Affiliation:
1. Institutet för Vatten-och Luftvårdsforskning, S-100 31 Stockholm, Sweden
Abstract
Using selective media containing galactitol, over 130
Enterobacteriaceae
have been isolated from paper mill process waters collected from different localities. These bacteria were extensively characterized and tested for acetylene-reducing (nitrogen-fixing) activity under anaerobic conditions. High activity was found in representatives of
Klebsiella pneumoniae, Enterobacter aerogenes, Enterobacter cloacae, Erwinia herbicola, Citrobacter freundii, Citrobacter intermedius
, and
Escherichia coli
. Under argon, nitrogenase synthesis was generally not repressed by 5 mM
l
-glutamate,
l
-aspartate,
l
-leucine or Casamino Acids (0.5 g/liter). In many strains, both the specific activities (nanomoles of C
2
H
4
per minute per milligram of protein) and the activities (nanomoles of C
2
H
4
per minute) had considerably declined after 24 h. In three selected strains, activity in intact cells grown under nitrogen was unaffected by the presence during assay of 10 mM
l
-amino acids or ammonium acetate. All of the strains examined were tolerant towards inactivation of nitrogen-fixing activity by 1.8% (vol/vol) oxygen during assay, and inactivation by up to 10% oxygen was partly reversible. Representatives of the six taxa synthesized nitrogenase in stirred aerobic cultures, though the protein concentrations attained were lower than under anaerobic conditions. It seems reasonable to suggest that under natural conditions, nitrogen fixation is able to contribute significantly to the nitrogen economy of the cells.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
65 articles.
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