Abstract
Novozyme 435, which is a commercial immobilized lipase B from Candida antarctica (CALB), has been proven to be inadequate for the kinetic resolution of rac-indanyl acetate. As it has been previously described that different immobilization protocols may greatly alter lipase features, in this work, CALB was covalently immobilized on epoxy Immobead-350 (IB-350) and on glyoxyl-agarose to ascertain if better kinetic resolution would result. Afterwards, all CALB biocatalysts were utilized in the hydrolytic resolution of rac-indanyl acetate and rac-(chloromethyl)-2-(o-methoxyphenoxy) ethyl acetate. After optimization of the immobilization protocol on IB-350, its loading capacity was 150 mg protein/g dried support. Furthermore, the CALB-IB-350 thermal and solvent stabilities were higher than that of the soluble enzyme (e.g., by a 14-fold factor at pH 5-70 degrees C and by a 11-fold factor in dioxane 30%-65 degrees C) and that of the glyoxyl-agarose-CALB (e.g., by a 12-fold factor at pH 10-50 degrees C and by a 21-fold factor in dioxane 30%-65 degrees C). The CALB-IB-350 preparation (with 98% immobilization yield and activity versus p-nitrophenyl butyrate of 6.26 +/- 0.2 U/g) was used in the hydrolysis of rac-indanyl acetate using a biocatalyst/substrate ratio of 2:1 and a pH value of 7.0 at 30 degrees C for 24 h. The conversion obtained was 48% and the enantiomeric excess of the product (e.e.(p)) was 97%. These values were much higher than the ones obtained with Novozyme 435, 13% and 26% of conversion and e.e.p, respectively. (C) 2018 American Institute of Chemical Engineers