Immobilized lipoxygenase in a packed-bed column bioreactor: continuous oxygenation of linoleic acid

The continuous oxygenation of linoleic acid (LA) by immobilized lipoxygenas e (LOX) was studied. Enzymatic oxidation was carried out in a recirculating packed column reactor using immobilized LOX as the stationary phase and LA as the substrate. The column, when packed with LOX immobilized in either a calcium alginate set-gel matrix or a phyllosilicate sol-gel matrix, is equ ivalent to five continuous stirred tank reactors (CSTRs), The reactor casca de was calculated from the residence-time distribution for the reactor. Bas ed on mass-balance calculations, a set of mathematical equations for predic ting the concentration of oxygenated product generated in each CSTR was cal culated. Product formation in the packed column reactor was simulated and r esults calculated with the model were compared with the experimental result s, The data indicated that product yield (hydroperoxyoctadecadienoic acid, HPOD) increased asymptotically with reaction time. Experimentally, when the bioreactor was packed with calcium alginate sol-gel-immobilized LOX, an in itial linear increase in HPOD production with time was observed, but reache d a steady state. For the bioreactor packed with phyllosilicate sol-gel-imm obilized LOX, initial HPOD production increased more rapidly but reached a lower steady-state concentration, From these data, a simple computer simula tion model was developed to determine the process kinetics of this reactor design.