Ceriporic Acid B, an Extracellular Metabolite of Ceriporiopsis subvermispora, Suppresses the Depolymerization of Cellulose by the Fenton Reaction

Abstract

The white rot fungus, Ceriporiopsis subvermispora, is able to degrade lignin in wood without intensive damage to cellulose. Since lignin biodegradation by white rot fungi proceeds by radical reactions, accompanied by the production of a large amount of Fe3+-reductant phenols and reductive radical species in the presence of iron ions, molecular oxygen, and H2O2, C. subvermispora has been proposed to possess a biological system which suppresses the production of a cellulolytic active oxygen species, *OH, by the Fenton reaction. In the present paper, we demonstrate that 1-nonadecene-2,3-dicarboxylic acid (ceriporic acid B), an extracellular metabolite of C. subvermispora, strongly inhibited *OH production and the depolymerization of cellulose by the Fenton reaction in the presence of iron ions, cellulose, H2O2, and a reductant for Fe3+, hydroquinone (HQ), at the physiological pH of the fungus.

Iron cycling during the autocatalytic decomposition of benzoic acid derivatives by Fenton-like and photo-Fenton techniques

“…Hence, we have shown that, in line with results reported in the presence of aliphatic chelates such as oxalate [9], Fe(III) reduction may also be suppressed in the presence of strong aromatic complexing agents. These observations have important implications for the kinetics of degradation of organic pollutants in Fenton-like systems.…”

“…For instance, it is well-known that the presence of high oxalate concentrations suppresses the production of hydroxyl radicals in Fenton-like systems operated under dark conditions. In general, as the stability of a given Fe(III)-chelate increases it becomes more difficult to reduce, in some cases in spite of an appropriate standard reduction potential [8,9]. For the latter systems, kinetic restrictions, such as the existence of accessible sites in iron complexes, are also important factors that control the overall reduction rates.…”

Cellobiose Dehydrogenase from the Ligninolytic Basidiomycete Ceriporiopsis subvermispora

“…This mechanism seems unlikely for C. subvermispora, as the production of alkylitaconic (cereporic) acids in the early stages of wood degradation was reported. These cereporic acids inhibit hydroxyl radical production by forming complexes with Fe 2ϩ or Fe 3ϩ ions (40,48). However, in later culture stages alkylitaconic acids are not formed anymore and CDH could then support Fenton's chemistry (17,19).…”

Mecanismos envolvidos na biodegradação de materiais lignocelulósicos e aplicações tecnológicas correlatas

“…49 A ocorrência de ácidos alquil-itacônicos no meio extracelular dos cultivos de alguns fungos seletivos para degradar lignina certamente previne a degradação de celulose. 81 No entanto, do ponto de vista evolutivo, o fungo não deve ter desenvolvido um sistema que o limitasse na capacidade de metabolizar fontes de carbono energéticas como a celulose. O mais provável é que os ácidos alquil-itacônicos também sejam substratos para processos de peroxidação e consequente geração de radicais peroxila, que teriam como função principal a degradação de lignina.…”