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Leng L, Yang P, Singh S, Zhuang H, Xu L, Chen WH, Dolfing J, Li D, Zhang Y, Zeng H, Chu W, Lee PH. A review on the bioenergetics of anaerobic microbial metabolism close to the thermodynamic limits and its implications for digestion applications. BIORESOURCE TECHNOLOGY 2018; 247:1095-1106. [PMID: 28958887 DOI: 10.1016/j.biortech.2017.09.103] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/09/2017] [Accepted: 09/15/2017] [Indexed: 05/24/2023]
Abstract
The exploration of the energetics of anaerobic digestion systems can reveal how microorganisms cooperate efficiently for cell growth and methane production, especially under low-substrate conditions. The establishment of a thermodynamically interdependent partnership, called anaerobic syntrophy, allows unfavorable reactions to proceed. Interspecies electron transfer and the concentrations of electron carriers are crucial for maintaining this mutualistic activity. This critical review summarizes the functional microorganisms and syntroph partners, particularly in the metabolic pathways and energy conservation of syntrophs. The kinetics and thermodynamics of propionate degradation to methane, reversibility of the acetate oxidation process, and estimation of microbial growth are summarized. The various routes of interspecies electron transfer, reverse electron transfer, and Poly-β-hydroxyalkanoate formation in the syntrophic community are also reviewed. Finally, promising and critical directions of future research are proposed. Fundamental insight in the activities and interactions involved in AD systems could serve as a guidance for engineered systems optimization and upgrade.
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Affiliation(s)
- Ling Leng
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Peixian Yang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Shubham Singh
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Huichuan Zhuang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Linji Xu
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Wen-Hsing Chen
- Department of Environmental Engineering, National Ilan University, Yilan 260, Taiwan
| | - Jan Dolfing
- School of Civil Engineering and Geosciences, Newcastle University, Newcastle NE1 7RU, UK
| | - Dong Li
- Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China
| | - Yan Zhang
- Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China
| | - Huiping Zeng
- Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China
| | - Wei Chu
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Po-Heng Lee
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
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Sidhu C, Vikram S, Pinnaka AK. Unraveling the Microbial Interactions and Metabolic Potentials in Pre- and Post-treated Sludge from a Wastewater Treatment Plant Using Metagenomic Studies. Front Microbiol 2017; 8:1382. [PMID: 28769920 PMCID: PMC5515832 DOI: 10.3389/fmicb.2017.01382] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 07/07/2017] [Indexed: 01/06/2023] Open
Abstract
Sewage waste represents an ecosystem of complex and interactive microbial consortia which proliferate with different kinetics according to their individual genetic as well as metabolic potential. We performed metagenomic shotgun sequencing on Ion-Torrent platform, to explore the microbial community structure, their biological interactions and associated functional capacity of pre-treated/raw sludge (RS) and post-treated/dried sludge (DS) of wastewater treatment plant. Bacterial phylotypes belonging to Epsilonproteobacteria (∼45.80%) dominated the RS with relatively few Archaea (∼1.94%) whereas DS has the dominance of beta- (30.23%) and delta- (13.38%) classes of Proteobacteria with relatively greater abundance of Archaea (∼7.18%). In particular, Epsilonproteobacteria appears as a primary energy source in RS and sulfur-reducing bacteria with methanogens seems to be in the potential syntrophic association in DS. These interactions could be ultimately responsible for carrying out amino-acid degradation, aromatic compound degradation and degradation of propionate and butyrate in DS. Our data also reveal the presence of key genes in the sludge microbial community responsible for degradation of polycyclic aromatic hydrocarbons. Potential pathogenic microbes and genes for the virulence factors were found to be relatively abundant in RS which clearly reflect the necessity of treatment of RS. After treatment, potential pathogens load was reduced, indicating the sludge hygienisation in DS. Additionally, the interactions found in this study would reveal the biological and environmental cooperation among microbial communities for domestic wastewater treatment.
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Affiliation(s)
- Chandni Sidhu
- Microbial Type Culture Collection and Gene Bank, Council of Scientific and Industrial Research-Institute of Microbial TechnologyChandigarh, India
| | - Surendra Vikram
- Microbial Type Culture Collection and Gene Bank, Council of Scientific and Industrial Research-Institute of Microbial TechnologyChandigarh, India.,Centre for Microbial Ecology and Genomics, Department of Genetics, University of PretoriaPretoria, South Africa
| | - Anil Kumar Pinnaka
- Microbial Type Culture Collection and Gene Bank, Council of Scientific and Industrial Research-Institute of Microbial TechnologyChandigarh, India
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Delforno TP, Lacerda GV, Sierra-Garcia IN, Okada DY, Macedo TZ, Varesche MBA, Oliveira VM. Metagenomic analysis of the microbiome in three different bioreactor configurations applied to commercial laundry wastewater treatment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 587-588:389-398. [PMID: 28249753 DOI: 10.1016/j.scitotenv.2017.02.170] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 02/20/2017] [Accepted: 02/20/2017] [Indexed: 05/10/2023]
Abstract
The taxonomic and functional diversity of three different biological reactors (fluidized bed reactor, FBR; up-flow anaerobic sludge blanket reactor, UASB; and expanded granular sludge bed reactor, EGSB) used for commercial laundry wastewater treatment was investigated using metagenome shotgun sequencing. Metagenomes were sequenced on the Illumina Hiseq platform and were analyzed using MG-RAST, STAMP and PAST software. The EGSB and UASB reactors were more closely related based on taxonomic and functional profiles, likely due to similar granular sludge and procedures adopted to ensure anaerobic conditions. The EGSB and UASB reactors showed a predominance of methanogens and genes related to methanogenesis, with a prevalence of the acetoclastic pathway, in addition to the peripheral and central O2-independent pathways for aromatic compound degradation. By contrast, FBR showed a dominance of aerobic microbiota and pathways for O2-dependent aromatic compound degradation. Therefore, although the reactors showed similar surfactant removal levels, the microbial composition, functional diversity and aromatic compound degradation pathways were significantly distinct.
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Affiliation(s)
- T P Delforno
- Microbial Resources Division, Research Center for Chemistry, Biology and Agriculture (CPQBA), Campinas University - UNICAMP, Campinas, SP CEP 13081-970, Brazil.
| | - G V Lacerda
- Microbial Resources Division, Research Center for Chemistry, Biology and Agriculture (CPQBA), Campinas University - UNICAMP, Campinas, SP CEP 13081-970, Brazil.
| | - I N Sierra-Garcia
- Microbial Resources Division, Research Center for Chemistry, Biology and Agriculture (CPQBA), Campinas University - UNICAMP, Campinas, SP CEP 13081-970, Brazil.
| | - D Y Okada
- School of Technology, Division of Technology in Environment Sanitation, Campinas University - UNICAMP, Limeira, SP CEP 13484-332, Brazil.
| | - T Z Macedo
- Laboratory of Biological Processes, Department of Hydraulics and Sanitation, Engineering School of São Carlos - University of São Paulo (EESC - USP), Campus II, São Carlos, SP CEP 13563-120, Brazil.
| | - M B A Varesche
- Laboratory of Biological Processes, Department of Hydraulics and Sanitation, Engineering School of São Carlos - University of São Paulo (EESC - USP), Campus II, São Carlos, SP CEP 13563-120, Brazil.
| | - V M Oliveira
- Microbial Resources Division, Research Center for Chemistry, Biology and Agriculture (CPQBA), Campinas University - UNICAMP, Campinas, SP CEP 13081-970, Brazil.
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Lovley DR. Happy together: microbial communities that hook up to swap electrons. ISME JOURNAL 2016; 11:327-336. [PMID: 27801905 DOI: 10.1038/ismej.2016.136] [Citation(s) in RCA: 179] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 08/29/2016] [Accepted: 09/04/2016] [Indexed: 12/22/2022]
Abstract
The discovery of direct interspecies electron transfer (DIET) and cable bacteria has demonstrated that microbial cells can exchange electrons over long distances (μm-cm) through electrical connections. For example, in the presence of cable bacteria electrons are rapidly transported over centimeter distances, coupling the oxidation of reduced sulfur compounds in anoxic sediments to oxygen reduction in overlying surficial sediments. Bacteria and archaea wired for DIET are found in anaerobic methane-producing and methane-consuming communities. Electrical connections between gut microbes and host cells have also been proposed. Iterative environmental and defined culture studies on methanogenic communities revealed the importance of electrically conductive pili and c-type cytochromes in natural electrical grids, and demonstrated that conductive carbon materials and magnetite can substitute for these biological connectors to facilitate DIET. This understanding has led to strategies to enhance and stabilize anaerobic digestion. Key unknowns warranting further investigation include elucidation of the archaeal electrical connections facilitating DIET-based methane production and consumption; and the mechanisms for long-range electron transfer through cable bacteria. A better understanding of mechanisms for cell-to-cell electron transfer could facilitate the hunt for additional electrically connected microbial communities with omics approaches and could advance spin-off applications such as the development of sustainable bioelectronics materials and bioelectrochemical technologies.
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Affiliation(s)
- Derek R Lovley
- Department of Microbiology, Morrill IV N Science Center, University of Massachusetts, Amherst, MA, USA
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Purohit HJ, Kapley A, Khardenavis A, Qureshi A, Dafale NA. Insights in Waste Management Bioprocesses Using Genomic Tools. ADVANCES IN APPLIED MICROBIOLOGY 2016; 97:121-170. [PMID: 27926430 DOI: 10.1016/bs.aambs.2016.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Microbial capacities drive waste stabilization and resource recovery in environmental friendly processes. Depending on the composition of waste, a stress-mediated selection process ensures a scenario that generates a specific enrichment of microbial community. These communities dynamically change over a period of time while keeping the performance through the required utilization capacities. Depending on the environmental conditions, these communities select the appropriate partners so as to maintain the desired functional capacities. However, the complexities of these organizations are difficult to study. Individual member ratios and sharing of genetic intelligence collectively decide the enrichment and survival of these communities. The next-generation sequencing options with the depth of structure and function analysis have emerged as a tool that could provide the finer details of the underlying bioprocesses associated and shared in environmental niches. These tools can help in identification of the key biochemical events and monitoring of expression of associated phenotypes that will support the operation and maintenance of waste management systems. In this chapter, we link genomic tools with process optimization and/or management, which could be applied for decision making and/or upscaling. This review describes both, the aerobic and anaerobic, options of waste utilization process with the microbial community functioning as flocs, granules, or biofilms. There are a number of challenges involved in harnessing the microbial community intelligence with associated functional plasticity for efficient extension of microbial capacities for resource recycling and waste management. Mismanaged wastes could lead to undesired genotypes such as antibiotic/multidrug-resistant microbes.
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Affiliation(s)
- H J Purohit
- National Environmental Engineering Research Institute, CSIR, Nagpur, India
| | - A Kapley
- National Environmental Engineering Research Institute, CSIR, Nagpur, India
| | - A Khardenavis
- National Environmental Engineering Research Institute, CSIR, Nagpur, India
| | - A Qureshi
- National Environmental Engineering Research Institute, CSIR, Nagpur, India
| | - N A Dafale
- National Environmental Engineering Research Institute, CSIR, Nagpur, India
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