title: Biosynthesis of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer by Cupriavidus sp. USMAA1020 isolated from Lake Kulim, Malaysia.
abstract: Cupriavidus sp. USMAA1020 was isolated from Malaysian environment and able to synthesize poly(3-hydroxybutyrate-co-4-hydroxybutyrate), [P(3HB-co-4HB)] when grown on gamma-butyrolactone as the sole carbon source. The polyester was purified from freeze-dried cells and analyzed by nuclear magnetic resonance (NMR) spectroscopy. 1H and 13C NMR results confirmed the presence of 3HB and 4HB monomers. In a one-step cultivation process, P(3HB-co-4HB) accumulation by Cupriavidus sp. USMAA1020 was affected by carbon to nitrogen ratio (C/N). A two-step cultivation process accumulated P(3HB-co-4HB) copolyester with a higher 4HB fraction (53 mol%) in nitrogen-free mineral medium containing gamma-butyrolactone. The biosynthesis of P(3HB-co-4HB) was also achieved by using 4-hydroxybutyric acid and alkanediol as 1,4-butanediol. The composition of copolyesters varied from 32 to 51 mol% 4HB, depending on the carbon sources supplied. The copolyester produced by Cupriavidus sp. USMAA1020 has a random sequence distribution of 3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB) units when analyzed by nuclear magnetic resonance (NMR) spectroscopy. When gamma-butyrolactone was used as the sole carbon source, the 4HB fraction in copolyester increased from 25 to 60 mol% as the concentration of gamma-butyrolactone in the culture medium increased from 2.5 g/L to 20.0 g/L.
authors.affiliation: School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia. amirul@usm.my
authors.forename: A A
authors.initials: AA
authors.lastname: Amirul
authors.forename: A R M
authors.initials: AR
authors.lastname: Yahya
authors.forename: K
authors.initials: K
authors.lastname: Sudesh
authors.forename: M N M
authors.initials: MN
authors.lastname: Azizan
authors.forename: M I A
authors.initials: MI
authors.lastname: Majid
mesh_terms: D015107:4-Butyrolactone / Q000494:pharmacology; D002244:Carbon / Q000494:pharmacology; D049921:Cupriavidus / Q000187:drug effects / Q000254:growth & development / Q000302:isolation & purification*; D005618:Fresh Water / Q000382:microbiology*; D006885:Hydroxybutyrates / Q000378:metabolism*; D008296:Malaysia; D011091:Polyesters / Q000378:metabolism*; D000094122:Polyhydroxybutyrates
chemical_list: D015107:4-Butyrolactone; D002244:Carbon; D006885:Hydroxybutyrates; D011091:Polyesters; C068056:poly(3-hydroxybutyrate-co-4-hydroxybutyrate); D000094122:Polyhydroxybutyrates