Characterization of L-(+)-Lactic Acid Producing Weizmannia coagulans Strains from Tree Barks and Probiogenomic Evaluation of BKMTCR2-2

Abstract

This study aimed to isolate and identify L-(+)-lactic acid-producing bacteria from tree barks collected in Thailand and evaluate the potential strain as probiotics. Twelve strains were isolated and characterized phenotypically and genotypically. The strains exhibited a rod-shaped morphology high-temperature tolerance and the ability to ferment different sugars into lactic acid. Based on 16S rRNA gene analysis all strains were identified as belonging to Weizmannia coagulans. Among the isolated strains BKMTCR2-2 demonstrated exceptional lactic acid production with 96.41% optical purity 2.33 g/l of lactic acid production 1.44 g/g of lactic acid yield (per gram of glucose consumption) and 0.0049 g/l/h of lactic acid productivity. This strain also displayed a wide range of pH tolerance suggesting suitability for the human gastrointestinal tract and potential probiotic applications. The whole-genome sequence of BKMTCR2-2 was assembled using a hybridization approach that combined long and short reads. The genomic analysis confirmed its identification as W. coagulans and safety assessments revealed its non-pathogenic attribute compared to type strains and commercial probiotic strains. Furthermore this strain exhibited resilience to acidic and bile conditions along with the presence of potential probiotic-related genes and metabolic capabilities. These findings suggest that BKMTCR2-2 holds promise as a safe and effective probiotic strain with significant lactic acid production capabilities. ? 2023 The Korean Society for Microbiology and Biotechnology.