Oscillations of pH in the urea–urease system in a membrane reactor

Abstract

Herein, we present direct experimental evidence of pH oscillatory dynamics in the urea–urease enzymatic reaction conducted in a continuous reactor–membrane–reservoir system. Our results are consistent with earlier model predictions requiring differential transport of H⁺ and substrate. We report oscillations with periods in hundreds of seconds and the amplitude of ∼0.1 pH units.