Hydrolysis of sterol esters by an esterase from Ophiostoma piceae: application to pitch control in pulping of Eucalyptus globulus wood

摘要

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 sterolesterase could be of biotechnological interest for the hydrolysis of sterol esters that form pitch deposits in paper pulp manufacturing.