Immobilization of Lipoxygenase, Catalase, and Lipase for a Reactor Design Targeting Linoleic Acid Hydroperoxidation

Hydroperoxy-9Z,11E-octadecadienoic acid (13-HPODE) can be obtained from safflower oil in an enzyme cascade utilizing lipase, lipoxygenase (LOX), and catalase for in situ oxygen generation. The application of immobilized enzymes may open a new path to a cost-efficient production of 13-HPODE, which is used for the synthesis of green note aroma hexanal. Ten immobilization supports are compared for immobilization of lipoxygenase-1 from Glycine max (LOX-1) and oxirane-based Immobead 150 P proves to be best with a maximum LOX-1 activity of 22 470 U g−¹. The immobilizate is successfully recycled in eight consecutive batches and maintains full activity over a period of 16 h using a 3D-printed column reactor. Catalase from Micrococcus lysodeikticus and LOX-1 are co-immobilized on Immobead 150 P allowing a constant production of 13-HPODE for up to six cycles with a maximum product conversion of 45% and a 13-regioselectivity of 83%. In this two-enzyme system with H₂O₂-dosage, foam generation is significantly reduced. Co-immobilization of LOX-1 and lipaseis possible; however, rapid lipase deactivation occurs. Therefore, a two-reactor approach with oil hydrolysis in the first reactor is proposed. Immobilized lipases from C. rugosa are suitable for safflower oil hydrolysis and maintain full activity over ten hydrolysis cycles. Practical applications: Linoleic acid hydroperoxide (13-HPODE) is the starting material for the synthesis of the green note aroma compound hexanal. The byproduct of the hydroperoxide splitting is ω-oxododecenoic acid, which is currently not employed industrially. The bifunctional oxodocecenoic acid is interesting as precursor for the synthesis of polymer building blocks. Simple one-step derivatization of the oxo-group can yield suitable C12 monomers such as dicarboxylic acids, ω-amino acids, or ω-hydroxy acids. Cost-efficiency is a key parameter to incorporate these new biobased building blocks for polymer applications. In this approach, immobilized enzymes are used for the synthesis of 13-HPODE starting from safflower oil with in situ oxygen generation to prevent excessive foam formation. A two-reactor concept is designed to circumvent hydroperoxide-induced lipase deactivation. Direct comparison of both batch and continuous process is performed and provides information for the implementation of the enzyme cascade and the design of an optimized reactor system.