Abstract

Objective: To investigate the antibacterial potential of the marine actinomycetes isolated from sponge samples. Methods: Thirty six marine sponge samples were collected from Palk Strait and further used for actinomycetes isolation by using serial dilution. The antibacterial activity was carried out by using cross streak assay method. Moreover, most potential strain also subjected to MIC and MBC techniques and the isolated potential strain was identified by molecular tools. Results: The maximum counts (26 x 102 CFU/g) were observed in the month of May and minimum counts (1 x 102 CFU/g) were noticed in April. A total of 21 actinomycetes were isolated and their antibacterial potential was assessed by using cross streak method. Among the 21 actinomycetes, the ACT-21 showed sensitivity against all the isolated fish pathogens. Further, the MIC and MBC results reveal that, the ACT-21 showed sensitivity at the concentration ranged between 500 毺 g/ mL-1 500 毺 g/mL. The phylogenetic analysis suggested that, the potential isolate ACT-21 (accession no: JF899543) showed maximum similarity index (>98%) with Streptomyces sp. Conclusions: It is concluded from present study that, the crude extracts of sponge associated actinomycetes could be used as an effective antibacterial agent for the management of disease free fish culture system.

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