Behaviour of Nif− mutants of Rhodobacter capsulatus in photosynthetic, ammonia-limited chemostat cultures |
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Authors: | John C Willison Bruno Lac |
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Institution: | Laboratoire de Biochemie Microbienne (CNRS UA 1130), Département de Recherche Fondamentale, Centre d'Etudes Nucléaires de Grenoble, Grenoble, France |
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Abstract: | Abstract Nif? mutants of Rhodobacter capsulatus carrying mutations either in the nifR4 regulatory gene or in the nifH structural gene both outgrew the wild-type strain B10 in mixed chemostat cultures under conditions favouring nitrogenase-mediated H2 production by the wild-type (ammonia as limiting nutrient, inert argon atmosphere, light as energy source), whereas under aerobic conditions in the dark, or in batch culture, the growth of Nif? mutants was not favoured. Nitrogenase-mediated H2 production therefore appears to be detrimental to the growth of R. capsulatus in nitrogen-limited continuous culture, as may also be the case for other nitrogen fixers. |
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Keywords: | Nif? mutants Rhodobacter capsulatus Continuous culture H2 production |
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