Production of medium-chain-length polyhydroxyalkanoates by Pseudomonas chlororaphis subsp. aurantiaca: Cultivation on fruit pulp waste and polymer characterization

• Autor(a) principal: Pereira, João R.
• Data de Publicação: 2021
• Outros Autores: Araújo, Diana, Freitas, Patrícia, Marques, Ana C., Delgado Alves, Vitor, Sevrin, Chantal, Grandfils, Christian, Fortunato, Elvira, Reis, Maria A.M., Freitas, Filomena
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.5/23782
• topic: fruit pulp waste; polyhydroxyalkanoates (PHA); Pseudomonas chlororaphis

Pseudomonas chlororaphis subsp. aurantiaca DSM 19603 was cultivated on apple pulp, a glucose- and fructoserich waste generated during juice production, to produce medium-chain length polyhydroxyalkanoates. A cell dry mass of 8.74 ± 0.20 g/L, with a polymer content of 49.25 ± 4.08% were attained. The produced biopolymer was composed of 42.7±0.1mol% 3-hydroxydecanoate, 17.9±1.0mol% 3-hydroxyoctanoate, 14.5±1.1mol% 3- hydroxybutyrate, 11.1±0.6 mol% 3-hydroxytetradecanoate, 10.1±0.5 mol% 3-hydroxydodecanoate and 3.7± 0.2 mol% 3-hydroxyhexanoate. It presented low glass transition and melting temperatures (−40.9 ± 0.7 °C and 42.0±0.1 °C, respectively), and a degradation temperature of 300.0±0.1 °C, coupled to a lowcrystallinity index (12.7±2.7%), amolecularweight (Mw) of 1.34 × 105±0.18×105 Da and a polydispersity index of 2.70±0.03. The biopolymer's filmswere dense and had a smooth surface, as demonstrated by Scanning ElectronMicroscopy. They presented a tension at break of 5.21 ± 1.09 MPa, together with an elongation of 400.5 ± 55.8% and an associated Young modulus of 4.86 ± 1.49 MPa, under tensile tests. These attractive filming properties of this biopolymer could potentially be valorised in several areas such as the fine chemicals industry, biomedicine, pharmaceuticals, or food packaging