Intrinsic biodegradation potential of aromatic hydrocarbons in an alluvial aquifer – Potentials and limits of signature metabolite analysis and two stable isotope-based techniques

Abstract

C-labels in microcosms is that novel metabolites can be linked more easily to specific mother compounds even in complex systems. This was achieved using alluvial sediments where 13 C-acenaphthyl methylsuccinate was identified as transformation product of the anaerobic degradation of acenaphthene.

In situ detection of anaerobic alkane metabolites in subsurface environments

“…With the discovery that methylnaphthalenes and other multi-ringed aromatics (including heterocycles) can also be metabolized by fumarate addition, the corresponding succinates have also been detected in field studies (Griebler et al, 2004; Bombach et al, 2010; Jobelius et al, 2011; Morasch et al, 2011), attesting to the usefulness of this method for demonstrating the in situ anaerobic biodegradation of many hydrocarbon classes. Furthermore, primer sets based on the catabolic gene(s) encoding benzylsuccinate synthase have been developed by several investigators and have been used successfully to indicate the metabolic potential for microbial communities in contaminated field samples to anaerobically biodegrade alkylbenzenes (e.g., Beller et al, 2002, 2008; Winderl et al, 2007; Callaghan et al, 2010; Oka et al, 2011; von Netzer et al, 2013).…”

“…However, documenting that such anaerobic hydrocarbon biodegradation is occurring in fuel-contaminated sites or in fossil energy reservoirs remains a challenge. For example, multiple lines of evidence, both chemical and microbiological, are required to offer support that in situ hydrocarbon bioremediation is occurring in contaminated aquifers (NRC, 1993; Gieg and Suflita, 2005; Beller et al, 2008; Weiss and Cozzarelli, 2008; Bombach et al, 2010; Morasch et al, 2011; Jeon and Madsen, 2012). In conjunction with the elucidation of anaerobic hydrocarbon metabolic pathways, the idea of using anaerobic metabolites to indicate that in situ anaerobic hydrocarbon biodegradation is occurring emerged as a powerful tool for proving in situ bioremediation.…”

“…Thus, the fumarate addition metabolites are most diagnostic of the in situ anaerobic metabolism of specific hydrocarbons including alkanes. It should be noted, however, that there are some disadvantages to using signature metabolites as sole indicators of in situ bioremediation (Morasch et al, 2011). For example, these products may be below analytical detection limits, knowledge of biodegradation pathways for various hydrocarbons is required (e.g., in order to determine which metabolites to look for), and commercially-available authentic standards for many of the fumarate addition products are not available for analytical comparisons with metabolites found in field samples.…”

“…For example, these products may be below analytical detection limits, knowledge of biodegradation pathways for various hydrocarbons is required (e.g., in order to determine which metabolites to look for), and commercially-available authentic standards for many of the fumarate addition products are not available for analytical comparisons with metabolites found in field samples. Thus, using signature fumarate addition metabolites to determine whether in situ hydrocarbon metabolism is occurring at a given site should ideally be done in conjunction with other methods of site assessment (Bombach et al, 2010; Morasch et al, 2011). …”

Application of stable isotope tools for evaluating natural and stimulated biodegradation of organic pollutants in field studies

“…Commonly, laboratory biodegradation experiments have been conducted with 13 C-labelled pollutants in order to identify or confirm specific metabolites for their biodegradation pathways (e.g. [39]). Clear evidence of specific biodegradation pathways at contaminated sites has been provided by the detection of stable-isotope labelled metabolites derived from in situ microcosms with 13 C-labelled target compounds (e.g.…”