Bio-based platform chemicals synthesized from lignin biorefinery

Bio-based chemicals synthesized by lignin offer a promising pathway of bioenergy utilization to achieve the target of the Paris Agreement with <2 degree celsius of climate warming temperature. Recently, numerous efforts have been made in lignin biorefinery, including lignin extraction, separation, depolymerization and product separation, among which each subprocess has a profound effect on the overall process. The right configuration and integration implementation of biorefinery subprocesses determine the ultimate efficiency and cost. This review provides an in-depth mechanism of understanding subprocesses aiming to provide insight into the right configurations and integration implementation of subprocesses and early commercialization of lignin biorefinery. This review includes (1) elucidation of the lignin biosynthesis pathway, (2) dissection of the mechanism of biorefinery subprocesses with intelligible graphical overviews and summary, (3) analysis of tech-economic viability from the view of market potential and each biorefinery subprocess, and (4) discussion of challenge and perspective with the emphasis on gene engineering and start-up time of lignin-based bioenergy popularization. The current results indicate that more efforts should be made toward the gene engineering regulation and integration implementation of subprocesses to promote the early commercialization of lignin biorefinery considering that the delayed use of bioenergy may reduce carbon emission mitigation capacity and increase global food risk.