Higher Phosphorus Uptake Research Articles

Phosphate uptake performance of bacteria isolated from a full‐scale Izmir municipal wastewater treatment plant

This study investigated the phosphate uptake capacities of bacteria isolated from aerobic and anaerobic phosphate removal tanks at a municipal wastewater treatment plant in Izmir, Turkey, removing chemical oxygen demand to nitrogen (COD‐N) and phosphorus (P) on a full‐scale basis. Conventional plating techniques and an enrichment culture method were used to isolate the colonies, with a total of 91 monoculture isolates from the sludge samples being subjected to phosphate uptake studies. A total of 64 of these isolates had high phosphate uptake capacities ranging from 3.7 × 10−10 to 1.0 × 10−12 mg PO4 3− cell−1, and only 11 of the strains with high phosphate uptake were Gram‐negative. The highest phosphorus uptake value was 3.7 × 10−10 mg PO4 −3 cell−1, which was achieved by Gram‐positive bacteria. Gram‐negative strains were identified as Acinetobacter baumannii with a 99% probability and as Pseudomonas aeruginosa with a 96–98% probability (API 20 NE).

FUNCTIONAL SYNERGISM AMONG GLOMUS FASCICULATUM, TRICHODERMA VIRIDE AND PSEUDOMONAS FLUORESCENS ON FUSARIUM WILT IN TOMATO

The study was carried out to investigate the effectiveness of Glomus fasciculatum, Trichoderma viride and Pseudomonas fluorescens, alone and in combinations to control disease spread in tomato plants infected with Fusarium oxysporum f. sp. lycopersici. The three biological control agents were effective in controlling the disease; however the success rate for inhibition varied among the different treatments. Plants inoculated with P. fluorescens had higher concentration of phenol and greater activities of phenylalanine ammonia lyase and catalase. Inoculation with T. viride led to maximum induction of anti-oxidative enzymes such as catalase and peroxidase. On the other hand, G. fasciculatum-inoculated plants showed improved growth and highest phosphorus uptake. A combination of all the three biocontrol agents together, promoted growth and inhibited disease up to 94% in tomato plants. Thus, use of multiple biocontrol agents leads to enhanced level of disease resistance than individual use of bio-inoculants through the induction of multiple defense mechanisms.

Monitoring of microbial storage products and the effciency of an activated sludge plant performing anoxic phosphorus removal under different operational conditions

The present work focuses on the operation of a continuous flow laboratory scale plant for enhanced biological phosphorus removal (EBPR) from synthetic wastewater. After the acclimatization period, basic operational conditions, namely the influent COD concentration and the anoxic to anaerobic tank volumes ratio, varied, in order to evaluate their impact to the system performance. The progressive increase of the influent COD concentration from 200 mg COD/l to 300 and 400 with constant influent phosphate concentration of 15 mg PO -3 4 -P/l, led to proportional increase of the intracellular PHAs used during the anoxic phosphorus uptake process and to the respective amount of nitrate denitrified. However, the highest phosphorus uptake rate and the maximum net phosphorus removal were observed for the influent COD/P concentrations ratio of 20 (300 mg COD/l). Interestingly, this was also the ratio where the maximum carbohydrates synthesis and biomass P content during the anoxic phase were observed, indicating this, as the optimum ratio for the system efficiency. In a second operational period and for this particular COD/P ratio, three different anaerobic hydraulic residence times (HRT) were imposed, by increasing the volume of the anaerobic tank, in order to achieve anoxic to anaerobic HRT ratios of 2.33, 1.75 and 1.4. The experimental results indicated that decreased ratio values led to increased PHAs utilization for phosphorus removal. Furthermore, despite the considerable increase of the specific P uptake rate, the specific anaerobic P release rate remained almost constant, irrespective to the anoxic to anaerobic HRT ratio. The maximum net phosphorus removal was observed for the minimum ratio, indicating that increased anaerobic contact time enhances the activity of polyphosphate accumulating organisms (PAOs) in the EBPR plant. The biomass growth yield was not influenced by the anoxic to anaerobic HRT ratio and remained constant at 0.27 gVSS/gCOD. Phosphorus removal under alternative anaerobic/anoxic conditions proved its practical feasibility and satisfactory efficiency in a continuous flow activated sludge system.

Rhizosphere effect of different aquatic plants on phosphorus depletion

A series of pot experiments with Alternanthera philoxeroides, Typha latifolia, Sagittaria sagittifolia and Phragmites communis were conducted to assess the phosphorus depletion effect in the rhizosphere. The ratio of root to shoot, root morphology, phosphorus uptake efficiency and phosphorus utilization efficiency were analyzed. An obvious variation in phosphorus concentrations between the rhizosphere soil and non-rhizosphere soil was observed. The water-soluble P contents in the rhizosphere soil of A. philoxeroides, T. latifolia, S. sagittifolia and P. communis were reduced by 81%, 42%, 18% and 16%, respectively, compared with that in the non-rhizosphere soil. A. philoxeroides had the highest phosphorus uptake efficiency (1.32 mg/m), while T. latifolia achieved the effective phosphorus depletion by the strong rooting system and the high phosphorus uptake efficiency (0.52 mg/m). T. latifolia not only used phosphorus to produce biomass economically, but also adjusted carbon allocation to the roots to explore the soil for more available phosphorus. A. philoxeroides and T. latifolia were more effective in depleting phosphorus in the rhizosphere than S. sagittifolia and P. communis.

EDTA-Enhanced Phytoremediation of Lead-Contaminated Soil by Corn

ABSTRACT EDTA-enhanced phytoremediation by corn (Zea mays L.) of soil supplemented with 500 mg L−1 lead (Pb) was examined. The chelate EDTA was used in order to increase Pb bioavailability at four levels: 0 (control), 0.5 (low), 1.0 (medium), and 2.5 mmol kg−1 (high). Plants were grown under controlled conditions in a growth-chamber with supplementary light. An EDTA concentration of 5.0 mmol kg−1 was lethal to plants. At high and medium EDTA levels plants grew significantly less than control ones. Lead concentrations in corn leaves increased with increased EDTA levels. Plants subjected to medium EDTA level had the greatest root to shoot Pb translocation. Plants subjected to high EDTA level showed high phosphorus (P) uptake and translocation within plants. Therefore, possibly it was not only Pb that caused toxic effect on plants, but also the high internal concentration of P that in turn could have complexed active Fe.

Onset and persistence of cyanobacterial blooms in a large impounded tropical river, Australia

The dynamic interplay between physical, chemical and biological factors in the development and persistence of cyanobacterial blooms in impounded rivers is an important topic. Over a 3-year study period, variable climatic conditions were recorded in the Fitzroy River, Queensland, Australia, which is a typical, impounded lowland tropical river. Post-flood turbidity reduced the available light in the well-mixed water column to levels insufficient for cyanobacterial growth. Only when the water column stratified and the slowly sinking particles dropped from the surface layer did the ratio of surface mixed layer depth to euphotic depth approach 1, allowing cyanobacterial growth. By the time the light climate became favorable, most of the dissolved nutrients had been scavenged from the water column by settling particles or sequestered by fringing macrophytes and other biogeochemical processes. Cyanobacterial blooms dominated by Cylindrospermopsis raciborskii persisted for several months until the next flood flushed the system. The cyanobacterial species dominating that environment were very small and had high specific phosphorus uptake rates. Their nutrient requirement was met by transfer across the oxycline driven by regular high wind mixing events, entraining nutrient-rich bottom waters. Nutrient fluxes from the sediments into the anoxic bottom layer were sufficient to replace the bottom nutrients lost to the surface layer.

Influence of the nutrient balance on biofilm composition in a fixed film process

An attached fungal growth has appeared in a fixed biofilm process at the waste water treatment plant of the City of Oulu, Finland. Due to the filamentous morphology of the fungi, biofilm support material is easily washed out. The appearance is believed to be the result of the unbalanced availability of nutrients, where phosphorus has been identified as the key component. Experimental work concentrated on the influence of phosphorus on the fungal growth. Bench scale experiments showed that a higher uptake of phosphorus for the removal of organic material is possible, which also resulted in a suppression of the fungal growth by bacterial biomass. The results were confirmed by experimentation in a full-scale biofilter. Addition of extra phosphoric acid to the biofilter influent resulted in a biofilm where the fungal growth is less pronounced. The fungal growth is believed to be competitive with the desired bacterial growth. It is possible to keep the fungal growth within limits by changing the conditions in favour of the bacterial growth, thus avoiding the operational problems connected with the filamentous fungi.

Effects of primary tillage and soil amendment practices on pearl millet yield and nutrient uptake in the Sahel of West Africa

The main objective of this study was to determine the best soil amendment and tillage practices for sustainable millet yield and grain and stover quality. The treatments included tillage practices (immediate-, late- and no-till) and soil amendments (sheep manure plus urine, manure, millet stover (stalks, leaf blades and leaf sheaths) and millet stover ash) in factorial combinations with fertilizer nitrogen levels of 0, 15 and 30 kg ha−1 plus controls. Results showed that (i) higher yields were obtained in tilled plots than in no-till plots; (ii) tillage timing may not be a significant yield determining factor; (iii) the application of animal urine resulted in significantly higher yield and greater nitrogen, phosphorus and potassium uptake than the application either of manure alone or of millet stover. Urine application (ruminant urine contains virtually no phosphorus), which elevates soil pH especially during the first week after application, may have resulted in the dissolution of phosphorus from the aluminium–iron complexes of kaolinitic clays. This is corroborated by the significantly higher phosphorus uptake from the manure-plus-urine plots than from plots amended with either manure alone or millet stover. Long-term implications of ‘mining’ soil phosphorus with repeated applications of animal urine in these fragile ecosystems remains unclear.

Glucose metabolism and kinetics of phosphorus removal by the fermentative bacterium Microlunatus phosphovorus.

Phosphorus and carbon metabolism in Microlunatus phosphovorus was investigated by using a batch reactor to study the kinetics of uptake and release of extracellular compounds, in combination with (31)P and (13)C nuclear magnetic resonance (NMR) to characterize intracellular pools and to trace the fate of carbon substrates through the anaerobic and aerobic cycles. The organism was subjected to repetitive anaerobic and aerobic cycles to induce phosphorus release and uptake in a sequential batch reactor; an ultrafiltration membrane module was required since cell suspensions did not sediment. M. phosphovorus fermented glucose to acetate via an Embden-Meyerhof pathway but was unable to grow under anaerobic conditions. A remarkable time shift was observed between the uptake of glucose and excretion of acetate, resulting in an intracellular accumulation of acetate. The acetate produced was oxidized in the subsequent aerobic stage. Very high phosphorus release and uptake rates were measured, 3.34 mmol g of cell(-1) h(-1) and 1.56 mmol g of cell(-1) h(-1), respectively, values only comparable with those determined in activated sludge. In the aerobic period, growth was strictly dependent on the availability of external phosphate. Natural abundance (13)C NMR showed the presence of reserves of glutamate and trehalose in cell suspensions. Unexpectedly, [1-(13)C]glucose was not significantly channeled to the synthesis of internal reserves in the anaerobic phase, and acetate was not during the aerobic stage, although the glutamate pool became labeled via the exchange with intermediates of the tricarboxylic acid cycle at the level of glutamate dehydrogenase. The intracellular pool of glutamate increased under anaerobic conditions and decreased during the aerobic period. The contribution of M. phosphovorus for phosphorus removal in wastewater treatment plants is discussed on the basis of the metabolic features disclosed by this study.

Evaluation of phosphorus removal in anaerobic-anoxic-aerobic system - via polyhydroxyalkonoates measurements

Accumulating and utilizing PHAs (polyhydroxyalkanoates), i.e. a major carbon reserve of polyphosphate accumulating organisms (PAOs), is a prerequisite for phosphorus removal in an enhanced biological phosphorus removal (EBPR) system. To evaluate phosphorus removal, this study investigates the behavior of PHAs in a hybrid anaerobic-anoxic-aerobic process, operating under various sludge retention times (5, 10, 12 and 15 days) and dissolved oxygen conditions (0.5, 1.0 and 2.0 mg/l in aerobic stage). PHAs and phosphorus measurements in the pilot-scale experiments demonstrate that the PHAs content of sludge closely relates to phosphorus release and uptake behavios under anaerobic and aerobic conditions, respectively. The aerobic specific-phosphorus-uptake-rate is directly proportional to PHAs content of sludge in the anoxic stage. When the process is under a high organic loading condition, the sludge exhibits a large amount of PHAs having accumulated in the anoxic stage and a high phosphorus uptake rate in the subsequent aerobic stage. However, experimental results confirm that anoxic phosphorus release, leading to a high concentration of phosphorus flow into the aerobic stage, causes deficient phosphorus removal under a high organic loading condition. Moreover, a low PHAs content of sludge causes incomplete phosphorus removal; the phenomenon occurs when the process is under a low organic loading condition. Based on the results presented herein, we can conclude that the organic loading should be carefully controlled for phosphorus removal in the anaerobic-anoxic-aerobic process.

INFLUENCE OF RICE BASED CROPPING SYSTEMS ON SOIL HEALTH IN CAUVERY DELTA ZONE OF TAMIL NADU

Field experiments were conducted in low lands at Tamil Nadu Rice Research Institute, Aduthurai, Tamil Nadu for two years (1985-87) to study the change in soil nutrient status due to the rice based cropping systems in Cauvery delta zone. The inclusion of legume in the cropping systems resulted in higher soil nitrogen (+95.2 kg ha¹) and higher phosphorus uptake (13.4 per cent increase). As that of legume, cotton in the systems too resulted in higher soil available nitrogen ( +117.1 kg ha) which might be because of lesser uptake by cotton crop or higher addition of residues by cotton or both. The systems rice-rice-cotton andrice-cotton-cotton second flush possessing cotton as components crop found to leave more phosphorus into the soil because of mining/pumping of phosphorus from deeper soil zone with its deep root system. The systems involving pulses left higher potassium in the soil because of comparatively lesser uptake of potassium by these component crops.

Evaluation of phosphorus removal in anaerobic-anoxic-aerobic system — Via polyhydroxyalkonoates measurements

Accumulating and utilizing PHAs (polyhydroxyalkanoates), i.e. a major carbon reserve of polyphosphate accumulating organisms (PAOs), is a prerequisite for phosphorus removal in an enhanced biological phosphorus removal (EBPR) system. To evaluate phosphorus removal, this study investigates the behavior of PHAs in a hybrid anaerobic-anoxic-aerobic process, operating under various sludge retention times (5, 10, 12 and 15 days) and dissolved oxygen conditions (0.5, 1.0 and 2.0 mg/l in aerobic stage). PHAs and phosphorus measurements in the pilot-scale experiments demonstrate that the PHAs content of sludge closely relates to phosphorus release and uptake behavios under anaerobic and aerobic conditions, respectively. The aerobic specific-phosphorus-uptake-rate is directly proportional to PHAs content of sludge in the anoxic stage. When the process is under a high organic loading condition, the sludge exhibits a large amount of PHAs having accumulated in the anoxic stage and a high phosphorus uptake rate in the subsequent aerobic stage. However, experimental results confirm that anoxic phosphorus release, leading to a high concentration of phosphorus flow into the aerobic stage, causes deficient phosphorus removal under a high organic loading condition. Moreover, a low PHAs content of sludge causes incomplete phosphorus removal; the phenomenon occurs when the process is under a low organic loading condition. Based on the results presented herein, we can conclude that the organic loading should be carefully controlled for phosphorus removal in the anaerobic-anoxic-aerobic process.

INFLUENCE OF RICE BASED CROPPING SYSTEMS ON SOIL HEALTH IN CAUVERY DELTA ZONE OF TAMIL NADU

Field experiments were conducted in low lands at Tamil Nadu Rice Research Institute, Aduthurai, Tamil Nadu for two years (1985-87) to study the change in soil nutrient status due to the rice based cropping systems in Cauvery delta zone. The inclusion of legume in the cropping systems resulted in higher soil nitrogen (+95.2 kg ha) and higher phosphorus uptake (13.4 per cent increase). As that of legume, cotton in the systems too resulted in higher soil available nitrogen ( +117.1 kg ha¹) which might be because of lesser uptake by cotton crop or higher addition of residues by cotton or both. The systems rice-rice-cotton andrice-cotton-cotton second flush possessing cotton as components crop found to leave more phosphorus into the soil because of mining/pumping of phosphorus from deeper soil zone with its deep root system. The systems involving pulses left higher potassium in the soil because of comparatively lesser uptake of potassium by these component crops.

RESIDUAL EFFECTS OF PHOSPHORUS FERTILIZER. II. FOR WHEAT AND FLAX GROWN ON CHERNOZEMIC SOILS IN MANITOBA

Broadcast applications of 0, 100, 200 and 400 kg P/ha were made on two Chernozemic soils in 1965. The soils were cropped for 8 yr in a continuous wheat-flax rotation. In each year, crops grown on the phosphorus treatments yielded more and had higher phosphorus content than crops grown without added phosphorus. Over 8 yr of cropping, 100 kg P/ha was the most efficient treatment in increasing yield. Yield increases beyond 100 kg P/ha were either not significant or only marginally significant. Wheat used twice as much phosphorus as did flax. Together the two crops used approximately 30, 22 and 14% of the 100, 200 and 400 kg P/ha applied. The NaHCO3-extractable phosphorus level of the 100 kg P/ha treatment after 8 yr of cropping was reduced to about 8 kg P/ha which is considered to be inadequate for crop production. Soils treated with 200 and 400 kg P/ha contained high levels of NaHCO3-extractable P (20–54 kg P/ha) and little response in yield to additional P would be expected in the near future. Annual variation in yield and phosphorus uptake by the crops were affected by water supply. In years of high water supply, yield and phosphorus uptake were generally higher than in years of low water supply.

The phosphorus nutrition of the apple tree. II.* Effects of localized phosphate placement on the growth and phosphorus content of split-root trees

Effects of localized placement of superphosphate on the growth and phosphorus content of young apple trees were studied in two successive pot experiments with split-root trees grown in soil. Over a 2-year period both nil and excess superphosphate depressed tree growth, but localized applications of low to moderate rates of superphosphate only slightly depressed total tree growth, compared with uniform application of fertilizer to root parts. This suggests that non-fed root parts are supplied with sufficient phosphorus through redistribution within the tree to maintain active root growth. Tissue analysis clearly showed that the phosphorus content of tree tops in both experiments was dependent upon the proportion of root fertilized as well as the rate of fertilizer applied. However, the uptake of phosphorus by a root part was largely independent of whether superphosphate was applied to the other root parts. Further, a1 low (50–100 g per pot) but not high rates (200 g per pot or higher) of superphosphate, a higher phosphorus uptake per tree resulted from a uniform application of superphosphate than from an equivalent localized application. Although the trees absorbed phosphorus from localized application in proportion to the rate applied, analyses showed that a non-uniform distribution of phosphorus persisted within the trees even after two growing seasons. In particular, the concentration of phosphorus in non-fed roots remained low irrespective of the concentration in the roots in the fertilized zone. Therefore, while apple trees may be able to take up phosphorus from localized placement in proportion to the rate of superphosphate applied, the distribution of that phosphorus in trees following uptake may be non-uniform. The significance of this for tree performance in the field needs assessment in the long term. ____________________ *Part I, Aust. J. Agric. Res., 26: 843 (1975).

Suppression of superphosphate-phosphorus fixation by farmyard manure I. High phosphorus uptake from superphosphate

Abstract Pot and field experiments were conducted on alkaline calcareous soils of Pakistan to determine the effect of premixing superphosphate (SUP) with farmyard manure (FYM) on the fraction of plant phosphorus derived from the 30P labelled SUP (y value). Premixing (SUP with FYM) before their addition to soil, markedly increased the uptake of SUP-P by plants. The premixed treatment also increased crop yield on phosphorus deficient soli. Optimum quantity of FYM required was twice that of SUP. Higher quantities of FYM had no additional effect on phosphorus availability from SUP. The possible mechanism of this effect and the implications of these observations in phosphorus nutrition of plants have been discussed.

Residual effect of rock phosphate and superphosphate

Results are reported of the residual effect of North African finely ground rock phosphate and superphosphate in two field trials on acid fine sand and humus soils. During the first seven years of these trials 166 kg P/ha was applied either as rock phosphate or as superphosphate to cereals and mixed leys. Then crops were grown for three years without any application of phosphorus fertilizers. The phosphorus analyses of the soil at the end of the seventh experimental year proved that the largest part of rock phosphate occurred in the acid soluble fraction, probably mainly as unweathered apatite. The superphosphate phosphorus seemed to be accumulated as fluoride-soluble and alkali-soluble forms. In the trial on the humus soil of a fairly high productivity, the residual effect of both fertilizers on three oat crops was insignificant. In the trial on the poorer fine sand soil, the residues of both fertilizers produced significant and mutually equal increases in the dry matter yields of the oat crop in the first year and of the hay crops in the second and third years. The tendency to a higher phosphorus content in the graminaceous plants from the superphosphate plots resulted in a higher uptake of phosphorus from these plots as compared with the phosphorus yield from the rock phosphate plots; only in the third year the difference was no more significant. Attention was paid to the good capacity of red clover to use phosphorus of rock phosphate.