Survey of measurement techniques for gas-liquid mass transfer coefficient in bioreactors

In many fermentation processes, oxygen transfer is the rate limiting step. Correct measurement and subsequent estimation of the volumetric mass transfer coefficient is a crucial step in the design procedure of bioreactors. This article discusses some of the methods that are commonly used for the measurement of the mass transfer coefficient and their applicability for measurement in large scale bioreactors. It has been found that among the methods discussed here, the dynamic pressure method appears most useful for industrial scale bioreactors, with a small degree of approximations for gas-liquid mixing in the reactor and is suitable for large scale bioreactors with errors less than 10%, over the entire range of the operating conditions encountered in the fermenter operation. (C) 1999 Elsevier Science S.A. All rights reserved.