Study on Alkaline Protease from Bacillus licheniformis A

The alkaline protease produced by the fermentation of Bacillus licheniformis A,a strain isolated from the hydrolysate of 60Co-irradiated Acaudina leucoprocta was salted out from the fermentation supernatant with ammonium sulfate.After DEAE-Sepharose ion exchange chromatographic separation and subsequent Sephadex G-75 gel permeation chromatographic purification,an alkaline protease yield of 5.8% was achieved.The alkaline protease was determined by SDS-PAGE to have a molecular weight of 35 kD.The optimal reaction temperature and pH of the enzyme were 50 ℃ and 11,respectively.The enzyme had perfect thermostability and a certain level of resistance to oxidation.