Filamentous fungi can degrade aspen steryl esters and waxes

Along with triglycerides, steryl esters and waxes are among the major contributors to pitch problems during pulping. Aspen wood has a high composition of these compounds, as a result it causes severe pitch deposition when pulped. Fungal pretreatment of wood chips to remove pitch forming components has been proposed, but the commercial fungus, Cartapip™ does not degrade steryl esters and waxes efficiently. Therefore, we screened twenty-five wood-inhabiting fungi for their ability to use aspen steryl esters and waxes as a carbon source. Ten fungi were effective in degrading the steryl esters and waxes which they accomplished by hydrolyzing these esters into their fatty acid and sterol moieties.