Deep sea bacterial diversity and bioprospecting potentials of piezotolerant streptomyces species

Abstract

The deep sea is a largely unexplored, pristine environmental niche which harbours newlinediverse microbes holding intricate secondary metabolism. To explore the bacterial diversity newlineand to unravel its bioactive potential deep sea sediment samples were collected from Bay of newlineBengal and Andaman Sea through Research Vessel Sagar Manjusha Cruise organized by the newlineNational Institute of Ocean Technology, Chennai. Bacterial diversity profiles of the sediments newlinesamples were achieved by performing Denaturing Gradient Gel Electrophoresis (DGGE) newlinethrough fingerprinting approach. A culture based diversity study was devised and several newlinedifferent bacterial species were isolated and taxonomically classified into 34 different OTUs newline(Operational Taxonomic Unit). All the representative strains from 34 OTUs were screened for newlinedifferent types of hydrolase enzyme and antimicrobial compound production. With this newlinebackground the genus Streptomyces was concluded to show good bioactivity.Initial screening for biosynthetic genes like polyketide synthase I (PKS I),polyketide synthase II (PKS II), non ribosomal peptide synthase (NRPS), 3-amino-5-hydroxybenzoic acid (AHBA) synthase and spiroindimicin followed by in vitro antibacterial assay confirmed the presence of bioactive secondary metabolites from the strain designated as Streptomyces sp. NIOT-Ch-40 which was isolated from deep sea sediment of Bay of Bengal (2000 m depth).The strain showed a specific antagonistic property against gram-positive potentialhuman pathogens including methicillin-resistant Staphylococcus aureus (MRSA). The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the ethyl acetate extract against the MRSA was 1.5 and#956;g/mL, which was statistically newlinesignificant in comparison with the control drug erythromycin. newline newline