Optimization and multiomic basis of phenyllactic acid overproduction by Lactobacillus plantarum

The goal of this study was to explore the regulatory mechanisms of phenyllactic acid (PLA) overaccumulation in Lactobacillus plantarum. The dynamics of PLA production revealed that 24 h was a suitable fermentation time, at which one of the largest differences in PLA content between strains S1 and YM-4-3 was 22.42 mg/L. Additionally, an optimization experiment showed that PLA production under the optimal condition (sample YM-4-3y) was up to 400.74 mg/L, 7.61–13.26 times as those of YM-4-3 and S1. Subsequently, an integrated analysis of genomic, transcriptomic and metabolomic data revealed that, YM-4-3 and YM-4-3y, compared with S1, although lacking a complete de novo biosynthetic pathway, increased PLA production by strengthening the core pathway and central carbon metabolism, and weakening the biosynthesis pathway of amino acids and their derivatives. These changes can provide sufficient precursors and compensate for or balance the energy consumed by the reinforced core pathway.