Phototrophic biofilms produce a matrix of extracellular polymeric substances (EPS), which holds the cells together and functions inter alia as nutrient storage and protection layer. EPS mainly consist of water, polysaccharides, proteins, lipids and nucleic acids. Additionally, EPS contain media components, lysis and hydrolysis products which makes the composition very complex. Thus, rough simplifications are used and commonly one or at most two components of the EPS are examined. This is, despite the fact, that conclusions can be drawn about the state of the biofilm or the biofilm stage via the composition of the EPS. In this work a new method   for separation and analysis of EPS in the main components (i) polysaccharides, (ii) proteins and (iii) lipids is presented with recovery rates of nearly 100 %. The method was established with synthetic EPS, which based on the composition of real EPS described in literature. Afterwards, the method was transferred to real EPS samples and the composition of EPS-extracts from Trichocoleus sociatus, cultivated under heterotrophic and mixotrophic batch and fed-batch conditions, was analysed over the cultivation period. It was observed that mixotrophic cultivation led to higher amounts of carbohydrates, lipids and proteins than heterotrophic cultivation respectively, regardless of batch or fed-batch culture. While the amount of proteins increased during the cultivation period, carbohydrates and lipids were dominant in the beginning and decreased afterwards.

D. Strieth, A. Schwarz, J. Stiefelmaier, N. Erdmann, K. Muffler, R. Ulber; New procedure for separation and analysis of the main components of cyanobacterial EPS; Journal of Biotechnology (JBIOTEC-D-20-01441R1) im Druck