Author(s):
Rodrigues, Thomas ; Torres, Cristiana A.V. ; Marques, Susana ; Gírio, Francisco ; Freitas, Filomena ; Reis, Maria A.M.
Date: 2024
Persistent ID: http://hdl.handle.net/10362/179062
Origin: Repositório Institucional da UNL
Project/scholarship:
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDP%2F04378%2F2020/PT;
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDB%2F04378%2F2020/PT;
info:eu-repo/grantAgreement/FCT/Concurso para Atribuição do Estatuto e Financiamento de Laboratórios Associados (LA)/LA%2FP%2F0140%2F2020/PT;
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDB%2F50006%2F2020/PT;
info:eu-repo/grantAgreement/FCT/Concurso de avaliação no âmbito do Programa Plurianual de Financiamento de Unidades de I&D (2017%2F2018) - Financiamento Programático/UIDP%2F50006%2F2020/PT;
info:eu-repo/grantAgreement/FCT//2023.03035.BD/PT;
Subject(s): enzyme; hydrolysate; lignocellulose; polyhydroxyalkanoates; saccharification; Materials Science(all); Condensed Matter Physics
Description
Funding Information: This work was financed by national funds from FCT/MCTES\u2014Funda\u00E7\u00E3o para a Ci\u00EAncia e a Tecnologia, I.P., Minist\u00E9rio da Ci\u00EAncia, Tecnologia e Ensino Superior\u2014in the scope of the integrated project be@t (Textile Bioeconomy), which has received funding from the Environmental Fund through Component 12, Promotion of Sustainable Bioeconomy (Investment TC-C12-i01\u2014Sustainable Bioeconomy No. 02/C12-i01/202), of European funds allocated to Portugal by the Recovery and Resilience Plan (RRP) within the scope of the European Union\u2019s (EU\u2019s) Recovery and Resilience Mechanism, framed in the context of the Next-Generation EU for the period 2021\u20132026. Publisher Copyright: © 2024 by the authors.
In recent years, polyhydroxyalkanoates (PHAs) have gained notoriety because of their desirable properties that include proven biodegradability, biocompatibility, and thermal stability, which make them suitable alternatives to fossil-based polymers. However, the widespread use of PHAs is still challenging because of their production costs, which are greatly associated with the cultivation medium used for bacterial cultivation. In Portugal, one-quarter of the forest area is covered by Eucalyptus globulus wood, making its residues a cheap, abundant, and sustainable potential carbon source for biotechnological uses. In this work, eucalyptus bark was used as the sole feedstock for PHA production in a circular bioeconomic approach. Eucalyptus bark hydrolysate was obtained after enzymatic saccharification using Cellic® CTec3, resulting in a sugar-rich solution containing glucose and xylose. Although with differing performances, several bacteria were able to grow and produce PHA with distinct compositions, using the enzymatic hydrolysate as the sole carbon source. Pseudomonas citronellolis NRRL B-2504 achieved a high cellular growth rate in bioreactor assays (24.4 ± 0.15 g/L) but presented a low accumulation of a medium-chain-length PHA (mcl-PHA) comprising the monomers hydroxydecanoate (HD, 65%), hydroxydodecanoate (HDd, 25%), and hydroxytetradecanoate (HTd, 14%). Burkholderia thailandensis E264, on the other hand, reached a lower cellular growth rate (8.87 ± 0.34 g/L) but showed a higher biopolymer accumulation, with a polyhydroxybutyrate (PHB) content in the cells of 12.3 wt.%. The new isolate, Pseudomonas sp., revealed that under nitrogen availability, it was able to reach a higher accumulation of the homopolymer PHB (31 wt.%). These results, although preliminary, demonstrate the suitability of eucalyptus bark’s enzymatic hydrolysate as a feedstock for PHA production, thus offering an exciting avenue for achieving sustainable and environmentally responsible plastic products from an undervalued forestry waste.
