The application of a halotolerant metalloprotease from marine bacterium Vibrio sp. LA-05 in liquid detergent formulations

Abstract

The application of a halotolerant metalloprotease from marine bacterium Vibrio sp. LA-05 in liquid detergent formulations was investigated in detail. The washing simulation experiment revealed that blood stains were successfully removed from cotton cloths by washing them with three commercial liquid detergents (Liby, Bluemoon and Walch) supplemented with the crude protease at 15–45 °C for 30 min. However, macroscopic residues of stains were remained on the cloths treated with tap water, liquid detergent alone and liquid detergent supplemented with the commercial protease subtilisin A. The analyses of microstructure, chemical elements and tensile properties showed that the washing treatments with crude protease as a bio-additive almost did not affect the texture, elemental composition or tensile properties of cloths. Sheep blood agar plate and SDS-PAGE analyses indicated that its hydrolysis activity to blood proteins was not significantly influenced even in the presence of liquid detergents. The hydrolysis mechanism was further studied and results demonstrated that this protease could specifically hydrolyzed six proteins in Sheep Red Blood Cells (SRBCs) and four proteins in sheep plasma. These findings suggest that this crude halotolerant metalloprotease as a bio-additive may have considerable potentials in the application of liquid detergent formulations.