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Autotrophic and heterotrophic mechanisms for ammonia oxidation
Author(s) -
Wood P.M.
Publication year - 1990
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/j.1475-2743.1990.tb00807.x
Subject(s) - nitrification , chemistry , heterotroph , autotroph , environmental chemistry , ammonia , radical , ammonia monooxygenase , nitrogen cycle , nitrogen , organic chemistry , bacteria , biology , genetics
. Autotrophic nitrifiers such as Nitrosomonas use ammonia mono‐oxygenase for the initial stage of ammonia oxidation. Nitrification inhibitors have this enzyme as their site of action. Their mechanisms include alternative substrates, suicide substrates and cuprous copper chelators. In heterotrophs, organic nitrogen is normally in the fully reduced state, but a few cell metabolites contain N‐O bonds. The synthesis and breakdown of such compounds provides a mechanism for heterotrophic nitrification. A non‐enzymic mechanism for nitrogen‐oxidation involves hydroxyl radicals produced by the Fenton reaction. Heterotrophic nitrification is particularly important in woodland soils, where wood‐rotting fungi use free radicals to break down lignin. Tests for a radical mechanism are described.