A novel metal-tolerant, solvent and surfactant stable protease from a new strain of Bacillus megaterium

This study reported the discovery of a novel protease from a new strain of Bacillus megaterium isolated from marine sediment in the Gulf of Thailand. Maximum protease production was achieved after 15 h at 30 °C and pH 5.0, 250 rpm. The enzyme was 48.92-fold purified to homogeneity using acetone precipitation and Hi-Trap phenyl FF column chromatography. It possesses a relative molecular mass of 60 kDa on SDS-PAGE. The enzyme was highly active over a broad range of pH (pH 3.0-12.0) and temperature (10-80 °C), and displayed the optimal activity at pH 10.0 and 50 °C. It was stable between 60 and 80 °C for 168 h, showing remarkable stability towards a wide range of pHs and hydrophobic solvents. Metal ions and inhibitors as well as detergents and bleaching agents do not significantly affect the enzyme activity. These promising properties make this enzyme a candidate biocatalyst for future use in harsh industrial processes.