SOFTWOODS HEMICELLULOSES: IMPACT OF THE EXTRACTION CONDITIONS AND WOOD SPECIES ON THEIR CHEMICAL COMPOSITION
The effect of extraction conditions of two softwoods, spruce (Picea abies) and maritime pine (Pinus pinaster Ait.) on the quality of recovered hemicellulose fraction is reported. Different aqueous extraction liquors were used in acidic (sulfuric or acetic), water (near-neutral) and alkaline conditions (soda, soda-AQ or soda-peroxide). Depending on the extraction conditions and on the softwood species, hemicelluloses having very different chemical composition can be obtained. In acidic or nearneutral conditions, galactoglucomannans-rich fractions are obtained. However, the distribution of the monosugars is completely different between the two softwoods. Under these conditions, spruce hemicelluloses are composed of 50 to 60％ of mannans, while those obtained from maritime pine are very rich in galactans (up to 85％). When acetic acid is used, an important contamination with residual lignin is observed for some samples, because its lignin solvation ability. Temperature does not affect the balance between galactoglucomannans and arabinoxylans, but long extractions decrease the selectivity. Contrarily, the fractions obtained in alkaline conditions are mixtures of arabinoxylans and galactoglucomanns. The fractions obtained from spruce present higher proportions of arabinoxylans (up to 55％), but are importantly contaminated with residual lignin (up to 18％). For maritime pine, galactoglucomnanns is majority (up to 60％), being essentially composed of galactoses. The addition of anthraquinone or hydrogen peroxide does not impact the chemical composition of the hemicelluloses. Finally, high temperatures and long extraction times favor increasing the proportion of arabinoxylans, while decreasing the presence of residual lignin in the mixture.
hemicelluloses extraction softwoods galactoglucomannans arabinoxylans residual lignin
Denilson da Silva Perez Audrey Guillemain Arthur Janodet Adrian Soranzo Matthieu Schelcher Patrick Huber Michel.Petit-Conil
FCBA, NMA InTechFibres, Domaine Universitaire,BP 251, 38044 Grenoble, France CTP - Centre Technique du Papier FCBA, UST5 InTechFibres, Domaine Universitaire, BP 251, 38044 Greno FCBA, NMA InTechFibres, Domaine Universitaire,BP 251, 38044 Grenoble, France CTP - Centre Technique
国际会议
16th International Symposium on Wood,Fiber and Pulping Chemistry(第十六届木材、纤维及制浆化学国际会议)
天津
英文
1067-1072
2011-06-08（万方平台首次上网日期，不代表论文的发表时间）