Enzymatic activities and degradation properties of fungi isolated from decayed Quercus variabilis

Abstract The objective of this study is to investigate the microorganisms responsible for the decay of Quercus variabilis . Fungi were isolated and identified from collected Q. variabilis samples, and their lignocellulose-degrading enzyme activities were assessed using carboxymethyl cellulose (CMC) sodium salt and 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) diammonium salt as substrates. The fungal isolates consisted of 48 species of Ascomycota, 11 species of Basidiomycota, and 4 species of Mucoromycota, totaling 63 species. Among these, 31 species exhibited both cellulase and laccase activities. The lignocellulose-degrading enzyme activities of eight Basidiomycota species, where both cellulase and laccase activities were detected, were monitored over time. Phlebia acerina demonstrated the highest cellulase and laccase activities, with 5.1 IU/mL and 19.8 U/L, respectively. The wood-decomposing ability of eight Basidiomycota was evaluated according to KS F 2213:2004. P. acerina and Emmia lacerata exhibited the highest Weight loss percentages for 60 days, at 8.8% and 8.4%, respectively, suggesting their involvement in the decay of Q. variabilis . These findings would be conducive to offering information on wood-decaying fungi that may help to reduce the economic loss resulting from the inability of Q. variabilis to be used in various ways due to fungal decay.