Hardware in iGEM should make synthetic biology based on standard parts easier, faster, better, or more accessible to our community.
Showcasing the hardware components that our project has brought to life. Documenting the first screw turned to the last bolt tightened, this page is a testament to our engineering ethos, creating solutions with tangible, real-world outcomes.
Selecting the optimal reactor for our project was a pivotal decision. To host efficient cell agitation and to ensure adaptability in the demanding space environment, we designed an external loop airlift bioreactor, taking into account the challenging parameters of microgravity and radiation. The design leverages peristaltic pumps and temperature sensors to ensure effective control and operation in extraterrestrial environments. Looking ahead, the design offers potential for further refinement, paving the way for an easy, efficient, and robust system in space.
Our team, through research and investigation, has created a design that suits our requirements for a bioreactor. We read about various types of bioreactors and concluded that an airlift bioreactor is the best choice for helping us achieve our desired output. We needed a design that could keep the cells of the culture constantly agitated, even in the absence of space. Most bioreactors utilise gravity as an essential element of their operation.
In microgravity environments, buoyant forces are negligible, making it difficult to sustain natural convection currents. On Earth, convection arises from temperature-induced density differences, where warmer, less dense fluid rises and cooler, denser fluid sinks—driven by gravity. In space, alternative mechanisms, such as forced flow, must be employed to achieve fluid mixing and heat transfer. Additionally, the cells in the culture are delicate and require low shear stress, as well as gentle pneumatic mixing; thus, choosing an airlift bioreactor is more favourable.
Based on insights from Dr. Naik, we were advised to assess the biocompatibility and spaceworthiness of our chosen bioreactor materials, especially in terms of withstanding the harsh conditions during launch and docking.
During a meeting with the Axiom team, we learned that urea separation from astronaut waste is already managed, allowing us to eliminate the biocide addition step in our system. This helped streamline the design of the nutritional medium.
From our discussion with Mr. Pariccha, we learned that vacuum conditions are not a concern, as the ISS maintains a constant temperature and pressure.
Thus, through careful consideration and building upon the feedback from experts, we concluded the following parameters for our bioreactor prototype.
We also concluded that our system would benefit from the following:
Additional feedback emphasized the need to:
Circuit:
Before operating the reactor, the vessel and loops are sterilized, and the medium is added. We then sparge air into the riser leg at a low rate, creating a density difference that drives upward flow in the riser and a return downward flow through a separate downcomer leg, connected externally at the top and bottom, establishing a continuous loop without mechanical impellers. The bubbles flow to the top and disengage at the top separator,after which the degassed liquid descends through the external loop downcomer, closing the circuit.
Direction of flow:
Upward in the riser with gas–liquid two-phase flow; this is the main mass-transfer zone with higher gas holdup and mixing intensity.
Horizontal top connection to a disengagement section where gas exits to headspace/exhaust; liquid turns into the downcomer mostly bubble-free.
Downward in the external downcomer as single-phase liquid, the bottom connection returns liquid to the riser inlet region to be re-entrained by new bubbles.
Utilizing mathematically optimized CAD drawings and high-efficiency 3D printers, we successfully fabricated a functional prototype of our bioreactor using Polylactic Acid (PLA)—a biodegradable thermoplastic known for its strength and sustainability. The structure was sturdy, compact, lightweight, and strong. Due to time and resource constraints, we were unable to build a melanin PVA coating over our bioreactor. It resembled the miniature version of the actual bioreactor, which we aim to build in the future.
We conducted a preliminary test of our bioreactor prototype, pumping water through its system using peristaltic pumps. We used water as our test fluid in place of live cultures to simulate early-stage operation. The flow rate was carefully calibrated to match that of a standard aquarium setup, ensuring gentle yet consistent circulation. Over the course of one hour, we observed the reactor’s behavior under sustained conditions of temperature and pressure, focusing on fluid dynamics, leak resistance, and structural stability. Though simple in setup, this test offered meaningful insights into the system’s readiness for biological operations, laying the groundwork for future process modeling. It marked a significant step forward in validating the functionality and resilience of our design.
After an hour of operation, a noticeable leak emerged from the flange connections, compromising the system’s ability to hold water securely. To prioritize safety and prevent any potential damage to our prototype reactor, we promptly halted the operation and followed our safety protocols with diligence. This swift response ensured that the issue was contained, no further harm occurred, and the integrity of our workspace and equipment remained intact.
Our prototype allowed us to explore various aspects of bioreactor design, structure, and operations. Despite our careful planning and meticulous design, our design failed to operate at its highest potential. Water, the working fluid, began to leak through the flanges, forcing us to halt the operations. Due to resource constraints, we were unable to fully investigate how the system would behave under microgravity conditions. Similarly, ensuring complete leak-proofing, selecting materials capable of withstanding extreme temperature and pressure variations, and validating the structural binding under dynamic stress were challenges we could not address in this phase. We believe that it's due to these gaps in practical knowledge that have culminated in the failure of our prototype. These limitations, however, have helped us identify critical areas for future exploration.
Design Features and Materials
Learning from our previous mistakes, we have actively sought ways to make our bio-reactor sturdier and leak-proof. Before we scale it up to an actual bio-reactor capable of functioning efficiently in a space environment, we need a prototype that works like a charm in normal surface conditions.
We have revised the design to ensure that the stress that can lead to mechanical damage is minimized. We shall be using caulk to seal connections between flanges and use precision O-rings to ensure watertight connections.
To protect the internal contents of the bioreactor from harmful space radiation, we plan to coat the reactor with a melanin-polyvinyl alcohol (PVA) coating. Caulk has been used to seal connections between flanges, ensuring leak prevention and maintaining the integrity of the reactor system. We also plan to simulate pressure and stress conditions to model how the reactor behaves under varying temperatures and pressures. With this revised model, we will consult our experts and mentors, ensuring that no stone is left unturned.
Microgravity and Space Environment Considerations
A better understanding of microgravity, vacuum, and the nature of space missions was crucial for our project. The functions of microorganisms—critical for SCP (single-cell protein) production—are extensively impacted under these conditions. This required significant adaptation in both reactor design and microbial choice.
Bioreactor Research and Design Evolution
We began by researching various bioreactor types, comparing:
This process led to a redesign focused on urea consumption mechanisms and the production of palatable single-celled proteins (SCP). Our team also aimed to establish quantitative benchmarks, including protein yield metrics, to assess system performance.
Radiation Protection and Nutritional Design
Following expert advice, we focused on optimizing melanin concentration to enhance radiation shielding. The palatability of the derived protein became a key design goal, as the end product needs to be both safe and consumable. The removal of the biocide step, thanks to Axiom’s insights on waste treatment, allowed us to simplify and refine the design of the nutritional medium.
Technical and System-Level Challenges
Designing a closed-loop bioreactor system presented several technical challenges, including:
We also had to assess the economic feasibility of the system, considering both space mission constraints and potential applications on Earth.
Modeling and Simulation Enhancements
To support technical development, we are enhancing our dry lab modeling using open NASA datasets. These simulations help us:
This modeling phase plays a crucial role in determining the feasibility and performance of the bioreactor system under realistic mission parameters.
Every prototype has a story to tell. This story is not just of success but also of resilience, persistence, and dedication, even in the face of setbacks. iGEM-ICT continues to work on developing a bioreactor that will soon change the way proteins are manufactured and consumed, not just in space stations but also here on Earth. Our team is working behind the scenes even as you read this wiki page.
As a part of the legacy that we create, a few foundational points that every iGEM team must know about that would venture into this daunting task of building a bio reactor -