Gene cloning and characterization of a novel thermophilic esterase from Fervidobacterium nodosum Rt17-B1

A bioinformatic screening of the genome of the thermophilic bacterium Fervidobacterium nodosum Rt17-B1 for esterhydrolyzing enzymes revealed a putative bacterial esterase (FNE) encoded by Fond_1301 with typical GDSL family motifs. To confirm its putative esterase function, the FNE gene was cloned, functionally expressed in Escherichia coli, and purified to homogeneity. Recombinant FNE exhibited the highest esterase activity of 14,000 U/mg with p-nitrophenyl acetate (pNPC2) as substrate. The catalytic efficiency (kcat/Km) toward p-nitrophenyl acetate (C2 )w as approximately 120-fold higher than toward p-nitrophenyl butyrate (C4). No significant esterase activity was observed