Your search resulted in 17 documents.
The influence of crystalline and amorphous cellulose on extracellular hydrogen peroxide production by brown-rot fungi
1991 - IRG/WP 1482
The production of hydrogen peroxide (H2O2) has been suggested to play a key role in the degradation of wood by wood-rotting fungi. The production of extracellular hydrogen peroxide was studied by a quantitative method which detects the oxidation of the 2,2-azinobis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) by H2O2 and horseradish peroxidase (HRP) in liquid culture medium. The carbon sources u...
A-C Ritschkoff, L Viikari
Prevention of brown-rot decay by chelators
1992 - IRG/WP 92-1540
In this work the brown-rot decay was shown to be prevented by chelating the endogenous metals existing in wood by using organic or inorganic chelators or iron-binding siderophores. The fungal growth and decaying ability were significantly decreased by the chelating treatments of the solid wood-based culture medium and pine wood pieces, respectively. The transition metals existing in native wood ar...
L Viikari, A-C Ritschkoff
The preliminary characterization of ß-1,4-xylanase of the brown-rot fungus Gloeophyllum trabeum
1990 - IRG/WP 1447
The extracellular ß-1,4-xylanase of the brown-rot fungus, Gloeophyllum trabeum, was isolated from crude extract by chromatofocusing method (PBE 94 column chromatography). The isoelectric point was estimated to 4.2-4.8 by cromatofocusing and 4.5 by isoelectric focusing (IEF). The molecular weight of the enzyme was estimated to 37,000 dalton by SDS-PAGE. The optimal temperature for the crude extrac...
A-C Ritschkoff, M Rättö, L Viikari
Report of Section 1 2002
2002 - IRG/WP 02-10455
A-C Ritschkoff
Effect of mineral wools on growth and decay capacities of Serpula lacrymans and some other brown-rot fungi
1991 - IRG/WP 1481
The influence of stone wool and glass wool on growth and decay capacities of Serpula lacrymans and some other brown-rot fungi was studied. Mass losses of pine wood caused by Serpula lacrymans and Gloeophyllum trabeum were increased when stone wool was present. Glass wool had no influence on mass losses. Coniophora puteana, Serpula lacrymans and Gloeophyllum trabeum grew into stone wool and destroy...
L Paajanen, A-C Ritschkoff
Iron in stone wool - one reason for the increased growth and decay capacity of Serpula lacrymans
1992 - IRG/WP 92-1537
The chemical compositions of stone wool and glass wool were analysed. There was more iron in the stone wool than in the glass wool. It was found that iron present in stone wool was easily dissolved by oxalic acid that Serpula lacrymans is able to produce. The stone wool promoted the decay of pine wood by Serpula lacrymans. The glass wool had no effect on the decay capacity of Serpula Iacrymans. Th...
L Paajanen, A-C Ritschkoff
Environmental risk assessment of treated timber in service: The Environment Focus Group approach
2000 - IRG/WP 00-50162
In the context of the Biocidal Products Directive (98/8/EC), and of the OECD work on wood preservatives, the Environment Focus Group (EFG), comprising 8 institutes and the European Wood Preservative Manufacturers Group, has been working on the environmental risk assessment of treated timber in service. A literature review of emissions from treated timber has revealed that very little existing data...
G Deroubaix, G Labat, I Le Bayon, S Legay, P Marchal, C Yrieix, E Melcher, R-D Peek, S De Geyter, J Van Acker, W J Homan, D J Dickinson, R J Murphy, E D Suttie, A J Nurmi, A-C Ritschkoff, D Rudolph, I Stephan, D Aston, E F Baines, J B Simonin
Moisture requirements and wood degradation of pine and spruce wood by some Basidiomycetes-fungi
1989 - IRG/WP 1406
The minimum moisture requirements for the growth of the brown rot fungi, Coniophora puteana, Gloeophyllum trabeum and Serpula lacrymans were near or above the fibre saturation point of pine and spruce, sap and heartwood, during 160 days incubation according to the standard method EN 113. The moisture of wood for the optimum growth of Coniophora puteana and Serpula lacrymans was about 35-80% and fo...
H Viitanen, A-C Ritschkoff
Preliminary studies of the decay mechanism of some brown-rot fungi
1989 - IRG/WP 1402
The importance of the enzymatic degradation of hemicellulose and cellulose by brown-rot fungi is still under discussion. Endo-ß-1,4-xylanase and endoglucanase activities of Coniophora puteana and Poria placenta cultures were measured by the increase in reducing groups. Enzymes were produced in liquid and solid sawdust based culture media. Enzyme activities were measured in two, four and eight wee...
A-C Ritschkoff, H Viitanen
Fenton's reagent as a modification tool in brown-rot decay
1996 - IRG/WP 96-10155
A biomimetic approach was used to clarify the role and importance of the Fenton-type reaction in the carbohydrate degradation by brown-rot fungi. Spruce sawdust and microcrystalline cellulose were modified in the H2O2/Fe(II) treatment. The degree of hydrolysis of the pretreated spruce sawdust was clearly increased with the complete cellulase (Econase), purified endoglucanase from Trichoderma reese...
M Rättö, A-C Ritschkoff, J Buchert, L Viikari
Production of exraxellular hydrogen peroxide and oxalic acid by brown-rot fungus Poria placenta
1995 - IRG/WP 95-10112
Hydrogen peroxide and oxalic acid have been suggested to be essential in the degradation of wood carbohydrates by brown-rot fungi. Hydrogen peroxide has been suggested to be one of the diffusible low molecular weight agents produced by brown-rot fungi for the degradation of wood carbohydrates by generating highly active radicals. The production of hydrogen peroxide and oxalic acid by Poria placent...
A-C Ritschkoff, M Rättö, J Buchert, L Viikari
The role of oxidation in wood degradation by brown-rot fung
1992 - IRG/WP 92-1562
Brown-rot fungi are suggested to degrade cellulose by oxidation with hydrogen radicalsformed eg. in the conversion of hydrogen peroxide in the Fenton type reactions. The stuctural changes in the holocellulose in wood induced by Fenton's reaction on wood components are very similar to those caused by brown-rot fungi. In this work the effect of the Fenton reaction on wood components was stu...
A-C Ritschkoff, J Pere, J Buchert, L Viikari
Effect of some resin treatments on fungal degradation reactions
1999 - IRG/WP 99-10318
The effect of impregnation of wood with vegetable oil, tall oil and two water soluble on fungal degradation reactions was assessed by hydrolysis and enzyme activity measurements. The experiments were carried out by using isolated enzyme preparations and a living brown-rot fungus Poria placenta. The results indicate that the inhibitory effect of treatments was clearly directec towards the enzymatic...
A-C Ritschkoff, M Rättö, A J Nurmi, H Kokko, A O Rapp, H Militz
Effect of crude tall oil, linseed oil and rapeseed oil on the growth of the decay fungi
2002 - IRG/WP 02-30299
The influence of crude tall oil, linseed oil and rapeseed oil on the growth of Coniophora puteana, Poria placenta and Coriolus versicolor was studied. The selected test oils were observed to have different effects on the the fungal growth. Crude tall oil inhibited the radial growth of all fungi. Rapeseed oil either accelerated or inhibited the growth of fungi depending on the type of fungus involv...
L Paajanen, A-C Ritschkoff
The production of extracellular hydrogen peroxide by some brown-rot fungi
1990 - IRG/WP 1446
The role of hydrogen peroxide (H2O2) has been discussed in the degradation of wood by wood-rotting fungi. The production of extracellular hydrogen peroxide was studied by detecting the oxidation of the chromogen 2,2'-azinobis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) by H2O2 and horse radish peroxidase (HPR). ABTS and HPR were added to a solid wood based culture media. In this study ...
A-C Ritschkoff, L Paajanen, L Viikari
Influence of the nutritional elements on pigmentation and production of biomass of bluestain fungus Aureobasidium pullulans
1997 - IRG/WP 97-10198
The effect of the carbon source and the amount of the nitrogen on the melanization and the production of mycelial mass of bluestain fungus Aureobasidium pullulans was studied by using solid state cultivations. The carbon sources used varied from easily soluble sugars to structural polysaccharides existing in lignocellulosic material. The amount of melanin was evaluated by using partial purificatio...
A-C Ritschkoff, M Rättö, F Thomassin
The identification of the carbohydrate degrading enzymes from the crude extract of brown-rot fungus Gloeophyllum trabeum
1991 - IRG/WP 1483
The brown-rot fungus, Gloeophyllum trabeum, produces a pattern of carbohydrate degrading enzymes during the wood decay. In liquid sawdust media the activities of endo-b-1,4-gluganase and endo-b-1,4-xylanase were at the maximum after 5-6 weeks cultivation. The production of enzymes started immediately after inoculation suggesting that the degradation of hemicellulose and easily degradable parts of ...
A-C Ritschkoff, J Buchert, L Viikari