Degradation of Biomacromolecules during High-Rate Composting of Wheat Straw–Amended Feces
- A. H. M. Veeken *a,
- F. Adanid,
- K. G. J. Nieropb,
- P. A. de Jagerc and
- H. V. M. Hamelersa
- a Dep. of Environmental Technology, Wageningen Agricultural Univ., P.O. Box 8129, 6700 EV Wageningen, the Netherlands
d Dipartimento di Fisiologia delle Piante Coltivate e Chimica Agraria, Univ. of Milan, Via Celoria 2, 20133 Milano, Italy
b Lab. of Soil Science and Geology, Wageningen Agricultural Univ., P.O. Box 8129, 6700 EV Wageningen, the Netherlands
c Lab. of Molecular Physics, Wageningen Agricultural Univ., P.O. Box 8129, 6700 EV Wageningen, the Netherlands
Pig (Sus scrofa) feces, separately collected and amended with wheat straw, was composted in a tunnel reactor connected with a cooler. The composting process was monitored for 4 wk and the degradation of organic matter was studied by two chemical extraction methods, 13C cross polarization magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) and pyrolysis gas chromatography–mass spectrometry (GC–MS). Wet-chemical extraction methods were not adequate to study the degradation of specific organic compounds as the extraction reagents did not give selective separation of hemicellulose, cellulose, proteins, and lignins. A new method was proposed to calculate the contribution of four biomacromolecules (aliphatics, proteins, polysaccharides, and lignin) from the 13C CPMAS NMR spectrum. Pyrolysis GC–MS allowed identification of the composition of the biomacromolecules. The biomacromolecules showed different rates of degradation during composting. High initial degradation rates of aliphatics, hemicellulose, and proteins were observed, where aliphatics were completely degraded and hemicellulose and proteins were partly recalcitrant during the four weeks of composting. The degradation rate of cellulose was much lower and degradation was not completed within the four weeks of composting. Lignin was not degraded during the thermophilic stage of composting but started to degrade slowly during the mesophilic stage. A combination of 13C CPMAS NMR and pyrolysis GC–MS gave good qualitative and semiquantitative assessments of the degradation of biomacromolecules during composting.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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