This research investigates the epoxidation of unsaturated free fatty acids obtained from soap stock after treating through the degumming process. The Fe3O4-loaded whole-cells of Candida catenulata were used as the biocatalyst for the synthesis of epoxy fatty acids within serpentine and spiral microfluidic reactors under an electrically induced magnetic field (IMF). The magnetic properties of the biocatalyst particles were applied to improve the mixing behaviors of the immiscible reactants within the reactors. The syringe of the spiral microfluidic reactor and magnetic biocatalyst motions provide advantages to obtain a high epoxidation yield at low retention time. Also, the biocatalyst frequency under the IMF system showed a significant role on the epoxidation of fatty acids in this system. Therefore, optimization of the epoxidation reaction was evaluated by analyzing the effects of the reactant flow rate (X1), the biocatalyst loading (X2), and the frequency of the induced magnetic field (X3) in the microfluidic reactor. The optimal conditions were determined at X1 = 0.229 ml min− 1, X2 = 100 wv− 1, and X3 = 2.5 Hz with an epoxidation yield of 47.67% after 1.53 min as the hydrodynamic retention time. The cascading of microreactors for achieving high conversion efficiency was also studied and the results showed a cascade consisting of six spiral reactors gained an epoxy fatty acid conversion of about 90.17%. The epoxidation reaction at the continuous operation and 80.66% of the initial conversion yield was saved after 12 h.
Tohfegar et al. (2026) studied this question.