Decoding temperature and NaOH concentration effects on environmental footprints for sustainable lignocellulosic biorefining through systematic LCA

Lignocellulose-based biorefineries offer sustainable solutions to the energy crisis, but enzymatic hydrolysis remains a bottleneck. This study comprehensively compared three typical NaOH pretreatment strategies through experimental approaches and life cycle assessment (LCA). Results showed ozone depletion, GWP, smog, acidification, eutrophication, and ecotoxicity were similar across varying NaOH concentrations and temperatures. However, increasing pretreatment temperature from −15 °C to 160 °C raised terrestrial ecosystem, human health, and water resource burdens. For banana leaf biomass, optimal conditions (3% NaOH, 5% solid-liquid ratio, 50 °C, 30 min) achieved 81.75% enzymolysis efficiency with minimal environmental impacts (ecosystem: 7.726 × 10⁻⁹, human health: 3.500 × 10⁻⁶, resources: 0.094). Higher temperatures worsened climate change and fossil fuel depletion, with electricity use being the major burden contributor. Notably, the −15 °C outdoor scenario had the lowest overall impact. This study provides a systematic evaluation framework to guide the sustainable design of biomass pretreatment processes in industrial applications.