DEHYDROGENATION POLYMER-CELL WALL COMPLEXES AS A MODEL FOR LIGNIFIED GRASS WALLS

p-Hydroxycinnamyl alcohols were efficiently polymerized into maize wal ls by wall-bound peroxidases and in vitro generated hydrogen peroxide to produce dehydrogenation polymer-cell wall (DHP-CW) complexes. Elect ron microscopy of KMnO4-stained sections revealed that DHPs were distr ibuted throughout the cell wall matrix. DHP-CW complexes were structur ally similar to natural grass lignins according to pyrolysis, thioacid olysis, and C-13-NMR spectroscopy. Nonlignified walls were rapidly deg raded by rumen microorganisms and by commercial fungal hydrolases, whe reas DHP-CW complexes had a reduced rate and extent of degradation. Th is system is useful for modeling matrix interactions in lignified wall s and for identifying means of improving the utilization of lignocellu losic materials for nutritional and industrial purposes.