title: Estimation of bound and free fractions of lignocellulose-degrading enzymes of wood-rotting fungi Pleurotus ostreatus, Trametes versicolor and Piptoporus betulinus.
abstract: Liquid cultures with cellulose and solid state fermentation cultures on wheat straw of the white-rot fungi Pleurotus ostreatus and Trametes versicolor and the brown-rot fungus Piptoporus betulinus were assayed for the free and solid fraction-bound activity of lignocellulose-degrading enzymes. The majority of the ligninolytic enzymes laccase and Mn peroxidase was detected in the free fraction of P. ostreatus and T. versicolor. The endocleaving enzymes endo-1,4-beta-glucanase, endo-1,4-beta-mannanase and endo-1,4-beta-xylanase were detected almost exclusively in the free fraction, while significant amounts of 1,4-beta-glucosidase, cellobiohydrolase, 1,4-beta-xylosidase and 1,4-beta-mannosidase were present in the bound fraction depending on the mode of cultivation and the species. The bound enzymes accounted for 66% of the total activity in P. ostreatus straw cultures, 35% in T. versicolor and only 8% in P. betulinus. The enzymes also showed significant differences in freeze-drying stability. Hydrolases in general showed high stability, whereas laccase and Mn peroxidase of P. ostreatus were the least stable.
authors.affiliation: Laboratory of Biochemistry of Wood-Rotting Fungi, Institute of Microbiology ASCR, Vídenská 1083, 14220 Praha 4, Czech Republic.
authors.forename: Vendula
authors.initials: V
authors.lastname: Valásková
authors.forename: Petr
authors.initials: P
authors.lastname: Baldrian
mesh_terms: D044602:Cellulases / Q000032:analysis; D002482:Cellulose / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D004795:Enzyme Stability; D004798:Enzymes / Q000032:analysis*; D005612:Freeze Drying; D005656:Fungal Proteins / Q000032:analysis; D006026:Glycoside Hydrolases / Q000032:analysis; D042845:Laccase / Q000032:analysis; D008031:Lignin / Q000378:metabolism*; D010544:Peroxidases / Q000032:analysis; D020076:Pleurotus / Q000201:enzymology*; D020072:Polyporales / Q000201:enzymology*
chemical_list: D003470:Culture Media; D004798:Enzymes; D005656:Fungal Proteins; C036909:lignocellulose; D002482:Cellulose; D008031:Lignin; D042845:Laccase; D010544:Peroxidases; C051129:manganese peroxidase; D044602:Cellulases; D006026:Glycoside Hydrolases; C023305:hemicellulase