Fig. 1From: Recent advances in lignin valorization with bacterial cultures: microorganisms, metabolic pathways, and bio-productsThe basic structure and compositions of lignin units in different species. The lignin unit compositions mentioned here were quantified by 2D nuclear magnetic resonance technology [58]. H-lignin here may contain some residual 4-vinyl-phenol that comes from p-coumaric acid, which should not be included in “lignin”Back to article page