ISSN:
1572-9729
Schlagwort(e):
Methylosinus trichosporium
;
methanotroph
;
trichloroethene
;
methane monooxygenase
;
maximization of enzyme activity
;
groundwater
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
,
Energietechnik
,
Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
Notizen:
Abstract Soluble methane monooxygenase (sMMO) maximization studies were carried out as part of a larger effort directed towards the development and optimization of an aqueous phase, multistage, membrane bioreactor system for treatment of polluted groundwater. A modified version of the naphthalene oxidation assay was utilized to determine the effects of methane:oxygen ratio, nutrient supply, and supplementary carbon sources on maximizing and maintaining sMMO activity inMethylosinus trichosporium OB3b.Methylosinus trichosporium OB3b attained peak sMMO activity (275–300 nmol of naphthol formed h−1 mg of protein−1 at 25°C) in early stationary growth phase when grown in nitrate mineral salts (NMS) medium. With the onset of methane limitation however, sMMO activity rapidly declined. It was possible to define a simplified nitrate mineral salts (NMS) medium, containing nitrate, phosphate and a source of iron and magnesium, which allowed reasonably high growth rates (μmax 0.08 h−1) and growth yields (0.4–0.5 g cells/g CH4) and near maximal activities of sMMO. In long term batch culture incubations sMMO activity reached a stable plateau at approximately 45–50% of the initial peak level and this was maintained over several weeks. The addition of d-biotin, pyridoxine, and vitamin B12 (cyanocobalamin) increased the activity level of sMMO in actively growing methanotrophs by 25–75%. The addition of these growth factors to the simplified NMS medium was found to increase the plateau sMMO level in long term batch cultures up to 70% of the original peak activity.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00695208
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