Phosphate solubilisation and organic acid production by some species of Aspergillus

Forty species of Aspergillus screened for phosphate solubilization showed their activity to various extents. A. sparsus and 4 members of the Niger group, namely, A. carbonarius, A. tubingensis, A. aculeatus and A. japonicus were found to be highly active. Production of organic acids being the key mechanism in solubilization of phosphates the species were also screened for production of organic acids. Every species showed production of one organic acid or the other. Malic acid was produced by all the isolates. Other common acids produced were acetic acid, fumaric acid and citric acid. GCMS results of the culture filtrates of the black Aspergilli (Niger group) confirmed the production of organic acids by the members of this group.