Abstract:
Bacillus mutant UUNN-1 can produce high amount of alkaline protease in 5 liter batch fomenter. Culture medium contains KH[subscript 2]PO[subscript 4] 0.1%(w/v), MgSO[subscript 4].7H[subscript 2]O 0.05%(w/v), CaCl[subscript 2].2H[subscript 2]O 0.001%(w/v) and extraction of soy been meal and sunflower seed meal with nitrogen content 0.4%(w/v) in total volume of 3.5 liter. The optimal conditions for culturing were as follows : inoculum size at 1%(v/v) of the culture volume, aeration rate at I vvm, agitation speed of 250 rpm, temperature at 37 degree Celsius and initial pH at 7.0. This strain can produce the highest amount of alkaline protease 1,579 units/gram cell dry weight at 36 hours. The protease was partially purified by ammonium sulfate precipitation at 40-60%(w/v), DEAE-cellulose and Sephadex G-100 column chromatography. The purification was 165 fold with specific activity of 1,688 units/mg protein. The molecular weight that was estimated with Sephadex G-100 chromatography is 27,000 Dalton. The enzyme has protease activity at temperature 30-65 degree Celsius, pH 8.5-10.5 and optimum temperature at 45 degree Celsius, pH 10.5. The partially purified enzyme showed K[subscript m] of 0.083% by weight for casein and V[subscript max] of 0.0087 OD/min for casein and protease activity was inhibited by phenylmethylsulfonyl fluoride (PMSF).