Author(s): Pereira, João R. ; Araújo, Diana ; Freitas, Patrícia ; Marques, Ana C. ; Delgado Alves, Vitor ; Sevrin, Chantal ; Grandfils, Christian ; Fortunato, Elvira ; Reis, Maria A.M. ; Freitas, Filomena
Date: 2021
Persistent ID: http://hdl.handle.net/10400.5/23782
Origin: Repositório da Universidade de Lisboa
Subject(s): 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
