Abstract

This study presents insights into the screening, morphological and biochemical properties of some phosphate solubilizing microorganisms, which are organisms that can solubilize these fixed forms of phosphorus and make it available to plants.  A total of 27 Phosphate Solubilizing Microbial colonies were isolated on Pikovskaya agar medium, containing insoluble tricalcium phosphate (TCP) from agricultural soil. Out of 27 microbial isolates, 3 isolates, with the highest Phosphate Solubilization Index (PSI), ranging from 1.25 + 0.0 – 3.22 + 0.1 and highest phosphate solubilization efficiency (PSE), ranging from 98.0 + 1.01µg/ml to 239.0 + 1.0µg/ml from day 4 to day 12, were selected for further studies. These isolates psb1, psb4 and psb7 belong to the genus   Enterobacter, Alcaligenes and Clostridium, as identified by their morphological and biochemical properties respectively. There was a significant difference in the total viable count (log10 cfu/ml) for all the three isolates. Enterobacter sp. had significantly more cells, ranging from 1.57+ 1.0 on day 5 to 2.98 + 0.2 on day 7. Next in order of magnitude was Alcaligene sp. with a total viable count of 8.3 + 0.2 on day 5 to 2.00 +0.3 on day 7. This was followed by Clostridium sp. with a mean viable count of 7.2+ 0.0 on day 5 to 1.96 + 0.0 on day 7. This serves as a foundation for future exploration of the bio-prospective potential of rhizosphere bacteria in this unique ecological niche. Further assessment of these isolates is essential to determine their efficacy as potent PGPR agents.

Key Words:Phosphate Solubilizing Microorganisms, Phosphorus, Pikovskaya, Bacillus, Pseudomonas, Aspergillus