Bioengineering of a Lactococcus lactis subsp. lactis strain enhances nisin production and bioactivity.

Abstract

Lactococcus lactis subsp. lactis is a food bacterium that has been utilized for decades in food fermentation and the development of high-value industrial goods. Among these, nisin is produced by several strains of L. lactis subsp. lactis plays a crucial role as a food bio-preservative. The relative expression of the gene cluster involved in nisin production was evaluated using qPCR analysis. Additionally, a series of re-transformations of the strain introducing multi copies of the nisA and nisRK genes involved in nisin biosynthesis were developed. The simultaneous expression of nisA and nisZ genes was used to potentiate the effective inhibition of foodborne pathogens. Further, qPCR analysis revealed a low expression of the nisA and nisRK genes in wild-type L. lactis subsp. lactis. After several re-transformations of the strain with the nisA and nisRK genes, a high expression of these genes was obtained, contributing to improved nisin production. Also, the co-expression of nisA and nisZ genes results in highly efficient antimicrobial activity. Hence, this study would supply an approach to enhancing nisin production during industrial processes and antimicrobial activity.