Wheat straw is a potential source of feedstock for biofuel production that does not compete with food. We have screened 48 wheat lines from a collection representing a broad range of the biodiversity of wild and domestic wheat. Wheat straw was fractionated into water-soluble and nonsoluble fractions. In the water-soluble fraction (WSF), we found a broad variation in the concentration of free soluble sugars (FSS) and a narrow variation in starch. The FSS fraction could reach levels of reducing sugars as high as 130 g sugar/kg of straw. The analysis of the FSS by ion chromatography indicated that fructose and glucose were the major sugar monomers in this fraction. The composition of the nonsoluble cell wall fraction was determined by both pyrolysis and direct chemical analysis. These analyses showed a limited variation in the lignin or the cellulose fraction. There was a significant degree of variation among wheat lines in the enzymatic saccharification of the straw, following acid pretreatment. Interestingly, the straw from wild wheat had the highest degree of saccharification compared to domestic lines. These findings are of interest for the biofuel industry because they mean that wheat lines can be developed in which a significant amount of free soluble sugars can be easily extracted from straw without the need for costly pretreatment and enzymatic deconstruction. Moreover, the high FSS trait might be combined with the high enzymatic saccharification trait suggesting that wheat lines can be developed with a straw composition better adapted for biofuel production.
Bibliographical noteFunding Information:
We would like to thank Prof. Moshe Feldman (Weizmann Institute of Sciences) for providing seeds of the wheat collection and for advice and Prof. Asaph Aharoni (Weizmann Institute of Sciences) for advice with the sugar composition analysis. We thank Dr. Eli Morag and Dr. Michael Loelovich (Designer Energy) for help with the cellulose hydrolysis. We thank Dr. Miron Abramson and Tali Eylat (Futuragene) for help with the cell wall component analysis. We also thank Ilan Bessudo for help with preparation of straw samples for analysis and Dr. Zvi Tamari for help with sugar composition analysis. This work was supported by a grant from the ICORE foundation, solar fuel project and by the Leona and Harry Helmsley charitable trust to A.A.L. YT was supported by the Ministry of Science and Technology, Israel.
© 2015, The Author(s).
- Free soluble sugars (FSS)
- Lignocellulosic biomass
- Water-soluble fraction (WSF)
- Wheat straw