Fig. 4. Nitrogen-15-CPMAS NMR spectra of insoluble residues formed from 0.4 mM 2,4,6-¹⁵N TNT within six days incubation under anaerobic/aerobic conditions in the presence of anaerobic microorganisms, laccase, and (A) 40 mM catechol and (B) 100 ppm humic acid, respectively (Samples V and VI). Upper scale referenced to NH₃, lower scale referenced to CH₃NO₂.