Describe how and why you chose your iGEM project.
Demystifying our project. From core principle, to challenges, breakthroughs and innovation. A journey shaped by curiosity, persistence, and an unfathomable hunger for innovation and impact. Discover how we have turned our bold idea into a tangible solution one step at a time/one research paper, one experiment, and one insight at a time.
From the first moment humanity gazed at the stars, we have been driven to uncover their secrets and explore the cosmos. After centuries of mapping our world, the past century has seen us begin our journey beyond Earth, facing our greatest challenge yet. Space is our final frontier, calling us to push the limits of knowledge, technology, and survival.
By no means, however, is this an easy task. Space is vast, unforgiving, and far from hospitable. Beyond Earth, there is no atmosphere, intense radiation, extreme temperatures, and immense distances between even our closest neighbors. Achieving space travel requires solving countless problems to create an environment where astronauts can survive and thrive. One of the most critical challenges is nutrition. Without reliable access to balanced diets, astronauts risk losing strength and health over time. Ensuring a steady supply of protein, the key macronutrient for maintaining muscle, bone, and overall performance, is particularly vital. Our team focuses on this problem: safeguarding astronaut nutrition by addressing the protein gap in space.
Microgravity profoundly affects the human body. Without Earth’s gravity, astronauts lose muscle volume and strength, with mass reportedly decreasing by 20% after two weeks and up to 30% on longer missions [1]. Exercise can mitigate some losses, but protein synthesis slows while protein degradation increases [2]. This imbalance drives atrophy and weakness, threatening health and performance during long missions. A reliable, efficient source of protein is therefore essential, not just to meet dietary needs, but to counter the biological shifts microgravity induces.
Currently, most missions remain in Earth orbit, with the ISS serving as the hub for multi-month stays. Astronauts depend on regular resupply from Earth, but these missions are costly, complex, and risky, transporting even 1 kg costs agencies like NASA around 23,400 dollars [3]. While manageable in orbit, resupply is impossible for long or distant missions, making a closed-loop nutrition system vital, especially to maintain a steady supply of protein, a nutrient too important to stockpile.
A bioregenerative life support system provides a sustainable way to produce nutrients and recycle waste during long-duration space missions. Using genetically modified microbial cultures, a BLSS can convert organic and nitrogenous waste into high-protein biomass, giving astronauts a reliable source of this critical macronutrient. Beyond protein, similar systems can be used to regenerate water, oxygen, and other essential resources, reducing dependence on costly and risky resupply missions, lowering launch mass, and improving overall mission sustainability. For long-term missions, a BLSS ensures astronauts receive sufficient calories and balanced nutrients to counteract the negative effects of microgravity, such as muscle atrophy, bone loss, and immune system changes, making it essential for health and performance on extended journeys.
One particularly promising approach within biomanufacturing is the use of single-cell proteins (SCPs), which are microbial biomass sources rich in protein and other essential nutrients. SCPs can be produced from waste streams, such as astronaut urine or urea, converting what would otherwise be discarded into high-value nutrition. Beyond protein, these cultures can provide vitamins, amino acids, and other micronutrients, making them a versatile and efficient solution for space missions. Their adaptability and ability to grow on minimal resources make SCPs a compelling component of future bioregenerative life support systems, demonstrating the viability of producing essential nutrients on board using waste as a feedstock.
Our goal is to develop a bioregenerative system that can transform astronaut waste into a sustainable, high-value protein source for long-duration space missions. To achieve this, we plan to genetically engineer the metabolic pathways of Saccharomyces cerevisiae , a well-characterized yeast species, to enhance its ability to utilize urea, commonly found in urine and other nitrogenous waste, as a nitrogen source. Concurrently, we aim to upregulate the yeast’s amino acid biosynthesis pathways, with a focus on glutamate and glutamine, which are key contributors to cellular protein content, thereby increasing the overall protein yield per cell.
These modifications allow the yeast to efficiently convert urea extracted from astronaut waste into Single-Cell Protein (SCP), which can be harvested, processed, and incorporated into the crew’s diet as a nutritionally rich, renewable protein source. By integrating this system into spacecraft life support, we can significantly reduce reliance on pre-packaged food supplies, minimize waste accumulation, and close the nutrient loop within a closed ecological system.
The modified yeast cells can be cultured within a bioreactor, which would take urea separated by already existing urine processing systems within space crafts [4] as the inlet feed and convert it into SCPs within the yeast cells, the culture can then be harvested and processed into a powder, which can directly be used as a rich protein source.
One of the main hurdles that implementing a system like this in outer space is the presence of a wide spectrum of harmful high energy radiation, which, with no atmosphere to mitigate them, pose a major threat to the survivability and viability of our biomanufacturing microbes.
Space radiation, particularly UV and ionizing radiation, has profound effects on eukaryotic cells. UV-C exposure at 254 nm can generate up to 10,000 DNA lesions per cell per joule per square meter. Cells irradiated with 30 J/m² UV-C have been estimated to accumulate approximately 1,200 lesions per chromosome, equivalent to roughly one lesion every 8 kb per single strand, resulting in extensive genomic damage that can overwhelm cellular repair systems and threaten cell survival [5].
Experiments on Saccharomyces cerevisiae show survival rates drop by over 90% at UV doses of 100-150 J/m² [6]. Exposure to ionizing radiation produces an LD₅₀ around 200-300 Gy . Such exposure can elevate mutation frequencies by up to 100-fold and increase DNA damage aberrations by an order of magnitude when cells are subjected to heavy ions, such as those found in galactic cosmic rays [7].
Some of these effects are mitigated by shielding built into the spacecrafts themselves, especially when considering UV radiation, however high energy ionising radiation like galactic cosmic rays would still prove a problem. When going about establishing a hypothetical off-world colony even UV radiation becomes a problem, as traditional UV-resistant materials could add a large amount of weight to the payload.
In order to increase the survivability of our biomanufacturing cells, we plan to create genetically modified radiation resistant yeast, utilising a damage suppressing gene known as DSUP which is found within tardigrades, an organism famous for its exceptional survivability in very harsh conditions, even managing to survive for extended periods of time in the cold vacuum of outer space [8]!
This gene is responsible for a wide variety of protective functions within tardigrades, including dehydration tolerance, protection against oxidative stress and most relevant to our purposes, DNA Protection from radiation damage. It forms a sort of “molecular shield” around DNA, reducing the amount of double-strand breaks (DSBs) caused by ionizing radiation (like X-rays, gamma rays). Studies have also demonstrated that the expression of DSUP within other organisms has successfully decreased the amount of DSBs occurring on exposure [9].
This would increase the survivability of our yeast cells against radiation exposure significantly, making them far more viable for applications in long term outer space missions and for use in future off-world colonies.
UV radiation mainly causes chemical changes to DNA bases, like abnormal bonds between neighboring bases, rather than breaking the DNA strands [10]. This is different from the strand breaks caused by ionizing radiation. Since DSUP mainly protects against strand breaks, it is not very effective against UV damage, therefore, our organisms would greatly benefit with an extra protection mechanism that would protect them against UV radiation specifically.
By a stroke of luck, a serendipitous discovery was made in our lab. During an unrelated study of the nutritional requirements of different amino acids of P. vulgaris. A culture containing L-tyrosine that was left behind, produced a peculiar brownish hue. Upon later observation it was determined that the brownish substance was in fact eumelanin, which was synthesised by the organism, further investigation also allowed us to separate this eumelanin in a dry powder form.
To capitalise on this finding, we integrated this eumelanin production pathway into our design for radiation protection, leveraging the well-established UV-shielding properties of eumelanin to enhance the resilience of our chassis against space radiation. We created films using a PVA solution where our produced melanin was uniformly distributed throughout the sheet. These melanin infused PVA films can be utilised as lightweight external coatings for the bioreactor within which our BLSS would be sustained, serving as an effective shielding against the effects of UV radiation
Collectively, these innovations form a sustainable, radiation-tolerant, and resource-efficient protein production system, capable of reducing payload mass, minimizing waste, and closing the nutrient loop for long-term extraterrestrial missions.
The successful implementation of our system would represent a major step toward self-sufficient life support in space, enabling humanity to sustain long-duration missions to the Moon, Mars, and beyond.