Phenol and Trichloroethylene Degradation by 'Pseudomonas cepacia' G4: Kinetics and Interactions between Substrates

摘要

Intact cells of Pseudomonas cepacia strain G4 completely degraded trichloroethylene (TCE) following growth with phenol. Degradation kinetics were determined for both phenol, used to induce requisite enzymes, and TCE, the target substrate. At phenol concentrations above 50 microM, phenol degradation was inhibited, yielding an apparent K(sub i) of 0.45 mM as modeled by the Haldane expression. To eliminate experimental problems associated with TCE volatility and partitioning, a 'no-headspace' assay was developed allowing for direct and accurate determinations of aqueous TCE concentration. Using this assay procedure, apparent K(s) and V(max) values determined for TCE degradation by intact cells were 5.6 microM and 7.9 nmole/(min times mg protein) respectively. Following a transient lag period, P. cepacia G4 degraded TCE at concentrations of at least 300 microM TCE with no apparent retardation in rate.