Making biodegradable plastics from syngas: a biotech solution to waste and plastic pollution
Syngas is a mixture of CO, H2 and CO2 that can be produced from the gasification of renewable feedstocks, such as biomass, organic waste, or industrial residues. Chemical conversion of bio-based syngas is challenging due to the presence of impurities like sulfur compounds. However, biological conversion is well-suited to bio-based syngas, because some microbes can tolerate well – and sometimes even benefit from – these impurities. A novel fermentation process was developed to produce biodegradable polyester plastics using syngas (or other CO-rich streams) as a feedstock.
Microbial conversion of CO-rich gases is already applied at scale, typically using pure cultures of acetogens (e.g. Clostridium autoethanogenum), to produce simple molecules like ethanol and acetate. Our innovation lies in the use of microbial mixed cultures to establish a microbial food-web, enabling the production of more complex molecules. A simplified example is given in the figure below. Microbe A can produce polyhydroxyalkanoates (PHA), a biodegradable plastic. It uses CO for energy, releasing H2 and CO2 as by-products. Microbe B then converts these gases into acetate – an essential carbon source for Microbe A to produce PHA. Together, the two microbes transform CO into bioplastic in a single, integrated fermentation process.
What makes our system unique?
- Bioplastic production from CO-rich syngas, compatible with syngas derived from renewable or waste feedstocks
- Production of C4-C5 PHA blends for customisable material properties
- Integrated defined co-culture or (enriched) mixed culture in a single reactor, simplifying operation and increasing efficiency
- No need for added sugars or organic acids – PHA is produced directly from the gaseous substrates alone
- Patented technology
High-potential applications
- Valorisation of syngas generated from renewable feedstocks (biomass, wastes), with minimal gas purification required
- Carbon capture and conversion via microbial fermentation
- Sustainable PHA production, including C4-C5 PHA blends
- Carbon-neutral or carbon-negative bioplastic manufacturing
Development stage & collaboration opportunities
The technology is at TRL 4 and protected by IP. Several commercial parties have shown interest. Wageningen University & Research offers technical expertise to support further development and application.
Contact
Interested? Get in touch with:
dr. N (Nikita) Sajeev
Medewerker kennisvalorisatie
Publications & Patents
- Machado De Sousa, D., Ruano, T. M. T., & Diender, M. (2024). Process for the production of polyhydroxyalkanoate. (Patent No. WO2024236121).
- Torres Ruano T.M. Diender M., Sousa D.Z. (2025) Microbial synergy between Rhodospirillum rubrum and Acetobacterium woodii enables anaerobic CO conversion to polyhydroxyalkanoates. Green Chemistry
- Olavarria, K., & Sousa, D. Z. (2024). Thermodynamic tools for more efficient biotechnological processes: an example in poly-(3-hydroxybutyrate) production from carbon monoxide. Current Opinion in Biotechnology, 90, Article 103212.
- Diender, M., Parera Olm, I., & Sousa, D. Z. (2021). Synthetic co-cultures: novel avenues for bio-based processes. Current Opinion in Biotechnology, 67, 72-79.
- Poehlein, A., Zeldes, B., Flaiz, M., Böer, T., Lüschen, A., Höfele, F., Baur, K. S., Molitor, B., Kröly, C., Wang, M., Zhang, Q., Fan, Y., Chao, W., Daniel, R., Li, F., Basen, M., Müller, V., Angenent, L. T., Sousa, D. Z., & Bengelsdorf, F. R. (2025). Advanced aspects of acetogens. Bioresource Technology, 427, Article 131913.