宏基因组学和代谢组学揭示了发酵马奶中微生物群落、代谢物和生物活性之间的相关性

摘要(中文译文)

马奶酒具有抗氧化、降血糖和降血压等多种功能特性；然而，自然发酵存在微生物群落结构不可控、产品质量波动大以及缺乏专用发酵剂等问题。自然发酵与接种发酵体系中微生物群落、功能性代谢物与生物活性之间关联的机制尚不清楚。因此，本研究采用生物活性测定、宏基因组学和非靶向代谢组学，系统分析了不同发酵方式下马奶的微生物群落、代谢物组成和功能活性的差异。结果表明，与自然发酵相比，混合乳酸菌（LAB）接种发酵显著增强了马奶的抗氧化、α-葡萄糖苷酶抑制、α-淀粉酶抑制活性以及ACE抑制活性；发酵样品的微生物多样性显著降低，其中接种组的降低更为明显。代谢组学分析表明，接种发酵显著富集了脂质和有机酸等功能性代谢物。相关性分析表明，Lactiplantibacillus和Limosilactobacillus的丰度与有益代谢物（如亚油酸、α-亚麻酸）及功能活性呈显著正相关。脂质和氨基酸代谢途径与接种发酵马奶体外生物活性的差异密切相关。本研究提供了一种能够提高马奶体外功能活性的发酵剂，揭示了乳酸菌发酵与马奶功能特性改变之间潜在的代谢联系，从而为高附加值发酵马奶产品的开发提供了理论依据和技术支持。

Abstract

Koumiss exhibits various functional properties, including antioxidant, hypoglycemic, and antihypertensive effects; however, natural fermentation is characterized by an uncontrollable microbial community structure, significant fluctuations in product quality, and a lack of specialized fermentation agents. The mechanisms underlying the links between microbial communities, functional metabolites, and bioactivity in natural and inoculated fermentation systems remain unclear. Therefore, this study employed bioactivity assays, metagenomics, and non-targeted metabolomics to systematically analyze differences in microbial communities, metabolite composition, and functional activities of mare's milk under different fermentation regimes. The results indicated that, compared with natural fermentation, inoculated fermentation with a mixed lactic acid bacteria (LAB) culture significantly enhanced the antioxidant, α-glucosidase, α-amylase inhibitory activities, and ACE inhibitory activity of mare's milk; microbial diversity in fermented samples was significantly reduced, with a more pronounced decrease in the inoculated group. Metabolomic analysis revealed that inoculated fermentation significantly enriched functional metabolites, including lipids and organic acids. Correlation analysis indicated that the abundance of Lactiplantibacillus and Limosilactobacillus was significantly positively correlated with beneficial metabolites (e.g., linoleic acid, α-linolenic acid) and functional activities. The lipid and amino acid metabolic pathways are closely associated with the differences in in vitro biological activity of inoculated fermented mare's milk. This study provides a fermentation starter that can improve the in vitro functional activity of mare's milk and reveals the potential metabolic links between LAB fermentation and the altered functional traits of mare's milk, thereby providing a theoretical basis and technical support for the development of high-value-added fermented mare's milk products.

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