Predation creates unique void layer in membrane-aerated biofilms

Aybar, Marcelo; Perez-Calleja, Patricia; Li, Mengfei; Pavissich, Juan Pablo; Nerenberg, Robert

doi:10.1016/j.watres.2018.10.084

Cited by 36 publications

(17 citation statements)

References 42 publications

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“…Our research suggests there is an optimal biofilm thickness for a given bulk NO 3 − concentration, that is one that results in a maximum NO 3 − flux with minimal NO 2 − accumulation. However, biofilms usually change thicknesses over time due to growth, detachment, and predation (Stewart, ; Martin & Nerenberg, ; Aybar, Perez‐Calleja, Li, Pavissich, & Nerenberg, ) and it is rarely possible to maintain a desired thickness. However, our results still have practical utility.…”

Section: Discussionmentioning

confidence: 99%

Using kinetics and modeling to predict denitrification fluxes in elemental‐sulfur‐based biofilms

Wang

Sabba

Bott

et al. 2019

Biotech & Bioengineering

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Elemental sulfur (S 0 ) can serve as an electron donor for water and wastewater denitrification, but few researchers have addressed the kinetics of S 0 -based reduction of nitrate (NO 3 − ), nitrite (NO 2 − ), and nitrous oxide (N 2 O). In addition, S 0based denitrifying biofilms are counter-diffusional. This is because the electron donor (S 0 ) is supplied from the biofilm attachment surface while the acceptor, for example, NO 3 − , is supplied from the bulk liquid. No existing mathematical model for S 0 -based denitrification considers this behavior. In this study, batch tests were used to determine the kinetic parameters for the reduction of NO 3 − , NO 2 − , and N 2 O.Additionally, a biofilm model was developed to explore the effects of counterdiffusion on overall fluxes, that is, the mass of NO 3 − or NO 2 − removed per unit biofilm support area per unit time. The maximum specific substrate utilization rates (q) for NO 3 − , NO 2 − , and N 2 O were 3.54, 1.98, and 6.28 g N g COD −1 ·d −1 , respectively. The maximum specific growth rates (μ) were 0.71, 1.21, and 1.67 d −1 for NO 3 − to NO 2 − , NO 2 − to N 2 O, and N 2 O to N 2 , respectively. Results suggest that the observed NO 2 − accumulation during S 0 -based denitrification results from a lowq for NO 2 − relative to that for NO 3 − . The highq for N 2 O, relative to that for NO 3 − and NO 2 − , suggest that little N 2 O accumulation occurs during denitrification. A counter-diffusional biofilm model was used to predict trends for NO 3 − fluxes, and confirmed NO 2 − accumulation in S 0 -based denitrification biofilms. It also explains the observed detrimental effects of biofilm thickness on denitrification fluxes. This study allows a more accurate prediction of NO 3 − , NO 2 − , and N 2 O transformations in S 0 -based denitrification.

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Section: Discussionmentioning

confidence: 99%

Using kinetics and modeling to predict denitrification fluxes in elemental‐sulfur‐based biofilms

Wang

Sabba

Bott

et al. 2019

Biotech & Bioengineering

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“…The growth medium (see Supporting Information Material SI) contained 100 mg/L of acetate as an electron donor and 15 μg/ml of gentamicin sulfate (Sigma‐Aldrich) to maintain axenic conditions. The P. aeruginosa biofilm was grown in a membrane‐aerated biofilm reactor, following Aybar, Perez‐Calleja, Li, Pavissich, and Nerenberg (2019). The biofilm was collected from the membrane after 2 weeks of growth when it was approximately 800 μm thick.…”

Section: Methodsmentioning

confidence: 99%

Predicting biofilm deformation with a viscoelastic phase‐field model: Modeling and experimental studies

Matouš

Nerenberg

2020

Biotech & Bioengineering

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Biofilms commonly develop in flowing aqueous environments, where the flow causes the biofilm to deform. Because biofilm deformation affects the flow regime, and because biofilms behave as complex heterogeneous viscoelastic materials, few models are able to predict biofilm deformation. In this study, a phase-field (PF) continuum model coupled with the Oldroyd-B constitutive equation was developed and used to simulate biofilm deformation. The accuracy of the model was evaluated using two types of biofilms: a synthetic biofilm, made from alginate mixed with bacterial cells, and a Pseudomonas aeruginosa biofilm. Shear rheometry was used to experimentally determine the mechanical parameters for each biofilm, used as inputs for the model. Biofilm deformation under fluid flow was monitored experimentally using optical coherence tomography. The comparison between the experimental and modeling geometries, for selected horizontal cross sections, after fluid-driven deformation was good. The relative errors ranged from 3.2 to 21.1% for the synthetic biofilm and from 9.1 to 11.1% for the P. aeruginosa biofilm. This is the first demonstration of the effectiveness of a viscoelastic PF biofilm model. This model provides an important tool for predicting biofilm viscoelastic deformation. It also can benefit the design and control of biofilms in engineering systems.

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“…Observations of natural and laboratory-grown biofilms as well as computer modeling of biofilm growth suggested that biofilm structure may be largely determined by the prevailing substrate concentration 33 and hydrodynamic conditions 34 . In natural and industrial ecosystem biofilms grazing by protozoa can also influence structure 35 . There may be a continuum between these types of biofilms as, for example, an increase in nutrient availability may cause a transition from sparsely colonized surfaces with heterogeneous biofilms to confluent and compact biofilms that correspond to the initial notion of biofilms as surface-covering biological layers.…”

Section: Biofilm—a Term Ready For the Next Leapmentioning

confidence: 99%

Who put the film in biofilm? The migration of a term from wastewater engineering to medicine and beyond

Flemming

Baveye²,

Neu

et al. 2021

npj Biofilms Microbiomes

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Sessile microorganisms were described as early as the seventeenth century. However, the term biofilm arose only in the 1960s in wastewater treatment research and was adopted later in marine fouling and in medical and dental microbiology. The sessile mode of microbial life was gradually recognized to be predominant on Earth, and the term biofilm became established for the growth of microorganisms in aggregates, frequently associated with interfaces, although many, if not the majority, of them not being continuous “films” in the strict sense. In this sessile form of life, microorganisms live in close proximity in a matrix of extracellular polymeric substances (EPS). They share emerging properties, clearly distinct from solitary free floating planktonic microbial cells. Common characteristics include the formation of synergistic microconsortia, using the EPS matrix as an external digestion system, the formation of gradients and high biodiversity over microscopically small distances, resource capture and retention, facilitated gene exchange as well as intercellular communication, and enhanced tolerance to antimicrobials. Thus, biofilms belong to the class of collective systems in biology, like forests, beehives, or coral reefs, although the term film addresses only one form of the various manifestations of microbial aggregates. The uncertainty of this term is discussed, and it is acknowledged that it will not likely be replaced soon, but it is recommended to understand these communities in the broader sense of microbial aggregates.

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Predation creates unique void layer in membrane-aerated biofilms

Cited by 36 publications

References 42 publications

Using kinetics and modeling to predict denitrification fluxes in elemental‐sulfur‐based biofilms

Using kinetics and modeling to predict denitrification fluxes in elemental‐sulfur‐based biofilms

Predicting biofilm deformation with a viscoelastic phase‐field model: Modeling and experimental studies

Who put the film in biofilm? The migration of a term from wastewater engineering to medicine and beyond

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