Physical and covalent immobilization of lipase: different behaviour in the alkyl ester hydrolysis reaction

Immobilization of Lipase from Rhizomucor miehei on Silicalite-1 self-bonded pellets prepared by F and OH media is here repored. In order to obtain supports having different physical-chemical surface properties, the Silicalite-1 type materials have been prepared using two different mineralizing agent. The physical adsorption of the enzyme shows that the support, prepared in F- media, allows to attach the highest protein amount (280 mg/g) with respect to those ones obtained in alkaline system (200 mg/g) due to different electrostatic involved binding forces between the enzyme and the support surface. The catalytic activity of the immobilized enzyme was evaluated towards the alkyl ester hydrolysis reaction showing that the immobilized lipase on the support obtained in fluoride media could be in its close conformation. While, on the supports prepared in OH-media, the acid-base interactions between the Si-OH groups present on the support surface and the enzyme allow to obtain the activated lipase in the lid opening conformation [1]. Moreover, the activity of the same enzyme physically immobilized on the Silicalite-1 type suppo was compared with the performance of the lipase covalently attached on the Sepiolite/AlPO4 fuctionalized support [2]. The stability, the leaching and the total productivity of the enzyme unlikely immobilized (physically or covalently) has been measured and compare