• KSBB Journal
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• 제18권2호
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• pp.107-110
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• 2003

스텐트 재질인 stainless steel 표면에 모델 약물인 rose bengal을 포함한 생분해성 고분자 PLGA, PHB, MCL-PHA를 코팅하여 약물방출 특성을 조사하였다. PLGA의 농도가 낮을수록, rose bengal의 농도가 높을수록, dip-coating 시간이 길수록 약물방출이 증가하였으며, PHB > PLGA > MCL-PHA의 순서로 약물이 빨리 방출되었다. 이는 생분해성 고분자의 농도 및 종류, 약물의 농도, dip-coating 시간 등을 변화시켜 약물방출을 조절할 수 있음을 나타낸다.

• Journal of Microbiology and Biotechnology
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• 제4권2호
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• pp.126-133
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• 1994

A Pseudomonas putida strain able to accumulate high amount of polyesters of medium-chain-length 3-hydroxyalkanoic acids ($PHA_{MCL)$) was isolated from soil in a landfill site using an enrichment technique. Culture condition of the isolated strain for polyester production in a one-step culture was optimized in a mineral-salts medium against pH and concentrations of ammonium sulfate, carbon source(e.g., octanoate), and phosphate. The optimal values for maximal cell growth and PHA accumulation were: pH; 7$\sim$8, $(NH_4)_2SO_4$; 8 mM, octanoate; 40 mM. The optimum temperature was in the range of $20\sim30^{\circ}C$, which was rather broader than in other bacteria. Cell growth was strongly inhibited by the phosphate limitation to less than 1 mM. An increase of phosphate concentration above 1 mM showed little effect on cell growth and polyester accumulation. When the strain was grown on octanoate under this optimized condition it produced 3.4 g dry biomass per liter and yielded 1.7 g PHA per liter amounting to 53 wt% of dry cells. The monomer units composing the polyester synthesized from octanoate were 3-hydroxyoctanoate (3HO), 3-hydroxycaproate (3HC), and 3-hydroxybutyrate (3HB) (85:13:2, mole ratio). Other low linear $C_3\simC_{10}$ monocarboxylic acids were also tested for polyester production.

• KSBB Journal
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• 제19권4호
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• pp.331-334
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• 2004

재조합 E. coli를 이용한 MCL-PHA의 생산에서 fatty acid pathway로부터 PHA 생합성 전구체 물질들이 만들어진다는 사실과 함께 이에 관여하는 enzymes이 밝혀지고 있다. 본 논문에서는 protein homology search로부터 탐색된 paaG와 ydbU genes의 PHA 생합성에서의 역할을 확인하기 위하여 paaG와 ydbU gene이 각각 knock-out된 mutant E. coli strains 를 제작하였다. 제작된 mutant E. coli들은 모균주들보다 낮은 PHA 농도와 함량을 가졌으며, 이러한 결과들로부터 paaG와 ydbU는 fatty acid pathway에서 PHA synthesis의 전구체 물질들을 공급한다는 사실을 확인하였다. 또한, 새로운 FadB homologous enzyme YgfG를 탐색하였으며, ygfG gene이 overexpression된 균주와 ygfG mutant를 제작하여 PHA 합성을 실험한 결과 ygfG도 paaG와 ydbU와 유사한 역할을 한다는 사실을 밝혔다. 이러한 연구결과들은 E. coli에서의 MCL-PHA 단량체들의 합성 경로를 확인하여 효과적인 PHA 생산 균주를 제작할 수 있게 할 것이다.

• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.1120-1124
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• 2005

Pseudomonas putida KCTC 1639 was newly identified as a potential producer of biodegradable medium chain length polyhydroxyalkanoates. It exhibited a carbon assimilation pattern quite different from other known P. putida strains, but a more similar pattern with P. oleovorans, which assimilates the carbon sources mainly through ${\beta}$-oxidation rather than the fatty acid biosynthesis pathway. The PHA synthesis gene cluster from P. putida KCTC1639 was composed of two gene loci; the PHA synthase gene locus and granule-associated gene locus, which were cloned and deposited in the GenBank under accession numbers AY286491 and AY750858 as a new nucleotide sequence, respectively. The molecular structure and amino acid homology of the new gene cluster were compared with those from Pseudomonas species, including other P. putida strains and P. oleovorans, and a higher than $90\%$ homology was observed.

• 한국미생물·생명공학회지
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• 제32권2호
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• pp.123-127
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• 2004

토양으로부터 oleic acid 를 탄소원으로 이용하여 MCL-PHA의 생산능이 우수한 균주를 분리하여 Pseudomonas sp. MBEL21이라 명명하였다. Pseudomonas sp. MBEL21의 PHA함량을 증가시키기 위하여 여러 가지 필수 영양분의 제한 조건에서 배양한 결과, 인산이 제한된 조건에서 가장 높은 함량의 PHA를 축적하였다. 고농도의 MCL-PHA생산을 위한 Pseudomonas sp. MBEL21의 유가식 배양 전략을 개발하여 28.1 wt％의 함량으로 23 g/L. MCL-PHA를 생산하였다. 또한, 분리된 Pseudomonas sp. MBEL21을 olive oil을 탄소원으로 이용하여 배양한 결과 9.3 wt％의 PHA가 축적되어졌으며, MCL-hydroxyalkanoate와 함께 3-hyoxy-butyrate 의 단량체들로 이루어진 PHA가 확인되어졌다. 이러한 결과들은 분리된 신규 Pseudomonas sp. MBEL21이 저가의 olive oil로부터 생분해성 탄성체의 응용분야를 갖는 MCL-PHA를 효율적으로 생산할 수 있다는 것을 보여준다.

• Journal of Microbiology and Biotechnology
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• 제27권5호
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• pp.990-994
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• 2017

Polyhydroxyalkanoates (PHAs) are biodegradable plastics produced by bacteria, but their use in diverse applications is prohibited by high production costs. To reduce these costs, the conversion by Pseudomonas strains of PHAs from crude sludge palm oil (SPO) as an inexpensive renewable raw material was tested. Pseudomonas putida S12 was found to produce the highest yield (~41%) of elastomeric medium-chain-length (MCL)-PHAs from SPO. The MCL-PHA characteristics were analyzed by gas-chromatography/mass spectrometry, gel permeation chromatography, and differential scanning calorimetry. These findings may contribute to more widespread use of PHAs by reducing PHA production costs.

• Journal of Microbiology and Biotechnology
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• 제22권3호
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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.