Phosphate Uptake Rates Research Articles

Comparison of phosphate uptake rates by the smallest plastidic and aplastidic protists in the North Atlantic subtropical gyre

The smallest phototrophic protists (<3 μm) are important primary producers in oligotrophic subtropical gyres - the Earth's largest ecosystems. In order to elucidate how these protists meet their inorganic nutrient requirements, we compared the phosphate uptake rates of plastidic and aplastidic protists in the phosphate-depleted subtropical and tropical North Atlantic (4-29°N) using a combination of radiotracers and flow cytometric sorting on two Atlantic Meridional Transect cruises. Plastidic protists were divided into two groups according to their size (<2 and 2-3 μm). Both groups of plastidic protists showed higher phosphate uptake rates per cell than the aplastidic protists. Although the phosphate uptake rates of protist cells were on average seven times (P<0.001) higher than those of bacterioplankton, the biomass-specific phosphate uptake rates of protists were one fourth to one twentieth of an average bacterioplankton cell. The unsustainably low biomass-specific phosphate uptake by both plastidic and aplastidic protists suggests the existence of a common alternative means of phosphorus acquisition - predation on phosphorus-rich bacterioplankton cells.

Innovative anaerobic/upflow sludge blanket filtration bioreactor for phosphorus removal from wastewater

Phosphorus is the key element to remove from aquatic environments to limit the growth of aquatic plants and algae and, thus, to control eutrophication. Because the upflow sludge blanket filtratio' (USBF) process, without addition of metal salts, entails low efficiency for phosphorus removal, we added an anaerobic reactor to the USBF bioreactor in order to promote the simultaneous removal of phosphorus and nitrogen from wastewater. The results revealed that the anaerobic/USBF bioreactor had a phosphorus removal efficiency up to 86%, with a sludge retention time (SRT) of 10 days, a hydraulic retention time (HRT) of 24 hours and an optimum COD/N/P ratio of 100/5/1. This ratio also improved the compaction quality of the sludge blanket in the USBF clarifier. The average specific phosphate uptake rate in the aerobic zone and the average specific phosphate release rate in the anaerobic reactor were 0.014 mg PO4‐P removed/(g VSS·min) and 0.0525 mg PO4‐P released/(g VSS·min), respectively. Secondary phosphorus release in the USBF clarifier was heightened with increasing HRT. Hence, the optimum total HRT can be selected between 16 and 24 hours based on effluent quality. Effluent phosphorus of about 1 mg/L was provided for wastewater with the COD/N/P ratio of 100/5/1 at the sludge age of 10 days and total HRT of 16 hours. This study illustrated that the anaerobic/USBF bioreactor at the optimum operational conditions can be an effective process for phosphorus removal from municipal wastewater.

Culturing of stoneworts and submersed angiosperms with phosphate uptake exclusively from an artificial sediment

Summary 1. We aimed to demonstrate reproducible nutrition and growth of macrophytes in non-axenic laboratory cultures preventing growth of phytoplankton and epiphytes. 2. Macrophyte shoot segments were planted in a mixture of commercial acid-washed silica sand with crystalline tricalcium phosphate, and this artificial sediment was covered with a layer of pure silica sand. The liquid mineral media used did not contain phosphorus but were rich in all other nutrient elements. A CO2 reservoir provided sustainable CO2 supply to macrophyte cultures by gas diffusion through a polyethylene membrane. 3. Chara hispida, Chara tomentosa, Chara baltica, Elodea canadensis, Potamogeton pectinatus and Zanichellia palustris could be cultivated for long term without medium exchange and aeration. Microalgae growth was prevented by the absence of phosphate in the water column. Mobilisation of tricalcium phosphate and phosphate uptake by the rhizoids of C. hispida enabled sustainable rapid shoot growth and increased the concentration of inorganic phosphate in the shoot dry weight by five to six times in comparison with plants cultivated on pure silica sand. A significant growth support from tricalcium phosphate was also observed for E. canadensis, but the rate of phosphate uptake by the roots was not sufficient to maintain a storage pool of inorganic phosphate (Pi) in the growing shoots of this plant. 4. Membrane-controlled CO2 supply from a reservoir and artificial sediments like the one described provide attractive options for the laboratory culture of macrophytes.

Co-precipitation of Phosphate and Iron Limits Mitochondrial Phosphate Availability in Saccharomyces cerevisiae Lacking the Yeast Frataxin Homologue (YFH1)

Saccharomyces cerevisiae cells lacking the yeast frataxin homologue (Δyfh1) accumulate iron in the mitochondria in the form of nanoparticles of ferric phosphate. The phosphate content of Δyfh1 mitochondria was higher than that of wild-type mitochondria, but the proportion of mitochondrial phosphate that was soluble was much lower in Δyfh1 cells. The rates of phosphate and iron uptake in vitro by isolated mitochondria were higher for Δyfh1 than wild-type mitochondria, and a significant proportion of the phosphate and iron rapidly became insoluble in the mitochondrial matrix, suggesting co-precipitation of these species after oxidation of iron by oxygen. Increasing the amount of phosphate in the medium decreased the amount of iron accumulated by Δyfh1 cells and improved their growth in an iron-dependent manner, and this effect was mostly transcriptional. Overexpressing the major mitochondrial phosphate carrier, MIR1, slightly increased the concentration of soluble mitochondrial phosphate and significantly improved various mitochondrial functions (cytochromes, [Fe-S] clusters, and respiration) in Δyfh1 cells. We conclude that in Δyfh1 cells, soluble phosphate is limiting, due to its co-precipitation with iron.

Phosphate and adenosine‐5'‐triphosphate uptake by cyanobacteria and heterotrophic bacteria in the Sargasso Sea

We used flow cytometry sorting to quantify assimilation of phosphate and adenosine‐59‐triphosphate (ATP) by heterotrophic bacteria and the cyanobacteria Prochlorococcus and Synechococcus during the fall of 2007 and 2008 and the spring of 2009 in the western Sargasso Sea. Phosphate and ATP uptake rates per cell were 50‐fold and 80‐fold higher, respectively, for Synechococcus than for the other two microbial groups, whereas there was no significant difference between ATP and phosphate uptake per cell by Prochlorococcus and heterotrophic bacteria. Both cyanobacterial groups had higher rates of phosphate uptake per surface area than did the heterotrophic bacteria; Synechococcus had the highest rates per cellular phosphorus (P)‐quota for ATP uptake, and Prochlorococcus usually had lower rates. Heterotrophic bacteria had the lowest uptake rates of ATP and phosphate per cellular P quota. In contrast, total uptake of phosphate and ATP per liter of seawater was dominated by heterotrophic bacteria, while uptake by Prochlorococcus and Synechococcus was less than 10% of the total, as a result of their low abundance (15% and 1.5% of total prokaryotes, respectively). Uptake rates of phosphate and ATP for heterotrophic bacteria and Prochlorococcus were less tightly coupled than for Synechococcus, and phosphate appeared to be favored over ATP for all three groups. Uptake rates of both compounds by Synechococcus were much higher than by the other microbial groups. Cyanobacteria are successful competitors for phosphate and ATP in the Sargasso Sea.

Nutrient removal performance in an intermittent aerated sequencing batch membrane bioreactor

In this study, a sequencing batch membrane bioreactor (SBMBR) was operated with intermittent aeration to perform partial nitrification nutrient removal. Several batch experiments were also carried out to investigate the nutrient removal characteristics. The removal efficiencies of suspended solid (SS), chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) for the SBMBR process were 96.7, 95.5, 73.6 and 98.1%, respectively. It was also found that all the organic‐ and ammonia‐nitrogen was nitrified into nitrite rather than nitrate form, showing partial nitrification. The results of the batch experiments showed that heterotrophic nitrification occurred and nitrite was still the predominant oxidized nitrogen species. It was also observed that autotrophic denitrification occurred during the denitrification batch experiments, although the autotrophic denitrification rate was only 34% of the heterotrophic denitrification rate. In addition, there was no significant difference in the phosphate uptake rate observed between nitrite and nitrate as electron acceptors. Finally, five nutrient removal related bacteria were identified in the SBMBR reactor using the pure culture method.

Denitrifying dephosphatation over nitrite: Effects of nitrite concentration, organic carbon, and pH

The effects of nitrite concentration, organic carbon and pH on denitrifying dephosphatation over nitrite were studied with batch tests. The results showed that anoxic initial phosphate uptake rate increased as nitrite concentration increased. For an initial phosphate of 8.5 mg P L −1 and an initial COD of 350 mg L −1, a nitrite level of 15.2 mg N (gMLSS) −1 was found to be appropriate. The anaerobic phosphate release rate decreased as anaerobic nitrite addition increased. The results suggest that to ensure effective phosphate release and subsequent phosphate uptake, anaerobic nitrite should be lower than 2 mg N L −1. Very high and very low initial COD concentrations both resulted in an adverse effect on denitrifying dephosphatation. The anaerobic phosphate release with different carbon sources followed the order: acetate > butyric acid > glucose. The suitable pH for anaerobic phosphate release and anoxic phosphate uptake was approximately 7.0 and 8.0, respectively.

A dynamic model of nutrient uptake by root hairs

Root hairs are known to be important in the uptake of sparingly soluble nutrients by plants, but quantitative understanding of their role in this is weak. This limits, for example, the breeding of more nutrient-efficient crop genotypes. We developed a mathematical model of nutrient transport and uptake in the root hair zone of single roots growing in soil or solution culture. Accounting for root hair geometry explicitly, we derived effective equations for the cumulative effect of root hair surfaces on uptake using the method of homogenization. Analysis of the model shows that, depending on the morphological and physiological properties of the root hairs, one of three different effective models applies. They describe situations where: (1) a concentration gradient dynamically develops within the root hair zone; (2) the effect of root hair uptake is negligibly small; or (3) phosphate in the root hair zone is taken up instantaneously. Furthermore, we show that the influence of root hairs on rates of phosphate uptake is one order of magnitude greater in soil than solution culture. The model provides a basis for quantifying the importance of root hair morphological and physiological properties in overall uptake, in order to design and interpret experiments in different circumstances.

Comparison between UCT type and DPAO biomass phosphorus removal efficiency under aerobic and anoxic conditions

Two different types of biomass, capable for Enhanced Biological Phosphorus Removal (EBPR), a UCT (University of Cape Town) type and a sludge enriched with DPAOs (Denitrifying Phosphorus Accumulating Organisms) were tested in batch reactors under specific operational and environmental conditions, in order to achieve a direct comparison of their phosphorus removal capability. Three types of batch reactors were operated, Anaerobic/Oxic (AO), Anaerobic/Anoxic (A2) and Anaerobic/Anoxic/Oxic (A2O), under controlled temperature and pH conditions. Maximum anaerobic specific phosphate release, substrate utilization, as well as denitrification and phosphate uptake rates under aerobic and anoxic conditions were determined and compared for the two different microbial populations. Experimental results indicated no significant difference between the anoxic and the aerobic phosphorus (P) uptake rates, respectively for DPAO and UCT sludge. The UCT sludge was also found to achieve anoxic P uptake, however to much less extend compared to the DPAO sludge. It has also been proved that anoxic P uptake seems to negatively affect the total P removal efficiency of this type of sludge, even under following aerobic conditions. Based on these findings, denitrifying phosphorus removal systems are proved comparable to conventional EBPR configurations (UCT), concerning phosphorus removal efficiency, while their operation is accompanied by potential advantages.

Optimization of biological nutrient removal in a pilot plant UCT-MBR treating municipal wastewater during start-up

This study shows that an MBR pilot plant with UCT configuration is able to obtain high nutrient removal efficiency already during start-up. The biological nutrient removal (BNR) efficiencies significantly increased towards the end of the experimental run, achieving a COD removal efficiency exceeding 94% and N removal efficiency in the range of 89 to 93%. P removal efficiencies in the range of 80 to 92% have been obtained. During the experimental period (4 months) the evolution of the activity of polyphosphate-accumulating organisms, obtained from P release and P uptake rates, showed a small increase in the activity of polyphosphate-accumulating organisms (PAOs) and denitrifying polyphosphate-accumulating organisms (DPAOs). The specific phosphate accumulation at the end of the experimental run amounted to 8.0 mg P g − 1 VSS h − 1 and 3.29 mg P g − 1 VSS h − 1 , for the PAOs and DPAOs respectively. Moreover, the DPAOs activity increased faster than PAOs activity, i.e. from 0.36 to 0.41 of phosphate uptake rate (PUR) ratio.

Control of phosphate uptake by zooxanthellae and host cells in the scleractinian coral Stylophora pistillata

Depletion experiments were used to assess the uptake rates of phosphate by the tropical coral Stylophora pistillata and its symbiotic zooxanthellae under different conditions. Our results showed the presence of active phosphate carriers both in the animal and the algal fractions, since uptake kinetics followed uniphasic saturation curves in both compartments (Michaelis‐Menten shape). Transporters in the animal and the algae presented different affinities for phosphate, with higher half‐saturation constants for the animal compartment than for the isolated zooxanthellae (K = 1.08 ± 0.42 vs. 0.57 ± 0.18 µmol L−1). The velocity of phosphate absorption increased in the light, suggesting a relationship with the photosynthetic activity of the zooxanthellae. A correlation was found between phosphate uptake rates and the organic or inorganic feeding history of the corals; rates were indeed 4.6 times higher in 8‐week starved than in fed corals and depended on the repletion status of phosphorus stocks within the symbionts. We report evidence showing that zooxanthellae act as a sink of phosphate within the symbiosis.

Phosphorus input by upwelling in the eastern Gotland Basin (Baltic Sea) in summer and its effects on filamentous cyanobacteria

In July 2007, phosphorus input by an upwelling event along the east coast of Gotland Island and the response of filamentous cyanobacteria were studied to determine whether introduced phosphorus can intensify cyanobacterial bloom formation in the eastern Gotland Basin. Surface temperature, nutrient concentrations, phytoplankton biomass and its stoichiometry, as well as phosphate uptake rates were determined in two transects between the coasts of Gotland and Latvia and in a short grid offshore of Gotland. In the upwelling area, surface temperatures of 11–12 °C and average dissolved inorganic phosphorus (DIP) concentrations of 0.26 μM were measured. Outside the upwelling, surface temperatures were higher (15.5–16.6 °C) and DIP supplies in the upper 10 m layer were exhausted. Nitrite and nitrate concentrations (0.01–0.22 μM) were very low within and outside the upwelling region. Abundances of filamentous cyanobacteria were highly reduced in the upwelling area, accounting for only 1.4–6.0% of the total phytoplankton biomass, in contrast to 18–20% outside the upwelling. The C:P ratio of filamentous cyanobacteria varied between 32.8 and 310 in the upwelling region, most likely due to the introduction of phosphorus-depleted organisms into the upwelling water. These organisms accumulate DIP in upwelling water and have lower C:P ratios as long as they remain in DIP-rich water. Thus, diazotrophic cyanobacteria benefit from phosphorus input directly in the upwelling region. Outside the upwelling region, the C:P ratios of filamentous cyanobacteria varied widely, between 240 and 463, whereas those of particulate material in the water ranged only between 96 and 224. To reduce their C:P ratio from 300 to 35, cyanobacteria in the upwelling region had to take up 0.05 mmol m −3 DIP, which is about 20% of the available DIP. Thus, a larger biomass of filamentous cyanobacteria may be able to benefit from a given DIP input. As determined from the DIP uptake rates measured in upwelling cells, the time needed to reduce the C:P ratio from 300 to 35 was too long to explain the huge bloom formations that typically occur in summer. However, phosphorus uptake rates increased significantly with increasing C:P ratios, allowing phosphorus accumulation within 4–5 days, a span of time suitable for bloom formation in July and August.

Novel NaPi-2c mutations that cause mistargeting of NaPi-2c protein and uncoupling of Na-Picotransport cause HHRH

hereditary hypophosphatemic rickets with hypercalciuria (HHRH) is an autosomal recessive inherited disorder of mineral and bone metabolism. It is characterized by hypophosphatemia, rickets, and increased serum 1,25-dihydroxyvitamin D concentration, resulting in secondary absortive hypercalciuria and

Changes in nutrient uptake of phytoplankton under the interaction between sunlight and phosphate in the Changjiang (Yangtze) River Estuary

We conducted ship-board incubation experiments to investigate changes in nutrient uptake of phytoplankton under different phosphate concentrations and irradiances in the Changjiang River Estuary and its adjacent waters in China. Under 100% natural irradiance the uptake rates of phosphate, silicate, and nitrate were accelerated at high phosphate levels (1.84 μM), while under low irradiance (about 50% natural irradiance) their uptake rates were restrained at the high but stimulated greatly at the intermediate phosphate concentrations (1.26 μM), as the growth of phytoplankton, changes in nitrite and ammonium uptake didn’t follow an obvious pattern. Our results also showed that there were linear relationships between nitrate, silicate and phosphate uptake at different phosphate concentrations under low and high irradiances, and the growth period of phytoplankton was prolonged both at the high phosphate concentrations under high irradiance and at the intermediate concentrations under low irradiance, suggesting that the limitation of phytoplankton growth mainly reflected changes in its growth period, and because no such environment (low irradiance and low phosphate concentrations) actually existed in a high turbidity zone, phytoplankton blooms hardly occurred there. In the absence of irradiance, denitrification occurred readily and phytoplankton was kept decreasing, which resulted in phosphate regeneration.

Luminal fructose inhibits rat intestinal sodium-phosphate cotransporter gene expression and phosphate uptake

BackgroundWhile searching by microarray for sugar-responsive genes, we inadvertently discovered that sodium-phosphate cotransporter 2B (NaPi-2b) mRNA concentrations were much lower in fructose-perfused than in glucose-perfused intestines of neonatal rats. Changes in NaPi-2b mRNA abundance by sugars were accompanied by similar changes in NaPi-2b protein abundance and in rates of inorganic phosphate (Pi) uptake. ObjectiveWe tested the hypothesis that luminal fructose regulates NaPi-2b. DesignWe perfused into the intestine fructose, glucose, and nonmetabolizable or poorly transported glucose analogs as well as phlorizin. ResultsNaPi-2b mRNA concentrations and Pi uptake rates in fructose-perfused intestines were ≈30% of those in glucose and its analogs. NaPi-2b inhibition by fructose is specific because the mRNA abundance and activity of the fructose transporter GLUT5 (glucose transporter 5) increased with fructose perfusion, whereas those of other transporters were independent of the perfusate. Plasma Pi after 4 h of perfusion was independent of the perfusate, probably because normal kidneys can maintain normophosphatemia. Inhibiting glucose-6-phosphatase, another fructose-responsive gene, with tungstate or vanadate nonspecifically inhibited NaPi-2b mRNA expression and Pi uptake in both glucose- or fructose-perfused intestines. The AMP kinase (AMPK)–activator AICAR (5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside) enhanced and the fatty acid synthase–AMPK inhibitor C75 (3-carboxy-4-octyl-2-methylenebutyrolactone trans-4-carboxy-5-octyl-3-methylenebutyrolactone) prevented fructose inhibition of NaPi-2b but had no effect on expression of other transporters. NaPi-2b expression decreased markedly with age and was inhibited by fructose in all age groups. ConclusionsEnergy levels in enterocytes may play a role in NaPi-2b inhibition by luminal fructose. Consumption of fructose that supplies ≈10% of caloric intake by Americans clearly affects absorption of Pi and may promote Pi homeostasis in patients with impaired renal function.

25: Functional Analysis of Human Mutations in NAPI-IIC Reveals Important Residues for Surface Expression and Sodium-Phosphate Co-Transport

FUNCTIONAL ANALYSIS OF HUMAN MUTATIONS IN NAPIIIC REVEALS IMPORTANT RESIDUES FOR SURFACE EXPRESSION AND SODIUM-PHOSPHATE CO-TRANSPORT Clemens Bergwitz1 Graciana Jaureguiberry1, Thomas O Carpenter3, Stuart Forman2, Harald Juppner1 1Endocrine Unit and 2Dept. of Anesthesiology, Massachusetts General Hospital, Boston, MA, United States; 3 Dept. of Pediatrics and Endocrine Unit, Yale School of Medicine, New Haven, CT, United States. We recently reported homozygous and compound heterozygous lossof-function mutations in SLC34A3/NaPi-IIc as the cause for hereditary hypophosphatemic rickets with hypercalciuria (HHRH). To better understand how some of the point mutations reported by us and others (T137M, S138F, S192L, G196R, R468W, del527L, R353L, D237N and A413E) lead to renal phosphate wasting, we generated expression plasmids encoding enhanced green-fluorescence protein (EGFP) concatenated to the N-terminus of wild-type or mutant human NaPi-IIc. After transient transfection in Opossum kidney cells G196R and R468W were not expressed in apical patches (the renal brush border membrane equivalent), nor were these mutants present in plasma membranes of Xenopus oocytes following cRNA injection (50 ng/oocyte). For S138F, S192L, R353L, D237N and A413E oocyte membrane fluorescence was reduced to <20% compared to EGFP-hNaPi-IIc, as quantified by confocal microscopy. The T137M and delL527L mutants were expressed in both kidney cells and oocytes, and sodium-dependent [33P]-uptake into oocytes corrected for surface expression was preserved. When further investigated, the Na:P-stoichiometry of simultaneous [P]and [Na]-uptake was increased from 2.3±0.4 in wild-type to 7.1±3.6 and 23±13 for T137M and delL527L, respectively. Furthermore, two-electrode studies indicated that EGFP-hNaPi-IIc carrying these mutations remains non-electrogenic, like wild-type NaPi-IIc, but displayed a significant phosphate-independent inward-rectified sodiumleak current which appears to be insensitive to phosphonoformic acid (PFA), a known inhibitor of sodium-dependent phosphate co-transport. T137M and delL527L may thus reduce the rate of phosphate uptake by uncoupling sodium-phosphate co-transport, suggesting that these amino acid residues have an important functional role in human NaPi-IIc.

Differential effects of nutrients and light on the primary production of stream algae and mosses

Benthic algae and mosses are the main primary producers in headwater streams. In these ecosystems, primary production is mainly determined by the availability of light and nutrients. The present study analyses the different effects of nutrient enrichment (inorganic phosphorus and nitrogen) and light availability on the primary production of both algal and moss communities from a headwater forested stream using laboratory experiments. These laboratory experiments consider four treatments (low light-unenriched, high light-unenriched, low light-enriched and high light-enriched). Photosynthesis-irradiance curves of both communities were also performed. Respiration and net primary production (NPP) of algae and mosses were measured using incubation chambers and oxygen balance measurements. The moss community was dominated by Fontinalis antipyretica and diatom epiphytes, while the algal community consisted of Cladophora glomerata and attached diatoms. Under all treatments, NPP was significantly higher for algae (3-18 mg O 2 mg chl -1 h -1 ) than for mosses (0.4 and 1.8 mg O 2 mg chl -1 h -1 ). Light (as a single factor) significantly affected GPP (gross primary production) and NPP of algae and mosses. Non-inhibitory effects of GPP were observed at saturating light conditions, showing the high plasticity of the stream algal and moss communities. Nutrients produced a significant enhancement of NPP only under high light availability. The greater response of algae to nutrient enrichment was also shown by the highest phosphate uptake rate of this community. Extrapolation of laboratory primary production measurements to the field scale showed the occurrence of significant autotrophic production pulses during periods of light availability (e.g. before leaf emergence and after leaf fall in Mediterranean forested streams), in contrast to the major heterotrophic behaviour, especially in autumn, of these ecosystems. These production pulses in heterotrophic streams could provide high-quality resources to downstream reach, which might be essential for consumers.

English

Phosphorous (P) starved cells of the cyanobacterium&nbsp;Anabaena oryzae&nbsp;showed higher phosphate uptake rates than P-sufficient cells. The P-uptake obeyed saturation kinetics. The Km value for P-deficient cells was lower (54.34&nbsp;mM) than P-sufficient cells (82.64mM) while Vmax&nbsp;was higher in P-deficient and lower in P-sufficient cells. Salinity (NaCl) stimulated phosphate uptake significantly in the cyanobacterium which is followed by greater amount of P-accumulation in the form of polyphosphate bodies. Inhibition of P-uptake in P-deficient cells was 45% in dark grown compared to light grown cells. P-uptake was inhibited 52 and 85% in culture treated with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU; 10&nbsp;mM) and carbonyl cyanide m-chloro phenylhydrazone (CCCP; 100&nbsp;mM), respectively, suggesting that energy for uptake could be derived from oxidative phosphorylation and photophosphorelation. &nbsp; Key words:&nbsp;Anabaena oryzae, metabolic inhibitors, phosphorus-uptake, salinity.

Influence of ammonium, nitrate and nitrite on the performance of the pure culture of Acinetobacter junii

The influence of different concentration ranges (0-500 mg/L) of ammonium, nitrate and nitrite presence in the wastewater, on the performance of the pure culture of phosphate-accumulating bacterium Acinetobacter junii in the anaerobic and aerobic conditions, was investigated. A. junii was able to use ammonium and nitrate salts as the source of nitrogen, unlike in the case of nitrite salt. Comparing to the control reactors with the peptone and yeast extract as the sources of nitrogen, at the lowest tested concentration of ammonium and nitrate the performance of the system was inhibited due to the nitrogen deficit in the wastewater, while at the highest concentration it was positively influenced. Nitrite in all concentrations detrimentally affected the phosphate release and uptake rates, chemical oxygen demand uptake rates, nitrogen uptake rates, as well as multiplication of A. junii. The higher the nitrite concentration, the more pronounced was the effect. At the highest nitrite concentration tested a complete failure of the system was observed.

Adsorptive Removal of Phosphate Ions from Aqueous Solution Using Synthetic Zeolite

Phosphate ions are responsible for the algal bloom in receiving water bodies and aesthetic problems in drinking water. From the environmental and economic points of view, management of such a contaminant and valuable resource is very important. The present paper deals with the removal of inorganic phosphate ions from aqueous solutions using synthetic HSZ 330 HUD Zeolite (Si/Al ratio: 2.75−3.25) and its Al3+-activated form (Al-HUD) as adsorbents. Equilibrium and kinetic experiments were performed to study the effects of operating conditions such as adsorbent mass, solution pH, coexisting ions, and initial concentration on either the capacity or the rate of phosphate uptake by the zeolites. As a result, it was found that the efficiency of phosphate removal by the zeolites increased with an increase in adsorbent mass and a decrease in solution pH. Outer-sphere complex-forming ions such as nitrate, sulfate, and chloride improved slightly the phosphate removal efficiency while fluoride ions, which form inner-...