Polysialic acid (polySia) is a carbohydrate polymer of varying chain length. It is a promising scaffold material for tissue engineering. In this work, high chain length polySia was produced by an E. coli K1 strain in a 10 L bioreactor in batch-and fed-batch mode, respectively. A new downstream process for polySia is presented, based on membrane adsorber technology and use of inorganic anion exchanger. These methods enable the replacement of precipitation steps, such as acetone-, cetavlon-and ethanol-precipitation of the already established purification process. The purification process was simplified, while process efficiency and product qualities were improved. The overall yield of polySia from a 10 L batch cultivation process was 61 % and for 10 L fed-batch cultivation process 40 % with an overall purity of 98 %. The endotoxin content was determined to be negligible (14 EU mg -1 ). Th e ma i n advantage of this new downstream process is that polySia with high chain length > 130 DP (degree of polymerization) can be obtained. In fed-batch cultivation chain lengths up to 160 DP were obtained.

No abstract