The metabolites of lactic acid bacteria: classification, biosynthesis and modulation of gut microbiota

Abstract

Lactic acid bacteria (LAB) are ubiquitous microorganisms that can colonize the intestine and participate in the phys-iological metabolism of the host. LAB can produce a variety of metabolites, including organic acids, bacteriocin, amino acids, exopolysaccharides and vitamins. These metabolites are the basis of LAB function and have a profound impact on host health. The intestine is colonized by a large num-ber of gut microorganisms with high species diversity. Me-tabolites of LAB can keep the balance and stability of gut microbiota through aiding in the maintenance of the intes-tinal epithelial barrier, resisting to pathogens and regulat-ing immune responses, which further influence the nutri-tion, metabolism and behavior of the host. In this review, we summarize the metabolites of LAB and their influence on the intestine. We also discuss the underlying regulatory mechanisms and emphasize the link between LAB and the human gut from the perspective of health promotion.