Dynamic measurement of the volumetric oxygen transfer coefficient in fermentation systems.

Introduction Much has been written and said about the scale-up of fermentation systemsS). In general, it has been agreed that the best scale・,-up method is to maintain a constant voiumetric oxygen mass transfer coeMcient. The problem with this procedure has been the differing methods by which the transfer coeMelent has been obtained. Various investigators have used the su}fite oxidation2), polarographicS'iO), chemical gassing-outS), 02 up-take rate by growing Aerobacter aero.ffenesS), and other methodsE'S). Agreement is often lacking among the different methods. Further some do not give internally consistent results when utilized on large scale fermentation systems. The method proposed in this paper has been found ro be rapid and consistent. Further, it is a direct method, i. e. it is based un utilizing the fermenting system itself, The dynamic method is based on following the dissolved 02 concentration during a brief interruption of the aeration of the fermenting system. Only a fast response, sterilizable, dissolved oxygen probe is required to obtain the necessary data. Given a typicai aerated ferrnentation system for which the following symbols apply,