Monday, April 30, 2007

An alternative application to the Portuguese agro-industrial residue: Wheat straw

Denise S. Ruzene1, Daniel P. Silva1, António A. Vicente1, Adilson R. Gonçalves2, and José A. Teixeira1. (1) Department of Biological Engineering, University of Minho, School of Engineering, Campus de Gualtar, Braga, 4710-057, Portugal, (2) Biotechnology Department, Engineering School of Lorena- EEL-USP, Rodovia Itajubá - Lorena - Km 74,5 - Bairro Campinho, Lorena-SP, Brazil

In recent years, there has been an increasing trend towards more efficient utilization of agro-industrial residues. Several processes have been developed aiming at the use of these residues, lignocellulosic materials, as raw materials in the attainment of value-added products. In paper industries, it has been demonstrated that the addition of hemicelluloses as additive in the cellulosic pulp can improve some mechanical properties of the paper or others features of papermaking. The aim of this work is to evaluate hemicellulose extraction processes in order to make possible the use of this hemicellulose as additive in the papermaking, always keeping in mind the use of the others lignocellulosic fractions (cellulose and lignin) in future applications. This procedure will lead to an attractive possibility of integral use of lignocellulosic materials in different biotechnological processes. Recent studies have shown that the extraction of hemicellulose of agro-industrial residues as sugarcane bagasse has been enhanced by treatment with distilled water in a sequential process. In this study, wheat straw samples previously milled or cut were treated initially with distilled water at 55 and 90ºC for 2 h under constant stirring, and successively treated with NaOH 5% (w/v) into a closed vessel at 90ºC for 2 h. The preliminary results show that by using ethanol, the hemicellulose fraction can be separated and precipitated. Although being a preliminary study, these results suggest the potential of this process to hemicellulose extraction, making possible its biotechnological applications. [Acknowledgements: FCT, FAPESP, CNPq, CAPES]

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