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The influence of gaseous oxygen concentration on fungal growth rates, biomass production and wood decay
1998 - IRG/WP 98-10283
The effects of air and several levels of oxygen balanced with nitrogen (% oxygen (v/v) nitrogen to 100%) on growth rates, biomass production and wood decay were investigated. The best technique for measuring daily growth rates in anaerobic jars was found to be by using 40 mm petri dishes which were attached to the walls of the jars. At the end of the test period the same petri dishes were also used for determining the dry weight of the fungal mycelia. The results showed that 5% oxygen concentration was very favourable for white rot and brown rot fungi (Basidiomycetes). When oxygen levels were reduced from 1% to 0.01%, the growth rates and dry weight of these fungi were steadily decreased. On the other hand, there was a large difference between very low oxygen levels (0.01 to 1%) and other levels (5 to 21% 02). In the case of other fungi there was not a big difference on their growth rates and biomass. Observational and numerical results on Fagus sylvatica (beech) and Pinus sylvestris (Scots pine) degradation by Coriolus versicolor, Coniophora puteana and Chaetomium globosum showed that there was a large difference in the degradation of the wood samples caused by C. puteana and C. versicolor when exposed to air and other levels of oxygen (0.25,1, 5 and 10% 02). Weight losses obtained by C. globosum as a soft rot on timber specimens in air and other oxygen levels were all in same range and below 5%. On the other hand there was a safety point at 5% 02 below which the fungus was unable to degrade beech. This point was 10% 02 for scots pine. At these points, weight losses were under 5%.
S M Kazemi, D J Dickinson, R J Murphy

Quantification of wood decay effects by HPLC analysis
1992 - IRG/WP 92-1576
The present work quantified the effects of the white rot basidiomycetes Coriolus versicolor and Phanaerochaete chrysosporium, and also those of the brown rot fungi Coniophora puteana and Lentinus lepideus, on Pinus patula and Eucalyptus grandis. Wood colonisation was quantified by Kjeldahl nitrogen determinations converted to biomass assays, and degradation was quantified by weight losses produced in the wood. Degraded wood samples were then analysed using high performance liquid chromatography (HPLC) of hydrolysates and their sugar contents were determined to establish whether the glucose of cellulose and xylose of hemicellulose had been utilised by the respective fungi. The extent and nature of sugar utilisation by each fungus in wood was then compared with the biomass and degradation data. Statistical analyses of these comparisons correlated the extents of colonisation, degradation, and the patterns of wood sugars predominantly utilised by each fungus. It was verified that the extent of wood conversion increased with biomass production. Importantly, the result of corresponding glucose and xylose analyses confirmed the brown rot physiological capacity a cellulolytic and hemicellulolytic, whereas that of the white rotters was primarily non-cellulolytic. In contrast, these analyses also showed that the white rotter Phanaerochaete chrysosporium demonstrated some cellulolytic and hemicellulolytic activity. The significance of these findings becomes apparent when colonised wood of apparent soundness is analysed as described here to determine whether or not decay was associated with such colonisation.
V Singh, M Tarin, G D Shelver, A A W Baecker

Estimates of wood-consumption rates by termites
1983 - IRG/WP 1201
Effects of 2 components; termite-biomass and experiment duration on estimates of wood-consumption rates (mg wood/g termite/day), were examined. Three models; (1) no mortality, (2) linear mortality and (3) nonlinear mortality were used to calculate mean standing-crop biomass of termites. Model (1) predicted a significantly lower wood-consumption rate than those based on models (2) and (3). No significant difference was detected between rates based on models (2) and (3) when data within defined experiment duration were used.
N-Y Su, J P La Fage

Estimation of mycelial biomass by determination of the ergosterol content of wood decayed by Coniophora puteana and Fomes fomentarius
1989 - IRG/WP 1415
The mycelial biomass of fungi decomposing wood materials may be estimated by the use of an ergosterol assay technique.ln decay tests, essentially according to EN 113, estimates made by HPLC analyses on wood decayed by Coniophora puteana and Fomes fomentarius show the increase in biomass in the wood blocks. The ergosterol contents were correlated with dry weight loss determinations. Degradation of wood in relation to colonization is discussed.
K Nilsson, J Bjurman

Fouling organisms as indicators of the environmental impact of marine preservative-treated wood
1995 - IRG/WP 95-50063
This study evaluates the use of fouling organisms (epibiota) to assess the environmental impact of preservative treated wood. This paper presents initial findings from treated panels exposed for 6 months at Sagres, Algarve, Portugal. Panels were treated with CCA, two copper-containing quaternary ammonium (ACQ) formulations and creosote, with nominal retentions from 10 to 40 kg/m³ (creosote 25 pcf). The presence of an abundant, diverse and healthy epibiotic community growing on treated wood was used as an indication that the preservative treatment had a relatively low impact on its immediate environment. Algae and mussels (Mytilus galloprovincialis) were the dominant members of the fouling community which developed on all preservative treated wood panels. The biomass (dry weight of organisms) and species diversity of epibiota scraped from the surface of preservative treated wood panels showed the following order CCA > Creosote > ACQ 1:1 > ACQ 2:1. No difference was detected concerning the shell dimension of mussels between treatments, but mussel biomass was much lower on ACQ-treated test samples, indicating that mussel settlement was affected by ACQ treatment, but growth was not. Algal biomass was highest on creosotetreated panels, with biomass on other panels fitting the following sequence: Creosote > CCA > ACQ 1:1 > ACQ 2:1. Copper, chromium and arsenic contents of algae were determined by atomic absorption spectroscopy (AAS). Elevated levels of Cu, Cr and As were found in the macroalgal mat from CCA-treated panels. These levels showed significant positive linear regressions with panel preservative retention levels. Higher levels of copper were found in macroalgal mats from ACQ-treated wood, but showed no linear relationship to panel preservative loadings. Copper levels did not exceed 9 ppm in algal tissue, chromium and arsenic levels were below 1 ppm.
R M Albuquerque, S M Cragg

Extracellular mucilage (ECM) in wood decay basidiomycetes
2002 - IRG/WP 02-10439
The ability of wood decay basidiomycetes to produce extracellular mucilage (ECM) and its relationship with total biomass production is being investigated. Growth and ECM production by the brown-rot fungus Gloeophyllum trabeum (FPRL 108 N) and the white-rot fungus Coriolus versicolor (CTB 863 A) was assessed in liquid culture under different conditions and in the presence of the fungicide cyproconazole. The production of biomass in G. trabeum was significantly influenced by the carbon source, monosaccharides stimulating increased biomass compared with oligosaccharides and polyols. The nitrogen source also significantly affected biomass production, with arginine and L-glutamic acid supporting maximum biomass. The best temperature for growth was 30°C, lower temperature causing a significant reduction in biomass production. The pH optimum for maximum growth was found to be 4.0. ECM production was influenced significantly by the nitrogen source, as well as by the pH of the medium and the temperature of incubation. The greatest proportion of ECM in the total biomass was produced by cultures incubated at 10°C (27% of the total biomass) and at pH 5.0 (16% of the total biomass). The same factors that affected the production of biomass and ECM in G. trabeum, also significantly affected C. versicolor. Again, simple monosaccharides supported the best growth. Amongst the nitrogen sources tested, L-glutamic acid stimulated maximum biomass production (double that of any other nitrogen source tested) whereas the greatest proportion of ECM in the total biomass was produced with arginine and isoleucine as nitrogen sources. The optimal temperature for growth was 22° C, whilst the optimum pH was 5.0. At 10°C the greatest proportion of ECM was produced, which represented about 24% of the total biomass. In terms of pH effects, the greatest proportion of ECM was produced at pH 6.0. The introduction of cyproconazole significantly reduced the amount of biomass produced by both organisms as expected. However, the production of ECM in both species was also affected greatly by the presence of biocide, with the proportion of ECM in the total biomass increasing significantly as the concentration of cyproconazole was raised. The results are discussed with regard to the possible role(s) of ECM in the decay process and its interaction with a specific organic preservative.
D Vesentini, D J Dickinson, R J Murphy

Effects of biocides on the extracellular mucilaginous material (ECMM) produced by two wood rotting basidiomycetes
2003 - IRG/WP 03-10469
Growth and production of extracellular mucilaginous material (ECMM) by the brown-rot fungus Gloeophyllum trabeum (FPRL 108 N) and the white-rot fungus Coriolus versicolor (CTB 863 A) was assessed in liquid culture, supplemented with the biocides CuSO4 and cyproconazole. The production of biomass in G. trabeum was significantly influenced by the concentration of CuSO4 in the medium. When CuSO4 was added at 1.0 mmols l-1, biomass was reduced by approximately 35%. At this concentration, the production of ECMM, both absolute and relative to biomass, was increased. Cyproconazole had a similar effect to that observed for CuSO4, although much lower concentrations of the biocide were required to achieve a similar response. Addition of 0.1 mmols l-1 of cyproconazole to the growth medium caused a decrease of approximately 35% in the amount of biomass produced and a 200% increase in the proportional amount of ECMM produced by the fungus. A similar behaviour was also confirmed for C. versicolor . In this case, higher concentrations of CuSO4 were required in order to achieve the same levels of inhibition observed for G. trabeum. Cyproconazole-supplemented cultures also behaved similarly to G. trabeum. A concentration of cyproconazole of 0.1mmols l-1 caused a reduction of 50% in biomass and a 100% increase in the proportional amount of ECMM produced by this fungus. The presence of biocide also led to qualitative changes in the composition of ECMM. Galactose, xylose and glucose were the main components of the polysaccharide fractions of the ECMM produced by the two species growing on control media. As biocides were introduced, the proportion of galactose in the ECMM increased. This was always associated with a decrease in the proportion of glucose for G. trabeum and with a decrease in the proportion of xylose in the ECMM produced by C. versicolor. The results are discussed with regard to the possible role(s) of ECMM in the decay process and its interaction with preservative treatments.
D Vesentini, D J Dickinson, R J Murphy

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 purification and the conventional measurement methods. The production of melanin was clearly dependent on the amount and quality of carbon source as well as the amount of nitrogen. A. pullulans has a high tendency to produce melanin on nitrogen poor media supplemented with easily soluble sugars (eg. glucose, sucrose, mannose and xylose). The production was restricted on nitrogen rich media. The production of melanin was totally inhibited on the media containing celluloses or lignin as sole carbon sources.
A-C Ritschkoff, M Rättö, F Thomassin

A Review of Wood as Material and Source of Innumerable Products
2008 - IRG/WP 08-10662
As we known that “wood –which is a source of innumerable pruducts (Tsoumis, 1968)– is a fascinating and challenging material (Dinwoodie, 1975)”, and hence, “an understanding of the basic properties of wood and of the factors that affect its serviceability is vital background for the preservation of wood structures (Sherwood, 1986)”. This paper therefore presents an overview of structrural properties of wood (based on the softwood species) and the aspect of of wood material for its serviceabilty. The emphasis was given to introduce wood as a material and a source of innumerable products by the detailed coverege of the subject.
I Usta, R Despot

Wood characterization of Tetraclinas articulata and evaluation of its resistance against lignilolytic fungi
2009 - IRG/WP 09-10697
Coniferous trees of the Tetraclinis articulata known under the Common name thuja from Berberie, is an endemic species from North Africa. The solid wood is much appreciated for its natural beauty and homogeneity and its quality for marquetry and furniture. The aim is to improve Tetraclinis articulate uses. At present, its wood is widely underestimated and sub-used compared to its announced qualities. Previous studies have shown that the Cupressaceous, to which the thuja belongs, possesses extractable compounds called tropolones considered as being responsible for their natural durability. A first objective is to analyse the inherent characteristics of Tetraclinis articulatasolid, a solid wood originated from Morocco, based on its physical and mechanical properties because there is little scientific data in the literature related to the quality of this species of wood. A second one is to assess the anti fungus potentials of thuja sawdust or woodchip recovered at the end of processing the timber. Indeed, the extraction of tropolones can be expensive and unprofitable, it seems therefore interesting to test the anti fungal activities and consider the possibility of incorporating them into particle board and test their durability. We have performed physical and mechanical tests and conducted biological degradation tests. Microbial resistance properties have been investigated to show any possible decay zones in the samples. Preliminary results of the biocides activities in sawdust show that rates from 1 to 2 % of sawdust, incorporated in the culture medium, limit the development of degradation agents as Coriolus Versicolor. In this context, the use of sawdust in an industrial scale in Morocco would be an environmental challenge and an answer to the challenges required, among others, by evaluation of local biomass and the reduction of the use of organic and mineral biocides.
F El Bouhtoury-Charrier, A Hakam, A Famiri, M Ziani, B Charrier

The Chelator Mediated Fenton System in the Brown Rot Fungi: Details of the Mechanism, and Reasons Why it has Been Ineffective as a Biomimetic Treatment in some Biomass Applications – a Review
2014 - IRG/WP 14-10828
The chelator-mediated Fenton (CMF) reaction requires the action of two types of chelating compounds. The first chelator, oxalate, solubilizes and then sequesters iron, and the second chelator reduces iron. Iron reduction must be controlled near the fungal hyphae to prevent damaging Fenton chemistry from occurring in that location. Similarly, iron reduction must be promoted within the wood/plant cell wall to promote Fenton chemistry in the proximity of the target lignocellulose. The mechanism for that control is reviewed in this paper. Both neat Fenton and the CMF have been examined by researchers seeking to exploit this relatively simple mechanism for biomass conversion and lignocellulose pretreatment systems. This paper reviews why some of that research has not produced useful depolymerization reactions and why excess amounts of reagents have been required. The application of Fenton treatments requires that the reactive oxygen species produced in the reaction be generated within a nanometer of the target substrate (lignocellulose), and for this to occur in biomass treatments using Fenton or CMF systems, iron must first be allowed to bind to the substrate to allow the reactions to proceed within nanoscale proximity to lignocellulose. Further, excess iron in solution and in interstitial space must be removed as this “free” iron will react preferentially with chelators and peroxide preventing appropriate targeted action on lignocellulose.
B S Goodell, M Nakamura, J Jellison

In Vitro Growth of the Basidiomycetes Physisporinus vitreus strains in various conditions in comparison with some white rot fungi
2022 - IRG/WP 22-10987
The paper has preliminary test results to select Pysisporinus vitreus fungal strains for further experiments in a large research project on copper tolerance of P. vitreus by chemotropic test, choice test, and agar plate toxicity tests and determination of the effect of various ions on oxalic acid secretion by these white rot fungi. In the project, it is also aimed to run fungal decay tests to determine nano and soluble-Cu tolerance of the test fungi and Cu depletion by the fungi. A myco-remediation process of nano and soluble-Cu-treated wood by the test fungi in liquid media is also planned to determine the effect of the ions on their remediation potential. Twelve P. vitreus and nine white rot fungal strains were tested to determine optimum growth conditions in both solid malt extract agar (MEA) or potato dextrose agar (PDA) plates and liquid (N-rich and standard) media. The growth media was also regulated to different pH degrees. Radial growth of the fungi was monitored for 12 days on the media. At the end of the incubation period, the mycelial biomass and the medium pH were also determined. Considering the growth and biomass production by the fungi, MEA at 5.6 as solid medium and the standard liquid media at 5.6 and 7 were determined as most suitable artificial media. In all cases, the media at pH 9 provided unfavorable conditions for fungal growth. P.vitreus FP71186, P.vitreus ME441, and P.vitreus P151 strains were selected for further steps of the project based on their growth rate, biomass production and their capability to lower pH levels.
E E Soytürk, S N Kartal

Impregnation of wood with antifungal compounds from low-quality tree biomass
2022 - IRG/WP 22-30763
In this paper we have reviewed recent research on the development of bio-based preservative formulations for wood done at the Department of wood science and technology, Ljubljana. Preservative formulations used in this investigation were prepared using plant polyphenols as biocidal agents. These nonstructural components of wood were stilbenes and flavonoids, and were extracted from wood of broken and less-utilized trees, respectively. Woody biomass of the lowest quality was selected as a row material for extraction. Pine knotwood (Pinus sylvestris and Pinus nigra) and black locust heartwood (Robinia pseudoacacia) were extracted with acetone. Obtained extracts were examined with gravimetrically, spectrophotometrically and with chromatographic analysis. Further on, purified stilbenes and flavonoids were prepared for the antifungal assay. The extracts were colorimetrically analyzed on antioxidant properties by measuring free radical scavenging activity. The resistance of with extractives impregnated wood was measured with a so-called mini-block test (modified EN 113). Wood of less durable conifers and deciduous tree species was impregnated in a vacuum-pressure chamber, whereat water solutions of the hydrophilic extracts were used. After impregnation, the retention of extracts in the wood matrix was examined gravimetrically and with microscopy (CLSM and SEM). Antifungal properties of wood extractives of pine and black locust were determined by in vitro measuring the inhibition of fungal growth, and with measuring the resistance of the impregnated wood against fungal decay. The results of the fungal tests clearly show that hydrophilic extractives of less-quality wood of pines and black locust inhibit both fungal growth and reduced fungal decay of wood. It was found that the wood extracts of pines and black locust can be referred as to natural antioxidants since they inhibited the activity of free DPPH radicals. The results of our investigation show that low-quality wood of broken and less-utilized trees can be explained as a relevant source of natural compounds with antifungal and antioxidant properties. Wood polyphenols could be used as natural biocidal agents in bio-based preservative solutions.
V Vek, I Poljanšek, A Balzano, M Humar, P Oven