Enhanced fibrinolytic protease production by Serratia marcescens RSPB11 through Plackett-Burman and response surface methodological approaches

Abstract

A well characterized alkaline metalloprotease enzyme called serralysin with fibrinolytic activity has been reported in the newly isolated Serratia marcescens RSPB11. In view of its potential application in thrombolytic therapy this study has been made for understanding the nutritional parameters requirement needed for production. Therefore, medium components required for the production of serralysin were optimized using a two step statistical approach. Fermentation variables were selected in accordance with the Plackett-Burman design and were further optimized via response surface methodological approach. A total of seven parameters viz., casein, dextrose, KH2PO4, MgSO4, NaCl, CaCl2 and inoculum have been considered for the optimization studies. The statistical model was constructed via central composite design (CCD) using five screened variables (casein, dextrose, KH2PO4, CaCl2 and inoculum size). An overall 51.8% increase in protease production was achieved in the optimized medium as compared with the unoptimized casein medium.With the application of statistical design methodology serralysin production increased significantly with optimized casein medium (23910 U/ml) when compared to yeast extract-peptone medium (5363 U/ml).