• Title, Summary, Keyword: poly(3-hydroxybutyric acid)

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Production of Poly-3-Hydroxyalkanhoate by Haloarcular sp. EH-1 (Haloarcular sp. EH-1으로부터 생분해성 Poly-3-Hydroxyalkanoate의 생산)

  • 정명주;박형숙
    • Journal of Life Science
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    • v.9 no.6
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    • pp.737-742
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    • 1999
  • The extremely halophilic archaebacterium Haloarcular sp. EH-1 was isolated from solar salts. Haloarcular sp. EH-1 accumulated poly(3-hydroxyalkanoate) (PHA) as intracellular granules. PHA production in batch culture have been studied. The PHA was identified as poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHB/HV) of 3-hydroxybutyric acid and 3-hydroxyvaleric acid by the analysis of GC, IR and NMR. The melting temperature of PHB/HV was 152.46$^{\circ}C$, viscosity was 1.25 ㎗/g, and molecular weight was $1.44 X 10^5.$

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Effect of Growth Temperature and Nutritional Components on the Synthesis of Poly-3-Hydroxybutyric Acid by Filamentation-Suppressed Recombinant Escherichaia coli (Filamentation이 억제된 재조합 대장균에 의한 Poly-3-Hydroxybutyric Acid 합성시 배양온도와 영양분의 영향)

  • 이상엽
    • Microbiology and Biotechnology Letters
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    • v.22 no.6
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    • pp.614-620
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    • 1994
  • The effects of growth temperature and nutritional components on the synthesis of poly-3-hydroxybutyric acid, PHB, by filamentation-suppressed recombinant Escherichia coli XL1-Blue (pSYL107) were studied. After culturing XL1-Blue(pSYL107) for 48 hours in complex medium at 30$\circ$C, 7Al g/l of PHB could be obtained with the PHB content and PHB yield of 82% and 0.371 g PHB/g glucose, respectively. Lower concentration of PHB(3.2 g/l) was obtained when cultu- red at 37$\circ$C, which seemed to be due to the instability of this strain having amplified FtsZ activity. The PHB concentration of 3.75 g/l was obtained after culturing 60 hours in R medium supplemen- ted with 20 g/l glucose at 30$\circ$C, which was more than twice higher than that obtained with XL1-Blue(pSYL105). This suggested that the enhancement of PHB synthesis by suppressing filamenta- tion was more significant in a defined medium than complex medium. PHB synthesis could be further enhanced by supplementing a small amount of various complex nitrogen sources. When 5 g/l of beef extract was added to a defined medium, PHB concentration, PHB content, and PHB yield obtained after 60 hours of cultivation at 30$\circ$C were 7.46 g/l, 86%, and 0.375 g PHB/g glucose,respectively.

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Construction of the Recombinant phbCAB Operon of Alcaligenes eutvtrphus for Accumulation of Poly-$\beta$-hydroxybu tyric Acid in Escherichia coli (Alcaligenes eutrophus phbCAB Operon의 재조합과 Poly-$\beta$-hydroxybutyric Aicd의 대장균내 축적)

  • 김경태;박진서;이용현;허태린;박해철
    • Microbiology and Biotechnology Letters
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    • v.21 no.3
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    • pp.221-228
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    • 1993
  • In order to achieve poly-beta-hydroxybutyric acid (PHB) production using recombinant DNA in various host bacterial cells, the isolation of genes for PHB biosynthesis was attempted. As a result, a 5.2kb DNA fragment containing phbCAB operon of Alcaligenes eutrophus was isolated by colony hybridization using synthetic oligodeoxyribonucleotides as probes. The constructed recmbinant plasmid pSK(+)-phbCAB operon was transferred to Escherichia coli, and the obtained transformant accumulated considerable amount of PHB.

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Effects of Culture Conditions on the Molecular Weight of Poly-hydroxybutyric acid (PH B) Produced by Alcaligenes sp. K-912

  • Yeom, Sung-Ho;Yoo, Young-Je
    • Journal of Microbiology and Biotechnology
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    • v.4 no.3
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    • pp.210-214
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    • 1994
  • The molecular weight of poly-hydroxybutyric acid (PHB) produced by Alcaligenes sp. K-912 is an important parameter characterizing the physical properties of the polymer. The effects of temperature and the levels of glucose, ammonium, phosphate and amino acids on the molecular weight of PHB were investigated. Molecular weight of PHB by temperature varied in the range of 380,000 to 550,000, 400,000 to 600,000 by glucose, 300,000 to 380,000 by phosphate, 400,000 to 1,000,000 by amino acids, respectively under the experimental conditions.

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Effects of Chitosan Addition on Physical Properties and Crystallization of Poly(3-hydroxybutyric acid) Film (Chitosan 첨가가 Poly(3-hydroxybutyric acid) 필름의 물리적 특성 및 결정구조에 미치는 영향)

  • 김미라;구진경
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.31 no.3
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    • pp.475-481
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    • 2002
  • Blend films of poly(3-hydroxybutyric acid) (PHB) with chitosan were prepared, and their Physical properties and crystallization were investigated. The degree of crystallinity of PHB/chitosan films by X-ray diffraction decreased with increasing chitosan concentration. In the fourier-transformed infrared spectra, carbonyl peak of PHB became lower with increasing the amount of chitosan. The addition of chitosan to PHB film decreased thermal stability and crystallinity of the blend films. The granular sizes of the films were reduced with the addition of chitosan to the film in the microstructural observation by a scanning electron microscope. Mechanical properties, including tensile strength and percent elongation, of the blend films increased with increasing chitosan ratio in the films. For color of the films, L and b values generally decreased with increasing chitosan ratio, but transparency of the films increased.

Gas and Lipid Permeabilities and Biodegradability of Poly(3-Hydroxybutyric Acid)/Chitosan Blend Film (Poly(3-Hydroxybutyric Acid)와 Chitosan 블렌드 필름의 기체 투과도, 유지 투과도 및 생분해도)

  • 김미라
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.33 no.7
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    • pp.1224-1229
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    • 2004
  • The blend films of poly(3-hydroxybutyric acid) (PHB) with chitosan were prepared and water vapor transmission rate, oxygen permeability and lipid permeability of the PHB/chitosan films were measured. Additionally, the biodegradability of the PHB/chitosan films was also evaluated. Water vapor transmission rate and oxygen permeability of the films decreased by the addition of chitosan. The addition of polyethylene glycol (PEG, plasticizer), however, increased the water vapor transmission rate and oxygen permeability of the films. In the evaluation of lipid permeability, all the films except PHB (the film made of only PHB) and PHB-P (the film made of PHB and PEG) did not permeate beef tallow for 24 hours. The consumed oxygen for PHB/chitosan films during incubation was greater than that for the control on the biodegradability determination of the films, which implies that PHB/chitosan films were degraded by the microorganisms. The higher PHB ratio of the films was, the faster biodegradation of the films occurred.

Production of $poly-{\beta}-hydroxybutyric$ acid by methanol assimilating bacterium, Pseudomonas sp. ILS-003 (Methanol 자화성 세균 Pseudomonas sp. ILS-003에 의한 $poly-{\beta}-hydroxybutyric$ acid의 생산)

  • Lee, Il-Seok;Bang, Won-Gi
    • Applied Biological Chemistry
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    • v.34 no.3
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    • pp.273-278
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    • 1991
  • Methanol assimilating bacterium, Pseudomonas sp. ILS-003 was used to investigate the optimum conditions for the production of $poly-{\beta}-hydroxybutyric$ acid from methanol. For PHB production, the optimum initial pH was 6.4 and the optimum temperature was $30^{\circ}C$. Also the optimum methanol concentration was found to be 1.0%(v/v). In the PHB production, $(NH_4)_2SO_4$ was the most effective nitrogen source and the optimum concentration was 0.8 g/l, which was eqivalent to 17.4 in C/N ratio. Also, deficiency of the 2 valence metal ions in the medium had stimulating effect on PHB accumulation. Under the optimum substrate concentration, successive feeding of 0.25%(v/v) methanol was the most effective on PHB production. Under the optimum conditions, 1.94 g/l of PHB and 2.78 g/l of dry biomass were produced in 96 hours, and the yield was 69.8%(w/w).

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Effect of Cosubstrate on tile Production of Poly(3-Hydroxybutyric-Co-3-Hydroxyvaleric) Acid from Glucose by Pseudomonas sp, HJ (Pseudomonas sp. HJ에 의한 포도당으로부터 Poly(3-Hydroxybutyric-Co-3-Hydroxyvaleric) Acid의 생합성에 대한 보조기질의 영향)

  • 손홍주;고명선이상준
    • KSBB Journal
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    • v.11 no.5
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    • pp.586-592
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    • 1996
  • Poly(3-hydroxybutyric-co-3-hydroxyvaleric) acid(PHB/HV) copolymer synthesis by Pseudomonas sp. HJ from glucose and cosubstrate was investigated. Taxonomic analysis suggested that Pseudomonas sp. HJ was best marched to Pseudomonas picketti having 78.8% similarity. Pseudomonas sp. HJ produced PHB/HV copolymer containing 60.8 mol% HV and 44.9 mol% HV when supplied with hexadecane and propionic acid as a cosubstrate, respectively. The HV composition in PHB/HV copolymer was controlled by varying the concentration of hexadecane and propionic acid. Propionic acid added after 24 hours of incubation was incorporated as the HV monomer in the PHB/HV copolymer up to 49.6 mol%.

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Accumulation of Poly-$\beta$-Hydroxybutyrie Acid by Alcaligenes sp. (Alcaligenes sp.에 의한 Poly-$\beta$-Hydroxybutyric Acid의 축적)

  • 임명순;손홍주;박수민;이종근;이상준
    • Microbiology and Biotechnology Letters
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    • v.20 no.4
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    • pp.363-370
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    • 1992
  • Microorganisms capable of accumulating poly-p-hydroxybutyric acid(PHB) were isolated from soil by enrichment culture technique. Among them, the strain designated as FL-027 had high PHB productivity and was identified as Alcaligenes. The optimal medium composition for cell growth was 8.0 $g/\ell$ of fructose and 3.0 $g/\ell$ of $(NH_4)_2S0_4$, equivalent to C/N ratio 5.04 at pH 7.0 and $30^{\circ}C$. To investigate the optimal conditions for the PHB accumulation, we divided the process into two stages; the first stage for the growth of the cell in nutrient-rich medium and the second stage for the PHB accumulation in nutrient-deficiency medium. The optimal conditions for PHB accumulation were 8.0 $g/\ell$ of fructose and 0.25 $g/\ell$ of $(NH_4)_2S0_4$, equivalent to C/N ratio 60 at pH 6.5 and $30^{\circ}C$. PHB accumulation was stimulated by deficiency of nutrients such as $NH_4^+$, $Ca^{2+}$, $SO_4^{2+}$ in medium. Among them. $NH_4^+$ deficiency was chosen because of its effectiveness. We found the inhibition of cell growth by fructose in batch culture. In order to keep the fructose concentration at an optimal level, intermittent feeding fed-batch culture was employed, and the cell concentration as high as 10.83 $g/\ell$ whose PHB content was responsible for 43% of the dry cell weight. The purified PHB was identified as homopolymer of 3-hydroxybutyric acid by using IR and $^1H-NMR$.

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Production of Enantiomerically Pure [R]-3-Hydroxybutyric acid by Metabolically Engineered Escherichia coli with Inducible System (Inducible System을 이용한 재조합 대장균으로부터 광학적으로 순수한 [R]-3-Hydroxybutyric acid 생산)

  • 이영;최종일;이상엽
    • KSBB Journal
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    • v.19 no.4
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    • pp.327-330
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    • 2004
  • An inducible expression system of poly[(R)-3-hydroxybutyrate] (PHB) depolymerization was established in metabolically engineered Escherichia coli with the PHB biosynthesis genes. The Ralstonia eutropha PHB depolymerase gene was cloned in a vector system containing the PHB biosynthesis genes and expressed under inducible promoter. Recombinant E. coli harboring the PHB biosynthesis genes and depolymerase gene was first cultured for the accumulation of PHB, and then the depolymerase was expressed resulting in the degradation of accumulated PHB into (R)-3-hydroxybutyric acid (R3HB). R3HB could be produced with the concentration of 7.6 g/L in flask culture. Two different PHB biosynthesis genes from Alcaligenes latus and R. eutropha were compared for the production of R3HB. This strategy can be used for the production of enantiomerically pure (R)-hydroxycarboxylic acids with high concentration.