Isolation of Phosphorus-Solubilizing Fungus from Soil to Supplement Biofertilizer

Abstract

A number of bacterial and fungal isolates from soil were screened for phosphorus solubilization. One fungal strain was found to be efficient phosphorus solubilizer in Pikovskaya medium. The selected strain was identified as Aspergillus niger based on morphological and microscopic studies. Some important cultural conditions were optimized, and optimal conditions for temperature, glucose, ammonium sulfate and pH were found \({30^{\circ}{\rm C}}\), 20, 2 and 5 g/L, respectively, in 48 h of incubation. The fungal strain produces organic acids as well as phosphatases and phytases that make the medium clear within 48 h by solubilizing the added tricalcium phosphate. The soluble phosphorus concentration of medium decreased after 48 h of incubation, possibly due to the consumption of phosphorus by the fungal mycelium itself.