Solvent Free Lipase Catalysed Synthesis of Ethyl Laurate: Optimization and Kinetic Studies

The current research work represents solvent free enzymatic synthesis of fatty acid ethyl ester; ethyl laurate. Immobilized lipase Fermase CALB™10,000 was used for the synthesis of ethyl laurate from ethanol and lauric acid. The influence of process parameters such as catalyst loading, speed of agitation, mole ratio, molecular sieves and temperature were studied. Fermase CALB™10,000 offered a conversion of 92.46 % at 60 °C in 4 h at optimized condition. The experimental data was best fitted by the Random Bi-Bi model with inhibition of both the substrates i.e. lauric acid and ethanol. The following kinetic parameters were retrieved from the model: V_max = 1.243 × 10³ mmol/min/g enzyme; K_A = 0.1283 mmol; K_B = 8.51 mmol; K_iA = 5.098 mmol; and SSE = 0.0142. The activation energy for the enzymatic esterification was also determined and calculated to be 28.49 kJ/mol. A maximum conversion of 71 % was obtained after 5 successive reuse of Fermase CALB™10,000 lipase.