Journal of Biotechnology & Biomaterials
Open Access

Abstract

Rice is one of the important cereal crops in the world, grown in the diverse environmental conditions. Plant root secrets different type of low and high molecular weight secondary compounds that affects rhizosphere microbial population. Rice crop absorb nitrogen in ammonical form for their growth and development in huge amount. In this study, biochemical characterization of nitrogen fixing bacteria were carried out on ten soil samples from different rice varieties rhizosphere of Directorate of Seed Research (DSR) field in 2011-2012. Diazotrophs were isolated on nitrogen free semisolid media i.e Jenson medium, Yeast Extract Mannitol Agar medium, and Ashby Sucrose Agar medium with different different carbon sources and pH values by using serial dilution method. A total number of 30 rhizobacteria of different morphotypes were selected and biochemically characterized (qualitative and quantitative) IAA production, HCN production and Siderophore production using ferric chloride perchloric reagent, glycine and CAS dye amended medium, respectively. Out of 37, 4 rhizobacterial isolates produced IAA (JA3,JB4, JD3 and JE2), 10 rhizobacterial isolates produced HCN (JA3, JE2, JF1, JH1, JH3, Y1, Y2, Y4, Y7 and Y9) and also 20 rhizobacterial isolates produced siderophore (JA1, JA2, JA3, JC2, JD1, JD3,JE1, JE2, JF1, JH1, JH2, JH3, Y1, Y4, Y6, Y7, Y9, Y10, A1, and A4) were screened in qualitative estimation. In another experiment, plant growth promoting traits as IAA, HCN and Siderophore production were estimated quantitatively. The rhizobacterial isolates that given positive results in qualitative screening were very much potential to secondary metabolites in comparisons to the others by calculating Optical Density (OD) using spectophotometer at 530nm. The results are of potential rhizobacterial isolates were showed all these three characteristics as IAA, HCN and Siderophore production i.e JA3- 1.143, 1.383, 1.592 and JE2- 1.681, 1.900 and 1.492, respectively. Therefore, isolation, identification and characterization of potential rhizobacteria are very much future concern.

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