液固工艺山西陈醋发酵微生物群落组成、互作网络及溯源分析

The composition, interaction network, and source of microbial community in Shanxi mature vinegar produced by liquid-solid fermentation

摘要:

【背景】传统山西陈醋是在开放环境下由多菌种固态发酵酿制而成，解析酿造过程中微生物群落的组成、互作网络及来源对认识和调控食醋发酵过程都具有重要意义。【目的】揭示山西陈醋酿造微生物群落的组成、演替、互作网络及来源。【方法】基于高通量测序技术揭示山西陈醋酿造过程中微生物群落的组成、演替和多样性；采用SPSS数据统计软件计算物种间的斯皮尔曼相关系数并利用Gephi软件对微生物群落互作网络进行可视化分析；采用快速期望最大化微生物源跟踪(fast expectation-maximization microbial source tracking, FEAST)方法解析发酵微生物群落的来源。【结果】山西陈醋酿造过程中有6个优势细菌属和5个优势真菌属(平均相对丰度大于1%)；醋酸杆菌属(Acetobacter)、乳酸杆菌属(Lactobacillus)和复膜孢酵母属(Saccharomycopsis)的平均相对丰度较高，分别为20.76%、30.38%和46.24%；醋酸杆菌属(Acetobacter)的相对丰度在醋酸发酵阶段逐渐增加，而乳酸杆菌属(Lactobacillus)在此阶段的趋势则相反。微生物群落互作网络结果显示魏斯氏菌属(Weissella)、乳球菌属(Lactococcus)、季也蒙酵母属(Meyerozyma)、Loigolactobacillus、Schleiferilactobacillus和地杆菌属(Geobacter)具有较高的连接度(连接度≥7)；此外，醋酸杆菌属(Acetobacter)与魏斯氏菌属(Weissella)、Schleiferilactobacillus、Loigolactobacillus、乳球菌属(Lactococcus)、季也蒙酵母属(Meyerozyma)具有显著的拮抗作用。来源追溯结果显示糖化发酵第2天样品中有1.02%的细菌群落和77.04%的真菌群落来源于大曲；在醋酸发酵第1天样品中有0.93%的细菌群落和52.82%的真菌群落来源于火醅。【结论】为了解山西陈醋酿造过程中微生物群落的组成、演替、互作网络和解释酿造微生物来源提供了重要的理论数据。

Abstract:

[Background] Traditional Shanxi mature vinegar is produced by solid-state fermentation with multiple strains in an open environment. Revealing the composition, interaction network, and source of microbial community facilitates the understanding and regulation of the vinegar fermentation process. [Objective] To reveal the composition, succession, interaction network, and source of microbial community in Shanxi mature vinegar during the fermentation process. [Methods] High-throughput DNA sequencing was performed to reveal the composition, succession, and diversity of the microbial community. SPSS was employed to calculate the Spearman correlation coefficient between species and Gephi was used for the visual analysis of the microbial interaction network. Fast expectation-maximization microbial source tracking (FEAST) was employed to analyze the origin of the microorganisms. [Results] Six bacterial genera and five fungal genera (average relative abundance greater than 1%) were dominant in the fermentation process of Shanxi mature vinegar. The average relative abundance of Acetobacter, Lactobacillus, and Saccharomycopsis were 20.76%, 30.38%, and 46.24%, respectively. The relative abundance of Acetobacter increased gradually during acetic acid fermentation, while the opposite trend was observed for Lactobacillus. The microbial community interaction network showed that Weissella, Lactococcus, Meyerozyma, Loigolactobacillus, Schleiferilactobacillus, and Geobacter had high connectivity (≥7). In addition, Acetobacter demonstrated significant antagonism with Weissella, Schleiferilactobacillus, Loigolactobacillus, Lactococcus, and Meyerozyma. The results of source tracking showed that 1.02% of bacteria and 77.04% of fungi were derived from Daqu on the second day of saccharification. On the first day of acetic acid fermentation, 0.93% of bacteria and 52.82% of fungi were derived from fermented grains. [Conclusion] This study provided important theoretical data for understanding the composition, succession, and interaction network of microbial community and tracking the source of microorganisms during the fermentation process of Shanxi mature vinegar.