Bacillus amyloliquefaciens Alkaline Protease: Potential Applications and Stabilization

Bacillus amyloliquefaciens alkaline protease (AL-PR) was partially purified and a 2.55 purification fold was achieved at 60% ammonium sulfate. The partially purified AL-PR was then characterized with respect to its presented activities and stabilities at variable pHs and temperatures. The partially purified AL-PR was slightly inhibited by PMSF(serine proteases inhibitor) and was completely inhibited by both EDTA (a general metalloprotease inhibitor) and 1,10 phenanthroline ( a zinc metalloinhibitor), These results indicated that the enzyme might be a Zn metalloprotease. The partially purified AL-PR offered antimicrobial activity versus Bacillus cereus, Pseudomonas aeruginosa, and Candida albicans. It also offered antioxidant activity against DPPH with an IC50 of 0.59 mg/ml. Moreover, the partially purified AL-PR was proven to be safe to normal skin cells (BJ1) and it also promoted wound healing. Thus, the partially purified AL-PR has potential for wound healing applications. In order to further promote its application, it was stabilized via conjugation with variable oxidized polysaccharides. Conjugation with oxidized DEAE dextran and carboxymethyl cellulose elevated the thermal stability of the partially purified AL-PR. Nonetheless, CMC imparted a bigger stabilizing effect as it caused the AL-PR t1/2 and D-values (at 60 degrees C) to be 5.97 fold raised.