Modularized Biocatalysis: Immobilization of Whole Cells for Preparative Applications in Microaqueous Organic Solvents

The use of whole-cell biocatalysts enables catalyst application in microaqueous reaction systems, in which the liquid phase consists of high substrate loadings in organic solvents, to enable access to high concentrations of easy-to-purify product. One current research focus is the modularization of single reaction steps to (i)enable flexible combinations into multi-step enzyme reactions, (ii)investigate ideal reaction conditions, and (iii)facilitate catalyst handling and recycling. Therefore, we published the easy-to-apply encapsulation of a lyophilized whole-cell catalyst in a polymeric membrane recently. These catalytic teabags were demonstrated to enable flexible catalyst combinations for multi-step reactions and excellent recyclability during repeated batch experiments. We now describe the applicability of these teabags on a larger scale by using the new SpinChem reactor and a classical stirred-tank reactor model. As an alternative, we investigate the described alginate entrapment approach and compare the results. The carboligation reaction towards (R)-benzoin, using lyophilized E.coli that enclose Pseudomonas fluorescens benzaldehyde lyase (EC 4.1.2.38), served as a model reaction. It was demonstrated that the catalytic teabags are scalable and perform equally on the investigatory 5mL scale and the preparative 140mL reactor scale. Tested in a more advanced application, the teabags were proven to be useful in a one-pot two-step reaction for the gram-scale production of 1-phenylpropane-1,2-diol by using the SpinChem reactor, which allowed to reach an industrially relevant product concentration (32.9gL(-1)) and space-time yield (8.2gL(-1)d(-1)).