New Insight into Old Bacillus Lipase: Solvent Stable Mesophilic Lipase Demonstrating Enzyme Activity towards Cold.

BACKGROUND

Bacillus lipases are grouped in subfamily 1.4, which are the smallest known lipases having a molecular mass of 19.6 kDa. Lipases active in a wide range of temperatures, specifically at low temperatures, have an advantage under low water conditions for industrial application.

METHODS

The lipase gene was cloned and expressed in Escherichia coli. The protein was purified and biochemically characterized in detail.

RESULTS

A lipase gene was cloned from a mesophilic Bacillus isolate. Sequence analysis revealed an open reading frame of 633 bp in length. The predicted molecular mass of protein was 22.6 kDa. The purified enzyme displayed optimal activity at 35 °C and pH 8.0. Interestingly, this mesophilic enzyme was also cold active showing retention of 75 and 55% relative enzyme activity at 20 and 10 °C, respectively. The purified lipase was stable in various organic solvents (50% v/v) and ionic liquids (5% v/v). The enzyme displayed maximum activity with paranitrophenyl laurate (C12). kcat/Km values for the purified lipase were calculated to be 5.8 ± 0.6 × 10(-6).

CONCLUSIONS

The lipase showed tolerance to various solvents as well as activity at low temperature. Therefore, this lipase might be of great potential to be employed in various industrial applications.