Enhancement of Lignin Biopolymer Isolation from Hybrid Poplar by Organosolv Pretreatments

Table 3

Structural characteristics (lignin interunit linkages and ratio) from integration of ¹³C-¹H correlation peaks in the HSQC spectra of the lignin fractions from hybrid poplar.

Linkage relative abundance (%)	MOL	EOL	POL	BOL
-Aryl-ether units (-O-4′, A)	60.7	70.6	66.7	65.4
Resinols substructures (-, B)	31.7	24.0	28.3	27.7
Phenylcoumarans substructures (-, C)	7.6	5.4	5.0	6.9
ratio	3.09	3.46	2.54	2.76