Isolation, Expression and Characterization of the Thermophilic Recombinant Esterase from Geobacillus...

Esterases are widely used in the food industry. Here, a new thermophilic bacterium, Geobacillus thermodenitrificans PS01, was isolated and the esterase-encoding gene est1 was cloned, sequenced, and recombinant expressed in Escherichia coli Tuner (DE3). The highest activity of recombinant Est1 was detected at pH 8.0, and 40 °C and the extreme stability was observed at pH 6-9 over 30 days at 4 °C. In particular, Est1 can hydrolyze short- to medium-chain (C2-C10) triglycerides and p-nitrophenyl esters (C2-C12) and was not inhibited by most metal ions. Kinetic parameters of p-nitrophenyl butyrate hydrolysis under optimal conditions were determined: K_m, 22.76 μM; k_cat, 10,415 s^-1; and k_cat/K_m, 457.53 μM^-1 s^-1. The outstanding specification of Est1 indicates its potential for use in industrial applications.