• 폴리머
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• 제31권3호
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• pp.228-232
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• 2007

본 연구에서는 의료용 흡수성 재료 및 환경적합성 재료의 개발을 목적으로 생체흡수성의 poly(glycolic acid)(PGA)를 심선(芯線)에 제작하고, 환경분해성의 poly(butylene succinate-co-L-lactate)(PBSL) 및 poly [(R)-3-hydroxybutylate] (PHB)를 외층(外層)에 지닌 복합섬유를 제작하여, PGA의 가수분해에 의해 발생되는 glycolic acid에 의한 PBSL 및 PHB의 가수분해성의 향상을 도모하고자 하였다. 그 결과 PBSL/PGA 복합섬유에 대한 연신은 $65^{\circ}C$에서 실시함에 의해 결정배향이 잘 배열된 섬유를 얻었다. 그러나 PHB/PGA 복합섬유는 $50^{\circ}C$에서는 결정배향이 양호한 섬유를 얻을 수 없었기 때문에 $50^{\circ}C$ 이상의 온도에서 연신을 실시해야 양호한 복합섬유를 얻을 수 있음을 알았다. 또한 in-line 연신에서는 섬유표면에 요철이 발생되기 때문에 on-line 연신을 실시하는 것이 매끄러운 표면을 얻을 수 있음을 알았다.

• KSBB Journal
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• 제13권2호
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• pp.187-194
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• 1998

For mass production of polyhydroxyalkanoates (PHA), high cell density cultures of Alcaligenes eutrophus by fed-batch culture under phosphate-limitation condition has been investigated. PHA accumulation by the regulation by the regulation of initial phosphate concentration could be automatically induced, and high density cell culture above 200 g/L also could be successfully produced. The production of Poly-$\beta$-hydroxybutyrate (PHB) and dry cell weight increased with increasing the initial phosphate concentration. When the initial concentrations of phosphate were in the ranges of 1.5~4.5 g-PO$_4$/L, PHB and dry cell weight obtained were 83~266 g/L and 61~216 g/L, respectively, and PHB productivity was in the ranges of 1.35~3.10 g/L.h. When a mixture of glucose and propionic acid is used as carbon sources, poly(3-hydroxybutyrate-co-poly-3-hydroxyvalerate), P(3HB-co-3HV), could be also successfully produced under phosphate limitation condition. When the mole ratio of propionic acid to glucose in the feeding solution is 0.22, a final dry cell weight of 150 g/L and a P(3-HB-co-3HV) of 90 g/L were produced. Morphological changes and size distribution of PHB granules synthesized in A. eutrophus under phosphate-limitation condition are determined by TEM during the course of fed-batch. Mean granule diameters of PHB produced are in the range of 0.36~0.39 $\mu$m, and mean cell size was elongated from 0.54~0.59 $\mu$m$\times$ 1.3~1.5 $\mu$m to 0.83~0.89 $\mu$m $\times$2.0~2.3 $\mu$m. Phosphate concentration in media did not affect size distribution of PHB granule and cell.

• KSBB Journal
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• 제10권5호
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• pp.533-539
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• 1995

재조합 대장균에 의해 생합성된 PHB를 분리정제하기 위하여 박테리오파아지의 세포파괴작용을 이용하는 방법의 가능성에 대해 알아 보았다. 먼저, $cI_{857}$ 유전자를 지난 박테리오파아지 A를 대장균에 감염시킨 후 lysogen, XLl-Blue($\lambda$HL1)를 선별하고, 이 균주에 PHA 생합성 플라스미드를 도입시켜 원하는 균주인 XLI-Blue($\lambda$HL1, pSYLl05)를 만들였다. 숙주인 XLl-Blue, 열적유도에 의해 세포파괴가 가능한 XLl-Blue($\lambda$HL1), 그리고 세포파괴와 PHB 생합성이 모두 가능한 XLl-Blue(AHL1, pSYL105) 에 대하여 여러 가지 조건에서의 실험결과를 비교.검토하였다. XLI-Blue($\lambda$IL1, pSYLl05)의 경우 대수기에서는 열적유도만으로 세포파괴를 효과적으로 야기할 수 있었으나 PHB가 축적되는 정지기에서는 열척유도만으로 세포파괴를 일으킬 수 없었다. 세포 파괴를 보다 용이하게 하기 위하여 열적유도 빛 2% (v/v)의 chloroform을 사용하는 화학적용균을 병행 하였는데, 이 경우 세포파괴가 효과적으로 일어남을 관찰할 수 있었다.

• 한국환경과학회지
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• 제31권7호
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• pp.609-616
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• 2022

In this study, the effect of different reaction times for thermal-alkaline pretreatment on the solubilization and biogasification of polyhydroxybutyrate (PHB) were evaluated. Thermal-alkaline pretreatment tests were performed at 73 ℃ and pH 13 at 0-120 h reaction times. The mesophilic anaerobic batch tests were performed with untreated and pretreated PHB samples. The increase in the pretreatment reaction time results in a 52.8-98.8% increase of the abiotic solubilization efficiency of the PHB samples. The reaction time required to achieve solubilization efficiencies of 50%, 90%, and 95% were 10.5, 52.0, and 89.6 h, respectively. The biogasification of the untreated PHB samples achieved a specific methane production rate of 3.6 mL CH₄/g VSS/d and require 101.3 d for complete biogasification. The thermal-alkaline pretreatment significantly improved specific methane production rate (10.2-16.0 time increase), lag time (shortened by 76-81%), and time for complete biogasification (shortened by 21-83%) for the biogasification of the PHB samples when compared to those of the untreated PHB samples. The improvement was higher as the reaction time of the thermal-alkaline pretreatment increased. The findings of this study could be used as a valuable reference for the optimization of the biogasification process in the treatment of PHB wastes.

• 한국고분자학회지:고분자과학과기술
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• 제5권1호
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• pp.5-12
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• 1994

• 공업화학
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• 제3권3호
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• pp.371-376
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• 1992

• 한국미생물·생명공학회지
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• 제24권3호
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• pp.344-351
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• 1996

Microorganisms growing alcoholic distillery wastes were isolated from soil. Of them, the selected strain EL-9 had a capability of accumulating poly-$\beta$-hydroxybutyrate (PHB) when grown in alcoholic distillery wastes. The strain EL-9 was identified as a genus Actinobacillus based on the morphological, cultural, and biochemical characteristics. The strain EL-9 was named temporarily as Actino- bacillus sp. EL-9. The optimal temperature and pH for cell growth of Actinobacillus sp. EL-9 were 30$\circ$C and 7.0, respectively. The optimal medium compositions for cell growth comprised glucose 2%, NH$_{4}$NO$_{3}$ 0.15%, Na$_{2}$HP0$_{4}$-12H$_{2}$O 0.25%, KH$_{2}$PO$_{4}$ 0.25%, MgSO$_{4}$4-7H$_{2}$O 0.15%, FeSO$_{4}$-7H$_{2}$O 0.005%, CaCl$_{2}$-2H$_{2}$O 0.003% and trace element solution 5m/l. To investigate the optimal conditions for PHB production, two-stage culture technique was used. The result showed that the optimal conditions for PHB production are identical those for cell growth. When propionic acid was added as a cosubstrate, PHB/HV copolymer was produced.

• 한국환경과학회지
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• 제27권9호
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• pp.753-762
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• 2018

The present study set out to investigate the adsorption of Cd(II) ions in an aqueous solution by using Peanut Husk Biochar (PHB). An FT-IR analysis revealed that the PHB contained carboxylic and carbonyl groups, O-H carboxylic acids, and bonded-OH groups, such that it could easily adsorb heavy metals. The adsorption of Cd(II) using PHB proved to be a better fit to the Langmuir isotherm than to the Freundlich isotherm. The maximum Langmuir adsorption capacity was 33.89 mg/g for Cd(II). The negative value of ${\Delta}G^o$ confirm that the process whereby Cd(II) is adsorbed onto PHB is feasible and spontaneous in nature. In addition, the value of ${\Delta}G^o$ increase with the temperature, suggesting that a lower temperature is more favorable to the adsorption process. The negative value of ${\Delta}H^o$ indicates that the adsorption phenomenon is exothermic while the negative value of ${\Delta}S^o$ suggests that the process is enthalpy-driven. As an alternative to commercial activated carbon, PHB could be used as a low-cost and environmentally friendly adsorbent for removing Cd(II) from aqueous solutions.

• 생명과학회지
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• 제8권5호
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• pp.526-531
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• 1998

In this study, the composition and characteristics of poly-$\beta$-hydroxybutyrate (PHB) biosynthesized by Actinobacillus sp. EL-9 are investigated. PHB produced by Actinobacillus sp. EL-9 was identified as the homopolymer of 3-hydroxy-butyric acid (PHB) by infrared spectroscopy and nuclear magnetic resonance spectroscopy analysis. The melting tem-perature (T$_{m}$), and crystallization temperature(T$_{c}$) of PHB was 169.7$^{\circ}C$ and 69.13$^{\circ}C$, respectively. The viscosity on he basis of Brookfield viscometer was 6.01 ㎗/g. The viscosity-average molecular weight estimated by Mark-Ho-wink-Sakurada equation was 1.08$\times$10$^{6}$ ($\pm$3,000).00).

• Journal of Microbiology
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• 제40권2호
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• pp.129-133
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• 2002

The fungus, Emericellopsis minima W2, capable of degrading poly(3-hydroxybutyrate) (PHB) was isolated from a waste water sample. Production of the PHB depolymerase from E. minima W2 (PhaZ/ sub Emi/) was significantly repressed in the presence of glucose. PhaZ/ sub Emi/ was purified by column chromatography on Octyl-Sepharose CL-4B and Sephadex G-100. The molecular mass of the PhaZ/ sub Emi/), which consisted of a single polypeptide chain, was estimated to be 48.0 kDa by SDS-PAGE and its pI vague was 4.4. The maximum activity of the PhaZ/ sub Emi/ was observed at pH 9.0 and 55$\^{C}$. It was significantly inactivated by 1mM dithiothreitol, 2mM diisopropyl fluorphosphate, 0.1mM Tween 80, and 0.1 mM Triton X-l00, but insensitive to phenylmethylsulfonyl fluoride and N-ethylmaleimide. The PhaZ/ sub Emi/ efficiently hydrolyzed PHB and its copolyester with 30 mol% 3-hydroxyvalerate, but did not act on poly(3-hydroxyoctanoate). It also hydrolyzed p-nitrophenylacetate and p-nitrophenylbutyrate but hardly affected the longer-chain forms. The main hydrolysis product of PHB was identified as a dimer of 3-hydroxybutyrate.