Preparation of lipase cross-linked enzyme aggregates in octyl-modified mesocellular foams

Lipase r27RCL from Rhizopus chinensis was immobilized onto octyl-modified mesocellular foams (MCFs-C8) via two-step process of enzyme adsorption and cross-linking. Oxidized gum arabic was used as substitute for harmful glutaraldehyde to improve catalytic performance of immobilized enzyme for catalysis in non-aqueous phase. The parameters like aldehyde concentration, cross-linking time were optimized. Cross-linked enzyme aggregates (CLEAs) of lipase r27RCL prepared in MCFs-C8 by using oxidized gum arabic (GA-CLEAs@MCFs-C8) showed the highest esterification activity (145 μmol min^-1 mg^-1 protein) compared with lipase adsorbed onto MCFs-C8 (MCFs-C8-r27RCL) (98 μmol min^-1 mg^-1 protein), CLEAs of lipase in MCFs-C8 by glutaraldehyde (G-CLEAs@MCFs-C8) (88 μmol min^-1 mg^-1 protein) and immobilized lipase onto octyl/epoxy (1,1, v/v) modified MCFs (MCFs-octyl-epoxy-r27RCL) (35 μmol min^-1 mg^-1 protein). Moreover, GA-CLEAs@MCFs-C8 exhibited excellent thermal and mechanical stability, and could still maintain 69% of initial activity after 5 time cycles.