Chemolytic and solid-state spectroscopic evaluation of organic matter transformation during vermicomposting of sugar industry wastes

The molecular structure of humic acid (HA) extracted was investigated by FT-IR and 13C CP/MAS NMR spectroscopy during the vermicomposting of sugar industry wastes, viz. pressmud, trash and bagasse for 60 days. A rapid decrease in C/N and lignocellulosic (lignin, cellulose, hemicellulose) content was observed in vermicompost during early phase of the process. The FT-IR and 13C CP/MAS NMR spectra of HA indicated a high rate of change in structure with increase in the alkyl C/O-alkyl C ratio during the process. Aromatic structures and carboxyl groups showed an initial increase but decreased after ∼40 days indicating extensive mineralization during final stages of vermicomposting.