The insoluble fiber of lignocellulosic materials including cellulose, hemicellulose, and lignin as the major components is measured as neutral detergent fiber (NDF). The fraction of undigestible components, usually cellulose fiber coated with
lignin is measured as acid detergent fiber (ADF) [21]. When ADF is treated with sulfuric acid, cellulose dissolves, leaving a residue designated acid detergent lignin (ADL) [22]. NDF, ADF and ADL are widely used to estimate the composition of lignocellulose.The contents of NDF, ADF ADL were determined according to the procedures of Goering and Van Soest [23]. The hemicellulose content was estimated by the difference between NDF and ADF, and the cellulose content was calculated based on the difference between ADF and ADL [21,24,25]. The component degradation ratio
was calculated on the basis of the total component weight loss after pretreatment. All experiments were performed in triplicate, and average values were reported,together with their span.