Faculty Opinions recommendation of Two isozymes of particulate methane monooxygenase with different methane oxidation kinetics are found in Methylocystis sp. strain SC2.

2008 ◽  
Author(s):  
Amy Rosenzweig
Keyword(s):  
Methane Oxidation ◽  
Oxidation Kinetics ◽  
Methane Monooxygenase ◽  
Particulate Methane Monooxygenase

scholarly journals Lake mixing regime selects methane-oxidation kinetics of the methanotroph assemblage

2020 ◽  
Author(s):  
Magdalena J. Mayr ◽  
Matthias Zimmermann ◽  
Jason Dey ◽  
Bernhard Wehrli ◽  
Helmut Bürgmann
Keyword(s):  
Methane Oxidation ◽  
Oxidation Kinetics ◽  
Methane Monooxygenase ◽  
Stable Stratification ◽  
Stratified Lakes ◽  
Methane Oxidizing Bacteria ◽  
Half Saturation Constant ◽  
Genes Encoding ◽  
Natural Microbial Community ◽  
Methane Concentrations

Abstract. In freshwater lakes, large amounts of methane are produced in anoxic sediments. Methane-oxidizing bacteria effectively convert this potent greenhouse gas into biomass and carbon dioxide. These bacteria are present throughout the water column where methane concentrations can range from nanomolar to millimolar concentrations. In this study, we tested the hypothesis that methanotroph assemblages in seasonally stratified lakes are adapted to the contrasting methane concentrations in the epi- and hypolimnion. We further hypothesized that lake overturn would change the methane oxidation kinetics as more methane becomes available in the epilimnion. Together with the change of methane oxidation kinetics, we investigated changes in the transcription of genes encoding methane monooxygenase, the enzyme responsible for the first step of methane oxidation, with metatranscriptomics. We show that the half-saturation constant (Km) for methane, obtained from laboratory experiments with the natural microbial community, differed by two orders of magnitude between epi- and hypolimnion during stable stratification. During lake overturn, however, the kinetic constants in the epi- and hypolimnion converged along with a change of the transcriptionally active methanotroph assemblage. Conventional particulate methane monooxygenase appeared to be responsible for methane oxidation under different methane concentrations. Our results suggest that methane availability is important for creating niches for methanotroph assemblages with well-adapted methane-oxidation kinetics. This rapid selection and succession of adapted lacustrine methanotroph assemblages allows high methane removal efficiency of more than 90 % to be maintained even under rapidly changing conditions during lake overturn. Consequently, only a small fraction of methane stored in the anoxic hypolimnion is emitted to the atmosphere.

Catalytic machinery of methane oxidation in particulate methane monooxygenase (pMMO)

2021 ◽  
Vol 225 ◽  
pp. 111602
Author(s):  
Sunney I. Chan ◽  
Wei-Hau Chang ◽  
Shih-Hsin Huang ◽  
Hsin-Hung Lin ◽  
Steve S.-F. Yu
Keyword(s):  
Methane Oxidation ◽  
Methane Monooxygenase ◽  
Particulate Methane Monooxygenase

Turnover of a Methane Oxidation Tricopper Cluster Catalyst: Implications for the Mechanism of the Particulate Methane Monooxygenase (pMMO)

ChemCatChem ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3088-3096
Author(s):  
Yu‐Hsuan Chen ◽  
Chang‐Quan Wu ◽  
Pei‐Hua Sung ◽  
Sunney I. Chan ◽  
Peter Ping‐Yu Chen
Keyword(s):  
Methane Oxidation ◽  
Methane Monooxygenase ◽  
Particulate Methane Monooxygenase

scholarly journals Particulate methane monooxygenase contains only mononuclear copper centers

Science ◽  
2019 ◽  
Vol 364 (6440) ◽  
pp. 566-570 ◽  
Author(s):  
Matthew O. Ross ◽  
Fraser MacMillan ◽  
Jingzhou Wang ◽  
Alex Nisthal ◽  
Thomas J. Lawton ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Methane Oxidation ◽  
Active Site ◽  
Methane Monooxygenase ◽  
Spectroscopic Characterization ◽  
Metabolic Enzyme ◽  
Particulate Methane Monooxygenase ◽  
Paramagnetic Resonance ◽  
Membrane Bound ◽  
Electron Paramagnetic

Bacteria that oxidize methane to methanol are central to mitigating emissions of methane, a potent greenhouse gas. The nature of the copper active site in the primary metabolic enzyme of these bacteria, particulate methane monooxygenase (pMMO), has been controversial owing to seemingly contradictory biochemical, spectroscopic, and crystallographic results. We present biochemical and electron paramagnetic resonance spectroscopic characterization most consistent with two monocopper sites within pMMO: one in the soluble PmoB subunit at the previously assigned active site (CuB) and one ~2 nanometers away in the membrane-bound PmoC subunit (CuC). On the basis of these results, we propose that a monocopper site is able to catalyze methane oxidation in pMMO.

scholarly journals Lake mixing regime selects apparent methane oxidation kinetics of the methanotroph assemblage

2020 ◽  
Vol 17 (16) ◽  
pp. 4247-4259
Author(s):  
Magdalena J. Mayr ◽  
Matthias Zimmermann ◽  
Jason Dey ◽  
Bernhard Wehrli ◽  
Helmut Bürgmann
Keyword(s):  
Methane Oxidation ◽  
Oxidation Kinetics ◽  
Methane Monooxygenase ◽  
Stable Stratification ◽  
Methane Oxidizing Bacteria ◽  
Half Saturation Constant ◽  
Genes Encoding ◽  
Methane Oxidation Rate ◽  
Kinetics Of ◽  
Methane Concentrations

Abstract. In lakes, large amounts of methane are produced in anoxic sediments. Methane-oxidizing bacteria effectively convert this potent greenhouse gas into biomass and carbon dioxide. These bacteria are present throughout the water column, where methane concentrations can range from nanomolar to millimolar. In this study, we tested the hypothesis that methanotroph assemblages in a seasonally stratified freshwater lake are adapted to the contrasting methane concentrations in the epi- and hypolimnion. We further hypothesized that lake overturn would change the apparent methane oxidation kinetics as more methane becomes available in the epilimnion. In addition to the change in the methane oxidation kinetics, we investigated changes in the transcription of genes encoding methane monooxygenase, the enzyme responsible for the first step of methane oxidation, with metatranscriptomics. Using laboratory incubations of the natural microbial communities, we show that the half-saturation constant (Km) for methane – the methane concentration at which half the maximum methane oxidation rate is reached – was 20 times higher in the hypolimnion than in the epilimnion during stable stratification. During lake overturn, however, the kinetic constants in the epi- and hypolimnion converged along with a change in the transcriptionally active methanotroph assemblage. Conventional particulate methane monooxygenase appeared to be responsible for methane oxidation under different methane concentrations. Our results suggest that methane availability is one important factor for creating niches for methanotroph assemblages with well-adapted methane oxidation kinetics. This rapid selection and succession of adapted lacustrine methanotroph assemblages allowed the previously reported high removal efficiency of methane transported to the epilimnion to be maintained – even under rapidly changing conditions during lake overturn. Consequently, only a small fraction of methane stored in the anoxic hypolimnion is emitted to the atmosphere.

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