Valorizing wheat straw via TsOH/EG pretreatment: co-production of ethanol, furfural, and lignin-based surfactant.

Developing an environmentally friendly and efficient pretreatment method to achieve full-component utilization of biomass components (cellulose, hemicellulose, and lignin) is essential for sustainable biorefining. The TsOH/EG system was applied to simultaneously fractionate the three major constituents, yielding excellent cellulose preservation along with high removal efficiencies for hemicellulose and lignin. Under optimal conditions (2.5 % TsOH (w/w), EG: H2O = 60:40 (v/v), 160 °C, 30 min), cellulose retention reached 90.99 %, with complete hemicellulose removal (100 %) and 60.59 % lignin removal achieved. Concurrently, the one-pot catalytic dehydration of hemicellulose yielded 31.44 % furfural. Lignin recovered from the pretreatment liquor via acid precipitation was recycled as the surfactant (LBS) in the fermentation process, enabling the ethanol yield to be maintained at 84.35 % even at a high solid loading of 25 % (w/v). Mass balance and energy analysis further indicate that processing 1 kg of wheat straw (WS) using the 2.5 % TsOH/EG pretreatment can generate 67.35 g furfural, 256.71 g ethanol, and 90.40 g lignin-based surfactant (LBS), achieving an energy recovery rate of 76.82 %.