International Biodeterioration & Biodegradation 55 (2005) 203–211 Synergistic wood preservatives involving EDTA, irganox 1076 and 2-hydroxypyridine-N-oxide A. Mabicka a , S. Dumarc - ay a , N. Rouhier b , M. Linder c , J.P. Jacquot b , P. Ge´rardin a , E. Gelhaye b,Ã a Laboratoire d’Etudes et de Recherches sur le Mate´riau Bois, UMR INRA 1093, Universite´Henri Poincare´Nancy I, Faculte´des Sciences, BP 239, 54506 Vandoeuvre-le`s-Nancy, France b UMR INRA 1136, Interactions Arbres Micro-organismes, Universite´Henri Poincare´Nancy I, Faculte´des Sciences, BP 239, 54506 Vandoeuvre-le`s-Nancy, France c Laboratoire de Physico-chimie et Ge´nie Alimentaire, Ecole Nationale Supe´rieure d’Agronomie et Industries Alimentaires (ENSAIA), 54505 Vandoeuvre-le`s-Nancy, France Abstract Theefficiencyof2-hydroxypyridine-N-oxide(2-HPNO)againstwooddegradationbythewhite-rotfungus Coriolus versicolor was demonstratedbymonitoringweightlossoftreatedanduntreatedwoodblocks.Thefungistaticpropertiesof2-HPNOarerelatedto the presence of the hydroxamic acid function as shown using several analogs. Using response surface methodology, strongly significantsynergywasobservedbetweeneitherthechelatorethylenediaminetetraaceticacid(EDTA)and2-HPNOorthehindered phenolicantioxidantIrganox1076and2-HPNO.2-HPNOissubjectedtooxidationbyperoxidaseexplainingthesynergyobserved with the antioxidant. The chelating properties of 2-HPNO may also explain the synergy observed with EDTA. The implications of the observed synergy for the design of new wood preservation strategies are also discussed. r 2005 Elsevier Ltd. All rights reserved. Keywords: Fungicide; Chelator; Antioxidant; Synergy; Wood degradation; Wood rotting fungi 1. Introduction Wood products are extensively used for a variety of purposes, such as residential construction, utility poles, etc., but, as a natural organic material, wood is degraded by many organisms, especially fungi. The use of traditional wood preservatives as chromated copper arsenate(CCA)orcreosoteisincreasinglycomingunder scrutiny, since questions concerning the environmental acceptability of biocides in general become more prominent both socially and politically (Hingston et al., 2001). New preservatives designed to deal specifi- cally with wood degradation processes could be envisagedasalternativestotraditionalmethods(Schultz and Nicholas, 2002). The degradation of lignocellulose by fungi is a complex phenomenon, which is only partially under- stood.Lignocellulolyticenzymesareunabletopenetrate in the wood cell wall in the early stages of decay (Cowling, 1961). It has also been proposed that low molecular mediators are involved in this process initiating depolymerization of wood cell wall consti- tuents (Goodell et al., 1997; Hammel et al., 2002; Milagres et al., 2002). These small molecular weight agents in conjunction with metals could also mediate oxidative reactions. Taking into account these mechan- isms of wood degradation, several authors have proposed the use of chelators as wood preser- vatives (Green et al., 1997; Schultz and Nicholas, 2002). In earlier papers, our laboratory has reported ARTICLE IN PRESS www.elsevier.com/locate/ibiod 0964-8305/$-see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.ibiod.2005.01.002 Ã Corresponding author. E-mail address: gelhaye@lcb.uhp-nancy.fr (E. Gelhaye).