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Jin Y, Lu Y. Syntrophic Propionate Oxidation: One of the Rate-Limiting Steps of Organic Matter Decomposition in Anoxic Environments. Appl Environ Microbiol 2023; 89:e0038423. [PMID: 37097179 PMCID: PMC10231205 DOI: 10.1128/aem.00384-23] [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] [Indexed: 04/26/2023] Open
Abstract
Syntrophic propionate oxidation is one of the rate-limiting steps during anaerobic decomposition of organic matter in anoxic environments. Syntrophic propionate-oxidizing bacteria (SPOB) are members of the "rare biosphere" living at the edge of the thermodynamic limit in most natural habitats. Hitherto, only 10 bacterial species capable of syntrophic propionate oxidization have been identified. SPOB employ different metabolisms for propionate oxidation (e.g., methylmalonyl-CoA pathway and C6 dismutation pathway) and show diverse life strategies (e.g., obligately and facultatively syntrophic lifestyle). The flavin-based electron bifurcation/confurcation (FBEB/C) systems have been proposed to help solve the thermodynamic dilemma during the formation of the low-potential products H2 and formate. Molecular ecological approaches, such as DNA stable isotope probing (DNA-SIP) and metagenomics, have been used to detect SPOB in natural environments. Furthermore, the biogeographical pattern of SPOB has been recently described in paddy soils. A comprehensive understanding of SPOB is essential for better predicting and managing organic matter decomposition and carbon cycling in anoxic environments. In this review, we described the critical role of syntrophic propionate oxidation in anaerobic decomposition of organic matter, phylogenetic and metabolic diversity, life strategies and ecophysiology, composition of syntrophic partners, and pattern of biogeographic distribution of SPOB in natural environments. We ended up with a few perspectives for future research.
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Affiliation(s)
- Yidan Jin
- College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Yahai Lu
- College of Urban and Environmental Sciences, Peking University, Beijing, China
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He J, Luo T, Shi Z, Angelidaki I, Zhang S, Luo G. Microbial shifts in anaerobic digestion towards phenol inhibition with and without hydrochar as revealed by metagenomic binning. JOURNAL OF HAZARDOUS MATERIALS 2022; 440:129718. [PMID: 35952432 DOI: 10.1016/j.jhazmat.2022.129718] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 08/02/2022] [Accepted: 08/04/2022] [Indexed: 06/15/2023]
Abstract
The inhibition of anaerobic digestion (AD) by phenolic compounds is an obstacle to the efficient treatment of organic wastes. Besides, hydrochar produced from hydrothermal liquefaction of biomass has been previously reported to enhance AD. The present study aimed to provide deep insights into the microbial shifts at the species level to phenol (0-1.5 g/L) inhibition in AD of glucose with and without hydrochar by metagenomic analysis. Phenol higher than 1 g/L had severe inhibition on both the amount and rate of methane production in control experiments, while hydrochar significantly enhanced methane production, especially at phenol 1 g/L and 1.5 g/L. From metagenomic analysis, 78 High-quality metagenome-assembled genomes (MAGs) were obtained. Principal components analysis showed that the microbial communities were shifted when phenol concentration was increased to 0.25 g/L in control experiments and 1 g/L in hydrochar experiments. In control experiments, no MAGs involved in acetogenesis were found at phenol 1.5 g/L and Methanothrix sp.FDU243 was also inhibited. However, hydrochar resulted in the maintenance of several MAGs involved in acetogenesis and Methanothrix sp.FDU243 even at phenol 1.5 g/L, ensuring a persistent methane production. Furthermore, 6 phenol-degrading MAGs were identified, shifting dependent on the concentrations of phenol and the presence of hydrochar.
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Affiliation(s)
- Jun He
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes, Shanghai 200438, China
| | - Tao Luo
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes, Shanghai 200438, China
| | - Zhijian Shi
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes, Shanghai 200438, China
| | - Irini Angelidaki
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Kgs Lyngby DK-2800, Denmark
| | - Shicheng Zhang
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes, Shanghai 200438, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Gang Luo
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China; Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes, Shanghai 200438, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
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Westerholm M, Calusinska M, Dolfing J. Syntrophic propionate-oxidizing bacteria in methanogenic systems. FEMS Microbiol Rev 2021; 46:6455325. [PMID: 34875063 PMCID: PMC8892533 DOI: 10.1093/femsre/fuab057] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 12/03/2021] [Indexed: 12/04/2022] Open
Abstract
The mutual nutritional cooperation underpinning syntrophic propionate degradation provides a scant amount of energy for the microorganisms involved, so propionate degradation often acts as a bottleneck in methanogenic systems. Understanding the ecology, physiology and metabolic capacities of syntrophic propionate-oxidizing bacteria (SPOB) is of interest in both engineered and natural ecosystems, as it offers prospects to guide further development of technologies for biogas production and biomass-derived chemicals, and is important in forecasting contributions by biogenic methane emissions to climate change. SPOB are distributed across different phyla. They can exhibit broad metabolic capabilities in addition to syntrophy (e.g. fermentative, sulfidogenic and acetogenic metabolism) and demonstrate variations in interplay with cooperating partners, indicating nuances in their syntrophic lifestyle. In this review, we discuss distinctions in gene repertoire and organization for the methylmalonyl-CoA pathway, hydrogenases and formate dehydrogenases, and emerging facets of (formate/hydrogen/direct) electron transfer mechanisms. We also use information from cultivations, thermodynamic calculations and omic analyses as the basis for identifying environmental conditions governing propionate oxidation in various ecosystems. Overall, this review improves basic and applied understanding of SPOB and highlights knowledge gaps, hopefully encouraging future research and engineering on propionate metabolism in biotechnological processes.
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Affiliation(s)
- Maria Westerholm
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Magdalena Calusinska
- Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology, rue du Brill 41, B-4422 Belvaux, Luxembourg
| | - Jan Dolfing
- Faculty of Energy and Environment, Northumbria University, Newcastle-upon-Tyne, UK
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