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

Abstract

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 7 th day was maximum of 321.7 µg/ml which was the highest value compared to other PSB isolates.

Nano-carriers effects on the viability and efficiency of Pseudomonas strains as phosphate solubilizing bacteria

“…The highest solubilizing indices for PK11 and PP20 were 2.935 and 2.870 both observed within the nanoclay + alginate carrier. Previous reports have revealed that the maximum and minimum colony diameter were found with Bacillus species P6 (1.91 mm) and P8 (0.61 mm), which also had the maximum and minimum of halo zone diameters of 5.89 mm and 2.1 mm, respectively ( Gandhi et al., 2014 ). The solubilizing efficiency of two Pseudomonas species (P1 and P2) among different organisms were reported to be 44.44 and 71.43% ( Selvi et al., 2017 ).…”

“…Inoculated plates were incubated in dark at 28 °C and the diameter of the clear zone (halo) and the bacterial growth diameter were measured after 8 days. All assays were replicated three times and solubilization index (SI) calculated by the following formula: SI = Colony diameter + Halo zone diameter/Colony diameter ( Gandhi et al., 2014 ) …”

“…Inoculated plates were incubated in dark at 28 C and the diameter of the clear zone (halo) and the bacterial growth diameter were measured after 8 days. All assays were replicated three times and solubilization index (SI) calculated by the following formula: (Gandhi et al, 2014) 2.5. Phosphatase activity P-nitrophenyl phosphate disodium (PNPP, 0.115 M) was used as a substrate in determining phosphatase activity.…”

Isolation and Screening of Potassium and Zinc Solubilizing Bacteria from Different Rhizosphere Soil

“…The zinc solubilizing bacterial isolates produce organic acid which help in solubilization of insoluble zinc compound. Similarly, Gandhi et al, (2014) isolated 240 zinc solubilizing bacterial strains from rhizosphere of rice. Based on the performance of bacterial strains, there were 15 isolates found to be potential zinc solubilizer.…”

Isolation of Phosphate Solubilizing Microorganism (PSM) from Reclaimed Fly Ash Zone of Mejia Thermal Power Station (MTPS) and its Implications

“…shape, size, elevation, colony structure, surface form, margins and surface texture or color; at 10 -4 , 10 -6 or 10 -8 dilution spreading were noted down and observed for their characterization. [37] …”