Describe how and why you chose your iGEM project.
Davy Hsu approached Nico Chung with a problem: Davy wanted astronauts to be able to recycle PET garbage into high-quality semi-crystalline PET filament for 3D printing. Nico suggested that AEI students were capable of genetically engineering e. coli to produce the necessary proteins to depolymerize PET. The challenges included operating at reasonably low temperatures and producing PET filament with adequate crystallinity.
The section below is a separate, independently-written draft of the project description, produced by a team member outside the main documentation process. It is kept here for reference and comparison and has not yet been fact-checked by team leadership — treat specific claims accordingly. It may be removed or revised once reviewed.
The complete scientific description covers the chassis, the pathway, the enzyme, the containment, and the reason any of it ends up off-planet.
Polyethylene terephthalate is the most-produced single polymer in the consumer world. It is also one of the most stubborn: PET does not meaningfully biodegrade on human timescales, accumulating in oceans, soils, and on long-duration spacecraft, where it arrives as packaging and never leaves. On a six-month Mars-class transit, every wrapper, drink pouch, and food tray that crosses the cargo airlock occupies mass, volume, and crew attention for the rest of the mission. The framing used here: PET is not waste, it is a poorly-formatted feedstock.
Built on the 2016 discovery of Ideonella sakaiensis 201-F6, isolated from a Japanese bottle-recycling site (Yoshida et al., Science, 2016), which expresses two enzymes that together dismantle PET into something a normal heterotroph can metabolise:
Both enzymes share the canonical serine-hydrolase catalytic triad: Ser–His–Asp.
Argues for E. coli K-12 over BL21, W3110, or Pseudomonas putida — not for expression strength, but because K-12 has been characterised continuously since 1922, giving it the best-documented dormant-state survival and the simplest regulatory dossier of any candidate chassis.
Screens three anchor systems — Lpp-OmpA, Ag43, and INPNC — for which one best presents PETase outwardly without compromising membrane integrity.
Two modules scoped but not committed: CO₂ fixation (partial CBB-cycle augmentation to fix cabin CO₂), and nutrient recovery (feeding TPA + EG into amino-acid biosynthesis, closing a loop from PET → monomer → biomass → crew nutrition).
Hard rule: nothing leaves the bioreactor cartridge alive. Two orthogonal kill switches in series; both must remain off for the cell to survive.
Explicitly not positioned as competing with industrial enzymatic recycling, which already exists and scales at megatonne capacity. The narrower claim: a microbe with the right enzyme, in a small cartridge drawing crew-cabin CO₂ and emitting crew-relevant carbon, is suited to closed-loop life support — a different kind of problem than terrestrial-scale plastic processing.