| 摘要 |
<p>In some variations, the invention provides a process for producing purified cellulose, comprising: providing a feedstock comprising lignocellulosic biomass; contacting the feedstock with sulfur dioxide, water, and a solvent for lignin, to produce intermediate solids and a liquid phase comprising hemicelluloses and lignin; mildly bleaching the intermediate solids to further delignify the intermediate solids, thereby generating cellulose-rich solids; and washing the cellulose-rich solids to generate purified cellulose with less than 2 weight percent lignin. The bleaching may employ bleaching agents including lignin-modifying enzymes. The bleaching and washing steps may be combined. It is also possible to carry out bleaching prior to, or simultaneously with, biomass fractionation in the digestor, which may help reduce downstream lignin precipitation. The purified cellulose may be utilized for making cellulose materials or cellulose derivatives, or for hydrolysis to produce glucose.</p> |
