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Zhao B, Zhang Z, Feng K, Peng X, Wang D, Cai W, Liu W, Wang A, Deng Y. Inoculum source determines the stress resistance of electroactive functional taxa in biofilms: A metagenomic perspective. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 945:174018. [PMID: 38906302 DOI: 10.1016/j.scitotenv.2024.174018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 05/20/2024] [Accepted: 06/13/2024] [Indexed: 06/23/2024]
Abstract
The inoculum has a crucial impact on bioreactor initialization and performance. However, there is currently a lack of guidance on selecting appropriate inocula for applications in environmental biotechnology. In this study, we applied microbial electrolysis cells (MECs) as models to investigate the differences in the functional potential of electroactive microorganisms (EAMs) within anodic biofilms developed from four different inocula (natural or artificial), using shotgun metagenomic techniques. We specifically focused on extracellular electron transfer (EET) function and stress resistance, which affect the performance and stability of MECs. Community profiling revealed that the family Geobacteraceae was the key EAM taxon in all biofilms, with Geobacter as the dominant genus. The c-type cytochrome gene imcH showed universal importance for Geobacteraceae EET and was utilized as a marker gene to evaluate the EET potential of EAMs. Additionally, stress response functional genes were used to assess the stress resistance potential of Geobacter species. Comparative analysis of imcH gene abundance revealed that EAMs with comparable overall EET potential could be enriched from artificial and natural inocula (P > 0.05). However, quantification of stress response gene copy numbers in the genomes demonstrated that EAMs originating from natural inocula possessed superior stress resistance potential (196 vs. 163). Overall, this study provides novel perspectives on the inoculum effect in bioreactors and offers theoretical guidance for selecting inoculum in environmental engineering applications.
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Affiliation(s)
- Bo Zhao
- CAS Key Laboratory for Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences (CAS), Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Zhaojing Zhang
- Institute of Marine Science and Technology, Shandong University, Qingdao 266237, China
| | - Kai Feng
- CAS Key Laboratory for Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences (CAS), Beijing 100085, China
| | - Xi Peng
- CAS Key Laboratory for Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences (CAS), Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Danrui Wang
- CAS Key Laboratory for Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences (CAS), Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Weiwei Cai
- School of Civil Engineering, Beijing Jiaotong University, Beijing, China
| | - Wenzong Liu
- State Key Lab of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China
| | - Aijie Wang
- CAS Key Laboratory for Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences (CAS), Beijing 100085, China; State Key Lab of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China
| | - Ye Deng
- CAS Key Laboratory for Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences (CAS), Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China.
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Li C, Lü F, Peng W, He PJ, Zhang H. Functional Redundant Microbiome Enhanced Anaerobic Digestion Efficiency under Ammonium Inhibition Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:6659-6669. [PMID: 38557040 DOI: 10.1021/acs.est.4c01227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Revealing the role of functional redundancy is of great importance considering its key role in maintaining the stability of microbial ecosystems in response to various disturbances. However, experimental evidence on this point is still lacking due to the difficulty in "manipulating" and depicting the degree of redundancy. In this study, manipulative experiments of functional redundancy were conducted by adopting the mixed inoculation strategy to evaluate its role in engineered anaerobic digestion systems under ammonium inhibition conditions. The results indicated that the functional redundancy gradient was successfully constructed and confirmed by evidence from pathway levels. All mixed inoculation groups exhibited higher methane production regardless of the ammonium level, indicating that functional redundancy is crucial in maintaining the system's efficiency. Further analysis of the metagenome-assembled genomes within different functional guilds revealed that the extent of redundancy decreased along the direction of the anaerobic digestion flow, and the role of functional redundancy appeared to be related to the stress level. The study also found that microbial diversity of key functional populations might play a more important role than their abundance on the system's performance under stress. The findings provide direct evidence and highlight the critical role of functional redundancy in enhancing the efficiency and stability of anaerobic digestion.
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Affiliation(s)
- Chao Li
- Institute of Waste Treatment & Reclamation, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Fan Lü
- Institute of Waste Treatment & Reclamation, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Wei Peng
- Institute of Waste Treatment & Reclamation, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Pin-Jing He
- Institute of Waste Treatment & Reclamation, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Hua Zhang
- Institute of Waste Treatment & Reclamation, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
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Christiaens AS, Van Steenkiste M, Rummens K, Smets I. Amyloid adhesin production in activated sludge is enhanced in lab-scale sequencing batch reactors: Feeding regime impacts microbial community and amyloid distribution. WATER RESEARCH X 2022; 17:100162. [PMID: 36479239 PMCID: PMC9720597 DOI: 10.1016/j.wroa.2022.100162] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Amyloid adhesins are β-sheet-rich extracellular proteins thought to contribute to bioflocculation. They are present in activated sludge to varying extent. However, it remains unclear which operational conditions promote their production. To this end, the abundance and distribution of amyloids and their potential producers were monitored in two lab-scale reactors operated in sequencing batch mode with an unaerated and aerated reaction phase. Various feeding regimes ranging from feast-famine to nearly continuous feeding were applied. Thioflavin T staining revealed more amyloids in the lab-scale reactors during all operational stages compared to the full-scale industrial and municipal inocula. Furthermore, the feeding regime impacted the distribution of produced amyloids from dense clusters during feast-famine conditions towards a dispersed distribution during nearly continuous feeding. This dispersed presence did not negatively impact the bioflocculation (towards average floc size and shear sensitivity). 16S rRNA sequencing detected several known EPS and amyloid producers. More continuous and, hence, partially aerobic feeding promoted the relative abundance of denitrifiers. Sequential Thioflavin T staining and fluorescence in situ hybridization identified Zoogloea and Ca. Competibacter as potential amyloid producers under the applied conditions. This experiment confirms that amyloid producers need to be triggered for production and that the feeding regime impacts the microbial community composition, which in turn influences the amyloid production and distribution.
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Steinberg LM, Martino AJ, House CH. Convergent Microbial Community Formation in Replicate Anaerobic Reactors Inoculated from Different Sources and Treating Ersatz Crew Waste. Life (Basel) 2021; 11:life11121374. [PMID: 34947905 PMCID: PMC8706314 DOI: 10.3390/life11121374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/25/2021] [Accepted: 12/02/2021] [Indexed: 11/16/2022] Open
Abstract
Future manned space travel will require efficient recycling of nutrients from organic waste back into food production. Microbial systems are a low-energy, efficient means of nutrient recycling, but their use in a life support system requires predictability and reproducibility in community formation and reactor performance. To assess the reproducibility of microbial community formation in fixed-film reactors, we inoculated replicate anaerobic reactors from two methanogenic inocula: a lab-scale fixed-film, plug-flow anaerobic reactor and an acidic transitional fen. Reactors were operated under identical conditions, and we assessed reactor performance and used 16s rDNA amplicon sequencing to determine microbial community formation. Reactor microbial communities were dominated by similar groups, but differences in community membership persisted in reactors inoculated from different sources. Reactor performance overlapped, suggesting a convergence of both reactor communities and organic matter mineralization. The results of this study suggest an optimized microbial community could be preserved and used to start new, or restart failed, anaerobic reactors in a life support system with predictable reactor performance.
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Affiliation(s)
| | - Amanda J. Martino
- Biology Department, School of STEAM, Saint Francis University, Loretto, PA 15940, USA;
| | - Christopher H. House
- Department of Geosciences, Earth and Environmental Systems Institute, College of Earth and Mineral Sciences, The Pennsylvania State University, University Park, State College, PA 16802, USA
- Correspondence: (L.M.S.); (C.H.H.)
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Lerner H, Öztürk B, Dohrmann AB, Thomas J, Marchal K, De Mot R, Dehaen W, Tebbe CC, Springael D. Culture-Independent Analysis of Linuron-Mineralizing Microbiota and Functions in on-Farm Biopurification Systems via DNA-Stable Isotope Probing: Comparison with Enrichment Culture. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:9387-9397. [PMID: 32569463 DOI: 10.1021/acs.est.0c02124] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Our understanding of the microorganisms involved in in situ biodegradation of xenobiotics, like pesticides, in natural and engineered environments is poor. On-farm biopurification systems (BPSs) treat farm-produced pesticide-contaminated wastewater to reduce surface water pollution. BPSs are a labor and cost-efficient technology but are still mainly operated as black box systems. We used DNA-stable isotope probing (DNA-SIP) and classical enrichment to be informed about the organisms responsible for in situ degradation of the phenylurea herbicide linuron in a BPS matrix. DNA-SIP identified Ramlibacter, Variovorax, and an unknown Comamonadaceae genus as the dominant linuron assimilators. While linuron-degrading Variovorax strains have been isolated repeatedly, Ramlibacter has never been associated before with linuron degradation. Genes and mobile genetic elements (MGEs) previously linked to linuron catabolism were enriched in the heavy DNA-SIP fractions, suggesting their involvement in in situ linuron assimilation. BPS material free cultivation of linuron degraders from the same BPS matrix resulted in a community dominated by Variovorax, while Ramlibacter was not observed. Our study provides evidence for the role of Variovorax in in situ linuron biodegradation in a BPS, alongside other organisms like Ramlibacter, and further shows that cultivation results in a biased representation of the in situ linuron-assimilating bacterial populations.
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Affiliation(s)
- Harry Lerner
- Division of Soil and Water Management, KU Leuven, B-3001 Heverlee-Leuven, Belgium
| | - Başak Öztürk
- Division of Soil and Water Management, KU Leuven, B-3001 Heverlee-Leuven, Belgium
| | - Anja B Dohrmann
- Thünen Institut für Biodiversität, 38116 Braunschweig, Germany
| | - Joice Thomas
- Molecular Design and Synthesis, KU Leuven, B-3001 Heverlee-Leuven, Belgium
| | - Kathleen Marchal
- Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9000 Gent, Belgium
| | - René De Mot
- Centre of Microbial and Plant Genetics, KU Leuven, B-3001 Heverlee-Leuven, Belgium
| | - Wim Dehaen
- Molecular Design and Synthesis, KU Leuven, B-3001 Heverlee-Leuven, Belgium
| | | | - Dirk Springael
- Division of Soil and Water Management, KU Leuven, B-3001 Heverlee-Leuven, Belgium
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