| Popis: |
Kinetics of lipase-catalyzed esterification of hexanoic acid and ethyl alcohol using the solvent-free system, surface coated lipase from Candida rugosa, had been studied. The effect of various parameters such as reaction time, reaction temperature, reaction kinetics, water removal and feasibility of solvent-free system had been focused. Candida Rugosa lipase was more effective than other lipases when ethyl hexanoate was synthesized in n-hexane. The highest esterification yield after 72 h (93 %) was achieved at a pH of 5.2 and the esterification yield was reduced to 73% at pH 4.0. The values of the apparent kinetic parameters were computed as Vmax= 0.146 μmol/min/mg enzyme; KM, Acid = 0.296 M; KM, Alcohol = 0.1388 M; Ki, Acid = 0.40 M; and Ki, Alcohol = 0.309 M. The reaction rate could be described in terms of the Michaelis–Menten equation with a Ping-Pong Bi-Bi mechanism and competitive inhibition by both the substrates. |
