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Cleavage of the arylglycerolb-aryl ether linkage is the most important process in the biological degradation of lignin. Thebacterialb-etherasewasdescribedpreviouslyandshown to be tightly associated with the cellular membrane. In this study, we aimed to detect and isolate a new extracellular function that catalyses theb-aryl ether linkage cleavage of high-molecular lignin in the soil fungi. We screened and isolated 2BW-1 cells by using a highly sensitive fluorescence assay system. | Eur. J. Biochem. 270 2353-2362 2003 FEBS 2003 doi 10.1046 j.1432-1033.2003.03545.x Detection and characterization of a novel extracellular fungal enzyme that catalyzes the specific and hydrolytic cleavage of lignin guaiacylglycerol p-aryl ether linkages Yuichiro Otsuka1 Tomonori Sonoki1 Seiichiro Ikeda1 Shinya Kajita1 Masaya Nakamura2 and Yoshihiro Katayama1 1Graduate School of Bio-Applications and Systems Engineering Tokyo University of Agriculture and Technology Koganei Tokyo Japan 2Forestry and Forest Products Research Institute Microbial Technology Laboratory Tsukuba Norin Kenkyu Danchi-nai Ibaraki Japan Cleavage of the arylglycerol b-aryl ether linkage is the most important process in the biological degradation of lignin. The bacterial b-etherase was described previously and shown to be tightly associated with the cellular membrane. In this study we aimed to detect and isolate a new extracellular function that catalyses the b-aryl ether linkage cleavage of high-molecular lignin in the soil fungi. We screened and isolated 2BW-1 cells by using a highly sensitive fluorescence assay system. The b-aryl ether cleavage enzyme was produced by a newly isolated fungus 2BW-1 and is secreted into the extracellular fraction. The b-aryl ether cleavage enzyme converts the guaiacylglycerol b-O-guaiacyl ether GOG to guaiacylglycerol and guaiacol. It requires the Ca alcohol structure and p-hydroxyl group and specifically attacks the b-aryl ether linkage of high-molecular mass lignins with addition of two water molecules at the Ca and Cb positions. Keywords lignin biodegradaion b-aryl ether linkage fungi guaiacylglycerol b-O-guaiacyl ether extracellular enzyme. Lignins are the most abundant high-molecular mass aromatic compounds in plants. In trees high levels of lignin are synthesized in wood and account for 15-36 of the dry weight of wood. Lignins are complex phenolic polymers that reinforce the walls of certain cells in the vascular tissues of higher plants. Lignin plays an .
