Marine actinomycetes

The present study deals with the isolation, screening and characterization of the actinomycetes from the marine sediments, which were collected from different locations of Bay of Bengal. Selective media and the pre-treatment strategies enhanced the isolation and screening of novel marine actinomycetes. A total of 8 marine samples were collected. The pre-heat treatment method and a combination of 4 enrichment media were found to be effective in selectively isolating marine actinomycetes. The top six potent isolates were subjected to detailed morphological, cultural, biochemical and physiological characterization. A total of 63 isolates were isolated. The antimicrobial activity was studied for all the 63 isolates. The preliminary study of 63 isolates for antimicrobial activity by cross streak method indicated that 42 isolates had antagonistic properties. All these 42 isolates were subjected to submerged fermentation studies. It was observed that 12 isolates exhibited antibacterial activity, 6 isolates showed antifungal activity whereas 6 isolates exhibited both antibacterial and antifungal activities. The present study was an attempt to use different methods to screen, select and isolate marine actinomycetes from the sediments of Bay of Bengal with intrinsic antimicrobial activity against a variety of microbial pathogens.

A total of fifty six actinomycete isolates were isolated from the ten marine sediments of south India. Marine environment is a potential source of novel actinomycetes, which are a potent source of antibiotics and novel bioactive compounds. The isolates were identified as actinomycetes by morphological, biochemical and microscopic studies. The isolated actinomycetes were screened for L-asparaginase activity by rapid plate assay method. Based on screening, isolate 1, 2 and 18 were showed large clear pink zone and its diameter (dm) was measured as 9.0, 8.5 and 8.5 cm and the enzyme production has been determined by nesslerization method. The spectrophotometric assay of enzyme activity of the isolates 1, 2 and 18 were found to be 1.92, 1.48 and 1.46 U/ml.