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 structur es by chemical analysis and of the cell wall ultrastructure by transmission electron microscopy. While distinct chemical changes in the target polymer s were observed when each system was used separately, a combination of the two types of catalysts did not significantly increase either lignin oxidati on or hemicellulose hydrolysis. Microscopic observations however revealed t hat the supramolecular organization of the cell wall polymers was significa ntly altered. This suggests that the abiotic Mn-oxalate complex and the xyl anase 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.