Bioprospecting of marine derived actinomycetes with special reference to antimycobacterial activity

Abstract

Present study consists the bioprospecting of marine actinomycetes with special reference to antimycobacterial activity. Totally 49 actinomycetes were isolated from sediment samples collected from mangrove area of Pitchavaram coastal areas of Parangipettai and Andaman &amp; Nicobar Islands and by using starch casein agar medium. Based on the cultural and microscopic characteristics, 30 isolates were identified as <i style="">Streptomyces </i>sp. and 19 as rare actinomycetes including 11 <i style="">Micromonospora </i>sp. Bioactive substance from all the isolates were produced by shake flask fermentation method using yeast extract malt extract broth. Culture filtrate and mycelial methanol extracts were tested against drug sensitive and drug resistant clinical isolates of <i style="">M. tuberculosis</i> and standard strain <i style="">Mycobacterium tuberculosis</i> H37Rv by luciferase reporter phage (LRP) assay. Culture filtrate and/or mycelial methanol extracts from 41 out of 49 actinomycetes inhibited at least one of the <i style="">M. tuberculosis</i> strains tested. Culture filtrates from actinomycetes strains viz., R6 (<i style="">Streptomyces</i> sp), M1A6 (<i style="">Micromonospora</i> sp), M1A15 (<i style="">Actinosynnemma</i> sp), M1A18 (<i style="">Micromonospora</i> sp) and M1A23 (rare actinomycete) showed more than 90% reduction in RLU by LRP assay. Isolation of active compounds from these potent strains probably would lead to the discovery of novel antiTB drugs.