Short Summary
Intense mining in Germany causes mine drainage with high potential to contaminate fresh water. We cooperated with leading experts including environmental coordinators, Germany’s biggest mining company (RAG), water quality specialists, and environmental chemists. While exploring solutions, we identified mine drainage as a rich source of valuable metals. Due to dwindling resources and increasing demand we engineered bacteria for environmentally friendly/ecofriendly recycling of these metals via scavenging into nanoparticles. A NASA associate pointed us towards ferritin, a metal binding protein. Collaborating with the RAG during our project, we discussed the impact of iron and copper on fresh water quality as well as requirements for a device capable of filtering mine drainage. In close contact with an expert on copper biochemistry, we developed a functional system for copper uptake – unprecedented in the iGEM community. Through continuous discussions with various stakeholders, we identified printing acquired metals as a promising application.
Ruhrkohle AG (RAG)
Searching for a possible source of metal ions we contacted the Ruhrkohle AG (RAG) which is Germany's biggest coal mining corporation. The RAG is responsible for taking care of all the coal mines who stretch over great areas underneath the state of Saarland and North Rhine Westphalia where our University is located.
One of the major tasks of the RAG is to pump up groundwater which seeps through different layers of rock and floods the coal mines. This water is getting contaminated with heavy metals and threatens to pollute water supplies if it is not pumped out before rising into the groundwater bearing layers. The water has a temperature of approximately 20°C and depending on its quality is either further processed by removing iron or just gets dumped directly into rivers.
Figure 1: Team members visit experts at the coal mine in Prosper-Haniel, NRW, Germany from left to right Christoph Geske, Levin Joe Klages and Johannes Ruhnau.
Because information about the exact mining drainage composition is not easily accessible we contacted Dr. Michael Drobniewski who is the Director of Operation of the Mine Water Management Division at the RAG. He gave us valuable information about the water composition and invited us to a personal meeting.
Figure 2: Meeting with Dr. Michael Drobniewski, director of operations of the ‘Mine Water Management Division’ in the ‘Technical and Logistics Services Division’ at the RAG AG.
In our meeting we learned that the high levels of iron in the mine drainage of up to 41 mg/l is one of the issue the engineers at RAG have to deal with. Currently the RAG uses precipitation medium and special facilities to remove iron from the mine drainage.
Equipped with this knowledge and the offer of the RAG to supply us with samples of mining drainage containing high amounts of iron and copper we decided to dive deeper into the science of iron and copper nanoparticle formation.
Our goal of developing novel materials with the added benefit of cleaning contaminated water sources found with the RAG an important partner to bring us closer to our goal of exploring mining drainage as a source for valuable metals.
National Aeronautics and Space Administration (NASA)
At NASA, scientists also think about the possibility to utilize bacteria for the purpose of biological remediation of metals. One of those scientists is Benjamin Lehner who works at NASA on the uptake of iron from moon rock which could be used to produce electronics in the future.
Figure 3: Skype call with Benjamin Lehner, PhD Exchange Candidate at the NASA Ames Research Center in California, Silicon Valley.
We talked with Benjamin about our project idea, possible bottlenecks and how NASA and iGEM work together. Thanks to his great insights we learned that the uptake of iron ions in high amounts by bacteria is possible and that printing with iron in space is currently a field NASA is working on. He explained to us, that iron can be used in the construction of conducting structures when used in an air free atmosphere for example on the moon. This changed our assumptions on which metals can be used for printing conducting structures and we decided to add iron to the list of metal ions we could use for our printing applications. His encouraging remarks about the possibility to import very high amounts of iron ions into cells gave us the confidence to further pursue our work in the direction of iron uptake with the help of modified ferritin. By also focusing on iron uptake we add another important metal to the list of materials which can be found in elevated levels in pit water all over Germany.
Mr. Lehner also encouraged us to continue our work on copper uptake because to his knowledge 20% of the global copper mined and recycling is already done with the help of bacteria and it’s an essential metal required in many industrial applications.
He also recommended us to get in contact with Jon Marles-Wright which is an expert in the field of ferritin and its possible applications.
Physics Department and Nanoparticle Experts
To gain valuable insight about physical characteristics of our nanoparticles we stood in close contact with the physics department here at our university. By granting us access to measurement equipment like an electron microscope and through a constant dialog with the department we were able to attain a new level of understanding about our nanoparticles.
Beside the expertise and advice on how to deal with nanoparticles we made extensive use of multiple TEM microscopes which require an experienced operator who spend long hours helping us to load the probes inside the vacuum chamber and set up the TEM correctly.
Figure 4: Matthias Otto visiting the 200kV TEM at the physics departement at the University Bielefeld.
Ferritin Experts
Ferritin is a capital field of research and it is hard to get a grasp of all the possibilities this amazing protein presents. Jon Marles-Wright which is also affiliated with the Newcastle iGEM Team was a great help in this regard and described to us in the optimal practices in the lab regarding our ideas with ferritin.
Figure 5: Jon Marles-Wright expert on ferritin and also affiliated with the iGEM team newcastle.
His detailed description on how he purifies ferritin in his lab and how to increase the yield were much appreciated and helped us to improve on our first purification approaches. Via his technique which is quick and easy we purified our ferritin for further use in gold and silver nanoparticle formation.
Prof. Dr. José Argüello Copper Importer Expert
Prof. Dr. Jose M Argüello is a professor at the Worcester Polytechnic Institute (WPI). His main field of science is the homeostasis of micro nutrients as in prokaryotic systems.
We found out about him by doing research on HmtA (BBa_K2638000) and finding a bachelor thesis written by Yi Sun. This bachelor thesis was approved by Prof. Dr. Jose M. Argüello.
We contacted him to ask him for advice on copper transport systems and he advised us during an E Mail exchange to use OprC (BBa_K2638200) from Pseudomonas aeruginosa if we want to import copper ions from the surrounding media. As shown on our copper accumulation . Moreover he sent us important literature and models that we could implement into our modeling.
