酱香白酒第七轮次堆积发酵过程中细菌群落的动态变化

Dynamic Change of Bacterial Community During Seventh Round Stacking Fermentation of Maotai-flavor Baijiu

高温堆积发酵又称为“二次制曲”,是酱香型白酒生产的核心工艺之一。为进一步解析堆积过程中复杂的微生物体系及菌群结构的动态变化,本研究基于Illumina MiSeq技术对贵州省仁怀市某知名酒厂第七轮次堆积发酵阶段的细菌群落结构及动态变化进行分析。结果表明:整个堆积阶段的优势细菌门为厚壁菌门(Firmicutes)和变形菌门(Proteobacteria)。优势细菌属中,克罗彭斯特菌属(Kroppenstedtia)和枝芽孢杆菌属(Virgibacillus)在整个堆积过程中所占丰度比不断减小;假单胞菌属(Pseudomonas)、链状球菌属(Streptococcus)、高温放线菌属(Thermoactinomyces)、糖多孢菌属(Saccharopolyspora)和红球菌属(Rhodococcus)在堆积过程中相对丰度呈现先上升后下降的趋势;大洋芽孢杆菌属(Oceanobacillus)和芽孢杆菌属(Bacillus)在堆积过程中相对丰度先上升后趋于稳定。研究发现堆积前期细菌群落结构变化较大,堆积中后期细菌群落结构相似。环境因子关联分析表明堆积温度对细菌菌群结构的影响最大,醅料淀粉含量与未分类的芽孢杆菌属和克罗彭斯特菌属等主要菌属的相对丰度呈正相关。本研究结果有助于解析酱香型白酒第七轮次堆积发酵阶段的核心细菌群落动态变化和环境因子的关联性,为实现酱香型白酒的轮次精准调控提供理论依据。

High temperature stacking fermentation is also called"secondary koji making",which is one of the core technologies in Maotai-flavor Baijiu production.In order to further analyse the complex microbial system in the fermentation process,the bacterial diversity and dynamic changes in the seventh round of stacking fermentation was researched by Illumina MiSeq technology.The results showed that the dominant bacteria in different periods were Firmicutes and Proteobacteria at the phylum level.At the genus level,the abundance ratio of Kroppenstedtia and Virgibacillus decreased continuously during the whole fermentation process.The relative abundance of Pseudomonas,Streptococcus,Thermoactinomyces,Saccharopolyspora and Rhodococcus increased at first and then decreased during the fermentation process.The relative abundance of Oceanobacillus and Bacillus increased at first and then tended to be stable during fermentation process.The bacterial community changed greatly in the early stage of fermentation and tended to be stable in the late stage of fermentation.Among environmental factors,temperature had the greatest effect on bacterial community structure,and starch content was positively correlated with the main bacteria genera including unclassified Bacillus,Kroppenstedtia and Virgibacillus.This study is not only helpful to analyze the relationship between the dynamic change of core bacterial community and environmental factors in the seventh round fermentation stage of Maotai-flavor Baijiu,but also provide a theoretical basis for the accurate control of Maotai-flavor Baijiu rounds.