A COMPARISON OF THE INSOLUBLE RESIDUES PRODUCED BY THE KLASON LIGNIN AND ACID DETERGENT LIGNIN PROCEDURES

Two methods-Klason lignin (KL) and acid detergent lignin (ADL)-for det ermining lignin concentration in plants were compared using stem mater ial from lucerne (Medicago sativa L), cocksfoot (Dactylis glomerata L) and switchgrass (Panicum virgatum L), at three stages of maturity, an d leaf samples from lucerne and cocksfoot. For all forages, KL values were higher than ADL values. Lucerne samples, which had crude protein levels twice that of the grass species, had KL values that were only 3 0-40% higher than ADL values; in grasses, KL values were 200-300% grea ter than ADL values. The addition of nitrogenous materials (bovine ser um albumin, lysine, and ammonium sulfate) to commercial xylan and cell ulose did not result in additional KL residue. Pyrolysis-GC-MS reveale d that both residues appeared to be similar to the orginal plant ligni n and did not appear to be contaminated with carbohydrate or protein. The higher values for grass KL residues were not due to protein contam ination or incomplete hydrolysis of carbohydrates, but were more likel y due to the solubilization of lignin components by the ADL treatment. KL values may give a more accurate quantification of the total lignin within forage plants.