Title
Separation of hemicelluloses from Eucalyptus species: Investigating the residue after alkaline treatment
Authors
WANXI PENG LANSHENG WANG MAKOTO OHKOSHI and MINGLONG ZHANG

Received October 28, 2013
Published Volume 49 Issue 9-10 October-December
Keywords Eucalyptus urophydis, Eucalyptus urophynis, Eucalyptus camaldulensis, hemicelluloses, separation characteristics

Abstract
Hemicellulose, the second most abundant polysaccharide in nature, is an ideal biomass for bioconversion. However, it binds with cellulose and lignin to form the cell wall and efficient separation of Eucalyptus wood biomass components remains difficult. Therefore, the residue after alkaline treatment of Eucalyptus species was investigated and analyzed by FTIR, XRD, UV and SEM. The results showed that the crystallinity index of Eucalyptus urophydis, Eucalyptus urophynis and Eucalyptus camaldulensis lignocelluloses reached respective maxima of 63.49% (6 h), 58.29% (3 h), and 60.70% (9 h) in KOH solution. However, the lignin content in these residues was reduced by 10.1%, 8.38%, and 5.7%, respectively. After the alkaline treatment, most of the acetyl groups in the residue were broken down because the alkali treatment under the conditions used mostly cleaved the ester bonds. It was found that the hemicelluloses were dissolved after 3 h, while after 20 h, the pit membrane was dissolved, pits were penetrated, holes appeared in the cell wall, and cell gaps opened.