Matias, JoãoRodrigues, ThomasTorres, Cristiana A. V.Marques, SusanaRibeiro, BelinaGírio, FranciscoReis, Maria A.Freitas, Filomena2026-03-102026-03-102026-02Matias, J., Rodrigues, T., Torres, C., Marques, S. Ribeiro, B., Gírio, F., Reis, M., & Freitas, F. (2026). Sustainable Production of Poly(3-hydroxybutyrate) Using Eucalyptus Bark: Integration with Green Downstream Processing. In: ACS Sustainable Chemistry & Engineering, 2026, vol. 14 (7), p. 3749-3757. https://doi.org/10.1021/acssuschemeng.5c142432168-0485http://hdl.handle.net/10400.9/6297ABSTRACT: This study integrates the valorization of a lignocellulose material into poly(3-hydroxybutyrate), P(3HB), with biopolymer extraction from bacterial cells with the enzyme alcalase. The work focused on Burkholderia thailandensis DSM 13276 as the P(3HB) producer and on eucalyptus bark, a byproduct from the pulp industry, as the sole feedstock for bacterial cultivation. The eucalyptus bark was hydrolyzed by a cellulolytic enzymatic cocktail following steam explosion and further subjected to ultrafiltration for enzyme recovery. The resulting hydrolysate supported good cell growth, achieving a cell dry weight of 7.67 +/- 0.16 g/L within 72 h of cultivation, and high P(3HB) content (60.0 +/- 2.19 wt %) in the bacterial cells, clearly favoring biopolymer synthesis over cell growth, as demonstrated by the polymer and growth yields (0.190 gP(3HB)/gsugar and 0.026 gX/gsugar, respectively). High extraction efficiency (96%) and biopolymer purity (100 +/- 3.38%) were reached by enzymatic treatment, resulting in a sample with properties aligned with those of commercial P(3HB) in terms of molecular mass distribution, crystallinity, and thermal properties. These findings demonstrate the successful use of a sustainable feedstock together with the application of environmentally friendly technologies based on the use of enzymes for both lignocellulosic saccharification and biopolymer recovery to develop high-quality bioplastics, advancing the goals of a circular bioeconomy.engEucalyptus bark hydrolysateEucalyptus residuesEnzymatic hydrolysisLignocellulosic residuesEnzymatic saccharificationWaste valorizationCircular bioeconomyjournal article10.1021/acssuschemeng.5c14243