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Rocha RA, Alexandrov K, Scott C. Rare earth elements in biology: From biochemical curiosity to solutions for extractive industries. Microb Biotechnol 2024; 17:e14503. [PMID: 38829373 PMCID: PMC11146143 DOI: 10.1111/1751-7915.14503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/28/2024] [Accepted: 05/11/2024] [Indexed: 06/05/2024] Open
Abstract
Rare earth elements (REEs) are critical for our modern lifestyles and the transition to a low-carbon economy. Recent advances in our understanding of the role of REEs in biology, particularly methylotrophy, have provided opportunities to explore biotechnological innovations to improve REE mining and recycling. In addition to bacterial accumulation and concentration of REEs, biological REE binders, including proteins (lanmodulin, lanpepsy) and small molecules (metallophores and cofactors) have been identified that enable REE concentration and separation. REE-binding proteins have also been used in several mechanistically distinct REE biosensors, which have potential application in mining and medicine. Notably, the role of REEs in biology has only been known for a decade, suggesting their considerable scope for developing new understanding and novel applications.
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Affiliation(s)
- Raquel A. Rocha
- ARC Centre of Excellence in Synthetic BiologyCanberraAustralian Capital TerritoryAustralia
- CSIRO Advanced Engineering Biology Future Science Platform, Black Mountain Science and Innovation ParkCanberraAustralian Capital TerritoryAustralia
| | - Kirill Alexandrov
- ARC Centre of Excellence in Synthetic BiologyCanberraAustralian Capital TerritoryAustralia
- Centre for Agriculture and the BioeconomyQueensland University of TechnologyBrisbaneQueenslandAustralia
- School of Biology and Environmental ScienceQueensland University of TechnologyBrisbaneQueenslandAustralia
| | - Colin Scott
- ARC Centre of Excellence in Synthetic BiologyCanberraAustralian Capital TerritoryAustralia
- CSIRO Advanced Engineering Biology Future Science Platform, Black Mountain Science and Innovation ParkCanberraAustralian Capital TerritoryAustralia
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2
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Liu R, Wei Z, Dong W, Wang R, Adams JM, Yang L, Krause SMB. Unraveling the impact of lanthanum on methane consuming microbial communities in rice field soils. Front Microbiol 2024; 15:1298154. [PMID: 38322316 PMCID: PMC10844099 DOI: 10.3389/fmicb.2024.1298154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 01/03/2024] [Indexed: 02/08/2024] Open
Abstract
The discovery of the lanthanide requiring enzymes in microbes was a significant scientific discovery that opened a whole new avenue of biotechnological research of this important group of metals. However, the ecological impact of lanthanides on microbial communities utilizing methane (CH4) remains largely unexplored. In this study, a laboratory microcosm model experiment was performed using rice field soils with different pH origins (5.76, 7.2, and 8.36) and different concentrations of La3+ in the form of lanthanum chloride (LaCl3). Results clearly showed that CH4 consumption was inhibited by the addition of La3+ but that the response depended on the soil origin and pH. 16S rRNA gene sequencing revealed the genus Methylobacter, Methylosarcina, and Methylocystis as key players in CH4 consumption under La3+ addition. We suggest that the soil microbiome involved in CH4 consumption can generally tolerate addition of high concentrations of La3+, and adjustments in community composition ensured ecosystem functionality over time. As La3+ concentrations increase, the way that the soil microbiome reacts may not only differ within the same environment but also vary when comparing different environments, underscoring the need for further research into this subject.
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Affiliation(s)
- Ruyan Liu
- School of Ecology and Environmental Sciences, East China Normal University, Shanghai, China
| | - Ziting Wei
- School of Ecology and Environmental Sciences, East China Normal University, Shanghai, China
| | - Wanying Dong
- School of Ecology and Environmental Sciences, East China Normal University, Shanghai, China
| | - Rui Wang
- School of Ecology and Environmental Sciences, East China Normal University, Shanghai, China
| | - Jonathan M. Adams
- School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing, China
| | - Lin Yang
- School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing, China
| | - Sascha M. B. Krause
- School of Ecology and Environmental Sciences, East China Normal University, Shanghai, China
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3
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Wutkowska M, Tláskal V, Bordel S, Stein LY, Nweze JA, Daebeler A. Leveraging genome-scale metabolic models to understand aerobic methanotrophs. THE ISME JOURNAL 2024; 18:wrae102. [PMID: 38861460 PMCID: PMC11195481 DOI: 10.1093/ismejo/wrae102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/20/2024] [Accepted: 06/10/2024] [Indexed: 06/13/2024]
Abstract
Genome-scale metabolic models (GEMs) are valuable tools serving systems biology and metabolic engineering. However, GEMs are still an underestimated tool in informing microbial ecology. Since their first application for aerobic gammaproteobacterial methane oxidizers less than a decade ago, GEMs have substantially increased our understanding of the metabolism of methanotrophs, a microbial guild of high relevance for the natural and biotechnological mitigation of methane efflux to the atmosphere. Particularly, GEMs helped to elucidate critical metabolic and regulatory pathways of several methanotrophic strains, predicted microbial responses to environmental perturbations, and were used to model metabolic interactions in cocultures. Here, we conducted a systematic review of GEMs exploring aerobic methanotrophy, summarizing recent advances, pointing out weaknesses, and drawing out probable future uses of GEMs to improve our understanding of the ecology of methane oxidizers. We also focus on their potential to unravel causes and consequences when studying interactions of methane-oxidizing bacteria with other methanotrophs or members of microbial communities in general. This review aims to bridge the gap between applied sciences and microbial ecology research on methane oxidizers as model organisms and to provide an outlook for future studies.
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Affiliation(s)
- Magdalena Wutkowska
- Institute of Soil Biology and Biogeochemistry, Biology Centre CAS, 370 05 České Budějovice, Czech Republic
| | - Vojtěch Tláskal
- Institute of Soil Biology and Biogeochemistry, Biology Centre CAS, 370 05 České Budějovice, Czech Republic
| | - Sergio Bordel
- Department of Chemical Engineering and Environmental Technology, School of Industrial Engineering, University of Valladolid, Valladolid 47011, Spain
- Institute of Sustainable Processes, Valladolid 47011, Spain
| | - Lisa Y Stein
- Department of Biological Sciences, Faculty of Science, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Justus Amuche Nweze
- Institute of Soil Biology and Biogeochemistry, Biology Centre CAS, 370 05 České Budějovice, Czech Republic
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czech Republic
- Department of Science Laboratory Technology, Faculty of Physical Sciences, University of Nigeria, Nsukka 410001, Nigeria
| | - Anne Daebeler
- Institute of Soil Biology and Biogeochemistry, Biology Centre CAS, 370 05 České Budějovice, Czech Republic
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Fenibo EO, Selvarajan R, Wang H, Wang Y, Abia ALK. Untapped talents: insight into the ecological significance of methanotrophs and its prospects. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166145. [PMID: 37579801 DOI: 10.1016/j.scitotenv.2023.166145] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/06/2023] [Accepted: 08/06/2023] [Indexed: 08/16/2023]
Abstract
The deep ocean is a rich reservoir of unique organisms with great potential for bioprospecting, ecosystem services, and the discovery of novel materials. These organisms thrive in harsh environments characterized by high hydrostatic pressure, low temperature, and limited nutrients. Hydrothermal vents and cold seeps, prominent features of the deep ocean, provide a habitat for microorganisms involved in the production and filtration of methane, a potent greenhouse gas. Methanotrophs, comprising archaea and bacteria, play a crucial role in these processes. This review examines the intricate relationship between the roles, responses, and niche specialization of methanotrophs in the deep ocean ecosystem. Our findings reveal that different types of methanotrophs dominate specific zones depending on prevailing conditions. Type I methanotrophs thrive in oxygen-rich zones, while Type II methanotrophs display adaptability to diverse conditions. Verrumicrobiota and NC10 flourish in hypoxic and extreme environments. In addition to their essential role in methane regulation, methanotrophs contribute to various ecosystem functions. They participate in the degradation of foreign compounds and play a crucial role in cycling biogeochemical elements like metals, sulfur, and nitrogen. Methanotrophs also serve as a significant energy source for the oceanic food chain and drive chemosynthesis in the deep ocean. Moreover, their presence offers promising prospects for biotechnological applications, including the production of valuable compounds such as polyhydroxyalkanoates, methanobactin, exopolysaccharides, ecotines, methanol, putrescine, and biofuels. In conclusion, this review highlights the multifaceted roles of methanotrophs in the deep ocean ecosystem, underscoring their ecological significance and their potential for advancements in biotechnology. A comprehensive understanding of their niche specialization and responses will contribute to harnessing their full potential in various domains.
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Affiliation(s)
- Emmanuel Oliver Fenibo
- World Bank Africa Centre of Excellence, Centre for Oilfield Chemical Research, University of Port Harcourt, Port Harcourt 500272, Nigeria
| | - Ramganesh Selvarajan
- Laboratory of Extraterrestrial Ocean Systems (LEOS), Institute of Deep-Sea Science and Engineering (IDSSE), Chinese Academy of Sciences (CAS), Sanya, China; Department of Environmental Science, University of South Africa, Florida Campus, 1710, South Africa
| | - Huiqi Wang
- Laboratory of Extraterrestrial Ocean Systems (LEOS), Institute of Deep-Sea Science and Engineering (IDSSE), Chinese Academy of Sciences (CAS), Sanya, China
| | - Yue Wang
- Laboratory of Extraterrestrial Ocean Systems (LEOS), Institute of Deep-Sea Science and Engineering (IDSSE), Chinese Academy of Sciences (CAS), Sanya, China
| | - Akebe Luther King Abia
- Environmental Research Foundation, Westville 3630, South Africa; Antimicrobial Research Unit, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa.
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Houghton KM, Carere CR, Stott MB, McDonald IR. Thermophilic methane oxidation is widespread in Aotearoa-New Zealand geothermal fields. Front Microbiol 2023; 14:1253773. [PMID: 37720161 PMCID: PMC10502179 DOI: 10.3389/fmicb.2023.1253773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 08/16/2023] [Indexed: 09/19/2023] Open
Abstract
Geothermal areas represent substantial point sources for greenhouse gas emissions such as methane. While it is known that methanotrophic microorganisms act as a biofilter, decreasing the efflux of methane in most soils to the atmosphere, the diversity and the extent to which methane is consumed by thermophilic microorganisms in geothermal ecosystems has not been widely explored. To determine the extent of biologically mediated methane oxidation at elevated temperatures, we set up 57 microcosms using soils from 14 Aotearoa-New Zealand geothermal fields and show that moderately thermophilic (>40°C) and thermophilic (>60°C) methane oxidation is common across the region. Methane oxidation was detected in 54% (n = 31) of the geothermal soil microcosms tested at temperatures up to 75°C (pH 1.5-8.1), with oxidation rates ranging from 0.5 to 17.4 μmol g-1 d-1 wet weight. The abundance of known aerobic methanotrophs (up to 60.7% Methylacidiphilum and 11.2% Methylothermus) and putative anaerobic methanotrophs (up to 76.7% Bathyarchaeota) provides some explanation for the rapid rates of methane oxidation observed in microcosms. However, not all methane oxidation was attributable to known taxa; in some methane-consuming microcosms we detected methanotroph taxa in conditions outside of their known temperature range for growth, and in other examples, we observed methane oxidation in the absence of known methanotrophs through 16S rRNA gene sequencing. Both of these observations suggest unidentified methane oxidizing microorganisms or undescribed methanotrophic syntrophic associations may also be present. Subsequent enrichment cultures from microcosms yielded communities not predicted by the original diversity studies and showed rates inconsistent with microcosms (≤24.5 μmol d-1), highlighting difficulties in culturing representative thermophilic methanotrophs. Finally, to determine the active methane oxidation processes, we attempted to elucidate metabolic pathways from two enrichment cultures actively oxidizing methane using metatranscriptomics. The most highly expressed genes in both enrichments (methane monooxygenases, methanol dehydrogenases and PqqA precursor peptides) were related to methanotrophs from Methylococcaceae, Methylocystaceae and Methylothermaceae. This is the first example of using metatranscriptomics to investigate methanotrophs from geothermal environments and gives insight into the metabolic pathways involved in thermophilic methanotrophy.
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Affiliation(s)
- Karen M. Houghton
- Te Pū Ao | GNS Science, Wairakei Research Centre, Taupō, New Zealand
- Te Aka Mātuatua | School of Science, Te Whare Wānanga o Waikato | University of Waikato, Hamilton, New Zealand
| | - Carlo R. Carere
- Te Pū Ao | GNS Science, Wairakei Research Centre, Taupō, New Zealand
- Te Tari Pūhanga Tukanga Matū | Department of Chemical and Process Engineering, Te Whare Wānanga o Waitaha | University of Canterbury, Christchurch, New Zealand
| | - Matthew B. Stott
- Te Pū Ao | GNS Science, Wairakei Research Centre, Taupō, New Zealand
- Te Kura Pūtaiao Koiora | School of Biological Sciences, Te Whare Wānanga o Waitaha | University of Canterbury, Christchurch, New Zealand
| | - Ian R. McDonald
- Te Aka Mātuatua | School of Science, Te Whare Wānanga o Waikato | University of Waikato, Hamilton, New Zealand
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Soleimanifar M, Rodriguez-Freire L. Biointeraction of cerium oxide and neodymium oxide nanoparticles with pure culture methylobacterium extorquens AM1. CHEMOSPHERE 2023:139113. [PMID: 37270036 DOI: 10.1016/j.chemosphere.2023.139113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 06/05/2023]
Abstract
Rare earth elements (REE) are valuable raw materials in our modern life. Extensive REE application from electronic devices to medical instruments and wind turbines, and non-uniform distribution of these resources around the world, make them strategically and economically important for countries. Current REE physical and chemical mining and recycling methods could have negative environmental consequences, and biologically-mediated techniques could be applied to overcome this issue. In this study, the bioextraction of cerium oxide and neodymium oxide nanoparticles (REE-NP) by a pure culture Methylobacterium extorquens AM1 (ATCC®14718™) was investigated in batch experiments. Results show that adding up to 1000 ppm CeO2 or Nd2O3 nanoparticles (REE-NP) did not seem to affect the bacterial growth over 14-days contact time. Effect of methylamine hydrochloride as an essential electron donor and carbon source for microbial oxidation and growth was also observed inasmuch as there was approximately no growth when it does not exist in the medium. Although very low concentrations of cerium and neodymium in the liquid phase were measured, concentrations of 45 μg/gcell Ce and 154 μg/gcell Nd could be extracted by M. extorquens AM1. Furthermore, SEM-EDS and STEM-EDS confirmed surface and intracellular accumulation of nanoparticles. These results confirmed the ability of M. extorquens to accumulate REE nanoparticles.
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Affiliation(s)
- Maedeh Soleimanifar
- John A. Reif, Jr. Department of Civil & Environmental Engineering, New Jersey Institute of Technology, 07102, Newark, NJ, United States.
| | - Lucia Rodriguez-Freire
- John A. Reif, Jr. Department of Civil & Environmental Engineering, New Jersey Institute of Technology, 07102, Newark, NJ, United States
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Xie R, Takashino M, Igarashi K, Kitagawa W, Kato S. Transcriptional Regulation of Methanol Dehydrogenases in the Methanotrophic Bacterium Methylococcus capsulatus Bath by Soluble and Insoluble Lanthanides. Microbes Environ 2023; 38:ME23065. [PMID: 38092408 PMCID: PMC10728633 DOI: 10.1264/jsme2.me23065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 10/18/2023] [Indexed: 12/18/2023] Open
Abstract
The effects of soluble and insoluble lanthanides on gene expression in Methylococcus capsulatus Bath were investigated. Genes for lanthanide-containing methanol dehydrogenases (XoxF-MDHs) and their calcium-containing counterparts (MxaFI-MDHs) were up- and down-regulated, respectively, by supplementation with soluble lanthanide chlorides, indicating that M. capsulatus has the "lanthanide switch" observed in other methanotrophs. Insoluble lanthanide oxides also induced the lanthanide switch and were dissolved by the spent medium of M. capsulatus, suggesting the presence of lanthanide-chelating compounds. A transcriptome ana-lysis indicated that a gene cluster for the synthesis of an enterobactin-like metal chelator contributed to the dissolution of insoluble lanthanides.
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Affiliation(s)
- Ruoyun Xie
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo 060–8589, Japan
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, 2–17–2–1 Tsukisamu-Higashi, Toyohira-ku, Sapporo 062–8517, Japan
| | - Motoko Takashino
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, 2–17–2–1 Tsukisamu-Higashi, Toyohira-ku, Sapporo 062–8517, Japan
| | - Kensuke Igarashi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, 2–17–2–1 Tsukisamu-Higashi, Toyohira-ku, Sapporo 062–8517, Japan
| | - Wataru Kitagawa
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo 060–8589, Japan
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, 2–17–2–1 Tsukisamu-Higashi, Toyohira-ku, Sapporo 062–8517, Japan
| | - Souichiro Kato
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo 060–8589, Japan
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, 2–17–2–1 Tsukisamu-Higashi, Toyohira-ku, Sapporo 062–8517, Japan
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8
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Crombie AT. The effect of lanthanum on growth and gene expression in a facultative methanotroph. Environ Microbiol 2021; 24:596-613. [PMID: 34320271 PMCID: PMC9291206 DOI: 10.1111/1462-2920.15685] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 07/25/2021] [Indexed: 11/29/2022]
Abstract
The biological importance of lanthanides has only recently been identified, initially as the active site metal of the alternative methanol dehydrogenase (MDH) Xox‐MDH. So far, the effect of lanthanide (Ln) has only been studied in relatively few organisms. This work investigated the effects of Ln on gene transcription and protein expression in the facultative methanotroph Methylocella silvestris BL2, a widely distributed methane‐oxidizing bacterium with the unique ability to grow not just on methane but also on other typical components of natural gas, ethane and propane. Expression of calcium‐ or Ln‐dependent MDH was controlled by Ln (the lanthanide switch) during growth on one‐, two‐ or three‐carbon substrates, and Ln imparted a considerable advantage during growth on propane, a novel result extending the importance of Ln to consumers of this component of natural gas. Two Xox‐MDHs were expressed and regulated by Ln in M. silvestris, but interestingly Ln repressed rather than induced expression of the second Xox‐MDH. Despite the metabolic versatility of M. silvestris, no other alcohol dehydrogenases were expressed, and in double‐mutant strains lacking genes encoding both Ca‐ and Ln‐dependent MDHs (mxaF and xoxF5 or xoxF1), growth on methanol and ethanol appeared to be enabled by expression of the soluble methane monooxygenase.
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Affiliation(s)
- Andrew T Crombie
- School of Biological Science, University of East Anglia, Norwich, NR4 7TJ, UK.,School of Environmental Science, University of East Anglia, Norwich, NR4 7TJ, UK
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Vu HN, Subuyuj GA, Crisostomo RV, Skovran E. Transposon mutagenesis for methylotrophic bacteria using Methylorubrum extorquens AM1 as a model system. Methods Enzymol 2021; 650:159-184. [PMID: 33867020 DOI: 10.1016/bs.mie.2021.01.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Transposon mutagenesis utilizes transposable genetic elements that integrate into a recipient genome to generate random insertion mutations which are easily identified. This forward genetic approach has proven powerful in elucidating complex processes, such as various pathways in methylotrophy. In the past decade, many methylotrophic bacteria have been shown to possess alcohol dehydrogenase enzymes that use lanthanides (Lns) as cofactors. Using Methylorubrum extorquens AM1 as a model organism, we discuss the experimental designs, protocols, and results of three transposon mutagenesis studies to identify genes involved in different aspects of Ln-dependent methanol oxidation. These studies include a selection for transposon insertions that prevent toxic intracellular formaldehyde accumulation, a fluorescence-imaging screen to identify regulatory processes for a primary Ln-dependent methanol dehydrogenase, and a phenotypic screen for genes necessary for function of a Ln-dependent ethanol dehydrogenase. We anticipate that the methods described in this chapter can be applied to understand other metabolic systems in diverse bacteria.
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Affiliation(s)
- Huong N Vu
- Department of Biological Sciences, San José State University, San José, CA, United States
| | - Gabriel A Subuyuj
- Department of Biological Sciences, San José State University, San José, CA, United States
| | | | - Elizabeth Skovran
- Department of Biological Sciences, San José State University, San José, CA, United States.
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Discovery of lanthanide-dependent methylotrophy and screening methods for lanthanide-dependent methylotrophs. Methods Enzymol 2021; 650:1-18. [PMID: 33867018 DOI: 10.1016/bs.mie.2021.01.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The lanthanide elements (Lns) affect the physiology and growth of certain microorganisms known as "Ln-responsive microorganisms." Among them, in 2011, it was first reported that strains of Methylobacterium exhibited high methanol dehydrogenase (MDH) activity when grown in the presence of Lns; the purified Ln-inducible MDH was identified as XoxF-type MDH, whose catalytic function had previously been unknown. XoxF was the first enzyme to be identified as Ln-dependent, and its function in methylotrophy is more fundamental and important than that of the corresponding Ca2+-dependent MDH MxaFI. XoxF is encoded in the genomes of methylotrophic as well as non-methylotrophic bacteria. Thus, Lns are among the most fascinating and important growth factors for bacteria that potentially utilize methanol. Bacteria that require Lns for methanol growth are called "Ln-dependent methylotrophs." Recent findings indicate that these microorganisms comprise an "Ln-dependent ecosystem" that we have not been able to reconstruct under laboratory conditions without Lns. In this chapter, we summarize methods for (1) screening of Ln-responsive microorganisms, (2) purification of native XoxFs from Ln-dependent methylotrophs, and (3) screening of Ln-dependent methylotrophs from natural environments, while providing a history of the discovery of the Ln-dependent methylotrophs.
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Schmitz RA, Peeters SH, Versantvoort W, Picone N, Pol A, Jetten MSM, Op den Camp HJM. Verrucomicrobial methanotrophs: ecophysiology of metabolically versatile acidophiles. FEMS Microbiol Rev 2021; 45:6125968. [PMID: 33524112 PMCID: PMC8498564 DOI: 10.1093/femsre/fuab007] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/15/2021] [Indexed: 12/26/2022] Open
Abstract
Methanotrophs are an important group of microorganisms that counteract methane emissions to the atmosphere. Methane-oxidising bacteria of the Alpha- and Gammaproteobacteria have been studied for over a century, while methanotrophs of the phylum Verrucomicrobia are a more recent discovery. Verrucomicrobial methanotrophs are extremophiles that live in very acidic geothermal ecosystems. Currently, more than a dozen strains have been isolated, belonging to the genera Methylacidiphilum and Methylacidimicrobium. Initially, these methanotrophs were thought to be metabolically confined. However, genomic analyses and physiological and biochemical experiments over the past years revealed that verrucomicrobial methanotrophs, as well as proteobacterial methanotrophs, are much more metabolically versatile than previously assumed. Several inorganic gases and other molecules present in acidic geothermal ecosystems can be utilised, such as methane, hydrogen gas, carbon dioxide, ammonium, nitrogen gas and perhaps also hydrogen sulfide. Verrucomicrobial methanotrophs could therefore represent key players in multiple volcanic nutrient cycles and in the mitigation of greenhouse gas emissions from geothermal ecosystems. Here, we summarise the current knowledge on verrucomicrobial methanotrophs with respect to their metabolic versatility and discuss the factors that determine their diversity in their natural environment. In addition, key metabolic, morphological and ecological characteristics of verrucomicrobial and proteobacterial methanotrophs are reviewed.
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Affiliation(s)
- Rob A Schmitz
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Stijn H Peeters
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Wouter Versantvoort
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Nunzia Picone
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Arjan Pol
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
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12
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Igarashi K, Kato S. Reductive Transformation of Fe(III) (oxyhydr)Oxides by Mesophilic Homoacetogens in the Genus Sporomusa. Front Microbiol 2021; 12:600808. [PMID: 33633701 PMCID: PMC7901989 DOI: 10.3389/fmicb.2021.600808] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/04/2021] [Indexed: 01/10/2023] Open
Abstract
Microbial reduction of iron contributes to the dissolution and transformation of iron-containing minerals in nature. Diverse groups of homoacetogenic bacteria (homoacetogens) have been reported to reduce insoluble Fe(III) oxides, such as hydrous ferric oxide (HFO), an Fe(III) mineral commonly found in soils and sediments. Several members of genus Sporomusa reportedly oxidize Fe(0), indicating the presence of an extracellular electron-uptake mechanism. However, the ability of the genus to reduce insoluble Fe(III) oxides is limited, and the underlying reduction mechanism remains to be elucidated. In this study, the HFO reduction ability of three Sporomusa spp. (Sporomusa sp. strain GT1, Sporomusa sphaeroides, and Sporomusa ovata) and a homoacetogen of a different genus (Acetobacterium woodii) were assayed under organotrophic (ethanol) and lithotrophic (H2 + CO2) conditions without a chelator or reducing reagent. All tested homoacetogens showed acetogenic growth and concomitant reduction of HFO under both organotrophic and lithotrophic conditions. Analysis of the growth stoichiometry showed that Fe(III) reduction does not support direct energy conservation, thereby indicating that Fe(III) reduction is a side reaction of acetogenesis to dissipate the excess reducing power. HFO was reduced to a soluble Fe(II) form by microbial activity. In addition, we observed that strain GT1, S. sphaeroides, and S. ovata reduced crystalline Fe(III) oxides, and HFO was reductively transformed into magnetite (Fe3O4) under phosphate-limiting conditions. Separation of HFO by a dialysis membrane still permitted Fe(II) production, although the reduction rate was decreased, suggesting that Fe(III) reduction is at least partially mediated by soluble redox compound(s) secreted from the cells. Finally, culture experiments and comparative genomic analysis suggested that electron transfer by flavins and multiheme c-type cytochrome were not directly correlated with Fe(III) reduction activity. This study reveals the capability of Sporomusa spp. in the reductive transformation of iron mineral and indicates the potential involvement of these organisms in iron and other mineral cycles in nature.
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Affiliation(s)
- Kensuke Igarashi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan
| | - Souichiro Kato
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan.,Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan
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Farhan Ul Haque M, Xu HJ, Murrell JC, Crombie A. Facultative methanotrophs - diversity, genetics, molecular ecology and biotechnological potential: a mini-review. MICROBIOLOGY (READING, ENGLAND) 2020; 166:894-908. [PMID: 33085587 PMCID: PMC7660913 DOI: 10.1099/mic.0.000977] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/20/2020] [Indexed: 12/18/2022]
Abstract
Methane-oxidizing bacteria (methanotrophs) play a vital role in reducing atmospheric methane emissions, and hence mitigating their potent global warming effects. A significant proportion of the methane released is thermogenic natural gas, containing associated short-chain alkanes as well as methane. It was one hundred years following the description of methanotrophs that facultative strains were discovered and validly described. These can use some multi-carbon compounds in addition to methane, often small organic acids, such as acetate, or ethanol, although Methylocella strains can also use short-chain alkanes, presumably deriving a competitive advantage from this metabolic versatility. Here, we review the diversity and molecular ecology of facultative methanotrophs. We discuss the genetic potential of the known strains and outline the consequent benefits they may obtain. Finally, we review the biotechnological promise of these fascinating microbes.
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Affiliation(s)
| | - Hui-Juan Xu
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
- Present address: Joint Institute for Environmental Research & Education, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, PR China
| | - J. Colin Murrell
- School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Andrew Crombie
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
- Present address: School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
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Meruvu H, Wu H, Jiao Z, Wang L, Fei Q. From nature to nurture: Essence and methods to isolate robust methanotrophic bacteria. Synth Syst Biotechnol 2020; 5:173-178. [PMID: 32637670 PMCID: PMC7327766 DOI: 10.1016/j.synbio.2020.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/03/2020] [Accepted: 06/18/2020] [Indexed: 02/07/2023] Open
Abstract
Methanotrophic bacteria are entities with innate biocatalytic potential to biofilter and oxidize methane into simpler compounds concomitantly conserving energy, which can contribute to copious industrial applications. The future and efficacy of such industrial applications relies upon acquiring and/or securing robust methanotrophs with taxonomic and phenotypic diversity. Despite several dramatic advances, isolation of robust methanotrophs is still a long-way challenging task with several lacunae to be filled in sequentially. Methanotrophs with high tolerance to methane can be isolated and cultivated by mimicking natural environs, and adopting strategies like adaptive metabolic evolution. This review summarizes existent and innovative methods for methanotrophic isolation and purification, and their respective applications. A comprehensive description of new insights shedding light upon how to isolate and concomitantly augment robust methanotrophic metabolism in an orchestrated fashion follows.
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Affiliation(s)
- Haritha Meruvu
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Hui Wu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Ziyue Jiao
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Liyan Wang
- Luoyang TMAXTREE Biotechnology Co., Ltd., Luoyang, China
| | - Qiang Fei
- School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, China
- Shaanxi Key Laboratory of Energy Chemical Process Intensification, Xi'an Jiaotong University, Xi'an, China
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Pastawan V, Agus Fitriyanto N, Nakagawa T. Biological Function of Lanthanide in Plant-Symbiotic Bacteria: Lanthanide-Dependent Methanol Oxidation System. ACTA ACUST UNITED AC 2020. [DOI: 10.7831/ras.8.0_186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Viagian Pastawan
- The United Graduate School of Agricultural Science, Gifu University, Tokai National Higher Education, Research System, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Nanung Agus Fitriyanto
- Faculty of Animal Science, Universitas Gadjah Mada, Jl. Fauna No. 3 Bulaksumur, Yogyakarta 55281, Indonesia
| | - Tomoyuki Nakagawa
- The United Graduate School of Agricultural Science, Gifu University, Tokai National Higher Education, Research System, 1-1 Yanagido, Gifu 501-1193, Japan
- Faculty of Applied Biological Sciences, Gifu University, Tokai National Higher Education, Research System, 1-1 Yanagido, Gifu 501-1193, Japan
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