Mild and recyclable ethylenediamine pretreatment for bacterial cellulose fermentation and lignin valorization

Abstract

In this study, a novel mild and recyclable ethylenediamine (EDA) pretreatment method was developed. This pretreatment process efficiently eliminated lignin and facilitated the recovery of pretreatment reagents. Under optimized conditions at 70 °C, more than half of lignin was removed from the corn stover (CS). Consequently, the enzymatic hydrolysis of glucose and xylose achieved yields of 82.1% and 50.4%, respectively. Notably, the recovered EDA was efficiently reused and maintained comparable pretreatment efficiency even after five rounds of recovery. The pretreated CS was effectively used for bacterial cellulose fermentation without requiring additional detoxification steps. Furthermore, the analysis of EDA lignin (EL) revealed the presence of numerous amino groups introduced into the lignin structure. Subsequently, EL was used in the polyurethane (PU) foam preparation. The results revealed that EL-based PU foam featured higher compressive strength, density, thermal stability, and adsorption capacity for dyes and heavy metal ions compared with alkali lignin-based PU foam.