Enhanced Lignocellulolytic Enzyme Activities on Hardwood and Softwood during Interspecific Interactions of White- and Brown-Rot Fungi

Abstract

Wood decomposition is a sophisticated process where various biocatalysts act simultaneously and synergistically on biopolymers to efficiently break down plant cell walls. In nature, this process depends on the activities of the wood-inhabiting fungal communities that co-exist and interact during wood decay. Wood-decaying fungal species have traditionally been classified as white-rot and brown-rot fungi, which differ in their decay mechanism and enzyme repertoire. To mimic the species interaction during wood decomposition, we have cultivated the white-rot fungus, <i>Bjerkandera adusta</i>, and two brown-rot fungi, <i>Gloeophyllum sepiarium</i> and <i>Antrodia sinuosa</i>, in single and co-cultivations on softwood and hardwood. We compared their extracellular hydrolytic carbohydrate-active and oxidative lignin-degrading enzyme activities and production profiles. The interaction of white-rot and brown-rot species showed enhanced (hemi)cellulase activities on birch and spruce-supplemented cultivations. Based on the enzyme activity profiles, the combination of <i>B. adusta</i> and <i>G. sepiarium</i> facilitated birch wood degradation, whereas <i>B. adusta</i> and <i>A. sinuosa</i> is a promising combination for efficient degradation of spruce wood, showing synergy in β-glucosidase (BGL) and α-galactosidase (AGL) activity. Synergistic BGL and AGL activity was also detected on birch during the interaction of brown-rot species. Our findings indicate that fungal interaction on different woody substrates have an impact on both simultaneous and sequential biocatalytic activities.