谷物蛋白对白酒发酵过程中微生物群落及其代谢多样性的调控

Regulation of cereal protein on the microbial and metabolic diversity during the Chinese liquor fermentation

摘要:

[背景] 在白酒发酵过程中，原料中的谷物蛋白可为微生物的生长提供氮源等营养物质，进而形成多种代谢产物。谷物蛋白可分为清蛋白、球蛋白、醇溶蛋白和谷蛋白。然而，谷物蛋白对微生物多样性及其代谢产物多样性的调控尚不明确。[目的] 揭示白酒发酵过程中与微生物多样性及其代谢产物多样性显著相关的关键谷物蛋白种类及其调控作用。[方法] 通过Osborne法测定不同品种高粱中谷物蛋白的组成；采用多组学联用技术解析4种高粱在发酵过程中的微生物菌群多样性及代谢产物多样性；通过模拟发酵揭示原料中影响微生物群落及其代谢多样性的关键蛋白。[结果] 4种高粱中的谷物蛋白组成存在显著差异（ANOSIM：R=0.85，P=0.001）；4种高粱在发酵第5天时，S4高粱的细菌多样性显著（P<0.05）高于其他3种高粱，S3高粱中微生物的代谢产物多样性显著（P<0.05）高于其他3种高粱；清蛋白和球蛋白含量与发酵第5天的优势细菌多样性（R²=0.34，P<0.05；R²=0.58，P<0.05）和代谢产物多样性呈显著正相关（R²=0.58，P<0.05；R²=0.36，P<0.05），被定义为关键蛋白；模拟发酵实验验证了优势细菌多样性和代谢产物多样性可随着2种关键蛋白即清蛋白和球蛋白含量的升高而升高。当清蛋白含量在3.0 g/L时，优势细菌多样性及代谢产物多样性可分别达到0.72和0.65；当球蛋白含量在3.0 g/L时，优势细菌多样性及代谢产物多样性可分别达到0.66和0.81。[结论] 研究揭示了酿造原料中的清蛋白和球蛋白对发酵过程中细菌多样性及代谢产物多样性的调控作用，为提高白酒发酵的可控性及质量提供了依据。

Abstract:

[Background] Cereal protein of raw material can provide nutrients such as nitrogen sources for the growth of microbial community, and then form a variety of metabolites during Chinese liquor fermentation. Cereal protein includes albumin, globulin, kafirin and gluten. However, the regulation of cereal protein on microbial diversity and metabolic diversity is still unclear. [Objective] This study aimed to reveal the key cereal protein that are significantly related to microbial diversity, and the effect of their regulation on microbial diversity and metabolic diversity. [Methods] The cereal protein was determined by Osborne's method; Identification of microbial diversity and metabolic diversity via HS-SPME-GC-MS and high-throughput sequencing during fermentation with 4 cultivars of sorghum. The key cereal protein was verified by simulated fermentation in vitro. [Results] The cereal protein of 4 sorghum was significant difference (ANOSIM:R=0.85, P=0.001); The bacterial diversity of sorghum S4 was significantly higher than others (P<0.05) at day 5 of fermentation with 4 sorghum; The metabolic diversity of sorghum S3 was significantly higher than others (P<0.05) at day 5 of fermentation with 4 sorghum. The contents of albumin and globulin were significantly correlated with the dominant bacterial diversity (R²=0.34, P<0.05; R²=0.58, P<0.05) and metabolic diversity (R²=0.58, P<0.05; R²=0.36, P<0.05) at day 5 of fermentation. Thus, they are defined as the key cereal protein; In vitro validation confirmed that the dominant bacterial diversity and metabolic diversity would increase with the increase of albumin and globulin content. When the albumin content is 3.0 g/L, the dominant bacteria diversity and metabolite diversity are 0.72 and 0.65, respectively; when the globulin content is 3.0 g/L, the dominant bacterial diversity and metabolite diversity are 0.66 and 0.81, respectively. [Conclusion] The study revealed the regulation of albumin and globulin in raw material on the diversity of bacteria and metabolites, and providing a new perspective for improving the controllability and quality of Chinese liquor fermentation.