Upgrading Traditional Pulp Mill into Biorefinery Platform: Wheat Straw as a Feedstock

To maximize utilization of lignocellulose, a two-stage process based on dilute acid pretreatment followed by soda-AQ post-treatment was adopted for wheat straw fractionation. The three main components of wheat straw were successfully separated and recovered, and 15.2% degraded sugars and 35.0% cellulose fibers were obtained under the optimum condition using the dilute acid pretreatment with 0.6% H2SO4 at 130 degrees C for 60 min. This was followed by 16% NaOH and 0.05% AQ at 140 degrees C for 60 min. The cellulose fiber presented a high purity (91.0%) with a crystallinity of 64.7%, and its average degree of polymerization was 997. Meanwhile, the lignin (18.4%) obtained from the new pattern of the straw pulping process showed an extremely low sugar content (0.73%) which exhibited a promising potential for further applications. Under the proposed biorefinery platform, over 80% of the three major components were recovered from straw (82.1%). These results highlight the maximum utilization of lignocellulosic biomass based on the integrated biorefinery platform, which provides a promising future to upgrade traditional pulp mill performance.