Phosphorus is one of the most important elements required by plants and it has many different roles, including energy production and transfer, increasing rooting, grain production and improving the quantity and quality of agricultural products. Unfortunately, more than 70% of the phosphorus entering the soil through PHOSPHATE fertilizers is stabilized and removed from the accessibility of plants. Therefore, phosphorus stabilization has caused the use of more chemical fertilizers and the amount of total phosphorus in the soil has increased and sometimes the entry of elements along with PHOSPHATE fertilizer may cause soil pollution. In order to increase the solubility of INSOLUBLE PHOSPHATEs in the soil or to prevent phosphorus stabilization, environmentally friendly PHOSPHATEsolubilizing microorganisms (PSM) such as bacteria, fungi, actinomycetes and algae can be employed. These microorganisms are able to convert INSOLUBLE inorganic and organic compounds of phosphorus into soluble compounds by various methods such as production of mineral and organic acids, proton production, and secretion of siderophore, chelation and production of phosphatase enzyme. In mineral soils containing large amounts of calcium, magnesium, iron and aluminum PHOSPHATEs, the production of mineral and organic acids and in organic soils the phosphatase enzymes are mostly effective. Genes encoding PHOSPHATE solubility have been isolated mainly from Erwiniaherbicola, Esherichia coli and Morgonellamorgani. Some of these genes include ushA, agp, cpdB and napA. Despite the existing problems, fortunately, good progress has been made in the field of genetic engineering of PHOSPHATE-solubilizing microorganisms so that PHOSPHATE-solubilizing genes can be transferred to other bacteria. Due to the fact that soils contain both inorganic and organic compounds, it is recommended to use a microorganism with the ability to dissolve both organic and mineral compounds and a mixture of some microorganisms.

Rhizosphere is the living habitat for a variety of microorganisms, especially bacteria which may have beneficial, detrimental or neutral effects on plant growth. Rhizosphere beneficial bacteria are commonly called plant growth promoting rhizobacteria (PGPR) and have been under researchers focus for many years. PGPRs can stimulate plant growth through different mechanisms. Solubilization of inorganic PHOSPHATE is a characteristic has been frequently used for screening these bacteria. Flavobacterium has been noted as PGPR in almost all review article as well. In this research forty-four isolates of Flavobacterium were isolated from wheat rhizosphere in Iran and their ability for solobilizing inorganic PHOSPHATE in solid and broth medium was determined. Results of the PHOSPHATE solubilizing in solid medium revealed that twenty-eight isolates were capable to growth in solid medium. PHOSPHATE solubilizing index ranging from 0.24-1.17, 0.15-1.36 and 0.12- 2.73 after 4, 6 and 8 days after inoculation. Isolate F11 was selected as a superior isolate. Thirty-four isolates were capable to solubilizing inorganic PHOSPHATE in broth medium. The average rate of P-solublization was 3.54mg/ml, ranging from zero to 37.48. The result showed that F11 was superior isolate.

Phosphorus plays a crucial role in aquatic ecosystems, serving as a vital nutrient that promotes the growth and enrichment of freshwater environments, particularly in warm-water fish ponds. It exists in various forms within aquatic systems, both soluble and INSOLUBLE. Cyanobacteria, a diverse group of oxygen-producing, photosynthetic prokaryotes, possess phosphatase activities that convert phosphorus into a soluble form. Thus, this study aimed to isolate, identify, and examine the phosphorus-dissolving capabilities of cyanobacteria found in fish culture ponds at a laboratory scale. The study evaluated the phosphorus dissolution efficiency of four cyanobacterial strains isolated from warm-water fish ponds: Chroococcus sp., Oscillatoria sp., Microcystis sp., and Gloeocapsa sp., using two phosphorus sources, tricalcium PHOSPHATE and calcium phytate, in both floating surface and biomass portions. The findings indicated that Microcystis sp. was particularly effective, dissolving 47.5 mg/liter of tricalcium PHOSPHATE and 67.3 mg/liter of calcium phytate in the floating portion. In the biomass, Gloeocapsa sp. demonstrated the highest efficiency in dissolving phosphorus from both tricalcium PHOSPHATE and calcium phytate, with concentrations of 35.5 mg/liter and 18.7 mg/liter, respectively. However, the study observed no significant difference in cyanobacterial growth under varying phosphorus concentrations and sources across the experimental groups. The research highlights that certain cyanobacteria isolated from fish culture ponds possess the capacity to dissolve phosphorus to a notable extent when provided with sufficient sources of INSOLUBLE phosphorus.

Introduction: Phosphorus and potassium are major essential macronutrients for biological growth and development. Application of soil microorganisms is one approach to enhance crop growth. Some bacteria are efficient in releasing K and solubilizing P from mineral sources but their behavior was not studied more in presence together.Materials and methods: In this study the ability of seven bacterial strains, including Pseudomonas putida P13, P. putida Tabriz, P. fluorescens Tabriz, P. fluorescens Chao, Pantoea agglomerans P5, Azotobacter sp. and Bacillus megaterium JK3 to release mineral K from muscovite and biotite with application of INSOLUBLE (Ca3(PO4)2) or soluble (Na2HPO4) P-sources was investigated. Nutrient Broth was used to prepare an overnight culture of bacteria to inoculate in Aleksandrov medium, which was used to study the dissolution of silicate minerals. It should be mentioned that Aleksandrov medium was used to determine the amount of released P from tricalcium PHOSPHATE (TCP) while muscovite was added to the medium as a sole source of potassium. Concentration of P was determined spectrophotometric ally by ammonium-vanadate-molybdate method and K was determined by flame photometry.Results: The INSOLUBLE P-source led to a significantly increased released K into assay medium (66%), and the net release of K from the biotite was significantly enhanced. Among bacterial strains, the highest mean of released K was observed with P. putida P13 which released more K (27%) than the control. The amounts of released K from micas in the presence of INSOLUBLE and soluble PHOSPHATE by P. putida P13 were 8.25 and 4.87 mg/g, respectively.Discussion and conclusion: Application of INSOLUBLE PHOSPHATE could increase K release from mica minerals. The enhanced releasing of mineral K might be attributed to the release of organic acids from the bacteria, a mechanism which plays a pivotal role in solubilizing PHOSPHATE from inorganic source of PHOSPHATE.

This research aims to isolate phosphorus-solubilizing fungi from the sediments of warm-water fish farms and evaluate their performance in phosphorus solubilizing from various INSOLUBLE sources of phosphorus (tricalcium PHOSPHATE, iron PHOSPHATE, aluminum PHOSPHATE, and calcium phytate). For this purpose, four stations in Mazandaran province were sampled and isolated using NBRIP solid culture medium (49 mushroom isolates, including 19 isolates from organic phosphorus-containing culture medium and 30 isolates from inorganic phosphorus-containing culture medium). Then, the ability of isolates to dissolve phosphorus in solid and liquid culture medium was evaluated. Among the isolates, isolates PS3D, PS3F, and PS5F had the best performance among isolates solubilizing organic phosphorus (average phosphorus release 179.85-191.08 mg/liter). TS4E isolate was also selected as the best inorganic phosphorus solubilizing isolate. Then these isolates were molecularly identified by S18 rDNA gene sequencing and were registered as Talaromyces austrocalifornicus (PS3D), Trichoderma harzianum (PS3F), Aspergillus niger (PS5F) and Penicillium oxalicum (TS4E). In the final stage, the ability of these isolates to dissolve phosphorus in microcosm conditions (water and sediment-containing jars) was evaluated for 15 days. Contrary to the performance of these fungi in a liquid culture medium, the amount of soluble phosphorus in microcosm conditions showed a decreasing trend compared to day zero. However, the amount of phosphorus in the treatments containing mushrooms was higher than the control group. In general, the performance of the fungi introduced in this study has been positive in phosphorus release.

Co-application of biological fertilizers and PHOSPHATE sources have greatly considered in calcareous soils in recent years. In order to study the effect of PHOSPHATE solubilizing bacterium (PSB), PHOSPHATE sources and vermicompost on some growth characteristics of lettuce (cv. Ferdos), a greenhouse experiment was conducted with factorial arrangement in a completely randomized design with three replications and three factors. Factors consisted of two levels of PHOSPHATE solubilizing bacterium (Pseudomonas flouresence) (with and without inoculation), two levels of vermicompost (0 and 1% w/w) and four PHOSPHATE sources (control, rock PHOSPHATE, tricalcium PHOSPHATE (TCP) and triple super PHOSPHATE at 25 mg P kg-1 soil). Biological fertilizers significantly increased shoot fresh and dry weights (SFDW), but they didn’t have remarkable effect on lettuce height. Application of rock PHOSPHATE and tricalcium PHOSPHATE (TCP) increased dry and fresh weight, respectively. Application of triple super PHOSPHATE significantly increased SFDW and lettuce height. Co-application treatments of bacterium, vermicompost and PHOSPHATE sources (except super PHOSPHATE) significantly increased SFDW, leave numbers and phosphorus concentration of lettuce. Overall, the results indicated that phosphorus chemical fertilizers can be replaced by co-application of INSOLUBLE PHOSPHATE and biological fertilizers.

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.

In order to investigate P acquisition efficiency (PACE) and P utilization efficiency (PUTE) of the corn in the presence of PHOSPHATE-solubilizing microorganisms (PSMs), a factorial experiment was carried out in a completely randomized design in the greenhouse. The factors were including P sources (tricalcium PHOSPHATE (TCP) and rock PHOSPHATE (RP)) and microbial inoculation (control, soluble P as KH2PO4 (Ps), inoculation with bacteria (PSB), inoculation with fungi (PSF), co-inoculation of PSB + PSF). At the end of growth period, plant dry weight and P content in plant and soil available-P were measured and then PACE, PUTE and phosphorus efficiency (PE) indices were calculated. The results showed that, the interaction of PHOSPHATE source and microbial inoculation was significant with respect to shoot P content, soil P, PUTE and PE. PSF-TCP treatment increased 7 times shoot phosphorus content compared to cont-RP treatment. PUTE in Cont-TCP treatment was 2. 35 times higher than the TCP-PS. The inoculation of PSF increased the PACE 1. 61 times compared to co-inoculation of PSB + PSF tretment. Also, the highest PE index (99%) was obtained from SF-TCP treatment. In general, in calcareous soils with low P availability, inoculation of PSM with INSOLUBLE phosphorus sources can meet the PHOSPHATE needs of the plant...

In lecithin production unit of Jahan Vegetable Oil Co. (JVOC), Karaj, Iran, studies are made for the lecithin produced by hexane extracted soybean oil, with the standard specification (except for hexane-INSOLUBLE (HI) materials), which is above 0.3% in crude lecithin. HI materials in lecithin are detrimental to clarity as it can cause haziness in fluid lecithin and usability in specific application. Analyses of crude oil before and after filtration indicated that filter plates do not effect lyre move of the impurities of residual fines, seed fragments and metal particles. Crude oil has more HI materials during degumming than before degumming. Analyses of oil and lecithin during processing steps showed increase in HI and toluene-INSOLUBLE (TI) materials where ever water was added. Degumming water contained about 360-1330 ppm salt (T.S), which contributed to the HI mateials. About 30- 38% of HI are salt and the rest are water-soluble most probably sugar. Salt free water and efficient filtration of oil, as tested in laboratory degumming process, decreased the HI matters in lecithin to below 0.3%.

Beneficial soil microorganisms protect the plant from stress by forming symbiotic relationships with the plant, and by converting and retaining elements in the soil, they feed the plant. This research was carried out in two parts: 1) isolation and purification of Fifty-five halophilic, alkaliphilic, and haloalkaliphilic isolates from different almond (Prunus amygdalus L. ) rhizosphere soils in Khorasan Razavi province and investigation of some plant growth-enhancing properties in all isolates in the laboratory conditions to select superiors isolates, 2) test of the six best-selected isolates in the vicinity of the GN15 almond rootstocks to evaluate the effect of the isolates on the availability of phosphorus, potassium, iron, zinc, chlorine and sodium ions in four saline-sodic soils (2, 4, 8 and 16 dS m-1 salinity, and 9. 69, 14. 99, 14. 21 and 19. 72 SAR respectively). The results showed that the average production of plant growth-enhancing properties for alkaliphilic, haloalkaliphilic and halophilic isolates wasfor the production of indole-3-acetic acid (213. 93, 77. 13 and 15. 98 mg L-1 ), the solubility of mineral PHOSPHATEs (127. 55, 73. 99 and 40. 19 mg L-1 ) and the production of exopolysaccharides (578. 11, 284. 54 and 35. 90 mg L-1 ). The use of bacteria stabilized the pH in the range of 7 to 7. 5 and significantly reduced soil electrical conductivity at high salinities (8 and 16 dS m-1 ) and increased exopolysaccharides. The highest concentration of phosphorus and chlorine anions in soil was observed in alkaliphilic bacteria treatment, the highest concentrations of soil potassium, iron, zinc, and sodium were affected by halophilic bacteria. The highest ratio of K/Na in soil was obtained in the treatment of halophilic (15. 3), alkaliphilic (11. 8), and haloalkaliphilic (9. 4) bacteria, respectively. All kinds of indigenous bacteria of halo-alkaliphilic bacteria showed more efficiency in converting and maintaining nutrients in salinity more than 8 dS m-1 and SAR higher than 15.