• Title/Summary/Keyword: Polyhydroxyalkanoates

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Mcl-PHAs Produced by Pseudomonas sp. Gl01 Using Fed-Batch Cultivation with Waste Rapeseed Oil as Carbon Source

  • Mozejko, Justyna;Wilke, Andreas;Przybylek, Grzegorz;Ciesielski, Slawomir
    • Journal of Microbiology and Biotechnology
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    • v.22 no.3
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    • pp.371-377
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    • 2012
  • The present study describes medium-chain-length polyhydroxyalkanoates (mcl-PHAs) production by the Pseudomonas Gl01 strain isolated from mixed microbial communities utilized for PHAs synthesis. A two-step fed-batch fermentation was conducted with glucose and waste rapeseed oil as the main carbon source for obtaining cell growth and mcl-PHAs accumulation, respectively. The results show that the Pseudomonas Gl01 strain is capable of growing and accumulating mcl-PHAs using a waste oily carbon source. The biomass value reached 3.0 g/l of CDW with 20% of PHAs content within 48 h of cultivation. The polymer was purified from lyophilized cells and analyzed by gas chromatography (GC). The results revealed that the monomeric composition of the obtained polyesters depended on the available substrate. When glucose was used in the growth phase, 3-hydroxyundecanoate and 3-hydroxydodecanoate were found in the polymer composition, whereas in the PHAs-accumulating stage, the Pseudomonas Gl01 strain synthesized mcl-PHAs consisting mainly of 3-hydroxyoctanoate and 3-hydroxydecanoate. The transcriptional analysis using reverse-transcription real-time PCR reaction revealed that the phaC1 gene could be transcribed simultaneously to the phaZ gene.

Preparation of enantiomerically pure (R)-3-hydroxybutyrate

  • Lee, Yeong;Lee, Sang-Yeop
    • 한국생물공학회:학술대회논문집
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    • 2000.04a
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    • pp.579-582
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    • 2000
  • Enantiomerically pure hydroxycarboxylic acids have great potential as chiral building blocks in fine chemicals due to their easily modificable two functional groups. Microbial polyhydroxyalkanoates (PHAs) can have more than one hundred of hydroxycarboxylic acids as monomeric constituents by growing cells under various conditions. All of the monomeric constituents are enantiomerically pure in (R)-conformation if there is a chiral center. Therefore, efficient production of enantiomerically pure hydroxycarboxylic acids by degrading PHAs is possible. In this presentation, we report on the development of a novel method for the preparation of (R)-hydroxybutyric acid by in vivo depolymerization of Polyhydroxybutyrae.

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In Vivo Analysis of fadB Homologous Enzymes Involved in Biosynthesis of Polyhydroxyalkanoates in Recombinant Escherichia coli (재조합 대장균에서 fadB 유사효소의 Polyhydroxyalkanoates 합성에 미치는 역할의 규명)

  • 최종일;박시재;이상엽
    • KSBB Journal
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    • v.19 no.4
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    • pp.331-334
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    • 2004
  • In vivo characterization of FadB homologous enzymes including PaaG, YdbU and YgfG for medium-chain-length (MCL) polyhydroxyalkanoate (PHA) biosynthesis was carried out in fadB mutant Escherichia coli. Previously, it was reported that amplification of FadB homologous enzymes such as PaaG and YdbU in fadB mutant E. coli resulted in enhanced biosynthesis of MCL-PHA by greater than two fold compared with control strain. In this study, we constructed paaG fadB double mutant E. coli WB114 and ydbU fadB double mutant E. coli WB115 to investigate the roles of PaaG and YdbU in biosynthesis of MCL-PHA. Inactivation of paaG and ydbU genes in fadB mutant E. coli harboring Pseudomonas sp. 61-3 phaC2 gene reduced the MCL-PHA production to 0.16 and 0.16 PHA g/L, respectively from 2 g/L of sodium decanoate, which are much lower than 0.43 PHA g/L obtained with fadB mutant E. coli WB101 harboring the phaC2 gene. Also, we identified new FadB homologous enzyme YgfG, and examined its roles by overexpression of ygfG and construction of ygfG fadB double mutant E. coli WB113.

Production of Polyhydroxybutyrate from Crude Glycerol and Spent Coffee Grounds Extract by Bacillus cereus Isolated from Sewage Treatment Plant

  • Lee, Gi Na;Choi, So Young;Na, Jonguk;Youn, HaJin;Jang, Yu-Sin
    • KSBB Journal
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    • v.29 no.6
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    • pp.399-404
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    • 2014
  • Production of biodegradable polymer polyhydroxyalkanoates (PHAs) from industrial wastes exhibits several advantages such as recycle of waste and the production of high valuable products. To this end, this study aimed at isolating from the sewage treatment plant a PHA producing bacterium capable of utilizing wastes generated from biodiesel and food industries. A Bacillus cereus strain capable of producing poly(3-hydroxybutyrate) [P(3HB)] was isolated, which was followed by confirmation of P(3HB) accumulation by gas-chromatographic analyses. Then, the effects of nutrient limitation on P(3HB) production by B. cereus was first examined. Cells cultured in a minimal medium under the limitation of nitrogen, potassium and sulfur suggested that nitrogen limitation allows the highest P(3HB) accumulation. Next, production of P(3HB) was examined from both waste of biodiesel production (crude glycerol) and waste from food industry (spent coffee grounds). Cells cultured in nitrogen-limited minimal medium supplemented crude glycerol and waste spent coffee grounds extract accumulated P(3HB) to the contents of 2.4% and 1.0% of DCW. This is the first report demonstrating the capability of B. cereus to produce P(3HB) from waste raw materials such as crude glycerol and spent coffee grounds.

Complete Genome Sequence of Massilia sp. KACC 81254BP Reveals a Potential for Degrading Polyhydroxyalkanoates

  • Sihyun An;Gyeongjun Cho;Jae-Hyung Ahn;Hang-Yeon Weon;Dayeon Kim;Young-Joon Ko;Jehyeong Yeon;Joon-hui Chung;Han Suk Choi;Jun Heo
    • Microbiology and Biotechnology Letters
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    • v.52 no.1
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    • pp.102-104
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    • 2024
  • Massilia sp. KACC 81254BP, isolated from a landfill on Jeju Island, Republic of Korea, possesses the capability to degrade polyhydroxyalkanoates (PHAs). The genomic analysis of strain KACC 81254BP consists of a circular chromosome comprising 5,028,452 base pairs with a DNA G+C content of 64.6%. This complete genome consists of a total of 4,513 genes, including those encoding the PHA degradation enzyme (PhaZ). This study offers valuable genomic insights into the enzymes responsible for degrading polyester plastics.

High Cell Density Cultivation of Pseudomonas oleovorans for the Production of Poly(3-Hydroxyalkanoates)

  • Lee, Sang-Yup
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.1 no.1
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    • pp.51-53
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    • 1996
  • Fed-batch culture of Pseudomonas oleovorans was carried out for the production of medium-chain-length polyhydroxyalkanoates (MCL-PHAs) using octanoate as a carbon source. Octanoate and the salt solution containing ammounium sulfate and magnesium sulfate were intermittently fed in the course of fermentation. Cell mass and PHA concentrations of 42.8 and 16.8g/L, respectively, could be obtained in 40 h. The PHA content and the PHA productivity were 39.2% and 0.42 g PHA/L-h, respectively. The yields of cell mass and PHA were 0.71 g dry cell mass/g octanoate and 0.28g PHA/g octanoate, respectively. Therefore, octanoate can be used for the production of MCL-PHAs to a high concentration with high productivity.

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Isolation of an Aromatic Polyhydroxyalkanoates-degrading Bacterium

  • JU, HE-SUG;JUNGHO KIM;HOON KIM
    • Journal of Microbiology and Biotechnology
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    • v.8 no.5
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    • pp.540-542
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    • 1998
  • Five microorganisms capable of degrading an aromatic medium-chain-length polyhydroxyalkanoate ($PHA_{MCL}$), poly(3-hydroxy-5-phenylvalerate) (PHPV), were isolated from wastewater-treatment sludge. Among the isolates, JS02 showed degrading activity consistantly during several transfers. The isolate JS02 could hydrolyze another aromatic MCL copolyester, poly(3-hydroxy-5-phenoxyvalerate-co-3-hydroxy-7-phenoxyheptanoate), [P(5POHV-co-7POHH)], and other short-chain-length PHAs ($PHA_{SCL}) such as poly(3-hydroxybutyrate) [P3(HB)], poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3 HB-co-4 HB)], and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] with relatively low activity. The culture supernatant of JS02 showed hydrolyzing activity for the p-nitrophenyl esters of fatty acids.

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Biocompatibility of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Copolyesters Produced by Alcaligenes sp. MT-16

  • Choi, Gang-Guk;Kim, Hyung-Woo;Kim, Young-Baek;Rhee, Young-Ha
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.10 no.6
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    • pp.540-545
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    • 2005
  • Poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3HB-co-3HV), copolyesters, with 3-hydroxyvalerate (3HV) contents ranging from 17 to 60 mol%, were produced by Alcaligenes sp. MT-16, and their biocompatibility evaluated by the growth of Chinese hamster ovary (CHO) cells and the adsorption of blood proteins and platelets onto their film surfaces. The number of CHO cells that adhered to and grew on these films was higher with increasing 3HV content. In contrast, the tendency for blood proteins and platelets to adhere to the copolyester surfaces significantly decreased with increasing 3HV content. Examination of the surface morphology using atomic force microscopy revealed that the surface roughness was an important factor in determining the biocompatibility of theses copolyesters. The results obtained in this study suggest that poly(3HB-co-3HV) copolyesters, with >30 mol% 3HV, may be useful in biocompatible biomedical applications.

Drug Release Characteristics of Biodegradable Polymers for Stent Coating (스텐트 코팅용 생분해성 고분자의 약물 방출 특성)

  • 강혜수;김진설;김동운;강병철;이봉희;김범수
    • KSBB Journal
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    • v.18 no.2
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    • pp.107-110
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    • 2003
  • Biodegradable polymers, poly(lactic-co-glycolic acid) (PLGA), poly(3-hydroxybutyrate) (PHB), and medium chain length polyhydroxyalkanoates (MCL-PHA) containing rose bengal (model drug) were coated onto the surface of stainless steel (stent materials) and their in vitro release characteristics were investigated. Drug release increased with; decreasing PLGA concentration, increasing rose bengal concentration, and Increasing dip-coating duration. The order of drug release from the polymer coating was: PHB > PLGA > MCL-PHA. These results suggest that drug release can be controlled by: changing the concentration and type of polymer, the drug concentration, and the dip-coating duration.