IRG Documents Database and Compendium

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Enzyme immunoassay to detect Postia placenta in field tests: Comparison of plate ELISA with hydrophobic cloth and cotton dipstick
1991 - IRG/WP 2378
Standard indirect enzyme-linked immunosorbent assay in polystyrene 96-well plates was compared to hydrophobic polyester cloth and cotton dipstick for detection of wood-derived antigens from the brown-rot fungus Postia placenta. The ease of handling, larger surface area, and economics of the latter two adsorbents were surveyed for application as field tests for detection of early decay. At high antibody concentrations, the cloth ELISA (C-ELISA) exibited sensitivity comparable to the plate ELISA (P-ELISA), but at lower antibody concentrations signals diminished more rapidly for the C-ELISA. The dipstick assay lacked sensitivity even at high antibody concentrations, and suffered from inability to block a high nonspecific background. Nonporous polystyrene was judged superior to C-ELISA and cotton dipstick as the immobilizing phase for detecting antigen from Postia placenta by immunoassay, although at high antibody concentrations and increased incubation periods, C-ELISA matched the sensitivity of P-ELISA.
C A Clausen

A technique for assessing the preventive efficacy against decay fungi of preservative treatments applied to wood
1988 - IRG/WP 2309
A method is described in which test blocks with envelope preservative treatments can be challenged by selected test fungi previously established on an untreated feeder block. The progress of the test fungus through the treated zone is monitored using novel baits or sensors inserted in holes drilled into blocks to within predetermined distances of the face being challenged. Preliminary results show the method to be discriminating. Three minute immersion treatment with 5% PCP retarded colonisation for a longer period than 1% TnBTO particularly when penetration was in the tangential direction.
J K Carey, A F Bravery

Suitability of cotton strip testing as a screening method for the development of wood preservative formulations
2003 - IRG/WP 03-20270
This paper outlines a simple and rapid test method for screening the efficacy of wood preservative formulations against microbiological attack using cotton strips. The method was evaluated against soft rot and was found to provide reliable information on the protection of lignocellulosic material against microbiological attack. The assessment is based on visual interpretation of decay and on a simple strength test of the cotton strip. The experience obtained with this method at BFH and BAM by testing in parallel a well investigated copper containing preservative revealed a good prediction of the effective concentration on wood. The results of the cotton strip screening test were compared with ENV 807 test results as well as with data from fungus cellar testing (5 year results) and a field trial (EN 252, 5 years).
H Leithoff, I Stephan, H Härtner

Targeted inhibition of wood decay fungi: degradation of cotton cellulose
1999 - IRG/WP 99-10321
Brown-rot decay is responsible for 80% of the damage and replacement of wood in service. For nearly thirty years, researchers have postulated a one-electron oxidase system combining Fe+2 oxalic acid, and H2O2 in the production of hydroxy radicals which ultimately oxidize cellulose in situ. Recently, researchers have been investigating antioxicants, in combination with biocides (Schultz, et al.,1998), as targeted inhibitors of the decay process and potential wood preservatives. In order to target the cellulolytic mechanisms of brown-rot and white-rot decay fungi, cotton cellulose was treated with free radical scavengers, antioxidants, dyes and hydroxy-radical detectors 2,2'-Azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) in order to assess their ability to retard cellulose hydrolysis. Weight loss of cotton cellulose is the most reliable and accurate measure of exoglucanase activity. Cotton cellulose was exposed to G. trabeum MAD 617, T. palustris 6137 and T. versicolor MAD 697 in soil-block tests. After 12 weeks exposure, cotton was evaluated for weight loss, change in DP, and elemental analysis by ICP spectroscopy. Only 2 out of 11 compounds tested (NHA and ruthenium red) showed less than 1% weight loss for all three fungi tested. All other compounds were selective, underscoring difficulties in sharply targeting decay mechanisms. Weight loss and DP of cellulose are analogous to degradation and strength loss of wood caused by decay fungi.
F Green III, T A Kuster

Chemical mediated depolymerization of cotton cellulose for the understanding of non-enzymatic fungal decay
2010 - IRG/WP 10-10731
Small, low molecular weight non-enzymatic compounds have been linked to the early stages of brown rot decay as the enzymes involved with holocellulose degradation are found to be too large to penetrate the S3 layer of intact wood cells. The most pronounced of these which were analyzed in this study are hydrogen peroxide, iron, and oxalic. The compounds related to the Fenton reaction: the combination of hydrogen peroxide and iron caused marked lowering of the degree of polymerization in the cotton cellulose after treatment. This was the case for both iron ions; Fe3+ and Fe2+. A 10mM solution of oxalic acid also showed significant depolymerizing effect on cotton cellulose, whereas diluting the oxalic acid with sodium oxalate to obtain a pH gradient, showed that this decreased the effect reducing of oxalic acid. In addition an organic iron chelator, EDTA, was tested but was found to inhibit depolymerization when in solution with chemicals related to Fenton chemistry. Manganese was tested to see if other metals than iron could generate an significant impact on the degree of polymerization of cotton cellulose and the metal showed good depolymerizing properties as a substitute for iron. We conclude that low molecular weight metabolites are capable of effectively depolymerizing cellulose during incipient decay by brown-rot fungi.
A C Steenkjær Hastrup, B Jensen, F Green III

Efficacy of lignocellulosic materials for Removal of Cation and Anions from Industrial and Urban Wastewater
2016 - IRG/WP 16-50321
The adsorption of Ca, Zn, Na, Cd (II), Cr (III) and No3 ions from industrial and urban wastewater and aqueous solutions by poplar (Populusnigra) sawdust, cotton linter, zeolite and expanded perlite were examined on the basis of a batch adsorption technique. The results revealed that application of sawdust, cotton linter, perlite and zeolite are effective in improving elimination of Ca, Zn, Na ions from industrial and urban wastewater and Cd (II), Cr (III) and No3 from aqueous solutions. Generally, Ca, Zn, Na removal efficiency of mixture of W+α+P+Z was reported to be higher than other adsorbents. The removal efficiency of heavy metals with W and mixture of W+α were reported to be higher than other adsorbents. Also the results indicated that adsorbents were effective on total dissolved solids (TDS) removal from petrochemical and rural wastewater.
M Akhtari, M Ghorbani Kohkandeh, H Borazjani