Oxalate found in wood cell wall during incipient brown rot degradation. (February 2023)

• Record Type: Journal Article
• Authors: Füchtner, Sophie; Alfredsen, Gry; Thygesen, Lisbeth G.
• Is Part Of: International biodeterioration & biodegradation. Volume 177(2023)
• Publication Date: 2023-02
• Subjects: In situ localization -- Picea abies -- Raman microscopy -- Rhodonia placenta; Biodegradation -- Periodicals; Bioremediation -- Periodicals; Biodegradation -- Periodicals; Biodégradation -- Périodiques; Biorestauration -- Périodiques; Electronic journals; 620.11223
• DOI: 10.1016/j.ibiod.2022.105531
• Languages: English
• ISSNs: 0964-8305

Abstract

Abstract: Brown rot fungi are a marvel and an enigma of Nature. They are capable of depolymerizing holocellulose within wood cell walls without significantly mineralizing lignin. The exact details behind this feat remain unknown, but a staggered mechanism has been identified: 1) an initial step characterized by oxidative degradation of the wood cell wall biopolymers and hypothesized to involve transport of Fe 3+ chelated by oxalate into the cell wall, and 2) a second degradation step dominated by hydrolytic enzymes, primarily endoglucanase activity. We subjected spruce wood ( Picea abies ) to Rhodonia placenta and isolated xylem tissue in the initial stage of degradation. Confocal Raman microscopy revealed oxalate accumulation in the secondary cell wall of a tracheid having fungal hyphae within the lumen. This observation is the first in situ verification of oxalate accumulation within the cell wall during the first step of brown rot degradation. Highlights: Oxalate found in the wood cell wall during insipient brown rot decay. Raman microscopy and chemometrics allowed identification of hyphae and oxalate. Oxalate accumulation in cell walls during brown rot decay was hypothesized in 1997.