Biphasic pretreatment excels over conventional sulfuric acid in pinewood biorefinery: An environmental analysis

This study assesses the environmental impact of pine chip-based biorefinery processes, focusing on bioethanol, xylonic acid, and lignin production. A cradle-to-gate Life Cycle Assessment (LCA) is employed, comparing a novel biphasic pretreatment method (TsOH/pentanol, Sc-1) with conventional sulfuric acid pretreatment (H2SO4, Sc-2). The analysis spans biomass handling, pretreatment, enzymatic hydrolysis, yeast fermentation, and distillation. Sc-1 yielded an environmental impact of 1.45E+01 kPt, predominantly affecting human health (96.55 %), followed by ecosystems (3.07 %) and resources (0.38 %). Bioethanol, xylonic acid, and lignin contributed 32.61 %, 29.28 %, and 38.11 % to the total environmental burdens, respectively. Sc-2 resulted in an environmental burden of 1.64E+01 kPt, with a primary impact on human health (96.56 %) and smaller roles for ecosystems (3.07 %) and resources (0.38 %). Bioethanol, xylonic acid, and lignin contributed differently at 22.59 %, 12.5 %, and 64.91 %, respectively. Electricity generation was predominant in both scenarios, accounting for 99.05 % of the environmental impact, primarily driven by its extensive usage in biomass handling and pretreatment processes. Sc-1 demonstrated a 13.05 % lower environmental impact than Sc-2 due to decreased electricity consumption and increased bioethanol and xylonic acid outputs. This study highlights the pivotal role of pretreatment methods in wood-based biorefineries and underscores the urgency of sustainable alternatives like TsOH/pentanol. Additionally, adopting greener electricity generation, advanced technologies, and process optimization are crucial for reducing the environmental footprint of waste-based biorefineries while preserving valuable bioproduct production.