Phosphate solubilization by fungi isolated from alkaline soils

A phosphate solubilizing fungus, Aspergillus awamori S36, was isolated from the rhizosphere soil of Sesamum indicum grown in semi-arid climatic conditions. The organism was able to solubilize various inorganic forms of phosphate at a wide range of temperatures. Amongst various insoluble phosphate sources tested, di-calcium phosphate (DCP) was solubilized the most, followed by tri-calcium phosphate (TCP). The solubilization was evident at all the temperatures but the performance was especially good in the range of 25-35 degrees C. Phosphate-solubilizing ability was also measured in the presence of various carbon and nitrogen sources. Fructose was found to be the best carbon source, followed by maltose, glucose, whereas, amongst nitrogen sources, sodium nitrate supported maximum solubilization, followed by ammonium sulphate.