Phosphate solubilizing bacteria
Encyclopedia
Phosphate solubilizing Bacteria (PSB) are a group of beneficial bacteria capable of hydrolysing organic and inorganic phosphorus from insoluble compounds. P-solubilization ability of the microorganisms is considered to be one of the most important traits associated with plant phosphate nutrition. It is generally accepted that the mechanism of mineral phosphate solubilization by PSB strains is associated with the release of low molecular weight organic acids,through which their hydroxyl
and carboxyl groups chelate the cations bound to phosphate, thereby converting it into soluble forms.In addition, some PSB produce phosphatase like phytase
that hydrolyse organic forms of phosphate compounds efficiently. One or both types of PSB have been introduced to Agricultural community as phosphate Biofertilizer
. Phosphorus (P) is one of the major essential macronutrients for plants and is applied to soil in the form of phosphate fertilizers. However, a large portion of soluble inorganic phosphate which is applied to the soil as chemical fertilizer is immobilized rapidly and becomes unavailable to plants . Currently, the main purpose in managing soil phosphorus is to optimize crop production and minimize P loss from soils. PSB have attracted the attention of agriculturists as soil inoculums to improve the plant growth and yield. When PSB used with rock phosphate, it can save about 50% of the crop requirement of phosphatic fertilizer. The use of PSB as inoculants increases the 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. Currently, different strains of these bacteria has been identified for using in biofertilizer
, of all, three new strains
Pantoea agglomerans
strain (P5), Microbacterium laevaniformans strain (P7) and Pseudomonas putida
strain (P13) has been recently identified as the highly efficient insoluble phosphate solubilizer.
Hydroxyl
A hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...
and carboxyl groups chelate the cations bound to phosphate, thereby converting it into soluble forms.In addition, some PSB produce phosphatase like phytase
Phytase
A phytase is any type of phosphatase enzyme that catalyzes the hydrolysis of phytic acid --an undigestible, organic form of phosphorus that is found in grains and oil seeds-- and releases a usable form of inorganic phosphorus...
that hydrolyse organic forms of phosphate compounds efficiently. One or both types of PSB have been introduced to Agricultural community as phosphate Biofertilizer
Biofertilizer
A bio-fertilizer is a substance which contains living microorganisms which, when applied to seed, plant surfaces, or soil, colonizes the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant.Bio-fertilizers add...
. Phosphorus (P) is one of the major essential macronutrients for plants and is applied to soil in the form of phosphate fertilizers. However, a large portion of soluble inorganic phosphate which is applied to the soil as chemical fertilizer is immobilized rapidly and becomes unavailable to plants . Currently, the main purpose in managing soil phosphorus is to optimize crop production and minimize P loss from soils. PSB have attracted the attention of agriculturists as soil inoculums to improve the plant growth and yield. When PSB used with rock phosphate, it can save about 50% of the crop requirement of phosphatic fertilizer. The use of PSB as inoculants increases the 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. Currently, different strains of these bacteria has been identified for using in biofertilizer
Biofertilizer
A bio-fertilizer is a substance which contains living microorganisms which, when applied to seed, plant surfaces, or soil, colonizes the rhizosphere or the interior of the plant and promotes growth by increasing the supply or availability of primary nutrients to the host plant.Bio-fertilizers add...
, of all, three new strains
Strain (biology)
In biology, a strain is a low-level taxonomic rank used in three related ways.-Microbiology and virology:A strain is a genetic variant or subtype of a micro-organism . For example, a "flu strain" is a certain biological form of the influenza or "flu" virus...
Pantoea agglomerans
Pantoea agglomerans
Pantoea agglomerans is a Gram-negative bacterium that belongs to the family Enterobacteriaceae.Formerly called Enterobacter agglomerans, this bacterium is known to be an opportunistic pathogen in the immunocompromised, causing wound, blood, and urinary-tract infections. It is commonly isolated...
strain (P5), Microbacterium laevaniformans strain (P7) and Pseudomonas putida
Pseudomonas putida
Pseudomonas putida is a gram-negative rod-shaped saprotrophic soil bacterium. Based on 16S rRNA analysis, P. putida has been placed in the P. putida group, to which it lends its name....
strain (P13) has been recently identified as the highly efficient insoluble phosphate solubilizer.