Mass Spectrometric Approaches to the Study of Bacterial Metabolomes Aimed at Diagnosis of Anaerobic Hydrocarbon Degradation and Associated Biocorrosion

摘要

Between 1,000 and 2,000 compounds were detected in most degraded ULSD samples using the Molecular Feature Extraction algorithm of the MassHunter data analysis software (Agilent). Owing the internal mass calibration during each mass scan, the mass error was below 5 ppm, which enabled nearly unambiguous molecular formula assignments. After filtering out compounds that were also present in the controls, approximately 170 compounds were found that contained only C, H and O in their molecular formulas. In plots of LC retention time versus the number of carbon atoms, many homologous series were easily visually identified, including homologous series of different geometric isomers. These plots also served as a test for the presence of series of compounds that had been assigned erroneous formulas. The observed homologous series were, in general, consistent with known pathways for anaerobic microbial alkane degradation and, in particular, with the published pathway for anaerobic degradation of shorter alkanes by D. alkanexedens. The detected metabolites were also consistent with the measured distribution of the 11 to 22 carbon, alkane chain lengths in the ULSD sample. Future experiments are planned with isotopic-labeled substrates and laser ablation as a sample preparation method.