Whole Genome Analysis of Levilactobacillus brevis PL6-1 and Assessment of Its Safety and Antioxidant Activity

This study utilized the second-generation NovaSeq X Plus and third-generation PacBio Revio sequencing platforms for the whole-genome sequencing of Levilactobacillus brevis PL6-1, isolated from traditional fermented vegetables in China. Based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, the carbohydrate metabolic pathways of L. brevis PL6-1 were reconstructed, and the safety of this strain was assessed. Additionally, the effects of different carbon sources on its antioxidant activity were analyzed. The results showed that the genome size of L. brevis PL6-1 was 2632919 bp, with 2618 coding genes being annotated in the Non-Redundant Protein Database. The genome was rich in genes encoding enzymes of the glycoside hydrolase (GH) family, but neither antibiotic resistance nor virulence genes were found. Phenotypic analysis revealed that L. brevis PL6-1 exhibited no hemolytic activity and demonstrated resistance to kanamycin, gentamicin, and vancomycin. In addition, L. brevis PL6-1 was able to utilize L-arabinose, ribose, D-xylose, galactose, glucose, fructose, salicin, maltose and trehalose. Maltose rapidly initiated the proliferation of L. brevis PL6-1. Furthermore, when cultured with trehalose or glucose as the primary carbon source, L. brevis PL6-1 demonstrated enhanced 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, while culture with ribose as the primary carbon source increased the 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) cation radical scavenging capacity. The findings from this study provide a significant theoretical basis for the safe application of this strain in the food industry while establishing a scientific foundation for the development and utilization of its probiotic functions.