title: Biosynthesis and properties of medium-chain-length polyhydroxyalkanoates with enriched content of the dominant monomer.
abstract: When grown in a nonanoic acid-limited chemostat at a dilution rate of 0.25 h(-1), Pseudomonas putida KT2440 produced poly(3-hydroxynonanoate-co-3-hydroxyheptanoate) containing 68 mol % 3-hydroxynonanoate (C9) and 32 mol % 3-hydroxyheptanoate (C7). Under the same conditions, but in the presence of acrylic acid, a fatty acid β-oxidation inhibitor, the C9 monomer content increased to 88 mol %. Cofeeding glucose (3.9 g L(-1)) and nonanoic acid (2.9 ± 0.1 g L(-1)) in continuous culture with 0.2 g L(-1) of acrylic acid in the feed, further increased the C9 content to 95 mol %. A yield of PHA from nonanoic acid of 0.93 mol mol(-1) was attained. PHA with a 3-hydroxyoctanoate (C8) content of 98 mol % was produced with the same cofeeding methodology from octanoic acid. As the dominant monomer content increased, the melting point of the poly(3-hydroxynonanoate) copolymers increased from 46 to 63 °C and that of the poly(3-hydroxyoctanoate) copolymers from 54 to 62 °C. All copolymer compositions resulted in elongation to break values of about 1300%, but tensile strength at break and Young's modulus both increased with increasing amounts of the dominant monomer.
authors.affiliation: Department of Chemical Engineering, Queen's University, Kingston, Ontario, Canada K7L 3N6.
authors.forename: Xuan
authors.initials: X
authors.lastname: Jiang
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Sun
authors.forename: Robert H
authors.initials: RH
authors.lastname: Marchessault
authors.forename: Juliana A
authors.initials: JA
authors.lastname: Ramsay
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Ramsay
mesh_terms: D000179:Acrylates / Q000494:pharmacology; D055162:Biocatalysis; D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism; D019149:Bioreactors; D002210:Caprylates / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D055119:Elastic Modulus; D005227:Fatty Acids / Q000378:metabolism*; D005285:Fermentation / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D008422:Materials Testing; D054813:Polyhydroxyalkanoates / Q000819:agonists / Q000096:biosynthesis / Q000737:chemistry*; D016958:Pseudomonas putida / Q000187:drug effects / Q000378:metabolism*; D013718:Tensile Strength
chemical_list: D000179:Acrylates; D001672:Biocompatible Materials; D002210:Caprylates; D003470:Culture Media; D005227:Fatty Acids; D054813:Polyhydroxyalkanoates; C008776:pelargonic acid; D005947:Glucose; C036658:acrylic acid; C031492:octanoic acid