Designing an enzymatic oscillator: Bistability and feedback controlled oscillations with glucose oxidase in a continuous flow stirred tank reactor

摘要

The reaction of glucose with ferricyanide catalyzed by glucose oxidase from Aspergillus niger gives rise to a wide range of bistability as the flow rate is varied in a continuous flow stirred tank reactor.Oscillations in pH can be obtained by introducing a negative feedback on the autocatalytic production of H~+ that drives the bistability.In our experiments,this feedback consists of an inflow of hydroxide ion at a rate that depends on [H~+] in the reactor as k_0[OH~-]_0[H~+]/(K+[H~+]).pH oscillations are found over a broad range of enzyme and ferricyanide concentrations,residence times (k_0~(-1)),and feedback parameters.A simple mathematical model/quantitatively accounts for the experimentally found oscillations.