Direct Extraction of Uniform Lignin Microspheres from Bamboo Using a Polyol-Based Deep Eutectic Solvent
Jinyuan Cheng, Chen Huang, Xuze Liu, Xuelian Zhou, Yunni Zhan, Tingjun Chen, Caoxing Huang, Xianzhi Meng, Guigan Fang, Arthur J. Ragauskas
Abstract
Conventional preparation of lignin micro-/nano-particles (LMNPs) often needs multiple steps accompanied by high cost, low efficiency, and low yield. Herein, this study established a polyhydric alcohol-based deep eutectic solvent (PA-DES) fractionation for direct LMNP assembly from raw lignocellulose. The results indicated that lignin was significantly extracted by 41.55–70.33% depending on the PA-DES varieties. With lignin removal, the substrate showed high glucan enzymatic saccharification from 70.44 to 100%. Specially, over 90% lignin could be recovered in each PA-DES, and the obtained LMNPs showed quite uniform spherical morphology with a tunable size of 550–3254 nm and narrow polydispersity index (PDI) of 0.295–0.398. The proposed DES showed a near theoretical recovery yield, which still featured excellent fractionation performance even after three cycles of reuse. The findings highlight the simultaneous utilization of cellulose and lignin in a one-pot biomass fractionation under mild conditions with sugars and LMNPs as the coproducts.