Enhancement of Pediocin Production in Pediococcus pentosaceus SNSS18 by Exogenous Amino Acids and Nucleobases: A Mechanistic Elucidation

Amino acids and nucleobases, as essential nutrients for lactic acid bacteria (LAB), play a pivotal role in their growth and metabolism. However, their specific effects on pediocin production and the underlying regulatory mechanisms have not yet been elucidated. This study aimed to identify exogenous amino acids and nucleobases that enhance pediocin production by Pediococcus pentosaceus SNSS18, and further analyze their induction mechanisms. Alanine, cysteine, aspartate, methionine, adenine, and uracil significantly promoted pediocin production (p < 0.05), achieving a maximum increase of 60.75% in antibacterial activity compared with the control. Genomic analysis revealed the presence of the pediocin PA-1 biosynthesis operon (pedABCD) and the LuxS/AI-2 quorum-sensing (QS) system in P. pentosaceus SNSS18. Notably, methionine (0.5 g/L), cysteine (0.5 g/L), aspartate (1 g/L), and uracil (1.5 g/L) enhanced AI-2 signal activity and upregulated the expression of key QS genes (luxS and pfs), suggesting that their promotive effects are likely linked to the LuxS/AI-2 QS system. Exogenous supplementation with AI-2 further verified that the LuxS/AI-2 QS system is a key pathway regulating pediocin production in P. pentosaceus SNSS18. However, the regulatory mechanisms underlying the promotive effects of alanine and adenine remain to be elucidated. These findings provide new insights into the regulation of pediocin biosynthesis and highlight the potential of exogenous amino acid and nucleobase supplementation to markedly enhance pediocin production for food biopreservation, while supporting the development of P. pentosaceus SNSS18 as a probiotic strain.