U of C iGEM Team

Case Study: University of Calgary 2017 iGEM Team

The team started their journey excited about space exploration and space agencies’ plans to send people to Mars. As they learned more about this, they became aware of two problems related to long-term space missions: What will happen to all the human waste produced during missions? How will people get the supplies and materials they’ll need in space? To address these problems, the team designed a process for turning human waste into usable products. They used synthetic biology to create bacteria which can convert solid human waste into bioplastic and also export it outside the cells for easy harvesting. The plastic produced could then be used directly on the spaceship to 3D print various items needed during the mission.

Team wiki page: http://2017.igem.org/Team:Calgary

Charting the Team’s Design Thinking Process

Empathize

Who have you spoken to?

• City of Calgary wastewater management services
• Advancing Canadian Wastewater Assets research group at University of Calgary
• Biochemistry and synthetic biology professors
• Astronauts Robert Thirsk and Chris Hadfield
• Made in Space: 3D printing company with instruments currently aboard ISS (International Space Station)

What are the most impactful common issues they experience?

Astronauts are challenged by the disposal of human waste, as it is generally shipped back to Earth (with high fuel costs). They also must meet the challenges of anticipating everything they may need on a space mission.

Local wastewater management experiences the most issues with cleaning residual contaminants, like antibiotics for example.

What have they already tried to solve their problem?

Astronauts presently have the option to package and eject their waste into space, but this creates space debris, which can be fatal if it later comes into contact with a spacecraft. They can currently recycle urine to water, but nothing yet exists for solid waste. The ISS is equipped with a 3D printer to make tools as needed, but the starting materials are used sparingly and its supply needs to be replenished.

Define

Who is your primary audience?

After the iGEM competition, we are in touch with astronauts and space agencies like the National Aeronautics and Space Administration (NASA) and the Canadian Space Agency (CSA).

What is the challenge you are trying to solve?

We are trying to solve two problems: 1) how to manage solid human waste on long-term space missions to Mars and 2) how to produce a renewable building material that can be easily customized to unanticipated and specific needs.

What is the outcome you want for your users?

First and foremost, we want our system to be safe to use, so that no astronaut’s health is compromised. We also want it to be fully contained to reduce the risk of intergalactic contamination. It must be easy to use, so that it doesn’t require constant monitoring, and would ideally have low energy requirements to run.

Ideate

What solutions already exist?

Currently, astronauts can 3D print tools as needed aboard the International Space Station, but no solutions exist to recycle waste and turn it into a useful product.

What are some radical new solutions you can think of?

Our idea is to use genetically-engineered E. coli cells to digest human waste and produce PolyHydroxyButyrate (PHB), a biopolymer that can be used to 3D print tools – we call our product Astroplastic.

We will use two bioreactors. The first will contain human waste and naturally-occurring gut flora which will ferment the waste to produce volatile fatty acids (VFAs). These VFAs will be used in the second bioreactor as a food source for our engineered E. coli in the production of PHB. The PHB will be separated from the bioreactor by filtration and dissolved air flotation to produce a powder that can be used in 3D printing.

What other industries/ideas have you used as inspiration?

Industry currently employs engineered PHB-producing bacteria to make bioplastic from agricultural waste, which is high in cellulose and an effective bacterial food source. Since human waste is also composed primarily of cellulose, we used this idea for our project. We were also inspired by Space X, not by any particular design, but by their efficient approach to and designs for the race to Mars. To be competitive, we must offer the same efficiency in our product design, we thought.

What are your constraints?

Safety is our number one priority, so our product must contain all contaminants and either filter or sterilize the end products before they are extracted from our system. During our research, we avoided working with real human waste in the lab, to reduce our health risks. We also needed to be aware of the energy constraints. To ensure our project fell within reasonable energy demands, we used NASA’s Equivalent System Mass (ESM) guidelines. The ESM guidelines are used by NASA to convert parameters like power requirements, volume, and crew time commitment to one single unit of mass (Kg).

Prototype

What are core assumptions/parts of your MVP (minimum viable product)?

Our MVP requires an input food source, naturally-occurring bacteria, and our engineered E. coli. We assume that our final system’s design will be safe and contained, and that all parts will function under Mars’ gravity. While our final design uses a more sophisticated and energy-efficient plastic extraction method (dissolved air flotation), we are currently using a more basic, bleach-based method to extract the plastic in the lab.

How will you test your MVP quickly?

To avoid health risks from using real human waste and natural gut flora in the lab, we used a safer NASA recipe for solid waste, which included yeast to produce VFAs instead of the bacteria in the human gut. This allowed us to bypass applications for a higher biosafety level lab, and ethic approval for using human material.

Instead of cloning our 7 required genes from each source individually, we were able to have them synthesized for us by Integrated DNA Technologies, saving months of work.

We also divided labour into specialized subgroups so we could work on multiple aspects of the project simultaneously. Lastly, we asked for assistance from other laboratories around the university who offered more specialized equipment when analyzing our work, instead of having to raise funds to purchase the equipment ourselves.

Who can you get to test it?

We tested the engineered bacteria and their ability to produce PHB from VFAs ourselves at the U of C iGEM lab. Once enough product is made, we plan to employ the University’s 3D printers to determine the suitability of our plastic for 3D printing.

Test

How do users respond to your solution?

The astronauts we contacted were optimistic about Astroplastic, and shared that 3D printing tools and materials will be a necessary component of long-term space travel. Robert Thirsk stressed the importance of safety aboard spacecraft, and that we will need to ensure our PHB-producing system is entirely contained and sterile for end users. The company Made in Space, while not an end-user of our design, also responded well to our idea to use Astroplastic for SLS (Selective Laser Sintering) 3D printing, since that method for 3D printing isn’t currently used in space.

What are the strengths of your solution?

Our Astroplastic solution solves two problems at once: how to manage waste in outer space and how to continuously produce a useful building material. Currently these two problems have not been solved for long-term space travel. Astroplastic fits the ESM guidelines for a feasible tool to employ on long-term space missions and uses a minimal amount of energy. Furthermore, by-products of our bioplastic pipeline include water and char. Water is clearly a necessary resource critical for survival, while char can be used as a building material, for radiation shielding, and as a food substrate as required.

What are the weaknesses of your solution?

Our system has many working parts, and each of them present an opportunity for something to go awry. We have yet to determine a feasible design that contains the bacteria to mitigate health risks to astronauts. We also need to look into better ways to close the carbon cycle for astronauts on long-term space missions so they are not required to bring additional material. Currently, carbon in the form of human waste is used to make biodegradable PHB, but how easily does PHB degrade, and can it be used as a fertilizer to close the carbon cycle? These are questions we still need to answer.

What will you try next?

Since safety is a major concern, it will be our main focus next. While we can always use physically protective barriers and equipment to reduce risk of contamination, we are also considering to engineer our bacteria to essentially commit suicide should they escape their confinement. We have also been given the opportunity to test specific parts of our product in zero gravity with the Canadian Reduced Gravity Experiment (CAN-RGX) Design Challenge in association with Students for the Exploration and Development of Space of Canada (SEDS-Canada) and the Canadian Space Agency (CSA).