ABSTRACT
Denitrifying bacteria, for example Pseudomonas denitrificans or Paracoccus denitrificans, transform nitrate to nitrogen gas and are used for the removal of nitrate from water and wastewater under anoxic conditions. Iron-reducing bacteria can reduce different Fe(III) compounds and are important in the anaerobic biodegradation of organics in the aquifers. Sulfate-reducing bacteria are obligate anaerobes that use organic compounds as energy sources. Sulfate or elemental sulfur serves as the terminal electron acceptor in anaerobic respiration and hydrogen sulfide is the toxic product of this process. Methanogens make up a group of Archaea. They are strict anaerobes that convert CO2, methyl compounds, or acetate to methane gas by anaerobic respiration. This group is extremely important in the anaerobic digestion of organic matter. A tutorial with solutions and a quiz bank are added to this chapter.
