Oxygen transfer in membrane-ceramic composite materials for immobilized-cell monolithic reactors

A novel bioreactor concept is described for facilitated gas-liquid mass transfer, specifically oxygen supply, at low shear rates and low power input. The cross flow monolithic reactor is a single piece of ceramic consisting of continuous flow passages manifolded in a cross flow arrangement. Liquid medium circulates through the passages in one direction and gas circulates through the passages in an orthogonal direction; thus, the two streams are contacted across a large area of a porous ceramic, gas permeable membrane composite.A test cell was designed and used to measure the rate of oxygen transfer across such a composite. High oxygen transfer rates (6.62g O(2) x l(-1) x hr(-1)), with minimal power requirements (estimated below 5 x 10(-3) watts/l reactor volume), were found. This corresponds to a transfer efficiency of greater than 1000 kg O(2)/kW . hr, orders of magnitude greater than the values reported by Serieys, et al.(14) due to the low flow rates and low pressure drops required in a cross flow monolith. This contacting configuration could be employed with highly aerobic, immobilized-cell fermentations to enhance oxygen transfer rates with a parallel decrease of process power requirements.