Uwe T Bornscheuer1, Alex Toftgaard Nielsen2. 1. Institute of Biochemistry, Department of Biotechnology & Enzyme Catalysis, Greifswald University, 17487 Greifswald, Germany. Electronic address: uwe.bornscheuer@uni-greifswald.de. 2. The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kogle Allé 6, DK-2970 Hørsholm, Denmark. Electronic address: atn@biosustain.dtu.dk.