Selection and validation of enzymatic activities as functional markers in wood biotechnology and fungal ecology

The dead wood and forest soils are sources of diversity and under-explored fungal strains with biotechnological potential, which require to be studied. Numerous enzymatic tests have been proposed to investigate the functional potential of the soil microbial communities or to test the functional abilities of fungal strains. Nevertheless, the diversity of these functional markers and their relevance in environmental studies or biotechnological screening does still have not been demonstrated. In this work, we assessed ten different extracellular enzymatic activities involved in the wood decaying process including β-etherase that specifically cleaves the β-aryl ether linkages in the lignin polymer. For this purpose, a collection of 26 fungal strains, distributed within three ecological groups (white, brown and soft rot fungi), has been used. Among the ten potential functional markers, the combinatorial use of only six of them allowed separation between the group of white and soft rot fungi from the brown rot fungi. Moreover, our results suggest that extracellular β-etherase is a rare and dispensable activity among the wood decay fungi. Finally, we propose that this set of markers could be useful for the analysis of fungal communities in functional and environmental studies, and for the selection of strains with biotechnological interests.

► Ten enzymatic activities involved in the wood decaying process have been tested with 26 lignocellulolytic fungal strains.
► The β-etherase activity, that cleaves the β-aryl ether linkages, was looked up in the fungal collection.
► Our results suggest that extracellular β-etherase is a rare and dispensable activity among the wood decay fungi.
► The use of only six activities allowed separation between the group of white/soft rot fungi from the brown rot fungi.