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 which are either closed already or are closing up in the coming years and who stretch over great areas underneath the state of North Rhine Westphalia and the Saarland.
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 becomes a danger for the water supply if it doesn’t get pumped up before it rises up into the groundwater bearing layers. The water has a temperature of around 20°C and gets pumped into nearby rivers without further processing.
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 water 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 for a 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 levels of copper in the water are much lower than we expected from our own research and do not exceed any legal thresholds at the moment but this might change in the future when government thresholds get more restrictive.
Other metals like iron where present in levels suitable for our purposes of metal uptake and nanoparticle formation. Equipped with this knowledge and the offer of the RAG to supply us with water samples from iron contaminated sources we decided to dive deeper into the science of iron nanoparticle formation with the goal of developing novel materials with the added benefit of cleaning contaminated water sources found in our area.
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 environmental friendly 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.
NASA
At NASA scientists also think about the possibilities to use bacteria for biological remediation of metals. One of those scientists is Benjamin Lehner who works on the uptake of iron from moon and mars rock.
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.
