Particulate Methane Monooxygenase

Rosenzweig, Amy C.

doi:10.1002/0470028637.met232

Cited by 3 publications

(2 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Inspired by the naturally occurring particulate methane monooxygenases (pMMO), − copper-exchanged zeolites have been developed as selective methane to methanol catalysts following a three-stage process that uses air as oxidant. Multiple zeolite topologies have been shown to accommodate active cationic Cu-oxo clusters for the transformation, among which mordenite (MOR) is arguably the most widely studied zeolite.…”

Section: Introductionmentioning

confidence: 99%

Speciation and Reactivity Control of Cu-Oxo Clusters via Extraframework Al in Mordenite for Methane Oxidation

et al. 2023

View full text Add to dashboard Cite

The stoichiometric conversion of methane to methanol by Cu-exchanged zeolites can be brought to highest yields by the presence of extraframework Al and high CH4 chemical potentials. Combining theory and experiments, the differences in chemical reactivity of monometallic Cu-oxo and bimetallic Cu-Al-oxo nanoclusters stabilized in zeolite mordenite (MOR) are investigated. Cu-L3 edge X-ray absorption near-edge structure (XANES), infrared (IR), and ultraviolet–visible (UV–vis) spectroscopies, in combination with CH4 oxidation activity tests, support the presence of two types of active clusters in MOR and allow quantification of the relative proportions of each type in dependence of the Cu concentration. Ab initio molecular dynamics (MD) calculations and thermodynamic analyses indicate that the superior performance of materials enriched in Cu-Al-oxo clusters is related to the activity of two μ-oxo bridges in the cluster. Replacing H2O with ethanol in the product extraction step led to the formation of ethyl methyl ether, expanding this way the applicability of these materials for the activation and functionalization of CH4. We show that competition between different ion-exchanged metal-oxo structures during the synthesis of Cu-exchanged zeolites determines the formation of active species, and this provides guidelines for the synthesis of highly active materials for CH4 activation and functionalization.

show abstract

Section: Introductionmentioning

confidence: 99%

Speciation and Reactivity Control of Cu-Oxo Clusters via Extraframework Al in Mordenite for Methane Oxidation

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Methane is oxidized primarily by particulate methane monooxygenase (pMMO), encoded by the pmo genes (Hanson and Thomas, 1996; Hakemian and Rosenzweig, 2007; Rosenzweig, 2011) although soluble methane monooygenase (sMMO) has been shown to be functional in a few instances (Hakemian and Rosenzweig, 2007). Propane (pMO) and butane monooxygenases (bMO) have both been identified in microorganisms that can metabolize short chain alkanes (Sluis et al, 2002; Arp et al, 2007; Cooley et al, 2009; Redmond et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Identity and mechanisms of alkane-oxidizing metalloenzymes from deep-sea hydrothermal vents

Bertrand¹,

Keddis²,

Groves³

et al. 2013

Front. Microbiol.

View full text Add to dashboard Cite

Six aerobic alkanotrophs (organism that can metabolize alkanes as their sole carbon source) isolated from deep-sea hydrothermal vents were characterized using the radical clock substrate norcarane to determine the metalloenzyme and reaction mechanism used to oxidize alkanes. The organisms studied were Alcanivorax sp. strains EPR7 and MAR14, Marinobacter sp. strain EPR21, Nocardioides sp. strains EPR26w, EPR28w, and Parvibaculum hydrocarbonoclasticum strain EPR92. Each organism was able to grow on n-alkanes as the sole carbon source and therefore must express genes encoding an alkane-oxidizing enzyme. Results from the oxidation of the radical-clock diagnostic substrate norcarane demonstrated that five of the six organisms (EPR7, MAR14, EPR21, EPR26w, and EPR28w) used an alkane hydroxylase functionally similar to AlkB to catalyze the oxidation of medium-chain alkanes, while the sixth organism (EPR92) used an alkane-oxidizing cytochrome P450 (CYP)-like protein to catalyze the oxidation. DNA sequencing indicated that EPR7 and EPR21 possess genes encoding AlkB proteins, while sequencing results from EPR92 confirmed the presence of a gene encoding CYP-like alkane hydroxylase, consistent with the results from the norcarane experiments.

show abstract

Metabolic Regulation of “Ca. Methylacidiphilum Fumariolicum” SolV Cells Grown Under Different Nitrogen and Oxygen Limitations

Khadem¹,

Pol²,

Wieczorek³

et al. 2012

Front. Microbio.

View full text Add to dashboard Cite

Aerobic methanotrophic bacteria can use methane as their sole energy source. The discovery of “Ca. Methylacidiphilum fumariolicum” strain SolV and other verrucomicrobial methanotrophs has revealed that the ability of bacteria to oxidize CH4 is much more diverse than has previously been assumed in terms of ecology, phylogeny, and physiology. A remarkable characteristic of the methane-oxidizing Verrucomicrobia is their extremely acidophilic phenotype, growing even below pH 1. In this study we used RNA-Seq to analyze the metabolic regulation of “Ca. M. fumariolicum” SolV cells growing at μmax in batch culture or under nitrogen fixing or oxygen limited conditions in chemostats, all at pH 2. The analysis showed that two of the three pmoCAB operons each encoding particulate methane monoxygenases were differentially expressed, probably regulated by the available oxygen. The hydrogen produced during N2 fixation is apparently recycled as demonstrated by the upregulation of the genes encoding a Ni/Fe-dependent hydrogenase. These hydrogenase genes were also upregulated under low oxygen conditions. Handling of nitrosative stress was shown by the expression of the nitric oxide reductase encoding genes norB and norC under all conditions tested, the upregulation of nitrite reductase nirK under oxygen limitation and of hydroxylamine oxidoreductase hao in the presence of ammonium. Unraveling the gene regulation of carbon and nitrogen metabolism helps to understand the underlying physiological adaptations of strain SolV in view of the harsh conditions of its natural ecosystem.

show abstract

Particulate Methane Monooxygenase

Cited by 3 publications

References 67 publications

Speciation and Reactivity Control of Cu-Oxo Clusters via Extraframework Al in Mordenite for Methane Oxidation

Speciation and Reactivity Control of Cu-Oxo Clusters via Extraframework Al in Mordenite for Methane Oxidation

Identity and mechanisms of alkane-oxidizing metalloenzymes from deep-sea hydrothermal vents

Metabolic Regulation of “Ca. Methylacidiphilum Fumariolicum” SolV Cells Grown Under Different Nitrogen and Oxygen Limitations

Contact Info

Product

Resources

About