰度维持在91.06%以上,窖泥中优势乳酸菌为乳杆菌属(95.67%±9.17%).OTU0和OTU3是窖池中乳杆菌属的优势物种,其丰度占乳酸菌总量的76.08%±29.21%.酒醅与窖泥乳酸菌需氧类型不同,发酵初期(0-5 d)的酒醅中好氧乳酸菌相对丰度显著高于后期酒醅和窖泥样品(P<0.01),窖泥中兼性厌氧乳酸菌的丰度高于酒醅样品.综上所述,酒醅和窖泥中乳酸菌群落存在时空异质性,可能影响酒醅和窖泥对泸型酒风味的贡献.(图4参34)

The lactic acid bacteria(LAB)inhabiting cellars can play a key role in the fermentation process of the Luzhou-flavor baijiu.For a comprehensive understanding of LAB communities in the fermentation ecosystem on a species level,this work aimed to study the structure,succession,and phenotype of LAB communities between jiupei and pit mud using high-throughput sequencing and BugBase.Results showed that the relative abundance of LAB during fermentation in jiupei and pit mud were 65.21%±29.47%and 4.06%±4.24%,respectively.The taxa of LAB detected in the cellar included 155 genera and 6 families,in which Lactobacillus and Weissella dominated in jiupei in the first 3 days and accounted for 44.01%and 27.33%of the LAB abundance,respectively.In addition,the abundance of Lactobacillus was above 91.06%in jiupei and 95.67%±9.17%in the pit mud.The optical transport network(OTU0)and OTU3,affiliated with Lactobacilli,were the dominant LAB species in the cellar,with the total abundance of 76.08%±29.21%.During the early stages(0-5 days)of jiupei,the abundance of aerobic LAB was significantly higher than that of later jiupei and pit mud samples(P<0.01),while the abundance of facultative anaerobic LAB in the pit mud was higher relative to the jiupei samples.In summary,spatial and temporal heterogeneity is present in the LAB community in the baijiu fermentation cellar due to the differences in environmental factors between jiupei and pit mud,where both could contribute to the Luzhou-flavor baijiu.