Abiotic and enzymatic degradation of wheat straw cell wall: a biochemical and ultrastructural investigation

The action of an abiotic lignin oxidant and a diffusible xylanase on wheat straw was studied and characterized at the levels of the molecular structures by chemical analysis and of the cell wall ultrastructure by transmission electron microscopy. While distinct chemical changes in the target polymers were observed when each system was used separately, a combination of the two types of catalysts did not significantly increase either lignin oxidation or hemicellulose hydrolysis. Microscopic observations however revealed that the supramolecular organization of the cell wall polymers was significantly altered. This suggests that the abiotic Mn-oxalate complex and the xylanase cooperate in modifying the cell wall architecture, without noticeably enhancing the degradation of the constitutive polymers. (C) 2000 Elsevier Science B.V. All rights reserved.