Abstract:Peptidoglycan is an essential component of the cell wall of lactic acid bacteria, its chemical structure is mainly conservative and constant, and its biosynthesis is a complex process involving multi-step reactions. Peptidoglycan of lactic acid bacteria exhibits various biological activities, such as immune-enhancing functions, anti-infection, anti-tumor, and anti-anaphylaxis. In this review, the composition, structure and biological activity of peptidoglycan of lactic acid bacteria are outlined, the research development in metabolism and regulation of peptidoglycan is reviewed emphatically, and the direction to the future study of lactic acid bacteria peptidoglycan is proposed as well.