Bioactive metabolites produced from Streptomyces enissocaesilis SSASC10 against fish pathogens

In this study Marine pigment producing actinobacteria were screened for bioactive metabolite against fish pathogens. Totally ten morphologically different actinobacteria was isolated from sediment sample of Mudasalodai, Chidambaram, India. The isolates were preliminary tested for antibacterial activity by agar plug method against Pseudomonas sp, Vibrio anguillarum, Aeromonas hydrophilia, Vibrio paraheamolyticus and Vibrio harveyi. The brown pigment producing isolate SSASC found to inhibit all the tested fish pathogens and hence selected for further study. The bioactive metabolite was extracted using different solvents such as methanol, chloroform, ethyl acetate and n-hexane in which ethyl extract showed promising antibacterial activity. The minimum inhibitory concentration (MIC) of the ethyl acetate extract ranged from 15.6 mu g/ml to 125 mu g/ml and minimum bactericidal concentration (MBC) found to be in the range of 62.5 mu g/ml to 250 mu g/ml. The ethyl acetate extract was purified using TLC and a single spot with Rf value of 0.45 was observed in TLC. The FT-IR spectrum exhibits characteristic signals at 16 peaks corresponding to functional groups indicating phosphenes, amino acids, and presence of alkyl ether. GC-MS analysis of brown pigment from SSASC showed 25 peaks. The potent strain SSASC10 was identified as Streptomyces enissocaesilis based on morphological, biochemical and molecular characteristics. In this present finding, the isolated Streptomyces enissocaesilis SSASC10 strain found to have excellent antibacterial activity against fish pathogens hence can be used for treating infectious fish disease.