Applications of a colorimetric plate assay for soluble methane monooxygenase activity

Graham, David W.; Korich, D. G.; LeBlanc, R P; Sinclair, Nicholas; Arnold, Robert G.

doi:10.1128/aem.58.7.2231-2236.1992

Cited by 100 publications

(42 citation statements)

References 17 publications

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“…The routine qualitative detection of sMMO activity was performed using the naphthalene oxidation assay (Brusseau et al, 1990;Graham et al, 1992) on whole cells in liquid and plate cultures.…”

Section: Sds-pagementioning

confidence: 99%

Regulation of methane oxidation in the facultative methanotroph Methylocella silvestris BL2

Theisen

Ali

Radajewski

et al. 2005

Molecular Microbiology

136

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SummaryThe molecular regulation of methane oxidation in the first fully authenticated facultative methanotroph Methylocella silvestris BL2 was assessed during growth on methane and acetate. Problems of poor growth of Methylocella spp. in small-scale batch culture were overcome by growth in fermentor culture. The genes encoding soluble methane monooxygenase were cloned and sequenced, which revealed that the structural genes for soluble methane monooxygenase, mmoXYBZDC , were adjacent to two genes, mmoR and mmoG , encoding a σ σ σ σ 54 transcriptional activator and a putative GroEL-like chaperone, located downstream (3 ′ ′ ′ ′ ) of mmoC . Transcriptional analysis revealed that the genes were all cotranscribed from a σ σ σ σ 54 -dependent promoter located upstream (5 ′ ′ ′ ′ ) of mmoX . The transcriptional start site was mapped. Transcriptional analysis of soluble methane monooxygenase genes and expression studies on fermentor grown cultures showed that acetate repressed transcription of sMMO in M. silvestris BL2. The possibility of the presence of a particulate, membrane-bound methane monooxygenase enzyme in M. silvestris BL2 and the copper-mediated regulation of soluble methane monooxygenase was investigated. Both were shown to be absent. A promoter probe vector was constructed and used to assay transcription of the promoter of the soluble methane monoxygenase genes of M. silvestris BL2 grown under various conditions and with different substrates. These data represent the first insights into the molecular physiology of a facultative methanotroph.

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Section: Sds-pagementioning

confidence: 99%

Regulation of methane oxidation in the facultative methanotroph Methylocella silvestris BL2

Theisen

Ali

Radajewski

et al. 2005

Molecular Microbiology

136

View full text Add to dashboard Cite

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“…If so, the pMMO may have been partly responsible for TCE degradation and methane consumption during reactor operation. Although there have been no reports of methanotrophic cultures capable of expressing pMMO in a low copper environment, methanotrophs have been grown in a low copper environment without expression of sMMO (Graham et al, 1992). Further research is needed to determine if sMMO expression is limited in enrichments with continuous TCE exposure.…”

Section: Discussionmentioning

confidence: 99%

Trichloroethylene and methane feeding strategies to sustain degradation by methanotrophic enrichments

Walter¹,

Strand²,

Herwig³

et al. 1997

Water Environment Research

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Metabolite toxicity production during trichloroethylene (TCE) degradation by methanotrophic bacteria can lead to partial or complete inactivation of the TCE‐degrading enrichment. The general objectives of this research were to determine if TCE and methane feeding strategies could be selected that would reduce metabolite toxicity effects and determine operating conditions that would sustain TCE‐degrading methanotrophic enrichments. In batch treatment of TCE with and without methane, the presence of methane doubled the amount of TCE degraded per unit biomass (0.051 mg TCE/mg biomass). In a closed complete‐mix methanotrophic enrichment reactor continuously fed TCE and methane, reactor failure occurred at a loading of only 0.005 mg TCE/mg volatile suspended solids (VSS) · d. In the same type of reactor operation with intermittent TCE feeding and continuous methane feeding, TCE degradation was sustained at daily loadings of 0.03 mg TCE/mg VSS · d. The intermittent TCE‐fed reactor could produce an effluent TCE concentration below the drinking water standard (0.005 mg/L) at a higher TCE loading than the continuous‐fed system (0.03 versus 0.0025 mg TCE/mg VSS · d). The system with intermittent TCE feeding provided more efficient use of methane relative to TCE degradation. The amount of methane consumed per unit of TCE degraded was 33 and 167 mg methane/mg TCE for the intermittent and continuous TCE‐fed operations, respectively. With continuous TCE exposure, the methanotrophic population in the continuous TCE‐fed reactor changed to a type that is characterized by having less soluble TCE‐oxidizing enzymes and slower TCE oxidation rates.

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“…The population of total aerobic bacteria in the soil samples was estimated by the standard dilution plate technique using tryptone yeast extract medium (Rand et al, 1976) and expressed as colony forming units (CFU)/g dry soil. Methane oxidizers with soluble methane mono-oxygenase (sMMO) activity from soils were enumerated following an enrichment protocol (Graham et al, 1992). Triplicate plates for each dilution were incubated in vacuum desiccators under an atmosphere of 5% CH 4 in air maintained by replenishing the headspace atmosphere with CH 4 on every 4 days, for total 30 days in an incubator.…”

Section: Microbiological Analysesmentioning

confidence: 99%

Interactive effect of biochar size and organic amendments on methane consumption in a tropical vertisol

Kollah

Dubey

Parasai

et al. 2015

Soil Use and Management

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Biochar (BC) application to agricultural soil has been proposed as an effective countermeasure to mitigate climate change. A laboratory incubation experiment was carried out to gain insight into the effectiveness of BC on methane (CH4) consumption in a tropical clayey vertisol. Except for the control treatment, BC of two different sizes (<0.25 or 0.25–2.00 mm) was mixed with vermicompost (VC), poultry manure (PM) or farmyard manure (FYM). BC and organic amendment were added to soil at 10% w/w and 80 kg N/ha, respectively. BC increased CH4 consumption rate, k, in soil, irrespective of organic amendment type. The CH4 consumption potential of soil was greater with the smaller size BC (<0.25 mm). Of the three organic amendments, VC exhibited the highest k (0.105) followed by FYM (0.093) and PM (0.072). BC (<0.25 mm) + PM was the most effective of the organic amendments in enhancing CH4 consumption (k = 0.242). The lag phase varied between 7.3 day (control) and 1.0 day (soil + VC). Results revealed that there was a significant (P < 0.0001) effect of organic amendment and BC on CH4 consumption, CO2 production and microbial abundance. Cumulative CO2 production (mg/g soil) varied between 2.15 (control) and 8.77 (soil + PM + BC < 0.25 mm). Pearson's correlation analysis showed significant correlation between CH4 consumption and methanotrophs abundance (P < 0.001). The study shows that BC enhanced CH4 consumption potential in agricultural land on a tropical vertisol, particularly using the smaller size (<0.25 mm), and could be an effective strategy to mitigate atmospheric CH4.

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Applications of a colorimetric plate assay for soluble methane monooxygenase activity

Cited by 100 publications

References 17 publications

Regulation of methane oxidation in the facultative methanotroph Methylocella silvestris BL2

Regulation of methane oxidation in the facultative methanotroph Methylocella silvestris BL2

Trichloroethylene and methane feeding strategies to sustain degradation by methanotrophic enrichments

Interactive effect of biochar size and organic amendments on methane consumption in a tropical vertisol

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