A team of researchers from the Biochemical Engineering Lab at UCIBIO - NOVA FCT has published a study in ACS Sustainable Chemistry & Engineering, demonstrating a "green" end-to-end process for producing a biodegradable alternative to petroleum-based plastics, poly(3-hydroxybutyrate) (P(3HB)).
The transition to a circular bioeconomy requires not only sustainable materials but also environmentally friendly production methods. In this published paper, entitled “Sustainable Production of Poly(3-hydroxybutyrate) Using Eucalyptus Bark: Integration with Green Downstream Processing”, UCIBIO researchers have successfully integrated the valorization of eucalyptus bark, a low-value byproduct of the pulp and paper industry, with a green extraction process to produce high-purity bioplastics.
Transforming Industrial Waste into Value
The study focused on using eucalyptus bark as the sole feedstock for the bacterium Burkholderia thailandensis. By applying steam explosion followed by enzymatic hydrolysis, the team converted the bark into a sugar-rich liquid. To make the process even more efficient, they used ultrafiltration to recover the enzymes for potential reuse.
The results were impressive: the bacterial cells achieved a P(3HB) content of 60%, showcasing a clear preference for polymer synthesis over cell growth. "In this work, we developed a more sustainable approach for producing the biodegradable bioplastic poly(3-hydroxybutyrate), P(3HB), using eucalyptus bark as a feedstock together with enzymatic downstream processing methods", explains Filomena Freitas, coordinator of the study.
A Cleaner Path to Recovery
One of the major bottlenecks in bioplastic production is the extraction phase, which traditionally relies on hazardous solvents like chloroform. The UCIBIO team overcame this by using alcalase, an enzyme, to recover the polymer from the bacterial cells. This green downstream processing achieved an extraction efficiency of 96% and a purity of 100%.
João Matias, the first author of the study and PhD student in the Biochemical Engineering Lab, notes that “the process ensures the material maintains high-quality standards. The final biopolymer showed properties, such as molecular mass and thermal behavior, consistent with commercial P(3HB) recovered via traditional chemical methods”.
Impact on the Circular Bioeconomy
This research marks a significant step forward in reducing the environmental footprint of bioplastics. By replacing fossil-derived feedstocks with industrial residues and eliminating toxic solvents, the team has provided a blueprint for cleaner manufacturing.
Filomena Freitas emphasizes the broader implications: "This study highlights the potential of combining biomass valorization with cleaner biopolymer recovery to support a more circular and sustainable bioeconomy."
The work also included contributions from researchers Thomas Rodrigues, Cristiana Torres, and Maria A.M. Reis, further solidifying the Biochemical Engineering Lab's role in developing innovative biotechnological solutions for global sustainability challenges. This research was developed in close collaboration with researchers from the Bioenergy and Biorrefineries Unit (LNEG).
Original Paper:
Matias, J., Rodrigues, T., Torres, C., & Freitas, F. (2026). Sustainable Production of Poly(3-hydroxybutyrate) Using Eucalyptus Bark: Integration with Green Downstream Processing. ACS Sustainable Chemistry & Engineering.
DOI: 10.1021/acssuschemeng.5c14243