Activity of Candida rugosa lipase for synthesis of hexyl octoate under high hydrostatic pressure and the mechanism of this reaction

Candida rugosa lipase (CRL) in organic solvent was treated under high hydrostatic pressure. The lipase was activated at pressure below 300 MPa while deactivated at pressure over 400 MPa. Especially, the esterification activity of CRL was enhanced by 90% at 300 MPa but reduced to 85% at 500 MPa. Consistent with the activation of CRL under 300 MPa, the ester yield and initial reaction rate was also enhanced significantly at this pressure incubated for 45 min. In addition, the activation volume at moderate pressure (0.1–300 MPa) was −6.46 ± 1.2 mL/mol at 40 °C. The effects of substrate molar ratio and concentration suggested that the excess of the acid and alcohol both inhibited the lipase. The study of kinetics indicated that the mechanism of CRL-catalyzed hexyl octoate in isooctane followed a Ping-Pong Bi-Bi mechanism with dead-end inhibition by both substrates. © 2017