Recent remarkable progress in understanding and engineering enzymes and whole cells as highly selective and environment-friendly catalysts enabling novel routes for the production of pharmaceuticals, fine and platform chemicals, and biofuels has spurred the quest for fast biocatalyst screening and development of efficient processes with long-term biocatalyst use. Besides this, current efforts towards more sustainable production systems and bio-based products have triggered an intense research on chemo-enzymatic cascades and establishment of continuous end-to-end processing. Microreaction technology, which has in the last two decades changed the paradigm in the laboratory and production scale organic synthesis, is recently gaining attention also in the field of applied biocatalysis. Based on the trends highlighted within this article, microfluidic systems linked with appropriate monitoring and feedback control can greatly contribute to successful implementation of biocatalysis in industrial production. Microflow-based droplets facilitate ultrahigh-throughput biocatalyst engineering, screening at various operational conditions, and very fast collection of data on reaction kinetics using minute amounts of time and reagents. Harnessing the benefits of microflow devices results in faster and cheaper selection of substrate(s) and media, and development of suitable immobilization methods for continuous biocatalyst use. Furthermore, the use of highly efficient reactor designs integrated with downstream processing enabling also faster and more reliable scale-up can bridge the gap between the academic research and industrial use of biocatalysts.
Authors:Uroš Novak, Daniela Lavric and Polona Žnidaršič-Plazl
The performance of the Corning AFR™ Low Flow (LF) fluidic module for Candida antarctica lipase B-catalyzed isoamyl acetate synthesis in an n-heptane–buffer two-liquid phase system was evaluated. Obtained flow regime of dispersed n-heptane droplets in a continuous buffer phase, which enables in situ extraction of the produced isoamyl acetate to the n-heptane phase, provides a very large interfacial area for the esterification catalyzed by an amphiphilic lipase B, which positions itself on the n-heptane–buffer interface. Productivities obtained were the highest reported so far for this reaction and indicate that Corning Advanced-Flow Reactor™ (AFR™) modules are also very efficient for carrying out biotransformations in two-phase systems. Additionally, for the separation of the n-heptane from the aqueous phase, a membrane separator consisting of a hydrophobic PTFE membrane was integrated, which enabled the reuse of biocatalyst in several consecutive biotransformations.