Ultrasound induced production of thrombinase by marine actinomycetes: Kinetic and optimization studies

A potent fibrinolytic protease (thrombinase) was isolated from marine actinomycetes which can be used for the treatment of myocardial infarction. Thrombinase producing actinomycetes were isolated from the marine water sample using fibrin plate assay. The spore morphology of the marine isolate was analyzed by light and scanning electron microscopy (SEM). Further the marine isolate was identified as Streptomyces venezuelae through biochemical tests and 16srRNA analysis. Effect of ultrasonication on cell concentration and enzyme activity was further determined and the maximum values 20.62 mg mL−1 and 6.24 FU mL−1, respectively were obtained under static condition. The maximum specific growth rate μm (h−1) of the marine isolate under static condition was evaluated as 0.554 h−1 with ultrasonication by modified gompertz model using Matlab 7.0. Moreover effect of salinity on cell concentration and enzyme activity was also analyzed, the maximum biomass, 22.42 mg mL−1 and maximum enzyme activity, 6.7 FU mL−1 at 6% (w/v) salinity. Optimization was done further by response surface methodology (RSM) using central composite design (CCD) and it was found pH 7, temperature 35 °C and salinity 6% (w/v) as optimum for maximum specific growth rate, 0.578 h−1 and thrombinase activity, 8.34 FU mL−1.

► Marine actinomycetes found to be effective for thrombinase production.
► Low intensity ultrasonication increase the cell biomass, enzyme activity and even specific growth rate.
► Increase in salinity promotes better salt tolerance of isolate, cell growth and enzyme activity.
► Optimization by central composite design proved as significant for obtaining optimum conditions for bioprocess.