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The potential for modern coalfield methanogenesis was assessed using formation water from the Illinois Basin, Powder River Basin and Cook Inlet gas field as inocula for nutrient-replete incubations amended with C1-C5 fatty acids as presumed intermediates formed during anaerobic coal biodegradation. Instead of the expected rapid mineralization of these substrates, methanogenesis was inordinately slow (∼1 μmol day-1), following long lag periods (>100 days), and methane yields typically did not reach stoichiometrically expected levels. However, a gene microarray confirmed the potential for a wide variety of microbiological functions, including methanogenesis, at all sites. The Cook Inlet incubations produced methane at a relatively rapid rate when amended with butyrate (r = 0.98; p = 0.001) or valerate (r = 0.84; p = 0.04), a result that significantly correlated with the number of positive mcr gene sequence probes from the functional gene microarray and was consistent with the in situ detection of C4-C5 alkanoic acids. This finding highlighted the role of syntrophy for the biodegradation of the softer lignite and subbituminous coal in this formation, but methanogenesis from the harder subbituminous and bituminous coals in the other fields was less apparent. We conclude that coal methanogenesis is probably not limited by the inherent lack of metabolic potential, the presence of alternate electron acceptors or the lack of available nutrients, but more likely restricted by the inherent recalcitrance of the coal itself.

The metabolites formed during growth on hexadecane were surveyed by the sulfate reducing isolates AK-01 and Hxd3 and by a mixed sulfate reducing consortium. The findings suggest that fumarate addition and carboxylation are important alkane degradation mechanisms that may be widespread among phylogenetically and/or physiologically distinct microorganisms.

Research describes the alicyclic hydrocarbon, ethylcyclopentane, biodegradation under anaerobic conditions by a sulfate-reducing bacterial enrichment isolated from a gas condensate-contaminated aquifer. Results indicate that alicyclic hydrocarbons are anaerobically activated to form alkylsuccinate derivatives under sulfate-reducing conditions.

Researchers at the University of Oklahoma, Norman, Oklahoma, determined that the identification of signature microbial metabolites can be used to determine the anaerobic biodegradation of hydrocarbons. Alkylated aromatic contaminants were converted to their corresponding benzylsuccinic acid derivatives, which were further biodegraded to toulates, phthalates, and benzoate.

Researchers report a novel bioconversion of alkanes by sulfate-reducing bacteria under anaerobic conditions. The reaction proceeds without resonance stabilization by a conjugated pi system.

Researchers from the University of Oklahoma and the U.S. Geological Survey developed geochemical and microbiological methods in the evaluation of anaerobic sulfate reduction from contaminated aquifers from landfill leachate in Norman, Oklahoma.

Researchers from the University of Oklahoma collected samples of water from contaminated aquifers in Oklahoma and revealed the presence of sulfate-reducing bacteria caused by the accumulation of phenol and benzoate resulting in anaerobic benzene.

The extreme oxygen sensitivity of methanogenic bacteria and inherent limitations of culturing techniques make it difficult to accurately find a biomass value. The thiol biomarker coenzyme M (CoM), known to be in all methanogenic bacteria, is used. A high-performance liquid chromatography (HPLC)-based method for detecting thiols in pore water was modified to quantify CoM in pure cultures, sewage water or sediment. CoM derivative identity was verified through use of liquid-chromatography-mass spectroscopy.

Researchers from Oklahoma tested the hypothesis that intrinsic bioremediation occurs in a shallow gas condensate hydocarbon-contaminated groundwater using multiple lines of geochemical and biological evidence.

The abundance of acetogenic bacteria was found in subsurface sandstone and shale deposits during the Cretaceous period. This prompted scientists to study the terminal steps of the microbial food chain in anaerobic subsurface communities. Originally, these subsurface communities were thought to consume H2 and acetate in the same manner as their surface-borne counterparts. Most types of acetogenic bacteria have complex growth requirements and these processes are enhanced by the addition of glucose.

Anaerobic degradation, through the use of chronically hydrocarbon-contaminated marine sediments, of crude oil components result to almost complete removal of n-alkane. Near complete removal of n-alkane takes place when the predominant electron-accepting process used is sulfate reduction. Alteration of oil does not occur under the type of anaerobic degradation approach utilized.