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Samadi A, Kermanshahi Pour A, Gagnon G. Biodegradation of 1,4-dioxane in a continuous-flow bioelectrochemical reactor by biofilm of Pseudonocardia dioxanivorans CB1190 and microbial community on conductive carriers. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 337:122572. [PMID: 37717901 DOI: 10.1016/j.envpol.2023.122572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 08/14/2023] [Accepted: 09/15/2023] [Indexed: 09/19/2023]
Abstract
Bioelectrochemical degradation is an environmentally friendly, cost-effective and controllable way of providing electron acceptor to the microorganisms. A two-chamber continuous-flow bioelectrochemical reactor (BER) was developed in this study. The objective was to investigate the potential for enhancing the bioelectrochemical degradation of 1,4-dioxane (DX) by Pseudonocardia dioxanivorans CB1190 (CB1190) and microbial community biofilm on conductive and non-conductive carriers in low potentials (1.0-1.2 V) and currents (<2 mA). In the case of CB1190, biodegradation experiments at 1.0 V did not result in any observable change in DX removal efficiency (32.63 ± 2.48%) compared to the 0.0 V (31.69 ± 2.33%). However, the removal efficiency was much higher at 1.2 V (59.08 ± 0.86%). The higher removal at 1.2 V was attributed to an increase in dissolved oxygen (DO) concentration from 3.77 ± 0.33 mg/L at 0.0 V to 5.40 ± 0.11 mg/L at 1.2 V, which resulted from water electrolysis. In the case of microbial community, on the other hand, DX removal efficiency increased at 1.0 V (30.98 ± 1.10%) compared to 0.0 V (23.40 ± 1.02%) that can be attributed to a simultaneous increase in microbial activity from 2389 ± 118.5 ngATP/mgVSS at 0.0 V to 2942 ± 109 ngATP/mgVSS at 1.0 V. Analysis of the changes in microbial composition indicated enrichment of Alistipes and Lutispora at 1.0 V due to the ability of these genera to directly transfer electrons with conductive surface. On the other hand, no change was observed in the microbial community in the case of non-conductive carriers. Results of this study showed that electro-assisted biodegradation of DX at low potentials is possible through two different mechanisms (oxygen production and direct electron transfer with electrode) which makes this technique flexible and cost-effective. The novelty of this work lies in exploring the use of electrical assistance to enhance the biodegradation of DX in the presence of CB1190 and the microbial community. This study more specifically investigated lower potential than required water electrolysis potential, allowing microorganisms to be stimulated through mechanisms unrelated to oxygen generation.
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Affiliation(s)
- Aryan Samadi
- Biorefining and Remediation Laboratory, Department of Process Engineering and Applied Science, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Azadeh Kermanshahi Pour
- Biorefining and Remediation Laboratory, Department of Process Engineering and Applied Science, Dalhousie University, Halifax, Nova Scotia, Canada.
| | - Graham Gagnon
- Centre for Water Resources Studies, Department of Civil & Resource Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
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Xiong Y, Mason OU, Lowe A, Zhang Z, Zhou C, Chen G, Villalonga MJ, Tang Y. Investigating promising substrates for promoting 1,4-dioxane biodegradation: effects of ethane and tetrahydrofuran on microbial consortia. Biodegradation 2020; 31:171-182. [PMID: 32361902 DOI: 10.1007/s10532-020-09901-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 04/16/2020] [Indexed: 12/12/2022]
Abstract
Cometabolic biodegradation of 1,4-dioxane (dioxane) in the presence of primary substrates is a promising strategy for treating dioxane at environmentally relevant concentrations. Seven aqueous amendments (i.e., tetrahydrofuran (THF), butanone, acetone, 1-butanol, 2-butanol, phenol and acetate) and five gaseous amendments (i.e., C1-C4 alkanes and ethylene) were evaluated as the primary substrates for dioxane degradation by mixed microbial consortia. The aqueous amendments were tested in microcosm bottles and the gaseous amendments were tested in a continuous-flow membrane biofilm reactor with hollow fibers pressurized by the gaseous amendments. Ethane was found to be the most effective gaseous substrate and THF was the only aqueous substrate that promoted dioxane degradation. A diverse microbial community consisting of several putative dioxane degraders-Mycobacterium, Flavobacterium and Bradyrhizobiaceae-were enriched in the presence of ethane. This is the first study showing that ethane was the most effective substrate among the short-chain alkanes and it promoted dioxane degradation by enriching dioxane-degraders that did not harbor the well-known dioxane/tetrahydrofuran monooxygenase.
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Affiliation(s)
- Yi Xiong
- Department of Civil and Environmental Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL, 32310, USA
| | - Olivia U Mason
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Ashlee Lowe
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Zhiming Zhang
- Department of Civil and Environmental Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL, 32310, USA
| | - Chao Zhou
- Geosyntec Consultants Inc., Huntington Beach, CA, 92648, USA
| | - Gang Chen
- Department of Civil and Environmental Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL, 32310, USA
| | - Michael J Villalonga
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Youneng Tang
- Department of Civil and Environmental Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, FL, 32310, USA.
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