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Aims: Heavy metals are one of the most important pollutants in earth and water environments due to long-term durability. The aim of this study was to isolate phosphate solubilizing bacteria from metal waste, investigate the amount of resistance, remove the metal by it and the effect of phosphatase on removal of metals.
Materials & Methods: In this experimental study, the isolation of phosphate solubilizing bacteria and detection of isolates were carried out, using biochemical and molecular tests. The phosphatase was measured by colorimetric method, the resistance of the separated to the metals with the minimum inhibitory concentration (MIC₅₀), minimum bactericidal concentration (MBC) and the rate of removal of metals by atomic absorption was measured. The surface changes of the exposed metal cells were investigated by Fourier Transform Infrared Spectroscopy (FTIR) and the effect of phosphatase on metal removal. Data analysis was done with Duncan's test, using Excel 2013 and SPSS 20 software.
Findings: Serratia proteamaculans was identified as producer of the acid phosphatase. The highest MIC and MBC were obtained for Nickel (Ni) and Lead (Pb), respectively. The most metal removal was for Pb. MIC₅₀ of Chrome and Cadmium were obtained less than 0.1mM and 1mM, and their removal percentage by the isolate were 18% and 48%, respectively. According to the FTIR, 988.339cm^-1 wavelength was observed in the cells treated by 5mM Pb that is related to the Pb₃(PO₄)₂. The isolate showed the highest resistance and removal of Pb. The mechanism of Ni removal was associated to the cell surface, while Pb was removed by both of the cells and supernatant containing phosphatase.
Conclusion: Serratia proteamaculans is the phosphate solubilizing bacterium in metal waste. This bacterium produces an enzyme called phosphatase, which is a cause of lead removal.

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The aim of the present study was to investigate the possibility of replacing phosphorus chemical fertilizer (triple superphosphate) with biofertilizers as an environmentally friendly approach.  In this study, Possibility of replacing Triple superphosphate fertilizer with phosphate solubilizing bacteria "Pseudomonas deceptionensis Persian10 strain" in 10 treatments with two bacterial factors (in two levels of inoculation and non-inoculation) and chemical fertilizer (in five levels 0, 25, 50, 75 and 100% of the recommended amount of fertilizer in the pond) was examined in aquarium conditions. Treatments included: 1: 100% fertilizer + bacteria, 2: bacteria, 3: 25% fertilizer + bacteria, 4: 50% fertilizer + bacteria, 5: 75% fertilizer + bacteria, 6: 100% fertilizer, 7: 75% fertilizer, 8: 50% fertilizer, 9: 25% fertilizer, 10: control (without fertilizer and bacteria). Bacterial densities, soluble phosphorus, phosphatase and pH were measured on days 0, 2, 7, 12 and 17. The results showed that the phosphorus of all treatments had an increasing trend on different days and at the same time, an increase in the pH value and a decreasing trend was observed in the bacterial population and the amount of phosphatase enzyme. The highest amount of soluble phosphorus was observed in treatments 4 and 5. According to the obtained results, the application of 50% phosphate fertilizer + phosphate solubilizing bacteria can be recommended as a suitable ratio for the fertility of fish ponds and reducing the use of chemical fertilizers.

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Native phosphate solubilizing bacteria (PSB) were isolated from four areas (Ankober, Keyt, Mehalmeda and Molale) of Ethiopia to study their effect on releases of soluble phosphorus from insoluble P sources. The highest bacterial number was found at Keyt (2.6103 g-1soil) and the least at Molale (15 g-1soil). Five efficient PSB were selected for further study based on their ability in forming a higher clear zone diameter than the other isolates. These isolates were identified based on phenotypic characters as Pseudomonas sp. Anb-105, Meh-008, Meh-101, Meh-303 and Meh-305. The phosphate solubilizing efficiency of these five isolates along with Jim-41 isolate from the National Soil Research Centre were studied using different P sources [Tricalcium Phosphate (TCP), Egyptian Rock Phosphate (ERP), Bikilal Rock Phosphate (BRP) and Old Bone meal (OB)] in an incubation study. The results revealed that all the PSB isolates significantly (P 0.01) solubilized a higher amount of TCP, ERP and OB over the uninoculated control. The highest amount of solubilization was achieved for TCP with Meh-305 (39 mg per 50 ml) followed by ERP with Meh-101 (31 mg per 50ml) at pH 3.82 and 3, respectively. Although Meh-008 and Jim-41 isolates solubilized significant amount of BRP during the 20 days of incubation, the soluble P obtained was very small as compared to other P source tested.

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An experiment was conducted at Assossa Agricultural Research Center (AARC) station during 2008 cropping season in order to study the effects of co-inoculation of Bradyrhizobium japonicum (TAL-378 and TAL-379) and phosphate-solubilizing bacteria (PSB) (Pseudomonas spp.), and conventional farmers’ fertilizer level (combined and individual application of 46N kg ha-1 and 46 P2O5 kg ha-1) on nodulation, seed yield and yield components of soybean (Glycine max L. (Merr.)). Analyses of variance indicated that most of the parameters measured were significantly (P>0.05) affected by the treatments. Accordingly, dual inoculation with TAL-378 and PSB significantly increased plant height at harvest, number of nodules per plant, nodule volume per plant, nodule fresh weight per plant, and shoot height at late flowering and early pod setting compared to the other treatments. Similarly, co-inoculation with TAL-378 and PSB, and dual fertilization of nitrogen (N) and phosphorus (P) fertilizers significantly increased number of pods per plant, number of seeds per pod per plant and seed yield ha-1 compared to the other treatments. Analysis of plant tissue also indicated that dual inoculation of TAL-379 and PSB yielded the highest total N whereas the lowest was recorded for the negative control. Likewise, dual inoculation with TAL-378 and PSB and the positive control gave the highest plant P compared to all other treatments. The data revealed that, there was no significant difference (P>0.05) in days required for emergence, flower bearing and maturity, number of seeds per pod, 300 seeds weight and root length among the investigated treatments. Thus, the dual inoculation of TAL-378 and PSB is recommended to achieve maximum seed yield of soybean in Assossa area.