Enhanced production of thrombinase by Streptomyces venezuelae: Kinetic studies on growth and enzyme production of mutant strain

This investigation provides the enhanced production of thrombinase, a fibrinolytic enzyme using mutant Streptomyces venezuelae. Initially the mutagenesis of the marine isolate was done by UV and Ethyl methane sulfonate (EMS) and their mutational efficiencies were compared. The mutants were selected based on their high thrombinase activity and used for further studies. The mutant was found to be more halo and thermo tolerant comparing to wild. The effect of Dissolved oxygen level was also determined and the mutant offered the maximum specific growth rate as 0.2404 (h(-1)). The mutant showed high resistance to higher initial lactose concentration and the inhibition concentration was found to be 155.1 mg/mL. The effect of S-0/X-0 ratio on specific substrate consumption and production rate were also investigated. Both mutant and wild showed increase in specific substrate consumption and production rate at higher S-0/X-0 ratio but the mutant showed better values than the wild strain. (C) 2012 Elsevier Ltd. All rights reserved.