Production of lignocellulose-degrading enzymes and degradation of leaf litter by saprotrophic basidiomycetes isolated from a Quercus petraea forest

• Published in: Soil biology & biochemistry Vol. 39; no. 10; pp. 2651 - 2660
• Main Authors: Valášková, Vendula, Šnajdr, Jaroslav, Bittner, Britta, Cajthaml, Tomáš, Merhautová, Věra, Hofrichter, Martin, Baldrian, Petr
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-10-2007; New York, NY Elsevier Science
• Subjects: Agronomy. Soil science and plant productions; Basidiomycetes; Basidiomycota; Biochemistry and biology; biodegradation; Biological and medical sciences; Cellulose; Chemical, physicochemical, biochemical and biological properties; detritivores; enzyme activity; enzymes; forest litter; forest soils; Fundamental and applied biological sciences. Psychology; Gymnopus; Hemicelluloses; Hypholoma fasciculare; Laccase; Lignin; lignocellulose; Litter-decomposing basidiomycetes; microbial colonization; Mn-peroxidase; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Quercus petraea; Rhodocollybia; Rhodocollybia butyracea; soil fungi; Soil science; Czech Republic; Hypholoma fasciculare; Lignin; Hemicelluloses; Mn-peroxidase; Cellulose; Litter-decomposing basidiomycetes; Quercus petraea; Laccase; Forests; Hemicellulose; Basidiomycetes; Decomposition; Fungi; Hypholoma; Dicotyledones; Angiospermae; Hardwood forest tree; Soil science; Thallophyta; Litter; Enzyme; Plant leaf; Lignocellulosics; Fagaceae; Saprobiosis; Soils; Peroxidases; Enzymatic digestion; Spermatophyta; Oxidoreductases
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/j.soilbio.2007.05.023

Due to the production of lignocellulose-degrading enzymes, saprotrophic basidiomycetes can significantly contribute to the turnover of soil organic matter. The production of lignin- and polysaccharide-degrading enzymes and changes of the chemical composition of litter were studied with three isolates from a
Quercus petraea forest. These isolates were capable of fresh litter degradation and were identified as
Gymnopus sp.,
Hypholoma fasciculare and
Rhodocollybia butyracea. Within 12 weeks of incubation,
H. fasciculare decomposed 23%,
R. butyracea 32% and
Gymnopus sp. 38% of the substrate dry mass. All fungi produced laccase and Mn-peroxidase (MnP) and none of them produced lignin peroxidase or other Mn-independent peroxidases. There was a clear distinction in the enzyme production pattern between
R. butyracea or
H. fasciculare compared to
Gymnopus sp. The two former species caused the fastest mass loss during the initial phase of litter degradation, accompanied by the temporary production of laccase (and MnP in
H. fasciculare) and also high production of hydrolytic enzymes that later decreased. In contrast,
Gymnopus sp. showed a stable rate of litter mass loss over the whole incubation period with a later onset of ligninolytic enzyme production and a longer lasting production of both lignin and cellulose-degrading enzymes. The activity of endo-cleaving polysaccharide hydrolases in this fungus was relatively low but it produced the most cellobiose hydrolase. All fungi decreased the C/N ratio of the litter from 24 to 15–19 and
Gymnopus sp. also caused a substantial decrease in the lignin content. Analytical pyrolysis mass spectrometry of litter decomposed by this fungus showed changes in the litter composition similar to those caused by white-rot fungi during wood decay. These changes were less pronounced in the case of
H. fasciculare and
R. butyracea. All fungi also changed the mean masses of humic acid and fulvic acid fractions isolated from degraded litter. The humic acid fraction after degradation by all three fungi contained more lignin and less carbohydrates. Compared to the decomposition by saprotrophic basidiomycetes, litter degradation
in situ on the site of fungal isolation resulted in the relative enrichment of lignin and differences in lignin composition revealed by analytical pyrolysis. It can most probably be explained by the participation of non-basidiomycetous fungi and bacteria during natural litter decomposition.