Optimization of Fermentation Conditions of P.variabile JN-A525 and Substrate Specificity of Urethanase

Abstract:

The fermentation process for P.variabile JN-A525 was optimized by single factor experiment and orthogonal tests.The results showed that the medium was composed of glucose 20 g/L,beef extract 10 g/L,KH2 PO4 5 g/L,NaCl 1 g/L and KCl 5 g/L.The optimum fermentation conditions was 32 ℃,inoculum volume 3%,the optimum amount in flask 70/250 mL and the rotation speed of 100 r/min.Under these optimal conditions,the highest urethanase activity is 3.47 fold more than that of previous cinditions.After sonication methods,sodium-sulfate salting-out and superdex G-75 gel filtration chromatography,the urethanase from Penicillium variabile JN-A525 is further determined substrate specificity.Under simulated conditions,the urethanase has a relatively strong catalytic activity to urea and EC.Meanwhile,urethanase cannot catalyze the decomposition of amino acids and esters.