Selection of Marine Actinomycetes with Bioactive Potential Isolated from Sediments of Bay of Bengal and Characterization of Promising Isolate, ABT-103

Abstract

Aim: Marine actinomycetes are a potential and untapped source for the production of novel bioactive compounds. The aim of the present work is to isolate actinomycetes strains from the marine sediments of Bay of Bengal for the production of bioactive compounds and characterization of the potential actinomycetes. Place and Duration of Study: Department of Chemical Engineering and Biotechnology, ANITS, Visakhapatnam, between March, 2014 and April­­­­­­­­­­­­­­­­­­­­­­, 2015.­ Materials and Methods: Marine sediment samples were collected along the coast of Bay of Bengal, Visakhapatnam, India. Actinomycetes were isolated on Starch Casein Agar plates by pour plate and spread plate methods. Morphologically distinct pure isolates were tested for antimicrobial activity by Cross-streak method in preliminary screening and by Cup-plate method in secondary screening. The marine isolates were also screened for enzyme activities of amylase, lipase, protease and L-asparaginase. The most potential isolate was characterized up to genus level based on morphological, chemotaxonomic, biochemical and physiological characteristics. Results: A total of 74 bacterial strains were isolated from marine sediment samples of Bay of Bengal. Among them, 13 morphologically distinct pure isolates were screened for antimicrobial activity and also for enzyme activities. Five isolates exhibited antimicrobial activity among which ABT-205 isolate showed broad spectrum antimicrobial activity against both bacteria and fungi, and ABT-103 exhibited maximum antifungal activity. Screening for enzyme activities revealed that nine isolates exhibited enzyme activities of which, ABT-101 and ABT-201 are highly potential for the production of Protease, whereas ABT-103 and ABT-206 were best producers of Amylase and Lipase enzymes, respectively. Among all the isolates screened, ABT-103 was found to be a promising isolate as it produced red pigment, exopolysaccharide, amylase and exhibited antifungal activity. Hence, the isolate ABT-103 was characterized and identified as Streptomycesspecies. Conclusion: The selected marine actinomycetes isolates, ABT-101, ABT-103, ABT-201, ABT-205 and ABT-206 could be useful or the production of novel antibiotics, enzymes with different physical and physiological properties, red pigment, exopolysaccharide and other compounds for various Biotechnological applications.