This work reports bioconversion of unsaturated free fatty acids present in soapstock, inherent waste of edible oil manufacture, to the epoxidized fatty acids using Candida rugose lipase in a micro-reactor. Activation energy of the epoxidation reaction was found to be 32.27kJmol(-1) while the enzyme deactivation was observed at higher temperature than 35 degrees C with an activation energy of 91.18kJmol(-1). The low hydrodynamic retention time in the micro-reactor provides a proper condition to measure of initial rates of the enzymatic reaction. The kinetics study was performed at ten different molar ratios of H2O2/C=C, and constants of the Ping-Pong bi bi model were estimated as follows: the maximum specific enzyme activity (V-max) of 1.453x10(5)mMmin(-1)g(enzyme)(-1), dissociation constant for enzyme-FFA complex (K-A) of 58.83mM g(enzyme)(-1), Michaelis constant for FFAs (K-mA) of 1.382x10(3)mM g(enzyme)(-1), Michaelis constant for hydrogen peroxide (K-mB) of 3.279x10(6)mM g(enzyme)(-1), and the deactivation constant due to hydrogen peroxide (K-IB) of 59.25mMg(enzyme)(-1). The cross-linked enzyme aggregate technology provided a simple method to produce the robust biocatalyst for this bioconversion where more than 89% of original activity was maintained after 9 cycles in the micro-reactor. [GRAPHICS] .