Characterization of Marine Streptomyces carpaticus and Optimization of Conditions for Production of Extracellular Protease

摘要

A black pigmented, proteolytic actinomycete strain was isolated from a marine sediment sample collected near Kakinada of Andhra Pradesh province, India. The isolate grows to produce circular colonies that had yellow-white substrate mycelium and grey aerial mycelium on Starch Casein Agar, with black diffusible pigment. Its proteolytic activity was indicated by growth and clear zone appearance on casein-skim milk agar media plate. Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain belongs to the genus Streptomyces, with the highest similarity to Streptomyces carpaticus NBRC15390~T (99.6%). On the basis of polyphasic evidence, the strain was recognized as a new isolate of Streptomyces carpaticus from marine source. Optimal conditions for protease production by Streptomyces carpaticus were; incubation temperature of 35°C, pH 7.0, inoculum size 6% (v/v) and agitation speed of 150 rpm. The best carbon, organic nitrogen and inorganic nitrogen sources for production of proteaseenzyme were glucose, soybean meal and ammonium sulfate, respectively. Under these conditions the newly isolated strain produced protease activity of 17542.51 U mL~(-1). This is the first report on protease production by Streptomyces carpaticus from marine source.