Screening Of A Thermophilic Proteinase Producing Strain Bacillus Sp. Dpe7 , Condition For Enzyme Producing And Research On The Property Of Enzyme

A strain producing a thermophilic protcinase, named Bacillus sp.DPE?, was isolated from samples of hot spring. The optimum medium for the strain's growth is: Glucose 10 g, Peptone 2g, Yeast Extract 2g, NaCl 3g, H:O 1000ml, PH=8.0. The optimum culture temperature is 65X2 and the optimal stirring speed is ISOrpm. The optimum medium for producing proteinase is : (NH^SO^ lgf Yeast Extract Ig, Glucose Ig, NaCI Ig, MgSO4 O.Sg, MnCl2 O.OSg, Casein O.lg, CaCl2 2g, H2O 1000ml, pH=9.0 . The enzyme activity of supernatant is 23.4U/ml(determined at 60X2)after Bacillus sp. DPEywas grown in the medium for producing proteinase for 24h. The thermophilic proteinase from Bacillus sp. DPE? is a extracellular protcinase and the extracellular proteinase activity is about 90% of the total enzyme activity. The optimum reaction PH of the proteinase is 9.0 and its optimum reaction temperature is 85X2. About 60% of the original activity remained after incubation at 80X2 for 2 hour and its half lifetime is 20min at 90X2. The proteinase is fairly stable from pH 6.0 to 11.0 at 60X2and from pH 6.0 to 10.0 at 80X2. Ca2+ and organic solvent can enhance enzyme thermostalility. Based on the above, the thermophilic proteinase from Bacillus sp.DPE7 shows relatively high stability and function well in a relatively wide pH range. The strain is promising in producing thermophilic proteinase...