Wednesday, November 7, 2007

Comparison of Lipase-Catalyzed Esterification on Micro and Bench Scale

Jan W. Swarts, Petra Vossenberg, Marieke H. Meerman, Anja E.M. Janssen, and Remko M. Boom. Food and Bioprocess Engineering group, Wageningen University and Research Centre, Bomenweg 2, Wageningen, Netherlands

This research was focused on the possible kinetic differences between an esterification reaction on micro scale and on bench scale. Lipase type B from Candida antarctica was used to catalyze the esterification of propionic acid and 1-butanol in a water n-decane two phase system. In a micro channel (tens of micrometers in diameter) the phases with substrates and enzyme are combined and the reaction mixture remains in the chip for 45 seconds to 4 minutes. The reaction is stopped off chip. The bench scale experiments were conducted in 1.5 ml mixed tubes.

The reaction could be described by a Ping Pong Bi Bi mechanism with alcohol inhibition. No significant differences were found between the parameters found on micro scale and those found on bench scale. Mass limitation does not appear to play an important role in the reaction rate. Rather, the reaction is kinetically limited. As the kinetics on both scales are similar, parameters found on either one can be used in processing on the other scale.

Enzyme kinetic parameters can be determined on a micro scale, with very low consumption of reagents and catalyst, and then be applied to bench scale. This can reduce the cost of optimizing enzyme processes by downscaling.