青稞酒发酵过程中的风味功能微生物及其风味代谢特征解析

Flavor-related microbiota and their flavor metabolism during highland barley Baijiu fermentation

摘要:

【背景】青稞酒是一个多菌种固态发酵的产物，解析发酵过程中重要的功能微生物及其代谢特征对调控青稞酒发酵具有重要作用。【目的】揭示青稞酒发酵过程中的风味功能微生物并解析其风味代谢特征。【方法】基于高通量测序技术揭示青稞酒发酵过程中的微生物群落多样性和组成；采用顶空固相微萃取结合气相色谱-质谱技术跟踪酒醅的风味信息；通过微生物属与风味物质的关联分析揭示青稞酒发酵过程中风味功能微生物菌群，并采用蒙特卡洛检验分析进一步揭示发酵过程理化因子对风味功能微生物菌群的影响；于实验室环境下重构6株微生物发酵体系，以揭示其风味代谢特征。【结果】青稞酒发酵过程中9个真菌属和8个细菌属(相对丰度>1%)占据优势，其中Aspergillus、Komagataella、Lactobacillus、Pichia、Saccharomyces和Weissella是青稞酒发酵过程主要风味功能微生物；发酵过程中还原糖(r2=0.946 9，P=0.013 2)和酸度(r2=0.847 6，P=0.048 6)是驱动风味功能微生物菌群演替的关键因子；6株菌的组合发酵实验揭示了体外系统与原位系统具有相同的微生物演替现象与相似的风味轮廓。【结论】研究揭示了青稞酒发酵过程关键的风味功能微生物以及驱动该菌群演替的重要环境因子，并通过组合发酵实验验证了这些微生物的风味代谢特征，为青稞酒发酵过程的风味调控提供了新的视角。

关键词:青稞酒，高通量测序，风味功能微生物，风味代谢

Abstract:

[Background] Highland barley Baijiu is a product of multispecies solid-state fermentation. It is important to regulate the fermentation of highland barley Baijiu through analyzing the important functional microbiota and their metabolic characteristics. [Objective] The purpose of this study was to reveal the flavor-related microbiota during highland barley Baijiu fermentation and resolve their co-metabolism. [Methods] the diversity and composition of microbial community during highland barley Baijiu fermentation were revealed by high-throughput sequencing. the flavors of fermented grains were detected by HS-SPME-GC-MS. Then flavor-related microbiota during highland barley Baijiu fermentation was revealed by correlation analysis between microbes and flavors. The effect of physical and chemical factors to the flavor-related microbiota was revealed by the Mantel test. the simulated fermentation with six strains under laboratory conditions was carried out to resolve their co-metabolism. [Results] nine dominant fungus and eight dominant bacteria (relative abundance>1%) were found during highland barley Baijiu fermentation. Aspergillus, Komagataella, Lactobacillus, Pichia, Saccharomyces and Weissella were identified as flavor-related microbiota. Reducing sugar (r2=0.946 9, P=0.013 2) and acidity (r2=0.847 6, P=0.048 6) were determined as key factors driving the succession of the flavor-related microbiota. The simulated fermentation with six strains revealed the in vitro system had the same microbial succession and flavors structure as the in situ system. [Conclusion] This work revealed the flavor-related microbiota and key factors driving their succession, and verified the metabolic characteristics of flavor-related microbiota by simulated fermentation. These results might provide a new perspective for regulating flavors information during highland barley Baijiu fermentation.

Key words:Highland barley Baijiu, High throughput sequencing, Flavor-related microbiota, Flavor metabolism