Isolation of soil lignins by combination of ball-milling and cellulolysis: Evaluation of purity and isolation efficiency with pyrolysis/GC/MS

Abstract CuO oxidation is traditionally used for soil lignin study, although, like other degradation methods it might give access only to a part of the lignin polymers. For structural characterization, lignins are conventionally isolated from plant material by combining ball-milling, cellulolysis and solvent extraction to recover a milled wall enzymatic lignin (MWEL) fraction. This method might isolate condensed lignins, which are not accounted for CuO oxidation. MWELs are still associated with polysaccharides. This study aimed to evaluate if the MWEL method can be used complementary to CuO oxidation for soil lignin studies. We assessed the purity of isolated lignins by pyrolytic characteri…