Whole genome sequencing analysis and functional characterization of Lacticaseibacillus rhamnosus HP-B1083.

Lacticaseibacillus rhamnosus is an important strain for the biotransformation of natural products, and its crude extract exhibits biotransformation effect on glycosidic compounds such as baicalin. To further explore the potential of this strain, particularly given its previously demonstrated high-efficiency β-glucuronidase activity for baicalin conversion, whole-genome sequencing and functional annotation of Lacticaseibacillus rhamnosus HP-B1083 were performed in this study, and its acid tolerance, bile salt tolerance, short-term heat resistance and antibacterial activity were evaluated. The results showed that the strain possessed a circular chromosome with a full length of 3,090,505 bp and a GC content of 46.69%. Gene annotation revealed that the genome contained 2941 coding sequences (CDS) and 112 non-coding RNA genes, including 60 tRNA genes, 1 tmRNA gene, 36 misc_RNA genes and 15 rRNA genes. The functional annotations further reveal that this genome is rich in genes related to carbohydrate metabolism, hydrolases, and transferases, which is highly consistent with its phenotypic characteristics in glycoside transformation and the synthesis of antibacterial substances. In addition, acid tolerance, bile salt tolerance and short-term heat resistance experiments verified that HP-B1083 had acid resistance, bile salt resistance and short-term heat resistance. Antibacterial activity tests confirmed that HP-B1083 produced inhibition zone diameters over 10 mm against common foodborne pathogenic bacteria such as Escherichia coli and Bacillus cereus. Therefore, Lacticaseibacillus rhamnosus HP-B1083 has important application prospects in the development of functional foods, preparation of enzyme preparations and pharmaceutical industry.