Optimization of various culture conditions for phosphate solubilization by Burkholderia latens isolated from Bt-cotton rhizospheric soil

Abstract

Phosphate solubilizing microbes possess the characteristic to convert the fixed form of phosphorus to available form for plants to absorb phosphorus from soil. Phosphorus is essential for storage and transfer of energy, photosynthesis as well as biochemical and genetic activities of plant. Various culture conditions like incubation time, inoculum size, temperature, pH, phosphate sources, carbon sources, nitrogen sources, tricalcium phosphate (TCP) concentration and glucose concentration were optimized to obtain maximum phosphate solubilization by Burkholderia latens isolated from Bt-cotton rhizospheric soil. Phosphate solubilizing efficiency of Burkholderia latens was tested in PVK media with 0.5% tricalcium phosphate as phosphate substrate. Burkholderia latens showed maximum phosphate solubilization at 7.5 pH of the medium incubated with 3% of inoculum size for 3 day incubation at 32 oC temperature. Burkholderia latens showed maximum phosphate solubilization medium containing 2.5% of glucose as a sole source of carbon, (NH4)2 SO4 as a nitrogen source and 0.5 % of tricalcium phosphate (TCP) as phosphate source. Burkholderia latens showed 328.7 ± 7.13 μg mL-1 of phosphate solubilization under unoptimized condition.