Immobilization of different protein fractions from Rhizomucor miehei lipase crude extract

The hydrolytic enzymes contained in a crude extract from Rhizomucor miehei (RML) were immobilized onto different supports. The catalytic behavior of the different enzyme derivatives in the resolution of esters of racemic 2-tetralol and structurally related secondary alcohols was investigated. We observed that, when the immobilization occurs by adsorption on highly hydrophobic solid surfaces, such as octyl-agarose or octadecyl-Sepabeads, only the lipase fraction (36 kDa) was immobilized and the resulting catalysts showed good lipasic activity and high enantioselectivity. By contrast, when immobilization was performed by ionic or covalent attachment, all proteins contained in the crude extract were immobilized and both activity and enantioselectivity were found to be much lower. The different enantioselectivity seems to be related to conformational changes of the lipase fraction (36 kDa) in the different immobilization approaches. (R)-2-Tetralol was obtained with high enantiomeric excess (89% at 50% of conversion, E = 51) by hydrolysis of the corresponding butyric acid ester using RML on octyl-agarose.