Perchlorate salts are found in the Martian regolith covering the surface of Mars at a concentration of up to 1 %. Perchlorate is a highly oxidising compound used in rocket fuels and munitions. It is dangerous and toxic to humans. Current disposal methods are via expensive bioreactors, or contained explosions. So, if humans are to colonise Mars, we will have to remove the perchlorates from the soil in order to have a chance of developing agriculture for our survival. The University of Exeter 2018 iGEM Team are developing a bioreactor that will remove perchlorate salts from soil, and dispose of waste perchlorate in a cheap, safe manner, by using genetically engineered bacteria with (per)chlorate and chlorite reducing enzymes.

To assist their project, we have recorded the affects of perchlorate on the growth of our free-living nitrogen fixing, soil bacteria. This has helped show the importance of their project in aiding the development of agricultural methods on Mars, as well as disposing of perchlorate in a safe, contained way so as not to harm the environment and affect soil ecosystems. The results of our experiments are displayed in Figures 1 to 3.

Figure 1. Azorhizobium caulidolens grown in LB broth containing NaCIO₄ at varying concentrations. Cells were grown in 96-well plate format in 200 µl volumes at 30 °C over 24 hours. (n=3 replicates, error bars are standard error of the mean).

Figure 2. Azospirillum brasilense grown in LB broth containing NaCIO₄ at varying concentrations. Cells were grown in 96-well plate format in 200 µl volumes at 30 °C over 24 hours. (n=3 replicates, error bars are standard error of the mean).

Figure 3. Herbosporillum seropedicae grown in LB broth containing NaCIO₄ at varying concentrations. Cells were grown in 96-well plate format in 200 µl volumes at 30 °C over 24 hours. (n=3 replicates, error bars are standard error of the mean).

One of our team members has a friend at Sorbonne, who kindly put us in contact with their iGEM team. As they knew we have architecture students in the team they asked us to produce a visual for their human practices. They sent us over an initial sketch, once this was received we used our imaginations and attempted to visualise this part of their project for them. The image shows a semi-permeable membrane which would contain their genetically modified bacteria, anchored to the sea bed - but not so deep that they wouldn’t receive any light. This would prevent their bacteria from being released into the environment.

To aid Warwick in their project we collected a series of water samples from bodies of water in areas surrounding Newcastle.