title: Biosynthesis of poly(3-hydroxybutyrate) copolymers by Azotobacter chroococcum 7B: A precursor feeding strategy.
abstract: A precursor feeding strategy for effective biopolymer producer strain Azotobacter chroococcum 7B was used to synthesize various poly(3-hydroxybutyrate) (PHB) copolymers. We performed experiments on biosynthesis of PHB copolymers by A. chroococcum 7B using various precursors: sucrose as the primary carbon source, various carboxylic acids and ethylene glycol (EG) derivatives [diethylene glycol (DEG), triethylene glycol (TEG), poly(ethylene glycol) (PEG) 300, PEG 400, PEG 1000] as additional carbon sources. We analyzed strain growth parameters including biomass and polymer yields as well as molecular weight and monomer composition of produced copolymers. We demonstrated that A. chroococcum 7B was able to synthesize copolymers using carboxylic acids with the length less than linear 6C, including poly(3-hydroxybutyrate-co-3-hydroxy-4-methylvalerate) (PHB-4MHV) using Y-shaped 6C 3-methylvaleric acid as precursor as well as EG-containing copolymers: PHB-DEG, PHB-TEG, PHB-PEG, and PHB-HV-PEG copolymers using short-chain PEGs (with n ≤ 9) as precursors. It was shown that use of the additional carbon sources caused inhibition of cell growth, decrease in polymer yields, fall in polymer molecular weight, decrease in 3-hydroxyvalerate content in produced PHB-HV-PEG copolymer, and change in bacterial cells morphology that were depended on the nature of the precursors (carboxylic acids or EG derivatives) and the timing of its addition to the growth medium.
authors.affiliation: a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia.|b Faculty of Biology , Moscow State University , Moscow , Russia.|c Department of Maxillofacial and Oral Surgery , Nizhny Novgorod State Medical Academy , Nizhny Novgorod , Russia.
authors.forename: A P
authors.initials: AP
authors.lastname: Bonartsev
authors.affiliation: b Faculty of Biology , Moscow State University , Moscow , Russia.
authors.forename: I I
authors.initials: II
authors.lastname: Zharkova
authors.affiliation: a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia.|c Department of Maxillofacial and Oral Surgery , Nizhny Novgorod State Medical Academy , Nizhny Novgorod , Russia.
authors.forename: S G
authors.initials: SG
authors.lastname: Yakovlev
authors.affiliation: a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia.
authors.forename: V L
authors.initials: VL
authors.lastname: Myshkina
authors.affiliation: a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia.
authors.forename: T K
authors.initials: TK
authors.lastname: Mahina
authors.affiliation: b Faculty of Biology , Moscow State University , Moscow , Russia.|c Department of Maxillofacial and Oral Surgery , Nizhny Novgorod State Medical Academy , Nizhny Novgorod , Russia.
authors.forename: V V
authors.initials: VV
authors.lastname: Voinova
authors.affiliation: a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia.|c Department of Maxillofacial and Oral Surgery , Nizhny Novgorod State Medical Academy , Nizhny Novgorod , Russia.
authors.forename: A L
authors.initials: AL
authors.lastname: Zernov
authors.affiliation: a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia.|c Department of Maxillofacial and Oral Surgery , Nizhny Novgorod State Medical Academy , Nizhny Novgorod , Russia.
authors.forename: V A
authors.initials: VA
authors.lastname: Zhuikov
authors.affiliation: a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia.
authors.forename: E A
authors.initials: EA
authors.lastname: Akoulina
authors.affiliation: b Faculty of Biology , Moscow State University , Moscow , Russia.
authors.forename: E V
authors.initials: EV
authors.lastname: Ivanova
authors.affiliation: b Faculty of Biology , Moscow State University , Moscow , Russia.
authors.forename: E S
authors.initials: ES
authors.lastname: Kuznetsova
authors.affiliation: b Faculty of Biology , Moscow State University , Moscow , Russia.
authors.forename: K V
authors.initials: KV
authors.lastname: Shaitan
authors.affiliation: a A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences , Moscow , Russia.
authors.forename: G A
authors.initials: GA
authors.lastname: Bonartseva
mesh_terms: D001395:Azotobacter / Q000378:metabolism*; D002850:Chromatography, Gel; D006885:Hydroxybutyrates / Q000737:chemistry / Q000378:metabolism*; D008970:Molecular Weight; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism*; D066244:Proton Magnetic Resonance Spectroscopy; D000094122:Polyhydroxybutyrates
chemical_list: D006885:Hydroxybutyrates; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates
keywords: Azotobacter chroococcum 7B; biosynthesis; poly(3-hydroxyalkanoates); poly(3-hydroxybutyrate); poly(ethylene glycol); precursor feeding