Construction of efficient and convenient saccharification system from bamboo residual resources and co-production of high-purity lignin

The efficient production of carbohydrates from lignocellulosic biomass while co-producing high-quality lignin represents a critical challenge in the full utilization of biomass. This study constructed an alkaline deep eutectic solvent (DES) fractionation system for the efficient utilization of bamboo residual resources. 91.21 % and 89.76 % retentions of glucan and xylan, and 41.75 % yield of high-quality lignin (high-quality and high-purity) were achieved at 140 ℃ for 2 h. High glucose and xylose yields of 87.23 % and 94.60 % were obtained via the enzymatic hydrolysis of pretreated bamboo. In addition, the alkaline DES showed impressive water tolerance. It remained high pretreatment efficiency even when 40 % of water was introduced in the DES system, which should be due to the improvement of the polarity and viscosity of DES. Furthermore, the alkaline DES exhibited excellent recyclability, which could provide 71.69 % delignification, 77.69 % yield of glucose, and 94.47 % yield of xylose even at the fourth pretreatment cycle without the separation of lignin and addition of fresh DES. Overall, the efficient and recyclable production of carbohydrate and a high-quality lignin system exhibited excellent potential in the high-value utilization of biomass. • An efficient and convenient saccharification and co-production of high-purity lignin system was developed. • Nitrogen-containing alkaline components not only enhance carbohydrate yield, also suppress the condensation of lignin. • The alkaline DES exhibited satisfying pretreatment performance in water and recoverability.