Characterization of an enzymatic packed-bed microreactor: Experiments and modeling

Abstract

A micro packed-bed reactor (µPBR) based on two-parallel-plates configuration with immobilized Candida antarctica lipase B in the form of porous particles (Novozym ® 435) was theoretically and experimentally characterized. A residence time distribution (RTD) within µPBRs comprising various random distributions of particles placed in one layer was computationally predicted by a mesoscopic lattice Boltzmann (LB) method. Numerical simulations were compared with measurements of RTD, obtained by stimulus-response experiment with a pulse input using glucose as a tracer, monitored by an electrochemical glucose oxidase microbiosensor integrated with the reactor. The model was validated by a good agreement between the experimental data and predictions of LB model at different conditions.

Novozym 435: the “perfect” lipase immobilized biocatalyst?

“…In another research effort, N435 was also employed to analyze the advantages of a micro packed-bed reactor based on a two-parallelplate configuration to produce biodiesel. 458 In another investigation, Eruca sativa oil was used as a substrate in a comparison between N435 and Aspergillus niger lipase, obtaining a much higher yield using N435 (98.3% versus 56.4%). 459 N435 was also used to produce biodiesel from degummed crude palm oil and optimized by the response surface methodology.…”

The Promises and the Challenges of Biotransformations in Microflow

“…Microflow format was found beneficial also for packed‐bed reactors (Figures f and e) with biocatalysts immobilized in porous beads, on streptavidin‐coated superparamagnetic microbeads, in electrospun nanomats, or in various hydrogels, recently also prepared as alginate‐silica hybrids, which have the advantages of homogenous structure, better stability, and nontoxicity, and are injectable . Miniaturized packed‐bed reactors enabled not only very high enzyme loads, but also very good accessibility and operational stability of biocatalysts due to diminished fluid flow anomalies such as back mixing and dead zones, and very low‐pressure drop …”

“…Apart from frequently used fluorescence microscopy, thermal lens microscopy allows for ultra precise detection of single molecules in liquids based on optical absorption measurements, also enabling on‐line model validation of molecular transport in a liquid–liquid microflow . Furthermore, mesoscopic model verification and characterization of a packed‐bed reactor with immobilized Candida antarctica lipase B (CaLB) based on residence‐time distribution analysis were performed using integrated miniaturized glucose oxidase biosensor . The same biosensor was further integrated in a multifunctional microfluidic platform comprising a two‐sensor system interspersed with a mixing channel that enables inline continuous monitoring of glucose of various concentration ranges.…”

“…Process capacity enhancement using microflow systems typically encompasses scale‐up towards mesoscale reactors of a few milliliter volumes and further parallelization or internal numbering‐up . Two‐plate or lamina reactor systems present a very efficient tool for designing large scale production facilities comprising immobilized biocatalysts . Moreover, the first report on biotransformation performed in a two‐liquid phase system using a commercially available modular advanced flow reactor of a milliliter volume range revealed the highest reported productivity for the studied reaction .…”

“…This may not always be adapted to describe transport processes and chemical interactions that occur at the microscale. The molecular description should, therefore, be considered for understanding and predicting reaction‐diffusion dynamics in microreactors, posing the quest for the development of novel tools enabling multiscale modeling …”