Assessment of the safety and probiotic properties of Lactiplantibacillus plantarum HYY-DB9 based on comprehensive genomic and phenotypic analysis

Lactiplantibacillus plantarum HYY-DB9 (LP. DB9) was isolated from traditional Chinese fermented pickles. In this study, genomics and phenotypic experiments was investigated to comprehensively analyze the safety and probiotic characteristics of LP. DB9. Whole genome sequencing revealed a genome size of 3,387,787 bp with a total of 3269 genes spanning 2,827,224 bp in length, accounting for approximately 83.45% of the total genome length. The average Guanine + Cytosine (G + C) content was determined to be 45.47%. By conducting antibiotic resistance tests and detecting harmful metabolites produced by LP. DB9, combined with analysis of antibiotic resistance genes, virulence factors and harmful metabolite-related genes, we have preliminarily demonstrated the safety profile of LP. DB9 as a strain suitable for probiotic applications. Furthermore, through tolerance assays including stress response gene analysis and adhesion gene evaluation using in vitro models simulating the human gastrointestinal tract as well as adhesion-related assays, we have identified favorable probiotic properties associated with LP. DB9's ability to withstand adverse conditions and adhere effectively within the gut environment. Additionally, three antimicrobial gene clusters were detected through comprehensive genome mining tools analysis further highlighting the potential use of LP. DB9 as a promising candidate for probiotics.