Heterogeneous Catalysts on the Move: Flow Chemistry with Fluid Immobilised (Bio)Catalysts

As both, continuous synthesis and (bio-)catalysis gained increasing interest in research as well as for industrial applications, ways for merging these fields enables novel opportunities for modern sustainable process development. In this contribution, an alternative approach for the application of immobilized enzymes in continuous flow processes is presented utilizing heterogeneous biocatalysts as a mobile phase. Based on superabsorber-entrapped enzymes and whole cells as a fluid heterogeneous phase, a segmented hydrogel/organic solvent system was developed. Its applicability was investigated with two entirely different model reaction systems, namely the alcohol dehydrogenase (ADH)-catalysed reduction of acetophenone, and the aldoxime dehydratase (Oxd)-catalysed dehydration of octanal oxime. In particular for solvent labile catalytic systems, this approach offers an alternative for the application of immobilized biocatalysts in a continuously running process beyond the classic packed bed and wall coated reactors.