ISSN:
0006-3592
Keywords:
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
When a steady-state oxygen concentration is measured with a membrane-covered probe in an open system, the oxygen consumption in the unstirred layer gives rise to an error of measurement whose seriousness depends on the kinetics of the oxygen-consuming process. First-order oxygen consumption in the sample causes a proportional reduction in the signal so that the calibration in curve remains linear. A zeroth-order process causes the calibration curve to be offset from the origin, but it remains linear. Oxygen consumption according to the Michaelis-Menten equation causes the calibration curve to become nonlinear with the maximum deviation at the lower end of the scale. The error determines a lower limit for usefulness of membrane-covered probes. Steady-state kinetics at oxygen concentrations in the order of KM cannot be determined with a membrane-covered probe for enzyes with KM for oxygen lower than 0.01μM. In a dense culture of respiring microorganisms, no oxygen will reach the probe when the bulk concentration of oxygen is in the order of KM.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bit.260200604
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