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Gęsicka A, Gutowska N, Palaniappan S, Oleskowicz-Popiel P, Łężyk M. Enrichment of mixed methanotrophic cultures producing polyhydroxyalkanoates (PHAs) from various environmental sources. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:168844. [PMID: 38029989 DOI: 10.1016/j.scitotenv.2023.168844] [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: 07/13/2023] [Revised: 10/31/2023] [Accepted: 11/22/2023] [Indexed: 12/01/2023]
Abstract
Methanotrophic bacteria can use atmospheric methane (CH4) as a sole carbon source for the growth and production of polyhydroxyalkanoates (PHA). The development of CH4 bioconversion processes relies heavily on the selection of an efficient methanotrophic culture. This research assessed the effect of selected growth conditions, such as nitrogen sources on the enrichment of methanotrophic cultures from various environments for PHA accumulation. Nitrate-based medium favoured the culture growth and selection for PHA-producing methanotrophic cultures with Methylocystis sp. as a major genus and accumulation of up to 27 % polyhydroxybutyrate (PHB) in the biomass. Three PHB-producing cultures: enriched from waste activated sludge (AS), peat bog soil (PB) and landfill biocover soil (LB) were then tested for their ability to produce PHA copolymer at different CH4:O2 ratios. All enriched cultures were able to utilise valeric acid as a cosubstrate for the accumulation of PHA with a 3-hydroxyvaleric (3HV) fraction of 21-41 mol% depending on the inoculum source and CH4 concentration. The process performance of selected cultures was evaluated and compared to the culture of reference strain Methylocystis hirsuta DSM 18500. All mixed cultures irrespective of their inoculum source had similar levels of 3HV fraction in the PHA (38 ± 2 mol%). The highest poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) production was observed for AS culture at 10 % CH4 with an accumulation of 27 ± 3 % of dry cell weight (DCW), 3HV fraction of 39 ± 2 mol% and yield of 0.42 ± 0.02 g-PHA/g-substrate.
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Affiliation(s)
- Aleksandra Gęsicka
- Water Supply and Bioeconomy Division, Faculty of Environmental Engineering and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Natalia Gutowska
- Water Supply and Bioeconomy Division, Faculty of Environmental Engineering and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Sivasankar Palaniappan
- Water Supply and Bioeconomy Division, Faculty of Environmental Engineering and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Piotr Oleskowicz-Popiel
- Water Supply and Bioeconomy Division, Faculty of Environmental Engineering and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Mateusz Łężyk
- Water Supply and Bioeconomy Division, Faculty of Environmental Engineering and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland.
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Sana N, Arnepalli DN, Krishnan C. A bio-augmented system with Methylosarcina sp. LC-4 immobilized on bio-carriers: Towards an integrated approach to mitigate and valorize methane emissions from landfills to biodiesel. CHEMOSPHERE 2023; 341:139992. [PMID: 37657707 DOI: 10.1016/j.chemosphere.2023.139992] [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: 04/27/2023] [Revised: 08/02/2023] [Accepted: 08/25/2023] [Indexed: 09/03/2023]
Abstract
Bio-augmented systems based on methanotrophs are indispensable in curbing anthropogenic methane emissions from engineered landfills or dumpsites to curtail rising levels of greenhouse gases. Using a defined methanotroph culture immobilized on an inert material-based bio-carrier makes it possible to harness these methane emissions for creating value-added products, thus contributing to the circular bio-economy. The methane oxidation capacity of the model methanotroph Methylosarcina sp. LC-4, a prospective organism for biodiesel production using methane present in landfill gas, immobilized on several inert bio-carriers, was evaluated to identify a bio-carrier that provided optimum conditions for the process. Among the several bio-carriers evaluated, perlite and vermiculite were selected due to their high specific surface area and superior water-holding capacity, which result in the retention of nutrients and biomass and higher methane elimination capacity. While perlite showed high biomass holding capacity and methane transport, vermiculite supported a high growth of methanotrophs. LC-4 immobilized on perlite and vermiculite as the bio-carrier showed maximum methane elimination capacity (MEC) of 291.3 g m-2 day-1 and 155.5 g m-2 day-1, respectively. The low bed height of only 0.13 m and a short start-up period of 2-4 days are promising for use as alternate daily cover in a landfill. The recovered biomass had 12% (w/w) fatty acid methyl ester (FAME), with a high fraction of (∼85%) of C14-C18 saturated and monounsaturated fatty acids, suitable for biodiesel production. The combination of perlite and vermiculite increased MEC and FAME content levels. The current study demonstrated a new bio-augmented system designed with a pure methanotroph for methane elimination with a short start-up time and the valorization of the assimilated methane.
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Affiliation(s)
- Nivedita Sana
- Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, 600036, India.
| | - Dali Naidu Arnepalli
- Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, 600036, India.
| | - Chandraraj Krishnan
- Department of Biotechnology, Indian Institute of Technology Madras, Chennai, 600036, India.
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Yoon J, Oh MK. Strategies for Biosynthesis of C1 Gas-derived Polyhydroxyalkanoates: A review. BIORESOURCE TECHNOLOGY 2022; 344:126307. [PMID: 34767907 DOI: 10.1016/j.biortech.2021.126307] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 06/13/2023]
Abstract
Biosynthesis of polyhydroxyalkanoates (PHAs) from C1 gases is highly desirable in solving problems such as climate change and microplastic pollution. PHAs are biopolymers synthesized in microbial cells and can be used as alternatives to petroleum-based plastics because of their biodegradability. Because 50% of the cost of PHA production is due to organic carbon sources and salts, the utilization of costless C1 gases as carbon sources is expected to be a promising approach for PHA production. In this review, strategies for PHA production using C1 gases through fermentation and metabolic engineering are discussed. In particular, autotrophs, acetogens, and methanotrophs are strains that can produce PHA from CO2, CO, and CH4. In addition, integrated bioprocesses for the efficient utilization of C1 gases are introduced. Biorefinery processes from C1 gas into bioplastics are prospective strategies with promising potential and feasibility to alleviate environmental issues.
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Affiliation(s)
- Jihee Yoon
- Department of Chemical and Biological Engineering, Korea University, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Min-Kyu Oh
- Department of Chemical and Biological Engineering, Korea University, Seongbuk-gu, Seoul 02841, Republic of Korea.
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Gęsicka A, Oleskowicz-Popiel P, Łężyk M. Recent trends in methane to bioproduct conversion by methanotrophs. Biotechnol Adv 2021; 53:107861. [PMID: 34710553 DOI: 10.1016/j.biotechadv.2021.107861] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 10/11/2021] [Accepted: 10/20/2021] [Indexed: 12/26/2022]
Abstract
Methane is an abundant and low-cost gas with high global warming potential and its use as a feedstock can help mitigate climate change. Variety of valuable products can be produced from methane by methanotrophs in gas fermentation processes. By using methane as a sole carbon source, methanotrophic bacteria can produce bioplastics, biofuels, feed additives, ectoine and variety of other high-value chemical compounds. A lot of studies have been conducted through the years for natural methanotrophs and engineered strains as well as methanotrophic consortia. These have focused on increasing yields of native products as well as proof of concept for the synthesis of new range of chemicals by metabolic engineering. This review shows trends in the research on key methanotrophic bioproducts since 2015. Despite certain limitations of the known production strategies that makes commercialization of methane-based products challenging, there is currently much attention placed on the promising further development.
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Affiliation(s)
- Aleksandra Gęsicka
- Water Supply and Bioeconomy Division, Faculty of Environmental Engineering and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Piotr Oleskowicz-Popiel
- Water Supply and Bioeconomy Division, Faculty of Environmental Engineering and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland.
| | - Mateusz Łężyk
- Water Supply and Bioeconomy Division, Faculty of Environmental Engineering and Energy, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland.
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Kerckhof FM, Sakarika M, Van Giel M, Muys M, Vermeir P, De Vrieze J, Vlaeminck SE, Rabaey K, Boon N. From Biogas and Hydrogen to Microbial Protein Through Co-Cultivation of Methane and Hydrogen Oxidizing Bacteria. Front Bioeng Biotechnol 2021; 9:733753. [PMID: 34527661 PMCID: PMC8435580 DOI: 10.3389/fbioe.2021.733753] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/13/2021] [Indexed: 01/23/2023] Open
Abstract
Increasing efforts are directed towards the development of sustainable alternative protein sources among which microbial protein (MP) is one of the most promising. Especially when waste streams are used as substrates, the case for MP could become environmentally favorable. The risks of using organic waste streams for MP production-the presence of pathogens or toxicants-can be mitigated by their anaerobic digestion and subsequent aerobic assimilation of the (filter-sterilized) biogas. Even though methane and hydrogen oxidizing bacteria (MOB and HOB) have been intensively studied for MP production, the potential benefits of their co-cultivation remain elusive. Here, we isolated a diverse group of novel HOB (that were capable of autotrophic metabolism), and co-cultured them with a defined set of MOB, which could be grown on a mixture of biogas and H2/O2. The combination of MOB and HOB, apart from the CH4 and CO2 contained in biogas, can also enable the valorization of the CO2 that results from the oxidation of methane by the MOB. Different MOB and HOB combinations were grown in serum vials to identify the best-performing ones. We observed synergistic effects on growth for several combinations, and in all combinations a co-culture consisting out of both HOB and MOB could be maintained during five days of cultivation. Relative to the axenic growth, five out of the ten co-cultures exhibited 1.1-3.8 times higher protein concentration and two combinations presented 2.4-6.1 times higher essential amino acid content. The MP produced in this study generally contained lower amounts of the essential amino acids histidine, lysine and threonine, compared to tofu and fishmeal. The most promising combination in terms of protein concentration and essential amino acid profile was Methyloparacoccus murrelli LMG 27482 with Cupriavidus necator LMG 1201. Microbial protein from M. murrelli and C. necator requires 27-67% less quantity than chicken, whole egg and tofu, while it only requires 15% more quantity than the amino acid-dense soybean to cover the needs of an average adult. In conclusion, while limitations still exist, the co-cultivation of MOB and HOB creates an alternative route for MP production leveraging safe and sustainably-produced gaseous substrates.
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Affiliation(s)
- Frederiek-Maarten Kerckhof
- Center for Microbial Ecology and Technology, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Gent, Belgium
| | - Myrsini Sakarika
- Center for Microbial Ecology and Technology, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Gent, Belgium
| | - Marie Van Giel
- Center for Microbial Ecology and Technology, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
| | - Maarten Muys
- Research Group of Sustainable Energy, Air and Water Technology, Department of Bioscience Engineering, University of Antwerp, Antwerpen, Belgium
| | - Pieter Vermeir
- Laboratory of Chemical Analysis, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Jo De Vrieze
- Center for Microbial Ecology and Technology, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
| | - Siegfried E. Vlaeminck
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Gent, Belgium
- Research Group of Sustainable Energy, Air and Water Technology, Department of Bioscience Engineering, University of Antwerp, Antwerpen, Belgium
| | - Korneel Rabaey
- Center for Microbial Ecology and Technology, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Gent, Belgium
| | - Nico Boon
- Center for Microbial Ecology and Technology, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
- Center for Advanced Process Technology for Urban Resource Recovery (CAPTURE), Gent, Belgium
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Karthikeyan OP, Smith TJ, Dandare SU, Parwin KS, Singh H, Loh HX, Cunningham MR, Williams PN, Nichol T, Subramanian A, Ramasamy K, Kumaresan D. Metal(loid) speciation and transformation by aerobic methanotrophs. MICROBIOME 2021; 9:156. [PMID: 34229757 PMCID: PMC8262016 DOI: 10.1186/s40168-021-01112-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 06/09/2021] [Indexed: 05/06/2023]
Abstract
Manufacturing and resource industries are the key drivers for economic growth with a huge environmental cost (e.g. discharge of industrial effluents and post-mining substrates). Pollutants from waste streams, either organic or inorganic (e.g. heavy metals), are prone to interact with their physical environment that not only affects the ecosystem health but also the livelihood of local communities. Unlike organic pollutants, heavy metals or trace metals (e.g. chromium, mercury) are non-biodegradable, bioaccumulate through food-web interactions and are likely to have a long-term impact on ecosystem health. Microorganisms provide varied ecosystem services including climate regulation, purification of groundwater, rehabilitation of contaminated sites by detoxifying pollutants. Recent studies have highlighted the potential of methanotrophs, a group of bacteria that can use methane as a sole carbon and energy source, to transform toxic metal (loids) such as chromium, mercury and selenium. In this review, we synthesise recent advances in the role of essential metals (e.g. copper) for methanotroph activity, uptake mechanisms alongside their potential to transform toxic heavy metal (loids). Case studies are presented on chromium, selenium and mercury pollution from the tanneries, coal burning and artisanal gold mining, respectively, which are particular problems in the developing economy that we propose may be suitable for remediation by methanotrophs. Video Abstract.
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Affiliation(s)
- Obulisamy Parthiba Karthikeyan
- School of Biological Sciences & Institute for Global Food Security, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, UK
- Civil and Environmental Engineering, University of Michigan, Ann Arbor, MI USA
- Department of Engineering Technology, College of Technology, University of Houston, Houston, TX USA
| | - Thomas J. Smith
- Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, UK
| | - Shamsudeen Umar Dandare
- School of Biological Sciences & Institute for Global Food Security, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, UK
| | - Kamaludeen Sara Parwin
- Department of Environmental Sciences, Tamil Nadu Agricultural University, Coimbatore, India
| | - Heetasmin Singh
- Department of Chemistry, University of Guyana, Georgetown, Guyana
| | - Hui Xin Loh
- School of Biological Sciences & Institute for Global Food Security, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, UK
| | - Mark R Cunningham
- School of Biological Sciences & Institute for Global Food Security, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, UK
| | - Paul Nicholas Williams
- School of Biological Sciences & Institute for Global Food Security, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, UK
| | - Tim Nichol
- Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, UK
| | | | | | - Deepak Kumaresan
- School of Biological Sciences & Institute for Global Food Security, Queen’s University Belfast, 19 Chlorine Gardens, Belfast, UK
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Rodríguez Y, Firmino PIM, Pérez V, Lebrero R, Muñoz R. Biogas valorization via continuous polyhydroxybutyrate production by Methylocystis hirsuta in a bubble column bioreactor. WASTE MANAGEMENT (NEW YORK, N.Y.) 2020; 113:395-403. [PMID: 32585559 DOI: 10.1016/j.wasman.2020.06.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/25/2020] [Accepted: 06/11/2020] [Indexed: 06/11/2023]
Abstract
Creating additional value out of biogas during waste treatment has become a priority in past years. Biogas bioconversion into valuable bioproducts such as biopolymers has emerged as a promising strategy. This work assessed the operational feasibility of a bubble column bioreactor (BCB) implemented with gas recirculation and inoculated with a polyhydroxybutyrate (PHB)-producing strain using biogas as substrate. The BCB was initially operated at empty bed residence times (EBRTs) ranging from 30 to 120 min and gas recirculation ratios (R) from 0 to 30 to assess the gas-to-liquid mass transfer and bioconversion of CH4. Subsequently, the BCB was continuously operated at a R of 30 and an EBRT of 60 min under excess of nitrogen and nitrogen feast-famine cycles of 24 h:24 h to trigger PHB synthesis. Gas recirculation played a major role in CH4 gas-liquid transfer, providing almost fourfold higher CH4 elimination capacities (~41 g CH4 m-3 h-1) at the highest R and EBRT of 60 min. The long-term operation under N excess conditions entailed nitrite accumulation (induced by O2 limiting conditions) and concurrent methanotrophic activity inhibition above ~60 mg N-NO2- L-1. Adjusting the N-NO3- supply to match microbial N demand successfully prevented nitrite accumulation. Finally, the N feast-famine 24 h:24 h strategy supported a stable CH4 conversion with a removal efficiency of 70% along with a continuous PHB production, which yielded PHB accumulations of 14.5 ± 2.9% (mg PHB mg-1 total suspended solids × 100). These outcomes represent the first step towards the integration of biogas biorefineries into conventional anaerobic digestion plants.
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Affiliation(s)
- Yadira Rodríguez
- Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain; Institute of Sustainable Processes, Dr. Mergelina s/n, 47011 Valladolid, Spain
| | - Paulo Igor Milen Firmino
- Institute of Sustainable Processes, Dr. Mergelina s/n, 47011 Valladolid, Spain; Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Víctor Pérez
- Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain; Institute of Sustainable Processes, Dr. Mergelina s/n, 47011 Valladolid, Spain
| | - Raquel Lebrero
- Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain; Institute of Sustainable Processes, Dr. Mergelina s/n, 47011 Valladolid, Spain
| | - Raúl Muñoz
- Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain; Institute of Sustainable Processes, Dr. Mergelina s/n, 47011 Valladolid, Spain.
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Luangthongkam P, Strong PJ, Syed Mahamud SN, Evans P, Jensen P, Tyson G, Laycock B, Lant PA, Pratt S. The effect of methane and odd-chain fatty acids on 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) synthesis by a Methylosinus-dominated mixed culture. BIORESOUR BIOPROCESS 2019. [DOI: 10.1186/s40643-019-0285-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
AbstractA methanotrophic community was enriched in a semi-continuous reactor under non-aseptic conditions with methane and ammonia as carbon and nitrogen source. After a year of operation, Methylosinus sp., accounted for 80% relative abundance of the total sequences identified from potential polyhydroxyalkanoates (PHAs) producers, dominated the methane-fed enrichment. Prior to induction of PHA accumulation, cells harvested from the parent reactor contained low level of PHA at 4.0 ± 0.3 wt%. The cells were later incubated in the absence of ammonia with various combinations of methane, propionic acid, and valeric acid to induce biosynthesis of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Previous studies reported that methanotrophic utilization of odd-chain fatty acids for the production of PHAs requires reducing power from methane oxidation. However, our findings demonstrated that the PHB-containing methanotrophic enrichment does not require methane availability to generate 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV)—when odd-chain fatty acids are presented. The enrichment yielded up to 14 wt% PHA with various mole fractions of 3HV monomer depending on the availability of methane and odd-fatty acids. Overall, the addition of valeric acid resulted in a higher PHA content and a higher 3HV fraction. The highest 3HV fraction (up to 65 mol%) was obtained from the methane–valeric acid experiment, which is higher than those previously reported for PHA-producing methanotrophic mixed microbial cultures.
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Shi LD, Wang M, Li ZY, Lai CY, Zhao HP. Dissolved oxygen has no inhibition on methane oxidation coupled to selenate reduction in a membrane biofilm reactor. CHEMOSPHERE 2019; 234:855-863. [PMID: 31252357 DOI: 10.1016/j.chemosphere.2019.06.138] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 06/02/2019] [Accepted: 06/18/2019] [Indexed: 06/09/2023]
Abstract
Methane oxidation coupled to selenate reduction has been suggested as a promising technology to bio-remediate selenium contaminated environments. However, the effect of dissolved oxygen (DO) on this process remained unclear. Here, we investigate the feasibility of selenate removal at two distinct DO concentrations. A membrane biofilm reactor (MBfR) was initially fed with ∼5 mg Se/L and then lowered to ∼1 mg Se/L of selenate, under anoxic condition containing ∼0.2 mg/L of influent DO. Selenate removal reached approximately 90% without selenite accumulation after one-month operation. Then 6-7 mg/L of DO was introduced and showed no apparent effect on selenate reduction in the subsequent operation. Electron microscopy suggested elevated oxygen exposure did not affect microbial shapes. 16S rDNA sequencing showed the aerobic methanotroph Methylocystis increased, while possible selenate reducers, Ignavibacterium and Bradyrhizobium, maintained stable after oxygen boost. Gene analysis indicated that nitrate/nitrite reductases positively correlated with selenate removal flux and were not remarkably affected by oxygen addition. Reversely, enzymes related with aerobic methane oxidation were obviously improved. This study provides a potential technology for selenate removal from oxygenated environments in a methane-based MBfR.
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Affiliation(s)
- Ling-Dong Shi
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Prov Key Lab Water Pollut Control & Envi, Zhejiang University, Hangzhou, Zhejiang, China
| | - Min Wang
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Science, Zhejiang University, Hangzhou, 310058, China
| | - Zi-Yan Li
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Prov Key Lab Water Pollut Control & Envi, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chun-Yu Lai
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Queensland, 4072, Australia
| | - He-Ping Zhao
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Prov Key Lab Water Pollut Control & Envi, Zhejiang University, Hangzhou, Zhejiang, China.
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Bio-conversion of methane into high profit margin compounds: an innovative, environmentally friendly and cost-effective platform for methane abatement. World J Microbiol Biotechnol 2019; 35:16. [PMID: 30617555 DOI: 10.1007/s11274-018-2587-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 12/31/2018] [Indexed: 01/04/2023]
Abstract
Despite the environmental relevance of CH4 and forthcoming stricter regulations, the development of cost-efficient and environmentally friendly technologies for CH4 abatement is still limited. To date, one of the most promising solutions for the mitigation of this important GHG consists of the bioconversion of CH4 into bioproducts with a high profit margin. In this context, methanotrophs have been already proven as cell-factories of some of the most expensive products synthesized by microorganisms. In the case of ectoine (1000 $ kg-1), already described methanotrophic genera such as Methylomicrobium can accumulate up to 20% (ectoine wt-1) using methane as the only carbon source. Moreover, α-methanotrophs, such as Methylosynus and Methylocystis, are able to store bioplastic concentrations up to 50-60% of their total cell content. More than that, methanotrophs are one of the greatest potential producers of methanol and exopolysaccharides. Although this methanotrophic factory could be enhanced throughout metabolic engineering, the valorization of CH4 into valuable metabolites has been already consistently demonstrated under continuous and discontinuous mode, producing more than one compound in the same bioprocess, and using both, single strains and specific consortia. This review states the state-of-the-art of this innovative biotechnological platform by assessing its potential and current limitations.
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van Kruistum H, Bodelier PLE, Ho A, Meima-Franke M, Veraart AJ. Resistance and Recovery of Methane-Oxidizing Communities Depends on Stress Regime and History; A Microcosm Study. Front Microbiol 2018; 9:1714. [PMID: 30108568 PMCID: PMC6080070 DOI: 10.3389/fmicb.2018.01714] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 07/09/2018] [Indexed: 11/21/2022] Open
Abstract
Although soil microbes are responsible for important ecosystem functions, and soils are under increasing environmental pressure, little is known about their resistance and resilience to multiple stressors. Here, we test resistance and recovery of soil methane-oxidizing communities to two different, repeated, perturbations: soil drying, ammonium addition and their combination. In replicated soil microcosms we measured methane oxidation before and after perturbations, while monitoring microbial abundance and community composition using quantitative PCR assays for the bacterial 16S rRNA and pmoA gene, and sequencing of the bacterial 16S rRNA gene. Although microbial community composition changed after soil drying, methane oxidation rates recovered, even after four desiccation events. Moreover, microcosms subjected to soil drying recovered significantly better from ammonium addition compared to microcosms not subjected to soil drying. Our results show the flexibility of microbial communities, even if abundances of dominant populations drop, ecosystem functions can recover. In addition, a history of stress may induce changes in community composition and functioning, which may in turn affect its future tolerance to different stressors.
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Affiliation(s)
- Henri van Kruistum
- Department Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | - Paul L E Bodelier
- Department Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | - Adrian Ho
- Institut für Mikrobiologie, Leibniz Universität Hannover, Hanover, Germany
| | - Marion Meima-Franke
- Department Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | - Annelies J Veraart
- Department Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands.,Department Aquatic Ecology and Environmental Biology, Institute for Water and Wetland Research, Radboud University, Nijmegen, Netherlands
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Zhang T, Wang X, Zhou J, Zhang Y. Enrichments of methanotrophic-heterotrophic cultures with high poly-β-hydroxybutyrate (PHB) accumulation capacities. J Environ Sci (China) 2018; 65:133-143. [PMID: 29548384 DOI: 10.1016/j.jes.2017.03.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/09/2017] [Accepted: 03/13/2017] [Indexed: 06/08/2023]
Abstract
Methanotrophic-heterotrophic communities were selectively enriched from sewage sludge to obtain a mixed culture with high levels of poly-β-hydroxybutyrate (PHB) accumulation capacity from methane. Methane was used as the carbon source, N2 as sole nitrogen source, and oxygen and Cu content were varied. Copper proved essential for PHB synthesis. All cultures enriched with Cu could accumulate high content of PHB (43.2%-45.9%), while only small amounts of PHB were accumulated by cultures enriched without Cu (11.9%-17.5%). Batch assays revealed that communities grown with Cu and a higher O2 content synthesized more PHB, which had a wider optimal CH4:O2 range and produced a high PHB content (48.7%) even though in the presence of N2. In all methanotrophic-heterotrophic communities, both methanotrophic and heterotrophic populations showed the ability to accumulate PHB. Although methane was added as the sole carbon source, heterotrophs dominated with abundances between 77.2% and 85.6%. All methanotrophs detected belonged to type II genera, which formed stable communities with heterotrophs of different PHB production capacities.
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Affiliation(s)
- Tingting Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
| | - Xiaowei Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Jiti Zhou
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
| | - Yu Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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Chidambarampadmavathy K, Karthikeyan OP, Huerlimann R, Maes GE, Heimann K. Response of mixed methanotrophic consortia to different methane to oxygen ratios. WASTE MANAGEMENT (NEW YORK, N.Y.) 2017; 61:220-228. [PMID: 27876290 DOI: 10.1016/j.wasman.2016.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 08/31/2016] [Accepted: 11/04/2016] [Indexed: 05/22/2023]
Abstract
Methane (CH4) and oxygen (air) concentrations affect the CH4 oxidation capacity (MOC) and mixed methanotrophic community structures in compost (fresh) and landfill (age old) top cover soils. A change in the mixed methanotrophic community structure in response has implications for landfill CH4 bio-filter remediation and possible bio-product outcomes (i.e., fatty acid methyl esters (FAME) content and profiles and polyhydroxybutyrate (PHB) contents). Therefore the study aimed to evaluate the effect of variable CH4 to oxygen ratios (10-50% CH4 in air) on mixed methanotrophic community structures enriched from landfill top cover (LB) and compost soils (CB) and to quantify flow on impacts on MOC, total FAME contents and profiles, and PHB accumulation. A stable consortium developed achieving average MOCs of 3.0±0.12, 4.1±0.26, 6.9±0.7, 7.6±1.3 and 9.2±1.2mgCH4g-1DWbiomassh-1 in LB and 2.9±0.04, 5.05±0.32, 6.7±0.31, 7.9±0.61 and 8.6±0.48mgCH4g-1DWbiomassh-1 in CB for a 20day cultivation period at 10, 20, 30, 40 and 50% CH4, respectively. CB at 10% CH4 had a maximal FAME content of 40.5±0.8mgFAMEg-1DWbiomass, while maximal PHB contents (25mgg-1DWbiomass) was observed at 40% CH4 in LB. Despite variable CH4/O2 ratios, the mixed methanotrophic community structures in both LB and CB were relatively stable, dominated by Methylosarcina sp., and Chryseobacterium, suggesting that a resilient consortium had formed which can now be tested in bio-filter operations for CH4 mitigations in landfills.
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Affiliation(s)
- K Chidambarampadmavathy
- College of Science and Engineering, James Cook University, Townsville 4811, Queensland, Australia; Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville 4811, Queensland, Australia
| | - O P Karthikeyan
- College of Science and Engineering, James Cook University, Townsville 4811, Queensland, Australia; Comparative Genomics Centre, James Cook University, Townsville 4811, Queensland, Australia; Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville 4811, Queensland, Australia; Sino-Forest Applied Research Centre for Pearl River Delta Environment (ARCPE), Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region
| | - R Huerlimann
- College of Science and Engineering, James Cook University, Townsville 4811, Queensland, Australia; Comparative Genomics Centre, James Cook University, Townsville 4811, Queensland, Australia; Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville 4811, Queensland, Australia
| | - G E Maes
- College of Science and Engineering, James Cook University, Townsville 4811, Queensland, Australia; Comparative Genomics Centre, James Cook University, Townsville 4811, Queensland, Australia; Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville 4811, Queensland, Australia; Center for Human Genetics, Genomics Core, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - K Heimann
- College of Science and Engineering, James Cook University, Townsville 4811, Queensland, Australia; Comparative Genomics Centre, James Cook University, Townsville 4811, Queensland, Australia; Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville 4811, Queensland, Australia; Centre for Bio-discovery and Molecular Development of Therapeutics, James Cook University, Townsville 4811, Queensland, Australia.
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14
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Karthikeyan OP, Saravanan N, Cirés S, Alvarez-Roa C, Razaghi A, Chidambarampadmavathy K, Velu C, Subashchandrabose G, Heimann K. Culture scale-up and immobilisation of a mixed methanotrophic consortium for methane remediation in pilot-scale bio-filters. ENVIRONMENTAL TECHNOLOGY 2017; 38:474-482. [PMID: 27267085 DOI: 10.1080/09593330.2016.1198424] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Robust methanotrophic consortia for methane (CH4) remediation and by-product development are presently not readily available for industrial use. In this study, a mixed methanotrophic consortium (MMC), sequentially enriched from a marine sediment, was assessed for CH4 removal efficiency and potential biomass-generated by-product development. Suitable packing material for bio-filters to support MMC biofilm establishment and growth was also evaluated. The enriched MMC removed ∼7-13% CH4 under a very high gas flow rate (2.5 L min-1; 20-25% CH4) in continuous-stirred tank reactors (∼10 L working volume) and the biomass contained long-chain fatty acids (i.e. C16 and C18). Cultivation of the MMC on plastic bio-balls abated ∼95-97% CH4 in pilot-scale non-sterile outdoor-operated bio-filters (0.1 L min-1; 1% CH4). Contamination by cyanobacteria had beneficial effects on treating low-level CH4, by providing additional oxygen for methane oxidation by MMC, suggesting that the co-cultivation of MMC with cyanobacterial mats does not interfere with and may actually be beneficial for remediation of CH4 and CO2 at industrial scale.
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Affiliation(s)
- Obulisamy Parthiba Karthikeyan
- a College of Science and Engineering , James Cook University , Townsville , Queensland , Australia
- b Comparative Genomics Centre , James Cook University , Townsville , Queensland , Australia
- c Department of Biology, Sino-Forest Applied Research Centre for Pearl River Delta Environment , Hong Kong Baptist University , Kowloon Tong , Hong Kong
| | - Nadarajan Saravanan
- a College of Science and Engineering , James Cook University , Townsville , Queensland , Australia
| | - Samuel Cirés
- a College of Science and Engineering , James Cook University , Townsville , Queensland , Australia
- b Comparative Genomics Centre , James Cook University , Townsville , Queensland , Australia
- e Departamento de Biología , Universidad Autónoma de Madrid , Madrid , Spain
| | - Carlos Alvarez-Roa
- a College of Science and Engineering , James Cook University , Townsville , Queensland , Australia
| | - Ali Razaghi
- a College of Science and Engineering , James Cook University , Townsville , Queensland , Australia
| | | | - Chinnathambi Velu
- a College of Science and Engineering , James Cook University , Townsville , Queensland , Australia
| | | | - Kirsten Heimann
- a College of Science and Engineering , James Cook University , Townsville , Queensland , Australia
- b Comparative Genomics Centre , James Cook University , Townsville , Queensland , Australia
- d Centre for Bio-discovery and Molecular Development of Therapeutics , James Cook University , Townsville , Queensland , Australia
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15
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Fernandez-Gonzalez N, Huber JA, Vallino JJ. Microbial Communities Are Well Adapted to Disturbances in Energy Input. mSystems 2016; 1:e00117-16. [PMID: 27822558 PMCID: PMC5080406 DOI: 10.1128/msystems.00117-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 08/16/2016] [Indexed: 11/20/2022] Open
Abstract
Although microbial systems are well suited for studying concepts in ecological theory, little is known about how microbial communities respond to long-term periodic perturbations beyond diel oscillations. Taking advantage of an ongoing microcosm experiment, we studied how methanotrophic microbial communities adapted to disturbances in energy input over a 20-day cycle period. Sequencing of bacterial 16S rRNA genes together with quantification of microbial abundance and ecosystem function were used to explore the long-term dynamics (510 days) of methanotrophic communities under continuous versus cyclic chemical energy supply. We observed that microbial communities appeared inherently well adapted to disturbances in energy input and that changes in community structure in both treatments were more dependent on internal dynamics than on external forcing. The results also showed that the rare biosphere was critical to seeding the internal community dynamics, perhaps due to cross-feeding or other strategies. We conclude that in our experimental system, internal feedbacks were more important than external drivers in shaping the community dynamics over time, suggesting that ecosystems can maintain their function despite inherently unstable community dynamics. IMPORTANCE Within the broader ecological context, biological communities are often viewed as stable and as only experiencing succession or replacement when subject to external perturbations, such as changes in food availability or the introduction of exotic species. Our findings indicate that microbial communities can exhibit strong internal dynamics that may be more important in shaping community succession than external drivers. Dynamic "unstable" communities may be important for ecosystem functional stability, with rare organisms playing an important role in community restructuring. Understanding the mechanisms responsible for internal community dynamics will certainly be required for understanding and manipulating microbiomes in both host-associated and natural ecosystems.
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Affiliation(s)
| | - Julie A. Huber
- The Josephine Bay Paul Center, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Joseph J. Vallino
- Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
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Bonartsev AP, Zharkova II, Yakovlev SG, Myshkina VL, Mahina TK, Voinova VV, Zernov AL, Zhuikov VA, Akoulina EA, Ivanova EV, Kuznetsova ES, Shaitan KV, Bonartseva GA. Biosynthesis of poly(3-hydroxybutyrate) copolymers by Azotobacter chroococcum 7B: A precursor feeding strategy. Prep Biochem Biotechnol 2016; 47:173-184. [PMID: 27215309 DOI: 10.1080/10826068.2016.1188317] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A precursor feeding strategy for effective biopolymer producer strain Azotobacter chroococcum 7B was used to synthesize various poly(3-hydroxybutyrate) (PHB) copolymers. We performed experiments on biosynthesis of PHB copolymers by A. chroococcum 7B using various precursors: sucrose as the primary carbon source, various carboxylic acids and ethylene glycol (EG) derivatives [diethylene glycol (DEG), triethylene glycol (TEG), poly(ethylene glycol) (PEG) 300, PEG 400, PEG 1000] as additional carbon sources. We analyzed strain growth parameters including biomass and polymer yields as well as molecular weight and monomer composition of produced copolymers. We demonstrated that A. chroococcum 7B was able to synthesize copolymers using carboxylic acids with the length less than linear 6C, including poly(3-hydroxybutyrate-co-3-hydroxy-4-methylvalerate) (PHB-4MHV) using Y-shaped 6C 3-methylvaleric acid as precursor as well as EG-containing copolymers: PHB-DEG, PHB-TEG, PHB-PEG, and PHB-HV-PEG copolymers using short-chain PEGs (with n ≤ 9) as precursors. It was shown that use of the additional carbon sources caused inhibition of cell growth, decrease in polymer yields, fall in polymer molecular weight, decrease in 3-hydroxyvalerate content in produced PHB-HV-PEG copolymer, and change in bacterial cells morphology that were depended on the nature of the precursors (carboxylic acids or EG derivatives) and the timing of its addition to the growth medium.
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Affiliation(s)
- A P Bonartsev
- a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia.,b Faculty of Biology , Moscow State University , Moscow , Russia.,c Department of Maxillofacial and Oral Surgery , Nizhny Novgorod State Medical Academy , Nizhny Novgorod , Russia
| | - I I Zharkova
- b Faculty of Biology , Moscow State University , Moscow , Russia
| | - S G Yakovlev
- a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia.,c Department of Maxillofacial and Oral Surgery , Nizhny Novgorod State Medical Academy , Nizhny Novgorod , Russia
| | - V L Myshkina
- a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia
| | - T K Mahina
- a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia
| | - V V Voinova
- b Faculty of Biology , Moscow State University , Moscow , Russia.,c Department of Maxillofacial and Oral Surgery , Nizhny Novgorod State Medical Academy , Nizhny Novgorod , Russia
| | - A L Zernov
- a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia.,c Department of Maxillofacial and Oral Surgery , Nizhny Novgorod State Medical Academy , Nizhny Novgorod , Russia
| | - V A Zhuikov
- a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia.,c Department of Maxillofacial and Oral Surgery , Nizhny Novgorod State Medical Academy , Nizhny Novgorod , Russia
| | - E A Akoulina
- a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia
| | - E V Ivanova
- b Faculty of Biology , Moscow State University , Moscow , Russia
| | - E S Kuznetsova
- b Faculty of Biology , Moscow State University , Moscow , Russia
| | - K V Shaitan
- b Faculty of Biology , Moscow State University , Moscow , Russia
| | - G A Bonartseva
- a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia
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17
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Karthikeyan OP, Chidambarampadmavathy K, Nadarajan S, Heimann K. Influence of nutrients on oxidation of low level methane by mixed methanotrophic consortia. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:4346-4357. [PMID: 26867685 DOI: 10.1007/s11356-016-6174-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Accepted: 01/25/2016] [Indexed: 06/05/2023]
Abstract
Low-level methane emissions from coal mine ventilation air (CMV-CH4; i.e., 1 % CH4) can significantly contribute to global climate change, and therefore, treatment is important to reduce impacts. To investigate CMV-CH4 abatement potential, five different mixed methanotrohic consortia (MMCs) were established from soil/sediment sources, i.e., landfill top cover soil, bio-solid compost, vegetated humus soil, estuarine and marine sediments. Enrichment conditions for MMCs were as follows: nitrate mineral salt (NMS) medium, pH ~ 6.8; 25 °C; 20-25 % CH4; agitation 200 rpm; and culture period 20 days, in mini-bench-top bioreactors. The enriched cultures were supplemented with extra carbon (methanol 0.5-1.5 %, formate 5-15 mM, and acetate 5-15 mM), nitrogen (nitrate 0.5-1.5 g L(-1), ammonium 0.1-0.5 g L(-1), or urea: 0.1-0.5 g L(-1)), and trace elements (copper 1-5 μM, iron 1-5 μM, and zinc 1-5 μM) in different batch experiments to improve low-level CH4 abatement. Average CH4 oxidation capacities (MOCs) of MMCs varied between 1.712 ± 0.032 and 1.963 ± 0.057 mg g(-1)DWbiomass h(-1). Addition of formate improved the MOCs of MMCs, but the dose-response varied for different MMCs. Acetate, nitrate and copper had no significant effect on MOCs, while addition of methanol, ammonium, urea, iron and zinc impacted negatively. Overall, MMCs enriched from marine sediments and landfill top cover soil showed high MOCs which were largely resilient to nutrient supplementation, suggesting a strong potential for biofilter development for industrial low-level CH4 abatement, such as those present in CMV.
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Affiliation(s)
- Obulisamy Parthiba Karthikeyan
- College of Marine and Environmental Sciences, James Cook University, Townsville, 4811, Queensland, Australia
- Comparative Genomics Centre, James Cook University, Townsville, 4811, Queensland, Australia
| | | | - Saravanan Nadarajan
- College of Marine and Environmental Sciences, James Cook University, Townsville, 4811, Queensland, Australia
| | - Kirsten Heimann
- College of Marine and Environmental Sciences, James Cook University, Townsville, 4811, Queensland, Australia.
- Comparative Genomics Centre, James Cook University, Townsville, 4811, Queensland, Australia.
- Centre for Bio-discovery and Molecular Development of Therapeutics, James Cook University, Townsville, 4811, Queensland, Australia.
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18
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Strong PJ, Laycock B, Mahamud SNS, Jensen PD, Lant PA, Tyson G, Pratt S. The Opportunity for High-Performance Biomaterials from Methane. Microorganisms 2016; 4:E11. [PMID: 27681905 PMCID: PMC5029516 DOI: 10.3390/microorganisms4010011] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 01/15/2016] [Accepted: 01/22/2016] [Indexed: 01/18/2023] Open
Abstract
Polyhydroxyalkanoate (PHA) biopolymers are widely recognised as outstanding candidates to replace conventional petroleum-derived polymers. Their mechanical properties are good and can be tailored through copolymer composition, they are biodegradable, and unlike many alternatives, they do not rely on oil-based feedstocks. Further, they are the only commodity polymer that can be synthesised intracellularly, ensuring stereoregularity and high molecular weight. However, despite offering enormous potential for many years, they are still not making a significant impact. This is broadly because commercial uptake has been limited by variable performance (inconsistent polymer properties) and high production costs of the raw polymer. Additionally, the main type of PHA produced naturally is poly-3-hydroxybutyrate (PHB), which has limited scope due to its brittle nature and low thermal stability, as well as its tendency to embrittle over time. Production cost is strongly impacted by the type of the feedstock used. In this article we consider: the production of PHAs from methanotrophs using methane as a cost-effective substrate; the use of mixed cultures, as opposed to pure strains; and strategies to generate a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer (PHBV), which has more desirable qualities such as toughness and elasticity.
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Affiliation(s)
- Peter James Strong
- Centre for Solid Waste Bioprocessing, School of Civil Engineering and School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia.
| | - Bronwyn Laycock
- School of Chemical Engineering, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia.
| | | | - Paul Douglas Jensen
- Advanced Water Management Centre, The University of Queensland, Brisbane, Queensland 4072, Australia.
| | - Paul Andrew Lant
- School of Chemical Engineering, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia.
| | - Gene Tyson
- Australian Centre for Ecogenomics, The University of Queensland, Brisbane, Queensland 4072, Australia.
| | - Steven Pratt
- School of Chemical Engineering, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia.
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