According to Ulf Hanefeld and Frank Hollmann of Delft University of Technology, being open to the unexpected is one of the most important qualities of a scientist. It was this attitude that led them to discover an enzymatic reaction that was previously thought impossible: transesterification in water.

Alcohol oxidases, which oxidise alcohol groups, are not usually associated with transesterification. So it came as quite a surprise when Delft professor Frank Hollmann observed ‘new’ peaks on a gas chromatography spectrum. ‘This happened during a collaboration with researchers from Guangzhou, with whom we wanted to expand the substrate scope of alcohol oxidases. The GC sample turned out to contain traces of esters, which you would never expect with alcohol oxidases.’

Professor Ulf Hanefeld, head of the same biocatalysis department as Hollmann, explains why this is so special: ‘Alcohol oxidases are redox enzymes, so the underlying mechanism works with electron transfer. The reaction we are now seeing, transesterification, works on a completely different principle. This is therefore a huge step forward. Mentally speaking, it’s almost impossible to comprehend.’