Talabani et al.: Classical and molecular approaches for identification of Rhizobium leguminosarium, Azotobacter chroococcum and Bacillus megaterium -12491 -APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH 17(5):12491-12506. Abstract. The present study aimed to identify of Rhizobium leguminosarium from Broad bean nodules, Azotobacter chrococcum and Bacillus megaterium from the soil in Sulaimani city/Iraq. Cultural characteristics showed that the colonies of bacteria were circular, smooth convex, and

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... ite color in Rhizobium leguminosarium and Bacillus megaterium, while creamy colored for Azotobacter chrococcum. The isolated bacteria were motile, rod, and gram-negative in Rhizobium leguminosarium and Azotobacter chrococcum, and gram-positive in Bacillus megaterium. Biochemical tests found that Rhizobium leguminosarium was positive for Catalase and negative for Indole Production, Methyl Red, Vogas Proskauer, Citrate Utilization and Gelatinase, Azotobacter chrococcum was positive for Catalase and Citrate Utilization, while Bacillus megaterium was positive for Catalase, Citrate Utilization and Gelatinase. Rhizobium leguminosarium utilized Starch Glucose, Mannitol, Galactose, Raffinose, Trehalose, Mannose and Xylose, but Azotobacter chrococcum did not utilize Galactose and xylose, while Bacillus megaterium did not utilize Trehalose . The molecular method based on the detection of plasmid DNA, nodD2 and nodD3 in Rhizobium leguminosarium, chromosomal DNA, nifH2 and nifH3 in Azotobacter chrococcum, genomic DNA and two random primers in Bacillus megaterium on gel electrophoresis have been successfully applied. We conclude that cultural, morphological and biochemical tests used for identification of these isolates was equivalent to the molecular-based method. Talabani et al.: Classical and molecular approaches for identification of Rhizobium leguminosarium, Azotobacter chroococcum and Bacillus megaterium -12492 -APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH 17(5):12491-12506.