Cells and microorganisms having nitrogen fixation genes - and a NIFLA operon, have under-gone a mutation to confer pheno-type NIF-C, and have nitrogenase activity in the presence of ammonium ions

摘要

Cell or microorganism having a combination of nitrogen fixation (nif) genes and a nifLA operon which has undergone a mutation which confers NifC phenotype to the cell or micro- organism. Pref. the mutation is localised in nifL locus. Used for the nifLA operon showing the mutation is carried by a plasmid (esp. at least one part of the DNA of pCE1 plasmid) or a chromosome. The microorganism is pref. a bacteria having recA character esp. a strain of Klebsiella pneumoniae. Fixation of atmos. nitrogen by cells or microorganisms esp. bacteria. Normally nitrogen fixation organisms can only operate under conditions where they are deprived of combined nitrogen (i.e. chemically bound nitrogen, esp. ammonium and nitrate salts), the mutation allows the genes to confer nitrogen fixing activity in the presence of ammonium ions, independently of the control exerted by glutamine synthetase.