We are a team of budding, young scientists from the University of Exeter, UK competing in a worldwide synthetic biology competition called iGEM.

The aim for the competition is to address a problem facing the world using synthetic biology – taking advantage of biological systems for useful purposes.

This year our project aims to produce oxygen from a toxic compound called perchlorate using genetically engineered bacteria.

Perchlorate is used in rocket fuel and can contaminate water and food, with potential harmful effects, especially on unborn children. It is also found abundantly in Martian dust and dirt (regolith). 

We are working on a bioreactor that could use these bacteria to produce breathable oxygen and arable soil.

We’ll be travelling to Boston, USA for the competition Jamboree.

We'll be answering questions on Thursday and Friday (27th-28th Sept). ASK US ANYTHING!!!

We can be found at:








Comments: 76 • Responses: 32  • Date: 

Paralytic71319 karma

What has been done that allows for this theory to be possible? As in, why do you think turning Perchlorate into Oxygen can be done?

ExeterUniIGEM7 karma

We want our bacteria to produce perchlorate reductase (which makes perchlorate into chlorite) and chlorite dismutase (which makes chloride and oxygen). There are actually bacteria that produce these enzymes in nature, but we're hoping that E. coli will produce more enzyme because it generally grows faster. It also allows us to mix and match DNA coding sequences (so we can produce the perchlorate reductase from one bacterium species and the chlorite dismutase from another) from different bacteria to see what would be faster.

So it's definitely possible!

Paralytic7133 karma


But seriously, thanks for the reply and I hope your results are even more successful than you hoped for.

ExeterUniIGEM2 karma

Haha! I'm actually a physicist so that was me when we started this project 3 months ago ;)

Perchlorate reductase and chlorite dismutase are enzymes (which allows chemical reactions that normally would not occur, to occur or go faster). Other people have managed to figure out which specific DNA pieces need to be in the bacteria for these enzymes to be produced. We then take these DNA pieces and through some biology magic we can put the DNA pieces into our bacteria and therefore they will also produce those enzymes.

Hope that might have cleared some stuff up!

kyleb3503 karma

I'm curious to know HOW it can be done.

ExeterUniIGEM4 karma

Essentially, we're using enzymes produced by a few specialised bacteria to break down perchlorates. The first enzyme is perchlorate reductase, which catalyses the reaction below

ClO4 + 2AH2 -> ClO2 + 2A + 2H2O

(Here, A could be a variety of different chemicals found in the cell, usually some sort of quinone)

Then, chlorite dismustase will catalyse

ClO2 -> O2 + Cl-

This is the chemical pathway we would hope to use in making oxgyen from Martian perchlorates.

butsuon0 karma

I was thinking something similar just off reading the title. Sure, maybe through a complex (and probably dangerous) chemical reaction they could produce oxygen from perchlorate in sufficient volumes. (That's not what they're doing)

I can guess their process produces CO2 as a byproduct and then that CO2 is captured for use in agriculture. However, you still have to produce sufficient volumes of Nitrogen and Hydrogen to produce breathable air.

I can't imagine their process is sustainable without rather extreme energy resources.

ExeterUniIGEM2 karma

You can actually reduce perchlorate chemically, but it is explosive as you said.

CO2 is not actually a byproduct of our process! The martian atmosphere is ~95% CO2 so there is plenty of that. Our goal is not to produce breathable air either, it's just to produce oxygen. Which has mutiple uses, not just breathing. It's also used as the oxidizer in rocket fuel.

Currently the only energy use is a propeller to move liquids around in our bioreactor :)

But the project is definitely still a work in progress

butsuon0 karma

So what's the end-goal of the project? Rocket fuel production on the surface is probably one of the least important projects of utilizing the martian surface.

For example, maintaining an environment where you bioreactor can exist in the first place. How does your bacteria handle the intense heat and radiation on the surface of mars? At what temperature does your bacteria die or go into stasis? How resilient are they to DNA damage from radiation?

The reaction is very cool, but you're gonna have to jump through some serious hoops to convince people it's valuable.

ExeterUniIGEM2 karma

For a long lasting colony rocket fuel production is also important. It was just an example that oxygen can be used for multiple things. Bacteria is not at all resistant to damage from radiation and would most likely (hopefully) die when exposed to it. This is actually one of the fail safes when it comes to contamination. Any bacteria escaping the reactor would die. To protect the bioreactor we're planning on using a high Z composite metal foam.

Might be! But we're definitely not at a stage of trying to sell this to anyone, we're still trying to see if it will work well, and then it can be compared to other methods of producing oxygen in-situ.

love_me_please7 karma

How are you getting the bacteria modified, does that happen on site?

As a bonus follow up question, what's your favourite pizza from the Firehouse Pub in Exeter?

PGteamGB4 karma

Firehouse... what a place!

ExeterUniIGEM3 karma

I know! I'm going again next week and can't wait!

ExeterUniIGEM3 karma

We do modify our bacteria on site, yes! We know which specific DNA sequnces correlate to production of the enzymes we want the bacteria to produce so we order those from a company that makes them for us.

We prep our bacteria to make them receptive to taking in DNA and then we add the DNA in. The specific type of bacteria we're using is really good at taking in DNA and then producing the proteins corresponding to that DNA sequence.

Hm, that's a difficult one. I'm quite partial to the vegan classic to be honest. I just really love mushroom.

Ghonaherpasiphilaids7 karma

Why bother posting this today if you're not going to answer questions until tomorrow and the next day?

dinoshaw53473 karma

So that by the time he can read it he doesn’t have to wait a while for responses

ExeterUniIGEM4 karma

We just wanted a day or so for people to think about questions! And btw, we are both ladies :)

Almostcrimson5 karma

Are you able to quantify how much oxygen can be produced by the bacteria. Like how efficient the process is. Have you done work on the type of deployment mechanism will be used to start the process?

ExeterUniIGEM3 karma

If we have a perchlorate concentration of >1000 μmol/m^3 the bacteria should be able to produce 6.43μmol/m^3 per second. Assuming that we can keep the perchlorate concentration reasonable constant.

I'm not quite sure what you mean by deployment mechanism though? We mix martian soil and water, filter out the big bits of soil and then we put our bacteria in.

loromondy4 karma

Interesting idea, from the perchlorate you can get two oxygen molecules but what is the bacteria going to do with the Chlorine? Also oxygen and chlorine are pretty reactive elements, how's the bacteria going to protect itself from such harsh environment?

ExeterUniIGEM4 karma

The bacteria don't do anything with the chlorine actually. Perchlorate exists as salts (eg. MgCl4) and the chloride will react with the ions present in the water from these salts.

As for the oxygen, we're more concerned that the bacteria might use the oxygen for itself instead of releasing it into the solution. We're currently working on an experiment that hopefully shows that they release it though!

loromondy3 karma

Cool, I'm usually rooting for my local IGEM team (University of Delft) but I'll keep an eye on you! Lots of luck

ExeterUniIGEM2 karma

Delft has done quite well in recent years if I remember correctly! They're doing a project on doping, right? I look forward to seeing them in Boston :)

curryandanahn3 karma

What processes will your bioreactor do to the soil to make it into oxygen? What parts does it have and what do they do? What security mechanisms do you have in place to stop bacteria from getting out and killing all the innocent Martians?

ExeterUniIGEM3 karma

We're mixing the soil with water, because perchlorate is water soluble. Then we filter out all the big soil particles. We have bacteria that produce the enzymes perchlorate reductase (makes perchlorate into chlorite) and chlorite dismutase (makes chlorite into oxygen and chloride). The bacteria will be sitting inside little beads, that are passed through a vortex bioreactor. This means that it has a propellor that creates a tiny vortex, which sorts out lighter particles (e.g oxygen) into a separate tube.

Contamination control is of course an issue! In case things go wrong we're going to pass copper beads through the bioreactor. And as a failsafe the bacteria we're using are not at all resistant to UV radiation, which there is plenty of on Mars. So if the bacteria were to get out they would die pretty darn quickly.

If there is indeed life on Mars it's also somehwat questionably to colonize it in the first place. What gives us the "right" to gallivant around the universe assuming we can just settle on other planets?

So before we go to Mars there are a fair few ethical issues to resolve!

londons_explorer3 karma

If mars has ice or water, surely producing oxygen by electrolysis of that water is a much better approach, with far more developed technology and lower risks?

Oxygen can also come from atmospheric CO2, either using biological processes (algae), or electrolysis. Using atmospheric CO2 has the advantage that the whole process could be automated and work without humans being present.

With so many well-known ways to make oxygen from martian resources, why is there a focus on even more approaches?

ExeterUniIGEM2 karma

If I remember correctly NASA is actually sending up a rover in 2020 with the MOXIE system on it which uses atmospheric CO2 to produce oxygen.

The liquid water they've found on Mars actually has a lot of perchlorate salts in it!

Our thinking was to use something that isn't a useful resource on Mars to make oxygen, so we'd get rid of toxic perchlorate and produce oxygen, 2 birds with one stone.

drinkmorecoffee3 karma

When you succeed, will we have to start labeling Earth oxygen "Organic"?

ExeterUniIGEM6 karma

Thanks for having such faith in our project!

Might be more useful to label oxygen produced by our bioreactor as GMO, because I'm not sure all oxygen on Earth would meeet organic standards. Is it organic if it's produced by plants that aren't grown organically?

Edit: on to in

PGteamGB3 karma

This is awesome, best of luck to you guys! I graduated from Exeter in 2010 and now live in Boston.

What is the probability of your experiment being successful?.. and what implications would that have for further research?

ExeterUniIGEM2 karma

How cool! How are you finding it?

Currently we're pretty hopeful! We have managed to produce oxygen from chlorite (one step in the process). We've had some difficulty getting the bacteria to express the other enzyme in the process, as the DNA coding sequence for it is quite big! But we're pretty sure we'll get there.

Currently there are no plans for further research into this particular topic after the presentation in Boston. We all have to get back to normal student life eventually.

If we had more time we would of course try the next step and see how much oxygen we can produce with the bacteria in the bioreactor, and if that was promising it might be something to take to NASA or the ESA! But I'm getting a bit ahead of myself. Due to the short time span of the project we won't have time to put our bacteria in the bioreactor even.

Frohling132 karma

Which organism are you using?

How big is your prototype going to be?

And how much are you looking forward to the jamboree and the wiki-freeze?

Greetings from a 2017 iGEM participant.

ExeterUniIGEM2 karma

We are transforming a strain of E.coli called BL21DE3 which I think you guys used last year. The DNA for the chlorite dismutase and the perchlorate reductase I believe has come from a perchlorate reducing bacteria called A.suillum.

Our bioreactor prototype should be around 2x.33 metres.

We are generally on top of the Wiki and Prof. Love said we are right on time if not a little ahead so it SHOULD be fine (fingers crossed). We are all very much looking forward to the Jamboree and travelling to Boston in general, just picked out our presenters!

Thank you for asking us questions!

UniversalUsername2 karma

What are the system inputs and outputs?

E.g soil, power into o2? Are you feeding the o2 into a tube or something?

ExeterUniIGEM3 karma

Input is martian soil and water. We're planning to put our bacteria into beads and then passing everything through a vortex bioreactor which can sort out oxygen and pass it into a separate tube. We do need to power the propellor as well.
Outputs are O2 and chloride salts, which can actually be used to make the beads that we put the bacteria in.

EKTorrence2 karma

What sort of transport requirements would the bacteria have? How much equipment does the process require?

ExeterUniIGEM2 karma

We are working with NASA as a stakeholder to hypothetically fit our bioreactor into a system of their own, should it come to that. It would be frozen on the way there and then defrosted for activation once arrived.

The equipment mentioned is merely the bioreactor of our design, with specifications of 2 x .33 metres.

I hope this answers your question!

Edit: A space

crosleyxj2 karma

Is your project to design a mars-compatible bioreactor for a known process or are you inventing the entire process?

ExeterUniIGEM2 karma

We are inserting DNA into E.coli from bacteria that are known to perform this process, however the process has not been shown to work in E.coli, and we are having to manipulate and simplify some of it's mechanisms.

We're using E.coli, as the native perchlorate-reducing bacteria grows rather slowly and in a peculiar environment. Additionally, it is not very well researched. Using E.coli gives us far more control over what happens as its a model organism.

Our bioreactor design is also completely invented by us although we have taken advice from several academics and taken into consideration other bioreactor designs for similar processes. I hope this answers your question!

BeardySam2 karma

Do you have an idea for the biological mechanism you want to breed or is this a sort of genetic Monte Carlo ?

ExeterUniIGEM2 karma

Definitely not just guesswork. The enzymes that reduce perchlorate into oxygen are studied and we have the DNA sequences that lead to these enzymes being expressed in the bacteria. We even have bacteria expressing one of the enzymes, and we're well on our way for the second one!

SCD5922 karma

Do you think we really have any hope with saving our polluted planet?

I'm not being cynical, I really hope?

ExeterUniIGEM3 karma

I don't think you're being too cynical. The current politcal climate is not looking great in regards to climate change for example.
I definitely think there is hope, but I also think that we need to get it together. There has been a huge push to end single use plastics, but I think we need a similar collective push and drive to take care of the environment in general. However, what is "good" for the environment and what is not is often complicated and sometimes counterintuitive, so I think that's going to be a lot harder.

DigiMagic2 karma

Out of all the oxygen in the martian soil, how much of it is in perchlorates and how much is in iron rust and other minerals?

ExeterUniIGEM2 karma

We know that the perchlorate concentration is 1%, but I must admit that I really don't know how much of the oxygen in the soil is in different forms.

Aradoris2 karma

How long would it take and how much soil would be needed to convert Martian soil to an atmosphere that could support life?

ExeterUniIGEM3 karma

Our goal isn't actually to terraform Mars. Due to its weak magnetic field any atmosphere is very vulnerable to solar winds.

We're just planning on producing oxygen for the people that might inhabit the planet.

pringlescan51 karma

What other steps would need to be taken to make the soil arable, or is removing percolate the only major issue?

ExeterUniIGEM3 karma

You can actually grow plants in soil with perchlorate, it's just that eating those plants can disrupt thyroid function.

But as far as I'm currently aware, perchlorate is the only major issue.

Zap_Franka1 karma

How can we fix Earth first?

ExeterUniIGEM2 karma

"Fixing Earth" so to speak is very complicated and there are so many different opinions on what that would actually entail. So for this project we decided to try something new and exciting, instead of something that can honestly be a bit dispiriting to think about

jmb3261 karma

How do you interrupt the cellular mitosis?

Serious: are you looking for help or are there ways for others to be involved?

ExeterUniIGEM2 karma

In terms of the E.coli we are genetically modifying? It’s not necessary for us to interrupt this as we want it to replicate with all the new DNA we have transformed them with! :)

It might be a little late! Our team were assembled in February of this year and have been working full time since June on this project. We had to go through interviews and applications to get involved and there were certain criteria (including being a University of Exeter student). Regardless, there’s less than a month to go so we have done most of the work needed for the iGEM Jamboree in October.

If you are a student, there are over 300 teams from around the world participating in iGEM so ask your university or high school to be involved next year! Some will start recruiting as soon as the Jamboree is over so best to look soon. Also, if they are involved this year, it’s a good idea to look up and support this years team. It’s such an exciting point for all the projects and you’ll get to see most of them fully formed. Head to http://2018.igem.org/Teams to see who’s participating this year and to have a look at their Wikis. Good luck!

jwirth051 karma

Are any of you gentlemen also joining the search for FaIrY G0D PaReNTS!?

Link: https://wildhunt.org/2018/08/university-of-exeter-looks-at-the-best-way-to-summon-fairies.html

ExeterUniIGEM2 karma

Hadn't heard about that! Sounds really interesting and goes to show how research can be done into almost any field.

I don't have any current plans to join the field of History of Magic though ;)

hydroflame44181 karma


ExeterUniIGEM3 karma

Why produce a bioreactor to produce oxygen on Mars, or specifically why are WE doing this?

hydroflame44181 karma

Why produce oxygen on Mars?

I could go on about mars but really my question is. Why not do something for earth instead? It's much easier to make earth more habitable than to make mars habitable.

Is the goal to make all mars air breathable (I don't even want to calculate the volume of air that would be) or just have a machine to make small scale environment breathable. What about the co2 in the atmosphere. I'm sure you already know, but for other reader. The reason you feel the need to exhale is because your lungs fill with CO2, which gets detected and signals your body to exhale. With 95% CO2 on mars (as opposed to ~20% when you hold your breath) that feeling will be permanent unless something is done.

ExeterUniIGEM2 karma

I see!
The goal is not to make all Mars air breathable, it's to produce oxygen for human consumption, so in a closed environment. The amount of oxygen we would have to produce to terraform Mars would be astounding and we can't be sure that it wouldn't be stripped down in the same way the atmosphere has before.

It is probably easier to make Earth more habitable, as you said, but it's also very exciting to think about the prospect of exploring the universe. To do this we would most likely start within our own solar system.

So our project might not be the one solving the most pressing isues of humanity, but it would be really cool to contribute to humans exploring more of the world.

AMAInterrogator1 karma

Wait? So, the first plan for Mars is to contaminate it?

Would a chemical reactor make more sense, from a biological scientific perspective, until some reasonable evidence has been established that it isn't a terrible idea?

ExeterUniIGEM2 karma

I wouldn't say it's the first plan. Our project is just looking into something that might be useful far into the future.
Reducing perchlorate chemically is an explosive reaction, which would be somewhat unfortunate for a vulnerable martian colony. And it's good to have multiple different methods of producing oxygen that can then be compared.

Is there currently evidence that this is a terrible idea? More seriously though: this would never be approved to go to Mars without very serious scientific checks. This is something we have considered.

We have thought about this being used to produce oxygen for a biodome, so not releasing oxygen into the atmosphere. Our bioreactor also has containment procedures built in, that we hope would kill the bacteria if necessary. Copper beads could be passed through to kill the bacteria. They are also not resistant to UV radiation so if bacteria managed to get outside the bioreactor they should die pretty quickly.

But again, it is a big risk, but we believe that this would be a risk no matter what a Mars colony would look like.

Telenerd0 karma

Wouldn't this contaminate mars with possible unknown side effects?

ExeterUniIGEM3 karma

It could definitely have currently unknown side effects. There are no plans to actually put this on Mars yet as it would be necessary to a thorough risk analysis. There is always going to be risk of contamination if humans decided to colonize Mars and that is of course something to keep in mind when making that decision.

tomashcu0 karma

If you can turn soil into oxygen surely we could convert waste into chemical energy?

ExeterUniIGEM3 karma

We wish! We are using a process that converts the chemical perchlorate found in Martian soil into oxygen. It's not the soil as a whole that is being turned into oxygen. Waste into chemical energy is great dream though.