1Bioprocess and Downstream processing Laboratory, Department of Biotechnology, Sri Venkateswara College of Engineering Sriperumbudur, Tamilnadu, India-602105.
2Department of Chemical and Process Engineering, University of Canterbury Private Bag 4800, Christchurch, New Zealand-8140.
*Previous affiliation: Bioprocess and Downstream processing Laboratory Department of Biotechnology, Sri Venkateswara College of Engineering, Sriperumbudur, Tamilnadu, India-602105
Streptokinase is an extracellular metallo-enzyme produced by beta-hemolytic streptococcus and is used as an effective and cheap clot-dissolving medication in myocardial infarction and pulmonary embolism. Recombinant Streptokinase produced in E.coli is a non-glycosylated polypeptide chain containing 414 amino acids and having a molecular weight of 47 kDa. In our present work salt inducible engineered E.coli GJ1158 strain with pSSY4 plasmid containing the streptokinase encoding gene was used for different fermentation studies. Addition of sodium chloride increased the osmolarity of the medium and also triggered the induction process. Initial studies were carried out in shake flash, which was then scaled up in the reactor modes such as Batch, Fed Batch and Total retention Culture. The experiments were done in Glucose Yeast Extract medium. In salt inducible system, the high cell density cultivation was attempted and the concentrated feed increased the osmotic pressure. Considering the toxicity of streptokinase to the host for achieving good production rate, a tight regulation of promoter was achieved by using Total Cell Retention Culture. It also increased the cell density and productivity. The results concluded that the difficulties in Batch and Fed batch cultivation of E.coli GJ1158 for the production of recombinant streptokinase was overcome by Total cell Retention Culture.
Streptokinase, total cell retention, E.coli, salt induction, high cell, density
