A novel organic solvent-stable alkaline protease from organic solvent–tolerant Bacillus licheniformis YP1A

An organic solvent-stable alkaline protease producing bacterium was isolated from the crude oil contaminant soil and identified as Bacillus licheniformis. The enzyme retained more than 95% of its initial activity after pre-incubation at 40 °C for 1 h in the presence of 50% (v/v) organic solvents such as DMSO, DMF, and cyclohexane. The protease was active in a broad range of pH from 8.0 to 12.0 with the optimum pH 9.5. The optimum temperature for this protease activity was 60 °C, and the enzyme remained active after incubation at 50–60 °C for 1 h. This organic solvent-stable protease could be used as a biocatalyst for organic solvent-based enzymatic synthesis.