The group is also developing the means for large scale enzymatic synthesis of polysialic acid. In this context, both enzymatic steps - activation of sialic acid by CMP-sialic-acid synthetases (CSS) and polymerization by polysialyltransferases (PolyST) – will be combined to one reaction chain running in the same enzyme reactor. A very efficient protocol for the utilization of recombinant CSS has already been established. Current efforts within this project concern the adaptation of recombinant PolyST to an application in enzyme reactors.