1
|
Philipp LA, Bühler K, Ulber R, Gescher J. Beneficial applications of biofilms. Nat Rev Microbiol 2024; 22:276-290. [PMID: 37957398 DOI: 10.1038/s41579-023-00985-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2023] [Indexed: 11/15/2023]
Abstract
Many microorganisms live in the form of a biofilm. Although they are feared in the medical sector, biofilms that are composed of non-pathogenic organisms can be highly beneficial in many applications, including the production of bulk and fine chemicals. Biofilm systems are natural retentostats in which the biocatalysts can adapt and optimize their metabolism to different conditions over time. The adherent nature of biofilms allows them to be used in continuous systems in which the hydraulic retention time is much shorter than the doubling time of the biocatalysts. Moreover, the resilience of organisms growing in biofilms, together with the potential of uncoupling growth from catalytic activity, offers a wide range of opportunities. The ability to work with continuous systems using a potentially self-advancing whole-cell biocatalyst is attracting interest from a range of disciplines, from applied microbiology to materials science and from bioengineering to process engineering. The field of beneficial biofilms is rapidly evolving, with an increasing number of applications being explored, and the surge in demand for sustainable and biobased solutions and processes is accelerating advances in the field. This Review provides an overview of the research topics, challenges, applications and future directions in beneficial and applied biofilm research.
Collapse
Affiliation(s)
- Laura-Alina Philipp
- Hamburg University of Technology, Institute of Technical Microbiology, Hamburg, Germany
| | - Katja Bühler
- Department of Environmental Microbiology, Helmholtz-Centre for Environmental Research, Leipzig, Germany
| | - Roland Ulber
- RPTU Kaiserslautern-Landau, Institute of Bioprocess Engineering, Kaiserslautern, Germany
| | - Johannes Gescher
- Hamburg University of Technology, Institute of Technical Microbiology, Hamburg, Germany.
| |
Collapse
|
2
|
Li M, Nahum Y, Matouš K, Stoodley P, Nerenberg R. Effects of biofilm heterogeneity on the apparent mechanical properties obtained by shear rheometry. Biotechnol Bioeng 2023; 120:553-561. [PMID: 36305479 DOI: 10.1002/bit.28276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 09/30/2022] [Accepted: 10/24/2022] [Indexed: 01/13/2023]
Abstract
Rheometry is an experimental technique widely used to determine the mechanical properties of biofilms. However, it characterizes the bulk mechanical behavior of the whole biofilm. The effects of biofilm mechanical heterogeneity on rheometry measurements are not known. We used laboratory experiments and computer modeling to explore the effects of biofilm mechanical heterogeneity on the results obtained by rheometry. A synthetic biofilm with layered mechanical properties was studied, and a viscoelastic biofilm theory was employed using the Kelvin-Voigt model. Agar gels with different concentrations were used to prepare the layered, heterogeneous biofilm, which was characterized for mechanical properties in shear mode with a rheometer. Both experiments and simulations indicated that the biofilm properties from rheometry were strongly biased by the weakest portion of the biofilm. The simulation results using linearly stratified mechanical properties from a previous study also showed that the weaker portions of the biofilm dominated the mechanical properties in creep tests. We note that the model can be used as a predictive tool to explore the mechanical behavior of complex biofilm structures beyond those accessible to experiments. Since most biofilms display some degree of mechanical heterogeneity, our results suggest caution should be used in the interpretation of rheometry data. It does not necessarily provide the "average" mechanical properties of the entire biofilm if the mechanical properties are stratified.
Collapse
Affiliation(s)
- Mengfei Li
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Yanina Nahum
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Karel Matouš
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana, USA
| | - Paul Stoodley
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA
- National Biofilm Innovation Centre (NBIC) and National Centre for Advanced Tribology at Southampton (nCATS), Mechanical Engineering, University of Southampton, Southampton, United Kingdom
| | - Robert Nerenberg
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| |
Collapse
|
3
|
Candry P, Godfrey BJ, Wang Z, Sabba F, Dieppa E, Fudge J, Balogun O, Wells G, Winkler MKH. Tailoring polyvinyl alcohol-sodium alginate (PVA-SA) hydrogel beads by controlling crosslinking pH and time. Sci Rep 2022; 12:20822. [PMID: 36460678 PMCID: PMC9718846 DOI: 10.1038/s41598-022-25111-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 11/24/2022] [Indexed: 12/03/2022] Open
Abstract
Hydrogel-encapsulated catalysts are an attractive tool for low-cost intensification of (bio)-processes. Polyvinyl alcohol-sodium alginate hydrogels crosslinked with boric acid and post-cured with sulfate (PVA-SA-BS) have been applied in bioproduction and water treatment processes, but the low pH required for crosslinking may negatively affect biocatalyst functionality. Here, we investigate how crosslinking pH (3, 4, and 5) and time (1, 2, and 8 h) affect the physicochemical, elastic, and process properties of PVA-SA-BS beads. Overall, bead properties were most affected by crosslinking pH. Beads produced at pH 3 and 4 were smaller and contained larger internal cavities, while optical coherence tomography suggested polymer cross-linking density was higher. Optical coherence elastography revealed PVA-SA-BS beads produced at pH 3 and 4 were stiffer than pH 5 beads. Dextran Blue release showed that pH 3-produced beads enabled higher diffusion rates and were more porous. Last, over a 28-day incubation, pH 3 and 4 beads lost more microspheres (as cell proxies) than beads produced at pH 5, while the latter released more polymer material. Overall, this study provides a path forward to tailor PVA-SA-BS hydrogel bead properties towards a broad range of applications, such as chemical, enzymatic, and microbially catalyzed (bio)-processes.
Collapse
Affiliation(s)
- Pieter Candry
- grid.34477.330000000122986657Civil and Environmental Engineering, University of Washington, 201 More Hall, Box 352700, Seattle, WA 98195-2700 USA
| | - Bruce J. Godfrey
- grid.34477.330000000122986657Civil and Environmental Engineering, University of Washington, 201 More Hall, Box 352700, Seattle, WA 98195-2700 USA
| | - Ziwei Wang
- grid.16753.360000 0001 2299 3507Mechanical Engineering Department, Northwestern University, Evanston, IL 60208 USA
| | | | - Evan Dieppa
- grid.16753.360000 0001 2299 3507Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL 60208 USA
| | - Julia Fudge
- grid.34477.330000000122986657Civil and Environmental Engineering, University of Washington, 201 More Hall, Box 352700, Seattle, WA 98195-2700 USA
| | - Oluwaseyi Balogun
- grid.16753.360000 0001 2299 3507Mechanical Engineering Department, Northwestern University, Evanston, IL 60208 USA ,grid.16753.360000 0001 2299 3507Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208 USA
| | - George Wells
- grid.16753.360000 0001 2299 3507Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208 USA
| | - Mari-Karoliina Henriikka Winkler
- grid.34477.330000000122986657Civil and Environmental Engineering, University of Washington, 201 More Hall, Box 352700, Seattle, WA 98195-2700 USA
| |
Collapse
|
4
|
Synthetic periphyton as a model system to understand species dynamics in complex microbial freshwater communities. NPJ Biofilms Microbiomes 2022; 8:61. [PMID: 35869094 PMCID: PMC9307524 DOI: 10.1038/s41522-022-00322-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 07/01/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractPhototrophic biofilms, also known as periphyton, are microbial freshwater communities that drive crucial ecological processes in streams and lakes. Gaining a deep mechanistic understanding of the biological processes occurring in natural periphyton remains challenging due to the high complexity and variability of such communities. To address this challenge, we rationally developed a workflow to construct a synthetic community by co-culturing 26 phototrophic species (i.e., diatoms, green algae, and cyanobacteria) that were inoculated in a successional sequence to create a periphytic biofilm on glass slides. We show that this community is diverse, stable, and highly reproducible in terms of microbial composition, function, and 3D spatial structure of the biofilm. We also demonstrate the ability to monitor microbial dynamics at the single species level during periphyton development and how their abundances are impacted by stressors such as increased temperature and a herbicide, singly and in combination. Overall, such a synthetic periphyton, grown under controlled conditions, can be used as a model system for theory testing through targeted manipulation.
Collapse
|
5
|
Gierl L, Horn H, Wagner M. Impact of Fe 2+ and Shear Stress on the Development and Mesoscopic Structure of Biofilms-A Bacillus subtilis Case Study. Microorganisms 2022; 10:2234. [PMID: 36422304 PMCID: PMC9699539 DOI: 10.3390/microorganisms10112234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/04/2022] [Accepted: 11/07/2022] [Indexed: 07/25/2023] Open
Abstract
Bivalent cations are known to affect the structural and mechanical properties of biofilms. In order to reveal the impact of Fe2+ ions within the cultivation medium on biofilm development, structure and stability, Bacillus subtilis biofilms were cultivated in mini-fluidic flow cells. Two different Fe2+ inflow concentrations (0.25 and 2.5 mg/L, respectively) and wall shear stress levels (0.05 and 0.27 Pa, respectively) were tested. Mesoscopic biofilm structure was determined daily in situ and non-invasively by means of optical coherence tomography. A set of ten structural parameters was used to quantify biofilm structure, its development and change. The study focused on characterizing biofilm structure and development at the mesoscale (mm-range). Therefore, biofilm replicates (n = 10) were cultivated and analyzed. Three hypotheses were defined in order to estimate the effect of Fe2+ inflow concentration and/or wall shear stress on biofilm development and structure, respectively. It was not the intention to investigate and describe the underlying mechanisms of iron incorporation as this would require a different set of tools applied at microscopic levels as well as the use of, i.e., omic approaches. Fe2+ addition influenced biofilm development (e.g., biofilm accumulation) and structure markedly. Experiments revealed the accumulation of FeO(OH) within the biofilm matrix and a positive correlation of Fe2+ inflow concentration and biofilm accumulation. In more detail, independent of the wall shear stress applied during cultivation, biofilms grew approximately four times thicker at 2.5 mg Fe2+/L (44.8 µmol/L; high inflow concentration) compared to the low Fe2+ inflow concentration of 0.25 mg Fe2+/L (4.48 µmol/L). This finding was statistically verified (Scheirer-Ray-Hare test, ANOVA) and hints at a higher stability of Bacillus subtilis biofilms (e.g., elevated cohesive and adhesive strength) when grown at elevated Fe2+ inflow concentrations.
Collapse
Affiliation(s)
- Luisa Gierl
- Water Chemistry and Water Technology, Engler-Bunte-Institut, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9a, 76131 Karlsruhe, Germany
| | - Harald Horn
- Water Chemistry and Water Technology, Engler-Bunte-Institut, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9a, 76131 Karlsruhe, Germany
- German Technical and Scientific Association for Gas and Water (DVGW) Research Site at Karlsruhe Institute of Technology, Water Chemistry and Water Technology, Engler-Bunte-Ring 9a, 76131 Karlsruhe, Germany
| | - Michael Wagner
- Water Chemistry and Water Technology, Engler-Bunte-Institut, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9a, 76131 Karlsruhe, Germany
- Institute of Biological Interfaces (IBG-1), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| |
Collapse
|
6
|
Häuser L, Erben J, Pillot G, Kerzenmacher S, Dreher W, Küstermann E. In vivo characterization of electroactive biofilms inside porous electrodes with MR Imaging. RSC Adv 2022; 12:17784-17793. [PMID: 35765339 PMCID: PMC9199086 DOI: 10.1039/d2ra01162j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 05/30/2022] [Indexed: 12/03/2022] Open
Abstract
Identifying the limiting processes of electroactive biofilms is key to improve the performance of bioelectrochemical systems (BES). For modelling and developing BES, spatial information of transport phenomena and biofilm distribution are required and can be determined by Magnetic Resonance Imaging (MRI) in vivo, in situ and in operando even inside opaque porous electrodes. A custom bioelectrochemical cell was designed that allows MRI measurements with a spatial resolution of 50 μm inside a 500 μm thick porous carbon electrode. The MRI data showed that only a fraction of the electrode pore space is colonized by the Shewanella oneidensis MR-1 biofilm. The maximum biofilm density was observed inside the porous electrode close to the electrode-medium interface. Inside the biofilm, mass transport by diffusion is lowered down to 45% compared to the bulk growth medium. The presented data and the methods can be used for detailed models of bioelectrochemical systems and for the design of improved electrode structures. The use of magnetic resonance imaging can contribute to a better understanding of limiting processes occurring in electroactive biofilms especially inside opaque porous electrodes.![]()
Collapse
Affiliation(s)
- Luca Häuser
- Center for Environmental Research and Sustainable Technology (UFT), University of Bremen 28359 Bremen Germany
| | | | - Guillaume Pillot
- Center for Environmental Research and Sustainable Technology (UFT), University of Bremen 28359 Bremen Germany
| | - Sven Kerzenmacher
- Center for Environmental Research and Sustainable Technology (UFT), University of Bremen 28359 Bremen Germany
| | - Wolfgang Dreher
- In-vivo-MR Group, Faculty 02 (Biology/Chemistry), University of Bremen 28359 Bremen Germany
| | - Ekkehard Küstermann
- In-vivo-MR Group, Faculty 02 (Biology/Chemistry), University of Bremen 28359 Bremen Germany
| |
Collapse
|
7
|
Sonawane JM, Rai AK, Sharma M, Tripathi M, Prasad R. Microbial biofilms: Recent advances and progress in environmental bioremediation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 824:153843. [PMID: 35176385 DOI: 10.1016/j.scitotenv.2022.153843] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/15/2022] [Accepted: 02/09/2022] [Indexed: 05/21/2023]
Abstract
Microbial biofilms are formed by adherence of the bacteria through their secreted polymer matrices. The major constituents of the polymer matrices are extracellular DNAs, proteins, polysaccharides. Biofilms have exhibited a promising role in the area of bioremediation. These activities can be further improved by tuning the parameters like quorum sensing, characteristics of the adhesion surface, and other environmental factors. Organic pollutants have created a global concern because of their long-term toxicity on human, marine, and animal life. These contaminants are not easily degradable and continue to prevail in the environment for an extended period. Biofilms are being used for the remediation of different pollutants, among which organic pollutants have been of significance. The bioremediation of organic contaminants using biofilms is an eco-friendly, cheap, and green process. However, the development of this technology demands knowledge on the mechanism of action of the microbes to form the biofilm, types of specific bacteria or fungi responsible for the degradation of a particular organic compound, and the mechanistic role of the biofilm in the degradation of the pollutants. This review puts forth a comprehensive summary of the role of microbial biofilms in the bioremediation of different environment-threatening organic pollutants.
Collapse
Affiliation(s)
- Jayesh M Sonawane
- Department of Chemistry, Alexandre-Vachon Pavilion, Laval University, Quebec G1V 0A6, Canada
| | - Ashutosh Kumar Rai
- Department of Biochemistry, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia
| | - Minaxi Sharma
- Department of Applied Biology, University of Science and Technology, Meghalaya, 793101, India
| | - Manikant Tripathi
- Biotechnology Program, Dr. Rammanohar Lohia Avadh University, Ayodhya 224001, Uttar Pradesh, India
| | - Ram Prasad
- Department of Botany, Mahatma Gandhi Central University, Motihari 845401, Bihar, India.
| |
Collapse
|
8
|
Savorana G, Słomka J, Stocker R, Rusconi R, Secchi E. A microfluidic platform for characterizing the structure and rheology of biofilm streamers. SOFT MATTER 2022; 18:3878-3890. [PMID: 35535650 PMCID: PMC9131465 DOI: 10.1039/d2sm00258b] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Biofilm formation is the most successful survival strategy for bacterial communities. In the biofilm lifestyle, bacteria embed themselves in a self-secreted matrix of extracellular polymeric substances (EPS), which acts as a shield against mechanical and chemical insults. When ambient flow is present, this viscoelastic scaffold can take a streamlined shape, forming biofilm filaments suspended in flow, called streamers. Streamers significantly disrupt the fluid flow by causing rapid clogging and affect transport in aquatic environments. Despite their relevance, the structural and rheological characterization of biofilm streamers is still at an early stage. In this work, we present a microfluidic platform that allows the reproducible growth of biofilm streamers in controlled physico-chemical conditions and the characterization of their biochemical composition, morphology, and rheology in situ. We employed isolated micropillars as nucleation sites for the growth of single biofilm streamers under the continuous flow of a diluted bacterial suspension. By combining fluorescent staining of the EPS components and epifluorescence microscopy, we were able to characterize the biochemical composition and morphology of the streamers. Additionally, we optimized a protocol to perform hydrodynamic stress tests in situ, by inducing controlled variations of the fluid shear stress exerted on the streamers by the flow. Thus, the reproducibility of the formation process and the testing protocol make it possible to perform several consistent experimental replicates that provide statistically significant information. By allowing the systematic investigation of the role of biochemical composition on the structure and rheology of streamers, this platform will advance our understanding of biofilm formation.
Collapse
Affiliation(s)
- Giovanni Savorana
- Institute of Environmental Engineering, ETH Zürich, 8093, Zürich, Switzerland.
| | - Jonasz Słomka
- Institute of Environmental Engineering, ETH Zürich, 8093, Zürich, Switzerland.
| | - Roman Stocker
- Institute of Environmental Engineering, ETH Zürich, 8093, Zürich, Switzerland.
| | - Roberto Rusconi
- Department of Biomedical Sciences, Humanitas University, 20072, Pieve Emanuele, MI, Italy
- IRCCS Humanitas Research Hospital, 20089, Rozzano, MI, Italy
| | - Eleonora Secchi
- Institute of Environmental Engineering, ETH Zürich, 8093, Zürich, Switzerland.
| |
Collapse
|
9
|
Understanding photosynthetic biofilm productivity and structure through 2D simulation. PLoS Comput Biol 2022; 18:e1009904. [PMID: 35377868 PMCID: PMC9037940 DOI: 10.1371/journal.pcbi.1009904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 04/25/2022] [Accepted: 02/09/2022] [Indexed: 11/30/2022] Open
Abstract
We present a spatial model describing the growth of a photosynthetic microalgae biofilm. In this 2D-model we consider photosynthesis, cell carbon accumulation, extracellular matrix excretion, and mortality. The rate of each of these mechanisms is given by kinetic laws regulated by light, nitrate, oxygen and inorganic carbon. The model is based on mixture theory and the behaviour of each component is defined on one hand by mass conservation, which takes into account biological features of the system, and on the other hand by conservation of momentum, which expresses the physical properties of the components. The model simulates the biofilm structural dynamics following an initial colonization phase. It shows that a 75 μm thick active region drives the biofilm development. We then determine the optimal harvesting period and biofilm height which maximize productivity. Finally, different harvesting patterns are tested and their effect on biofilm structure are discussed. The optimal strategy differs whether the objective is to recover the total biofilm or just the algal biomass. Microalgae have many industrial applications, ranging from aquaculture, pharmaceutics, food industry to green energy. Planktonic cultivation of microalgae is energy-consuming. Growing them under a biofilm form is a new trend with attracting promises. Biofilms are complex heterogeneous ecosystems composed of microorganisms embedded within a self-produced extracellular matrix and stuck to a surface. Most of the studies have focused on bacterial biofilms and knowledge about microalgae biofilms is still very limited. In this paper, we propose a mathematical model describing microalgae biofilm development. We simulate in 1D and 2D the impact of harvesting conditions on biofilm productivity. In agreement with available experimental observations, we find that there exist optimal frequencies and patterns that optimize the productivity. We also show that the optimal conditions differ whether for maximizing the productivity of microalgae or of the whole biofilm.
Collapse
|
10
|
Li M, Matouš K, Nerenberg R. Data-driven modeling of heterogeneous viscoelastic biofilms. Biotechnol Bioeng 2022; 119:1301-1313. [PMID: 35129209 DOI: 10.1002/bit.28056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 01/21/2022] [Accepted: 01/30/2022] [Indexed: 11/06/2022]
Abstract
Biofilms are typically heterogeneous in morphology, structure, and composition, resulting in non-uniform mechanical properties. The distribution of mechanical properties, in turn, determines the biofilm behavior, such as deformation and detachment. Most biofilm models neglect biofilm heterogeneity, especially at the microscale. In this study, an image-based modeling approach was developed to transform two-dimensional optical coherence tomography (OCT) biofilm images to a pixel-scale non-Newtonian viscosity map of the biofilm. The map was calibrated using the bulk viscosity data from rheometer tests, based on assumed maximum and minimum viscosities and a relationship between OCT image intensity signals and non-Newtonian viscosity. While not quantitatively measuring biofilm viscosity for each pixel, it allows a rational spatial allocation of viscosities within the biofilm: areas with lower cell density, e.g., voids, are assigned lower viscosities, and areas with high cell densities are assigned higher viscosities. The spatial distribution of non-Newtonian viscosity was applied in an established Oldroyd-B constitutive model and implemented using the phase-field continuum approach for the deformation and stress analysis. The heterogeneous model was able to predict deformations more accurately than a homogenous one. Stress distribution in the heterogeneous biofilm displayed better characteristics than that in the homogeneous one, because it is highly dependent on the viscosity distribution. This work, using a pixel-scale, image-based approach to map the mechanical heterogeneity of biofilms for computational deformation and stress analysis, provides a novel modeling approach that allows the consideration of biofilm structural and mechanical heterogeneity. Future research should better characterize the relationship between OCT signal and viscosity, and consider other constitutive models for biofilm mechanical behavior. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Mengfei Li
- University of Notre Dame, Department of Civil and Environmental Engineering and Earth Sciences, 156 Fitzpatrick Hall, Notre Dame, IN, 46556, USA
| | - Karel Matouš
- University of Notre Dame, Department of Aerospace and Mechanical Engineering, Notre Dame, IN, 46556, USA
| | - Robert Nerenberg
- University of Notre Dame, Department of Civil and Environmental Engineering and Earth Sciences, 156 Fitzpatrick Hall, Notre Dame, IN, 46556, USA
| |
Collapse
|
11
|
Sportelli MC, Kranz C, Mizaikoff B, Cioffi N. Recent advances on the spectroscopic characterization of microbial biofilms: A critical review. Anal Chim Acta 2022; 1195:339433. [DOI: 10.1016/j.aca.2022.339433] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 12/30/2021] [Accepted: 01/02/2022] [Indexed: 02/07/2023]
|
12
|
Low-Field Nuclear Magnetic Resonance Characteristics of Biofilm Development Process. Microorganisms 2021; 9:microorganisms9122466. [PMID: 34946068 PMCID: PMC8707105 DOI: 10.3390/microorganisms9122466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/17/2021] [Accepted: 11/24/2021] [Indexed: 11/22/2022] Open
Abstract
To in situ and noninvasively monitor the biofilm development process by low-field nuclear magnetic resonance (NMR), experiments should be made to determine the mechanisms responsible for the T2 signals of biofilm growth. In this paper, biofilms were cultivated in both fluid media and saturated porous media. T2 relaxation for each sample was measured to investigate the contribution of the related processes to T2 relaxation signals. In addition, OD values of bacterial cell suspensions were measured to provide the relative number of bacterial cells. We also obtained SEM photos of the biofilms after vacuum freeze-drying the pure sand and the sand with biofilm formation to confirm the space within the biofilm matrix and identify the existence of biofilm formation. The T2 relaxation distribution is strongly dependent on the density of the bacterial cells suspended in the fluid and the stage of biofilm development. The peak time and the peak percentage can be used as indicators of the biofilm growth states.
Collapse
|
13
|
Fan X, Zhu SS, Zhang XX, Ren HQ, Huang H. Revisiting the Microscopic Processes of Biofilm Formation on Organic Carriers: A Study under Variational Shear Stresses. ACS APPLIED BIO MATERIALS 2021; 4:5529-5541. [DOI: 10.1021/acsabm.1c00344] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xuan Fan
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Shan-Shan Zhu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Xu-Xiang Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Hong-Qiang Ren
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| | - Hui Huang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, Jiangsu, PR China
| |
Collapse
|
14
|
Asgharnejad H, Sarrafzadeh MH, Abhar-Shegofteh O, Khorshidi Nazloo E, Oh HM. Biomass quantification and 3-D topography reconstruction of microalgal biofilms using digital image processing. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102243] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
15
|
Zlotnicki J, Gabrielli A, Urish KL, Brothers KM. Clinical Evidence of Current Irrigation Practices and the Use of Oral Antibiotics to Prevent and Treat Periprosthetic Joint Infection. Orthop Clin North Am 2021; 52:93-101. [PMID: 33752842 PMCID: PMC7990073 DOI: 10.1016/j.ocl.2020.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Jason Zlotnicki
- Arthritis and Arthroplasty Design Group, Department of Orthopaedic Surgery, College of Medicine, University of Pittsburgh, Bridgeside Point II, 450 Technology Drive, Pittsburgh, PA 15219, USA
| | - Alexandra Gabrielli
- Arthritis and Arthroplasty Design Group, Department of Orthopaedic Surgery, College of Medicine, University of Pittsburgh, Bridgeside Point II, 450 Technology Drive, Pittsburgh, PA 15219, USA
| | - Kenneth L Urish
- Arthritis and Arthroplasty Design Group, Department of Orthopaedic Surgery, College of Medicine, University of Pittsburgh, Bridgeside Point II, 450 Technology Drive, Pittsburgh, PA 15219, USA
| | - Kimberly M Brothers
- Arthritis and Arthroplasty Design Group, Department of Orthopaedic Surgery, College of Medicine, University of Pittsburgh, Bridgeside Point II, 450 Technology Drive, Pittsburgh, PA 15219, USA.
| |
Collapse
|
16
|
Lequette K, Ait-Mouheb N, Adam N, Muffat-Jeandet M, Bru-Adan V, Wéry N. Effects of the chlorination and pressure flushing of drippers fed by reclaimed wastewater on biofouling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 758:143598. [PMID: 33213927 DOI: 10.1016/j.scitotenv.2020.143598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 10/29/2020] [Accepted: 10/29/2020] [Indexed: 06/11/2023]
Abstract
Milli-channel baffle labyrinths are widely used in drip irrigation systems. They induce a pressure drop enabling drip irrigation. However, with a section thickness that is measured in mm2, they are sensitive to clogging, which reduces the performance and service life of a drip irrigation system. The impact of chlorination (1.5 ppm of free chlorine during 1 h application) and pressure flushing (0.18 MPa) on the biofouling of non-pressure-compensating drippers, fed by real reclaimed wastewater, was studied at lab scale using optical coherence tomography. The effect of these treatments on microbial composition (bacteria and eukaryotes) was also investigated by High-throughput DNA sequencing. Biofouling was mainly observed in the inlet, outlet and return areas of the milli-labyrinth channel from drippers. Chlorination reduced biofilm development, particularly in the mainstream of the milli-labyrinth channel, and it was more efficient when combined with pressure flushing. Moreover, chlorination was more efficient in maintaining water distribution uniformity (CU < 95% compared to less than 85% for unchlorinated lines). It reduced more efficiently the bacterial concentration (≈1 log) and the diversity of the bacterial community in the dripper biofilms compared to the pressure flushing method. Chlorination significantly modified the microbial communities, promoting chlorine-resistant bacteria such as Comamonadaceae or Azospira. Inversely, several bacterial groups were identified as sensitive to chlorination such as Chloroflexi and Planctomycetes. Nevertheless, one month after stopping the treatments bacterial diversity recovered and the chlorine-sensitive bacteria such as Chloroflexi phylum and the Saprospiraceae, Spirochaetaceae, Christensenellaceae and Hydrogenophilaceae families re-emerged in conjunction with the growth of biofouling, highlighting the resilience of the bacteria originating from drippers. Based on PCoA analyses, the structure of the bacterial communities still clustered separately from non-chlorinated drippers, showing that the effect of chlorination was still detectable one month after stopping the treatment.
Collapse
Affiliation(s)
- Kévin Lequette
- INRAE, University of Montpellier, LBE, 102, Avenue des Etangs, 11100 Narbonne, France; INRAE, University of Montpellier, UMR G-EAU, Avenue Jean-François Breton, 34000 Montpellier, France
| | - Nassim Ait-Mouheb
- INRAE, University of Montpellier, UMR G-EAU, Avenue Jean-François Breton, 34000 Montpellier, France
| | - Nicolas Adam
- University of Toulouse, Centre de recherche Cerveau et Cognition, 31000 Toulouse, France
| | - Marine Muffat-Jeandet
- INRAE, University of Montpellier, UMR G-EAU, Avenue Jean-François Breton, 34000 Montpellier, France
| | - Valérie Bru-Adan
- INRAE, University of Montpellier, LBE, 102, Avenue des Etangs, 11100 Narbonne, France
| | - Nathalie Wéry
- INRAE, University of Montpellier, LBE, 102, Avenue des Etangs, 11100 Narbonne, France.
| |
Collapse
|
17
|
Felz S, Kleikamp H, Zlopasa J, van Loosdrecht MC, Lin Y. Impact of metal ions on structural EPS hydrogels from aerobic granular sludge. Biofilm 2020; 2:100011. [PMID: 33447798 PMCID: PMC7798472 DOI: 10.1016/j.bioflm.2019.100011] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/30/2019] [Accepted: 11/12/2019] [Indexed: 01/08/2023] Open
Abstract
Structural extracellular polymeric substances (structural EPS) can form stable hydrogels and are considered to be responsible for the stability of biofilms and aerobic granular sludge. Structural EPS were extracted from aerobic granular sludge and characterized for their gel-forming capacity with different alkaline earth and transition metal ions. The structural EPS hydrogels were compared to alginate hydrogels. Alginate is a well characterized polymer which is able to form stiff hydrogels with multivalent ions. The stiffness of the obtained hydrogels was measured with dynamic mechanical analysis and quantified by the Young's modulus. Furthermore the stability of structural EPS hydrogels towards disintegration in the presence of ethylenediaminetetraacetic acid (EDTA) was evaluated at pH 4.5-10.5 and compared to that of alginate, polygalacturonic acid and κ-carrageenan. The stiffness of alginate hydrogels was multiple times higher than that of structural EPS. Alkaline earth metals resulted in stiffer alginate hydrogels than transition metals. For structural EPS this trend was opposite to alginate. Independent of the pH, polysaccharide hydrogels were quickly disintegrated when being exposed to EDTA. Structural EPS hydrogels demonstrated greater stability towards EDTA and were still intact after one month at pH 4.5-8.5. It is suggested that the gelling mechanism of structural EPS is not only related to metal ion complexation of the polymers, but to a combination of interactions of multiple functional groups present in structural EPS. This study helps to further understand and characterize structural EPS from aerobic granular sludge, and therewith understand its stability and that of biofilms in general.
Collapse
Affiliation(s)
- Simon Felz
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Hugo Kleikamp
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Jure Zlopasa
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Mark C.M. van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Yuemei Lin
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| |
Collapse
|
18
|
Javier L, Farhat NM, Desmond P, Linares RV, Bucs S, Kruithof JC, Vrouwenvelder JS. Biofouling control by phosphorus limitation strongly depends on the assimilable organic carbon concentration. WATER RESEARCH 2020; 183:116051. [PMID: 32622233 DOI: 10.1016/j.watres.2020.116051] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 06/11/2020] [Accepted: 06/12/2020] [Indexed: 05/26/2023]
Abstract
Nutrient limitation is a biofouling control strategy in reverse osmosis (RO) membrane systems. In seawater, the assimilable organic carbon content available for bacterial growth ranges from about 50 to 400 μg C·L-1, while the phosphorus concentration ranges from 3 to 11 μg P·L-1. Several studies monitored biofouling development, limiting either carbon or phosphorus. The effect of carbon to phosphorus ratio and the restriction of both nutrients on membrane system performance have not yet been investigated. This study examines the impact of reduced phosphorus concentration (from 25 μg P·L-1 and 3 μg P·L-1, to a low concentration of ≤0.3 μg P·L-1), combined with two different carbon concentrations (250 C L-1 and 30 μg C·L-1), on biofilm development in an RO system. Feed channel pressure drop was measured to determine the effect of the developed biofilm on system performance. The morphology of the accumulated biomass for both carbon concentrations was characterized by optical coherence tomography (OCT) and the biomass amount and composition was quantified by measuring total organic carbon (TOC), adenosine triphosphate (ATP), total cell counts (TCC), and extracellular polymeric substances (EPS) concentration for the developed biofilms under phosphorus restricted (P-restricted) and dosed (P-dosed) conditions. For both carbon concentrations, P-restricted conditions (≤0.3 μg P·L-1) limited bacterial growth (lower values of ATP, TCC). A faster pressure drop increase was observed for P-restricted conditions compared to P-dosed conditions when 250 μg C·L-1 was dosed. This faster pressure drop increase can be explained by a higher area covered by biofilm in the flow channel and a higher amount of produced EPS. Conversely, a slower pressure drop increase was observed for P-restricted conditions compared to P-dosed conditions when 30 μg C·L-1 was dosed. Results of this study demonstrate that P-limitation delayed biofilm formation effectively when combined with low assimilable organic carbon concentration and thereby, lengthening the overall membrane system performance.
Collapse
Affiliation(s)
- Luisa Javier
- King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center (WDRC), Division of Biological and Environmental Science and Engineering (BESE), Thuwal, 23955-6900, Saudi Arabia
| | - Nadia M Farhat
- King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center (WDRC), Division of Biological and Environmental Science and Engineering (BESE), Thuwal, 23955-6900, Saudi Arabia.
| | - Peter Desmond
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
| | - Rodrigo Valladares Linares
- Renewable Energy Unit, Yucatan Center for Scientific Research (CICY), 43 Street #130, Chuburna de Hidalgo, 97205, Mérida, Yucatan, Mexico
| | - Szilárd Bucs
- King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center (WDRC), Division of Biological and Environmental Science and Engineering (BESE), Thuwal, 23955-6900, Saudi Arabia
| | - Joop C Kruithof
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, the Netherlands
| | - Johannes S Vrouwenvelder
- King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center (WDRC), Division of Biological and Environmental Science and Engineering (BESE), Thuwal, 23955-6900, Saudi Arabia; Delft University of Technology, Faculty of Applied Sciences, Department of Biotechnology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| |
Collapse
|
19
|
Li M, Matouš K, Nerenberg R. Predicting biofilm deformation with a viscoelastic phase‐field model: Modeling and experimental studies. Biotechnol Bioeng 2020; 117:3486-3498. [DOI: 10.1002/bit.27491] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/18/2020] [Accepted: 07/10/2020] [Indexed: 01/27/2023]
Affiliation(s)
- Mengfei Li
- Department of Civil and Environmental Engineering and Earth Sciences University of Notre Dame Notre Dame Indiana
| | - Karel Matouš
- Department of Aerospace and Mechanical Engineering University of Notre Dame Notre Dame Indiana
| | - Robert Nerenberg
- Department of Civil and Environmental Engineering and Earth Sciences University of Notre Dame Notre Dame Indiana
| |
Collapse
|
20
|
An open-source robotic platform that enables automated monitoring of replicate biofilm cultivations using optical coherence tomography. NPJ Biofilms Microbiomes 2020; 6:18. [PMID: 32238809 PMCID: PMC7113294 DOI: 10.1038/s41522-020-0129-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 03/06/2020] [Indexed: 12/14/2022] Open
Abstract
The paper introduces a fully automated cultivation and monitoring tool to study biofilm development in replicate experiments operated in parallel. To gain a fundamental understanding of the relation between cultivation conditions and biofilm characteristics (e.g., structural, mechanical) a monitoring setup allowing for the standardization of methods is required. Optical coherence tomography (OCT) is an imaging modality ideal for biofilms since it allows for the monitoring of structure in real time. By integrating an OCT device into the open-source robotic platform EvoBot, a fully automated monitoring platform for investigating biofilm development in several flow cells at once was realized. Different positioning scenarios were tested and revealed that the positioning accuracy is within the optical resolution of the OCT. On that account, a reliable and accurate monitoring of biofilm development by means of OCT has become possible. With this robotic platform, reproducible biofilm experiments including a statistical analysis are achievable with only a small investment of operator time. Furthermore, a number of structural parameters calculated within this study confirmed the necessity to perform replicate biofilm cultivations.
Collapse
|
21
|
Xiao Y, Sawicka B, Liu Y, Zhou B, Hou P, Li Y. Visualizing the macroscale spatial distributions of biofilms in complex flow channels using industrial computed tomography. BIOFOULING 2020; 36:115-125. [PMID: 32090601 DOI: 10.1080/08927014.2020.1728260] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 02/01/2020] [Accepted: 02/04/2020] [Indexed: 06/10/2023]
Abstract
The presence of biofilms in enclosed pipelines can lead to numerous deleterious issues. To date, it has been difficult to use optical imaging techniques to monitor the macroscale spatial distributions of biofilms. To address this concern, a combination of industrial computed tomography (ICT) and a contrast agent was explored to noninvasively visualize biofilms in three types of drip irrigation emitters. The results showed that ICT successfully observed and quantified the macroscale spatial distributions of biofilms. The complex hydrodynamic characteristics in the emitter channels affected the local distributions of biofilms. Biofilms were mainly attached to the lateral and medial faces and biomass decreased along the flow directions. Based on the distributions of biofilms, some emitter structural design defects were further diagnosed. Applying ICT in combination with the contrast agent could potentially provide a visual and effective way to reveal the formation mechanisms of biofilms and to optimize flow channel structures to avoid biofilm accumulations.
Collapse
Affiliation(s)
- Yang Xiao
- College of Water Resources and Civil Engineering, China Agricultural University, Beijing, PR China
| | - Barbara Sawicka
- Department of Plant Production Technology and Commodities Science, University of Life Sciences, Lublin, Poland
| | - Yaoze Liu
- Department of Environmental and Sustainable Engineering, University at Albany, State University of New York, Albany, NY, USA
| | - Bo Zhou
- College of Water Resources and Civil Engineering, China Agricultural University, Beijing, PR China
| | - Peng Hou
- College of Water Resources and Civil Engineering, China Agricultural University, Beijing, PR China
| | - Yunkai Li
- College of Water Resources and Civil Engineering, China Agricultural University, Beijing, PR China
| |
Collapse
|
22
|
Cattò C, Cappitelli F. Testing Anti-Biofilm Polymeric Surfaces: Where to Start? Int J Mol Sci 2019; 20:E3794. [PMID: 31382580 PMCID: PMC6696330 DOI: 10.3390/ijms20153794] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 08/02/2019] [Indexed: 12/11/2022] Open
Abstract
Present day awareness of biofilm colonization on polymeric surfaces has prompted the scientific community to develop an ever-increasing number of new materials with anti-biofilm features. However, compared to the large amount of work put into discovering potent biofilm inhibitors, only a small number of papers deal with their validation, a critical step in the translation of research into practical applications. This is due to the lack of standardized testing methods and/or of well-controlled in vivo studies that show biofilm prevention on polymeric surfaces; furthermore, there has been little correlation with the reduced incidence of material deterioration. Here an overview of the most common methods for studying biofilms and for testing the anti-biofilm properties of new surfaces is provided.
Collapse
Affiliation(s)
- Cristina Cattò
- Department of Food Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy
| | - Francesca Cappitelli
- Department of Food Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy.
| |
Collapse
|
23
|
Kerdi S, Qamar A, Alpatova A, Ghaffour N. An in-situ technique for the direct structural characterization of biofouling in membrane filtration. J Memb Sci 2019. [DOI: 10.1016/j.memsci.2019.04.051] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
24
|
Jafari M, Derlon N, Desmond P, van Loosdrecht MCM, Morgenroth E, Picioreanu C. Biofilm compressibility in ultrafiltration: A relation between biofilm morphology, mechanics and hydraulic resistance. WATER RESEARCH 2019; 157:335-345. [PMID: 30965160 DOI: 10.1016/j.watres.2019.03.073] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 02/22/2019] [Accepted: 03/01/2019] [Indexed: 06/09/2023]
Abstract
Poroelastic fluid-structure interaction models were coupled to experimental data to determine the effects of biofilm spatial distribution of mechanical and hydraulic properties on the biofilm hydraulic resistance and compressibility in membrane filtration processes. Biofilms were cultivated on ultrafiltration membranes for 20 and 30 days under high (0.28 bar) and low (0.06 bar) transmembrane pressure (TMP), in dead-end filtration mode. Subsequently, biofilms were subjected to a compression/relaxation cycles by step-wise TMP changes. Structural deformation of biofilms during compression was observed in-situ using optical coherence tomography. Experimental results show that the observed increase in the biofilm hydraulic resistance during compression is not necessarily accompanied by a detectable biofilm thickness reduction. A dual-layer biofilm model with a dense base and porous top layer could explain these observed results. Because porosity controls indirectly the mechanical response of biofilms under compression, results could be described without assuming a gradient in mechanical properties within the biofilm. The biofilm surface roughness did not significantly influence the water flux in this study. However, the fraction of biofilm base layer directly exposed to bulk liquid could be a good indicator in the determination of water flux. The main implications of this study for the design and operation of low-pressure membrane systems (e.g., MF and UF with fouling layer being the main filtration resistance) lays in the selection of favorable operational TMP and biofilm morphology.
Collapse
Affiliation(s)
- Morez Jafari
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands.
| | - Nicolas Derlon
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland
| | - Peter Desmond
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| | - Eberhard Morgenroth
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
| | - Cristian Picioreanu
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, the Netherlands
| |
Collapse
|
25
|
Biofilm systems as tools in biotechnological production. Appl Microbiol Biotechnol 2019; 103:5095-5103. [PMID: 31079168 DOI: 10.1007/s00253-019-09869-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 04/23/2019] [Accepted: 04/24/2019] [Indexed: 01/08/2023]
Abstract
The literature provides more and more examples of research projects that develop novel production processes based on microorganisms organized in the form of biofilms. Biofilms are aggregates of microorganisms that are attached to interfaces. These viscoelastic aggregates of cells are held together and are embedded in a matrix consisting of multiple carbohydrate polymers as well as proteins. Biofilms are characterized by a very high cell density and by a natural retentostat behavior. Both factors can contribute to high productivities and a facilitated separation of the desired end-product from the catalytic biomass. Within the biofilm matrix, stable gradients of substrates and products form, which can lead to a differentiation and adaptation of the microorganisms' physiology to the specific process conditions. Moreover, growth in a biofilm state is often accompanied by a higher resistance and resilience towards toxic or growth inhibiting substances and factors. In this short review, we summarize how biofilms can be studied and what most promising niches for their application can be. Moreover, we highlight future research directions that will accelerate the advent of productive biofilms in biology-based production processes.
Collapse
|
26
|
Picioreanu C, Blauert F, Horn H, Wagner M. Determination of mechanical properties of biofilms by modelling the deformation measured using optical coherence tomography. WATER RESEARCH 2018; 145:588-598. [PMID: 30199803 DOI: 10.1016/j.watres.2018.08.070] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 08/25/2018] [Accepted: 08/30/2018] [Indexed: 05/28/2023]
Abstract
The advantage of using non-invasive imaging such as optical coherence tomography (OCT) to asses material properties from deformed biofilm geometries can be compromised by the assumptions made on fluid forces acting on the biofilm. This study developed a method for the determination of elastic properties of biofilms by modelling the biofilm deformation recorded by OCT imaging with poroelastic fluid-structure interaction computations. Two-dimensional biofilm geometries were extracted from OCT scans of non-deformed and deformed structures as a result of hydrodynamic loading. The biofilm geometries were implemented in a model coupling fluid dynamics with elastic solid mechanics and Darcy flow in the biofilm. The simulation results were compared with real deformed geometries and a fitting procedure allowed estimation of the Young's modulus in given flow conditions. The present method considerably improves the estimation of elastic moduli of biofilms grown in mini-fluidic rectangular channels. This superior prediction is based on the relaxation of several simplifying assumptions made in past studies: shear stress is not anymore taken constant over the biofilm surface, total stress including also pressure is accounted for, any biofilm shape can be used in the determinations, and non-linear behavior of mechanical properties can be estimated. Biofilm elastic moduli between 70 and 700 Pa were obtained and biofilm hardening at large applied stress due to increasing flow velocity was quantified. The work performed here opens the way for in-situ determination of other mechanical properties (e.g., viscoelastic properties, relaxation times, plastic yields) and provides data for modelling biofilm deformation and detachment with eventual applications in biofilm control and removal strategies.
Collapse
Affiliation(s)
- Cristian Picioreanu
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands.
| | - Florian Blauert
- Water Chemistry and Water Technology, Engler-Bunte-Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Harald Horn
- Water Chemistry and Water Technology, Engler-Bunte-Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Michael Wagner
- Water Chemistry and Water Technology, Engler-Bunte-Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| |
Collapse
|
27
|
Jafari M, Desmond P, van Loosdrecht MCM, Derlon N, Morgenroth E, Picioreanu C. Effect of biofilm structural deformation on hydraulic resistance during ultrafiltration: A numerical and experimental study. WATER RESEARCH 2018; 145:375-387. [PMID: 30173098 DOI: 10.1016/j.watres.2018.08.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/14/2018] [Accepted: 08/18/2018] [Indexed: 06/08/2023]
Abstract
Biofilm formation in membrane systems negatively impacts the filtration system performances. This study evaluated how biofilm compression driven by permeate flow increases the hydraulic resistance and leads to reduction in permeate flux. We analysed the effect of biofilm compression on hydraulic resistance and permeate flux through computational models supported by experimental data. Biofilms with homogeneous surface structure were subjected to step-wise changes in flux and transmembrane pressure during compression and relaxation tests. Biofilm thickness under applied forces was measured non-invasively in-situ using optical coherence tomography (OCT). A numerical model of poroelasticity, which couples water flow through the biofilm with biofilm mechanics, was developed to correlate the structural deformation with biofilm hydraulics (permeability and resistance). The computational model enabled extracting mechanical and hydrological parameters corresponding to the experimental data. Homogeneous biofilms under elevated compression forces experienced a significant reduction in thickness while only a slight increase in resistance was observed. This shows that hydraulic resistance of homogeneous biofilms was affected more by permeability decrease due to pore closure than by a decrease in thickness. Both viscoelastic and elastoplastic models could describe well the permanent biofilm deformation. However, for biofilms under study, a simpler elastic model could also be used due to the small irreversible deformations. The elastic moduli fitting the measured data were in agreement with other reported values for biofilm under compression. Biofilm stiffening under larger flow-driven compression forces was observed and described numerically by correlating inversely the elastic modulus with biofilm porosity. The importance of this newly developed method lies in estimation of accurate biofilm mechanical parameters to be used in numerical models for both membrane filtration system and biofouling cleaning strategies. Such model can ultimately be used to identify optimal operating conditions for membrane system subjected to biofouling.
Collapse
Affiliation(s)
- Morez Jafari
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, The Netherlands.
| | - Peter Desmond
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, The Netherlands
| | - Nicolas Derlon
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland
| | - Eberhard Morgenroth
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
| | - Cristian Picioreanu
- Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629, HZ, Delft, The Netherlands
| |
Collapse
|
28
|
Desmond P, Morgenroth E, Derlon N. Physical structure determines compression of membrane biofilms during Gravity Driven Membrane (GDM) ultrafiltration. WATER RESEARCH 2018; 143:539-549. [PMID: 30007257 DOI: 10.1016/j.watres.2018.07.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 06/21/2018] [Accepted: 07/04/2018] [Indexed: 06/08/2023]
Abstract
Increasing transmembrane pressure (TMP) can compress and increase the hydraulic resistance of membrane biofilms. The purpose of the present study is to evaluate how compression of membrane biofilms occurs and how structural rearrangement can affect hydraulic resistance. Biofilms with heterogeneous and homogeneous physical structures were grown in membrane fouling simulators (MFS) in dead-end mode for 20 days with either (i) a nutrient enriched condition with a nutrient ratio of 100:30:10 (C: N: P), (ii) a phosphorus limitation (C: N: P ratio: 100:30:0), or (iii) river water (C: N: P ratio: ca. 100:10:1). The structural and hydraulic response of membrane biofilms to (a) changes in transmembrane pressures (0.06-0.1-0.5-0.1-0.06 bar) and (b) changes in permeate flux (10-15-20-15-10 L/m2/h) were investigated. Optical coherence tomography (OCT) was used to monitor biofilm structural response, and OCT images were processed to quantify changes in the mean biofilm thickness and relative roughness. Nutrient enriched and river water biofilms had heterogeneous physical structures with greater surface roughness (Ra' > 0.2) than homogeneous P limiting biofilms (Ra' < 0.2). Compression of biofilms with rough heterogeneous structures (Ra' > 0.2) was irreversible, indicated by irreversible decrease in surface roughness, partial relaxation in mean biofilm thickness and irreversible increase in hydraulic resistance. Compression of homogeneous biofilm (Ra' < 0.2) was on the other hand reversible, indicated by full relaxation of the biofilms structure and restoration of initial hydraulic resistance. Hydraulic response (i.e., change in the specific biofilm resistance) did not correspond with the change in physical structure of heterogeneous biofilms. The presented study provides a fundamental understanding of how biofilm physical structure can affect the biofilm's response to a change in TMP, with practical relevance for the operation of GDM filtration systems.
Collapse
Affiliation(s)
- Peter Desmond
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland.
| | - Eberhard Morgenroth
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland; ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland.
| | - Nicolas Derlon
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland.
| |
Collapse
|
29
|
Desmond P, Böni L, Fischer P, Morgenroth E, Derlon N. Stratification in the physical structure and cohesion of membrane biofilms — Implications for hydraulic resistance. J Memb Sci 2018. [DOI: 10.1016/j.memsci.2018.07.088] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
30
|
Towards standardized mechanical characterization of microbial biofilms: analysis and critical review. NPJ Biofilms Microbiomes 2018; 4:17. [PMID: 30131867 PMCID: PMC6102240 DOI: 10.1038/s41522-018-0062-5] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 02/05/2023] Open
Abstract
Developing reliable anti-biofilm strategies or efficient biofilm-based bioprocesses strongly depends on having a clear understanding of the mechanisms underlying biofilm development, and knowledge of the relevant mechanical parameters describing microbial biofilm behavior. Many varied mechanical testing methods are available to assess these parameters. The mechanical properties thus identified can then be used to compare protocols such as antibiotic screening. However, the lack of standardization in both mechanical testing and the associated identification methods for a given microbiological goal remains a blind spot in the biofilm community. The pursuit of standardization is problematic, as biofilms are living structures, i.e., both complex and dynamic. Here, we review the main available methods for characterizing the mechanical properties of biofilms through the lens of the relationship linking experimental testing to the identification of mechanical parameters. We propose guidelines for characterizing biofilms according to microbiological objectives that will help the reader choose an appropriate test and a relevant identification method for measuring any given mechanical parameter. The use of a common methodology for the mechanical characterization of biofilms will enable reliable analysis and comparison of microbiological protocols needed for improvement of engineering process and screening.
Collapse
|
31
|
Magana M, Sereti C, Ioannidis A, Mitchell CA, Ball AR, Magiorkinis E, Chatzipanagiotou S, Hamblin MR, Hadjifrangiskou M, Tegos GP. Options and Limitations in Clinical Investigation of Bacterial Biofilms. Clin Microbiol Rev 2018; 31:e00084-16. [PMID: 29618576 PMCID: PMC6056845 DOI: 10.1128/cmr.00084-16] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria can form single- and multispecies biofilms exhibiting diverse features based upon the microbial composition of their community and microenvironment. The study of bacterial biofilm development has received great interest in the past 20 years and is motivated by the elegant complexity characteristic of these multicellular communities and their role in infectious diseases. Biofilms can thrive on virtually any surface and can be beneficial or detrimental based upon the community's interplay and the surface. Advances in the understanding of structural and functional variations and the roles that biofilms play in disease and host-pathogen interactions have been addressed through comprehensive literature searches. In this review article, a synopsis of the methodological landscape of biofilm analysis is provided, including an evaluation of the current trends in methodological research. We deem this worthwhile because a keyword-oriented bibliographical search reveals that less than 5% of the biofilm literature is devoted to methodology. In this report, we (i) summarize current methodologies for biofilm characterization, monitoring, and quantification; (ii) discuss advances in the discovery of effective imaging and sensing tools and modalities; (iii) provide an overview of tailored animal models that assess features of biofilm infections; and (iv) make recommendations defining the most appropriate methodological tools for clinical settings.
Collapse
Affiliation(s)
- Maria Magana
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
| | - Christina Sereti
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Microbiology, Thriassio General Hospital, Attiki, Greece
| | - Anastasios Ioannidis
- Department of Clinical Microbiology, Athens Medical School, Aeginition Hospital, Athens, Greece
- Department of Nursing, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Sparta, Greece
| | - Courtney A Mitchell
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Anthony R Ball
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
| | - Emmanouil Magiorkinis
- Department of Hygiene, Epidemiology and Medical Statistics, Medical School, University of Athens, Athens-Goudi, Greece
| | | | - Michael R Hamblin
- Harvard-MIT Division of Health Science and Technology, Cambridge, Massachusetts, USA
- Department of Dermatology, Harvard Medical School, Boston, Massachusetts, USA
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Maria Hadjifrangiskou
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - George P Tegos
- Gliese 623b, Mendon, Massachusetts, USA
- GAMA Therapeutics LLC, Pepperell, Massachusetts, USA
| |
Collapse
|
32
|
Rosenthal AF, Griffin JS, Wagner M, Packman AI, Balogun O, Wells GF. Morphological analysis of pore size and connectivity in a thick mixed-culture biofilm. Biotechnol Bioeng 2018; 115:2268-2279. [PMID: 29777596 DOI: 10.1002/bit.26729] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 05/07/2018] [Accepted: 05/16/2018] [Indexed: 11/07/2022]
Abstract
Morphological parameters are commonly used to predict transport and metabolic kinetics in biofilms. Yet, quantification of biofilm morphology remains challenging because of imaging technology limitations and lack of robust analytical approaches. We present a novel set of imaging and image analysis techniques to estimate internal porosity, pore size distributions, and pore network connectivity to a depth of 1 mm at a resolution of 10 µm in a biofilm exhibiting both heterotrophic and nitrifying activities. Optical coherence tomography (OCT) scans revealed an extensive pore network with diameters as large as 110 µm directly connected to the biofilm surface and surrounding fluid. Thin-section fluorescence in situ hybridization microscopy revealed that ammonia-oxidizing bacteria (AOB) distributed through the entire thickness of the biofilm. AOB were particularly concentrated in the biofilm around internal pores. Areal porosity values estimated from OCT scans were consistently lower than those estimated from multiphoton laser scanning microscopy, though the two imaging modalities showed a statistically significant correlation (r = 0.49, p < 0.0001). Estimates of areal porosity were moderately sensitive to gray-level threshold selection, though several automated thresholding algorithms yielded similar values to those obtained by manually thresholding performed by a panel of environmental engineering researchers (±25% relative error). These findings advance our ability to quantitatively describe the geometry of biofilm internal pore networks at length scales relevant to engineered biofilm reactors and suggest that internal pore structures provide crucial habitat for nitrifier growth.
Collapse
Affiliation(s)
- Alex F Rosenthal
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois
| | - James S Griffin
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois
| | - Michael Wagner
- Department of Water Chemistry and Water Technology, Engler-Bunte-Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Aaron I Packman
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois
| | - Oluwaseyi Balogun
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois
| | - George F Wells
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois
| |
Collapse
|
33
|
Carrel M, Morales VL, Beltran MA, Derlon N, Kaufmann R, Morgenroth E, Holzner M. Biofilms in 3D porous media: Delineating the influence of the pore network geometry, flow and mass transfer on biofilm development. WATER RESEARCH 2018; 134:280-291. [PMID: 29433078 DOI: 10.1016/j.watres.2018.01.059] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 01/24/2018] [Accepted: 01/25/2018] [Indexed: 06/08/2023]
Abstract
This study investigates the functional correspondence between porescale hydrodynamics, mass transfer, pore structure and biofilm morphology during progressive biofilm colonization of a porous medium. Hydrodynamics and the structure of both the porous medium and the biofilm are experimentally measured with 3D particle tracking velocimetry and micro X-ray Computed Tomography, respectively. The analysis focuses on data obtained in a clean porous medium after 36 h of biofilm growth. Registration of the particle tracking and X-ray data sets allows to delineate the interplay between porous medium geometry, hydrodynamic and mass transfer processes on the morphology of the developing biofilm. A local analysis revealed wide distributions of wall shear stresses and concentration boundary layer thicknesses. The spatial distribution of the biofilm patches uncovered that the wall shear stresses controlled the biofilm development. Neither external nor internal mass transfer limitations were noticeable in the considered system, consistent with the excess supply of nutrient and electron acceptors. The wall shear stress remained constant in the vicinity of the biofilm but increased substantially elsewhere.
Collapse
Affiliation(s)
- Maxence Carrel
- Institute of Environmental Engineering, ETH Zürich, Stefano-Franscini-Platz 5, 8093 Zürich, Switzerland
| | - Verónica L Morales
- Institute of Environmental Engineering, ETH Zürich, Stefano-Franscini-Platz 5, 8093 Zürich, Switzerland; Department of Civil and Environmental Engineering, University of California, Davis, CA, USA
| | - Mario A Beltran
- School of Science, RMIT, Melbourne, Australia; Empa, Swiss Federal Laboratories for Materials Science and Technology, Center for X-ray Analytics, Dübendorf, Switzerland
| | - Nicolas Derlon
- Institute of Environmental Engineering, ETH Zürich, Stefano-Franscini-Platz 5, 8093 Zürich, Switzerland; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Rolf Kaufmann
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Center for X-ray Analytics, Dübendorf, Switzerland
| | - Eberhard Morgenroth
- Institute of Environmental Engineering, ETH Zürich, Stefano-Franscini-Platz 5, 8093 Zürich, Switzerland; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Markus Holzner
- Institute of Environmental Engineering, ETH Zürich, Stefano-Franscini-Platz 5, 8093 Zürich, Switzerland.
| |
Collapse
|
34
|
Sønderholm M, Koren K, Wangpraseurt D, Jensen PØ, Kolpen M, Kragh KN, Bjarnsholt T, Kühl M. Tools for studying growth patterns and chemical dynamics of aggregated Pseudomonas aeruginosa exposed to different electron acceptors in an alginate bead model. NPJ Biofilms Microbiomes 2018; 4:3. [PMID: 29479470 PMCID: PMC5818519 DOI: 10.1038/s41522-018-0047-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 01/07/2018] [Accepted: 01/24/2018] [Indexed: 12/31/2022] Open
Abstract
In chronic infections, bacterial pathogens typically grow as small dense cell aggregates embedded in a matrix consisting of, e.g., wound bed sludge or lung mucus. Such biofilm growth mode exhibits extreme tolerance towards antibiotics and the immune defence system. The bacterial aggregates are exposed to physiological heterogeneity and O2 limitation due to steep chemical gradients through the matrix, which is are hypothesised to contribute to antibiotic tolerance. Using a novel combination of microsensor and bioimaging analysis, we investigated growth patterns and chemical dynamics of the pathogen Pseudomonas aeruginosa in an alginate bead model, which mimics growth in chronic infections better than traditional biofilm experiments in flow chambers. Growth patterns were strongly affected by electron acceptor availability and the presence of chemical gradients, where the combined presence of O2 and nitrate yielded highest bacterial growth by combined aerobic respiration and denitrification.
Collapse
Affiliation(s)
- Majken Sønderholm
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark
| | - Klaus Koren
- Marine Biology Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, DK-3000 Helsingør, Denmark
| | - Daniel Wangpraseurt
- Marine Biology Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, DK-3000 Helsingør, Denmark
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW UK
| | - Peter Østrup Jensen
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark
- Department of Clinical Microbiology 9301, Copenhagen University Hospital, Rigshospitalet, Juliane Maries Vej 22, Copenhagen, Denmark
| | - Mette Kolpen
- Department of Clinical Microbiology 9301, Copenhagen University Hospital, Rigshospitalet, Juliane Maries Vej 22, Copenhagen, Denmark
| | - Kasper Nørskov Kragh
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark
| | - Thomas Bjarnsholt
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark
- Department of Clinical Microbiology 9301, Copenhagen University Hospital, Rigshospitalet, Juliane Maries Vej 22, Copenhagen, Denmark
| | - Michael Kühl
- Marine Biology Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, DK-3000 Helsingør, Denmark
- Climate Change Cluster, University of Technology Sydney, Broadway, NSW 2007 Australia
| |
Collapse
|
35
|
Hou J, Veeregowda DH, van de Belt-Gritter B, Busscher HJ, van der Mei HC. Extracellular Polymeric Matrix Production and Relaxation under Fluid Shear and Mechanical Pressure in Staphylococcus aureus Biofilms. Appl Environ Microbiol 2018; 84:e01516-17. [PMID: 29054874 PMCID: PMC5734043 DOI: 10.1128/aem.01516-17] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 10/11/2017] [Indexed: 12/20/2022] Open
Abstract
The viscoelasticity of a biofilm's EPS (extracellular polymeric substance) matrix conveys protection against mechanical challenges, but adaptive responses of biofilm inhabitants to produce EPS are not well known. Here, we compare the responses of a biofilm of an EPS-producing (ATCC 12600) and a non-EPS producing (5298) Staphylococcus aureus strain to fluid shear and mechanical challenge. Confocal laser scanning microscopy confirmed absence of calcofluor-white-stainable EPS in biofilms of S. aureus 5298. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy combined with tribometry indicated that polysaccharide production per bacterium in the initial adhering layer was higher during growth at high shear than at low shear and that this increased EPS production extended to entire biofilms, as indicated by tribometrically measured coefficients of friction (CoF). CoF of biofilms grown under high fluid shear were higher than those when grown under low shear, likely due to wash-off polysaccharides. Measurement of a biofilm's CoF implies application of mechanical pressure that yielded an immediate increase in the polysaccharide band area of S. aureus ATCC 12600 biofilms due to their compression. Compression decreased after relief of pressure to the level observed prior to mechanical pressure. For biofilms grown under high shear, this coincided with a higher percent whiteness in optical coherence tomography-images indicative of water outflow, returning back into the biofilm during stress relaxation. Biofilms grown under low shear, however, were stimulated during tribometry to produce EPS, also after relief of stress. Knowledge of factors that govern EPS production and water flow in biofilms will allow better control of biofilms under mechanical challenge and better understanding of the barrier properties of biofilms against antimicrobial penetration.IMPORTANCE Adaptive responses of biofilm inhabitants in nature to environmental challenges such as fluid shear and mechanical pressure often involve EPS production with the aim of protecting biofilm inhabitants. EPS can assist biofilm bacteria in remaining attached or can impede antimicrobial penetration. The TriboChemist is a recently introduced instrument, allowing the study of initially adhering bacteria to a germanium crystal using ATR-FTIR spectroscopy, while simultaneously allowing measurement of the coefficient of friction of a biofilm, which serves as an indicator of the EPS content of a biofilm. EPS production can be stimulated by both fluid shear during growth and mechanical pressure, while increased EPS production can continue after pressure relaxation of the biofilm. Since EPS is pivotal in the protection of biofilm inhabitants against mechanical and chemical challenges, knowledge of the factors that make biofilm inhabitants decide to produce EPS, as provided in this study, is important for the development of biofilm control measures.
Collapse
Affiliation(s)
- Jiapeng Hou
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Groningen, The Netherlands
| | - Deepak H Veeregowda
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Groningen, The Netherlands
- Ducom Instruments Europe BV, Center for Innovation, Groningen, The Netherlands
| | - Betsy van de Belt-Gritter
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Groningen, The Netherlands
| | - Henk J Busscher
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Groningen, The Netherlands
| | - Henny C van der Mei
- University of Groningen and University Medical Center Groningen, Department of Biomedical Engineering, Groningen, The Netherlands
| |
Collapse
|
36
|
Gusnaniar N, Sjollema J, Nuryastuti T, Peterson BW, van de Belt-Gritter B, de Jong ED, van der Mei HC, Busscher HJ. Structural changes in S. epidermidis biofilms after transmission between stainless steel surfaces. BIOFOULING 2017; 33:712-721. [PMID: 28868925 DOI: 10.1080/08927014.2017.1360870] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 07/25/2017] [Indexed: 06/07/2023]
Abstract
Transmission is a main route for bacterial contamination, involving bacterial detachment from a donor and adhesion to receiver surfaces. This work aimed to compare transmission of an extracellular polymeric substance (EPS) producing and a non-EPS producing Staphylococcus epidermidis strain from biofilms on stainless steel. After transmission, donor surfaces remained fully covered with biofilm, indicating transmission through cohesive failure in the biofilm. Counter to the numbers of biofilm bacteria, the donor and receiver biofilm thicknesses did not add up to the pre-transmission donor biofilm thickness, suggesting more compact biofilms after transmission, especially for non-EPS producing staphylococci. Accordingly, staphylococcal density per unit biofilm volume had increased from 0.20 to 0.52 μm-3 for transmission of the non-EPS producing strain under high contact pressure. The EPS producing strain had similar densities before and after transmission (0.17 μm-3). This suggests three phases in biofilm transmission: (1) compression, (2) separation and (3) relaxation of biofilm structure to its pre-transmission density in EPS-rich biofilms.
Collapse
Affiliation(s)
- Niar Gusnaniar
- a Department of Biomedical Engineering , University of Groningen and University Medical Center Groningen , Groningen , the Netherlands
| | - Jelmer Sjollema
- a Department of Biomedical Engineering , University of Groningen and University Medical Center Groningen , Groningen , the Netherlands
| | - Titik Nuryastuti
- b Faculty of Medicine, Department of Microbiology , Universitas Gadjah Mada , Yogyakarta , Indonesia
| | - Brandon W Peterson
- a Department of Biomedical Engineering , University of Groningen and University Medical Center Groningen , Groningen , the Netherlands
| | - Betsy van de Belt-Gritter
- a Department of Biomedical Engineering , University of Groningen and University Medical Center Groningen , Groningen , the Netherlands
| | - Ed D de Jong
- a Department of Biomedical Engineering , University of Groningen and University Medical Center Groningen , Groningen , the Netherlands
| | - Henny C van der Mei
- a Department of Biomedical Engineering , University of Groningen and University Medical Center Groningen , Groningen , the Netherlands
| | - Henk J Busscher
- a Department of Biomedical Engineering , University of Groningen and University Medical Center Groningen , Groningen , the Netherlands
| |
Collapse
|
37
|
Fabbri S, Li J, Howlin RP, Rmaile A, Gottenbos B, De Jager M, Starke EM, Aspiras M, Ward MT, Cogan NG, Stoodley P. Fluid-driven interfacial instabilities and turbulence in bacterial biofilms. Environ Microbiol 2017; 19:4417-4431. [PMID: 28799690 DOI: 10.1111/1462-2920.13883] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 08/03/2017] [Indexed: 11/27/2022]
Abstract
Biofilms are thin layers of bacteria embedded within a slime matrix that live on surfaces. They are ubiquitous in nature and responsible for many medical and dental infections, industrial fouling and are also evident in ancient fossils. A biofilm structure is shaped by growth, detachment and response to mechanical forces acting on them. The main contribution to biofilm versatility in response to physical forces is the matrix that provides a platform for the bacteria to grow. The interaction between biofilm structure and hydrodynamics remains a fundamental question concerning biofilm dynamics. Here, we document the appearance of ripples and wrinkles in biofilms grown from three species of bacteria when subjected to high-velocity fluid flows. Linear stability analysis suggested that the ripples were Kelvin-Helmholtz Instabilities. The analysis also predicted a strong dependence of the instability formation on biofilm viscosity explaining the different surface corrugations observed. Turbulence through Kelvin-Helmholtz instabilities occurring at the interface demonstrated that the biofilm flows like a viscous liquid under high flow velocities applied within milliseconds. Biofilm fluid-like behavior may have important implications for our understanding of how fluid flow influences biofilm biology since turbulence will likely disrupt metabolite and signal gradients as well as community stratification.
Collapse
Affiliation(s)
- Stefania Fabbri
- National Centre for Advanced Tribology at Southampton (nCATS), Mechanical Engineering Department, University of Southampton, Southampton SO17 1BJ, UK
| | - Jian Li
- Department of Mathematics, Florida State University, Tallahassee, FL 32306, USA
| | - Robert P Howlin
- National Institute for Health Research Southampton Respiratory Biomedical Research Unit, Southampton Centre for Biomedical Research, University Hospital Southampton NHS Foundation Trust, Southampton SO17 1BJ, UK.,Centre for Biological Sciences, Faculty of Natural and Environmental Sciences and Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Amir Rmaile
- Philips Research, Eindhoven 5656, AE, The Netherlands
| | | | | | | | | | | | - Nicholas G Cogan
- Department of Mathematics, Florida State University, Tallahassee, FL 32306, USA
| | - Paul Stoodley
- National Centre for Advanced Tribology at Southampton (nCATS), Mechanical Engineering Department, University of Southampton, Southampton SO17 1BJ, UK.,Department of Microbial Infection and Immunity and the Department of Orthopaedics, Centre for Microbial Interface Biology, The Ohio State University, Columbus, OH, 43210, USA
| |
Collapse
|
38
|
Even C, Marlière C, Ghigo JM, Allain JM, Marcellan A, Raspaud E. Recent advances in studying single bacteria and biofilm mechanics. Adv Colloid Interface Sci 2017; 247:573-588. [PMID: 28754382 DOI: 10.1016/j.cis.2017.07.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/18/2017] [Accepted: 07/18/2017] [Indexed: 12/15/2022]
Abstract
Bacterial biofilms correspond to surface-associated bacterial communities embedded in hydrogel-like matrix, in which high cell density, reduced diffusion and physico-chemical heterogeneity play a protective role and induce novel behaviors. In this review, we present recent advances on the understanding of how bacterial mechanical properties, from single cell to high-cell density community, determine biofilm tri-dimensional growth and eventual dispersion and we attempt to draw a parallel between these properties and the mechanical properties of other well-studied hydrogels and living systems.
Collapse
|
39
|
Wang Y, Fortunato L, Jeong S, Leiknes T. Gravity-driven membrane system for secondary wastewater effluent treatment: Filtration performance and fouling characterization. Sep Purif Technol 2017. [DOI: 10.1016/j.seppur.2017.04.027] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
40
|
Carrel M, Beltran MA, Morales VL, Derlon N, Morgenroth E, Kaufmann R, Holzner M. Biofilm imaging in porous media by laboratory X-Ray tomography: Combining a non-destructive contrast agent with propagation-based phase-contrast imaging tools. PLoS One 2017; 12:e0180374. [PMID: 28732010 PMCID: PMC5521744 DOI: 10.1371/journal.pone.0180374] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 06/14/2017] [Indexed: 11/21/2022] Open
Abstract
X-ray tomography is a powerful tool giving access to the morphology of biofilms, in 3D porous media, at the mesoscale. Due to the high water content of biofilms, the attenuation coefficient of biofilms and water are very close, hindering the distinction between biofilms and water without the use of contrast agents. Until now, the use of contrast agents such as barium sulfate, silver-coated micro-particles or 1-chloronaphtalene added to the liquid phase allowed imaging the biofilm 3D morphology. However, these contrast agents are not passive and potentially interact with the biofilm when injected into the sample. Here, we use a natural inorganic compound, namely iron sulfate, as a contrast agent progressively bounded in dilute or colloidal form into the EPS matrix during biofilm growth. By combining a very long source-to-detector distance on a X-ray laboratory source with a Lorentzian filter implemented prior to tomographic reconstruction, we substantially increase the contrast between the biofilm and the surrounding liquid, which allows revealing the 3D biofilm morphology. A comparison of this new method with the method proposed by Davit et al (Davit et al., 2011), which uses barium sulfate as a contrast agent to mark the liquid phase was performed. Quantitative evaluations between the methods revealed substantial differences for the volumetric fractions obtained from both methods. Namely, contrast agent—biofilm interactions (e.g. biofilm detachment) occurring during barium sulfate injection caused a reduction of the biofilm volumetric fraction of more than 50% and displacement of biofilm patches elsewhere in the column. Two key advantages of the newly proposed method are that passive addition of iron sulfate maintains the integrity of the biofilm prior to imaging, and that the biofilm itself is marked by the contrast agent, rather than the liquid phase as in other available methods. The iron sulfate method presented can be applied to understand biofilm development and bioclogging mechanisms in porous materials and the obtained biofilm morphology could be an ideal basis for 3D numerical calculations of hydrodynamic conditions to investigate biofilm-flow coupling.
Collapse
Affiliation(s)
- Maxence Carrel
- Institute of Environmental Engineering, ETH Zürich, Stefano Franscini-Platz 5, 8093 Zurich, Switzerland
| | - Mario A. Beltran
- Swiss Federal Laboratories for Materials Science and Technology (EMPA), Dübendorf, Switzerland
| | - Verónica L. Morales
- Institute of Environmental Engineering, ETH Zürich, Stefano Franscini-Platz 5, 8093 Zurich, Switzerland
- Department of Civil and Environmental Engineering, University of California Davis, Davis, California, United States of America
| | - Nicolas Derlon
- Institute of Environmental Engineering, ETH Zürich, Stefano Franscini-Platz 5, 8093 Zurich, Switzerland
- Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Dübendorf, Switzerland
| | - Eberhard Morgenroth
- Institute of Environmental Engineering, ETH Zürich, Stefano Franscini-Platz 5, 8093 Zurich, Switzerland
- Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Dübendorf, Switzerland
| | - Rolf Kaufmann
- Swiss Federal Laboratories for Materials Science and Technology (EMPA), Dübendorf, Switzerland
| | - Markus Holzner
- Institute of Environmental Engineering, ETH Zürich, Stefano Franscini-Platz 5, 8093 Zurich, Switzerland
- * E-mail:
| |
Collapse
|
41
|
Wagner M, Horn H. Optical coherence tomography in biofilm research: A comprehensive review. Biotechnol Bioeng 2017; 114:1386-1402. [DOI: 10.1002/bit.26283] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/10/2017] [Accepted: 03/01/2017] [Indexed: 01/29/2023]
Affiliation(s)
- Michael Wagner
- Karlsruhe Institute of Technology; Engler-Bunte-Institut; Chair of Water Chemistry and Water Technology; Engler-Bunte-Ring 9 76131 Karlsruhe Germany
- Karlsruhe Institute of Technology; Institute of Functional Interfaces; Eggenstein-Leopoldshafen Germany
| | - Harald Horn
- Karlsruhe Institute of Technology; Engler-Bunte-Institut; Chair of Water Chemistry and Water Technology; Engler-Bunte-Ring 9 76131 Karlsruhe Germany
| |
Collapse
|
42
|
Wangpraseurt D, Wentzel C, Jacques SL, Wagner M, Kühl M. In vivo imaging of coral tissue and skeleton with optical coherence tomography. J R Soc Interface 2017; 14:20161003. [PMID: 28250104 PMCID: PMC5378135 DOI: 10.1098/rsif.2016.1003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 02/01/2017] [Indexed: 11/12/2022] Open
Abstract
Application of optical coherence tomography (OCT) for in vivo imaging of tissue and skeleton structure of intact living corals enabled the non-invasive visualization of coral tissue layers (endoderm versus ectoderm), skeletal cavities and special structures such as mesenterial filaments and mucus release from intact living corals. Coral host chromatophores containing green fluorescent protein-like pigment granules appeared hyper-reflective to near-infrared radiation allowing for excellent optical contrast in OCT and a rapid characterization of chromatophore size, distribution and abundance. In vivo tissue plasticity could be quantified by the linear contraction velocity of coral tissues upon illumination resulting in dynamic changes in the live coral tissue surface area, which varied by a factor of 2 between the contracted and expanded state of a coral. Our study provides a novel view on the in vivo organization of coral tissue and skeleton and highlights the importance of microstructural dynamics for coral ecophysiology.
Collapse
Affiliation(s)
- Daniel Wangpraseurt
- Marine Biological Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, Helsingør 3000, Denmark
| | - Camilla Wentzel
- Marine Biological Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, Helsingør 3000, Denmark
| | - Steven L Jacques
- Department of Biomedical Engineering, Oregon Health and Science University, 3303 SW Bond Avenue, Portland, OR 97239, USA
| | - Michael Wagner
- Engler-Bunte Institute, Chair of Water Chemistry and Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 1, 76131 Karlsruhe, Germany
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, Helsingør 3000, Denmark
- Climate Change Cluster, University of Technology Sydney, PO Box 123, Broadway, Sydney, New South Wales 2007, Australia
| |
Collapse
|
43
|
Qian J, Horn H, Tarchitzky J, Chen Y, Katz S, Wagner M. Water quality and daily temperature cycle affect biofilm formation in drip irrigation devices revealed by optical coherence tomography. BIOFOULING 2017; 33:211-221. [PMID: 28270050 DOI: 10.1080/08927014.2017.1285017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 01/14/2017] [Indexed: 06/06/2023]
Abstract
Drip irrigation is a water-saving technology. To date, little is known about how biofilm forms in drippers of irrigation systems. In this study, the internal dripper geometry was recreated in 3-D printed microfluidic devices (MFDs). To mimic the temperature conditions in (semi-) arid areas, experiments were conducted in a temperature controlled box between 20 and 50°C. MFDs were either fed with two different treated wastewater (TWW) or synthetic wastewater. Biofilm formation was monitored non-invasively and in situ by optical coherence tomography (OCT). 3-D OCT datasets reveal the major fouling position and illustrate that biofilm development was influenced by fluid dynamics. Biofilm volumetric coverage of the labyrinth up to 60% did not reduce the discharge rate, whereas a further increase to 80% reduced the discharge rate by 50%. Moreover, the biofilm formation rate was significantly inhibited in daily temperature cycle independent of the cultivation medium used.
Collapse
Affiliation(s)
- Jueying Qian
- a Water Chemistry and Water Technology , Engler-Bunte-Institut, Karlsruhe Institute of Technology , Karlsruhe , Germany
| | - Harald Horn
- a Water Chemistry and Water Technology , Engler-Bunte-Institut, Karlsruhe Institute of Technology , Karlsruhe , Germany
| | - Jorge Tarchitzky
- b The Robert H. Smith Faculty of Agriculture, Food and Environment , The Hebrew University of Jerusalem , Rehovot , Israel
| | - Yona Chen
- b The Robert H. Smith Faculty of Agriculture, Food and Environment , The Hebrew University of Jerusalem , Rehovot , Israel
| | - Sagi Katz
- b The Robert H. Smith Faculty of Agriculture, Food and Environment , The Hebrew University of Jerusalem , Rehovot , Israel
| | - Michael Wagner
- a Water Chemistry and Water Technology , Engler-Bunte-Institut, Karlsruhe Institute of Technology , Karlsruhe , Germany
- c Institute of Functional Interfaces , Karlsruhe Institute of Technology , Eggenstein-Leopoldshafen , Germany
| |
Collapse
|
44
|
Time-resolved monitoring of biofouling development on a flat sheet membrane using optical coherence tomography. Sci Rep 2017; 7:15. [PMID: 28148958 PMCID: PMC5428376 DOI: 10.1038/s41598-017-00051-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 12/19/2016] [Indexed: 11/09/2022] Open
Abstract
Biofouling on a membrane leads to significant performance decrease in filtration processes. In this study, an optical coherence tomography (OCT) was used to perform a time-resolved analysis of dynamic biofouling development on a submerged membrane under continuous operation. A real-time change in the biofouling morphology was calculated through the image analysis of OCT scans. Three videos were generated through the acquisition of serial static images. This is the first study that displays the dynamic biofouling formation process as a video. The acquisition of OCT cross-sectional scans of the biofouling allowed to evaluate the time-lapsed evolution for three different time periods (early stage, double layers and long-term). Firstly, at the early filtration stage, membrane coverage and average biofouling layer thickness were found to be linearly correlated with the permeate flux pattern. Secondly, after 3 d of operation, an anomalous morphology was observed, constituted by a double-layered biofouling structure: denser on the bottom and looser on the top. In a long-term operation, the biofouling structure underwent a dynamic evolution over time, resulting in a multi-layered structure. The biofouling formation information was closely associated with filtration performance (i.e. flux) indicating the suitability of OCT as real-time and in-situ biofouling monitoring technique.
Collapse
|
45
|
Fortunato L, Bucs S, Linares RV, Cali C, Vrouwenvelder JS, Leiknes T. Spatially-resolved in-situ quantification of biofouling using optical coherence tomography (OCT) and 3D image analysis in a spacer filled channel. J Memb Sci 2017. [DOI: 10.1016/j.memsci.2016.11.052] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
46
|
Antibacterial and anti-biofilm efficacy of fluoropolymer coating by a 2,3,5,6-tetrafluoro-p-phenylenedimethanol structure. Colloids Surf B Biointerfaces 2016; 151:363-371. [PMID: 28056438 DOI: 10.1016/j.colsurfb.2016.12.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 12/10/2016] [Accepted: 12/14/2016] [Indexed: 11/20/2022]
Abstract
Fluorinated polymers generally function as antibacterial agents, but their anti-biofilm effect remains unresolved. This study investigates the efficacy of fluoropolymers containing 2,3,5,6-tetrafluoro-p-phenylenedimethanol (TFPDM) in preventing biofilm formation by Bacillus subtilis and Escherichia coli (Gram-positive and Gram-negative bacterial species). To this end, TFPDM-based acrylate and epoxy polymers (AF and EF, respectively) and their structural analogues without TFPDM (A and E, respectively) were synthesized. All polymers were coated onto polyethylene terephthalate (PET) sheets. Relative to pristine PET, sheets coated with AF reduced the initial bacterial adhesion (72h) and biofilm formation (30days) of B. subtilis by 27.6% and 68.7% and of E. coli by 89.2% and 93.8%, respectively. The comparable antibacterial and anti-biofilm efficacies were obtained by sheets with EF. The biofilm detachment was substantially facilitated from the AF, compared with the structural analogue without TFPDM (A). In this comprehensive study, the bacterial adhesion and subsequent biofilm formation were prevented by TFPDM-containing polymers effectively.
Collapse
|
47
|
Biofilms 2015: Multidisciplinary Approaches Shed Light into Microbial Life on Surfaces. J Bacteriol 2016; 198:2553-63. [PMID: 26977109 DOI: 10.1128/jb.00156-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The 7th ASM Conference on Biofilms was held in Chicago, Illinois, from 24 to 29 October 2015. The conference provided an international forum for biofilm researchers across academic and industry platforms, and from different scientific disciplines, to present and discuss new findings and ideas. The meeting covered a wide range of topics, spanning environmental sciences, applied biology, evolution, ecology, physiology, and molecular biology of the biofilm lifestyle. This report summarizes the presentations with regard to emerging biofilm-related themes.
Collapse
|
48
|
Weiss N, Obied KETE, Kalkman J, Lammertink RG, van Leeuwen TG. Measurement of biofilm growth and local hydrodynamics using optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2016; 7:3508-3518. [PMID: 27699116 PMCID: PMC5030028 DOI: 10.1364/boe.7.003508] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 07/16/2016] [Accepted: 07/29/2016] [Indexed: 05/08/2023]
Abstract
We report on localized and simultaneous measurement of biofilm growth and local hydrodynamics in a microfluidic channel using optical coherence tomography. We measure independently with high spatio-temporal resolution the longitudinal flow velocity component parallel to the imaging beam and the transverse flow velocity component perpendicular to the imaging beam. Based on the measured velocities we calculate the shear-rates in the flow channel. We show the relation between the measured biofilm structure and flow velocities as biofilm growth progresses over the course of 48 hours.
Collapse
Affiliation(s)
- Nicolás Weiss
- Biomedical Engineering & Physics, Academic Medical Center, University of Amsterdam, PO Box 22700, 1100 DE Amsterdam,
The Netherlands
| | - Khalid El Tayeb El Obied
- Soft Matter, Fluidics and Interfaces, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede,
The Netherlands
| | - Jeroen Kalkman
- Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft,
The Netherlands
| | - Rob G.H. Lammertink
- Soft Matter, Fluidics and Interfaces, MESA+ Institute for Nanotechnology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede,
The Netherlands
| | - Ton G. van Leeuwen
- Biomedical Engineering & Physics, Academic Medical Center, University of Amsterdam, PO Box 22700, 1100 DE Amsterdam,
The Netherlands
| |
Collapse
|
49
|
Larimer C, Suter JD, Bonheyo G, Addleman RS. In situ non-destructive measurement of biofilm thickness and topology in an interferometric optical microscope. JOURNAL OF BIOPHOTONICS 2016; 9:656-666. [PMID: 26992071 DOI: 10.1002/jbio.201500212] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 01/27/2016] [Accepted: 02/21/2016] [Indexed: 06/05/2023]
Abstract
Biofilms are ubiquitous and impact the environment, human health, dental hygiene, and a wide range of industrial processes. Biofilms are difficult to characterize when fully hydrated, especially in a non-destructive manner, because of their soft structure and water-like bulk properties. Herein a method of measuring and monitoring the thickness and topology of live biofilms of using white light interferometry is described. Using this technique, surface morphology, surface roughness, and biofilm thickness were measured over time without while the biofilm continued to grow. The thickness and surface topology of a P. putida biofilm were monitored growing from initial colonization to a mature biofilm. Measured thickness followed expected trends for bacterial growth. Surface roughness also increased over time and was a leading indicator of biofilm growth.
Collapse
Affiliation(s)
- Curtis Larimer
- Pacific Northwest National Laboratory, Battelle for the USDOE, PO Box 999, MSIN P7-50, Richland, WA, 99354, USA
| | - Jonathan D Suter
- Pacific Northwest National Laboratory, Battelle for the USDOE, PO Box 999, MSIN P7-50, Richland, WA, 99354, USA
| | - George Bonheyo
- Pacific Northwest National Laboratory, Battelle for the USDOE, PO Box 999, MSIN P7-50, Richland, WA, 99354, USA
| | - Raymond Shane Addleman
- Pacific Northwest National Laboratory, Battelle for the USDOE, PO Box 999, MSIN P7-50, Richland, WA, 99354, USA.
| |
Collapse
|
50
|
Shen Y, Huang C, Monroy GL, Janjaroen D, Derlon N, Lin J, Espinosa-Marzal R, Morgenroth E, Boppart SA, Ashbolt NJ, Liu WT, Nguyen TH. Response of Simulated Drinking Water Biofilm Mechanical and Structural Properties to Long-Term Disinfectant Exposure. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:1779-87. [PMID: 26756120 PMCID: PMC5135099 DOI: 10.1021/acs.est.5b04653] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Mechanical and structural properties of biofilms influence the accumulation and release of pathogens in drinking water distribution systems (DWDS). Thus, understanding how long-term residual disinfectants exposure affects biofilm mechanical and structural properties is a necessary aspect for pathogen risk assessment and control. In this study, elastic modulus and structure of groundwater biofilms was monitored by atomic force microscopy (AFM) and optical coherence tomography (OCT) during three months of exposure to monochloramine or free chlorine. After the first month of disinfectant exposure, the mean stiffness of monochloramine- or free-chlorine-treated biofilms was 4 to 9 times higher than those before treatment. Meanwhile, the biofilm thickness decreased from 120 ± 8 μm to 93 ± 6-107 ± 11 μm. The increased surface stiffness and decreased biofilm thickness within the first month of disinfectant exposure was presumably due to the consumption of biomass. However, by the second to third month during disinfectant exposure, the biofilm mean stiffness showed a 2- to 4-fold decrease, and the biofilm thickness increased to 110 ± 7-129 ± 8 μm, suggesting that the biofilms adapted to disinfectant exposure. After three months of the disinfectant exposure process, the disinfected biofilms showed 2-5 times higher mean stiffness (as determined by AFM) and 6-13-fold higher ratios of protein over polysaccharide, as determined by differential staining and confocal laser scanning microscopy (CLSM), than the nondisinfected groundwater biofilms. However, the disinfected biofilms and nondisinfected biofilms showed statistically similar thicknesses (t test, p > 0.05), suggesting that long-term disinfection may not significantly remove net biomass. This study showed how biofilm mechanical and structural properties vary in response to a complex DWDS environment, which will contribute to further research on the risk assessment and control of biofilm-associated-pathogens in DWDS.
Collapse
Affiliation(s)
| | | | | | | | - Nicolas Derlon
- Eawag: Swiss Federal Institute of Aquatic Science and Technology , 8600 Dübendorf, Switzerland
| | | | | | - Eberhard Morgenroth
- Eawag: Swiss Federal Institute of Aquatic Science and Technology , 8600 Dübendorf, Switzerland
- Institute of Environmental Engineering, ETH Zürich , 8093 Zürich, Switzerland
| | | | - Nicholas J Ashbolt
- School of Public Health, University of Alberta , Edmonton, AB T6G 2G7 Canada
| | | | | |
Collapse
|