Comparative Study of Hemicelluloses Isolated with Alkaline Peroxide from Lignocellulosic Materials

Abstract

Treatment of dewaxed oil palm frond fiber; fast‐growing poplar wood; maize stems; and barley, wheat, rice, and rye straws with 2.0% H₂O₂ at pH 11.6 for 16 hr at 45°C solubilized 85.7%, 49.5%, 78.2%, 79.7%, 87.1%, 92.7%, and 79.4% of the original hemicelluloses and 72.1%, 24.9%, 87.3%, 70.9%, 85.7%, 88.6%, and 89.8% of the original lignin, respectively. The results indicated that hydrogen peroxide at pH 11.6 had a significant effect on the release of hemicelluloses and delignification from oil palm frond fiber and cereal straws such as maize stems and barley, wheat, rice, and rye straws under the condition used. All the hemicellulosic preparations were much lighter in color and had relatively lower amounts of associated lignin than those obtained using traditional alkaline extraction in the absence of peroxide from the corresponding lignified materials. Xylose is the dominant sugar component in the hemicellulosic preparations isolated from oil palm frond fiber, fast‐growing poplar wood, maize stems, and barley, wheat and rye straws, whereas the hemicelluloses obtained from rice straw are rich in glucose and xylose. The seven hemicellulosic samples were also studied by fourier transform infrared (FT‐IR} and ¹H‐ and ¹³C‐nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), and thermal analysis.

Keywords:

• Alkaline peroxide
• Hemicelluloses
• Lignin
• Xylose

Acknowledgments

The authors are grateful for the financial support of this research from National Natural Science Foundation of China (Nos. 30271061 and 30025036) and Guangdon Natural Science Foundation (Nos. 013034 and 36567).