Strategies to explore the potential of cyanobacteria for the production of essential amino acids

Cyanobacteria, also known as blue-green algae are the only prokaryotic organisms, which perform oxygenic photosynthesis like plants. They can be cultivated in freshwater as well as in marine water. 

Many cyanobacteria grow very fast and in contrast to eukaryotic algae some are able to fix atmospheric nitrogen. Large scale cultivation of cyanobacteria is already established in order to produce vitamins and essential fatty acids as dietary supplements for use in fish nutrition.   

Cyanobacteria produce the storage compound cyanophycin, a non-soluble polymer consisting of the amino acids L-aspartate and L-arginine. This polymer can be used in different ways, such as the isolation of pure L-arginine. In the current project we have studied basic characteristics of cyanophycin production by cyanobacteria. Further, we have established a photosynthetic production strategy for this biopolymer.

Following results have been achieved:

• Construction and characterization of two cyanobacterial production strains for cyanophycin
• Establishment of a new photobioreactor design for cyanophycin production with yields of 1 gram cyanophycin per liter of cell culture 
• Construction and characterization of a cyanobacterial production strain for glutamine
• Establishment of a PCR-based system for the detection of bacterial contaminants
• Transcriptomics of regulatory systems in the cellular response to nitrogen availability

Based on our interdisciplinary approach which included expertise in biochemistry, molecular biology, microbiology and process optimization we were able to establish a very efficient production system for the biopolymer cyanophycin.