Cascading Fractionation of Sugarcane Bagasse Via a Novel Bio-Based Organic Amine Solvent Mediated Green Chemical Process Without Liquid Waste Emission

Abstract

Developing renewable, biodegradable, and low-toxicity bio-based organic solvent systems remains a significant challenge. In this study, two solvent systems ethanolamine-aqueous (EA-H2O) and ethanolamine-potassium hydroxide (EA-KOH) were constructed to investigate their effects on the solid recovery, cell wall components, and polymers extraction in sugarcane bagasse. Additionally, the feasibility of using the organic waste liquid generated during lignocellulose fractionation process as a liquid fertilizer was evaluated. Under optimal conditions combining 20% (v/v) EA and 1% (w/v) KOH at 70 °C for 3 hours, 77.1% of lignin and 21.8% of hemicellulose were removed with 94.1% of cellulose retention. Due to the good biocompatibility of ethanolamine, the optimal pretreated residue could be hydrolyzed by enzyme without washing and achieved 82.3% glucose yield and 78.2% xylose yield. The EA-KOH pretreatment enhances enzymatic hydrolysis efficiency by removing lignin and boosting cellulose accessibility. The recovered lignin is uncondensed and homogeneous with low molecular weight. Furthermore, the liquid waste resulting from lignin recovery stimulates rice seedling growth by boosting biomass yield and photosynthetic pigments content. Hence, this eco-friendly and low-toxicity EA-KOH system allows for the complete utilization of all components in sugarcane bagasse, achieving zero waste discharge and maximizing value.

Keywords: Ethanolamine, Lignocellulose fractionation, Enzymatic hydrolysis, Full-component utilization, Zero liquid-waste discharge