Novel approach for the determination of nitrogen fixation in cyanobacteria

Sumaira Mazhar, Jerry D. Cohen, Shahida Hasnain

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Summary: Non-heterocystous nitrogen fixing strains of cyanobacteria were screened by their ability to grow in nitrogen deficient media. The selected nitrogen fixing cyanobacterial cells were then cultured in BG11 media supplemented with [ 15 N]-labeled sodium nitrate. Under these growth conditions any organic [ 14 N] found in the cyanobacterial cells would simply come from nitrogen fixation because [ 15 N] was the only available source of nitrogen in the medium. Amino acids extracted after different time periods (after 15, 30, 40, 50 and 60 days of inoculation) were used for the determination of the 14 N/ 15 N ratio using GC-MS. Results from the present study support the conclusion that at stationary phase of growth cyanobacterial nitrogen fixation was no longer supplying a significant amount of nitrogen. This approach not only provided a detailed method for the evaluation of the nitrogen fixing potential of the cyanobacteria in culture, but also suggests novel approaches for the assessment of the ability of the strains to provide nitrogen enrichment to plants under co-cultivation conditions.

Original languageEnglish (US)
Pages (from-to)105-112
Number of pages8
JournalJournal of the Chemical Society of Pakistan
Issue number1
StatePublished - 2019

Bibliographical note

Funding Information:
Higher Education Commission (HEC) of Pakistan, Minnesota Agricultural Experiment Station (USA) and US-NSF-DBI-0606666 are acknowledged for providing the financial support to Ms. Sumaira Mazhar to visit the Department of Horticultural Science and the Microbial and Plant Genomics Institute, University of Minnesota, USA to do the GC-MS quantification of IAA. We thank Wen Ping Chen for help with GC-MS analysis.

Publisher Copyright:
© 2019 Chemical Society of Pakistan. All rights reserved.


  • Amino acids
  • Cyanobacteria
  • GC-MS
  • Nitrogen Fixation


Dive into the research topics of 'Novel approach for the determination of nitrogen fixation in cyanobacteria'. Together they form a unique fingerprint.

Cite this