Genome, transcriptome and fermentation analyses of Lactobacillus plantarum LY-78 provide new insights into the mechanism of phenyllactate biosynthesis in lactic acid bacteria

Phenyllactate (PLA) is found in a variety of fermented foods and is a promising antibacterial agent, drug and plastic synthetic precursor. Previous studies have shown that PLA is a product of Phe catabolism in lactic acid bacteria (LAB), and PLA biosynthesis is mainly related to lactate dehydrogenases (LDHs). Here, the genome, transcriptome and fermentation characteristics of PLA-producing Lactobacillus plantarum LY-78 were studied. The fermentation experiments demonstrated that L plantarum LY-78 possesses the ability to synthesize PLA de novo. Secondly, the genome and transcriptome analyses revealed candidate pathways, operons and key genes for PLA biosynthesis in the strain. Finally, genome-wide transcriptome analysis revealed significant changes in the expression profile of strain LY-78 in the absence and presence of PPA. Overall, this work demonstrates for the first time that PLA can be a by-product of Phe anabolism in LAB, provides new insights and evidence for elucidating the mechanism of PLA biosynthesis in LAB, and may provide new candidate genes and research strategies for future PLA biosynthesis applications. (C) 2019 The Authors. Published by Elsevier Inc.