Bibliographic Details
| Title: |
Carbohydrate oxidases in ericoid and ectomycorrhizal fungi: a possible source of Fenton radicals during the degradation of lignocellulose. |
| Authors: |
Burke, R. M.1, Cairney, J. W. G.2 |
| Source: |
New Phytologist. Aug98, Vol. 139 Issue 4, p637-645. 9p. |
| Subjects: |
Mycorrhizal fungi, Fenton's reagent, Hydroxyl group, Lignocellulose, Organic compounds, Parasitic plants |
| Abstract: |
Isolates of the ericoid mycorrhizal fungus Hymenoscyphus ericae (Read) Korf et Kernan, and the ectomycorrhizal fungi Suillus variegatus (Swartz ex Fr.) and Pisolithus tinctorius (Pers.) Coker & Couch, along with a Cortinarius sp. and the white rot Phanerochaete chrysosporium Burdsall were examined for the ability to oxidize carbohydrates to their corresponding lactones and to excrete the H2O2 produced thereby. All except Phanerochaete chrysosporium were found to express cellobiose oxidase (cellobiose dehydrogenase, EC 1 . 1 . 19 . 88) and glucose oxidase (β-D-glucose : oxygen 1-oxidoreductase, EC 1 . 1 .3 . 4) when grown on cellobiose and glucose respectively. Production of extracellular H2O2 was visualized during growth on both substrates using ABTS as the chromogen. According to the Fenton reaction, H2O2 will react with hydrated or chelated Fe(II) in the environment to produce hydroxyl (Fenton) radicals, HO•. Mycelial extracts from each of the mycorrhizal fungi produced HO• in the presence of cellobiose and Fe(II), presumably mediated by H2O2 produced by cellobiose oxidase activity in the extracts. Conditions favourable to HO• production were shown to exist in Modified Melin-Norkrans medium, and the data discussed in relation to previously observed lignin degradation by mycorrhizal fungi. [ABSTRACT FROM AUTHOR] |
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| Database: |
Engineering Source |
