Figure 3.

Heteronuclear single quantum correlation nuclear magnetic resonance spectra of cellulolytic enzyme lignins isolated from eucalypt wood samples. (A) Initial eucalypt sample, (B) control without enzyme, (C) sample treated with laccase alone (50 U · g^-1) and (D) sample treated with laccase (50 U · g^-1) and methyl syringate (3%). See Table 3 for lignin signal assignment, Figure 2 for the main lignin structures identified, and Table 5 for quantification of these lignin structures identified. The 52/3.8 ppm signal corresponds to some methyl syringate incorporated onto the lignin. The enzymatic pretreatment included four laccase-mediator treatments, each followed by an alkaline extraction step.