6th International Young Scientist Congress (IYSC-2020) will be Postponed to 8th and 9th May 2021 Due to COVID-19. 10th International Science Congress (ISC-2020).  International E-publication: Publish Projects, Dissertation, Theses, Books, Souvenir, Conference Proceeding with ISBN.  International E-Bulletin: Information/News regarding: Academics and Research

Solubilisation of Uganda low grade Rock Phosphate by Pseudomonas fluorescence

Author Affiliations

  • 1PG Dept of Environmental Sciences, Sambalpur University, Jyotivihar, Odisha, INDIA
  • 2 Environment Cell, R and D, Hindalco Industries Limited, Hirakud, Sambalpur, Odisha, INDIAI
  • 3 nstitute of Minerals $ Materials Technology(CSIR), Bhubaneswar, Odisha, INDIA

Res. J. Recent Sci., Volume 2, Issue (ISC-2012), Pages 250-254, February,2 (2013)


Most agricultural soils contain large reserves of phosphorus (P), a considerable part of which accumulates as a consequence of regular applications of P fertilizers. However, a greater part of soil phosphorus, approximately 95–99% is present in the form of insoluble phosphates and hence cannot be utilized by the plants. In the present study phosphate solubilising activity of Pseudomonas fluorescence against three types of rock phosphate (RP) were studied with respect to different parameters like temperature, incubation period, pulp density and effect of different carbon and nitrogen sources. Results indicated that the lower the concentration of the phosphate in the leaching broth the greater was the dissolution percentage of P2O5. A maximum of 44.70, 48.84 and 56.17(mg%) of P2O5 solubilisation were obtained after 15 days of incubation at 35ēC from West valley, North valley and South valley rock phosphate, respectively at 0.5 % pulp density. Acidic pH medium was favourable for phosphate solubilisation in all the experiments. Among the carbon sources glucose followed by maltose and sucrose supported the maximum RP solubilization in the presence of 0.5% pulp density as the optimum concentration. Nitrogen in the form of ammonium was very effective in solubilizing rock phosphates by P. fluorescence.


  1. Chunqiao Xiao, Ruan Chi, Xiao Pan, Feng Liu and Jiawi He, Rock phosphate solubilisation by four yeast strains, Annals of Microbiology, DOI 10.1007/s 13213-012-0458/z (2012)
  2. Prasanna Aadarsh, Deepa V., Murthy Balakrishnan P, Deccaraman M., Sridhar R., Dandapani P, Insoluble phosphate solubilisation by Bacterial strains isolated from Rice rhizosphere soil from Southern India, Int. J. of Soil Sc., 6(2) 134-141 (2011)
  3. Raval A.A and Desai P.B., Rhizobacteria from Rhizosphere of Sunflower (Helianthus annus. L.) and their effect on plant growth, Research J. of Recent Sciences, 1(6) 58-61 (2012)
  4. Fernandez L.A., Zalba P., Gomez M.A., Sagordoy M.A., Phosphate solubilisation activity of bacterial strains in soil and their effect on soybean growth under green house conditions, Biol. Fertil. Soils43, 805-809 (2007)
  5. Turan M.N., Ataoglu and Sahin F., Evaluation of the capacity of phosphate solubilizing bacteria and fungi on different forms of phosphorus in liquid culture, J. Sustainable Agri., 28, 99-108 (2006)
  6. Arcand M.M. and Schneider K.D., Plant and microbialbased mechanisms to improve the agronomic effectiveness of phosphate rock: A review, Ann. Acad. Bras. Cienc., 78, 791–807 (2006)
  7. Gyaneshwar P., Kumar G.N., Parekh L.J. and Poole P.S., Role of soil microorganisms in improving P nutrition of plants, Plant Soil, 245, 83–93 (2002)
  8. Sharma Sonam, Kumar Bijay and Tripathy Ram Babu, Isolation of phosphate solubilising microorganism from soil, J. Microbiol. Biotech Res, 1(2), 90-95 (2011)
  9. Jackson M.L., Soil chemical analysis,Prentice-Hall, New Delhi, India (1967)
  10. Zhu Fengling, Qu Lingyun, Hong Xuguang and Sun Xiuqin, Evidence based Complementary and alternative medicine 11, 1-6 (2011)
  11. Reddy M.S., Kumar S., Babita K. and Reddy M.S., Biosolubilization of poorly soluble rock phosphate by Aspergillus tubingensis and Aspergillus niger, Bioresource Technology,84, 187-189 (2002)
  12. Gaur A.C. and Sacher S., Effect of rock phosphate and glucose concentration on phosphate solubilisation by Aspergillus awamori, Curr Sci., 49, 553-554 (1984)
  13. Dave A. and Patel H.H., Phosphorous uptake by P. fluorescence and effect of external phosphate on microbial solubilisation, Asian J. of Microbiol. Biotech. Env. Sc., 10(1), 1-4 (2008)
  14. Ivanova R., Bozinova D. and Nedialkova K., Rock phosphate solubilisation by soil bacteria, Jr. of the Univ. of chemical Technol. and Metallurgy, 41(3), 297-302 (2006)
  15. Kpomblekou A.K. and Tabatabai M., AEffect of organic acids on release of phosphorous from phosphate rocks, Soil Sci., 158, 442-444 (1994)
  16. Narsian V., Thakker J. and Putei H.H., Mineral phosphate solubilisation by Aspergillus aculeatus, Ind. J. Exp. Biol.,33, 91-93 (1995)
  17. Gaind S. and Gaur A.C., Influence of temperature on the efficiency of phosphate solubilising microorganisms, Ind. J. Micro boil, 30, 305-310 (1990)
  18. Sayer J.A. and Gadd G.M., Solubilization and precipitation of metals by fungi, Minerol. Soc. Bull., 3-5 (1998)
  19. Gharieb M.M., Sayer J.A. and Gadd G.M., Solubilization of natural gypsum (CaSO.2HO) and the formation of calcium oxalate by Aspergillus niger and serpula himantioidies, Mycol. Res,102, 825-830 (1997)
  20. Kim K.Y., Jordan D. and Kirshanan H.B., Rahnella aquatilis, a bacterium isolated from soyabean rhizosphere, can solubilize hydroxyapatite, FEMS Micobiol. Lett,153, 273-277 (1997)
  21. Seshadre S., Muthukumarasamy R, Lakshminarasimhan C and Ignaacimuthu S., Solubilization of inorganic phosphates by Azospirillum halopraeferans, Curr. Sci., 79(5), 565-567 (2002)
  22. Kang S.C., Ha G.C., Lee T.G. and Maheshwari D.K., Solubilization of insoluble inorganic phosphates by a soil inhabiting fungus sp. Ps 102, Curr. Sci., 79(5), 439-442(2002)
  23. Rosado A.S., De Azevedo F.S., Da Croz, D.W. Van Elas and J.D. Seldin L., Phenotypic and genetic diversity of Paeni bacillusazatofeixans strains isolated from the rhizosphere soil of different grasses, J. Appl. Microbiol., 84, 216-226 (1998)
  24. Gilberto O. Mends, Carla S. Dias, Ivo R. Silva, Jose Ivo Ribeiro Junior, Olnto l. Pereira and Mauricio D. Costa, Fungal Rock Phosphate solubilisation using sugar cane baggase, World J. of Microbiology and Biotechnology, 12(1) 43-50 (2013)
  25. Varsha N.H.H., Aspergillus aculeatus as a rock phosphate solubilizer, Soil Biol. Biochem,32, 559-565 (2002)