Avance 3 800us system

The purified MWLs (approx. 15 mg) were dissolved in 600 ll of dimethylsulfoxide (DMSO)-d 6 and subjected to a NMR analysis on an Avance III 800US system equipped with a cryogenically cooled 5-mm TCI gradient probe (800 MHz, Bruker Biospin, Billerica, MA, USA). The central DMSO solvent peaks (d C /d H : 39.5/2.49 ppm) were used as an internal reference. Adiabatic heteronuclear single-quantum coherence (HSQC) NMR experiments were carried out using standard implementation (''hsqcgcep.3'') with parameters described in the literature [34] . Data processing and analysis used Bruker TopSpin 3.2 software (Bruker Biospin). HSQC plots were obtained with typical matched Gaussian apodization in F2 and squared cosine-bell apodization in F1. For the integration of the lignin aromatic signals (Fig. 1a), C 2 -H 2 correlations from G units (G) and C 2 -H 2 /C 6 -H 6 correlations from S units (S), H units (H), and p-coumarate units (pCA), and C 2 0 -H 2 0/ C 6 0 -H 6 0 correlations from tricin units (T), were used, and the S, H, pCA, and T integrals were logically halved [35] (link). For the integrations of the lignin inter-monomeric linkages (Fig. 1b), well-resolved C a -H a contours from I, I 0 , II, II 0 , III, III 0 , IV and V units were integrated and the III and III 0 integrals were logically halved [34, 35] (link).