Our Project

With rising atmospheric CO₂ concentrations and declining oil reserves, we saw that the worldwide effort to change from a petroleum based industry to a carbon neutral industry needs to increase drastically. One of the most promising key technologies right now is the use of phototrophic organisms for biotechnological applications. Hence, we decided quite early this year to devote ourselves to a photosynthetic project. During the design phase, which we initially thought about a project around the model moss Physcomitrella patens, we soon stumbled upon many common obstacles characteristic to phototrophic chassis due to our choice of organism. Issues like time intensive culturing and complicated techniques to perform basic molecular biological methods eventually showed us, why only very few iGEM teams every year decide to use a phototrophic chassis. We saw a need to tackle these issues and were determined to find a solution. Consequently, our choice fell on the cyanobacterial strain Synechococcus elongatus UTEX 2973, due to its highly potential doubling time of about 2 hours ¹. This could have a huge impact, as the time consumed by many workflows is mainly dictated by the growth of your chassis. Our strain could compete with common heterotrophic chassis like yeast, which would be a novelty in photosynthetic research. We are dedicated to develop this strain as a chassis for the scientific community and future iGEM teams. To restore its natural competence, which it has lost after isolation, we will integrate a CRISPR/Cpf1 system into our toolbox, enabling easy genomic manipulation and thus giving us the tools to construct various strains and revert the point mutation responsible for the loss of natural competence. Additionally, we remove the wild type plasmid pANS from Synechococcus to use it’s origin of replication in our “Marburg Collection 2.0”: a versatile Golden Gate based modular cloning library for fast state of the art assembly of genetic constructs based on a “one step - one pot” reaction. By designing “operon connectors”, our toolbox is the first to assemble complete operons in the span of two days. This assembly technique can be performed in our open source liquid handler OT-2 from Opentrons, paving the way for our vision of fully automated cloning in molecular and synthetic biology - from ordered primers to the finished construct. To add to this vision, we are the first to establish several laboratory practices in this robot such as colony picking, plating and plasmid purification. By making full cloning processes possible in the Opentron environment, we give iGEM teams access to an affordable way to accelerate their undertaking, allowing them to allocate more time to the design of their project. In our metabolic engineering project we prove the value of the tools we hereby provide: Using our cloning system, we modify our established chassis to produce limonene and farnesene, two valuable biochemicals that can be used as a biofuel. The chassis’ capabilities are not limited to terpene production but can be expanded to other areas of biotechnological applications as well as to academic experimental setups. Customized strains offer the opportunity of sustainable growth in drug development and manufacturing, helping us all to achieve our vision of a more sustainable future on this planet.

¹ Yu, J.; Liberton M.; Cliften, P. F.; Head, R. D.; Jacobs, J. M.; Smith, R. D.; Koppenaal, D. W.; Brand J. J.; Pakrasi, H. B.: Synechococcus elongatus UTEX 2973, a fast growing cyanobacterial chassis for biosynthesis using light and CO₂. Scientific Reports. 5:8132. DOI: 10.1038/srep08132 (2015)