Co-Immobilization of Bacillus Megaterium and Rhizobium Leguminosarum for Efficient Phosphorus and Nitrogen Fixation on Cicbr Aeritenum Moorthi P. Sathiya1, Deecaraman M1, Kalaichelvan P.T.2 1Department of Industrial Biotechnology, Dr. MGR Educational and Research Institute, Dr. MGR University, Chennai, India 2Centre for Advanced Studies in Botany, University of Madras, Guindy campus, Chennai, India Abstract Phosphate solubilizing efficacy of Bacillus megaterium and nitrogen fixation by Rhizobium leguminasarum were determined as free cells and sodium alginate co-immobilized beads. Phosphatase activity was determined at different parameters like pH, temperature, salinity, glucose concentration, and organic manure. The optimum solubilization occurs at the pH ranging from 7 to 7.5 on Pikovskaya agar plates and the maximum solubilization efficiency was obtained at 273.33 ± 15.56 (S.E). The temperature of 28°C was found to be optimum and the maximum solubilization efficiency was observed as 251 ± 5.56. While above 37°C, solubilization efficiency was decreased. The maximum solubilization efficiency (390 ± 11,87) was recorded at 0.4% sodium chloride. The total activity of phosphatase was determined in different concentration of glucose and organic manure on Pikovskaya broth. The phosphatase activity was increased as 603.33 ± 31.11 unit/ml at 5% glucose concentration. The organic manure also improved the phosphatase activity (903.33 ± 37.78 unit/ml). In pot experiment, Cicer aeritenurn (Chickpea) treated with B. megaterium alone and B. megaterium with R. leguminosarum were carried out in the form of free cell, immobilized beads, and immobilized seeds prepared with sodium alginate. When compared to free cell treatment, maximum growth was observed in the immobilized seeds and beads. The immobilized seed treatment showed faster germination in the initial days when compared to the free cell treatment. The growth of C. aeritenurn was observed on 16th day as 26 cm. In the initial days, free cell treatment showed microbial population of 160 ± 2.67 CFU/g of soil whereas, in the final days microbial population increased in the immobilized bead treatment showed 145.67 ± 2.22 CFU/g of soil. Nitrogenase activity was determined by acetylene reduction method. The maximum activity was found to be 16.76 ± 1.26 nmol C2H2/mg protein/hour in immobilized conditions. Top Keywords immobilization, phosphate solubilization, nitrogen fixation, Cicer arietinm, Bacillus megaterium. Top |