Degradation of wheat straw and oak sawdust by Ganoderma applanatum

Ganoderma applanatum is a widely-distributed wood decaying species whose ligninolytic enzyme system has not been sufficiently studied. The aims of the study were to profile its Mn-oxidizing peroxidases and laccases and defining of wheat straw and oak sawdust delignification extents depending on cultivation type. Activities of these enzymes were higher in submerged than in solid-state cultivation. Oak sawdust induced the highest activities of Mn-dependent (5545.5 U L-1) and Mn-independent peroxidases (5810.0 U L-1), and wheat straw stimulated laccase activity (11007.0 U L-1). The isoelectric focusing profiles of enzymes and extent of lignocellulose degradation were affected by plant residue as well as type and period of cultivation. Submerged cultivation induced the synthesis of a higher number of enzyme isoforms and the maximum levels of lignin, hemicellulose and cellulose degradation (40.9%, 32.7% and 27.4%) were reached during this oak sawdust fermentation. However, selectivity in fiber mineralisations was the highest during solid-state fermentation of wheat straw, which is important for possible application in various biotechnological processes that require accessible cellulose, such as production of more digestible feed, paper pulp and bioethanol. (C) 2016 Elsevier Ltd. All rights reserved.