Front Cover: Microfluidic-Assisted Evolution of a Robust NAD+-Dependent Enzyme with Improved Isobutanol Tolerance at Elevated Temperatures (ChemSusChem 20/2025)

The Front Cover shows a microfluidic chip that was used in an enzyme engineering approach utilizing microdroplet-based UHTS to optimize an aldehyde dehydrogenase towards higher temperature stability and solvent tolerance. The optimized enzyme was then applied as part of a multi-enzyme cascade as indicated by the circle of enzyme structures above the chip. The ultimate goal is a continuous process for the conversion of glucose into isobutanol in a two-phase system using these enzymes and based on the formation of an isobutanol phase at sufficiently high concentration and with continuous removal of the organic phase, as shown by the reactor in the background. More information can be found in the Research Article by V. Sieber and co-workers (DOI: 10.1002/cssc.202501120).