IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
Appl Biochem Biotechnol. 2011 Jul;164(5):629-41. doi: 10.1007/s12010-011-9163-9. Epub 2011 Jan 28.
The present work describes the delignification of wheat straw through an environmentally friendly process resulting from sequential application of autohydrolysis and organosolv processes. Wheat straw autohydrolysis was performed at 180°C during 30 min with a liquid-solid ratio of 10 (v/w); under these conditions, a solubilization of 44% of the original xylan, with 78% of sugars as xylooligosaccharides of the sum of sugars solubilized in the autohydrolysis liquors generated by the hemicellulose fraction hydrolysis. The corresponding solid fraction enrichment with 63.7% of glucan and 7.55% of residual xylan was treated with a 40% ethanol and 0.1% NaOH aqueous solution at a liquid-solid ratio of 10 (v/w), with the best results obtained at 180°C during 20 min. The highest lignin recovery, measured by acid precipitation of the extracted lignin, was 3.25 g/100 ml. The lignin obtained by precipitation was characterized by FTIR, and the crystallinity indexes from the native cellulose, the cellulose recovered after autohydrolysis, and the cellulose obtained after applying the organosolv process were obtained by X-ray diffraction, returning values of 21.32%, 55.17%, and 53.59%, respectively. Visualization of the fibers was done for all the processing steps using scanning electron microscopy.
本工作描述了通过顺序应用自水解和有机溶剂处理工艺实现的环保方法对麦草进行脱木质素。在 180°C 下进行 30 分钟的麦草自水解，液固比为 10（v/w）；在此条件下，44%的原木聚糖溶解，78%的糖为半纤维素水解生成的自水解液中的木二糖，总糖的 78%。相应的固体部分用 40%乙醇和 0.1%NaOH 水溶液在液固比为 10（v/w）下处理，在 180°C 下 20 分钟时效果最佳。通过酸沉淀提取的木质素来测量木质素的最大回收率为 3.25g/100ml。通过沉淀得到的木质素用傅里叶变换红外光谱（FTIR）进行了表征，并用 X 射线衍射得到了天然纤维素、自水解后回收的纤维素和应用有机溶剂处理后获得的纤维素的结晶度指数，分别为 21.32%、55.17%和 53.59%。用扫描电子显微镜对所有处理步骤的纤维进行了可视化。
