• Biotechnology and Bioprocess Engineering:BBE
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• 제10권6호
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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.

• 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.

• 폴리머
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• 제32권3호
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• pp.284-289
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• 2008

Poly(n-butylmethacrylate)(PBMA)와 poly(3-hydroxybutyrate-co-4-hydroxybutyrate)(PHA)가 혈관 협착 방지를 위한 국소 약물 요법시 유용한 고분자인지 검정하였다. 10% paclitaxel 함유 필름으로부터 방출되는 paclitaxel은 초기 1주간은 빠르게, 30일까지는 중증도로, 이후는 천천히 방출되었다. Paclitaxel 함유 필름들은 풍선 손상을 가한 쥐 경동맥의 신생내막 증식을 억제하였다(PBMA vs control : $0.03{\pm}0.02$ vs $0.10{\pm}0.01\;mm^2$, p<0.05; PHA vs control: $0.04{\pm}0.03$ vs $0.09{\pm}0.01\;mm^2$, p<0.05). PBMA와 PHA는 혈관 협착 방지를 위한 약물 전달 고분자로 유용할 것으로 사료된다. 고분자 필름은 혈관 외벽에 장착이 용이한 경우 사용될 수 있다. 또한, 이 고분자들은 약물 방출 스텐트 개발시 이용될 수 있다.

• 한국염색가공학회지
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• 제30권2호
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• pp.130-140
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• 2018

In the bio-synthesis of poly(3-hydroxybutyrate)(PHB), which is a kind of poly(3-hydroxyalkanoate)(PHA), aimed to control the low molecular weight of PHB and obtain a telechelic PHB. As a result of incubation of R. eutropha at $30^{\circ}C$ with ethylene glycol added as a chain transfer agent, PHB content on the dry cell weight increased up to 24h, however, it decreased after that, and the molecular weight of PHB increased from 9h to 12h, and then, decreased up to 72h. The decrease of the content and the molecular weight of PHB indicates that PHB was decomposed as an energy source in bacterial cells and was incorporated into metabolic pathways. $^1H-NMR$ of the obtained PHB after incubation for 72h was measured to determine the terminal groups of the PHB during incubation. As the results of $^1H-NMR$ measurement, the peaks derived from ethylene glycol in both terminals of PHB were observed. Which indicate that the terminal reaction was caused by the addition of ethylene glycol, and that telechelic PHB having hydroxyl group at the both terminals where molecular weight was controlled was successfully synthesized.

• 한국균학회지
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• 제23권4호통권75호
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• pp.348-353
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• 1995

Poly (3-hydroxybutyrate)(PHB) 의 Penicillium pinophilum에 의한 생분해성을 변형 Sturm Test 법으로 조사하였다. 활성오니를 사용한 경우보다 PHB의 생분해성이 비교적 재현성있게 측정되었으며 PHB의 생분해를 가장 빠르게 진행시키는 최적 포자 접균량은 1 %(v/v)이었다. 생분해 속도는 시료의 표면적에 따라 증가하였으나 비례적으로 상승하지 않아 분해가 시료의 표면 뿐만 아니라 내부에서도 진행됨을 나타내었다. 반응 배지내의 질소원 함량에 따라 PHB의 생분해 속도는 증가하다가 점근값을 보여 질소원이 depolymerase 효소의 합성에 필요한 원소임을 보였다.

• 접착 및 계면
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• 제16권3호
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• pp.108-115
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• 2015

본 연구는 poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/그래핀 복합체의 제조 및 특성에 관한 연구이다. 투입하는 그래핀의 함량에 따른 복합체의 전기적 물성, 소수성, 및 열적 성질에 미치는 영향에 대해 연구하였다. 표면주사전자현미경 연구결과 PHBV 고분자 matrix에 판상의 그래핀이 고르게 잘 분산되었음을 확인하였다. X-선 회절 연구와 시차열량주사계 분석을 통하여 그래핀을 첨가할수록 PHBV의 결정도를 증가시켰고, 투입하는 그래핀의 함량이 증가할수록 복합체의 열적 안정성, 소수성 및 전기전도도 등이 증가하는 것으로 나타났다.

• 폴리머
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• 제29권1호
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• pp.54-58
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• 2005

미생물 합성 poly[(R)3-hydroxybutyrate]](P(3HB))의 알칼리 및 효소 분해거동을 단결정과 Langmuir 단분자막을 모델시스템으로 하여 연구하였다. 단결정의 초기효소 및 알칼리 분해거동은 단결정의 장축에 대해 수직방향(b축)으로 분해가 일어났고 용융점 이하의 온도에서 열처리 또한 단결정의 b축을 따라 봉우리 형태의 형태학적 변화를 관찰하였다. 이러한 결과는 라멜라 단결정은 b축을 따라 불규칙한 영역을 가지고 있음을 의미하고 효소분해가 불규칙한 영역에서 선호적으로 일어난다고 설명할 수 있다. 한편, P(3HB), 단분자막의 효소 및 알칼리 분해경향은 분해매체와 표면압력에 크게 의존하였다. 알칼리 분해의 경우 낮은 표면압력에서도 분해를 나타내는 반면 효소 분해는 높은 표면 압력 하에서 분해거동을 나타내었다. 이러한 현상은 분자수준의 크기인 알칼리 분해매체는 P(3HB) 단분자막과 좁은 접촉면적(낮은 표면압력)에서도 활성을 보이는 반면 크기가 큰 분해효소는 보다 큰 활성 접촉면적(높은 표면압력)을 필요로 하는 것으로 판단된다.

• Journal of Microbiology and Biotechnology
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• 제9권6호
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• pp.722-725
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• 1999

Filamentation-suppressed recombinant Escherichia coli strain harboring the Alcaligenes latus polyhydroxyalkanoate (PHA) biosynthesis genes and the E. coli ftsZ gene was constructed and cultivated for the production of poly(3-hydroxybutyrate) [P(3HB)] with high concentration and high content. By the pH-stat fed-batch culture of this recombinant E. coli strain XL1-Blue(pJC5), the final cell concentration and P(3HB) concentration obtained in 44.25h were 172.2g cell dry weight/l and 141.9g P(3HB)/l, respectively, resulting in productivity of 3.21g P(3HB)/l-h. More importantly, the P(3HB) content obtained was 82.4 wt %, which was significantly higher than that obtained with the recombinant E. coli harboring only the PHA biosynthesis genes.

• KSBB Journal
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• 제13권5호
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• pp.615-620
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• 1998

The readily fermentable carbon sources in swine were acetic acid, propionic acid and butyric acid at the average concentrations of 7.2 g/L, 2.2 g/L and 2.7 g/L, respectively. The swine waste also contained excess nitrogen and other mineral sources. In shake flask experiments, the optimal range of cell growth for Azotobacter vinelandii UWD were 1.0∼3.5 g/L of acetic acid, 0.7∼2.0 g/L of propionic acid and 0.5∼2.0 g/L of butyric acid. A mixture of these three acids simulating two times diluted swine waste supported the best cell growth but the amount of carbon sources was limited. In shake flask and fermentor experiments, an addition of 30 g/L of glucose increased the final cell dry weight 8 times while the final poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) concentration increased 86 times compared with using acid mixture only. A. vinelandii UWD preferred organic acids in the sequence of acetic acid, propionic acid, butyric acid, and valeric acid.

• 한국환경과학회지
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• 제26권1호
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• pp.1-10
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• 2017

In this study, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/graphene oxide (GO) nanocomposite films containing various content of GO were prepared using solution casting method. The effect of GO content on Young's modulus and dispersion of GO in PHBV matrix was investigated. Also, the thermomechanical properties, oxygen transmission rates and hydrolytic degradation of PHBV/GO nanocomposite films were studied. The addition of GO into PHBV improves the Young's modulus and decreases thermal expansion coefficient. The improvement can be mainly attributed to good dispersion of GO and interfacial interactions between PHBV and GO. Furthermore, PHBV/GO nanocomposite films show good oxygen barrier properties. PHBV/GO nanocomposites show lower hydrolytic degradation rates with increasing content of GO.