Molecular identification, L-lactic acid production, and antibacterial activity of Bacillus strains isolated from soilsVasana Tolieng, Auttaporn Booncharoen, Ratthanatda Nuhwa, Nuttha Thongchul, Somboon Tanasupawat.
Fourteen spore-forming bacteria isolated from soils were evaluated for their taxonomic characterization, lactic acid production and antimicrobial activity. They were belonged to the genus Bacillus and were closely related to Bacilus coagulans LMG 6326T with 97.64-98.48 % similarity, based on 16S rRNA gene analyses. Repetitive genomic element-PCR (Rep-PCR) fingerprinting using the primers sets; BOX-PCR, ERIC-PCR, GTG-PCR and REP-PCR were used to differentiate among the species. Clustering of the isolates with the PCR fingerprint dendograms obtained two groups. Group 1 consists of two isolates, JC3 and JC11 (16.67%), and the rest ten isolates (83.33%) were distributed in another groups. Based on 16S rRNA sequence analysis and Rep PCR and the phenotypic characteristics, they were classified as a novel Bacillus species. These isolates were screened for lactic acid production and antimicrobial efficiency, and the results revealed that they produced L-lactic acid in the ranged of 1.7±0.1-32.6±0.7 g/L at 98.58±0.06-100.00±0.00 % optical purity. Among them, only JC19 was found to show inhibitory activity against Kocuria rhizophila ATCC 9341.
Bacillus, Rep-PCR, lactic acid, antibacterial activity, soil