Table 2 Semiquantitative ¹H-¹³C HSQC NMR structural characterization of untreated and 7 days P. anserina-treated wheat straw lignin

Lignin subunits (%)^a

 H

4

4

 G

61

59

 G_ox

0

2

 S

35

34

 S_ox

0

2

  S/G

0.6

0.6

Hydroxycinnamates (%)^b

 p-Coumarate

8

6

 Ferulate

10

8

Flavonolignin (%)^b

 Tricin

14

15

Lignin interunit linkages (%)^b,c

 β-O-4′ Aryl ethers

63 (93)

59 (92)

 β-5′ Phenylcoumarans

4 (5)

4 (6)

 β-β’ Resinols

1 (2)

1 (2)

Total

68 (100)

64 (100)