Endophytic Paenibacillus amylolyticus KMCLE06 Extracted Dipicolinic Acid as Antibacterial Agent Derived via Dipicolinic Acid Synthetase Gene.

Bioactive natural compounds play pivotal roles in drug discovery and the emergence of multi-drug resistance pathogens demands the development of better/new drugs. Paenibacillus amylolyticus KMCLE06 endophytic bacterium isolated from the medicinal plant Coix lachryma-jobi were analyzed for the potential bioactive secondary metabolite compounds and its gene responsible within polyketide synthases (PKS) clusters. Ethyl acetate extraction of P. amylolyticus KMCLE06 showed significant antibacterial activity which was further processed to partial purification and characterization for bioactive compound. The foremost bioactive component in extraction was found to be dipicolinic acid (DPA). The antibacterial activity showed remarkable activity compared to the commercial standard DPA against both gram-positive and gram-negative pathogens. The MIC and MBC concentrations for partially purified extracted DPA ranged from 62.5 to 125 µg/ml and MBC from 208 to 250 µg/ml, respectively. Sequence analysis of gene amplified using degenerative primer, amplified 543 bp DNA region, revealing conserved putative open reading frame for dipicolinic acid synthetase (DpsA) key gene to produce DPA in most endospore forming bacteria. A search in the structural database for DpsA revealed significant homologous match with enoyl reductase one of the PKS type 1 module protein. This emphasizes endophytic P. amylolyticus KMCLE06 bacteria has presence of spoVF operon producing DPA via dipicolinic acid synthetase and lacks the polyketide synthase type 1 module cluster gene in its genome. And the bioactive compound DPA extracted acts as a stable remarkable antibacterial agent which can be potent compound for multi-resistance pathogens.