Suspended Catharanthus roses cells form spherical clumps approximately 1.5 mm in diameter. Oxygen uptake is measured using the apparatus of Figure 9.13. Medium is recirculated with a superficial liquid velocity of 0.83 cm s1. At a bulk concentration of 8 mg l1, oxygen is consumed at a rate of 0.28 mg g1 (wet weight cells) h1. Assume that density and viscosity of the medium are similar to water, the specific gravity of wet cells is 1, and oxygen uptake is zero order. The effective diffusivity of oxygen in the clumps is 9 106 cm2 s1, or half that in the medium.\ (a) Does external mass transfer affect the oxygen uptake rate? (b) To what extent does internal mass transfer affect oxygen uptake?\ (c) Roughly, what would you expect the profile of oxygen concentration to be within the aggragates?