ISBN 9783843934688

978-3-8439-3468-8, Reihe Technische Chemie

Jonas Frederik Krause
Biocatalytic Conversions in a Centrifugal Partition Chromatograph

125 Seiten, Dissertation Technische Universität Dortmund (2017), Softcover, A5

Zusammenfassung / Abstract

A Centrifugal Partition Chromatograph (CPC) is a liquid-liquid chromatograph that is commonly used to separate mixtures. For this purpose, one liquid phase is immobilized in a cascade of chambers by a centrifugal field as stationary phase and another immiscible liquid phase is pumped through as mobile phase. Mixtures are then separated by the different partition of components in the biphasic system. In this multistage process of dispersion and coalescence a large interface to volume ratio is created and with it interfacial mass transport is enhanced. This two-phase handling may provide a way to realize an efficient substrate supply of low soluble substrates to immobilized biocatalysts within the stationary phase. In order to evaluate the applicability of this method and the individual behavior of different biocatalysts during CPC operation, a free enzyme, a crude cell lysate and a whole cell catalyst were used to convert substrates. It was shown that biphasic hydrolysis was realized successfully using a free lipase and comparable product formation rates to a stirred tank reactor were achieved. The optimal catalyst concentration for maximum product formation rates were shifted in CPC towards smaller concentrations. This behavior indicated, that the operating window in the CPC was also shifted, which was attributed to the different interface generation and interface residence times. Furthermore, it was possible to synthesize product by a crude lysate in CPC. However, during operation protein precipitation at the interface and activity losses were observed. Thus, it was found that the effectivity and usability of the biocatalyst in the CPC is determined by the hydrodynamics and catalyst properties. As a last catalyst, a whole cell was kept stationary in the CPC successfully and reactions were carried out continuously. In summary, the CPC offers a way to keep biocatalysts stationary without solid binding techniques and allows continuous operation with similar efficiencies as in stirred tank reactors. However, the individual properties of catalysts applied and the hydrodynamics in the CPC chambers have to be considered for an effective application.