Construction and metabolomics of silage-derived lactic acid bacteria-based consortia

Abstract

Aims: The objective of this study was to construct and analyze the metabolomics of silage-derived lactic acid bacteria (LAB)-based consortia.

Methods and results: The LAB strains were isolated from various silages, and LAB-based consortia with different types of biodiversity were constructed by a bottom-up approach. Two hundred and ninety-two LAB strains were isolated, nine of which were selected as representative strains. Subsequently, five LAB consortia with diverse biodiversity levels (ranging from 4 to 8 species) were constructed. This construction was based on two key factors: the absence of antagonism among strains and their acidification capabilities, which were characterized by pH values (3.60-3.71), lactate (23.6-26.4 g l-1), and acetate (6.68-9.04 g l-1). Further fermentation experiments demonstrated that the five LAB consortia exhibited superior performance compared to alfalfa fermented green juice. Untargeted metabolomics was employed to analyze the differentially abundant metabolites and metabolic pathways of LAB consortia. Notably, 6 amino acids and 5 B-group vitamins varied among five LAB consortia, and key metabolic pathways were related to amino acids and vitamins for the LAB consortia.

Conclusions: Five LAB consortia with high acidification ability were constructed. The primary metabolic differences observed among the LAB consortia were the levels of 6 amino acids and 5 B-group vitamins.

Keywords: biodiversity; lactic acid bacteria consortia; metabolites; silage.