ISOLATION AND CHARACTERIZATION OF NITROGEN FIXING AND INDOLE ACETIC ACID

ABSTRACT

The need for an alternative to inorganic fertilizers is on the increase owing to the drawbacks associated with organic fertilizers. This study was therefore carried out to evaluate the bacteriological profile of anthill soil in the University of Benin and its surroundings. In other to ix find isolates that have the ability to fix nitrogen and indole acetic acid in the soil as well as their ability to promote plant growth. Standard bacteriological methods were used to analyze the isolates from different locations. Total heterotrophic count was obtained using pour plate method. The cultural, morphological and biochemical characteristics were evaluated using standard differential media along with appropriate reagents. Plant growth promoting capacity of the isolates were evaluated using standard protocol for nitrogen fixation and indole acetic acid production. The results obtained from the study revealed that the heterotrophic bacterial count (Log10 cfu/g) of the anthill soils analyzed ranged from 7.42 ± 0.02 cfu/g to 6.17 ± 0.08 cfu/g The cultural, morphological and biochemical isolates revealed the presence of Pseudomonas aeruginosa, Shigella boydii, Klebsiella pneumoniae, Bacillus sp., Staphyloccus sp., Micrococcus luteus and Corynebacterium sp.The results showed that all bacterial isolates were found to possess plant growth promoting properties with 100% able to fix nitrogen and 43% able to produce indole acetic acid.