Heterotrophic nitrification by Pseudomonas aeruginosa

Effects of Organic Acids on Heterotrophic Nitrification byAlcaligenes faecalisOKK17

“…Since Quastel and Scholefield 27 ,28) reported that oximes of pyruvic, oxaloacetic, phenylpyruvic, and 2-oxoglutaric acids are readily oxidized by soil microorganisms, pyruvic oxime 2 ,10,12-15) and acetaldoximes 16 ) have been used as substrates for heterotrophic nitrification by isolated bacteria. However, those studies presumed that oximes are supplied exogenously in natural environments, and evidence showing that heterotrophic nitrifiers can make oximes from organic acids has not been found.…”

Heterotrophic nitrification by a thermophilicBacillusspecies as influenced by different culture conditions

“…First, numerous organic and inorganic substances can be used as N-sources for heterotrophic nitrification (Focht and Verstraete 1977), and an organic carbon source is necessary not only for growth of the organisms, but also for nitrification of at least inorganic N-sources (Hylin and Matsumoto 1960;Verstraete and Alexander 1972b). Concerning the products of heterotrophic nitrification, hydroxylamine is often the intermediate product, and hydroxamates can be the main product (Verstraete 1974); but the final product of heterotrophic nitrification generally is nitrite (Obaton et al 1968;Verstraete andAlexander 1972a, 1972b;Castignetti and Hollocher 1984), although sometimes some nitrate formation was observed in bacterial cultures (Gunner 1963;Verstraete and Alexander 1972a;Castignetti and Gunner 1981;Papen et al 1989), and most fungi mainly excrete nitrate (Eylar and Schmidt 1959;Marshall and Alexander 1962). In addition, contrary to autotrophic nitrifiers, some heterotrophic microorganisms can carry out dual activity.…”

“…In contrast to the autotrophic nitrifiers, it has commonly been accepted that the heterotrophic nitrifiers are far less active and effective in their nitrification ability than autotrophic ones (Gode and Overbeck 1972;Focht and Verstraete 1977), and they mostly accumulate nitrite or nitrate when active growth of the cells has ceased (Alexander et al 1960;Doxtader and Alexander 1966;Obaton et al 1968;Verstraete and Alexander 1972a). These two latter points had led to the assumption that nitrite production by heterotrophs is a passive process linked to lysis of the cells (Alexander et al 1960;Marshall and Alexander 1962) and does not contribute to the energy budget of the cells (Aleem 1970).…”

Pyruvic oxime dioxygenase from heterotrophic nitrifier Alcaligenes faecalis is a nonheme Fe(II)-dependent enzyme homologous to class II aldolase

“…In the mid-20 th century, the relevance of oxime and nitro compounds to nitrification in several heterotrophic microorganisms was reported15161718. Alcaligenes faecalis is a betaproteobacterium that has been commonly used for investigation of heterotrophic nitrification, and pyruvic oxime (2-(hydroxyimino)propanoic acid), and not its hydrolysis product, NH 2 OH, was found to be involved in the ammonia oxidation pathway of A. faecalis 6.…”