“Isolation and Characterization of Phosphofungi – Aspergillus niger from Rhizosphere Soil to supplement Phospho-biofertilizer”

Abstract In the present study, the phosphate-solubilizing fungus was isolated and identified as Aspergillus niger. Its 18S rRNA gene sequence was deposited at GenBank, NCBI (MN904862). For the study of the Phosphate solubilization capacity of the fungus, different rhizosphere soil samples were collected from medicinal plants. 40 fungal colonies were isolated after serial dilution and one fungal colony with high phosphate solubilization zone was selected and further tested. The fungus showed good results in different phosphate solubilization tests, SI (3.91), SE (290), and pH of the culture filtrate after the growth of the fungus decreased from 6.89 to 3.13 due to the production of organic acids. The colour changed from blue to yellow on the agar plate and red to yellow in the broth due to the acidic condition of the media during the growth of the fungus. Titrable acidity was measured at 32.8g/L and 420µg of P was estimated in culture broth by the Vanadomolybdate method. The fungus showed a positive result for siderophore production. 20µg of Indole Acetic Acid (IAA) was produced by the fungus and was estimated by the Salkowaski reagent method using a standard calibration curve. Due to the phosphate solubilization capacity and production of plant growth promoters of A. niger, can be recommended as a Phosphate solubilizer in an agricultural field.