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The microbial community present in the produced waters from the Enermark field during nitrate injection is determined by denaturing gradient gel electrophoresis (DGGE) and the fate of the injected nitrate is determined by monitoring ammonium concentration in produced and injection waters. The results have shown that nitrate injected into an oil field to oxidize sulfide is reduced by denitrifying bacteria and that perhaps counterintuitively, nitrate injection has led to decreasing ammonium concentrations in produced waters.

Anaerobic ammonium-oxidizing (anammox) bacteria have been recognized as an important sink for fixed nitrogen and are detected in many natural environments. However, their presence in terrestrial ecosystems has long been overlooked, and their contribution to the nitrogen cycling in natural and agricultural soils is currently unknown. Here we describe the enrichment and characterization of anammox bacteria from a nitrogen-loaded peat soil. Ater 8 months of incubation with the natural surface water of the sampling site and increasing ammonium and nitrite concentrations, anammox cells constituted 40 to 50% of the enrichment culture. The two dominant anammox phylotypes were affiliated with "Candidatus Jettenia asiatica" and "Candidatus Brocadia fulgida." The enrichment culture converted NH4+ and NO2- to N2 with the previously reported stoichiometry (1:1.27) and had a maximum specific anaerobic ammonium oxidation rate of 0.94 mmol NH4+ g (dry weight)-1 ∙ h-1 at pH 7.1 and 32°C. The diagnostic anammox-specific lipids were detected at a concentration of 650 ng ∙ g (dry weight)-1, and pentyl-[3]-ladderane was the most abundant ladderane lipid. [ABSTRACT FROM AUTHOR]

During the last century, the research on aerobic ammonium-oxidizing bacteria (AOB) lead to many exciting physiological and biochemical discoveries. Nevertheless the molecular biology of AOB is not well understood. The availability of the genome sequences of several Nitrosomonas species opened up new possiblities to use state of the art transcriptomic and proteomic tools to study AOB. With the currect technology, thousands of proteins can be analyzed in several hours of measurement and translated proteins can be detected at femtomole and attomole concentrations. Moreover, it is possible to use mass spectrometry-based proteomics approach to analyze the expression, subcellular localization, posttranslational modifications, and interactions of translated proteins. In this chapter, we describe our LC-MS/MS methodology and quality control strategy to study the protein complement of Nitrosomonas eutropha C91., (Copyright © 2011 Elsevier Inc. All rights reserved.)