Quality carbon fibers from fractionated lignin

A strategy was developed to produce quality carbon fibers from industrial waste lignin. The strategy employs an enzyme-mediator system to efficiently fractionate lignin into soluble and insoluble fractions, where the latter serves as a superior carbon fiber precursor. Mechanistic studies revealed that higher MW, less hydroxy groups, and more β-<italic>O</italic>-4 linkages improve the spinnability, crystallization, and mechanical performance of carbon fibers.