Taxonomic Profile and Antimicrobial Potential of Brachybacterium conglomeratum VLCH–15 Isolated from Mangroves of Machilipatnam, Andhra Pradesh, India

Abstract

Actinobacteria of mangrove origin become a vital source of novel antibiotics with high therapeutic potential. Hence, the current study has been focused on antimicrobial potential of secondary metabolites produced by rare actinobacterium isolated from mangrove ecosystem of Machilipatnam, Andhra Pradesh, India. Sediment samples collected from mangrove habitats were shade dried at room temperature. The samples were employed for isolation of actinobacteria by serial dilution followed by spread plate method. Yeast extract malt extract dextrose (YMD) agar, starch casein agar (SCA), actinomycetes isolation agar (AIA) and humic acid vitamin agar (HV) media amended with NaCl @ 3% were employed for isolation of actinobacteria. A total of 15 actinobacterial strains were isolated and coded as VLCH-1 to VLCH-15. All the isolates were screened for their antimicrobial metabolite production against test bacteria and fungi. Out of 15 strains, VLCH-15 exhibited oad spectrum of antagonistic activity. Based on polyphasic taxonomic studies, the strain was identified as Brachybacterium conglomeratum VLCH-15. The growth curve and antimicrobial profile of B. conglomeratum VLCH-15were studied at regular intervals up to 10 days in batch culture. The secondary metabolites obtained from 7 days old culture showed high antimicrobial activity against X. campestris, E. coli and A. flavus. Among the fungi tested, Aspergillus flavus showed high sensitivity. Further studies on optimization, purification and characterization of bioactive metabolites of B. conglomeratum VLCH-15 are in progress. The bioactive compounds produced by this strain might have potential use in new antimicrobial therapy or drug design.