African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12504

Full Length Research Paper

Influence of osmotic and metal stresses on nitrogenase activity of cyanobacteria ısolated from paddy fields

Gulten OKMEN (Kurucuoglu)1*, Gonul DONMEZ2 and Sedat DONMEZ3
1Muğla University, Faculty of Science and Arts, Department of Biology, Mugla, Turkıye. 2Ankara University, Faculty of Science, Department of Biology, Ankara, Turkıye. 3Ankara University, Faculty of Engineering, Department of Food Engineering, Ankara, Turkıye.
Email: [email protected]

  •  Accepted: 27 March 2007
  •  Published: 31 August 2007

Abstract

Samples were collected from paddy fields in Corum-Turkıye. Nitrogen-free BG-11 medium was used for isolation of nitrogen fixing cyanobacteria. Acetylene reduction technique was used to determine the effects of different chemical agents on the nitrogenase activities of the cyanobacteria, which were identified at the genus level.Nostoc showed the highest nitrogenase activity (0.09 ethylene µl/mg.h) at 50 mM salt concentration. At 60 mM sucrose concentration, Nostoc showed the highest nitrogenase activity (0.08 ethylene µl/mg.h). The highest tolerances for the metals were present in Anabaena (0.006 ethylene µl/mg.h) for iron (20 ppm), Nodularia 0.1 ethylene µl/mg.h (for manganese 20 ppm)  and Nostoc 0.96 ethylene µl/mg.h (for zinc 5 ppm) .

 

Key words: Cyanobacteria, nitrogenase activity, isolation, environmental factors.

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This article is published under the terms of the Creative Commons Attribution License 4.0

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