A mathematical model for electrochemically active filamentous sulfide-oxidising bacteria

Fischer, Keelan; Batstone, Damien J.; Loosdrecht, M.C.M. van; Picioreanu, Cristian

doi:10.1016/j.bioelechem.2014.11.002

Cited by 11 publications

(8 citation statements)

References 23 publications

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“…The model proposed in this work decouples and links the hydrogen oxidation (e.g., catabolic and anabolic) with nitrogen oxides compound reduction processes (from NO À 3 to N 2 via NO À 2 , NO, and N 2 O) through the introduction of electron carriers during the electron transfer processes , to describe all potential | 979 (Gyan, Shiohira, Sato, Takeuchi, & Sato, 2006), the continued availability of Mred and Mox depends on their concomitant regeneration, which is modeled by a recirculation loop between Mred and Mox (Mred ⇌ Mox + 2e − + 2H + ), that is, a decrease in Mred being offset by an increase in Mox and vice versa, with the total amount of electron carriers (C tot ) keeping constant (S Mred + S Mox = C tot ). This approach has also been widely applied for other biological systems with electron competition (Fischer, Batstone, van Loosdrecht, & Picioreanu, 2015). Further, the model parameters have become more unified, especially electron affinity constant during denitrification (Pan et al, 2015;Sabba, Picioreanu, & Nerenberg, 2017).…”

Section: Model Developmentmentioning

confidence: 99%

Modeling electron competition among nitrogen oxides reduction and N₂O accumulation in hydrogenotrophic denitrification

Liu

Ngo

Guo

et al. 2018

Biotech & Bioengineering

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Hydrogenotrophic denitrification is a novel and sustainable process for nitrogen removal, which utilizes hydrogen as electron donor, and carbon dioxide as carbon source. Recent studies have shown that nitrous oxide (N O), a highly undesirable intermediate and potent greenhouse gas, can accumulate during this process. In this work, a new mathematical model is developed to describe nitrogen oxides dynamics, especially N O, during hydrogenotrophic denitrification for the first time. The model describes electron competition among the four steps of hydrogenotrophic denitrification through decoupling hydrogen oxidation and nitrogen reduction processes using electron carriers, in contrast to the existing models that couple these two processes and also do not consider N O accumulation. The developed model satisfactorily describes experimental data on nitrogen oxides dynamics obtained from two independent hydrogenotrophic denitrifying cultures under various hydrogen and nitrogen oxides supplying conditions, suggesting the validity and applicability of the model. The results indicated that N O accumulation would not be intensified under hydrogen limiting conditions, due to the higher electron competition capacity of N O reduction in comparison to nitrate and nitrite reduction during hydrogenotrophic denitrification. The model is expected to enhance our understanding of the process during hydrogenotrophic denitrification and the ability to predict N O accumulation.

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Section: Model Developmentmentioning

confidence: 99%

Modeling electron competition among nitrogen oxides reduction and N₂O accumulation in hydrogenotrophic denitrification

Liu

Ngo

Guo

et al. 2018

Biotech & Bioengineering

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“…This system has been described mathematically (Fischer et al 2015), but it highlights the need for a generic framework transposable to any system of EAM.…”

Section: Natural Systemsmentioning

confidence: 99%

“…This approach allows connection between oxidation on the metal surface coupled with reduction in the biofilm. Electron sourcing/sinking ability is determined by the redox state of an intracellular mediator M (Fischer et al, 2015), which interacts with both the metabolic pathway and the conductive biofilm according to the local thermodynamics of the system. Electron transport from metal to the microorganism is assumed to involve one homogenous transfer (metal to the cell surface) and one heterogeneous transfer (cell surface-bound oxidised cytochrome to reduced cytochrome).…”

Section: Model Description Figure 31 (A) the Reaction Model Showinmentioning

confidence: 99%

“…The growth of the biofilm is then based upon substrate consumption thermodynamics (Heijnen and Kleerebezem, 2010;Fischer et al, 2015); this is fully described in Supplementary Information B.…”

Section: Biological Reactionsmentioning

confidence: 99%

“…Although the properties of this direct electron uptake have yet to be thoroughly analysed, previous modelling work has shown how the formation of conductive networks can be advantageous to bacteria, allowing cell metabolism to occur in situations where redox couples are physically separated (Fischer et al, 2015). While certain visualisations of electrochemically related features of SRB exist (e.g., conductive appendages (Sherar et al, 2011)), the overall electron transfer mechanism is yet to be conclusively determined.…”

Section: Introductionmentioning

confidence: 99%

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Mathematical modelling of electron transfer modes in electroactive microorganisms

Fischer¹

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Electroactive microorganisms (EAMs) are known to function in a variety of systems, and receive strong focus in scientific investigation; microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) are two key fields utilising these microorganisms to date. Microbially influenced corrosion (MIC) and the conduction of filamentous bacteria in ocean sediments also make use of external electrical currents to enable growth in what otherwise may be an abiotic environment. With the discovery of more of these systems and a growing understanding of their relevance over the past couple of decades, research into them has been steadily increasing. Electrochemical techniques such as cyclic voltammetry and impedance analysis have been used to gain a greater understanding of the system. However, mechanistic model-based analysis has lagged behind, with the fundamentals and consequences of electron transfer still not fully understood. Mechanistic investigation is vital for the progression and furthering of related research, and for highlighting the interactions occurring within EAMs, as many processes occur at a level that cannot be resolved by experimental systems. While a number of models have described extracellular electron transfer, in particular, for MFCs, none have analysed short-range electrontransfer mechanisms on a comparative basis. This thesis uses common finiteelement and electrochemical diffusive-reactive modelling techniques to investigate electroactive organisms in highly diverse environments. One such system is a filamentous sulfide-oxidising system in ocean sediment. Filamentous bacteria grow between sulfide-rich and oxygen-rich regions, transferring electrons between selfdetermined anodic and cathodic zones. Splitting of the metabolic pathway between partners allows growth to be determined thermodynamically rather than empirically, with bacteria releasing or consuming electrons depending upon the available substrate. This modelling approach determined that the bacteria, while electroactive, cannot grow with the rates seen experimentally, and highlighted that the current conceptual picture is incomplete. A similar approach is used to investigate microbially influenced corrosion, showing that direct electrical uptake greatly exacerbates corrosion when compared to a purely chemical system, due to the shifting of the electrical potential of the metal and the subsequent increase in electrochemical rates. This model of corrosion rates in carbon steel showed the variability with changing environmental conditions and bacterial activity, ranging from ii as little as 0.05 mm/yr to a very significant 1.5 mm/yr with highly aggressive biofilms.

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Modeling Microbial Electrosynthesis

Korth

2017

Bioelectrosynthesis

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Mathematical modeling is an overarching approach for assessing the complexity of microbial electrosynthesis (MES) and for complementing the relevant experimental research. By describing and linking compartments, components, and processes with appropriate mathematical equations, MES and the corresponding bioelectrodes and complete bioelectrochemical systems can be analyzed and predicted across several temporal and local scales. Thereby, insights into fundamental phenomena and mechanisms, in addition to process engineering and design can be obtained. However, a substantial lack of knowledge about extracellular electron transfer mechanisms and electrotrophic microorganisms presumably prevented the development of adequate models of MES, especially of biocathodes, so far. To propel efforts regarding this demanding task, this chapter provides a comprehensive overview of the relevant compartments, components and processes, appropriate model strategies, and a discussion on potential modeling pitfalls. By adapting an established approach to assessing the energetics of microorganism, an instruction for calculating stoichiometry, thermodynamics, and kinetics, with the example of electro-autotrophic growth at cathodes, is presented. Models of bioanodes and fundamental electrochemical equations are described to provided strategies for calculating cathodic electron-uptake reactions and connecting them to the microbial metabolism. Finally, differential equations are detailed for coupling the distinct compartments of a bioelectrochemical system. Although MES comprises anodic and cathodic reactions, the present chapter focuses on biocathodes representing a functional connection between cathode and electron-accepting microorganisms.

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A mathematical model for electrochemically active filamentous sulfide-oxidising bacteria

Cited by 11 publications

References 23 publications

Modeling electron competition among nitrogen oxides reduction and N₂O accumulation in hydrogenotrophic denitrification

Modeling electron competition among nitrogen oxides reduction and N₂O accumulation in hydrogenotrophic denitrification

Mathematical modelling of electron transfer modes in electroactive microorganisms

Modeling Microbial Electrosynthesis

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A mathematical model for electrochemically active filamentous sulfide-oxidising bacteria

Cited by 11 publications

References 23 publications

Modeling electron competition among nitrogen oxides reduction and N2O accumulation in hydrogenotrophic denitrification

Modeling electron competition among nitrogen oxides reduction and N2O accumulation in hydrogenotrophic denitrification

Mathematical modelling of electron transfer modes in electroactive microorganisms

Modeling Microbial Electrosynthesis

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Modeling electron competition among nitrogen oxides reduction and N₂O accumulation in hydrogenotrophic denitrification

Modeling electron competition among nitrogen oxides reduction and N₂O accumulation in hydrogenotrophic denitrification