Caught in-between: System for in-flow inactivation of enzymes as an intermediary step in “plug-and-play” microfluidic platforms

Abstract

The need for fast and comprehensive characterization of biocatalysts has pushed the development of new screening platforms based on microfluidics, capable of monitoring several parameters simultaneously, with new configurations of liquid handling, sample treatment and sensing. Modular microfluidics allows the integration of these newly developed approaches in a more flexible way towards increasing applicability of the microfluidic chips to different types of biocatalysts and reactions. A highly relevant operation in such a system is biocatalyst inactivation, which can enable the precise control of reaction time by avoiding the continuation of the reaction in another module or connecting tubes. Such control is important when different modules of reactors and/or sensing units are used and changed frequently. Here we describe the development, characterization and application of a module for rapid enzyme inactivation. The thermal inactivation platform developed is compared with a standard benchtop ThermoMixer in terms of inactivation efficiency for glucose oxidase and catalase. A higher activity loss was observed for enzyme inactivation under flow conditions (inactivation achieved at 120 s residence time at 338 K and 20 s residence time at 353 K) which indicated a high heat transfer to the fluid under dynamic conditions. Moreover, partial deactivation of the enzymes was observed for the continuous thermal inactivation module, when activity measurements were performed after 1 and 2 days following inactivation. The thermal inactivation unit presented can be easily integrated into modular microfluidic platforms and can be a useful addition for enzyme characterization and screening.

The rise of continuous flow biocatalysis – fundamentals, very recent developments and future perspectives

“…36 Worth to mention is also the recently published special issues devoted to microreactors in biotechnology. [37][38][39][40][41][42] Additionally, a very recent review article was published by Hughes dealing with applications of flow chemistry in the pharmaceutical industry focusing in the patent literature, 43 whereas Lee et al emphasized on the translation of the pharmaceutical manufacturing from batch to flow, 44 and Baumann et al concentrate on the perspectives of continuous flow chemistry in the pharmaceutical industry. 45 Monbaliu and co-workers summarize the impact of continuous flow on platform-chemicals derived from biomass.…”

The Promises and the Challenges of Biotransformations in Microflow

“…As summarized in Table , a variety of reactions were already optimized using microflow devices. Dissolved enzymes in microchannels could be used for e.g., fast biocatalyst screening and optimization of substrate–enzyme ratios at a variety of process conditions, as recently applied in hydrolysis of delignified wheat straw, or in the study of enzyme thermal inactivation . On the other hand, stainless steel or glass tubes of a few mm diameter packed with immobilized enzymes or cells are frequently applied.…”