• 제목/요약/키워드: continuous cultures

검색결과 143건 처리시간 0.027초

Metabolic Pathways of Hydrogen Production in Fermentative Acidogenic Microflora

  • Zhang, Liguo;Li, Jianzheng;Ban, Qiaoying;He, Junguo;Jha, Ajay Kumar
    • Journal of Microbiology and Biotechnology
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    • 제22권5호
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    • pp.668-673
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    • 2012
  • Biohydrogen production from organic wastewater by anaerobically activated sludge fermentation has already been extensively investigated, and it is known that hydrogen can be produced by glucose fermentation through three metabolic pathways, including the oxidative decarboxylation of pyruvic acid to acetyl-CoA, oxidation of NADH to $NAD^+$, and acetogenesis by hydrogen-producing acetogens. However, the exact or dominant pathways of hydrogen production in the anaerobically activated sludge fermentation process have not yet been identified. Thus, a continuous stirred-tank reactor (CSTR) was introduced and a specifically acclimated acidogenic fermentative microflora obtained under certain operation conditions. The hydrogen production activity and potential hydrogen-producing pathways in the acidogenic fermentative microflora were then investigated using batch cultures in Erlenmeyer flasks with a working volume of 500 ml. Based on an initial glucose concentration of 10 g/l, pH 6.0, and a biomass of 1.01 g/l of a mixed liquid volatile suspended solid (MLVSS), 247.7 ml of hydrogen was obtained after a 68 h cultivation period at $35{\pm}1^{\circ}C$. Further tests indicated that 69% of the hydrogen was produced from the oxidative decarboxylation of pyruvic acid, whereas the remaining 31% was from the oxidation of NADH to $NAD^+$. There were no hydrogen-producing acetogens or they were unable to work effectively in the anaerobically activated sludge with a hydraulic retention time (HRT) of less than 8 h.

제브라피쉬(Danio rerio) 배아로부터 동형세포주 확립 (Establishment and Characterization of Clonal Cell Lines from Zebrafish, Danio rerio)

  • 이기영
    • 한국어류학회지
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    • 제20권1호
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    • pp.1-6
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    • 2008
  • 제브라피쉬 배아로부터 확보한 세포주로부터 외부형태와 세포 크기에 따라 3종류의 동형세포주를 확립하였다. 활발하게 증식하는 안정된 세포주 및 이들로부터 확립된 동형세포주의 세포특성은 변하지 않고 지속적으로 유지되었으며, 안정된 세포주로부터 총 18개의 콜로니를 확보하여 배양한 다음 3종류의 동형세포주를 선별하여 세포 특성을 분석하였다. 대부분의 동형세포주는 약 80% 정도 정상적인 염색체(2N=50)를 가지고 있었으며 FACs 분석과 일치하였다. 배아로부터 확립된 동형세포주에 항체테스트 결과, vimentin에서 양성을 보이는 결과로 볼 때 확립된 세포주는 분화된 섬유세포임이 확인되었다. 이러한 결과는, 확립된 동형세포주를 이용한 유전자조작과 어류복제에의 활용도를 높일 수 있음을 시사한다.

도시환경과 건물 재생을 위한 파노라마 이미지 공간구성 방법 (A Study on the Panoramic Perception for Restoring of Urban Environment and Architecture)

  • 전수경;남경숙
    • 한국실내디자인학회논문집
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    • 제23권1호
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    • pp.78-87
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    • 2014
  • The purpose of this paper is to analyze the relationship between panoramic perception and space organization for restoration of urban environment and architecture. Panorama is a collective visual catalogue composed by series of perspective images. It is a product from continuous movements of viewer by defamilarizing real image and structuring order between city and building. Through understanding the panoramic image, the viewer is able to achieve the total image of the city. For example, achieving visual perception of the city by employing the panoramic view from different historical backgrounds and cultures, Berlin developed its urban characteristic by rebuilding panoramic view as an aesthetic device. First, this paper mention theory of panorama as an aesthetic device for shaping the city from the building. Second, this paper analyze the relationships between characteristics of panorama and historical contexts for why those panoramic views are valuable by mentioning the Altes Museum, the Berlin National Gallery, Museum of Modern Literature, and Folkwang Museum of panoramic view. In conclusion, this paper argues that visual perception such as panoramic view is the valuable device for organizing the image of the city's own identity. Constructing vision of each city influences not only shaping the city but also mapping the mental views of the building. Also, historical conditions and open spaces are one of the inherent elements combined with panoramic view for establishing urban identity. In search for good place making, it is important to understand the role of the historical context and fabric plan in shaping how a resident sees - literally, sees- their city with buildings. Berlin serve as excellent counter example in how the valuable place making panoramic mental views of urbanities take shape.

Effect of Triton X-100 on Compactin Production from Penicillium citrinum

  • Park, Du-Bok;Cho, Ki-An;Cha, Wol-Suk;Ryu, Seong-Ryeol
    • Biotechnology and Bioprocess Engineering:BBE
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    • 제9권3호
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    • pp.171-178
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    • 2004
  • Glucose alone was found to be the most effective carbon source for producing compactin. An initial glucose concentration of 40 g/L gave the highest compactin concentration of 250mg/L. Among the various nitrogen sources, when 5g/L of pharmamedia and soybean meal as the sole nitrogen source were used, respectively, the compactin concentration was higher than 250mg/L. Especially, in the case of the mixture of 6 g/L of pharmamedia and 8 g/L of soybean meal, the compactin concentration was 400mg/L. To select the best surfactant for effective compactin production, various surfactants were investigated. When Triton X-100 was used, the maximum compactin concentration was 445mg/L. With the initial concentration ranging from 1.5 to 2.0 g/L, the compactin concentration was the highest at 465-450mg/L. The cell concentration was similar to that of the control without the addition of Triton X-100. On the other hand, when the above 4.0 g/L of Triton X-100 were used, the cell concentration decreased. Using the based results, the continuous fed-batch cultures by adding the Triton X-100 were carried out for 10 days in an air-lift bioreactor. When 1.5 g/L of Triton X-100 was added to the culture broth at 0, 4, and 8 days of culture, respectively, the compactin production was increased with the increase of culture time. The maximum compactin concentration after 10days of culture was 1,200mg/L, which was about 2.0-fold higher than that of the control without the addition of Triton X-100.

고령사회 주민공유공간의 발전방향에 관한 연구 (A Study on the Improvement of Shared Space for Aging society)

  • 김혜진;이연숙;윤혜경
    • 한국실내디자인학회:학술대회논문집
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    • 한국실내디자인학회 2008년도 춘계학술발표대회 논문집
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    • pp.214-219
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    • 2008
  • The aging of the population has been in process all over the world including most of advanced countries. With the improvement of living standards and medical technology due to the growth and development of the modern industrial society, the continuous Increase of the average lifespan has led to an abrupt growth in the population ratio of the aged. The senescence is the period where both physical and mental functions get dwindled, and due to a loss of roles in a society and a weakened social bond, the elderly people feel often neglected and isolated. Consequently, the elderly people spend a lot of time in their houses. As this means that the elderly gets higher possibility to stay within housing units and housing complex environment, residents' public space needs to be developed within the housing complex for them. Therefore, constructive programs and plans are required for the elderly who experience distance constraint because of corporal aging, for them to sustain community activities within their housing environment. Contrary to them in the 20th century, the elderly living in the nowadays informational society tend to enjoy their leisure times with arts and cultures and underscore the significance of social exchange under diverse possibility and sustainableness. Thus, it is important to preserve those circumstances to provide continuously them. Thus, the purpose of this paper is to grope a growth direction of residents' public space for the elderly to include them to their community through a socially integrated way by grasping present condition of apartment residents' public space's facilities and to be used practically as a basic housing environment data to raise quality of community life.

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가르치기 어려움에 대한 교육현상학적 검토 : 서양교육사에서 (A Study on Educational Difficulty in the History of Western Education)

  • 고요한
    • 교육철학
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    • 제46호
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    • pp.45-70
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    • 2012
  • The purpose of this study is researching on educational difficulty in the history of western education. In other words, the goal and significance of this paper lies in knowing the essential meaning of education based on the norms of difficulty. The major method for this study is hermeneutical-anthropological pedagogy. My fundamental claim is the following: the essential nature of teaching is difficulty at any instructional condition and situations. Such a discrete idea was clearly identified and confirmed in the process of pedagogical anthropology. That is, through the consciousness of educational difficulty and critical review for the history of western education, I can cleary define the concept of educational difficulty. Educational difficulty was various ways for understanding by all audiences. Namely, various formulars were developed for understanding it according to the age, cultures, nations, ideology, etc.. But there are continuous characters on the way for understanding on educational difficulty. The results on research are as followings. In the primitive age, fundamental difficulty of education lies in the initiation ceremony. At the classical ancient time, the purpose of education was 'Politai' with politike arete, in this educational conditions, instruction have a complex dimension politically as well as psychologically. At the medieval age, educational difficulty lies in the 'Askese' for instructional methods. In the modern and conventional age, educational difficulty is more and more complex and confused on goals, methods, evaluations, etc.. Most of all, the major or key concept of educational difficulty in this world is the conflict between the two instructional principles, that is, objectivism and constructivism in education. At now, the schoolworks for instruction over all educational situations and conditions have a difficulty of traditional as well conventional dilemma. In conclusion, educational difficulty have formal, natural, original attribute and it is general and universal phenomenon.

Mixotrophic Cultivation of a Native Cyanobacterium, Pseudanabaena mucicola GO0704, to Produce Phycobiliprotein and Biodiesel

  • Kim, Shin Myung;Bae, Eun Hee;Kim, Jee Young;Kang, Jae-Shin;Choi, Yoon-E
    • Journal of Microbiology and Biotechnology
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    • 제32권10호
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    • pp.1325-1334
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    • 2022
  • Global warming has accelerated in recent decades due to the continuous consumption of petroleum-based fuels. Cyanobacteria-derived biofuels are a promising carbon-neutral alternative to fossil fuels that may help achieve a cleaner environment. Here, we propose an effective strategy based on the large-scale cultivation of a newly isolated cyanobacterial strain to produce phycobiliprotein and biodiesel, thus demonstrating the potential commercial applicability of the isolated microalgal strain. A native cyanobacterium was isolated from Goryeong, Korea, and identified as Pseudanabaena mucicola GO0704 through 16s RNA analysis. The potential exploitation of P. mucicola GO0704 was explored by analyzing several parameters for mixotrophic culture, and optimal growth was achieved through the addition of sodium acetate (1 g/l) to the BG-11 medium. Next, the cultures were scaled up to a stirred-tank bioreactor in mixotrophic conditions to maximize the productivity of biomass and metabolites. The biomass, phycobiliprotein, and fatty acids concentrations in sodium acetate-treated cells were enhanced, and the highest biodiesel productivity (8.1 mg/l/d) was achieved at 96 h. Finally, the properties of the fuel derived from P. mucicola GO0704 were estimated with converted biodiesels according to the composition of fatty acids. Most of the characteristics of the final product, except for the cloud point, were compliant with international biodiesel standards [ASTM 6761 (US) and EN 14214 (Europe)].

스텔라 맥카트니 니트 디자인에 표현된 친환경 디자인 특성 (Eco-Friendly Design Characteristics of Stella McCartney's Knit Design)

  • 이연희;박선희
    • 한국의상디자인학회지
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    • 제24권3호
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    • pp.17-31
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    • 2022
  • The purpose of this research is to suggest diverse directions for eco-friendly knit designing through analyzing the characteristics of Stella McCartney's knit designs. The first stage of the research was to explore the characteristics of eco-friendly fashion design based on literature review. The next stage was to categorize the characteristics of eco-friendly design found in Stella McCartney' knit fashion based on the precedent analysis. The data collected showed 274 examples from 40 Stella McCartney collections, including Spring, Resort, Pre-Fall, and Fall Ready-to-wear collections between 2013 and 2022. All information was collected using www.vogue.com. As a result, the characteristics of Stella McCartney's knit design were classified into four directopms: 1) Perpetual Naturalism, 2) Cultural Complexity, 3) Practical Functionality, and 4) Subcultural Reproducibility. The first characteristic, 'Perpetual Naturalism' values the continuous symbiosis between animals and human beings, thereby protecting global environmental value. Stella McCartney's knit design continuously showed a longing for nature's beauty through fashion design, which allowed people to enjoy the meaning of symbiosis between human beings and animals. Second, 'Cultural Complexity' is the characteristic that appears in Stella McCartney's knit fashion design when collaborating with various artists and/or mixing traditional knit motives inspired by traditional cultures and retro moods. Third, 'Practical Functionality' is the design characterisitic that allows items to be worn for a long time as it is comfortable, simple, and practical. Stella McCartney's knit designs pursue easy-to-wear designs that are comfortable and have practical designs with simple details. Lastly, 'Subcultural Reproducibility' showed in Stella McCartney's knit designs reflect Hippie culture, which pursued a rejection of conventional values, and promoted sustainable energy. This culture peaked in the 1960s and 1970s, when 'Beatles' were mainly working. Additionally, retro styled knit designs inspired by other various music genres from the 1980s and 1990s appeared in this category as well.

에탄올이 Zymomonas mobilis의 당대사 관련 효소에 미치는 영향 (Effect of Ethanol on Selected Enzymes of the Entner-Doudorff Pathway in Zymomonas mobilis)

  • 박인령;권석흠;이계준
    • 한국미생물·생명공학회지
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    • 제16권5호
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    • pp.402-406
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    • 1988
  • 발효생산된 에탄올의 농도가 Zymomonas mobilis 에서 당대사에 관련된 효소의 역가에 미치는 영향을 조사하였다. 그 결과, glucose kinase 및 glucose 6-phosphate dehydrogenase는 큰 영향을 받지 않았으나 transketolase 역가는 에탄을 농도가 증가함에 따라 심하게 저해됨을 알았다. 따라서 에탄을 농도의 증가에 따른 균성장속도의 감소는 transketolase에 의하여 영향을 받는 것으로 생각되었다.

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교반식 perfusion 생물반응기(IPRS)에서 고밀도 고정상 곰팡이 세포를 이용한 세포내 축적 이차대사산물인 Cyclosporin A 대량생산에 관한 연구 (Studies on Mass Production of Intracellularly-Produced Secondary Metabolite, Cyclosporin A by Use of Immobilized Fungal Cells in Stirred-Tank Immobilized Perfusion Reactor System(IPRS))

  • 전계택;이태호장용근
    • KSBB Journal
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    • 제11권1호
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    • pp.22-29
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    • 1996
  • 고정상곰팡이를 이용하여 세포내 축적 이차대사산 물인 cyclosporin A (Cy A)를 연속적으로 생산하 기 위해 perfusion 고정상연속배양을 수행하였다. 이를 위해 균사형성 생산균주인 T. inflaum을 ce­l lite에 고정화하는 데 필요한 공정을 획기적으로 단 순화시키는 방법을 제시하였다. 교반식 Perfusion 생물반응기 (Immobilized Perfusion Reacter S System, 이후 IPRS로 표기 내에 제한유지 된 고밀 도 고정상균체는 매우 높은 희석속도($0.1hr^{-1}$)에서 도 유리세포를 생산해내는 세포생생기의 역할을 훌 륭하게 수행하였으며, IPRS의 배출구를 통해 연속 적으로 유출되는 고농도의 유리세포(1.0g/$\ell$/hr)는 이차대사 결과 세포내에 축적되는 CyA를 연속생산 하는 데 이용될 수 있었다. 이러한 IPRS공정 운영 은 고정상균체를 배양액으로부터 효과적으로 분리시 키는 decanting column의 개발로 가능했요며, 이로 인해 기존의 연속현탁배양에서 문제시되었던 높은 희석속도에서의 wash-out현상이 극복될 수 있었다. 또한 유출되는 유리세포(relesed-free cell)의 mor-phology를 원형의 conidiospore나 잘게 부서진 my­c celial cell로 구성되어 배양액의 rheology가 뉴튼유 체화될 수 있도록 IPRS공정을 운영함으로써, 기존 의 균사형성 미생물의 현탁배양시 나타나는 배양액 에서의 물질전달 감소현상이 뚜렷하게 개선될 수 있 었다. 유출되는 높은 균체생산성(1.0g/R/hr)을 감안할 때, 균주개발과 production배지의 최척화가 본 IPRS공정개발과 병행되는 경우 기존의 회분식배양 또는 연속현탁배양에 비해 훨씬 효과적 인 생산성 증 대를 기대할 수 있을 것으로 보인다.

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