RESUMO
The optimization on liquid fermentation and purification of the fibrinolytic enzyme from Stenotrophomonas maltophilia(DR-929) was investigated.The results showed the best fermentation are amidulin 2.0%,soya flour 1.0%,yeast extract 0.5%,NaCl 1.0%,CaCl2 0.02%,MgSO4 0.05%,inoculum of 36 hours,fermental time 4d,initial pH 8.0 or 9.0,temperature 25℃,volume of media 30ml,volume of inoculum 5% or 6%.The purification process includes the following steps: removing cells by the centrifugation,25%~70% saturation ammonium sulfate precipitation,HIC with Phenyl FF(high sub),IEC with Q-Sepharose FF,gel filtration chromatography with Superdex 75.SDS-PAGE electrophoresis was used to examine the purification effect,and the results indicated that homogeneous strap in SDS-PAGE and has a molecular weight around 28.3kDa.The purification factor and activity recovery of the fibrinolytic enzyme are 271.5 and 24.5%,respectively.