Continuous shear stress alters metabolism, mass-transport, and growth in electroactive biofilms independent of surface substrate transport
Electroactive bacteria such as Geobacter sulfurreducens and Shewanella onedensis produce electrical current during their respiration; this has been exploited in bioelectrochemical systems. These bacteria form thicker biofilms and stay more active than soluble-respiring bacteria biofilms because thei...
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| Format: | Article |
| Language: | English |
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Springer Nature
2020
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| Online Access: | https://hdl.handle.net/1721.1/127689 |
| _version_ | 1826207865378963456 |
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| author | Jones, A-Andrew D. Buie, Cullen |
| author2 | Massachusetts Institute of Technology. Department of Mechanical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Mechanical Engineering Jones, A-Andrew D. Buie, Cullen |
| author_sort | Jones, A-Andrew D. |
| collection | MIT |
| description | Electroactive bacteria such as Geobacter sulfurreducens and Shewanella onedensis produce electrical current during their respiration; this has been exploited in bioelectrochemical systems. These bacteria form thicker biofilms and stay more active than soluble-respiring bacteria biofilms because their electron acceptor is always accessible. In bioelectrochemical systems such as microbial fuel cells, corrosion-resistant metals uptake current from the bacteria, producing power. While beneficial for engineering applications, collecting current using corrosion resistant metals induces pH stress in the biofilm, unlike the naturally occurring process where a reduced metal combines with protons released during respiration. To reduce pH stress, some bioelectrochemical systems use forced convection to enhance mass transport of both nutrients and byproducts; however, biofilms’ small pore size limits convective transport, thus, reducing pH stress in these systems remains a challenge. Understanding how convection is necessary but not sufficient for maintaining biofilm health requires decoupling mass transport from momentum transport (i.e. fluidic shear stress). In this study we use a rotating disc electrode to emulate a practical bioelectrochemical system, while decoupling mass transport from shear stress. This is the first study to isolate the metabolic and structural changes in electroactive biofilms due to shear stress. We find that increased shear stress reduces biofilm development time while increasing its metabolic rate. Furthermore, we find biofilm health is negatively affected by higher metabolic rates over long-term growth due to the biofilm’s memory of the fluid flow conditions during the initial biofilm development phases. These results not only provide guidelines for improving performance of bioelectrochemical systems, but also reveal features of biofilm behavior. Results of this study suggest that optimized reactors may initiate operation at high shear to decrease development time before decreasing shear for steady-state operation. Furthermore, this biofilm memory discovered will help explain the presence of channels within biofilms observed in other studies. ©2019, The Author(s). |
| first_indexed | 2024-09-23T13:56:10Z |
| format | Article |
| id | mit-1721.1/127689 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T13:56:10Z |
| publishDate | 2020 |
| publisher | Springer Nature |
| record_format | dspace |
| spelling | mit-1721.1/1276892022-09-28T17:12:43Z Continuous shear stress alters metabolism, mass-transport, and growth in electroactive biofilms independent of surface substrate transport Jones, A-Andrew D. Buie, Cullen Massachusetts Institute of Technology. Department of Mechanical Engineering Electroactive bacteria such as Geobacter sulfurreducens and Shewanella onedensis produce electrical current during their respiration; this has been exploited in bioelectrochemical systems. These bacteria form thicker biofilms and stay more active than soluble-respiring bacteria biofilms because their electron acceptor is always accessible. In bioelectrochemical systems such as microbial fuel cells, corrosion-resistant metals uptake current from the bacteria, producing power. While beneficial for engineering applications, collecting current using corrosion resistant metals induces pH stress in the biofilm, unlike the naturally occurring process where a reduced metal combines with protons released during respiration. To reduce pH stress, some bioelectrochemical systems use forced convection to enhance mass transport of both nutrients and byproducts; however, biofilms’ small pore size limits convective transport, thus, reducing pH stress in these systems remains a challenge. Understanding how convection is necessary but not sufficient for maintaining biofilm health requires decoupling mass transport from momentum transport (i.e. fluidic shear stress). In this study we use a rotating disc electrode to emulate a practical bioelectrochemical system, while decoupling mass transport from shear stress. This is the first study to isolate the metabolic and structural changes in electroactive biofilms due to shear stress. We find that increased shear stress reduces biofilm development time while increasing its metabolic rate. Furthermore, we find biofilm health is negatively affected by higher metabolic rates over long-term growth due to the biofilm’s memory of the fluid flow conditions during the initial biofilm development phases. These results not only provide guidelines for improving performance of bioelectrochemical systems, but also reveal features of biofilm behavior. Results of this study suggest that optimized reactors may initiate operation at high shear to decrease development time before decreasing shear for steady-state operation. Furthermore, this biofilm memory discovered will help explain the presence of channels within biofilms observed in other studies. ©2019, The Author(s). 2020-09-24T14:42:11Z 2020-09-24T14:42:11Z 2019-02 2018-08 2019-07-19T16:41:17Z Article http://purl.org/eprint/type/JournalArticle 2045-2322 https://hdl.handle.net/1721.1/127689 Jones, A-Andrew D. and Cullen R. Buie, "Continuous shear stress alters metabolism, mass-transport, and growth in electroactive biofilms independent of surface substrate transport." Scientific Reports 9, 1 (February 2019): 2602 doi. 10.1038/s41598-019-39267-2 ©2019 Authors en https://dx.doi.org/10.1038/S41598-019-39267-2 Scientific Reports Creative Commons Attribution 4.0 International license https://creativecommons.org/licenses/by/4.0/ application/pdf Springer Nature Scientific Reports |
| spellingShingle | Jones, A-Andrew D. Buie, Cullen Continuous shear stress alters metabolism, mass-transport, and growth in electroactive biofilms independent of surface substrate transport |
| title | Continuous shear stress alters metabolism, mass-transport, and growth in electroactive biofilms independent of surface substrate transport |
| title_full | Continuous shear stress alters metabolism, mass-transport, and growth in electroactive biofilms independent of surface substrate transport |
| title_fullStr | Continuous shear stress alters metabolism, mass-transport, and growth in electroactive biofilms independent of surface substrate transport |
| title_full_unstemmed | Continuous shear stress alters metabolism, mass-transport, and growth in electroactive biofilms independent of surface substrate transport |
| title_short | Continuous shear stress alters metabolism, mass-transport, and growth in electroactive biofilms independent of surface substrate transport |
| title_sort | continuous shear stress alters metabolism mass transport and growth in electroactive biofilms independent of surface substrate transport |
| url | https://hdl.handle.net/1721.1/127689 |
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