Strain Improvement of Phosphate Solubilizers by Random Mutagenesis

Phosphate solubilizing microorganisms were isolated from rhizosphere soils of rice fields Tiruchirappali district of Tamilnadu. The isolated cultures were identified as Pseudomonas sp, Aspergillus niger, Aspergillus fumigatus and Penicillium sp. The efficacy of phosphate solubilization, Phosphatase, Lipase activity and Indole acetic acid production assay of isolated strains were carried out. The isolated strains were subjected to random mutational studies. The phosphate solubilization, Phosphatase, Lipase activity and Indole acid production were carried out after random mutagenesis by using wild and mutated cultures. Phosphate solubilization efficacy of the wild strains was higher in fungi when compared to bacteria. The phosphate solubilization efficacy and Phosphatase activity of the wild strains was observed in the order of A.niger >Penicillium sp. > A.fumigatus. ANems120 showed the highest phosphate solubilization activity among all chemical mutated fungal strains.ANsa120 was the predominant fungal strain for Phosphatase activity. The PSems120 was the predominant Lipase producing strain. All the strains except A.fumigatus have the ability to produce the plant hormone IAA.