Isolation and Identification of Elite Phosphate Solubilizing Bacteria from Soil under Paddy Cultivation

A considerable number of bacterial species are able to exert a beneficial effect upon plant growth. Mostly they are associated with the plant rhizosphere, so they are called as rhizobacteria. Phosphorus is an essential element for plant development and growth making up about 0.2 % of plant dry weight. Several scientists have reported the ability of different bacterial species to solubilize insoluble inorganic phosphate compounds, such as tricalcium phosphate, dicalcium phosphate, hydroxyapatite, and rock phosphate. Detection and estimation of the phosphate solublization ability of microorganisms have been possible using plate screening methods. Phosphate solubilizers produce clearing zones around the microbial colonies in growth media. In the present investigation a total number of fifteen phosphate solubilizing bacterial colonies isolated from different paddy soils in Cuddalore district of Tamilnadu, India. The isolated PSB were identified and characterized for effective use in the field. All the PSB isolates were identified as Bacillus species and designated as P with serial number from 1 to 15. Among the fifteen isolates, the PSB isolate P6 showed highest amount of phosphate solubilization. The quantity of available phosphorus estimated in the P6 grown Sperber broth culture medium on 7th day was maximum of 321.7 μg/ml which was the highest value compared to other PSB isolates.