(748g) Dilute Alkali Flowthrough Pretreatment of Softwood

Alkali pretreatment effectively disrupts biomass plant cell wall. In this study, dilute alkali flowthrough pretreatment of softwood was investigated at 200-270 °C for 2-10 min at a flow rate of 25 mL/min, under pH of, 8, 9, 11, and 12, respectively, comparing with water flowthrough pretreatment at pH 6.4. The composition analysis of pretreated solid residues and the recovered liquid streams showed the removal profile of biomass components and the recovery profile of sugars/chemicals as a function of pretreatment severity. 2D ¹³C-¹H NMR analysis revealed that complete solubilization of biomass under high pH conditions resulted in pretreated liquid stream rich in various compounds, including monomeric and oligomeric aromatics, and carbohydrates degradation products. Results indicated that initial pH greatly affected the biomass degradation pathways and efficiency. The plausible mechanism of biomass degradation by dilute alkaline under various pretreatment severities was proposed.