Figure 4

HSQC NMR spectra of raw and pretreated cellulolytic enzyme lignin in the aliphatic region: (a) raw; (b) 20 mL/min, 140°C, 12 min; (c) 20 mL/min, 140°C, 192 min; (d) 20 mL/min, 180°C, 12 min; (e) 20 mL/min, 180°C, 192 min; (f) 0 mL/min, 140°C, 192 min; (g) 0 mL/min, 180°C, 12 min. Identified units include methoxy groups, β-O-4 ethers (A_α, A_β, A_γ), β-5/α-O-4 phenyl-coumararan (B_α, B_β, B_γ), and spirodienone (C_α) units. Signal assignments are presented in Table 4.