Vol. 1, Issue 2, Part A (2019)

The present experiment is conducted on ‘isolation, Occurrence, Screening & Characterization of Rock phosphate solubilizing Microbes’. Phosphorus is the least mobile element in plant and soil contrary to other macronutrients. It precipitates in soil as orthophosphate or is absorbed by Fe and Al oxides through legend exchange. Phosphorus solubilizing bacteria play role in phosphorus nutrition by enhancing its availability to plants through release from inorganic and organic soil P pools by solubilization and mineralization Rock Phosphate is the cheapest and abundant Phosphatic fertilizer available but due to its sparse solubility. Most agricultural soils contain large reserves of phosphorus (P), a considerable part of which accumulates as a consequence of regular applications of P fertilizers. However, a greater part of soil phosphorus, approximately 95–99% is present in the form of insoluble phosphates and hence cannot be utilized by the plants combined application of rock phosphate with phosphate solubilizing microorganisms has emerged as a logical solution to this issue. The selection of microorganisms capable of solubilizing phosphorus (P) from rock phosphates (RP) may contribute to reduce the dependence of imported fertilizers in grain crops, reducing the costs of agricultural production, and also the environmental impacts. Principal mechanism in soil for mineral phosphate solubilization is lowering of soil pH by microbial production of organic acids and mineralization of organic P by acid phosphatase. Use of phosphorus solubilizing bacteria as inoculants increases P uptake. These bacteria also increase prospects of using phosphatic rocks in crop production. Greater efficiency of P solubilizing bacteria has been shown through co-inoculation with other beneficial bacteria and mycorrhiza In the present study bacterial and fungal strains were isolated from waste water, soil and sediment sample of ETP of Paradeep phosphate limited (PPL) and from Mahanadi river estuary (Paradeep), having potential to solubilize insoluble inorganic phosphates were characterized. Each isolates were tested for their tricalcium phosphate (TCP) and low grade rock phosphate (RP) solubilization efficiency in both solid and liquid medium. From the experiment it is found that out of 22 fungal isolates more than 50% were classified as efficient. There were significant differences in the availability of P among strains. From the Experiment it is also revealed that the solubilizing activity of both phosphates was associated with a reduction of pH which suggests that the acidification of the culture medium can be one of the mechanisms involved in the solubilization of P. Total number of 27 bacterial strains and 29fungal strains are taken for experiment and studied for maximum solubilization of insoluble inorganic phosphorous.. From the above study, it is concluded that More than 40% isolates of bacterial and fungal strains show the effect of phosphate solubilizing activity. The bacterial strain with 11B and fungal strain with 6F has highest phosphorous solubilization. From the maximum specific growth rate it can be concluded that the microbial isolates 6F and 11B are copiotrophs.