Efficient, environmentally-friendly and specific valorization of lignin: promising role of non-radical lignolytic enzymes Wenya Wang1,2 · Chao Zhang1 · Xinxiao Sun1 · Sisi Su1 · Qiang Li3 · Robert J. Linhardt4,5,6

of chemical bonds but can also catalyze the radical-based re-polymerization of lignin fragments. In contrast, nonradical lignolytic enzymes selectively cleave chemical bonds in lignin and lignin model compounds and, thus, show promise for use in the preparation of high valueadded chemicals. In this mini-review, recent developments on non-radical lignolytic enzymes are discussed. These include recently discovered non-radical lignolytic enzymes, their metabolic pathways for lignin conversion, their recent application in the lignin biorefinery, and the combination of bio-catalysts with physical/chemical methods for industrial development of the lignin refinery.