Table 1. Semiquantitative HSQC NMR Structural Characterization of Lignin Isolates of Residual Wheat Straw during Growth of C. subvermispora.
| free
(weeks) |
bound
(weeks) |
|||||||
|---|---|---|---|---|---|---|---|---|
| 0 | 1 | 3 | 7 | 0 | 1 | 3 | 7 | |
| lignin subunits (%)a | ||||||||
| H | 3 | 3 | 3 | 2 | 3 | 3 | 3 | 3 |
| G | 59 | 60 | 55 | 55 | 57 | 56 | 57 | 62 |
| Gox | 0 | 1 | 6 | 11 | 0 | 1 | 2 | 4 |
| S | 35 | 33 | 28 | 23 | 40 | 38 | 33 | 28 |
| Sox | 3 | 3 | 7 | 9 | 1 | 2 | 5 | 4 |
| S/G | 0.6 | 0.6 | 0.6 | 0.5 | 0.7 | 0.7 | 0.6 | 0.5 |
| hydroxycinnamates (%)b | ||||||||
| p-coumarate | 10 | 9 | 11 | 13 | 5 | 5 | 4 | 4 |
| ferulate | 5 | 5 | 6 | 4 | 5 | 6 | 6 | 6 |
| flavonolignin (%)b | ||||||||
| tricin | 13 | 12 | 14 | 15 | 6 | 6 | 7 | 9 |
a
Relative distribution of lignin subunits (H + G + Gox + S + Sox =100).
b
Relative volume integral of substructure versus volume integral of total lignin subunits.