Production of wood-decay enzymes, mass loss and lignin solubilization in wood by tropical Xylariaceae

Abstract

Tropical xylariaceous taxa in the genera Biscognauxia, Hypoxylon and Xylaria were evaluated for their ability to produce wood-decay enzymes and effect mass loss and lignin solubilization in angiosperm and gymnosperm wood. All xylariaceous taxa were capable of cellulose and xylan hydrolysis, but few produced enzymes involved in lignin breakdown. Xylariaceous fungi were incapable of causing mass loss in gymnosperm wood, but several caused significant mass loss in angiosperm wood during a six month in vitro exposure. Mass loss values obtained were low at approx. 20% of those obtained for basidiomycetes. Lignin was solubilized at similar rates to mass loss by Hypoxylon and Xylaria species, resulting in indices of lignin solubilization between 0.88 and 1.11, which were similar to those obtained for white-rot basidiomycetes and higher than those previously reported for any other xylariaceous fungi.