Kinetic study of lipase catalyzed transesterification of jatropha oil in circulated batch packed bed reactor

• We studied various effects of transesterification by Lipozyme® IM in CBPBR.
• We investigated the stability of Lipozyme® IM during transesterification in CBPBR.
• We studied external mass transfer and internal diffusivity of Lipozyme® IM in CBPBR.
• We developed and validated kinetic model for transesterification by Lipozyme® IM.

In this study the transesterification of Jatropha curcas oil was performed in circulated batch packed bed reactor (CBPBR) with down-flow. Lipozyme® IM, an immobilized lipase from Rhizomucor miehei was used as biocatalyst. The effects of linear velocities, solvent systems and the lipase stability were examined to deduce the enzyme kinetics study. Experimental results showed that the highest methyl ester yield was gained from the solvent-free system using three step addition of methanol at 6.1 cm/min linear velocity. The immobilized lipase showed stability in CBPBR by maintaining 70% of its relative activity up to 10 cycles. The effects of external mass transfer and internal diffusivity on enzyme kinetics in CBPBR were also investigated. It was proven that the reaction in CBPBR was not significantly affected by external mass transfer and internal diffusion. A kinetic model was proposed considering the steps in mechanism, based on ping–pong bi bi with reverse inhibition by methanol. The model was fitted with enzyme kinetic data from the experiment and good correlations were achieved.