(355s) Planar Micro-Contactors for Electric-Field-Enhanced Separation of Valuable Chemicals from Complex Reaction Mixtures

Many valuable chemicals and pharmaceuticals are produced in grams rather than tonnes. Pharmaceutical companies became invest their funds to the development of versatile micro- or mini-plants.

We realized that many pharma-products are synthetized in ionic form. Their separation in extractors or membrane modules can be enhanced by an external electric field. Microfluidic systems represents an ideal platform for the application of electric field due to the possibilities to intensively remove of the generated Joule heat.

We fabricated planar membrane microseparators characterized by a high surface to volume ratio. A thin dialysis membrane separating the feed and extract streams allowed to arrange both co-current and counter-current regimes in the micro-contactor. Electric field imposed perpendicularly to the membrane significantly intensified interfacial transport of charged products. Ion-exchange membranes provided conductive connections among electrode reservoirs and feed/extract streams.

The micro-contactor was tested for the continuous separation of 6-aminopenicillanic acid synthetized in a preceding step by a free penicillin acylase and mandelic acid synthetized by an immobilized lipase. In both cases, the product separation was significantly accelerated and almost 100% separation efficiency was achieved. When mandelic acid was separated from the other components of the feed stream, we were able to obtain different enantiomeric ratios of the L- and D- forms. The effects of the applied voltage and residence time on the separation efficiency and productivity were studied in extensive parametrical studies.

The properties of the electric-field-driven micro-contactor was also investigated theoretically. Several mathematical models were derived and numerically analyzed. We identified regions in a parameter space characterized by a high yield and separation efficiency. Correlations for the estimation of boundaries of these regions were suggested.

Our findings can contribute to the process intensification in modern mini-plants and reveal the capabilities of electric-filed-driven operations in pharma industry.

Romanov et.al, Biotechnology and Bioengineering 118, 715-724, 2021.