Characterization of Pyrolysis Bio-Oil and Biochar from <i>Polyporus brumalis</i>-Pretreated Pine Wood Chip

In the context of the dual-carbon goal, lignocellulosic biomass has emerged as a crucial renewable energy source. However, its complex composition and high oxygen content pose challenges to the quality of pyrolysis products, which are difficult to use directly. Existing studies on the effect of Polyporus brumalis on biomass pyrolysis are scarce. This study aimed to explore the impact of P. brumalis SHBCC D61730 pretreatment on biomass structure and its pyrolysis behaviors. Pine wood chips were pretreated with the fungus for different durations. Then, thermogravimetric analysis and fixed-bed pyrolysis experiments together with some characterizations were conducted. The results showed that P. brumalis selectively degraded hemicellulose and cellulose, reducing their contents by 57.49 and 42.73%, respectively, after 5 weeks, while enriching lignin (58.66%). Pretreatment disrupted the cellulose crystalline zone and created pore structures. It also changed biomass pyrolysis characteristics, increasing biochar and bio-oil yields to 33.25 and 51.93%, respectively, and decreasing gas yield. Bio-oil was enriched in certain saccharides, including 1,4:3,6-dianhydro-.alpha.-d-glucopyranose and 1,6-anhydro-β-d-glucopyranose. The BET surface area of biochar first increased and then decreased with pretreatment time, reaching a maximum of 162.81 m2/g at 3 weeks pretreatment. This research provides a scientific basis for the high-value utilization of biomass resources.