Isolation and characterization of actinobacteria effective against multidrug resistant pathogens and their bioactive metabolites

Abstract

Actinobacteria are the most widely distributed organism in the mangrove environment and produce a large amount of secondary metabolites. Mangrove ecosystems are among the worlds for the most productive ecosystem that yields commercial natural products. In this view, the current study to investigate to isolate actinobacteria from the various mangrove sediments; as source of actinobacteria from the mangrove wet soil. Totally 144 actinobacteria were isolated from soil samples, of which 38 isolates (26.38%) were exhibited antimicrobial activity. Primary screening was done using by cross streak method against Multi Drug Resistant Staphylococcus aureus (MDRSA). The active producer strain was found out to be Brevibacillus brevis EGS9 by morphological, biochemical characteristics and 16S rRNA gene sequencing. Molecular characterization included 16S rRNA sequencing analysis and phylogenetic tree construction. The polymerase newlineChain Reaction (PCR) amplification of isolate Brevibacillus brevis EGS9 16S rRNA gene sequencing yielded 760 base pair and BLAST analysis of Brevibacillus brevis EGS9 showed 99% similarity with Brevibacillus sp. (KF479681). It was deposited in NCBI GeneBank database with accession number of KX388147. Strain Brevibacillus brevis EGS9 was selected as a potential strain for its promising activity when compare with other isolated strains. Strain Brevibacillus brevis EGS9 showed optimized antimicrobial compound production and bioactivity in submerged fermentation, cultivated by submerged fermentation to produced antimicrobial compounds while compared to agar surface fermentation. The bioactive metabolites were extracted from Brevibacillus brevis EGS9 using ethyl acetate extraction. newline newline