A kinetic model for energy spilling-associated product formation in substrate-sufficient continuous culture

Liu, Yu; Tay, Joo‐Hwa

doi:10.1046/j.1365-2672.2000.01009.x

Cited by 9 publications

(3 citation statements)

References 15 publications

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“…Therefore, it is necessary to develop a new biological concept to minimize excess sludge production. Significant sludge yield reduction was observed in organic protonphore‐containing cultures (Cook and Russell 1994; Low and Chase 1999; Liu 2000a; Chen et al. 2002a).…”

Section: Introductionmentioning

confidence: 99%

Reduction in excess sludge production by addition of chemical uncouplers in activated sludge batch cultures

Ye¹,

Shen²,

Li³

2003

J Appl Microbiol

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Aims: To investigate the possibility of reducing excess sludge production in activated sludge processes by the addition of chemical uncouplers to greatly dissociate anabolism from catabolism. Methods and Results: Ortho-chlorophenol (oCP), 2,4-dichlorophenol (DCP), 3,3¢,4¢,5-tetrachlorosalicylanilide (TCS), para-dinitrophenol (pNP) and 2,4-dinitrophenol (DNP) were chosen for short-term tests for their ability to reduce sludge yield by shaking bottle test. The most effective chemicals, DNP and pNP, together with TCS were tested for various uncoupler concentrations and biomass concentrations. TCS was tested in a lab-scale completely mixed activated sludge batch culture. The model (demonstrated by Liu) was verified with experimental data in completely mixed activated sludge batch test, but was inconsistent with the results from the shaking bottle batch test. The observed growth yield (Y obs ) decreased with increasing of the ratio of initial uncoupler concentration to initial biomass concentration (C u /X 0 ). Conclusions: We suggest that the uncouplers oCP, DCP, TCS, pNP and DNP can cause a significant decrease in sludge production, the metabolism of which can explain the decline in sludge yield. Significance and Impact of the Study: The real strength of chemical uncoupler imposing on biomass should be C u /X 0 , not initial uncoupler concentration (C u ) alone. Chemical uncouplers can be used to develop the activated sludge processes for minimizing excess sludge production.

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Section: Introductionmentioning

confidence: 99%

Reduction in excess sludge production by addition of chemical uncouplers in activated sludge batch cultures

Ye¹,

Shen²,

Li³

2003

J Appl Microbiol

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“…Any microbial process is difficult to employ in the real world unless it is accompanied by a quantitative process model. Existing models for metabolic uncoupling describe either (1) the effect of excess-substrate [Liu, 1996], or (2) the effect of a chemical uncoupler [Liu and Tay, 2000a]. However, no model is currently available to explain the behavior of microbes under the influence of both the excess-substrate and the presence of a chemical uncoupler.…”

Section: Metabolic Uncouplingmentioning

confidence: 99%

Influence of Reactive Transport on the Reduction of U(VI) in the Presence of Fe(III) and Nitrate: Implications for U(VI) Immobilization by Bioremediation / Biobarriers- Final Report

Wood¹

2007

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Subsurface contamination by metals and radionuclides represent some of the most challenging remediation problems confronting the Department of Energy (DOE) complex. In situ remediation of these contaminants by dissimilatory metal reducing bacteria (DMRB) has been proposed as a potential cost effective remediation strategy. The primary focus of this research is to determine the mechanisms by which the fluxes of electron acceptors, electron donors, and other species can be controlled to maximize the transfer of reductive equivalents to the aqueous and solid phases. The proposed research is unique in the NABIR portfolio in that it focuses on (i) the role of flow and transport in the initiation of biostimulation and the successful sequestration of metals and radionuclides [specifically U(VI)], (ii) the subsequent reductive capacity and stability of the reduced sediments produced by the biostimulation process, and (iii) the potential for altering the growth of biomass in the subsurface by the addition of specific metabolic uncoupling compounds. A scientifically-based understanding of these phenomena are critical to the ability to design successful bioremediation schemes.The laboratory research will employ Shewanella putrefaciens (CN32), a facultative DMRB that can use Fe(III) oxides as a terminal electron acceptor. Sediment-packed columns will be inoculated with this organism, and the reduction of U(VI) by the DMRB will be stimulated by the addition of a carbon and energy source in the presence of Fe(III). Separate column experiments will be conducted to independently examine: (1) the importance of the abiotic reduction of U(VI) by biogenic Fe(II); (2) the influence of the transport process on Fe(III) reduction and U(VI) immobilization, with emphasis on methods for controlling the fluxes of aqueous species to maximize uranium reduction; (3) the reductive capacity of biologicallyreduced sediments (with respect to re-oxidation by convective fluxes of O 2 and NO 3 -) and the long-term stability of immobilized uranium mineral phases after bioremediation processes are complete, and (4) the ability for metabolic uncoupling compounds to maintain microbial growth while limiting biomass production. The results of the laboratory experiments will be used to develop mathematical descriptive models for the coupled transport and reduction processes.This research is based on three areas of scientific research focused around the theme of coupling DMRB-mediated redox process, chemical transport, and control of microbial growth. The hypotheses associated with these themes can be stated as follows.

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“…For instance, quanti¢ed information about the model parameters may be helpful in designing the optimal medium and reactor operating conditions. In our chosen example, Liu et al looked at the e¡ect of residual methanol concentration on the speci¢c production rate of acetic acid in a nitrogen-limiting continuous culture of a Bacillus strain [13]. The authors show that the kinetics are consistent with Michaelis^Menten type kinetics.…”

Section: Bayesian Experimental Design Is a Generic Approachmentioning

confidence: 99%

Efficient and cost‐effective experimental determination of kinetic constants and data: the success of a Bayesian systematic approach to drug transport, receptor binding, continuous culture and cell transport kinetics

2003

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Details about the parameters of kinetic systems are crucial for progress in both medical and industrial research, including drug development, clinical diagnosis and biotechnology applications. Such details must be collected by a series of kinetic experiments and investigations. The correct design of the experiment is essential to collecting data suitable for analysis, modelling and deriving the correct information. We have developed a systematic and iterative Bayesian method and sets of rules for the design of enzyme kinetic experiments. Our method selects the optimum design to collect data suitable for accurate modelling and analysis and minimises the error in the parameters estimated. The rules select features of the design such as the substrate range and the number of measurements. We show here that this method can be directly applied to the study of other important kinetic systems, including drug transport, receptor binding, microbial culture and cell transport kinetics. It is possible to reduce the errors in the estimated parameters and, most importantly, increase the e⁄ciency and cost-e¡ectiveness by reducing the necessary amount of experiments and data points measured.

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A kinetic model for energy spilling-associated product formation in substrate-sufficient continuous culture

Cited by 9 publications

References 15 publications

Reduction in excess sludge production by addition of chemical uncouplers in activated sludge batch cultures

Reduction in excess sludge production by addition of chemical uncouplers in activated sludge batch cultures

Influence of Reactive Transport on the Reduction of U(VI) in the Presence of Fe(III) and Nitrate: Implications for U(VI) Immobilization by Bioremediation / Biobarriers- Final Report

Efficient and cost‐effective experimental determination of kinetic constants and data: the success of a Bayesian systematic approach to drug transport, receptor binding, continuous culture and cell transport kinetics

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