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Abstract Volatile organic compounds (VOCs) are by‐products of cadaveric decomposition and are responsible for the odor associated with decomposing remains. The direct link betweenVOCproduction and individual postmortem microbes has not been well characterized experimentally. The purpose of this study was to profileVOCs released from three postmortem bacterial isolates (Bacillus subtilis, Ignatzschineria indica, I. ureiclastica)using solid‐phase microextraction arrow (SPMEArrow) and gas chromatography–mass spectrometry (GC‐MS). Species were inoculated in headspace vials on Standard Nutrient Agar and monitored over 5 days at 24°C. Each species exhibited a differentVOCprofile that included common decompositionVOCs.VOCs exhibited upward or downward temporal trends over time.Ignatzschineria indicaproduced a large amount of dimethyldisulfide. Other compounds of interest included alcohols, aldehydes, aromatics, and ketones. This provides foundational data to link decomposition odor with specific postmortem microbes to improve understanding of underlying mechanisms for decompositionVOCproduction.
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Volatile organic compounds produced during postmortem processes can be linked via chromatographic profiles to individual postmortem bacterial species
Decomposition odor is produced during postmortem mammalian tissue breakdown by bacteria, insects, and intrinsic chemical processes. Past research has not thoroughly investigated which volatile organic compounds (VOCs) can be linked directly to individual bacterial species on decomposing remains. The purpose of this study was to profile the VOCs produced over time by individual species of bacteria using comprehensive two- dimensional gas chromatography (GC×GC) to expand our foundational knowledge of what each bacterial species contributes to decomposition odor. Five different species of bacteria (Bacillus subtilis, Ignatzschineria indica, Ignatzschineria ureiclastica, Curtobacterium luteum, and Vagococcus lutrae) were cultured on standard nutrient agar individually and monitored daily using solid phase microextraction arrow (SPME Arrow) and GC×GC in combination with quadrupole mass spectrometry (qMS) and flame ionization detection (FID). The GC×GC-qMS/FID approach was used to generate rich VOC profiles that represented the bacterial species’ metabolic VOC pro duction longitudinally. The data obtained from the chromatographic output was used to compare with a prior study using one-dimensional GC-qMS, and also between each of the five species to investigate the extent of overlap between species. No single VOC could be found in all five bacterial species investigated, and there was little overlap in the profile between species. To further visualize these differences, chromatographic peak data was investigated using two different ordination strategies, principal component analysis (PCA) and principal coordinate analysis (PCoA). The two ordination strategies were compared with each other using a Procrustes analysis. This was performed to understand differences in ordination strategies between the separation science community and chemical ecological community. Overall, ordination strategies were found to produce similar results, as evidenced by the correlation of PCA and PCoA in the Procrustes analysis. All analysis strategies yielded distinct VOC profiles for each species. Further study of additional species will support understanding of the holistic view of decomposition odor from a chemical ecology perspective, and further support our understanding of the production of decomposition odor that culminates from such a complex environment.
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- Award ID(s):
- 2346598
- PAR ID:
- 10527967
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Journal of Chromatography A
- Volume:
- 1728
- ISSN:
- 0021-9673
- Page Range / eLocation ID:
- 465017
- Subject(s) / Keyword(s):
- Forensic taphonomy Decomposition odor Postmortem microbiology GC×GC Forensic chemometrics Ordination
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.chroma.2024.465017
