Develop Biological Systems for Lignocellulose Conversion

摘要

Specific tasks were conducted to investigate the optimization of lignin decomposition by Phanerochaete chrysosporium in thermomechanical pulps in solid substrate fermentations and the bleaching of kraft pulp by ligninolytic fungi. Development of a continuous assay method for the measurement of enzymatic defibrillation of cellulose and the purification and characterization of C. thermocellum cellulase were also pursued. Results of studies on the influence of selected factors on the degradation by Phanerochaete chrysosporium of lignin in thermomechanical pulp are described. In the solid substrate fermentations, as well as in liquid fermentations, a suppressive effect of added nutrient nitrogen was observed. Elimination of this nitrogen repression should greatly accelerate the rate of lignin metabolism and is the focus of continuing research. Research established that unbleached kraft pulp is partially delignified (bleached) on incubation under specified conditions with ligninolytic fungi. This decreases the requirements for bleaching chemicals, and has potential for reducing pollution due to byproducts or current chemical bleaching.