• Applied Biological Chemistry
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• v.38 no.4
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• pp.308-312
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• 1995

The effects of nitrogen, phosphate in modified B5 medium and cell immobilization on cell growth and taxol production were investigated using cell cultures of Taxus cuspidata. The ratio of nitrate to ammonium was found to be an important parameter. The ratio of 1 increased taxol production 10-fold, compared to the original ratio of 20 in modified B5 medium. Reducing phosphate concentration inhibited cell growth, but increased taxol production noticeably. Immobilized cells produced a taxol concentration of ${\sim}120\;g/l$

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1979.10a
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• pp.248.2-248
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• 1979

식초산 발효 실험을 통하여 다음과 같은 결과를 얻었다. 1. 자연에서 초산균 52균주를 분리하고 그중 식초산 농도 5.5% 이상되는 초산균 CAU-4, CAU-15, CAU-17, CAU-46, 4균주를 선별하였다. 2. 정치배양과 진탕배양을 실시한 결과 산생성랑은 진탕배양에서 월등한 효과를 보였다. 3. 유기태 질소원의 첨가시 peptone을 0.4%까지 증가를 보였고, yeast extract는 0.1~0.2%가 최적량이고 그 이상은 산량이 감소되었다. 4. $NH_4NO_3의$ 자화성을 조사한 결과 CAU-17만이 자화하지 못하였고, 무기태 질소원으로서는 $(NH_2)_2CO가$ 가장 좋았다. 5. 무기염류는 $KH/_2PO_4,$ $MgSO_4.7H_2$ O 0~0.1% 첨가하여 약간의 효과를 보았다. 6. Glucose의 첨가량별 산량의 증가는 0.25% 첨가시 0% 첨가시 보다 증가를 보인 반면 1% 첨가시는 오히려 감소하였다. 7. 초발 alcohol농도가 낮을수록 유도기와 대수기가 단축되며 10%이상에서는 4균주 모두 산을 생성하지 못하였다. 8. 초발산도가 높을 경우 유도기가 길어지고 산생성량이 줄어 들었다. 9. 초산균의 배양온도는 $30^{\circ}C,$ $35^{\circ}C에서$ 산생성 속도가 가장 빨랐다. 10. 발효시 산생성량에 따른 세균수의 증가는 접종후 2~3일 사이에 가장 많았다. 11. 초산의 증가와 더불어 균체량은 증가하였고 pH는 약간색 감소하나 PH는 2.5이하로는 내려가지 않았다. 12. alcohol 잔량은 발효 개시 후 5 ~6일의 정지기에 가장 낮았다.

• The Korean Journal of Mycology
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• v.23 no.4 s.75
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• pp.348-353
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• 1995

Biodegradability of poly (3-hydroxybutyrate) (PHB) by Penicillium pinophilum was investigated by the modified Sturm Test. The biodegradability measurement by this method was more reproducible than other conventional activated sludge methods. Optimum inoculum size for the PHB biodegradation was 1% (v/v). The degradation appeared to occur not only on the sample surface but also inside the sample because the biodegradation did not increase quite proportionally with the sample surface area. The biodegradation rate increased to an asymptotic value as the nitrogen content in the test medium increased, indicating the nitrogen source was needed for the synthesis of the PHB depolymerase.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.346-347
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• 2012

최근 화석연료 대체 에너지원으로서 자동차용으로 연구 개발 및 응용되고 있는 고분자 전해질 연료전지(PEMFC: Proton exchange membrane fuel cells)에서 분리판(Bipolar Plate)은 스택 전체 무게의 80%, 스택 가격의 60% 정도로 가장 높은 비중을 차지한다. 분리판은 연료와 산화제를 공급해주는 통로 및 전지 운전 중에 생성된 물을 제거하는 통로 역할과 anode, cathode로서 전극 역할을 통해 스택 전력을 형성하는 핵심 기능과 전지와 전지 사이의 지지대 역할을 한다. 따라서 분리판은 전기전도성, 내부식성 및 기계적 특성이 우수해야함은 물론이고, 얇고 가벼우며 가공성이 뛰어나야 한다. 현재 가장 많이 사용되고 있는 금속 분리판 소재 중 스테인리스 스틸은 전기적, 기계적 특성 및 내부식성이 우수한 반면, 가격이 비싸고, 중량이 무거운 단점이 있다. 따라서 본 연구에서는 DC 반응성 마그네트론 스퍼터링법으로 전기적, 기계적 특성 및 내부 식성이 우수한 TiN, TiCN 박막을 스테인리스에 비해 중량이 1/3, 소재 단가가 1/4인 알루미늄 기판 위에 증착하여 박막 물성을 평가하였다. DC Power는 400 W, 기판과 타겟 사이의 거리는100 mm, 공정 압력은 0.5 Pa로 고정하였고, 3 inch의 지름과 순도 99.95%를 갖는 티타늄 타겟을 사용하였다. 공정 가스는 Ar을 주입하였으며, 질소와 탄소의 공급원으로는 질소($N_2$)와 메탄($CH_4$) 가스를 사용하여 챔버 내 주입혼합가스의 전체 유량을 50 sccm으로 고정시켰다. 증착된 박막의 전기적, 기계적 특성을 측정하였고, X-ray diffraction (XRD), Scanning electron microscope (SEM)을 이용하여 박막의 미세구조 및 표면 상태를 확인하였다. 또한, 내부식 특성을 평가하기 위해 potentiostatic, potentiodynamic 법을 이용하여 박막의 부식저항을 측정하였다. 증착된 TiN 박막의 경우 질소 함량의 증가에 따라 박막 증착속도는 감소하는 경향을 보였다. 이는 타겟 부근의 질소 라디칼 비율이 증가함에 따라 질화반응이 촉진된 것으로 생각된다. 또한, 증착된 TiN과 TiCN 박막은 반응성 질소 유량과 탄소 유량에 따라 각각 다른 미세구조를 가지는 것을 확인하였다. TiN과 TiCN은 NaCl형의 면심입방격자(FCC)로 같은 구조이며, 격자상수가 비슷하여 전율고용되어 TiCN을 형성하고, 탄소와 질소의 비에 따라 전기적 기계적 특성이 달라짐을 확인하였다.

• The Korean Journal of Mycology
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• v.24 no.4 s.79
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• pp.305-309
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• 1996

The conditions for mycelial production of mushroom rising rancid oil of fried chicken were investigated. Pleurotus ostreatus Nonggi 202 which showed the greatest mycelial growth among mushrooms was chosen for the investigation. The optimum temperature and pH for mycelial growth were $25^{\circ}C$ and 5.5 to 6.5, respectively. Tryptone was better effective than any other nitrogen sources on the mycelial growth. The mycelial growth was enhanced with addition of 0.3% $KH_2PO_4$. and 0.02% $MgSO_4$, respectively. Among the vitamins, thiamine was the most effective on the mycelial growth.

• Microbiology and Biotechnology Letters
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• v.13 no.3
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• pp.257-263
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• 1985

Rhodopseudomonas sp. KCTC 1437 evolved molecular hydrogen efficiently under light illuminated anaerobic culture condition in the presence of organic acids and various sugars. especially glucose when low concentration of NH$_4$ + or L-glutamate was added to cultures. It was revealed that hydrogen formation from Rhodopseudomonas sp. KCTC 1437 was mediated by two different enzyme systems. Under the nitrogen limiting condition, hydrogen evolution from glucose was catalyzed by nitrogenase. For the nitrogenase activation in vivo, the precultured cells drown on limiting concentration of NH$_4$$^{+}$ as a sole nitrogen source showed more capacity of hydrogen evolution from glucose in the presence of L-glutamate than any other cells .frown on sufficient concentration of NH$_4$$^{+}$, L-glutamate, NH$_4$$^{+}$, or both of L-glutamate and $N_2$. A significant volume of molecular hydrogen was evolved from glucose even in the presence of excess NH$_4$$^{+}$ either in the light or dark anaerobic condition, presumably due to the mediation of hydrogen evolution by fromic hydrogenlyase.enlyase.

• Journal of Soil and Groundwater Environment
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• v.8 no.2
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• pp.36-43
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• 2003

Feasibility of micellar-enhanced ultrafiltration far the removal of nitrate was investigated using cationic surfactants, cetylpyridinium chloride and octadecylamine acetate. The removal of nitrate increased as the molar ratio of surfactant increased. With the molar ratio of 3, at least 80% of nitrate was removed, while > 98% of nitrate was removed at the surfactant molar ratio of 10. Octadecylamine acetate showed higher removal efficiency of nitrate and higher rejection of surfactant than cetylpyridinium chloride because of the accessibility of nitrate to surfactant micelles due to head group of surfactant. Octadecylamine acetate turned out to be a better surfactant than cetylpyridinium chloride for micellar-enhanced ultrafiltration to remove nitrate from groundwater.

• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.242-251
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• 2012

To investigate foodweb of aquatic ecosystem in the Tamjin River, carbon and nitrogen stable isotopes ratios of aquatic organisms, as well as environmental indicators based on the water, were determined in this study. Various organisms such as fishes (Coreoperca kawamebari, Zacco platypus, Cobitis lutheri, and Pungtungia herzi) and periphyton (epilithon and epiphyte), and particulate- and coarse particulate organic matters (POM and CPOM) were collected in upper (Tamjin River, Yuchi Stream, and Omcheon Stream) and lower (TJ-1~TJ-5) reaches of Jangheung Dam. The nitrate concentration and ${\delta}^{15}N$ signature of POM and organisms (invertebrates and fish) were found to be more enriched toward the downstream section of the river. It was determined that allochthonous matter occurring from a tributary alters the chemical character of water, as well as the isotopic signature of organisms contained therein. Attached algae (ephilithon) were identified as a base component of the benthic foodchain further downstream.

• Korean Journal of Microbiology
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• v.42 no.2
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• pp.131-134
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• 2006

The culture conditions for the enhanced mycelial of Clavicorona pyxidata DGUM 29005 were investigated. The optimal temperature and pH for the mycelial growth were $24^{\circ}C$ and 5.0, respectively. It was shown that trehalose was the best supplement of carbon sources in Czapek-Dox medium as a minimal medium for enhanced mycelial growth. In general, inorganic nitrogen sources were better than organic ones for mycelial growth. Calcium nitrate was the best out of the inorganic nitrogen test. The appropriate phosphorous and vitamin were $Na_2HPO_4$ and p-aminobenzoic acid, respectively. After the mycelial of C. pyxidata DGUM 29005 was cultivated at $24^{\circ}C$ for 20 days in MEM broth(pH 5.0), the specific activities of both exomycelial and endomycelial enzymes were determined. Among the exomycelial enzyme assayed, the specific activity of laccase was much higher than those of other enzymes. However, little or no enzyme activities of ${\alpha}$-amylase, chitinase, lipase and pretense were found.

• The Korean Journal of Mycology
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• v.22 no.2
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• pp.145-152
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• 1994

In order to investigate the cultural characteristics of Lentinus lepideus, media, pH, carbon sources, nitrogen sources, vitamin and organic acids were tested in submerged culture. It grew well in GPB(broth), and the optimum temperature and pH was $25^{\circ}C$ and 4.2, respectively. The carbon sources such as galactose belong to monosaccharide and maltose belong to disaccharide were effective for mycelial growth. Peptone which is compound nitrogen source was good for mycelial yield but the other nitrogen sources were not effective. Among the various vitamins, pyridoxine is suitable for mycelial yield. Among the various organic acids, citric acid promoted the mycelial yield but acetic acid interrupted the mycelial growth of L. lepideus.