Linked Life Data

10753443

Source:http://linkedlifedata.com/resource/pubmed/id/10753443

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2000-8-2
pubmed:abstractText
A metabolic model describing growth of Methylosinus trichosporium OB3b and cometabolic contaminant conversion is used to optimize trichloroethene (TCE) conversion in a bioreactor system. Different process configurations are compared: a growing culture and a nongrowing culture to which TCE is added at both constant and pulsed levels. The growth part of the model, presented in the preceding article, gives a detailed description of the NADH regeneration required for continued TCE conversion. It is based on the metabolic pathways, includes Michaelis-Menten type enzyme kinetics, and uses NADH as an integrating and controlling factor. Here the model is extended to include TCE transformation, incorporating the kinetics of contaminant conversion, the related NADH consumption, toxic effects, and competitive inhibition between TCE and methane. The model realistically describes the experimentally observed negative effects of the TCE conversion products, both on soluble methane monooxygenase through the explicit incorporation of the activity of this enzyme and on cell viability through the distinction between dividing and nondividing cells. In growth-based systems, the toxicity of the TCE conversion products causes rapid cell death, which leads to wash-out of suspended cultures at low TCE loads (below microM inlet concentrations). Enzyme activity, which is less sensitive, is hardly affected by the toxicity of the TCE conversion products and ensures high conversions (>95%) up to the point of wash-out. Pulsed addition of TCE (0.014-0.048 mM) leads to a complete loss of viability. However, the remaining enzyme activity can still almost completely convert the subsequently added large TCE pulses (0.33-0.64 mM). This emphasizes the inefficient use of enzyme activity in growth-based systems. A comparison of growth-based and similar non-growth-based systems reveals that the highest TCE conversions per amount of cells grown can be obtained in the latter. Using small amounts of methane (negligible compared to the amount needed to grow the cells), NADH limitation in the second step of this two-step system can be eliminated. This results in complete utilization of enzyme activity and thus in a very effective treatment system.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
8756-7938
pubmed:author
pubmed:issnType
Print
pubmed:volume
16
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
189-98
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:articleTitle
NADH-Regulated metabolic model for growth of Methylosinus trichosporiumOB3b. Cometabolic degradation of trichloroethene and optimization of bioreactor system performance.
pubmed:affiliation
Chemical Engineering and Biochemistry Departments, University of Groningen, NL-9747 AG Groningen, The Netherlands.
pubmed:publicationType
Journal Article, Comparative Study