Bacherlor Thesis/Master Thesis: Space biomining - cultivating anaerobic microorganisms with electricity to extract iron on Mars
In a few decades, humans will probably be sent to Mars to explore the red planet. To make the exploration sustainable, astronauts will need to rely on the local resources of Mars, i.e. in situ resource utilization (ISRU). The Martian regolith is rich in metals, especially iron, which could be used to produce steel and build habitats. However, conventional steelmaking is based on the use of fossil fuels and unlimited energy, which are lacking on Mars. Therefore, novel methods are needed to produce steel on Mars and reduce CO2 emissions on Earth. In addition, the Martian regolith has a complex chemical composition, which further complicates the extraction of iron.
Some microorganisms, known as iron-reducing bacteria and archaea, can dissolve iron oxides (ferric minerals found on Mars) through cellular respiration. These anaerobic microorganisms can be used for biomining, i.e. the biological extraction of metals. They are also known in the field of electromicrobiology for their ability to interact with electrodes, meaning that they can feed on electricity in an electrochemical cell to power their cellular respiration (Microbial Electrochemical Technologies). In this project, we are using iron-reducing microorganisms to extract iron from minerals, with only electricity and carbon dioxide as substrates (electroautotrophic metabolisms). Such microbial electrochemical systems have not been studied before and could be advantageous on Mars where energy and resources (food) are scarce.
During the internship, anaerobic microorganisms, including thermophiles from hydrothermal vents, will be cultivated both with standard anaerobic techniques and in electrochemical reactors. The goal will be to evaluate the capacity of the reactors to reduce and transform minerals when different parameters are changed: microbial species, minerals (iron oxides or Martian soil simulant), electrode potential… Growth will be monitored through microscopy, cell counting, organic acid production (HPLC) and possibly qPCR. Iron reduction will be studied with the ferrozine assay (spectrophotometry) and possibly XRD and SEM. Basic electrochemical methods, i.e. chronoamperometry and cyclic voltammetry, will serve to understand the use of electricity by the microbes. This project requires a background in microbiology, as well as a strong motivation to work on interdisciplinary research (electrochemistry, geology…), within an international team.
Period of time:
Dr. Guillaume Pillot – pillotprotect me ?!uvt.uni-bremenprotect me ?!.de
M.Sc. Antoine Carissimo – carissimoprotect me ?!uvt.uni-bremenprotect me ?!.de