Open AccessNitrogen‐limited behaviour of micro‐organisms growing in the presence of large concentrations of ammonium ions
Author(s) -
Buurman Ed T.,
Mattos M.Joost Teixeira,
Neijssel Oense M.
Publication year - 1989
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1989.tb03049.x
Subject(s) - chemostat , ammonium , ammonia , extracellular , biochemistry , cytoplasm , chemistry , nitrogen , ammonium sulfate , biology , bacteria , biophysics , chromatography , organic chemistry , genetics
Cells of Klebsiella pneumoniae NCTC 418 grown at low culture pH values (4.5–5) in a glucose‐limited chemostat culture contained elevated levels of glutamate synthase (EC 2.6.1.53). This can be taken as an indication that these cells show the physiology of nitrogen‐limited cells, in spite of the fact that high concentrations (about 80 mM) of ammonium ions were present in the culture extracellular fluids. This phenomenon can be explained by the rapid diffusion of ammonia (NH 3 ) through the cell membrane, leading to very low cytoplasmic ammonium (NH 4 + ) and NH 3 levels in cells that possess an almost neutral cytoplasmic pH value, but are growing at low culture pH values.