Model-based analysis of biocatalytic processes and performance of microbioreactors with integrated optical sensors.

Design and development of scale-down approaches, such as microbioreactor (µBR) technologies with integrated sensors, are an adequate solution for rapid, high-throughput and cost-effective screening of valuable reactions and/or production strains, with considerably reduced use of reagents and generation of waste. A significant challenge in the successful and widespread application of µBRs in biotechnology remains the lack of appropriate software and automated data interpretation of µBR experiments. Here, it is demonstrated how mathematical models can be usedas helpful tools, not only to exploit the capabilities of microfluidic platforms, but also to reveal the critical experimental conditions when monitoring cascade enzymatic reactions. A simplified mechanistic model was developed to describe the enzymatic reaction of glucose oxidase and glucose in the presence of catalase inside a commercial microfluidic platform with integrated oxygen sensor spots. The proposed model allowed an easy and rapid identification of the reaction mechanism, kinetics and limiting factors. The effect of fluid flow and enzyme adsorption inside the microfluidic chip on the optical sensor response and overall monitoring capabilities of the presented platform was evaluated via computational fluid dynamics (CFD) simulations. Remarkably, the model predictions were independently confirmed for µL- and mL- scale experiments. It is expected that the mechanistic models will significantly contribute to the further promotion of µBRs in biocatalysis research and that the overall study will create a framework for screening and evaluation of critical system parameters, including sensor response, operating conditions, experimental and microbioreactor designs.

Screening of organic solvents for bioprocesses using aqueous-organic two-phase systems.

The application of conventional organic solvents has been essential in several steps of bioprocesses in order to achieve sufficient economic efficiency. The use of organic solvents is frequently used either to partly or fully replace water in the reaction medium or as a process aid for downstream separation. Nowadays, manufacturers are increasingly requested to avoid and substitute solvents with hazardous potential. Therefore, the solvent selection must account for potential environmental hazards, health and safety problems, in addition to fulfilling the ideal characteristics for application in a process. For the first time, criteria including Environment, Health and Safety (EHS), as well as the technical requirements for reaction and separation have been reviewed, collected and integrated in a single organic solvent screening strategy to be used as a guideline for narrowing down the list of solvents to test experimentally. Additionally, we have also included a solvent selection guide based on the methodology developed in the Innovative Medicines Initiative CHEM21 (IMI CHEM21) project and applied specifically to water-immiscible solvents commonly used in bioprocesses.