Biodegradation of lignocellulosic materials by soil fungi isolated under anaerobic conditions

Two strains of cellulose-fermenting fungi were isolated by plating soil samples on cellulose-containing agar medium and incubating under anaerobic conditions. Both strains used pentoses, hexoses, cellobiose, xylan, and lignin-derived compounds as microaerophilic and aerobic growth substrates. One isolate was identified as Trichocladium canadense and the other as a basidiomycete species. The production of lignocellulose-degrading enzymes by the two cultures grown on ball-milled filter paper slurry as the cellulose source and incubated anaerobically, microaerophilically, and in air, was investigated. Among the two strains, high levels of xylanase activity followed by CMCase activity were detected in the culture supernatants. β-glucosidase was present at lower levels than the CMCase. Avicelase was also detected but at much lower levels than the other activities. Highest activities for Trichocladium canadense (Strain Q10) were obtained when cultures were incubated under microaerophilic conditions; for the basidiomycete (strain H2), highest activities were obtained under air. Laccase activity was detected in the culture supernatants of both strains. Peroxidase activity was observed only in strain H2. Ethanol was the major non-gaseous fermentation product produced by both strains.