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Courtesy of Mike Allen and Steve Gschmeissner

Production scale up of a thermotolerant C-phycocyanin from a mesophilic cyanobacterial bio-platform (IBioIC supported)

Principle investigator: Alistair McCormick
University of Edinburgh

The colour of a product plays a key role in its market success. Consumer demand is currently driving the replacement of artificial colourants with naturally sourced pigments, particularly in the food and beverage industries. Compared to all other colours, materials to make blue pigments are relatively rare and historically have been the most challenging to source. To date, the sole commercial source for natural blue pigments is the protein C-phycocyanin (CPC) from the cyanobacterium Arthrospira platensis (Spirulina). Spirulina is relatively simple to culture and grows well under near ambient temperatures and low levels of light. But compared to artificial colourants, CPC from Spirulina is unstable and prone to discolouration outside of a relatively narrow range of temperature and pH conditions, which limits its industrial applications and increases production costs. More stable forms of CPC do exist in other microalgae (e.g. thermophilic species) but these strains have significant barriers for industrial uptake, such as slow growth and a need for specialised culturing conditions. Recently, we have generated a strain of the model cyanobacterium Synechocystis sp. PCC 6803 called O-Te that grows rapidly under similar conditions to Spirulina but produces a thermotolerant version of CPC from the thermophilic cyanobacterium Thermosynechococcus elongatus (Te-CPC). Te-CPC remains blue at 60 ºC, and furthermore can renature (i.e. the blue colour returns) when cooled after exposure to higher temperatures. Thus, Te-CPC offers many opportunities for significantly expanding the commercial applications of CPC, including High Temperature/Short Time (HTST) pasteurisation (i.e. for perishable beverages such as juices, beers, dairy products) and confectionaries cooked at >80ºC for extended periods. In this POC study, we will test for and aim to mitigate any potential barriers to producing TE-CPC by examining 1) our capacity to replicate lab-scale performances at larger culture volumes 2) if processing methods for CPC from Spirulina biomass readily translate to Te-CPC from O-Te biomass. ScotBio will then perform quality control and performance testing on Te-CPC to validate commercial readiness.