Stoichiometry and kinetics of acetate uptake under anaerobic conditions by an enriched culture of phosphorus-accumulating organisms at different pHs

2001 ◽  
Vol 76 (1) ◽  
pp. 32-43 ◽  
Author(s):  
Carlos D. M. Filipe ◽  
Glen T. Daigger ◽  
C. P. Leslie Grady
Keyword(s):  
Anaerobic Conditions ◽  
Acetate Uptake ◽  
Kinetics Of

New highly efficient coulometric cell with homogenous potential distribution on the working electrode

1986 ◽  
Vol 51 (3) ◽  
pp. 636-642
Author(s):  
Michal Németh ◽  
Ján Mocák
Keyword(s):  
Chemical Reactions ◽  
Potential Distribution ◽  
Anaerobic Conditions ◽  
Highly Efficient ◽  
Working Electrode ◽  
Constant Potential ◽  
Quantitative Analyses ◽  
Mechanism And Kinetics ◽  
Kinetics Of

A highly efficient coulometric cell was designed and constructed, ensuring a constant potential over the whole surface of the working electrode and suitable for very rapid electrolysis. It consists of concentric cylindrical Teflon parts; also the working and auxiliary electrodes are cylindrical and concentric. Electrolysis can be carried out under anaerobic conditions. Functioning of the cell was tested on the oxidation of hexacyanoferrate(II) and chlorpromazine and reduction of hexacyanoferrate(III). The new cell is suitable for routine quantitative analyses and in studying the mechanism and kinetics of moderately rapid chemical reactions.

Metabolic model for acetate uptake by a mixed culture of phosphate- and glycogen-accumulating organisms under anaerobic conditions

2003 ◽  
Vol 84 (3) ◽  
pp. 359-373 ◽  
Author(s):  
Nevin Yagci ◽  
Nazik Artan ◽  
Emine Ubay Çokgör ◽  
Clifford W. Randall ◽  
Derin Orhon
Keyword(s):  
Mixed Culture ◽  
Metabolic Model ◽  
Anaerobic Conditions ◽  
Acetate Uptake

Evaluation of state variable interface between the Activated Sludge Models and Anaerobic Digestion Model no 1

2008 ◽  
Vol 57 (6) ◽  
pp. 901-907 ◽  
Author(s):  
H. Yasui ◽  
K. Komatsu ◽  
R. Goel ◽  
Y. Y. Li ◽  
T. Noike
Keyword(s):  
Activated Sludge ◽  
State Of The Art ◽  
Degradation Kinetics ◽  
The State ◽  
State Variables ◽  
Anaerobic Conditions ◽  
State Variable ◽  
Kinetics Of ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

For plant wide modelling of wastewater treatment, it is necessary to develop a suitable state variables interface for integrating state of the art models of ASM and ADM1. ADM1 currently describes such an interface, however, its suitability needs to be experimentally evaluated. In this study, we characterised activated sludge under aerobic and anaerobic conditions to obtain representative state variables for both models. ASM state variables of XS, XH and XI (as obtained from aerobic tests) and ADM1 state variables of XC and XI (as obtained from anaerobic tests) were then correlated to assess the suitability of current interface. Based on the seven datasets of this study and seven datasets from literatures, it was found that in general ASM state variables were well correlated to the state variables of ADM1. The ADM1 state variable of XC could be correlated to the sum of state variables of XS and XH, while XI in both the models showed direct correspondence. It was also observed that the degradation kinetics of XC under anaerobic condition could be better described by individual degradation kinetics of XS and XH. Therefore, to establish a one to one correspondence between ASM and ADM1 state variables and better description of degradation kinetics in ADM1, replacing the composite variable of XC by the state variables of XS and XH is recommended.

scholarly journals Impact of Soil Aeration on the Environmental Fate of Pre-Emergent Herbicide Metolachlor

2021 ◽  
Vol 11 (18) ◽  
pp. 8567
Author(s):  
Ramdas Kanissery ◽  
Wenwen Liu ◽  
Ruby Tiwari ◽  
Gerald Sims
Keyword(s):  
Weed Management ◽  
Environmental Fate ◽  
Field Application ◽  
Anaerobic Conditions ◽  
Soil Microcosms ◽  
Soil Redox ◽  
Herbicide Metolachlor ◽  
Adsorption Desorption ◽  
The Impact ◽  
Kinetics Of

The impact of the aeration status of soils on the environmental fate of the soil-applied pre-emergent herbicide metolachlor is of significance to sustainable agriculture practices and has not been investigated thoroughly by existing research works. To address this knowledge gap, we examined the adsorption, desorption, degradation, and mineralization of radioactively labeled [14C] metolachlor in Catlin, Flanagan, and Drummer soils under aerobic and anaerobic conditions. Based on our findings, anaerobic conditions in the soil significantly reduced the adsorption of 14C-metolachlor while also promoting its desorption, thereby potentially releasing a greater amount of herbicide from the soil after a field application. The first-order degradation and mineralization kinetics of 14C-metolachlor were distinctively enhanced by anaerobic conditions in all the soils tested. Furthermore, the degradation and mineralization rates of 14C-metolachlor in non-sterilized versus sterilized soil microcosms clearly indicated microbial activity in the degradation of metolachlor in soil. The results from this study suggest that soil redox conditions could impact the bioavailability and environmental fate of herbicide metolachlor and should be taken into consideration as part of sustainable weed management programs.

Reductive nitrosylation of ferric carboxymethylated-cytochrome c

2017 ◽  
Vol 21 (01) ◽  
pp. 1-9 ◽  
Author(s):  
Paolo Ascenzi ◽  
Chiara Ciaccio ◽  
Giovanna De Simone ◽  
Roberto Santucci ◽  
Massimo Coletta
Keyword(s):  
Cytochrome C ◽  
Axial Ligand ◽  
Ligand Concentration ◽  
Anaerobic Conditions ◽  
Reductive Nitrosylation ◽  
Axial Bond ◽  
Kinetics Of ◽  
Mediated Reduction

Horse heart carboxymethylated-cyt[Formula: see text] (CM-cyt[Formula: see text] displays myoglobin-like properties due to the cleavage of the heme-Fe-Met80 axial bond. Here, reductive nitrosylation of CM-cyt[Formula: see text](III) between pH 8.5 and 9.5, at [Formula: see text] 20.0 C, is reported. Under anaerobic conditions, the addition of NO to CM-cyt[Formula: see text](III) leads to the transient formation of CM-cyt[Formula: see text](III)-NO in equilibrium with CM-cyt[Formula: see text](II)-NO[Formula: see text]. In turn, CM-cyt[Formula: see text](II)-NO[Formula: see text] is converted to CM-cyt[Formula: see text](II) by OH[Formula: see text]-based catalysis. Then, CM-cyt[Formula: see text](II) binds NO very rapidly leading to CM-cyt[Formula: see text](II)-NO. Kinetics of NO binding to CM-cyt[Formula: see text](III) is independent of the ligand concentration, [Formula: see text] values ranging between 3.6 ± 0.4 s[Formula: see text] and 7.1 ± 0.7 s[Formula: see text]. This indicates that the formation of the CM-cytc(III)-NO complex is rate-limited by the cleavage of the weak heme-Fe(III) distal bond (likely Lys79). The conversion of CM-cyt[Formula: see text](III)-NO to CM-cyt[Formula: see text](II)-NO is rate-limited by the OH[Formula: see text]-mediated reduction of CM-cyt[Formula: see text](II)-NO[Formula: see text] ([Formula: see text] (1.2 ± 0.1) × 103 M[Formula: see text].s[Formula: see text]. Lastly, the very fast nitrosylation of CM-cyt[Formula: see text](II) takes place, values of [Formula: see text] ranging between[Formula: see text]5.3 × 106 M[Formula: see text].s[Formula: see text] and 1.4 × 107 M[Formula: see text].s[Formula: see text]. These results indicate that CM-cyt[Formula: see text] behaves as the cardiolipin-cyt[Formula: see text] complex highlighting the role of the sixth axial ligand of the heme-Fe atom in the modulation of the metal-based reactivity.

Acetate uptake efficiency of polyphosphate-accumulating organisms under exposure to surfactants

2009 ◽  
Vol 60 (11) ◽  
pp. 2775-2780
Author(s):  
K. Tsuji ◽  
M. Fujita ◽  
H. Furumai
Keyword(s):  
Municipal Wastewater ◽  
Batch Reactor ◽  
Alcohol Ethoxylates ◽  
Anaerobic Conditions ◽  
Linear Alkylbenzene ◽  
Acetate Uptake ◽  
Batch Tests ◽  
Linear Alkylbenzene Sulfonates ◽  
Negative Impacts ◽  
Polyphosphate Accumulating Organisms

We investigated the influence of surfactants such as linear alkylbenzene sulfonates (LAS) and alcohol ethoxylates (AE) on acetate uptake by polyphosphate-accumulating organisms (PAOs) under anaerobic conditions, using the phosphate requirement for acetate uptake (+ΔP/−ΔAc ratio). In order to estimate the +ΔP/−ΔAc ratio, anaerobic batch tests were conducted using activated sludge collected from an anaerobic/oxic sequencing batch reactor used to treat municipal wastewater continuously supplemented with a detergent containing LAS and AE. We demonstrated that LAS and AE have both positive and negative impacts on acetate uptake by PAOs. The disadvantage is that long-term exposure to the detergent inhibits acetate uptake by PAOs, thus deteriorating the efficiency, even if the surfactants are no longer present during the tests. Furthermore, the existence of LAS and/or AE with acetate further diminishes the efficiency. The advantage is that LAS and AE are potential sources of polyhydroxyalkanoate for PAOs, because acetate is produced from the surfactants under anaerobic conditions.

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