Covalent immobilization of lipase from Candida rugosa onto poly(acrylonitrile-co-2-hydroxyethyl methacrylate) electrospun fibrous membranes for potential bioreactor application.

A simple way of fabricating enzymatic membrane reactor with high enzyme loading and activity retention from the conjugation between nanofibrous membrane and lipase was devised. Poly(acrylonitrile-co-2-hydroxyethyl methacrylate) (PANCHEMA) was electrospun into fibrous membrane and used as support for enzyme immobilization. The hydroxyl groups on the fibrous membrane surface were activated with epichlorohydrin, cyanuric chloride or p-benzoquinone, respectively. Lipase from Candida rugosa was covalently immobilized on these fibrous membranes. The resulted bioactive fibrous membranes were examined in catalytic efficiency and activity for hydrolysis. The observed enzyme loading on the fibrous membrane with fiber diameter of 80-150 nm was up to 1.6% (wt/wt), which was as thrice as that on the fibrous membrane with fiber diameter of 800-1,000 nm. Activity retention for the immobilized lipase varied between 32.5% and 40.6% with the activation methods of hydroxyl groups. Stabilities of the immobilized lipase were obviously improved. In addition, continuous hydrolysis was carried out with an enzyme-immobilized fibrous membrane bioreactor and a steady hydrolysis conversion (3.6%) was obtained at a 0.23 mL/min flow rate under optimum condition.