Noby_2018_Int.J.Biol.Macromol_120_1247

Esterases and lipases from extremophiles have attracted great attention due to their unique characteristics and wide applications. In the present study, an open reading frame (ORF) encoding a novel cold active esterase (EstN7) from Bacillus cohnii strain N1 was cloned and expressed in Escherichia coli. The full-length esterase gene encoding a protein of 320 amino acids with estimated molecular weight of 37.0 kDa. Amino acid sequence analysis revealed that the EstN7 belongs to family IV lipases with a characteristic penta-peptide motif (GXSXG), the catalytic triad Ser, Asp, His and the conserved HGGG motif of the family IV. The recombinant enzyme was purified to apparent homogeneity using nickel-affinity chromatography with a purification fold of 5 and recovery 94.5%. The specific activity of the purified enzyme was 336.89 U/mg. The recombinant EstN7 showed optimal activity at 5 degreesC moreover, EstN7 displayed full robust stability in the presence of wide range of organic solvents. The purified enzyme had K(m) and V(max) of 45 +/- 0.019 microM and 1113 micromol min(-1) mg(-1), respectively on p-NP-acetate. These promising characteristics of the recombinant EstN7 would underpin its possible usage with high potential in the synthesis of fragile compounds in pharmaceutical industries.