Following the material characterisation in Part A, Part B evaluates stimuli-responsive hydrogels in a plug-flow reactor under changing temperature (25-40 °C) and pH (8-4) conditions, using formate dehydrogenase for NADH regeneration. Temperature changes caused transient increases in activity, followed by partial or pronounced loss after returning to mild conditions. Under pH changes, activity decreased under acidic conditions but recovered fully for the responsive hydrogels, which maintained residual activity of 93.3 ± 26.3 % for the pH-responsive and 91.0 ± 9.8 % for the dual-responsive carriers, whereas non-responsive silica carriers retained only 27.6 ± 10.2 %. This behaviour is attributed to gel shrinkage, which restricts mass transport and reduces enzyme exposure to the surrounding environment, demonstrating the potential of responsive hydrogels as adaptive enzyme carriers for biocatalysis.
The study is a collaboration between the Institute for Thermal Separation Processes and the Institute of Technical Biocatalysis, connected through the CRC 1615 SMART Reactors, in association with the United Nations University Hub on Engineering to Face Climate Change at Hamburg University of Technology and the United Nations University Institute for Water, Environment and Health (UNU-INWEH).
Kathrin Marina Eckert, Kayla Reata Dittmer, Sherliana Setiawan, Daniel Ohde, Andreas Liese, Irina Smirnova (2026). Enzyme Immobilization on Stimuli-Responsive Hydrogels - Part B. Impact of Carrier Responsiveness on Reactor Performance. Ind. Eng. Chem. Res. 65 (26).
