Submitted to: American Society of Agronomy
Publication Type: Abstract Only
Publication Acceptance Date: November 3, 1995
Publication Date: N/A
Technical Abstract: The effect of lignin composition on fiber degradation was assessed using cell walls isolated from cell suspensions of maize (Zea mays L.). Nonlignified walls containing bound peroxidase were synthetically lignified with several types of lignin precursors and hydrogen peroxide to a Klason lignin concentration of about 140 mg/g. Fungal hydrolase degradability of walls lignified with coniferyl aldehyde was only two-thirds that of walls lignified with p-coumaryl, coniferyl, or sinapyl alcohols. Selective reduction of aldehydes with borohydride largely eliminated degradability differences, suggesting that the high hydrophobicity of aldehyde containing lignins reduced wall degradability. Our results indicate that incorporation of p-hydroxycinnamyl aldehydes into lignin, via downregulation of cinnamyl alcohol dehydrogenase, will severely restrict the bioconversion of structural carbohydrates into ethanol fuels and into metabolizable energy for livestock.