MEMBRANE BIOREACTORS.

Abstract

A discussion is presented of bioreactors from the viewpoint of improved performance over other types of reactors. These reactors are inherently more efficient because they run continuously. High cell densities can be obtained, exceeding 100 g/L of dry weight of cells, if necessary. This usually implies cell concentrations of 10**1**1-10**1**2 per mL, close to theoretical cell loadings. High dilution rates can be used, as a direct result of the high cell concentrations. Control of the environment is easy with the membrane recycle fermentor. If the membrane module is properly designed, the bulk of the fermentation or reaction should occur in the reaction vessel. Thus control of temperature, pH, and dissolved oxygen can be done with current methods. Membrane recycle bioreactors can process both soluble and insoluble substrates, unlike the hollow fiber and most immobilized whole-cell bioreactors. This concept is probably the easiest to incorporate into an existing plant.