Journal of Pure and Applied MicrobiologyVol. 1 No. 2

Isolation of Tri-calcium Phosphate Solubilizing Bacterial Strains from Semi-arid Agricultural Soils of Rajasthan, India.

Anamika, Jyoti Saxena and Vinay Sharma*

Department of Bioscience and Biotechnology, Banasthali Vidyapith, Banasthali - 304 022, India.

Received on 01 July 2007 and accepted on 26 July 2007



The present study deals with the isolation and in vitro activity of tri-calcium phosphate (TCP) solubilizing bacteria. Bacterial strains were isolated by serial dilution and enrichment methods from the rhizosphere of green gram, sesame and pearl millet cultivated soil and from the non-rhizosphere. The rhizosphere of these plants inhabited with diversified and larger bacterial population than those of non-rhizosphere soil. Enrichment method yielded a high percentage (ca.79%) of TCP solubilizing bacteria than serial dilution method (ca. 44%). Total 83 bacterial isolates were obtained from different soil samples on the basis of colony morphology, Gram’s reaction and zone of P- solubilization on Pikovskaya’s agar plates. P- solubilization activity of these bacterial isolates was determined at 300C upto 5 days in Pikovskaya’s broth. They solubilized 7.6-13.5% of the TCP supplied in the medium. The phosphate analysis of selected soils showed low to medium amount of available P (1.12 Kg ha-1 – 20.71 Kg ha-1). On the basis of P- solubilization efficiency within the first 24 hours of inoculation we selected ten most efficient strains, which may possibly be used as biofertilizers in P poor soils in arid and semi-arid areas such as Rajasthan.

Keywords : Phosphate solubilizing bacteria, tri-calcium phosphate, Pikovskaya’s broth, Rhizosphere.