Metabolomic Profiling of Lactobacillus plantarum Isolated from Ocimum gratissimum Rhizosphere

L. plantarum is a known member of the lactic acid bacteria that possesses antimicrobial activities. Organic acids, hydrogen peroxide and bacteriocins have been majorly identified as the contributors to its antimicrobial activity. The present study sought to employ the GC-MS technique to further classify biological compounds that comprise the antimicrobial metabolite produced by L. plantarum through sub-merged fermentation. The bacterium was isolated from the rhizosphere of O. gratissimum and confirmed using molecular typing. Preliminary antibacterial screening of the organism was done with indicator strains isolated from urinary tract and wound surface, after which sub-merged fermentation was employed for the production of secondary metabolites for a 24 h period. The GC-MS technique was employed to identify the volatile bioactive compounds that comprise the secondary metabolite produced. The organism had significant (p<0.05) inhibition of the indicator strains when compared to the ciprofloxacin standard antibiotic. Metabolomics analyses identified Hydroxylamine, O-decyl-, 2,4-Di-tert-butylphenol, and a wide range of organic compounds mainly from the alkane, amine, carboxylic acids and phenol functional groups, as the components of its antibacterial metabolite. GC-MS based metabolomics analyses is a profitable tool for identifying key components of the antibacterial substance produced by L. plantarum as this will give a room for its bio-prospecting potentials as alternative and sustainable source of novel antimicrobial compounds and other beneficial medications used by humans.