The measurement of effective substrate diffusities within whole cell suspensions using a diffusion‐limited hollow fibre reactor

Abstract

AbstractAn immobilised whole cell membrane reactor system is described which permits estimation of effective substrate diffusivities within whole cell suspensions. The reactor unit uses a membrane to separate the cell slurry from the nutrient solution (e.g. an artificial kidney hollow fibre dialyser). Whole cells are pumped into the shell side of the unit and clamped off. Substrate solution makes one pass through the dialyser tube side at a flow rate such that its conversion over the complete reactor does not exceed 10%. Under such conditions the reactor operates differentially; previously published mathematical expressions being used in evaluating the effective substrate diffusivity, once η (the effectiveness factor) is determined. The value of η can be estimated readily from the true reaction rate (in the absence of diffusional limitations) and the experimentally observed reaction rate. A hypothetical example is presented. The advantages and disadvantages of the method are discussed.