Characterization of Two New Facultative Methanotrophs

The distribution of methane and methane-oxidizing bacteria in the water column of Lake Washington was determined monthly for 1 year. The methane profiles were relatively constant, with little stratification and low concentrations (0.05 to 0.5 ,uM). The number of methane-oxidizing bacteria detected by a filter-plating method was routinely <1/ml throughout the water column, and no incorporation or oxidation of methane was detected by radioisotopic labeling, even after methane was added. However, samples taken from the sediment-water interface contained as much as 3 ,uM methane and 50 CFU of methane-oxidizing bacteria per ml and showed significant rates of methane oxidation and incorporation. To define the region of maximum activity more precisely, vertical profiles of the sediment were examined. The concentration of methane increased with depth to a maximum of 150 to 325 p.M at 2.5 cm, and significant rates of methane oxidation were found within the top 2.5 cm. The apparent Kms for methane and oxygen were determined for samples from the top 1.0 cm of the sediment and found to be ca. 10 and 20 pM, respectively. Projected values for methane oxidation rates suggested that maximum methane oxidation occurred in the top 0.5 cm of the sediment.

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“…Electron microscopy. Thin sections of samples from enrichment cultures were prepared as described previously (10).…”

Section: Methodsmentioning

confidence: 99%

Seasonal Study of Methane Oxidation in Lake Washington

Lidstrom

Somers

1984

Appl Environ Microbiol

128

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“…Before the above study it was thought that methane oxidation may have been a plasmidborne trait [39][40][41][42]; however, with the findings of Lidstrom and colleagues [38,43] and the recent cloning of soluble methane monooxygenase genes (see Section 4), it is now generally thought that the essential function of methane oxidation is not plasmid-encoded.…”

Section: Plasmids In Methanotrophsmentioning

confidence: 99%

Genetics and molecular biology of methanotrophs

Murrell¹

1992

FEMS Microbiology Letters

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Over the last 20 years or so, the obligate methane‐oxidizing bacteria (methanotrophs) have attracted considerable interest. As they grow on a relatively cheap and abundant carbon source, they appeared ideal organisms for the production of bulk chemicals, single‐cell protein and for use in biotransformations. More recently their cooxidation properties have been investigated for bioremediation, including the removal of chlorinated compounds such as trichloroethylene from polluted groundwaters. These studies have resulted in a great deal of information on the physiology and biochemistry of methanotrophs but sadly the molecular biology and genetic studies of these organisms have lagged behind. This has been in part due to the obligate nature of the methanotrophs and the refractory nature of such organisms to conventional genetic analysis. However, the more recent availability of broad‐host range plasmids coupled with improvements in molecular biology methods have allowed the development of molecular genetic techniques for methanotrophs. The purpose of this review is to summarize what is known about the genetics and molecular biology of methanotrophs and how this information can be used to complement previous and current biochemical studies on the unique property of these bacteria, i.e. the ability to oxidize methane to methanol. Recent developments in molecular ecology techniques that may be applied to these apparently ubiquitous organism are also considered.

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“…They are clearly not necessary for growth on methanol, since facultative methylo- trophs are devoid of them. It has therefore been assumed that the membranes are associated specifically with the initial metabolism of methane, and this contention would appear to be supported by the fact that facultative methanotrophs only contain such membranes when grown on methane (94,123,195).…”

Section: Morphology and Physiologymentioning

confidence: 99%

Methane-oxidizing microorganisms.

Higgins¹,

Best²,

Hammond³

et al. 1981

Microbiological Reviews

139

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Fine structure of type I methane-utilizing bacteria .559 Fine structure of type II methane-utilizing bacteria .559 Effect of growth conditions on intracytoplasmic membranes .560 Phospholipid and fatty acid compositions of methanotrophs560 Exospore and cyst formation by methanotrophs .562 Ultrastructure of methane-utilizing yeasts .563 CARBON METABOLISM .563 The Serine Pathway .563 The Ribulose Monophosphate (Quayle) Cycle and Other Aspects of Carbon Assimilation by Type I Methanotrophs .567 The Dissimilatory Ribulose Monophosphate Pathway .570

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Characterization of Two New Facultative Methanotrophs

Cited by 38 publications

References 25 publications

Seasonal Study of Methane Oxidation in Lake Washington

Seasonal Study of Methane Oxidation in Lake Washington

Genetics and molecular biology of methanotrophs

Methane-oxidizing microorganisms.

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