Secondary metabolites produced by Streptomyces parvulus Strain J6.2

Abstract

Streptomyces parvulus J6.2 was isolated from soil in a mangrove area and studied its metabolites. The morphology and 16S rDNA sequences were used to identify it as belonging to S. parvulus. Comparison of 16S rDNA sequences showed that S. parvulus J6.2 had a close relationship to the actinomycin-D producing Streptomyces species. Carbon utilization indicated that S. parvulus J6.2 was a novel strain. Actinomycin-D, a major bioactive component, was isolated from ethyl acetate crude extracts by reverse phase HPLC using isocratic of 30% methanol in water as the mobile phase with a 3 ml min-1 flow rate. The molecular structure of actinomycin-D was confirmed by 2D-NMR. Medium optimization gave the highest yield of 378.84 mg/l actinomycin-D when grown in a sodium caseinate broth supplemented with 20 g/l malt extract as the culture medium. Starch and malt extract supplemented culture medium produced high crude metabolite yield therefore increasing actinomycin-D production. High concentration of NaCl in culture medium suppressed production of triglyceride metabolites resulting in more specific production of actinomycin-D.