The Sustainable Development Goals (SDGs) are an urgent call for action by the global community to address pressing problems associated with environmental sustainability and economic prosperity. Â As an iGEM team, we believe it is our responsibility to keep in mind these goals while designing our solution. Our project not only focuses on the goal of climate action by aiming to reduce greenhouse gas concentration in the atmosphere, but also seeks to promote responsible production by the design of a carbon neutral process for the production of industrially relevant compounds.
How it relates to their company:
We are aware of NTPC Limitedâ€™s commitment to sustainability and the environment and 'The Brighter Plan 2032â€™ to help accelerate actions taken to combat issues in these areas. We believe our project fits in well with these ideals. Our co-culture can act as a carbon sink, converting up to 80% of its absorbed carbon dioxide into sucrose to be used for the production of industrially relevant compounds. Further, we believe that in the future, it has the potential to be used to treat carbon dioxide emissions from power plants, thereby reducing the carbon dioxide emission intensity as it converts it into succinate.
S. elongatus is a photosynthetic cyanobacterium that naturally produces sucrose from light and atmospheric CO2 as an osmoprotectant to maintain its tonicity in a saltwater environment. We wish to engineer S. elongatus to continually secrete this sucrose out into the culture medium by means of a sucrose transporter. Lin et al. (2020) have obtained a high volumetric sucrose secretion productivity of 1.9 g/L/day in the same species.
Additionally, we wish to engineer E. coli to absorb and consume this sucrose from the medium as its sole carbon source. We also plan to engineer downstream metabolic processes in E. coli to redirect the carbon flux towards the production and secretion of Succinic Acid.
Thus, we will be converting atmospheric CO2 into a valuable metabolite, Succinic Acid, in a green and renewable manner, which is otherwise generated through greenhouse gas emitting processes that rely on petrochemical feedstocks.
Since E. coli is already a commonly used microbial cell factory for chemical synthesis, our biomanufacturing model essentially replaces the need to provide E coli with external sources of nutrition, by allowing it to consume sucrose produced by the photosynthetic cyanobacteria. With appropriate modifications in the E. coli module, our co-culture biomanufacturing model could potentially facilitate the synthesis of numerous other compounds, like biofuels and bioplastics, in a green and renewable manner.
Zhang et al. (2020) have made use of this same single step, one-pot, co-culture of S. elongatus and E. coli method to fix atmospheric CO2 to generate the valuable platform chemical, 3-Hydroxypropionic Acid.