title: Degradation of lignocellulose by Pleurotus ostreatus in the presence of copper, manganese, lead and zinc.
abstract: Pleurotus ostreatus produces the cellulolytic and hemicellulolytic enzymes endo-1,4-beta-glucanase, exo-1,4-beta-glucanase, 1,4-beta-glucosidase, endo-1,4-beta-xylanase, 1,4-beta-xylosidase, endo-1,4-beta-mannanase and 1,4-beta-mannosidase and ligninolytic enzymes Mn-peroxidase and laccase during growth on wheat straw in the presence and absence of Cu, Mn, Pb, and Zn. This is the first report concerning endo-1,4-beta-mannanase in P. ostreatus. Although the concentrations of trace metals in wheat straw ranged from units to tens of microg g(-1), only 3-6% (Fe, Pb) or 30-45% (Cu, Mn, Zn) of the total amount was extractable and available for the fungus. The substrate colonization rate was only decreased by high concentrations of Cu and Zn; the loss of dry mass differed among treatments in the initial phase of fungal growth, and at the end of the experiment (day 98) it was significantly lower in metal-containing treatments (63-66%) than in the control (70%). The cellulolytic and hemicellulolytic enzyme were prone to a metal effect except for the increase in endo-1,4-beta-glucanase and 1,4-beta-glucosidase in the presence of Zn. Laccase activity was increased by all tested metals, and unlike other white-rot fungi, Mn-peroxidase levels were low in the presence of manganese.
authors.affiliation: Laboratory of Biochemistry of Wood-Rotting Fungi, Institute of Microbiology ASCR, Vídenská 1083, 14220 Prague 4, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Baldrian
authors.forename: Vendula
authors.initials: V
authors.lastname: Valásková
authors.forename: Vera
authors.initials: V
authors.lastname: Merhautová
authors.forename: Jirí
authors.initials: J
authors.lastname: Gabriel
mesh_terms: D018533:Biomass; D002482:Cellulose / Q000378:metabolism*; D003067:Coenzymes / Q000378:metabolism / Q000494:pharmacology; D003300:Copper / Q000378:metabolism / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000032:analysis; D042845:Laccase / Q000032:analysis; D007854:Lead / Q000378:metabolism / Q000494:pharmacology; D008031:Lignin / Q000378:metabolism*; D008345:Manganese / Q000378:metabolism / Q000494:pharmacology; D010544:Peroxidases / Q000032:analysis; D020076:Pleurotus / Q000187:drug effects* / Q000378:metabolism*; D014131:Trace Elements / Q000378:metabolism* / Q000494:pharmacology*; D015032:Zinc / Q000378:metabolism / Q000494:pharmacology
chemical_list: D003067:Coenzymes; D014131:Trace Elements; C036909:lignocellulose; D007854:Lead; D008345:Manganese; D003300:Copper; D002482:Cellulose; D008031:Lignin; D006861:Hydrogen Peroxide; D042845:Laccase; D010544:Peroxidases; C051129:manganese peroxidase; D015032:Zinc