Proof of Concept
Proof of Concept
The ultimate goal of our project is to use the modified Synechocystis sp.PCC6803 in Cadmium-polluted water. Through a lot of laboratory work, we have proved that Synechocystis sp.PCC6803 and the modified E. coli can effectively remove cadmium from the culture medium. To further validate and explore the possibility of its use in the real world, we designed liquid media with different cadmium concentration gradients to investigate the cadmium tolerance of E. coli expressing MntH & TMCd1 & APX2 and determined its cadmium uptake capacity in liquid media with a cadmium concentration of 0.1 mg/L. The results showed that our engineered E. coli have high cadmium tolerance (figure1). Its ability to remove cadmium is significantly improved (figure2).
Figure1: Growth curves of the modified E. coli at different cadmium concentrations.
Figure2: Cadmium uptake curve of the modified E. coli.
What’s more, we validated the cadmium uptake of Synechocystis sp.PCC6803 in a similar liquid media and explored the effectiveness of Calcium-Alginate Microbeads (Ca-Alg MBs）in real-world environments. The results show that our algae have a particular ability of cadmium uptake and cadmium tolerance and can be significantly enhanced by the action of Ca-Alg MBs (figure3/4).
Figure3: Cadmium uptake curve of Synechocystis sp.PCC6803 and the effect of Ca-Alg MBs on the ability of it to absorb cadmium.
Figure4: Protective effect of Ca-AIg MBs on algal growth in high cadmium environments(0.1mg/L, left) and (2mg/L, right).
In conclusion, the results indicate that our design could help prokaryote survive in cadmium-polluted natural water bodies and effectively remove cadmium, which may be applied in the natural environment and play a vital environmental protection role.