Catechol modification and covalent immobilization of catalase on titania submicrospheres

In this article, chemical modification with catecholic derivative in solution and subsequent immobilization of catalase (CAT) on titania submicrospheres (450–500 nm) were described. Catalase was first reacted with 3-(3,4-dihydroxyphenyl) propionic acid activated via 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) coupling chemistry. The above chemically modified CAT bearing catechol groups was then covalently bound to the surface of titania through the facile chelation reaction between the catechol groups and titania. The immobilized CAT retained 60% catalytic activity with a high loading capacity of 500 mg/g titania. Meanwhile, the immobilized CAT displayed enhanced operational stability, thermal stability and storage stability compared with native, modified CAT counterparts. In repeated batches of decomposition of hydrogen peroxide, after 10 and 19 cycles, the immobilized CAT maintained about 90% and 75% of its initial activity, respectively.