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The sterol esterase from the ascomycete Ophiostoma piceae was immobilized on novel polyacrylate-based epoxy-activated carriers (Dilbeads TM). Six supports with particle sizes between 120-165 m were prepared varying the composition of monomers, crosslinkers and porogens. Their surface areas and porosities were determined by N 2 adsorption and mercury intrusion porosimetry. The pore volumes ranged from 0.63 to 1.32 cm 3 /g, but only Dilbeads TM RS and NK had narrow pore size distributions (with maxima at 33.5 and 67.0 nm, respectively). The distribution of the enzyme in the support was studied by fluorescence confocal microscopy. The immobilized esterase on Dilbeads TM TA showed a significant pH and thermal stability and was assayed in the continuous hydrolysis of cholesteryl esters-present in the pulp industry process waters- .

A sterol esterase purified from cultures of the sapstain fungus Ophiostoma piceae was able to hydrolyse sterol esters and glycerides. The kinetics of sterol esters and triglyceride hydrolysis by this new esterase, estimated using a pH-stat, showed a K m app and a k cat app in the range of 0.9-1.1 mM and 70-300 s -1 , respectively. Its ability to hydrolyse both pure sterol esters and natural mixtures of saponifiable lipids from eucalypt wood was compared with those of commercial sterol esterases from other microbial sources. Its specific activity on sterol esters was higher than that found with all the commercial esterases assayed, and the highest hydrolysis of eucalypt sterol esters was also attained using the O. piceae esterase. This sterol esterase could be of biotechnological interest for the hydrolysis of sterol esters that form pitch deposits in paper pulp manufacturing.