The short- and long-term effects of environmental conditions on anaerobic methane oxidation coupled to nitrite reduction

He, Zhao; Geng, Sha; Shen, Li‐dong; Lou, Liping; Zheng, Ping; Xu, Xinhua; Hu, Baolan

doi:10.1016/j.watres.2014.09.055

Cited by 102 publications

(37 citation statements)

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“…Moreover, salinity adaption (at 20 g NaCl liter Ϫ1 ) of denitrifying methanotrophs has been observed in a freshwater culture (24). These findings showed that AOM coupled to nitrite reduction may occur in marine systems and that NC10 bacteria may mediate this process, which indicated the potential importance of NC10 bacterium-driven methanotrophy in marine systems.…”

mentioning

confidence: 73%

“…5c, the denitrifying methanotrophic culture reached the maximum specific activity (1.56 Ϯ 0.17 mol CH 4 h Ϫ1 g Ϫ1 VSS) at 20.5‰ of salinity (i.e., the salinity of the enrichment media) and decreased at lower or higher salinities, which suggested that a halophilic denitrifying methanotrophic culture was obtained. Denitrifying methanotrophic activity was hardly observed at 1‰ (19.5‰ lower than the optimal salinity) of salinity (near the salinity of the freshwater medium), whereas a previous freshwater culture had the highest activity at this salinity (24). However, the culture was still active at a high salinity level of 40‰ (19.5‰ higher than the optimal salinity), and the denitrifying methanotrophic activity was 0.84 Ϯ 0.16 mol CH 4 h Ϫ1 g Ϫ1 VSS, approximately half of the maximum activity seen at 20.5‰ salinity.…”

Section: Figmentioning

confidence: 92%

“…Levels of nitrite, nitrate, and volatile suspended solids (VSS) were measured by standard methods (28), and methane was quantified by the use of an Agilent 6890 gas chromatograph (Agilent, USA) equipped with a flame ionization detector (FID) as previously described (24). The pH value was determined using a model FE20 pH meter (Mettler-Toledo, Shanghai, China).…”

Section: Methodsmentioning

confidence: 99%

“…Notably, the marine denitrifying methanotrophic culture became inactive at the salinity of freshwater medium (ϳ1‰), which suggested that these denitrifying methanotrophs in the marine culture had physiological properties distinct from those seen in freshwater cultures (24), although they showed striking resemblances in 16S rRNA and pmoA gene sequences ( Fig. 2 and 3).…”

Section: Figmentioning

confidence: 97%

“…On the basis of the existing molecular biological evidence, we can deduce that NC10 bacteria inhabit several marine systems, but we cannot guarantee that these NC10 bacteria perform the process of AOM coupled to nitrite reduction. Very recently, salinity adaption of freshwater denitrifying methanotrophs has been observed at a salinity stress level of 20 g NaCl liter Ϫ1 (24), which raised the possibility that the process of AOM coupled to nitrite reduction occurs in marine systems. However, the growth of denitrifying methanotrophs could not be observed in the process of salinity adaption (24); therefore, whether denitrifying methanotrophs are able to grow in saline water remains unknown.…”

Section: Figmentioning

confidence: 99%

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Anaerobic Oxidation of Methane Coupled to Nitrite Reduction by Halophilic Marine NC10 Bacteria

Geng

Cai

et al. 2015

Appl Environ Microbiol

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Anaerobic oxidation of methane (AOM) coupled to nitrite reduction is a novel AOM process that is mediated by denitrifying methanotrophs. To date, enrichments of these denitrifying methanotrophs have been confined to freshwater systems; however, the recent findings of 16S rRNA and pmoA gene sequences in marine sediments suggest a possible occurrence of AOM coupled to nitrite reduction in marine systems. In this research, a marine denitrifying methanotrophic culture was obtained after 20 months of enrichment. Activity testing and quantitative PCR (qPCR) analysis were then conducted and showed that the methane oxidation activity and the number of NC10 bacteria increased correlatively during the enrichment period. 16S rRNA gene sequencing indicated that only bacteria in group A of the NC10 phylum were enriched and responsible for the resulting methane oxidation activity, although a diverse community of NC10 bacteria was harbored in the inoculum. Fluorescence in situ hybridization showed that NC10 bacteria were dominant in the enrichment culture after 20 months. The effect of salinity on the marine denitrifying methanotrophic culture was investigated, and the apparent optimal salinity was 20.5‰, which suggested that halophilic bacterial AOM coupled to nitrite reduction was obtained. Moreover, the apparent substrate affinity coefficients of the halophilic denitrifying methanotrophs were determined to be 9.8 ؎ 2.2 M for methane and 8.7 ؎ 1.5 M for nitrite.A naerobic oxidation of methane (AOM) occurs extensively in natural ecosystems and is a crucial biological sink in the global methane cycle that maintains the balance of greenhouse gas content in the atmosphere (1). To date, five electron acceptors that support AOM, including AOM coupled to sulfate reduction (2), nitrite reduction (3), nitrate reduction (4), iron reduction (5), and manganese reduction (5), have been discovered in natural settings. Moreover, on the basis of bioenergetic calculations, researchers have speculated that several other types of AOM (e.g., AOM coupled to perchlorate reduction, arsenate reduction, and selenate reduction) may exist in nature (6); however, these possible types have not yet been confirmed. In particular, AOM coupled to nitrite reduction has been a predominant research focus in the past several years. AOM coupled to nitrite reduction was also called nitrite-dependent anaerobic methane oxidation (ndamo) in previous reports. It has been demonstrated that AOM coupled to nitrite reduction is mediated by the bacterium "Candidatus Methylomirabilis oxyfera" (denitrifying methanotroph) (7), which is affiliated with the candidate NC10 phylum (8). This candidate division (NC10 phylum) was first defined by classification of environmental sequences retrieved from aquatic microbial formations in flooded caves (9). To date, our knowledge regarding the NC10 phylum has stemmed largely from research into "Ca. Methylomirabilis oxyfera" and "Ca. Methylomirabilis oxyfera"-like bacteria. According to the phylogenetic affiliations of 16S rRNA gene sequ...

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confidence: 73%

Section: Figmentioning

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Section: Figmentioning

confidence: 97%

Section: Figmentioning

confidence: 99%

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Anaerobic Oxidation of Methane Coupled to Nitrite Reduction by Halophilic Marine NC10 Bacteria

Geng

Cai

et al. 2015

Appl Environ Microbiol

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Denitrification coupled with methane oxidation in a membrane bioreactor after methanogenic pre‐treatment of wastewater

Sánchez

Rodríguez-Hernández

Buntner

et al. 2016

J of Chemical Tech & Biotech

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BACKGROUND The presence of dissolved methane is an important environmental problem related to greenhouse gas emissions from wastewater treated in methanogenic bioreactors. Methane has a global warming potential of 28. For low‐strength wastewaters, such as sewage, dissolved methane could account for up to 50% of the total methane produced. Dissolved methane is easily desorbed from effluents when released into the environment or post‐treated in aerobic bioreactors. The use of dissolved methane as a carbon source for biological denitrification has been proposed as an alternative for reducing both greenhouse gas emissions and nitrogen concentrations in treated wastewater. RESULTS The effluent of a methanogenic reactor operating at ambient temperature was post‐treated in a two‐compartment biological membrane bioreactor (MBR). The first compartment consisted of an anoxic denitrification reactor in which dissolved methane was oxidized. The second compartment was an aerobic membrane filtration reactor. Up to 60% nitrogen removal and 95% methane consumption were observed. Batch experiments indicated the presence of microorganisms that were capable of denitrification using dissolved methane. CONCLUSIONS Denitrification using dissolved methane as a carbon source was feasible in an anoxic–aerobic MBR system. Denitrification resulted from a mixture of aerobic and anaerobic methane oxidizing bacteria, anammox and heterotrophic bacteria activity. © 2016 Society of Chemical Industry

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Enrichment and Isolation of Aerobic and Anaerobic Methanotrophs

2019

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The short- and long-term effects of environmental conditions on anaerobic methane oxidation coupled to nitrite reduction

Cited by 102 publications

References 28 publications

Anaerobic Oxidation of Methane Coupled to Nitrite Reduction by Halophilic Marine NC10 Bacteria

Anaerobic Oxidation of Methane Coupled to Nitrite Reduction by Halophilic Marine NC10 Bacteria

Denitrification coupled with methane oxidation in a membrane bioreactor after methanogenic pre‐treatment of wastewater

Enrichment and Isolation of Aerobic and Anaerobic Methanotrophs

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