Our current research “MicroPET I” utilizes Pseudomonas putida, a microorganism strain with a capability for breaking down polyethylene terephthalate (PET) and upcyclingcling it into β-ketoadipic acid (BKA), a performance-advantaged bio product that can be polymerized into Nyon. We have developed the first version of a compact, modularized bioreactor that allows us to automatically run biological experiments, allowing us to scale and monitor the experiment with precision. However, we are only able to set up two replicates in this current experiment and study the single strain: Pseudomonas putida KT2440. Our current payload can be used as the foundation for this new mission. Our interdisciplinary team has previously launched multiple payloads in ISS with the knowledge and experience to execute the mission.
The payload aims to study the growth, behavior, and efficiency of a consortium of bacteria and enzymes that degrade plastics. The payload is an automatic culture system that contains biological materials, growth medium, buffer, preservatives, and PET pieces. Based on our prior work using Pseudomonas Putida, we would identify other species of microbes through literature review and environmental screening to create different consortium combinations and test them out in laboratory settings, and select the promising consortiums for in-orbit experiments. Once in-orbit, the system automatically activates and proceeds with the pre-programmed experiment schedule in which we limit carbon source in the growth medium, providing selective pressure for evolution towards activity and growth of the microbe consortium that degrades PET more efficiently.
We have developed an automatic culturing bioreactor that will work with in-orbit facilities such as Nanorack’s BlackBox and Nanolab (multiple-U). The optimal mission duration would be 4-8 weeks in orbit with power supply and data downlinking capacity. Late-load (L-1day to L-5 days) would be optimal if cold stow is not available pre-launch. Our current payload can be used as the foundation for this new mission. After the experiment, we plan to measure the biodegradation using both physical measurement (weight loss, 3D scan of the PET inserts), and chemical analysis (spectrometry analysis of the byproduct and the upcycling yield). We will also perform quantitative genomic, metabolic, and proteomic analyses to understand microbial adaptation and biodegradation pathways. We will also utilize an available high-quality validated genome-scale model of strain KT2440 (iJN1462) to interpret degradation results; a similar approach could be used in the longer term to analyze productive communities.