Team:UrbanTundra Edmonton/Description
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Background
Sustainable Living on Mars: Remediation of Martian Soil to Produce Oxygen
In 2008, the Phoenix Mars Lander detected perchlorate (ClO4⁻) in Martian regolith at a concentration of 0.5% - 1.0%, up to 10 000 times higher than that on Earth. Perchlorate is a chemical anion that has adverse health effects on humans, rendering Martian soil unfarmable and posing a challenge to any future pursuits at colonization. The main sources of exposure to perchlorate on Mars would be through the inhalation of dust and the ingestion of contaminated food/water. Once it enters the body, its primary target is the thyroid gland, which regulates the body’s metabolism. ClO4⁻ directly competes with the uptake of iodine ions by the thyroid, leading to decreased hormonal output, slowed metabolism, and the hindered function of many organ systems. If colonization on Mars is to be made possible, detoxifying the soil of perchlorate is a necessity.
When we dug deeper, we stumbled on the work of Davila et al [1]who proposed that the toxic concentration of ClO4⁻in Martian soil was actually a resource that could be exploited both as a source of rocket fuel and O2, while remediating the soil in the process. It can be broken down further into perchlorite (ClO2⁻), chlorine (Cl-), and oxygen (O2) using two already sequenced enzymes, perchlorate reductase and chlorite dismutase.
Ideonella dechloratans
Ideonella dechloratans, one of the many perchlorate reducing microorganisms, is the species in which we focused our investigations on. I. dechloratans utilizes two enzymes, Perchlorate Reductase (Pcr) and Chlorite Dismutase (Cld), to convert perchlorate ions to chloride ions and oxygen gas (http://aem.asm.org/content/78/12/4380.full). As of now, only Cld has been successfully expressed by other scientists. Throughout the summer, we focused on taking the latter half of this perchlorate reducing pathway, the one involving Chlorite Dismutase, and transforming it into E. coli to explore its effectiveness towards the biodegradation of martian perchlorate as an effective tool for oxygen production.
Our Goal
Our goal was to take this perchlorate reducing pathway and to transform it into E. coli in order to effectively use it to remediate Martian regolith for use in a Martian colony. We want to show that Chlorite Dismutase, when expressed in an E. coli chassis, is functional in regards to the conversion of chlorite ions into both oxygen and chloride ions. Our project is essentially a proof of concept, showing the viability of using biological systems as a method of oxygen production.
Why?
Stephen Hawking recognized that humans are like eggs in a basket - drop the basket and all is lost. Planet Earth is the basket, and over the long-term, a calamity - be it through climate change, disease, asteroid collisions, etc. - is a statistical certainty. Colonizing Mars is the first step in distributing the ‘eggs’ to other baskets. Interest in the space industry has been growing, thanks in part to films like Interstellar and The Martian. Organizations such as NASA and SpaceX have planned for a manned Mars mission by 2035 and 2025 respectively. Elon Musk, CEO of SpaceX, even expressed his hopes of establishing a Martian colony in our lifetime. However, colonies must be able to sustain themselves on what can be found locally. There isn’t much on Mars, but there is perchlorate, and that is why we feel that this project and others like it will contribute significantly to what is evolving into a major international effort. In the short term, Mars missions will develop, and spin-off a range of creative technologies that will allow us all to live more comfortably, efficiently, and cleanly on planet Earth. In the long term, humanity’s aspiration to reach out and conquer the stars will finally become a reality.
