MicroPET: Investigation of Biodegradation of PET Plastics in Spaceflight

Although biological cultivation in space has enormous potential to enable in-situ resource utilization in space, current space flight infrastructure for growing microbes without resource-intensive astronaut support is lacking. Here, we present an autonomous payload for enzymatic reactions and microbial cultivation with fully programmable serial passaging and sample preservation. The payload is a compact, modular bioreactor system that allows for automatic media transfers and precise data monitoring from integrated sensors (e.g., temperature, optical density, etc.). 

We apply this system to study the biological upcycling of the commonly used polymer polyethylene terephthalate (PET) in space in a two-step system in which PET film is enzymatically degraded and microbially upcycled. First, PET is depolymerized by the enzyme PETase, and second, the released monomers are pumped to a microbial chamber where an engineered bacterium converts the monomers to a higher-value product, namely beta-ketoadipic acid (BKA). BKA can be polymerized into a polyamide (nylon) material with improved properties over nylon-6,6 — a versatile polymer used in the production of textiles and molded parts including air intake manifolds, electro-insulation elements, and hinges. This platform also enables serial sample collection and storage for terrestrial analysis including RNA and DNA sequencing as well as proteomics. We posit our open-source system will enable increased access to synthetic biology experiments and applications in spaceflight that will ultimately enable resource-sustainability in space travel.

This new environmental research initiative is a collaboration between MIT Media Lab Space Exploration Initiative, the National Renewable Energy Laboratory (NREL), Weill Cornell Medicine, Harvard Medical School, and Seed Health.