Team:CSU CHINA
Clean
the Contamination
of Cadmium
CSU_CHINA
2020
the Contamination
of Cadmium
1
Environmental protectionhigh efficiency and tolerance
Most sewage plants are suitable for treating cadmium ions by physicochemical sedimentation. Still, it is easy to cause secondary pollution. For environmental principles, we used the synthetic biology method to redesign Synechocystis sp. PCC6803. It will effectively reduce the cadmium content after being put into the wastewater，and has high cadmium tolerance to be used for a long time.
Why Synechocystis
2
As one of the main prokaryotes on earth, cyanobacteria can effectively remove metal ions from wastewater, and there has been a large amount of literature investigating the resistance mechanism of cyanobacteria to cadmium ions, so we believe that it is relatively easy to modify it, and it has good adaptability to the water environment.
3
Extracellularchelation
In order to increase the absorption rate, we need to enrich the cadmium ions that are free in the water column around the engineered algae. Chelated proteins would be an excellent way to solve this problem. Upon successful expression, the cadmium ions will be taken up as much as possible into the cytoderm.
Transportation
4
When sufficient isolates are enriched in the cytoderm, more “pores” in the membrane are required to allow the cytosol to maximize cadmium ions’ uptake into the cell. After evaluating the source, efficiency, and specificity of the transport proteins, we consider expressing one or more highly efficient transport proteins to achieve this goal.
5
Chelate & Redox
For normal cells, the excessive absorption of Cd leads to a series of biochemical imbalances in the cell. In order to prevent cyanobacteria from premature death and lead to low cadmium uptake, or even release a large number of cadmium ions due to cell rupture, the specific protein was used as a chelating agent to bind cadmium ions in cells. REDOX proteins were also expressed to enhance anti-oxidative stress.
Reach for Perfection
6
We confine algae in Calcium-Alginate Microbeads, continuously expose them to blue light in a tube. Integrated with physical simulation, we extended the model level beyond biochemical reactions. Our team constructed a program using C# that simulates how cadmium, calcium alginate microsphere, PCC6803 cells interact with each other over a series of time steps.
7
SecurityAssurance
In order to avoid the possibility of Cadmium leak contaminating the environment, we designed Suicide Gene System When the engineered algae are irradiated by blue light, it will usually survive. However, once the cyanobacteria escape from the preset environment and out of the blue light, they will begin to secrete toxins and die.
The effectiveness of our Suicide Gene System is proven through the Safety model. Our model firmly proved our system’s ability to maintain regular cells’ sustainability and erase detached cells as expected.
The effectiveness of our Suicide Gene System is proven through the Safety model. Our model firmly proved our system’s ability to maintain regular cells’ sustainability and erase detached cells as expected.