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Mühling L, Baur T, Molitor B. Methanothermobacter thermautotrophicus and Alternative Methanogens: Archaea-Based Production. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2024. [PMID: 39363002 DOI: 10.1007/10_2024_270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2024]
Abstract
Methanogenic archaea convert bacterial fermentation intermediates from the decomposition of organic material into methane. This process has relevance in the global carbon cycle and finds application in anthropogenic processes, such as wastewater treatment and anaerobic digestion. Furthermore, methanogenic archaea that utilize hydrogen and carbon dioxide as substrates are being employed as biocatalysts for the biomethanation step of power-to-gas technology. This technology converts hydrogen from water electrolysis and carbon dioxide into renewable natural gas (i.e., methane). The application of methanogenic archaea in bioproduction beyond methane has been demonstrated in only a few instances and is limited to mesophilic species for which genetic engineering tools are available. In this chapter, we discuss recent developments for those existing genetically tractable systems and the inclusion of novel genetic tools for thermophilic methanogenic species. We then give an overview of recombinant bioproduction with mesophilic methanogenic archaea and thermophilic non-methanogenic microbes. This is the basis for discussing putative products with thermophilic methanogenic archaea, specifically the species Methanothermobacter thermautotrophicus. We give estimates of potential conversion efficiencies for those putative products based on a genome-scale metabolic model for M. thermautotrophicus.
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Affiliation(s)
- Lucas Mühling
- Environmental Biotechnology Group, Department of Geosciences, University of Tübingen, Tübingen, Germany
| | - Tina Baur
- Environmental Biotechnology Group, Department of Geosciences, University of Tübingen, Tübingen, Germany
- Cluster of Excellence - Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
| | - Bastian Molitor
- Environmental Biotechnology Group, Department of Geosciences, University of Tübingen, Tübingen, Germany.
- Cluster of Excellence - Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany.
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Prakash O, Dewala SR, Nimonkar Y, Patil SK, Chauhan A, Yadav A, Dhotre DP, Ranade DR. Culture-based and culture-independent approach for the study of the methanogens and obligate anaerobes from different landfill sites. Front Microbiol 2024; 14:1273037. [PMID: 38348306 PMCID: PMC10860756 DOI: 10.3389/fmicb.2023.1273037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 12/27/2023] [Indexed: 02/15/2024] Open
Abstract
The landfill is a cheap way of solid waste management in developing countries. The majority of landfills are non-sanitary and work as open garbage dumping sites and pose threats to public and environmental health. Therefore, an in-depth understanding of the chemistry and microbiology of landfills is imperative to develop the right policies for landfill management. In the current study, we investigated the chemistry and microbiology of three Indian landfill sites using culture-based and culture-independent molecular approaches. Our data indicate that the nature of landfills varies from site to site in terms of chemistry, pollutants, and pathogens. We also enriched and cultivated three methanogens using an optimized medium and constructed two high-quality draft genomes from enriched microbiomes using metagenome-assembled genome approaches. The phylogenomic study of one draft genome showed the highest 93% sequence similarity with members of Methanomassiliicoccaceae and was always enriched with Acholoplasma and Anaerohalosphaera lusitana. Despite all the efforts, we did not isolate it in pure culture and hypothesized that for the cultivation of some not-yet-cultured methanogen, the presence of other organisms plays an important role, and their syntrophic interaction must be discerned for its successful cultivation in the future. Co-cultivation of amino acid-degrading organisms indicates that their co-culture can assist in boosting the growth of methanogens. In addition, our data indicated that landfill leachate contains a heavy load of pollutants and treatment is a must before discharge in nature or use in irrigation or biofertilizer.
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Affiliation(s)
- Om Prakash
- National Centre for Microbial Resource (NCMR), National Centre for Cell Science (NCCS), Pune, India
| | - Sahab Ram Dewala
- National Centre for Microbial Resource (NCMR), National Centre for Cell Science (NCCS), Pune, India
| | - Yogesh Nimonkar
- National Centre for Microbial Resource (NCMR), National Centre for Cell Science (NCCS), Pune, India
| | - Shalaka K. Patil
- National Centre for Microbial Resource (NCMR), National Centre for Cell Science (NCCS), Pune, India
| | - Ashvini Chauhan
- Environmental Biotechnology at the School of the Environment, Florida A&M University, Tallahassee, FL, United States
| | - Amit Yadav
- National Centre for Microbial Resource (NCMR), National Centre for Cell Science (NCCS), Pune, India
| | - Dheeraj P. Dhotre
- National Centre for Microbial Resource (NCMR), National Centre for Cell Science (NCCS), Pune, India
| | - Dilip R. Ranade
- National Centre for Microbial Resource (NCMR), National Centre for Cell Science (NCCS), Pune, India
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Lee C, Ju M, Lee J, Kim S, Kim JY. Long-term inhibition of chlortetracycline antibiotics on anaerobic digestion of swine manure. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 326:116802. [PMID: 36442333 DOI: 10.1016/j.jenvman.2022.116802] [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: 08/09/2022] [Revised: 11/12/2022] [Accepted: 11/13/2022] [Indexed: 06/16/2023]
Abstract
This study aimed to identify whether chronic effects are present in the anaerobic digestion (AD) of swine manure (SM) containing chlortetracycline (CTC), which is one of the major broad-spectrum veterinary antibiotics, and to elucidate the long-term inhibitory effects and recovery from the inhibition based on AD performance and microbial community. Two continuous-stirred tank reactors treating SM with and without CTC spiking (3 mg/L) were operated for 900 days. Due to the degradation and transformation, the total concentration including CTC's epimer and isomer in the test reactor was 1.5 mg/L. The exposure level was determined according to probabilistically estimated concentrations with uncertainties in field conditions. Until the cessation of CTC exposure on day 585, the methane generation of test reactor continuously decreased to 55 ± 17 mL/g-VS/day, 53% that of control. The methane generation and organic removal were not recovered within 300 days after the CTC exposure was stopped. During the experiment, stability parameters such as pH, total ammonium nitrogen, the composition of methane and alkalinity were the same for both reactors. The concentration and composition of VFAs in the test reactor were different with those of control but not in inhibition level. Microbial profiles revealed that reduction in bacterial diversity and changed balance in microbial species resulted in the performance downgrade under the long-term antibiotic pressure. Since it is hard to recover from the inhibition and difficult to predict the inhibition using physicochemical indicators, continuous exposure to CTC needs to be avoided for the sustainable management of AD plants treating SM.
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Affiliation(s)
- Changmin Lee
- Department of Civil and Environmental Engineering, College of Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Munsol Ju
- Department of Living Environment Research, Korea Environment Institute, 370 Sicheong-daero, Sejong, Republic of Korea
| | - Jongkeun Lee
- Department of Environmental and Energy Engineering, College of Engineering, Changwon National University, 20 Changwondaehak-ro, Uichang-gu, Changwon, Gyeongsangnam-do, Republic of Korea
| | - Seunghwan Kim
- Department of Civil and Environmental Engineering, College of Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Jae Young Kim
- Department of Civil and Environmental Engineering, College of Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.
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Blombach F, Matelska D, Fouqueau T, Cackett G, Werner F. Key Concepts and Challenges in Archaeal Transcription. J Mol Biol 2019; 431:4184-4201. [PMID: 31260691 DOI: 10.1016/j.jmb.2019.06.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 06/18/2019] [Accepted: 06/20/2019] [Indexed: 12/17/2022]
Abstract
Transcription is enabled by RNA polymerase and general factors that allow its progress through the transcription cycle by facilitating initiation, elongation and termination. The transitions between specific stages of the transcription cycle provide opportunities for the global and gene-specific regulation of gene expression. The exact mechanisms and the extent to which the different steps of transcription are exploited for regulation vary between the domains of life, individual species and transcription units. However, a surprising degree of conservation is apparent. Similar key steps in the transcription cycle can be targeted by homologous or unrelated factors providing insights into the mechanisms of RNAP and the evolution of the transcription machinery. Archaea are bona fide prokaryotes but employ a eukaryote-like transcription system to express the information of bacteria-like genomes. Thus, archaea provide the means not only to study transcription mechanisms of interesting model systems but also to test key concepts of regulation in this arena. In this review, we discuss key principles of archaeal transcription, new questions that still await experimental investigation, and how novel integrative approaches hold great promise to fill this gap in our knowledge.
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Affiliation(s)
- Fabian Blombach
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, WC1E 6BT, United Kingdom.
| | - Dorota Matelska
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, WC1E 6BT, United Kingdom
| | - Thomas Fouqueau
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, WC1E 6BT, United Kingdom
| | - Gwenny Cackett
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, WC1E 6BT, United Kingdom
| | - Finn Werner
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, WC1E 6BT, United Kingdom.
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Sidhu H, O'Connor G, Ogram A, Kumar K. Bioavailability of biosolids-borne ciprofloxacin and azithromycin to terrestrial organisms: Microbial toxicity and earthworm responses. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 650:18-26. [PMID: 30195128 DOI: 10.1016/j.scitotenv.2018.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 08/29/2018] [Accepted: 09/01/2018] [Indexed: 06/08/2023]
Abstract
Information on bioavailability of two antibiotic TOrCs, ciprofloxacin (CIP) and azithromycin (AZ), to terrestrial organisms is severely limited, especially in the biosolids context. Responses of two terrestrial organisms, earthworms and microbes, to a range of environmentally relevant concentrations of biosolids-borne CIP and AZ were assessed in laboratory incubation studies involving 3H-labeled compounds. Earthworm assessments were based on the Earthworm Sub-chronic Toxicity Test (OCSPP 850.3100). Microbial impacts were assessed using respiration and reverse transcriptase-quantitative PCR (mRNA) analyses of nutrient (N and P) cycling genes as toxicity markers. Antibiotic extractability and stability during incubations were assessed using sequential extractions with CaCl2, methanol:water, and accelerated solvent extraction and analyses using thin layer chromatography. Subsample combustion, in addition to sequential extraction, recovered nearly 100% of the added antibiotic. The two compounds persisted (estimated half-lives ≥ 3 y), but extractable fractions (especially of CIP) decreased over time. Neither biosolids-borne antibiotic significantly impacted overall respiration or N and P cycling. Microbial toxicity responses were minimal; complementary DNA (cDNA) concentrations of ammonia oxidizing bacterial genes were affected, but only initially. Similarly, earthworms showed no apparent response related to toxicity to environmentally relevant (and much greater) concentrations of biosolids-borne CIP and AZ. Earthworms, however, accumulated both compounds, and the bioaccumulation factor (BAF) values (dry weight basis) were ~4 (CIP) and ~7 (AZ) in depurated worms and ~20 (CIP and AZ) in un-depurated worms. The microbial and earthworm responses strongly to moderately correlated with "bioaccessible" fractions of the target TOrCs. The results suggest that biosolids-borne CIP and AZ toxicity to terrestrial microbes and earthworms is minimal, but there is a potential for target TOrC entry into ecological food web.
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Affiliation(s)
- Harmanpreet Sidhu
- Soil and Water Sciences Department, University of Florida, Gainesville, FL 32611, United States of America.
| | - George O'Connor
- Soil and Water Sciences Department, University of Florida, Gainesville, FL 32611, United States of America
| | - Andrew Ogram
- Soil and Water Sciences Department, University of Florida, Gainesville, FL 32611, United States of America
| | - Kuldip Kumar
- Metropolitan Water Reclamation District, Chicago, IL 60611, United States of America
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Cheng DL, Ngo HH, Guo WS, Chang SW, Nguyen DD, Kumar SM, Du B, Wei Q, Wei D. Problematic effects of antibiotics on anaerobic treatment of swine wastewater. BIORESOURCE TECHNOLOGY 2018; 263:642-653. [PMID: 29759819 DOI: 10.1016/j.biortech.2018.05.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/01/2018] [Accepted: 05/02/2018] [Indexed: 06/08/2023]
Abstract
Swine wastewaters with high levels of organic pollutants and antibiotics have become serious environmental concerns. Anaerobic technology is a feasible option for swine wastewater treatment due to its advantage in low costs and bioenergy production. However, antibiotics in swine wastewater have problematic effects on micro-organisms, and the stability and performance of anaerobic processes. Thus, this paper critically reviews impacts of antibiotics on pH, COD removal efficiencies, biogas and methane productions as well as the accumulation of volatile fatty acids (VFAs) in the anaerobic processes. Meanwhile, impacts on the structure of bacteria and methanogens in anaerobic processes are also discussed comprehensively. Furthermore, to better understand the effect of antibiotics on anaerobic processes, detailed information about antimicrobial mechanisms of antibiotics and microbial functions in anaerobic processes is also summarized. Future research on deeper knowledge of the effect of antibiotics on anaerobic processes are suggested to reduce their adverse environmental impacts.
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Affiliation(s)
- D L Cheng
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NWS 2007, Australia
| | - H H Ngo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NWS 2007, Australia.
| | - W S Guo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NWS 2007, Australia
| | - S W Chang
- Department of Environmental Energy & Engineering, Kyonggi University, 442-760, Republic of Korea
| | - D D Nguyen
- Department of Environmental Energy & Engineering, Kyonggi University, 442-760, Republic of Korea
| | - S Mathava Kumar
- Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, Tamilnadu 600036, India
| | - B Du
- School of Resources and Environment, University of Jinan, Jinan 250022, PR China
| | - Q Wei
- Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, PR China
| | - D Wei
- School of Resources and Environment, University of Jinan, Jinan 250022, PR China
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Henderson G, Cook GM, Ronimus RS. Enzyme- and gene-based approaches for developing methanogen-specific compounds to control ruminant methane emissions: a review. ANIMAL PRODUCTION SCIENCE 2018. [DOI: 10.1071/an15757] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Methane emissions from ruminants are of worldwide concern due to their potential to adversely affect climate patterns. Methane emissions can be mitigated in several ways, including dietary manipulation, the use of alternative hydrogen sinks, and by the direct inhibition of methanogens. In the present review, we summarise and emphasise studies where defined chemically synthesised compounds have been used to mitigate ruminant methane emissions by direct targeting of methanogens and discuss the future potential of such inhibitors. We also discuss experiments, where methanogen-specific enzymes and pure cultures of methanobacterial species have been used to aid development of inhibitors. Application of certain compounds can result in dramatic reductions of methane emissions from ruminant livestock, demonstrating ‘proof of principle’ of chemical inhibitors of methanogenesis. More recently, genome sequencing of rumen methanogens has enabled an in-depth analysis of the enzymatic pathways required for methane formation. Chemogenomic methods, similar to those used in the fight against cancer and infectious diseases, can now be used to specifically target a pathway or enzyme in rumen methanogens. However, few rumen methanogen enzymes have been structurally or biochemically characterised. Any compound, whether natural or man-made, that is used as a mitigation strategy will need to be non-toxic to the host animal (and humans), cost-effective, environmentally friendly, and not accumulate in host tissues or milk products. Chemically synthesised inhibitors offer potentially significant advantages, including high levels of sustained inhibition, the ability to be easily and rapidly produced for global markets, and have the potential to be incorporated into slow-release vehicles for grazing animals.
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Battumur U, Yoon Y, Bae GS, Kim CH. Isolation and characterization of new Methanosarcina mazei strains KOR-3, -4, -5, and -6 from an anaerobic digester using pig slurry. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2017; 30:1198-1205. [PMID: 28111440 PMCID: PMC5494495 DOI: 10.5713/ajas.16.0830] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 11/28/2016] [Accepted: 12/29/2016] [Indexed: 11/27/2022]
Abstract
OBJECTIVE An experiment was conducted to isolate and identify new methanogens in Korea from an anaerobic digester that uses pig slurry. METHODS An anaerobic digestate sample was collected from an anaerobic digester using pig slurry. Pre-reduced media were used for the growth and isolation of methanogens. Growth temperature range, pH range, NaCl concentration range, substrate utilization, and antibiotic tolerance were investigated to determine the physiological characteristics of isolated methanogens. The isolates were also examined microscopically for their morphology and Gram-stained. Polymerase chain reaction of 16S rRNA and mcrA gene-based amplicons was used for identification purpose. RESULTS Four strains, designated KOR-3, -4, -5, and -6, were isolated and were non-motile, irregular coccoid, and 0.5 to 1.5 μm in diameter. Moreover, the cell walls of isolated strains were Gram-negative. KOR-3 and KOR-4 strains used acetate for methane production but did not use H2+CO2, formate, or methanol as a growth substrate KOR-5 and KOR-6 strains utilized acetate, methanol, and trimethylamine for methanogenesis but did not use H2+CO2 or formate as a growth substrate. The optimum temperature and pH for growth of four strains were 39°C and 6.8 to 7.2, respectively. The optimum concentration of NaCl for growth of KOR-3, KOR-5, and KOR-6 were 1.0% (w/v). The optimum NaCl concentration for KOR-4 was 0.5% (w/v). All of the strains tolerated ampicillin, penicillin G, kanamycin, streptomycin, and tetracycline; however, chloramphenicol inhibited cell growth. Phylogenetic analysis of 16S rRNA and mcrA genes demonstrated that strains KOR-3, -4, -5, and -6 are related to Methanosarcina mazei (M. mazei, 99% sequence similarity). CONCLUSION On the basis of physiological and phylogenetic characteristics, strains KOR-3, -4, -5, and -6 are proposed to be new strains within the genus Methanosarcina, named M. mazei KOR-3, -4, -5, and -6.
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Affiliation(s)
- Urantulkhuur Battumur
- Graduate School of Future Convergence, Hankyong National University, Anseong 17579,
Korea
- School of Animal Science and Biotechnology, Mongolian University of Life Sciences, Ulaanbaatar 17024,
Mongolia
| | - Youngman Yoon
- Biogas Research Center, Hankyong National University, Anseong 17579,
Korea
| | - Gui Sek Bae
- Department of Animal Science and Technology, Chung-Ang University, Anseong 17546,
Korea
| | - Chang-Hyun Kim
- Biogas Research Center, Hankyong National University, Anseong 17579,
Korea
- Department of Animal Life and Environment Science, Hankyong National University, Anseong 17579,
Korea
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Carey DE, McNamara PJ. Altered antibiotic tolerance in anaerobic digesters acclimated to triclosan or triclocarban. CHEMOSPHERE 2016; 163:22-26. [PMID: 27517129 DOI: 10.1016/j.chemosphere.2016.07.097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/14/2016] [Accepted: 07/29/2016] [Indexed: 06/06/2023]
Abstract
Bench-scale anaerobic digesters were amended to elevated steady-state concentrations of triclosan (850 mg/kg) and triclocarban (150 mg/kg) using a synthetic feed. After more than 9 solids retention time (SRT) values of acclimatization, biomass from each digester (and a control digester that received no antimicrobials) was used to assess the toxicity of three antibiotics. Methane production rate was measured as a surrogate for activity in microcosms that received doses of antibiotics ranging from no-antibiotic to inhibitory concentrations. Biomass amended with triclocarban was more sensitive to tetracycline compared to the control indicating synergistic inhibitory effects between this antibiotic and triclocarban. In contrast, biomass amended with triclosan was able to tolerate statistically higher levels of ciprofloxacin indicating that triclosan can induce functional resistance to ciprofloxacin in an anaerobic digester community.
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Affiliation(s)
- Daniel E Carey
- Department of Civil, Construction and Environmental Engineering, P.O. Box 1881, Marquette University, Milwaukee, WI, USA
| | - Patrick J McNamara
- Department of Civil, Construction and Environmental Engineering, P.O. Box 1881, Marquette University, Milwaukee, WI, USA.
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Du J, Hu Y, Qi W, Zhang Y, Jing Z, Norton M, Li YY. Influence of four antimicrobials on methane-producing archaea and sulfate-reducing bacteria in anaerobic granular sludge. CHEMOSPHERE 2015; 140:184-190. [PMID: 25228232 DOI: 10.1016/j.chemosphere.2014.08.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 07/26/2014] [Accepted: 08/08/2014] [Indexed: 06/03/2023]
Abstract
The influence of Cephalexin (CLX), Tetracycline (TC), Erythromycin (ERY) and Sulfathiazole (ST) on methane-producing archaea (MPA) and sulfate-reducing bacteria (SRB) in anaerobic sludge was investigated using acetate or ethanol as substrate. With antimicrobial concentrations below 400mgL(-1), the relative specific methanogenic activity (SMA) was above 50%, so that the antimicrobials exerted slight effects on archaea. However ERY and ST at 400mgL(-1) caused a 74.5% and 57.6% inhibition to specific sulfidogenic activity (SSA) when the sludge granules were disrupted and ethanol used as substrate. After disruption, microbial tolerance to antimicrobials decreased, but the rate at which MPA utilized acetate and ethanol increased from 0.95gCOD·(gVSS⋅d)(-1) to 1.45gCOD·(gVSS⋅d)(-1) and 0.90gCOD·(gVSS⋅d)(-1) to 1.15gCOD·(gVSS⋅d)(-1) respectively. The ethanol utilization rate for SRB also increased after disruption from 0.35gCOD·(gVSS⋅d)(-1) to 0.46gCOD·(gVSS⋅d)(-1). Removal rates for CLX approaching 20.0% and 25.0% were obtained used acetate and ethanol respectively. The disintegration of granules improved the CLX removal rate to 65% and 78%, but ST was not removed during this process.
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Affiliation(s)
- Jingru Du
- Tohoku University, Graduate School of Environmental Studies, Aoba 6-6-06, Aramaki, Aoba-ku, Sendai, Miyagi, Japan
| | - Yong Hu
- Tohoku University, Graduate School of Environmental Studies, Aoba 6-6-06, Aramaki, Aoba-ku, Sendai, Miyagi, Japan
| | - Weikang Qi
- Tohoku University, Graduate School of Environmental Studies, Aoba 6-6-06, Aramaki, Aoba-ku, Sendai, Miyagi, Japan
| | - Yanlong Zhang
- Tohoku University, Department of Civil and Environmental Engineering, Aoba 6-6-06, Aobayama, Aoba-ku, Sendai, Miyagi, Japan
| | - Zhaoqian Jing
- College of Civil Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Michael Norton
- Tohoku University, Graduate School of Environmental Studies, Aoba 6-6-06, Aramaki, Aoba-ku, Sendai, Miyagi, Japan
| | - Yu-You Li
- Tohoku University, Graduate School of Environmental Studies, Aoba 6-6-06, Aramaki, Aoba-ku, Sendai, Miyagi, Japan; Tohoku University, Department of Civil and Environmental Engineering, Aoba 6-6-06, Aobayama, Aoba-ku, Sendai, Miyagi, Japan; Key Laboratory of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China.
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11
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Navarro SS, Cimpoia R, Bruant G, Guiot SR. Specific inhibitors for identifying pathways for methane production from carbon monoxide by a nonadapted anaerobic mixed culture. Can J Microbiol 2014; 60:407-15. [PMID: 24896194 DOI: 10.1139/cjm-2013-0843] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Specific inhibitors such as 2-bromoethanesulfonate (BES) and vancomycin were employed in activity batch tests to decipher metabolic pathways that are preferentially used by a mixed anaerobic consortium (sludge from an anaerobic digester) to transform carbon monoxide (CO) into methane (CH4). We first evaluated the inhibitory effect of both BES and vancomycin on the microbial community, as well as the efficiency and stability of vancomycin at 35 °C, over time. The activity tests with CO2-H2, CO, glucose, acetate, formate, propionate, butyrate, methanol, and ethanol showed that vancomycin does not inhibit some Gram-negative bacteria, and 50 mmol/L BES effectively blocks CH4 production in the sludge. However, when sludge was incubated with propionate, butyrate, methanol, or ethanol as the sole energy and carbon source, methanogenesis was only partially inhibited by BES. Separate tests showed that 0.07 mmol/L vancomycin is enough to maintain its inhibitory efficiency and stability in the population for at least 32 days at 35 °C. Using the inhibitors above, it was demonstrated that CO conversion to CH4 is an indirect, 2-step process, in which the CO is converted first to acetate and subsequently to CH4.
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Affiliation(s)
- Silvia Sancho Navarro
- a Bioengineering Group, Energy, Mining and Environment, National Research Council Canada, 6100 Royalmount Avenue, Montréal, QC H4P 2R2, Canada
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12
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Stewart CS, Richardson AJ. Enhanced resistance of anaerobic rumen fungi to the ionophores monensin and lasalocid in the presence of methanogenic bacteria. THE JOURNAL OF APPLIED BACTERIOLOGY 1989; 66:85-93. [PMID: 2722716 DOI: 10.1111/j.1365-2672.1989.tb02458.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The presence of Methanobrevibacter smithii altered the susceptibility of the anaerobic fungi Neocallimastix frontalis and Piromonas communis to the carboxylic ionophores monensin and lasalocid. The ionophores depressed growth (measured by chitin accretion), the uptake of glucose and the production of H2, formate and acetate by the fungi growing axenically in semi-solid medium. In the presence of M. smithii, the sensitivity of the fungi to monensin and lasalocid was decreased. For example, the uptake of glucose by N. frontalis strain RE1 in the culture was reduced to 50% of the control value by monensin at 0.5 microgram/ml. In the presence of M. smithii strain PS, approximately three times as much monensin was needed to bring about the same effect. In similar tests, the sensitivity of strain RE1 to lasalocid was decreased about nine-fold in the presence of M. smithii. The effect was not observed if the methanogens were killed by autoclaving before inoculation. It is suggested that the enhanced resistance to ionophores in the presence of M. smithii is a consequence of changes in the energy metabolism of the fungi growing in co-culture.
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Affiliation(s)
- C S Stewart
- Nutrition Division, Rowett Research Institute, Bucksburn, Aberdeen, UK
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Yadav V, Archer DB. Specific inhibition of sulphate-reducing bacteria in methanogenic co-culture. Lett Appl Microbiol 1988. [DOI: 10.1111/j.1472-765x.1988.tb01270.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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