gen. nov., sp. nov., a novel sulphate-reducing bacterium in the capable of autotrophic growth with hydrogen or elemental iron.

A mesophilic sulphate-reducing micro-organism, able to grow chemolithoautotrophically with H/CO (20 : 80) and with elemental iron as a sole electron donor, was isolated from a consortium capable of degrading long-chain paraffins and designated strain DRH4. Cells were oval shaped often with bright refractile cores and occurred singly or in pairs. The cells formed pili.

Composition and Corrosivity of Extracellular Polymeric Substances from the Hydrocarbon-Degrading Sulfate-Reducing Bacterium ALDC.

Sulfate-reducing bacteria (SRB) often exist as cell aggregates and in biofilms surrounded by a matrix of extracellular polymeric substances (EPSs). The chemical composition of EPSs may facilitate hydrophobic substrate biodegradation and promote microbial influenced corrosion (MIC). Although EPSs from non-hydrocarbon-degrading SRB have been studied; the chemical composition of EPSs from hydrocarbon-degrading SRBs has not been reported.

The Complete Genome Sequence of -Alkane-Degrading Desulfoglaeba alkanexedens ALDC Reveals Multiple Alkylsuccinate Synthase Gene Clusters.

Anaerobic alkane metabolism is critical in multiple environmental and industrial sectors, including environmental remediation, energy production, refined fuel stability, and biocorrosion. Here, we report the complete gap-closed genome sequence for a model -alkane-degrading anaerobe, ALDC.

Design features of offshore oil production platforms influence their susceptibility to biocorrosion.

Offshore oil-producing platforms are designed for efficient and cost-effective separation of oil from water. However, design features and operating practices may create conditions that promote the proliferation and spread of biocorrosive microorganisms. The microbial communities and their potential for metal corrosion were characterized for three oil production platforms that varied in their oil-water separation processes, fluid recycling practices, and history of microbially influenced corrosion (MIC).

Metabolic Capability of a Predominant Halanaerobium sp. in Hydraulically Fractured Gas Wells and Its Implication in Pipeline Corrosion.

Microbial activity associated with produced water from hydraulic fracturing operations can lead to gas souring and corrosion of carbon-steel equipment. We examined the microbial ecology of produced water and the prospective role of the prevalent microorganisms in corrosion in a gas production field in the Barnett Shale. The microbial community was mainly composed of halophilic, sulfidogenic bacteria within the order Halanaerobiales, which reflected the geochemical conditions of highly saline water containing sulfur species (S2O3 (2-), SO4 (2-), and HS(-)).

Methanogenic paraffin degradation proceeds via alkane addition to fumarate by 'Smithella' spp. mediated by a syntrophic coupling with hydrogenotrophic methanogens.

Anaerobic microbial biodegradation of recalcitrant, water-insoluble substrates, such as paraffins, presents unique metabolic challenges. To elucidate this process, a methanogenic consortium capable of mineralizing long-chain n-paraffins (C28 -C50 ) was enriched from San Diego Bay sediment. Analysis of 16S rRNA genes indicated the dominance of Syntrophobacterales (43%) and Methanomicrobiales (26%).

gen. nov., sp. nov., isolated from a methanogenic paraffin-degrading enrichment culture and emended description of the family .

A mesophilic deltaproteobacterium, designated strain SPR, was isolated from a methanogenic consortium capable of degrading long-chain paraffins. Cells were motile, vibrio-shaped, and occurred singly, in pairs or in clusters. Strain SPR did not metabolize hydrocarbons but grew fermentatively on pyruvate and oxaloacetate and autotrophically with H and CO.

Issues for storing plant-based alternative fuels in marine environments.

Two coastal seawaters (Key West, FL, USA and the Persian Gulf, Bahrain, representing oligotrophic and eutrophic environments, respectively) were used to evaluate potential biodegradation and corrosion problems during exposure to alternative and conventional fuels. Uncoated carbon steel was exposed at the fuel/seawater interface and polarization resistance was monitored. Under typical marine storage conditions, dioxygen in natural seawater exposed to fuel and carbon steel was reduced to <0.

Sulphide production and corrosion in seawaters during exposure to FAME diesel.

Experiments were designed to evaluate the corrosion-related consequences of storing/transporting fatty acid methyl ester (FAME) alternative diesel fuel in contact with natural seawater. Coastal Key West, FL (KW), and Persian Gulf (PG) seawaters, representing an oligotrophic and a more organic- and inorganic mineral-rich environment, respectively, were used in 60 day incubations with unprotected carbon steel. The original microflora of the two seawaters were similar with respect to major taxonomic groups but with markedly different species.

Involvement of thermophilic archaea in the biocorrosion of oil pipelines.

Two thermophilic archaea, strain PK and strain MG, were isolated from a culture enriched at 80°C from the inner surface material of a hot oil pipeline. Strain PK could ferment complex organic nitrogen sources (e.g.

Field and laboratory studies on the bioconversion of coal to methane in the San Juan Basin.

The bioconversion of coal to methane in the San Juan Basin, New Mexico, was investigated. Production waters were analyzed via enrichment studies, metabolite-profiling, and culture-independent methods. Analysis of 16S rRNA gene sequences indicated the presence of methanogens potentially capable of acetoclastic, hydrogenotrophic, and methylotrophic metabolisms, predominantly belonging to the Methanosarcinales and Methanomicrobiales.

Methanogenesis, sulfate reduction and crude oil biodegradation in hot Alaskan oilfields.

Petrochemical and geological evidence suggest that petroleum in most reservoirs is anaerobically biodegraded to some extent. However, the conditions for this metabolism and the cultivation of the requisite microorganisms are rarely established. Here, we report on microbial hydrocarbon metabolism in two distinct oilfields on the North Slope of Alaska (designated Fields A and B).

Diversity of benzyl- and alkylsuccinate synthase genes in hydrocarbon-impacted environments and enrichment cultures.

Hydrocarbon-degrading microorganisms play an important role in the natural attenuation of spilled petroleum in a variety of anoxic environments. The role of benzylsuccinate synthase (BSS) in aromatic hydrocarbon degradation and its use as a biomarker for field investigations are well documented. The recent discovery of alkylsuccinate synthase (ASS) allows the opportunity to test whether its encoding gene, assA, can serve as a comparable biomarker of anaerobic alkane degradation.

Anaerobic phenanthrene mineralization by a carboxylating sulfate-reducing bacterial enrichment.

Information on the susceptibility of higher molecular weight polynuclear aromatic hydrocarbons to anaerobic biodegradation is relatively rare. We obtained a sulfate-reducing bacterial enrichment capable of phenanthrene metabolism from a hydrocarbon-contaminated marine sediment. Phenanthrene degradation was in stoichiometric agreement with the theoretically expected amount of sulfate reduction and inhibited by molybdate.

Desulfoglaeba alkanexedens gen. nov., sp. nov., an n-alkane-degrading, sulfate-reducing bacterium.

Two novel sulfate-reducing bacteria, strains ALDC(T) and Lake, which were able to oxidize n-alkanes, were isolated from a naval oily wastewater-storage facility (VA, USA) and from oilfield production water (OK, USA), respectively. The type strain (ALDC(T)) had a narrow substrate specificity and could grow only with n-alkanes (from C(6) to C(12)), pyruvate, butyrate, hexanoic acid and 4-methyloctanoic acid. Cells of strain ALDC(T) stained Gram-negative and were slightly curved, short rods with oval ends (2.

Stable isotopic studies of n-alkane metabolism by a sulfate-reducing bacterial enrichment culture.

Gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy were used to study the metabolism of deuterated n-alkanes (C6 to C12) and 1-13C-labeled n-hexane by a highly enriched sulfate-reducing bacterial culture. All substrates were activated via fumarate addition to form the corresponding alkylsuccinic acid derivatives as transient metabolites. Formation of d14-hexylsuccinic acid in cell extracts from exogenously added, fully deuterated n-hexane confirmed that this reaction was the initial step in anaerobic alkane metabolism.

Enrichment and isolation of anaerobic hydrocarbon-degrading bacteria.

Recent progress in microbiology resulted in the enrichment and isolation of anaerobic bacteria capable of the biodegradation of various hydrocarbons under a variety of electron-accepting conditions. Problems challenging the enrichment and isolation of anaerobic hydrocarbonclastic organisms required new approaches and modifications of conventional microbiological techniques. This chapter summarizes the collective experience accumulated in this area starting from anaerobic sampling precautions and includes all stages of cultivation from the construction of initial incubations to final isolation steps and the evaluation of culture purity.