Diversity of culturable actinobacteria producing protease inhibitors from the intertidal zones of Maharashtra, India

Abstract

Phylogenetic diversity of culturable actinobacteria isolated from the intertidal regions of west coast of Maharashtra, India was studied using 16S rRNA gene sequencing. Total of 140 actinobacterial isolates were obtained, which belonged to 14 genera, 10 families and 65 putative species with Streptomyces being the most dominant (63%) genus followed by Nocardiopsis and Micromonospora. They were screened for production of extracellular protease inhibitors (PI) against three pure proteases viz. chymotrypsin, trypsin, subtilisin and one crude extracellular protease from Pseudomonas aeruginosa. Eighty percent of the isolates showed PI activity against at least one of the four proteases, majority of them belonged to genus Streptomyes. Actinobacterial diversity from two sites Ade (17{degrees}52' N, 73{degrees}04' E) and Harnai (17{degrees}48' N, 73{degrees}05' E) with varying degree of anthropological pressure showed that more putative species diversity was obtained from site with lower human intervention i.e Ade (Shannons H 3.45) than from Harnai (Shannons H 2.83), a site with more human intervention. Further, in Ade percentage of isolates not showing PI activity against any of the proteases was close to 21% and that in Harnai was close to 9%. Considering human activities in the coastal region might be contributing to increasing the organic load and in turn increasing the presence of extracellular enzymes in the intertidal environments it would be interesting to look at the association of PI production and organic load in these habitats.