This year’s Peking iGEM Team is trying to develop a highly efficient, low-cost and modularized biomaterial to deal with uranium pollution in the environment, using the methods of synthetic biology. Here we wish to share our experiences with safety control.
The hydrogel produced in this project is protein network secreted by genetically modified strains of host bacteria. The strains are restricted to the lab so that the cells produce the Uranium Reaper system continuously under rigorous control without any possibility for them to get into contact with the outside environment. Therefore, we have prevented recombinant DNA from flowing out into the environment. Even if a small fraction of bacteria leaked out, they would not express any protein without the induction with IPTG. Additionally, the bacterial hosts are laboratory strains which are likely to be highly uncompetitive compared wild bacteria in the outside environment.
During the utilization of the bio-functional hydrogel, uranyl ions are enriched to a high concentration, which is a potential cause for concern. However, the resulting high concentrations of ions are collected along with the bio-functional hydrogel for further processing. In this way, both the uranium and proteins are disposed of appropriately and do not remain in the outside environment.
The details are as follows:
We visited experts from the Peking University departments for Nuclear & Radiochemistry and Physics, respectively, to learn about the current situation surrounding uranium pollution in the real world and how people can control the situation. After finishing the main work, we presented them with the achievements of the project and got their feedback. (Learn more)
We should reproduce all of the experiments that we have done this summer to make sure the results are credible.
We will optimize the whole strategy to enhance the adsorption efficiency by changing pH, temperature, reaction time of crosslinking and recovery. (The efficiency is only about 60% without further optimization)
According to the results for the adsorption of 13nM uranyl, the hydrogel exhibited a good ability in a simulated seawater environment. We can thus also look into other usage scenarios of Uranium Reaper, such as bio-mining and uranium enrichment.
Exchange of the SUP module for other functional proteins. For example, we can integrate proteins which can bind other heavy metals such as mercury so that the hydrogel can be used to treat other kinds of pollution as well.
We can assemble enzyme systems behind the SpyTag backbone to create a production plant in vitro. In the protein hydrogel, the concentration of enzymes can be increased and the efficiency of biocatalysis may consequently also be enhanced.
If we optimize the number of SpyTag or SpyCatcher modules per protein monomer, as well as the working concentrations of proteins, we may make protein-3D printing using the Spy Crosslinking Network come true.
