Phosphate solubilizing bacteria cultured in Petri dish. The zone of n clearance can be clearly seen.
Phosphate solubilizing bacteria (PSB) are beneficial bacteria capable of solubilizing inorganic phosphorus from insoluble compounds.
rock phosphate, it can save about 50% of the crop requirement of phosphatic fertilizer.[citation needed] The use of PSB as inoculants increases P uptake by plants. Simple inoculation of seeds with PSB gives crop yield responses equivalent to 30 kg P2O5 /ha or 50 percent of the need for phosphatic fertilizers. Alternatively, PSB can be applied through fertigation or in hydroponic operations. Many different strains of these bacteria have been identified as PSB, including Pantoea agglomerans (P5), Microbacterium laevaniformans (P7) and Pseudomonas putida (P13) strains are highly efficient insoluble phosphate solubilizers. Recently, researchers at Colorado State University demonstrated that a consortium of four bacteria, synergistically solubilize phosphorus at a much faster rate than any single strain alone.[3] Mahamuni and Patil (2012) isolated four strains of phosphate solubilizing bacteria from sugarcane (VIMP01 and VIMP02) and sugar beet rhizosphere (VIMP03 and VIMP 04). Isolates were strains of Burkholderia named as VIMP01, VIMP02, VIMP03 and VIMP04. VIMP (Vasantdada Sugar Institute Isolate by Mahamuni and Patil) cultures were identified as Burkholderia cenocepacia strain VIMP01 (JQ867371), Burkholderia gladioli strain VIMP02 (JQ811557), Burkholderia gladioli strain VIMP03 (JQ867372) and Burkholderia species strain VIMP04 (JQ867373).[4]
Additionally, phosphate (P) compounds are capable of immobilizing heavy metals, especially Pb, in contaminated environments through phosphate-heavy metal precipitation. However, most P compounds are not readily soluble in soils so it is not readily used for metal immobilization. Phosphate solubilizing bacteria (PSB) have the potential to enhance phosphate-induced immobilization of metals to remediate contaminated soil. However, there is a limit on the amount of phosphate which can be added to the environment due to the issue of eutrophication.[5]
Phosphate is often adsorbed onto the surface of different type of minerals, for example iron containing minerals. Recent data suggest that bacteria growing under phosphorus starvation release iron-chelating molecules. Considering the geochemical interaction between these two elements, the authors suggest that some bacteria can dissolve iron-containing minerals in order to access the adsorbed phosphate.[6]
^Park, J. H., Bolan, N., Megharaj, M., & Naidu, R. (2011). Isolation of phosphate solubilizing bacteria and their potential for lead immobilization in soil. Journal of hazardous materials, 185(2), 829-836.
Mahamuni, S. V. and Patil, A.S. (2012). Microbial Consortium Treatment to Distillery Spent Wash and Press Mud Cake through Pit and Windrow System of Composting. Journal of Chemical, Biological and Physical Sciences. 2(2):847-855.
