Wednesday, May 2, 2007 - 8:40 AM

The effect of hydrothermal pre-treatment of wheat straw: Microscopic investigations

Jan B. Kristensen1, Claus Felby1, Henning Jørgensen1, Lisbeth G. Thygensen1, and Thomas Elder2. (1) Danish Center for Forest and Landscape, Faculty of Life Sciences, Copenhagen University, Rolighedsvej 23, DK-1958 Frederiksberg C, Denmark, (2) Utilization of Southern Forest Products, USDA-Forest Service, Southern Research Station, 2500 Shreveport Highway, Pineville, LA 71360

Pre-treatment of biomass is an essential step in production of second generation bioethanol. Recent results indicate that only a mild pre-treatment is necessary in an industrial, economically feasible system.
The IBUS (Integrated Biomass Utilisation System) hydrothermal pre-treatment process has been shown to be effective in preparing wheat straw for enzymatic hydrolysis without the application of additional chemicals.
The effect of the pre-treatment on the straw cell wall matrix and its components has been characterised topographically by atomic force microscopy (AFM). The findings have been related to the degradability of the biomass as well as physical measurements of the pre-treated fibres (FT-IR). The altered lignin distribution in the cell wall as seen with AFM was further characterised by fluorescence confocal laser scanning microscopy.
Results suggest that the pre-treatment does not degrade the fibrillar structure of cellulose but is important for lignin re-localisation. The findings have also been compared to wheat straw pre-treated by conventional steam explosion.