Effects of Nitrogen Supplements on Degradation of Aspen Wood Lignin and Carbohydrate Components by Phanerochaete chrysosporium

Abstract

A supplement of KH(2)PO(4), MgSO(4), CaCl(2), trace elements, and thiamine accelerated the initial rate of aspen wood decay by Phanerochaete chrysosporium but did not increase the extent of lignin degradation. Asparagine, casein hydrolysate, and urea supplements (1% added N) strongly inhibited lignin degradation and weight loss. The complex nitrogen sources peptone and yeast extract stimulated lignin degradation and weight loss. Albumen and NH(4)Cl had intermediate effects. Conversion of [C]lignin to CO(2) and water-soluble materials underestimated lignin degradation in the presence of the complex N sources. The highest ratio of lignin degradation to total weight loss and the largest increase in cellulase digestibility occurred during the decay of unsupplemented wood. Rotting of aspen wood by P. chrysosporium gives smaller digestibility increases than have been found with some other white-rot fungi.