Lipases form one of the most important groups of biocatalysts used in biotechnology. We studied the
lipase from the bacterium Cohnella sp. A01 due to the versatility of thermophilic lipases in industry. In
this study lipase 3646 gene from the thermophilic bacterium Cohnella sp. A01 was expressed in
Escherichia coli and the enzyme was purified by a two-steps anion exchange chromatography. The purified lipase appeared to have a molecular weight of approximately 29.5 kDa on SDS–PAGE. The values of
max, calculated by the Michaelis–Menten equation, were 1077 lM and 61.94 U/mg, respectively.
The kinetic characterization of the purified enzyme exhibited maximum activity at 70 C and pH 8.5.
Activities at 50, 55 and 60 C for 120 min were measured 58%, 47% and 41%, respectively. The enzyme
was also highly stable at the pH range of 8.5–10.0 for 180 min. The effect of EDTA indicated that the
enzyme is not a metalloenzyme. The stability of lipase 3646 in the presence of organic solvents, detergents, metal ions and inhibitors suggested that this lipase could be exploited in certain industries such
as detergent and leather. Lipase 3646 was determined structurally to be 37.5% a-helix, 12.8% b-sheet,
22.7% b-turn and 27% random coil.