Severe inhibition of maize wall degradation by synthetic lignins formed with coniferaldehyde
✍ Scribed by Grabber, John H; Ralph, John; Hatfield, Ronald D
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 203 KB
- Volume
- 78
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
Although the enzymatic or ruminal degradability of plants deÐcient in cinnamyl alcohol dehydrogenase (CAD) is often greater than their normal counterparts, factors responsible for these degradability di †erences have not been identiÐed. Since lignins in CAD deÐcient plants often contain elevated concentrations of aldehydes, we used a cell-wall model system to evaluate what e †ect aldehyde-containing lignins have on the hydrolysis of cell walls by fungal enzymes. Varying ratios of coniferaldehyde and coniferyl alcohol were polymerised into non-ligniÐed primary walls of maize (Zea mays L) by wall-bound peroxidase and exogenously supplied Coniferaldehyde lignins formed H 2 O 2 . fewer cross-linked structures with other wall components, but they were much more inhibitory to cell wall degradation than lignins formed with coniferyl alcohol. This suggests that the improved degradability of CAD deÐcient plants is not related to the incorporation of p-hydroxycinnamaldehyde units into lignin. Degradability di †erences were diminished if enzyme loadings were increased and if hydrophobic aldehyde groups in lignins were reduced to their corresponding alcohols by ethanolic sodium borohydride.
1998 Society of Chemical ( Industry.