Full Length Research Paper

Molecular characterization of Azotobacter spp. nifH gene Isolated from marine source

Rajeswari K.¹* and Mangai Kasthuri G.²

¹G. R. Damodaran College of Arts and Science, Coimbatore, India.

²Madurai Meenakshi College, Madurai, India.

*Corresponding author. E-mail: rajimicro_grd@yahoo.co.in.

Accepted 1 October, 2009

   Abstract

The nifH gene sequence of the nitrogen-fixing bacterium Azotobacter spp. was determined with the use of polymerase chain reaction (PCR). The Azotobacter species was isolated from marine source in two different seasons. They were cultivated under laboratory conditions using Nitrogen free Azotobacter specific medium. We observed that they were present in both seasons. The phylogenetic tree revealed that our isolated Azotobacter spp. was distantly related to uncultivated and uncultured organisms. They did not form any branch with other Azotobacter spp. in the data base.

Key words: Azotobacter, nifH, PCR, nitrogenase, biological nitrogen fixation.