Role of copper and iron in methane oxidation and bacterial biopolymer accumulation

Chidambarampadmavathy, Karthigeyan; Obulisamy, Parthiba Karthikeyan; Heimann, Kirsten

doi:10.1002/elsc.201400127

Cited by 28 publications

(14 citation statements)

References 121 publications

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“…Prior research has shown that the expression of MMOs is regulated by Cu 2+ . To be more accurate, the expression of sMMO is efficient at less than 0.8 μM Cu 2+ and is restricted at an excess of 4 μM of Cu 2+ in methanotrophs .…”

Section: Resultsmentioning

confidence: 99%

“…Based on the expression of pmoA and mmoX, the quantity of pmoA was 1 to 4 orders of magnitude greater than that of mmoX, indicating that pMMO likely plays a more prominent role than sMMO under these conditions. Prior research has shown that the expression of MMOs is regulated by Cu 2+ [13,16,17]. To be more accurate, the expression of sMMO is efficient at less than 0.8 μM Cu 2+ and is restricted at an excess of 4 μM of Cu 2+ in methanotrophs [38].…”

Section: Expression Of Pmoa and Mmox At Different Cu 2+ Concentrationsmentioning

confidence: 99%

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Effects of copper on expression of methane monooxygenases, trichloroethylene degradation, and community structure in methanotrophic consortia

Xing

Zhao

Zhang

et al. 2018

Engineering in Life Sciences

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Copper plays a key role in regulating the expression of enzymes that promote biodegradation of contaminants in methanotrophic consortia (MC). Here, we utilized MC isolated from landfill cover to investigate cometabolic degradation of trichloroethylene (TCE) at nine different copper (Cu2+) concentrations. The results demonstrated that an increase in Cu2+ concentration from 0 to 15 μM altered the specific first‐order rate constant k1,TCE, the expression levels of methane monooxygenase (pmoA and mmoX) genes, and the specific activity of soluble methane monooxygenase (sMMO). High efficiency TCE degradation (95%) and the expression levels of methane monooxygenase (MMO) were detected at a Cu2+ concentration of 0.03 μM. Notably, sMMO‐specific activity ranged from 74.41 nmol/(mgcell h) in 15 μM Cu2+ to 654.99 nmol/(mgcell h) in 0.03 μM Cu2+, which contrasts with cultures of pure methanotrophs in which sMMO activity is depressed at high Cu2+ concentrations, indicating a special regulatory role for Cu2+ in MC. The results of MiSeq pyrosequencing indicated that higher Cu2+ concentrations stimulated the growth of methanotrophic microorganisms in MC. These findings have important implications for the elucidation of copper‐mediated regulatory mechanisms in MC.

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Section: Resultsmentioning

confidence: 99%

Section: Expression Of Pmoa and Mmox At Different Cu 2+ Concentrationsmentioning

confidence: 99%

Effects of copper on expression of methane monooxygenases, trichloroethylene degradation, and community structure in methanotrophic consortia

Xing

Zhao

Zhang

et al. 2018

Engineering in Life Sciences

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“…Recent attention has been paid to the optimization of PHB accumulation from a microbiological point of view by identifying the key limiting macro/micronutrients that boost PHB synthesis in methanotrophs. However, to the best of the authors' knowledge, the influence of micronutrients such as Mn, Fe, and K on methanotrophic PHB synthesis has been scarcely studied [18,19]. Moreover, few studies have evaluated the simultaneous abatement of dilute CH 4 emissions and co-production of PHB in gas-phase bioreactors under continuous operation [20].…”

Section: Introductionmentioning

confidence: 99%

Simultaneous methane abatement and PHB production by Methylocystis hirsuta in a novel gas-recycling bubble column bioreactor

García-Pérez

López

Passos

et al. 2018

Chemical Engineering Journal

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The limited gas-liquid mass transfer represents the main challenge in the operation of costeffective bioreactors devoted to the treatment of poorly soluble gas pollutants such as methane (CH 4). This study evaluates the influence of internal gas-recycling strategies on the enhancement of CH 4 abatement in a bubble column bioreactor inoculated with the methanotroph Methylocystis hirsuta. Maximum CH 4 removal efficiencies of 72.9 ± 0.5 % (corresponding to elimination capacities of 35.2 ± 0.4 g m-3 h-1) were recorded under process operation at an empty bed residence time of 30 min and 0.50 m 3 gas m-3 reactor min-1 of internal gas-recycling rate. The accumulation of poly-3-hydroxybutyrate (PHB) in M. hirsuta was evaluated batchwise under limitations of potassium, manganese, nitrogen, and nitrogen with excess of iron. Nitrogen starvation resulted in the highest PHB content (28 ± 1 %). Likewise, the implementation of sequential N starvation cycles in a continuous bubble column reactor operated at a gas residence time of 30 min and an internal gasrecycling rate of 0.50 m 3 gas m-3 reactor min-1 supported a PHB content of up to 34.6 ± 2.5 %, with a volumetric PHB productivity of 1.4 ± 0.4 kg m-3 d-1 and elimination capacities of 16.2 ± 9.5 g m-3 h-1 .

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“…Numerous microelements have been established or are newly emerging as control points for primary methane oxidation ( Glass and Orphan, 2012 ; Chidambarampadmavathy et al, 2015 ; Semrau et al, 2018 ). Three key metabolic switches have been described: (1) a copper-switch, which controls the expression and activity of primary methane oxidation ( Stanley et al, 1983 ; Semrau et al, 2018 ); (2) a tungsten-molybdenum (W/Mo) switch for formate oxidation ( Laukel et al, 2003 ; Chistoserdova et al, 2004 ; Akberdin et al, 2018 ); and (3) a La-switch, which negatively regulates the expression of MxaFI-MeDH and activates XoxF-MeDH ( Haque et al, 2015 ; Chu and Lidstrom, 2016 ; Chu et al, 2016 ; Gu and Semrau, 2017 ; Semrau et al, 2018 ).…”

Section: Introductionmentioning

confidence: 99%

Rare Earth Elements Alter Redox Balance in Methylomicrobium alcaliphilum 20ZR

et al. 2018

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Background: Rare Earth Elements (REEs) control methanol utilization in both methane- and methanol-utilizing microbes. It has been established that the addition of REEs leads to the transcriptional repression of MxaFI-MeDH [a two-subunit methanol dehydrogenase (MeDH), calcium-dependent] and the activation of XoxF-MeDH (a one-subunit MeDH, lanthanum-dependent). Both enzymes are pyrroquinoline quinone-dependent alcohol dehydrogenases and show significant homology; however, they display different kinetic properties and substrate specificities. This study investigates the impact of the MxaFI to XoxF switch on the behavior of metabolic networks at a global scale.Results: In this study we investigated the steady-state growth of Methylomicrobium alcaliphilum 20ZR in media containing calcium (Ca) or lanthanum (La, a REE element). We found that cells supplemented with La show a higher growth rate compared to Ca-cultures; however, the efficiency of carbon conversion, estimated as biomass yield, is higher in cells grown with Ca. Three complementary global-omics approaches–RNA-seq transcriptomics, proteomics, and metabolomics–were applied to investigate the mechanisms of improved growth vs. carbon conversion. Cells grown with La showed the transcriptional activation of the xoxF gene, a homolog of the formaldehyde-activating enzyme (fae2), a putative transporter, genes for hemin-transport proteins, and nitrate reductase. In contrast, genes for mxaFI and associated cytochrome (mxaG) expression were downregulated. Proteomic profiling suggested additional adjustments of the metabolic network at the protein level, including carbon assimilation pathways, electron transport systems, and the tricarboxylic acid (TCA) cycle. Discord between gene expression and protein abundance changes points toward the possibility of post-transcriptional control of the related systems including key enzymes of the TCA cycle and a set of electron-transport carriers. Metabolomic data followed proteomics and showed the reduction of the ribulose-monophosphate (RuMP) pathway intermediates and the increase of the TCA cycle metabolites.Conclusion: Cells exposed to REEs display higher rates of growth but have lower carbon conversion efficiency compared to cells supplemented with Ca. The most plausible explanation for these physiological changes is an increased conversion of methanol into formate by XoxF-MeDH, which further stimulates methane oxidation but limits both the supply of reducing power and flux of formaldehyde into the RuMP pathway.

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Role of copper and iron in methane oxidation and bacterial biopolymer accumulation

Cited by 28 publications

References 121 publications

Effects of copper on expression of methane monooxygenases, trichloroethylene degradation, and community structure in methanotrophic consortia

Effects of copper on expression of methane monooxygenases, trichloroethylene degradation, and community structure in methanotrophic consortia

Simultaneous methane abatement and PHB production by Methylocystis hirsuta in a novel gas-recycling bubble column bioreactor

Rare Earth Elements Alter Redox Balance in Methylomicrobium alcaliphilum 20ZR

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