Assessment of tolerance to multistresses and in vitro cell adhesion in genetically modified Lactobacillus plantarum 590

Lactobacillus plantarum (Lp) is a lactic acid bacterium that has many excellent traits that meet the needs of industrial production. Genetically modified (GM) Lp590 was obtained from Lp that was modified by the insertion of the gene nisI, which can confer resistance to nisin and play a role as a bio-preservative. Here, explorations were made to assess the safety of GM Lp590 and establish an in vitro evaluation model. The ability of Lp590 to tolerate both environmental stresses (such as temperatures ranging from 52 to 4°C, or exposure to ethanol, oxygen, and osmotic stresses) and gastrointestinal transit was assessed. Lp590 showed a tolerance to 4°C and ethanol (20%) within a period of 240 min that was similar to Lp. Notably, Lp590 can tolerate higher temperature (52°C) and higher levels of H2O2 (2%) and NaCl (4.0 M) than Lp. In contrast, Lp590 has the same gastrointestinal transit tolerance as Lp. In addition, Lp590 can adhere to Caco-2 cells, and it has no adverse effect on the cell membrane in vitro. These results indicate that GM Lp590 has many desirable biological characteristics and has good prospects for industrial applications. A useful and comprehensive exploration has been undertaken to establish a new in vitro evaluation model for genetically modified microorganisms (GMMs).