That is how long a single plastic bottle thrown into the sea today will pollute the environment. The pollution by plastic will cause catastrophic effects on the environment for up to 500 years and will be a major ecological problem for coming generations.
400.000.000 MT OF CO2
are produced by burning plastic every year. Less than 30% of the plastic in the EU is recycled. Besides that, recycling is a downcycling process whereby the quality of the plastic is sequentially decreasing, which is why a second recycling process is often not possible.
We are decomposing PET into its monomers terephthalic acid and ethylene glycol by transferring the genes for the enzymes PETase and MHETase into the genome of green alga Chlamydomonas reinhardtii. The alga will be grown in a bioreactor, enabling simple harvesting of the degradation products. This system, powered by nothing but light and CO2 allows for a cheap, efficient and eco-friendly method of recycling our PET plastic waste.
Our model visualizes the attachment of the PETase to its substrate and the influence of the R280A mutation. Also we could identify a possible glycosylation site close to the active site. This molecular modeling simulation taught us a lot about the PET cleavage by PETase and heavily impacted our project design.
We created the "Kaiser Collection", a novel golden-gate based toolbox containing 20 parts specially designed for working with Chlamydomonas reinhardtii. This is a selection of the most useful constructs, while we have created and tested many more.
While creating, using, and testing our 77 constructs we were not just looking to realize our vision. All this went along with optimizing our system and parts for more effective results. Over time, our results got faster and less ambiguous.
Chlamydomonas reinhardtii is a eukaryotic organism that grows in freshwater requiring only light and CO2. It is the perfect organism for a constant enzyme production. Chlamydomonas even attaches to plastic surfaces which increases the enzyme concentration at their target location. Working with this organism we designed the Kaiser Collection and additionally created the “Chlamy Guide” in collaboration with iGEM team Sorbonne.
The big advantage of an enzymatic recycling system is that PET will be decomposed into its monomers. The purified TPA allows the resynthesis of high-quality PET while protecting valuable resources. EG is high in energy and can be turned into ethanol for biofuel or can be used as a source of carbon to support the growth of other microorganisms.