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

• Published in: International journal of biological macromolecules Vol. 167; pp. 85 - 92
• Main Authors: Pereira, João R., Araújo, Diana, Freitas, Patrícia, Marques, Ana C., Alves, Vítor D., Sevrin, Chantal, Grandfils, Christian, Fortunato, Elvira, Reis, Maria A.M., Freitas, Filomena
• Format: Journal Article Web Resource
• Language: English
• Published: Netherlands Elsevier B.V 15.01.2021; Elsevier
• Subjects: 3-hydroxybutyric acid; apple pulp; Biopolymer; Biopolymers - chemistry; Bioreactors; Chemical Fractionation; Chemical Phenomena; crystal structure; drugs; electron microscopy; Engineering, computing & technology; Fermentation; Fruit - chemistry; Fruit pulp waste; glass transition; industry; Ingénierie, informatique & technologie; juices; Kinetics; Malus; Materials science & engineering; Mechanical Phenomena; Medical; medicine; Molecular Weight; Pharmaceutical; polyhydroxyalkanoates; Polyhydroxyalkanoates (PHA); Polyhydroxyalkanoates - biosynthesis; Polyhydroxyalkanoates - chemistry; Polyhydroxyalkanoates - isolation & purification; Pseudomonas - metabolism; Pseudomonas chlororaphis; Science des matériaux & ingénierie; temperature; Waste Products; wastes; Mn; PLA; PHA; Mw; Xc; mcl-PHA; 3HDd; 3HD; Fruit pulp waste; Polyhydroxyalkanoates (PHA); Tg; n. a; PDI; Tdeg; n. d; Tm; Pseudomonas chlororaphis; 3HO; scl-PHA; P(3HB); 3HHx; 3HTd
• ISSN: 0141-8130; 1879-0003; 1879-0003
• DOI: 10.1016/j.ijbiomac.2020.11.162

Pseudomonas chlororaphis subsp. aurantiaca DSM 19603 was cultivated on apple pulp, a glucose- and fructose-rich 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 ± 0.1 mol% 3-hydroxydecanoate, 17.9 ± 1.0 mol% 3-hydroxyoctanoate, 14.5 ± 1.1 mol% 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 low crystallinity index (12.7 ± 2.7%), a molecular weight (Mw) of 1.34 × 105 ± 0.18 × 105 Da and a polydispersity index of 2.70 ± 0.03. The biopolymer's films were dense and had a smooth surface, as demonstrated by Scanning Electron Microscopy. 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.