Whole cell immobilization and catalysis in a Centrifugal Partition Chromatograph

Abstract

Biphasic reaction systems using enzymes as catalysts were recently operated in Centrifugal Partition Chromatography (CPC) devices. Since complex biotransformations involving co-factors are commonly operated using whole cell catalysts, this study deals with the implementation of these reaction systems in a CPC device. Therefore, cells from Saccharomyces cerevisiae in a biphasic system consisting of an aqueous phase (100mM phosphate buffer, pH=7.0) including the co-substrate glucose and heptane as organic phase were used to reduce two β-ketoesters of different polarity. It was found that biocompatibility and extractability in this process have opposed effects and need to be compromised. The cells were immobilized for 5h using the CPC reactor and the substrate was reduced steadily. The mechanism of immobilization was evaluated visually and traced back to the centrifugal forces as well as the inability of the cells to overcome the liquid–liquid interface.All in all, the CPC reactor for whole cells has conceptual advantages like easy continuous operation, stable catalyst immobilization without the use of a solid phase and in situ product removal, which may open possibilities for the small scale synthesis of fine chemicals using whole cells.