Mineralisation of 14C-labelled synthetic lignin and ligninolytic enzyme activities of litter-decomposing basidiomycetous fungi.
Within a screening program, 27 soil litter-decomposing basidiomycetes were tested for ligninolytic enzyme activities using agar-media containing 2,2'-azinobis(3-ethylbenzthiazoline-6-sulphonate), a humic acid or Mn2+ ions as indicator substrates. Most active species were found within the family Strophariaceae (Agrocybe praecox, Stropharia coronilla, S. rugosoannulata) and used for mineralisation experiments with a 14C-ring-labelled synthetic lignin (14C-DHP). The fungi mineralised around 25% of the lignin to 14CO2 within 12 weeks of incubation in a straw environment; about 20% of the lignin was converted to water-soluble fragments. Mn-peroxidase was found to be the predominant ligninolytic enzyme of all three fungi in liquid culture and its production was strongly enhanced in the presence of Mn2+ ions. The results of this study demonstrate that certain ubiquitous litter-decomposing basidiomycetes possess ligninolytic activities similar to the wood-decaying white-rot fungi, the most efficient lignin degraders in nature.
Steffen
K T
KT
Department of Applied Chemistry and Microbiology, University of Helsinki, Finland. Kari.Steffen@Helsinki.Fi
Hofrichter
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M
Hatakka
A
A
D001487:Basidiomycota / Q000201:enzymology* / Q000254:growth & development; D002250:Carbon Radioisotopes / Q000378:metabolism; D003470:Culture Media; D042845:Laccase; D008031:Lignin / Q000138:chemical synthesis / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D012987:Soil
D002250:Carbon Radioisotopes; D003470:Culture Media; D012987:Soil; D008031:Lignin; D010088:Oxidoreductases; D042845:Laccase; D010544:Peroxidases; C051129:manganese peroxidase