iGEM Aachen 2019: Plastractor

by Alina Egger and Yasmin Kuhn

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Currently everybody talks about environmental pollution by plastic. But not only big plastic waste, like plastic bottles, are a problem for us, but also microplastic, which e.g. was found in drinking water. Microplastics, particles smaller than 5mm, generated by degradation via wave motion and UV radiation, can work their way into the marine food chain and eventually into the human body.

With our project, we want to approach the microplastic problem. On the one hand we want to produce an easy way to detect micro- and nanoplastics in fluids and differ between different polymers. On the other hand, our project should create an easy way to extract them. Magnetic purification seemed to fit, as it doesn’t require any chemicals or elevated equipment.

Currently there are known magnetic bacteria existing, e.g. Magnetpospirillum gryphiswaldense, which thrive in the sediments of freshwater streams or marine sediments in very low oxygen environments. The most fascinating ability of these bacteria is their capability to produce so called magnetosomes, spherical vesicle-like structures of membrane-coated, biomineralized ferrite monocrystals with an approximate diameter of 45 nm. These are aligned by special cytoskeletal proteins inside the cell body to form little compass needles, which allow the bacteria to orient themselves along the earth’s magnetic field.

We want to develop novel fusion proteins embedded into the vesicular membrane of magnetosomes being able to specifically bind certain polymers, for example polypropylene (PP). They are consisting of a transmembrane domain as well as a variable linker domain and a domain for binding the polymer.

Figure 1: Schematic binding of polypropylene (PP) to the magnetosome mebrane (right) via the constructed fusion protein (left).

Figure 1: Schematic binding of polypropylene (PP) to the magnetosome mebrane (right) via the constructed fusion protein (left).

Figure 2: Fluorescent detection of the bound plastic particle with bound fluorescent markers.

Figure 2: Fluorescent detection of the bound plastic particle with bound fluorescent markers.

Novel fusion proteins embedded into the vesicular membrane of magnetosomes can be developed, able to specifically bind certain polymers, for example polypropylene (PP). For detection purposes there is a fluorescent protein marker inside the fusion protein that marks the polymer particle for fluorescent detection.

Our project aims to make the world a little less “plastic”. We don’t want to build up new plastic but to remove the one already present. Join the fight against microplastic and support us by visiting our website. You can ask us anything via e-mail (igem@rwth-aachen.de) and also follow us on Facebook, Instagram and Twitter to stay in touch with us and our journey to the competition in October.

The 2019 Aachen iGEM team

The 2019 Aachen iGEM team