Figure 2. Expanded aliphatic oxygenated (δC/δH 50-110/2.5-6.0, top) and aromatic (δC/δH 100-125/6.0-8.0, bottom) regions of the 2D-HSQC NMR spectra of paulownia samples; Control without enzyme (a, d), treated with 50 U g-1 enzyme (b, e) and treated with 50 U g-1 enzyme and 3% MeS. The lignin and carbohydrate signal assignments are listed in Table 2 and the lignin structures identified are depicted in Figure 3. Correlation signals of MeS in the HSQC spectrum from laccase-mediator treated paulownia are observed at δC/δH 52.1/3.82 (C/H in MeS) and δC/δH 106.4/7.20 (C2/H2 and C6/H6 in the aromatic ring).
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