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

1Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040 Madrid, Spain; 2Instituto de Recursos Naturales y Agrobiología, CSIC, Reina Mercedes 10, PO Box 1052, E-41080, Seville, Spain; 3Instituto de Catálisis, CSIC, Cantoblanco, E-28049 Madrid, Spain.

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 Km app and a kcat 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.

This study has been supported by ENCE, the EU-Contract QLK5-99-1357, and the Spanish projects BIO2003-00621 and AGL2002-00393. AG acknowledges a ‘Ramón y Cajal’ contract of the Spanish MCYT.

Peer reviewed