Isolation, Characterization and Growth of Rhizobium Strains under Optimum Conditions for Effective Biofertilizer Production

Author (s) : T.Bhuvana

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Abstract :
A gram-negative, soil-dwelling bacterium called rhizobium forms a symbiotic relationship with the roots of leguminous plants. For biological nitrogen fixation, screening and choosing the best strain are crucial. The goal of the current study was to provide insight into the growth, various traits, and Phytohormone (Indole Acetic Acid) secretion of Rhizobial Strains (Rhizobium trifolii, Rhizobium phaseoli, Bradyrhizobium japonicum, and Rhizobium leguminosarum) .The study revealed that by a series of morphological and biochemical test conducted, all the four strains were gram negative, rod shaped and mucous producing. All the strains grew well at pH 6 and 7, temperature 34 o C and at salt concentration 4%. Bradyrhizobium japonicum was found to be negative to bromothymol blue test, while all other three strains were positive depicting the former to be slow growing and later to be fast growing. All the strains were resistant to Penicillin and sensitive to Tetracycline. Rhizobium phaseoli produced starch hydrolysis while Rhizobium trifolii was positive in Caesinase test. B. japonicum, R. trifolii and R. phaseoli showed sufficient growth in Urease test and Lysine decarboxylase test. All four strains hydrolyzed lipase and Catalase enzyme. Citrate was used by Rhizobium trifolii and Rhizobium phaseoli, and fast-growing strains were better able to use carbon sources than slow-growing ones. Studies on the synthesis of indole acetic acid in aerobic and anaerobic circumstances revealed that Rhizobium trifolii and Rhizobium phaseoli produced the most in the aerobic state, at 0.4 and 0.6 g ml-1, respectively. Rhizobium was also used as a biofertilizer to significantly increase plant output and growth.

Keywords : Isolation, Characterization, Biofertilizers

Conference Date : 13/11/2020

Pages : 280

Paper ID : 20280