Polyphosphate kinase genes from activated sludge carrying out enhanced biological phosphorus removal

2002 ◽  
Vol 46 (1-2) ◽  
pp. 155-162 ◽  
Author(s):  
K.D. McMahon ◽  
D. Jenkins ◽  
J.D. Keasling
Keyword(s):  
Community Structure ◽  
Activated Sludge ◽  
Phosphorus Removal ◽  
Small Subunit ◽  
Close Relative ◽  
Polyphosphate Kinase ◽  
Batch Reactors ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Biological Phosphorus

The community structure and metabolic function of activated sludge carrying out enhanced biological phosphorus removal have been investigated. Laboratory-scale sequencing batch reactors were operated at several influent COD/P ratios to obtain sludges with a range of phosphorus contents. Molecular microbiological techniques based on small subunit ribosomal RNA were used to characterize the community structure of these sludges. The dominant polyphosphate accumulating organism was a close relative of Rhodocyclus tenuis, a member of the β subclass of the Proteobacteria. Fragments of genes coding for polyphosphate kinase (PPK), thought to be responsible for polyphosphate accumulation, were retrieved from one of the sludges. The relative abundance of PPK gene copies in genomic DNA extracted from sludges was determined to confirm that at least one of the PPK gene sequences was derived from the dominant polyphosphate accumulating organism.

scholarly journals Polyphosphate Kinase from Activated Sludge Performing Enhanced Biological Phosphorus Removal

2002 ◽  
Vol 68 (10) ◽  
pp. 4971-4978 ◽  
Author(s):  
Katherine D. McMahon ◽  
Michael A. Dojka ◽  
Norman R. Pace ◽  
David Jenkins ◽  
Jay D. Keasling
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Specific Activity ◽  
Inverse Pcr ◽  
Rrna Genes ◽  
Polyphosphate Kinase ◽  
Type I ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Biological Phosphorus

ABSTRACT A novel polyphosphate kinase (PPK) was retrieved from an uncultivated organism in activated sludge carrying out enhanced biological phosphorus removal (EBPR). Acetate-fed laboratory-scale sequencing batch reactors were used to maintain sludge with a high phosphorus content (approximately 11% of the biomass). PCR-based clone libraries of small subunit rRNA genes and fluorescent in situ hybridization (FISH) were used to verify that the sludge was enriched in Rhodocyclus-like β-Proteobacteria known to be associated with sludges carrying out EBPR. These organisms comprised approximately 80% of total bacteria in the sludge, as assessed by FISH. Degenerate PCR primers were designed to retrieve fragments of putative ppk genes from a pure culture of Rhodocyclus tenuis and from organisms in the sludge. Four novel ppk homologs were found in the sludge, and two of these (types I and II) shared a high degree of amino acid similarity with R. tenuis PPK (86 and 87% similarity, respectively). Dot blot analysis of total RNA extracted from sludge demonstrated that the Type I ppk mRNA was present, indicating that this gene is expressed during EBPR. Inverse PCR was used to obtain the full Type I sequence from sludge DNA, and a full-length PPK was cloned, overexpressed, and purified to near homogeneity. The purified PPK has a specific activity comparable to that of other PPKs, has a requirement for Mg2+, and does not appear to operate in reverse. PPK activity was found mainly in the particulate fraction of lysed sludge microorganisms.

Biochemical Aspects of Enhanced Biological Phosphorus Removal from Wastewater

1985 ◽  
Vol 17 (11-12) ◽  
pp. 23-41 ◽  
Author(s):  
M. C. Hascoet ◽  
M. Florentz ◽  
P. Granger
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Phosphorus Uptake ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
The Past ◽  
Nitrate Addition ◽  
The Subject ◽  
Biological Phosphorus ◽  
Microbiological Analyses

Enhanced biological phosphorus removal from wastewater by means of microorganisms found in activated sludge has for the past few years been the subject of much research and it is now commonly recognized that an activated sludge system must include alternating anaerobic-aerobic periods. The present article covers biochemical aspects of this phenomenon using a phosphorus removing biomass obtained in a laboratory-scale pilot with alternating phases and a synthetic substrate feed. The percentage of phosphorus obtained in the pilot sludge was four times greater than that of a conventional sludge plant. By exposing the same biomass to different conditions and using 31P Nuclear Magnetic Resonance, we were able to accurately pin-point the various forms of phosphorus found within cells and follow their development during the course of alternating phases. The following results were obtained:the transformation of phosphorus in its inorganic to polyphosphate form depends on the medium's level of oxygenation,the presence of nitrates disturbs the anaerobic period but does not affect phosphorus uptake in the aerated period.Continuous nitrate addition alters biomass behaviour in the anaerobic phase, which loses the capacity to release phosphorus,copper at a concentration of over 1 mg Cu2+/1 inhibits phosphorus uptake in the aerated phase. Various microbiological analyses made on the pilot biomass isolated conventional bacteria found in activated sludge.

An enhanced biological phosphorus removal (EBPR) control strategy for sequencing batch reactors (SBRs)

2001 ◽  
Vol 43 (3) ◽  
pp. 183-189 ◽  
Author(s):  
C. Y. Dassanayake ◽  
R. L. Irvine
Keyword(s):  
Control Strategy ◽  
Phosphorus Removal ◽  
Batch Reactor ◽  
Past Research ◽  
P Uptake ◽  
Batch Reactors ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Aeration Time ◽  
Biological Phosphorus

A control strategy was developed for enhanced biological phosphorus removal (EBPR) in a Sequencing Batch Reactor (SBR). Unlike past research that focused on maximizing polyhdroxyalkanoate (PHA) formation during the anaerobic period, this study investigated some of the factors that govern aerobic PHA dynamics and its efficient regulation during phosphate (P) uptake. Influent COD, influent P, and the time for aeration were critical factors that governed PHA use and P uptake during aerated react. Unnecessary PHA oxidation (i.e., in the absence of extracellular P) occurred if the time for aerated react exceeded the time required for P uptake. By adjusting the aeration time to that required for P uptake, residual PHA was sustained in the SBR and excess phosphate uptake reaction potential (PRP) was generated for use during transient influent excursions in P. Unlike space oriented systems, the time for react is simply adjusted in the SBR. Because residual PHA is easily maintained once achieved, high influent COD events can be harnessed to increase or sustain excess PRP for management of expected variations in influent P.

Design of nutrient removal activated sludge systems

2003 ◽  
Vol 47 (11) ◽  
pp. 115-122 ◽  
Author(s):  
J. Manga ◽  
J. Ferrer ◽  
A. Seco ◽  
F. Garcia-Usach
Keyword(s):  
Mathematical Model ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Pilot Plant ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
User Friendly ◽  
Biological Phosphorus ◽  
Activated Sludge Systems

A mechanistic mathematical model for nutrient and organic matter removal was used to describe the behavior of a nitrification denitrification enhanced biological phosphorus removal (NDEBPR) system. This model was implemented in a user-friendly software DESASS (design and simulation of activated sludge systems). A 484-L pilot plant was operated to verify the model results. The pilot plant was operated for three years over three different sludge ages. The validity of the model was confirmed with data from the pilot plant. Also, the utility of DESASS as a valuable tool for designing NDEBPR systems was confirmed.

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