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Organic Matter Transformations During the Weathering Process of Spent Mushroom Substrate
Author(s) -
Chefetz Benny,
Heemst Jasper D. H.,
Chen Yona,
Romaine C. Peter,
Chorover Jon,
Rosario Rex,
Mingxin Guo,
Hatcher Patrick G.
Publication year - 2000
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2000.00472425002900020030x
Subject(s) - tetramethylammonium hydroxide , chemistry , weathering , organic matter , mass spectrometry , lignin , gas chromatography–mass spectrometry , pyrolysis–gas chromatography–mass spectrometry , decomposition , substrate (aquarium) , gas chromatography , environmental chemistry , organic chemistry , chromatography , geology , oceanography , geomorphology
The weathering process of spent mushroom substrate (SMS) was studied to better understand the chemical properties and transformations of organic matter (OM) during the process. The SMS was piled (20 m by 6 m row of 1.5 m height) in an open field and weathered during 15 mo. Chemical properties of the OM collected from the top and bottom parts of the weathering pile were studied using 13 C‐nuclear magnetic resonance (NMR), tetramethylammonium hydroxide (TMAH) thermochemolysis‐gas chromatograph/mass spectrometry (GC/MS), and pyrolysis‐gas chromatograph/mass spectrometry (Py‐GC/MS). The 13 C‐NMR data suggested that weathered SMS from the top part of the pile degraded rapidly: the relative level of polysaccharides decreased by 33% while the level of aromatic C increased by 21% during the process. The TMAH thermochemolysis chromatogram exhibited peaks of methylated derivatives of phenyl, guaiacyl and syringyl structures as well as some fatty acid methyl esters. Lignin‐derived products from TMAH thermochemolysis indicate that preferential degradation of syringyl units and oxidation of Cα‐Cβ bonds occurred in the SMS from the top part of the pile. In contrast, no major changes in lignin‐derived structures were observed in the weathered SMS from the bottom part of the pile. The 13 C‐NMR, Py‐GC/MS and TMAH thermochemolysis‐GC/MS analyses indicated that the SMS decomposed rapidly at the top part of the weathering pile, whereas decomposition at the bottom of the pile was significantly slower, probably due to lack of oxygen. These analyses were shown to be useful techniques for the characterization of degradation processes in SMS. Therefore, their application to studies on OM transformation and humification processes is highly recommended.