• Proceedings of the Korean Fiber Society Conference
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• 1998.04a
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• pp.45-49
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• 1998

The production of unsaturated poly(3-hydroxyalkanoate)s, PHAs, by Pseudomonas oleovorans has been studied extensively in this laboratory$\^$1-3/, and recently a procedure has been developed for the quantitative conversion of the unsaturated groups to epoxide groups$^4$.(omitted)

• Polymer(Korea)
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• v.27 no.6
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• pp.536-541
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• 2003

Unsaturated poly(3-hydroxyalkanoate) (UPHA) was biosynthesized and the properties of drug delivery using the polymer matrix were investigated. The biosynthesis of UPHA was carried out by pH-stat fed batch fermentation of Pseudomonas oleovorans (ATCC 29347) grown solely with 10-undecenoic acid as a carbon source. The physical and chemical properties of the biosynethesized UPHA were characterized using NMR, FT-IR, GPC and DSC. The drug release experiments were carried out using HPLC with a diffusion cell fur the release amount of ketoprofen as model drug. The effects of crosslinking degree, patch thickness, and enhancer on the drug release were studied. The drug release rate was linearly decreased and consistent with increased crosslinking degree of the polymer matrix. The duration of drug release was enhanced by the Increased patch thickness. The drug release rate was increased with increased amount of propylene gylcol as an enhancer.

• Polymer(Korea)
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• v.27 no.6
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• pp.542-548
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• 2003

Nanoparticles with unsaturated poly(hydroxyalkanoate)s (UPHAs) biosynthesized with Pseudo-monas oleovorans were prepared by spontaneous emulsification solvent diffusion method. The influence of nanoparticle formation was investigated with various experimental parameters such as sonication conditions, sol-vent, surfactant and polymer contents, etc. The physical and chemical properties of UPHAS and its nanoparticles were characterized using $^1$H- and $\^$13/C-nuclear magnetic resonance spectroscopies, attenuated total reflection infrared spectroscopy, differential scanning calorimetry and gel permeation chromatography. The morphology of particles was observed using scanning electron microscope and the size and distribution of nanoparticles were measured with electrophoretic light scattering spectrophotometer. The mean diameter of particles decreased with increasing sonication amplitude and time. The addition of ethanol into UPHAS chloroform solution decreased the particle size presumably due to increased solvent diffusion into water phase. The particle size increased with increased the concentration of UPHAS solution. Under the 2-4％ poly(vinyl alcohol) (PVA) aqueous solution the minimum mean diameter of particles was shown. The higher degree of hydrolysis and degree of polymerization of PVA increased the mean diameter of particles.

• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.518-521
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• 2002

Poly(3-hydroxyalkanoate) copolyesters containing both carbon-carbon double and carbon-carbon triple bonds were produced by Pseudomonas oleovorans grown in mixtures of 10-undecynoic acid (10-UND($\equiv$)) and 10-undecenoic acid (10-UND(=)). The PHA content in the dry cells was usually 40 wt%. The bioconversion yield of ($10-UND({\equiv})$) to PHA by P. oleovorans was remarkably enhanced from 1% to over 24% as the fraction of 10-UND(=) in the carbon substrate mixtures increased from 0 to 50%. These values were higher than those obtained when P. oleovorans was grown in the same molar mixtures of ($10-UND({\equiv})$) and nonanoic acid (NA), indicating that 10-UND(=) was more efficient than NA as a cosubstrate in inducing cometabolic PHA production.

• Journal of Microbiology and Biotechnology
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• v.13 no.1
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• pp.64-69
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• 2003

Pseudomonas chlororaphis HS21 was isolated from a soil sample and found to produce medium-chain-length polyhydroxyalkanoates (MCL-PHAs) using palm kernel oil (PKO) as the sole carbon source. Up to 3.3 g/1 dry cell weight containing $45\%$ MCL-PHA was produced, when the strain was grown for 21 h in a jar fermentor culture containing 5 g/1 PKO. The polymer produced from PKO consisted of unsaturated monomers of $7.3\%$ 3-hydroxy-5-cis-tetradecenoate and $2.3\%$ 3-hydroxy-5,8,-cis, cis-tetradecadienoate as well as saturated even-carbon number monomers ranging from $C_6\;to\;C_14$, as determined by GC and El GC/MS The PHA was a transparent, sticky material at room temperature. A differential scanning calorimetric analysis revealed that the polymer was amorphous with a $-44^{\circ}C$ glass transition temperature. The number average molecular weight and polydispersity index of the PHA were 83,000 and 1.53, respectively. Although the PHA was practically biodegradable, its degradability was lower than that of poly(3-hydroxyoctanoate) based on a comp:trison of the clear zones formed by growing PHA depolymerase-producing bacteria on an agar plate containing the respective polymers.