Two detergent stable alkaline serine-proteases from Bacillus mojavensis A21: Purification, characterization and potential application as a laundry detergent additive

Two detergent stable alkaline serine-proteases (BM1 and BM2) from Bacillus mojavensis A21 were purified. The molecular weights of BM1 and BM2 enzymes determined by SDS–PAGE were approximately 29,000 Da and 15,500 Da, respectively. The optimum pH values of BM1 and BM2 proteases were shown to be 8.0–10.0 and 10.0, respectively. Both enzymes exhibited maximal activity at 60 °C, using casein as a substrate.The N-terminal amino acid sequences of BM1 and BM2 proteases were AQSVPYGISQIKA and AIPDQAATTLL, respectively.Both proteases showed high stability towards non-ionic surfactants. The enzymes were found to be relatively stable towards oxidizing agents. In addition, both enzymes showed excellent stability and compatibility with a wide range of commercial liquid and solid detergents. These properties and the high activity in high alkaline pH make these proteases an ideal choice for application in detergent formulations.