Comonomer‐Unit Compositions, Physical Properties and Biodegradability of Bacterial Copolyhydroxyalkanoates

Feng, Lidan; Yoshie, Naoko; Asakawa, Naoki; Inoue, Yoshio

doi:10.1002/mabi.200300092

Cited by 41 publications

(38 citation statements)

References 31 publications

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“…Normally, a random copolymer has a D value of 1.0, while block and alternative copolymers have a D value larger and lower than 1, respectively. [5,33] Figure 1a and 1b show the 13 C spectra of the P[3HB-co-(19.7 mol-% 3MP)] and P[3HB-co-(18.8 mol-% 3HP)] sample, respectively. The relative intensities of respective diad peaks of P(3HB-co-3MP) and P(3HB-co-3HP) are shown in Figure 1a and 1b, respectively.…”

Section: Resultsmentioning

confidence: 99%

Mechanical Properties of Comonomer‐Compositionally Fractionated Poly[(3‐hydroxybutyrate)‐co‐(3‐mercaptopropionate)] with Low 3‐Mercaptopropionate Unit Content

Fang

Dong

Zhu

et al. 2007

Macromolecular Bioscience

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The mechanical properties, such as Young's modulus, yield strength, and the elongation at breakage, were investigated for several sulfur-containing biopolymers P(3HB-co-3MP). A series of P(3HB-co-3MP) samples with 3MP unit content ranging from 6.6 to 39.1 mol-% was biosynthesized by fermentation using the PHA-synthesizing bacteria Cupriavidus necator. For comparison, the bacterially synthesized P(3HB) and P(3HB-co-3HP) with the 3HP unit content ranging from 13.1 to 21.1 mol-% were also investigated. It was found that the sulfur-containing P(3HB-co-3MP) is much more durable to stretching. Notably, P(3HB-co-3MP) with the 3MP unit content of only 6.6 mol-% was found to show excellent mechanical properties.

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Section: Resultsmentioning

confidence: 99%

Mechanical Properties of Comonomer‐Compositionally Fractionated Poly[(3‐hydroxybutyrate)‐co‐(3‐mercaptopropionate)] with Low 3‐Mercaptopropionate Unit Content

Fang

Dong

Zhu

et al. 2007

Macromolecular Bioscience

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“…3,7,20,21 To clarify exclusively the comonomer compositional dependent physical properties and biodegradation behavior, biosynthesized P(3HB-co-3MP)s with 18-28 mol % 3MP unit were well fractionated by the solvent-nonsolvent technique into a series of P(3HB-co-3MP) fractions with different 3MP unit content and much narrow comonomer compositional distribution. 15 Totally, eight fractions with 3MP unit content varying from 2.9 to 61.2 mol % were selected as samples for this research.…”

Section: Resultsmentioning

confidence: 99%

Enzymatic Hydrolysis of Thioester Linkages in Bacterial Poly(3-hydroxybutyrate-co-3-mercaptopropionate)s by Poly(3-hydroxybutyrate) Depolymerase Isolated from Ralstonia pickettii T1

Zhu

Tanaka

Feng

et al. 2005

Polym J

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KEY WORDSPoly(3-hydroxybutyrate-co-3-mercaptopropionate) / Enzymatic Degradation / Thioester / [DOI 10.1295/polymj.37.711] One of major approaches to modify the bacterial poly(3-hydroxybutyrate) (PHB) while reserving its biodegradability has involved the copolymerization of its monomer with some hydroxyalkanoates (HA) via bacterial fermentation, 1 comprising 3-, 4-, 5-and 6-hydroxyalkanoates with various length of the mainchain or various substituents at different positions, such as 3-hydroxypropionate (3HP), 2-5 3-hydroxyvalerate (3HV) 6,7 and so forth. Recently, Steinbüchel's group [8][9][10][11][12][13][14] has succeeded to isolate a novel class of biopolymers from the poly-(hydroxyalkanoate) (PHA)-accumulating bacterium, comprising one kind of completely different backbone constituents, that is, thioesters, such as poly(3-mercaptopropionate), poly(3-mercaptobutyrate), poly(3-mercaptovalerate), poly(3-hydroxybutyrate-co-3-mercaptopropionate) [P(3HB-co-3MP)] and poly(3-hydroxybutyrate-co-3-mercaptobutyrate).Physical properties, such as solubility, crystallinity and thermal stability, of the biodegradable polymers are modified with the introduction of thioester linkages. 8,15 However, few research have been devoted to the enzymatic hydrolysis of thioester linkages in P(3HB-co-3MP) except for the work most recently published. 16 It is found that the PHA depolymerase isolated from Schlegelella thermodepolymerans is specific for the oxoester linkages and that thioester linkages can not be cleaved by the enzyme. PHA depolymerases are known to be quite specific to the chemical structure and physical state of polyesters. It seems necessary to investigate further the enzymatic hydrolyzability of the thioester linkages with considering the possible substrate specificity of depolymerase. PHA depolymerase isolated from Ralstonia pickettii T1 (PhaZRpi) has been well purified and characterized, and thus is one ideal enzyme to study the degradation of P(3HB-co-3MP)s.In this communication, the enzymatic degradability of thioester linkages in the comonomer compositionally well-fractionated P(3HB-co-3MP)s by PHA depolymerase PhaZRpi is evidenced by analyzing degradation products. It is the first observation of the degradation of thioester linkages by PHA depolymerase. Moreover, in comparison with P(3HB-co-3HP)s, the comonomer compositional dependence of the enzymatic degradability will be established. EXPERIMENTAL Materials and Preparation of SamplesP(3HB) 17 and P(3HB-co-3MP)s 10-13,15 were synthesized by using Ralstonia eutropha H16. Films for the enzymatic degradation were compression-molded at 195 C for 5 min under a pressure of 5 MPa, using Toyoseiki Mini Test Press-10, and then quenched to 30 C for crystallization of at least 4 weeks. The enzyme was isolated from Ralstonia pickettii T1. 19 Analytical ProceduresWide-angle X-ray diffraction (WAXD) measurements were carried out on a Rigaku RINT-2000

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“…The existence of PE segments is due to the excess insertion of PO into the PPC backbone. Based on the chloroform/n-heptane mixtures, [38,39,42] the PPC-PO sample was fractionated according to difference in molecular weight and composition. Fractions A1»A9 were characterized by 1 H NMR and GPC analyses and the results are shown in Table 1.…”

Section: Resultsmentioning

confidence: 99%

“…Fractions were obtained by repeating the addition of n-heptane. [35][36][37][38][39] Each fraction was re-dissolved in chloroform solution with stirring for 1 h at 25 C in a conical flask, and then transferred to a glass dish to completely evaporate the chloroform solvent. The resulting films were stored for at least three weeks in a vacuum drying oven at 35 C before characterizing.…”

Section: Sample Preparationmentioning

confidence: 99%

Studies on Comonomer Compositional Distribution of Poly(propylene carbonate-propylene oxide) Copolymer and Its Effect on the Thermal, Mechanical and Oxygen Barrier Properties of Fractions

Yun

Zhang

Jin

et al. 2015

Journal of Macromolecular Science, Part B

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Poly(propylene carbonate) (PPC) was synthesized by the alternating copolymerization of carbon dioxide and propylene oxide (PO). However, during the polymerization, two by-products tended to produce cyclic propylene carbonate (CPC) and a polyether (PE) segment. The excess PO repeat units (PE segment) can easily insert into the PPC backbone and eventually produce the PPC-PO copolymer. The production of CPC and PE segments affected the increase of polymer chain length. In order to investigate the effects of the existence of PE segments, CPC, and molecular weight of fractions on the physical properties of PPC-PO copolymer, a series of fractions with narrow molecular weight distribution were obtained by repeated fractionation. Based on a solvent/non-solvent (chloroform/n-heptane) mixture, an original PPC-PO sample was fractionated into nine fractions with number-average molecular weights (M n ) from 0.34 £ 10 5 to 5.56 £ 10 5 and PE content from 0.4 to 15 mol%. The M n of PPC-PO fractions decreased with the increase of PE content in the PPC-PO backbone, and the thermal and mechanical properties of the PPC-PO copolymers were affected by their M n and PE contents. Furthermore, the lower the PE content, the higher the M n value. Higher M n means better tensile and lower oxygen permeability of PPC-PO copolymer.

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Comonomer‐Unit Compositions, Physical Properties and Biodegradability of Bacterial Copolyhydroxyalkanoates

Cited by 41 publications

References 31 publications

Mechanical Properties of Comonomer‐Compositionally Fractionated Poly[(3‐hydroxybutyrate)‐co‐(3‐mercaptopropionate)] with Low 3‐Mercaptopropionate Unit Content

Mechanical Properties of Comonomer‐Compositionally Fractionated Poly[(3‐hydroxybutyrate)‐co‐(3‐mercaptopropionate)] with Low 3‐Mercaptopropionate Unit Content

Enzymatic Hydrolysis of Thioester Linkages in Bacterial Poly(3-hydroxybutyrate-co-3-mercaptopropionate)s by Poly(3-hydroxybutyrate) Depolymerase Isolated from Ralstonia pickettii T1

Studies on Comonomer Compositional Distribution of Poly(propylene carbonate-propylene oxide) Copolymer and Its Effect on the Thermal, Mechanical and Oxygen Barrier Properties of Fractions

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