Back to Search Start Over

Co-metabolic conversion of toluene in anaerobic n-alkane-degrading bacteria

Authors :
Friedrich Widdel
Heinz Wilkes
Johann Heider
Simon Kühner
René Jarling
Sven Lahme
Ralf Rabus
Source :
Environmental Microbiology. 13:2576-2586
Publication Year :
2011
Publisher :
Wiley, 2011.

Abstract

Summary Diverse microorganisms have been described to degrade petroleum hydrocarbons anaerobically. Strains able to utilize n-alkanes do not grow with aromatic hydrocarbons, whereas strains able to utilize aromatic hydrocarbons do not grow with n-alkanes. To investigate this specificity in more detail, three anaerobic n-alkane degraders (two denitrifying, one sulfate-reducing) and eight anaerobic alkylbenzene degraders (five denitrifying, three sulfate-reducing) were incubated with mixtures of n-alkanes and toluene. Whereas the toluene degradationers formed only the characteristic toluene-derived benzylsuccinate and benzoate, but no n-alkane-derived metabolites, the n-alkane degraders formed toluene-derived benzylsuccinate, 4-phenylbutanoate, phenylacetate and benzoate besides the regular n-alkane-derived (1-methylalkyl)succinates and methyl-branched alkanoates. The co-metabolic conversion of toluene by anaerobic n-alkane degraders to the level of benzoate obviously follows the anaerobic n-alkane degradation pathway with C-skeleton rearrangement and decarboxylation rather than the β-oxidation pathway of anaerobic toluene metabolism. Hence, petroleum-derived aromatic metabolites detectable in anoxic environments may not be exclusively formed by genuine alkylbenzene degraders. In addition, the hitherto largely unexplored fate of fumarate hydrogen during the activation reactions was examined with (2,3-2H2)fumarate as co-substrate. Deuterium was completely exchanged with hydrogen at the substituted carbon atom (C-2) of the succinate adducts of n-alkanes, whereas it is retained in toluene-derived benzylsuccinate, regardless of the type of enzyme catalysing the fumarate addition reaction.

Details

ISSN :
14622912
Volume :
13
Database :
OpenAIRE
Journal :
Environmental Microbiology
Accession number :
edsair.doi...........136920c275e0c4f2b58f7637e3576ab4
Full Text :
https://doi.org/10.1111/j.1462-2920.2011.02529.x