• 한국수소및신에너지학회논문집
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• 제1권1호
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• pp.15-23
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• 1989

The selective separation of hydrogen from gas mixture containing hydrogen was experimentally studied using $LaNi_5$. The capacity and the rate of hydrogen separation, the purity of recovered hydrogen and the optimum condition of the regeneration of deactivated $LaNi_5$ were investigated. The separation rate and the recovery ratio of hydrogen were slowly decreased with the increase of the number of hydrogen absorption cycle. It was found that this result comes from the deactivation of $LaNi_5$ partly because of the blocking of hydrocarbon compounds in the $LaNi_5$ lattice and partly because of the poisoning of $LaNi_5$ surface by carbon monoxide contained in the gas mixture. The optimum condition for the regeneration of deactivated $LaNi_5$ was obtained by heating in a vacuum to about 637 K. The recovery ratio of hydrogen at the optimum condition was observed to be about 80%. The rates of hydrogen separation were measured in the ${\alpha}$-phase and two phase regions. The rate equations could be expressed as follows ; ${\alpha}$ - phase : $$-\frac{dP{_{H_2}}}{dt}=9.836{\times}10^{-3}(P{_{H_2}}_{-P_{eq}})$$ two phase region : $$-\frac{dP_{H{_2}}}{dt}=1.6909{\times}10^2\exp(-17560/RT)(P{_{H_2}}_{-P_{eq}})$$.

• 한국버섯학회지
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• 제12권3호
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• pp.145-153
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• 2014

Pleurotus has increased rapidly production and consumption because of highly nutritional value, natural healthy food and so on. The basic studies for Pleurotus need for development of mushroom industry. This study was to investigate the cultural characteristics among 15 strains of 6 species and to analyze their phylogenetic relationships. The cultural characteristics were investigated by mycelial growth activity at different media, temperature and pH. The optimum media for mycelial growth were YM and MCM in most species. The optimum temperature for mycelial growth were $25^{\circ}C$ and $30^{\circ}C$. The optimum pH for mycelial growth were widly range from pH 5.1 to 7.4. Through the RFLP (restriction fragment length polymorphism) of IGS (intergenic spacer) I region in ribosomal DNA, it was analyzed phylogeny of interspecies and intraspecies. Each species was discriminated well as isolates within each species formed clade to be distinguished other species. P. florida was highly similar to P. floridanus, and P. flabellatus was P. cornucopiae. P. fuscus var. ferulae was highly similar to P. eryngii but discriminated different species in analysis of RFLP of IGS I region and showed different characteristics in mycelial culture. RFLP of IGS I region was useful of studying phylogenetic relationships of species and population.

• 한국미생물·생명공학회지
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• 제15권6호
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• pp.436-440
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• 1987

앞서 보고한 바와 같이 토양으로부터 분리한 K. pneumoniae NFB-320의 pullulanase 유전자를 pBR 322을 이용하여 E. coli에 cloning한 결과 약 14.4kb 의 재조합 plasmid DNA pYKL451을 얻었다. 이러한 pullulanase 유전자에 대한 유전적 정보를 얻기 위해 여러 가지 제한효소로 단일 혹은 이중 절단을 행하여 삽입된 pullulanase 유전자의 제한효소 절단지 도를 작성하였으며, E. coli(pYKL451)과 K. pneumoniae NFB-320이 생산하는 pullulanase의 효소적 특성을 조사하였다. 생산되는 두 균주의 효소는 50-55$^{\circ}C$ 부근에서 최적온도를 나타냈으며 최적pH는 모두 6.0이었다. 효소 안정성에 미치는 pH의 영향은 4$0^{\circ}C$에서 90min 간 방치했을 때 pH 5.0-10.0에서 안정하였으며 열안정성은 (pH6.0) 각 온도에서 한시간 처리하였을 때 4$0^{\circ}C$까지는 안정하였으나 5$0^{\circ}C$ 이상에서는 효소의 활성이 급격히 감소하였다.

• 대한환경공학회지
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• 제27권2호
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• pp.184-190
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• 2005

하수 슬러지를 펜톤 산화공정으로 처리하는 새로운 VFAs 생산 공정을 연구하였다. 과산화수소와 촉매인 $Fe^{2+}$의 적정농도를 실험하고, 최적 반응온도 및 반응시간에 대한 기초 자료를 얻고자 하였다. 기존의 과산화수소를 액상산화제로 사용한 공정보다 저농도의 $Fe^{2+}$를 촉매로 사용하는 펜톤 산화공정으로 과산화수소의 사용량을 대폭 감소시키고도 VFAs 생성량이 4배 정도 증가하는 결과를 얻었다. 과산화수소와 $Fe^{2+}$의 적정 농도는 각각 0.62 M과 0.007M 이었다. VFAs 생성반응은 초기 1분 이내에서 빠르게 진행되었으며 생성된 VFAs의 일부가 초산과 $CO_2$로 분해되는 연속반응의 특성이 나타났다. 경제성을 감안하면 반응온도는 $25^{\circ}C$, 반응시간은 10분 정도가 적절한 반응조건으로 생각된다. 초기 pH $3{\sim}6.3$에서 VFAs의 생성에 미치는 pH의 영향은 관찰되지 않았다.

• 한국미생물·생명공학회지
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• 제31권2호
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• pp.145-150
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• 2003

Acinetobacter sp. SY-01가 생산하는 lipase는 소염진통제로 쓰이는 azolerP 의약품 중간체인 두 enantiomer를 가진 rcemate에 대해 enantioselectivity를 가지는 효소로써 chiral drug를 생산하는데 있어 중요한 역할을 수행한다. Acinetobacter sp. SY-01 lipase 효소의 다량 생산을 위한 여러 가지 최적 조건을 조사하였다. 탄소원으로는 여러 가지 천연 오일을 이용하여 실험한 결과 0.2% olive oil이 가장 좋았으며, 최적 온도와 pH는 30도와 pH 7이였다. EH한 금속이온과 유기용매 안정성에 있어서는 $Fe^{2＋}$ 과 $Ca^{2＋}$ DMSO가 좋은 효과를 나타냇었다. 특히 DMSO는 유기용매가 첨가되지 않았을 때보다 약 2.5배 높은 효소 활성을 나타내었다. 계면활성제 이용에 있어서는 tritom X-100을 이용했을 때 좋은 효과를 나타냈다. Acinetobacter sp. SY-01가 생산하는 lipase 효소의 최적 배지 조성은 0.8% yeast extract, 0.2% olive oil 0.4% triton X-100, 40% DMSO, 0.1 % $NH_4$Cl% 0.4%$K_2HPO_4$ 3.9% $NaH_2PO_4$ 0.03% $CaCl_22H_2O$ 0.01% $FeSO_4$$7H_2O$(pH 7.0)이다.

• 한국환경보건학회지
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• 제29권2호
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• pp.1-6
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• 2003

This paper reports on a pilot scale comparison of PACS coagulation with and without pH preadjustment. The pH of the water was adjusted with carbon dioxide and sulfuric acid. Process performance was assessed on the basis of total organic carbon(TOC), UV absorbance, turbidity and disinfection by-product(DBP) precursors. Coagulation pH appeared to be a determining factor for maximum NOM removal. The optimum coagulation pH in order to decrease TOC and turbidity were pH 7. Preadjustment of pH 7 increased TOC removal to as much as 43, 47 percent with sulfuric acid and carbon dioxide. Moreover, coagulation at pH 7 caused a reduction in UV$_{254}$, THMFP and HAAFP compared to the baseline coagulation. For preadjustment of pH 7 with carbon dioxide, the percentage of TOC, UV$_{254}$, THMFP and HAAFP shows the reduction rate of 3.8, 0.5, 4.8, 9.4％ comparing to the coagulation rendition using sulfuric acid. Acid addition to depress pH during coagulation decrease Langelier Saturation Index(LSI), potentially causing increase corrosion in water distribution systems. LSI for carbon dioxide and sulfuric acid at pH 6 was -2.3, -3.3. Therefore, carbon dioxide was more effective at controlling corrosion than sulfuric acid.

• BMB Reports
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• 제32권2호
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• pp.127-132
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• 1999

The NAD(P)H-quinone oxidoreductase (EC 1. 6. 99. 2) was purified from S. cerevisiae. The native molecular weight of the enzyme is approximately 111 kDa and is composed of five identical subunits with molecular weights of 22 kDa each. The optimum pH of the enzyme is pH 6.0 with 1,4-benzoquinone as a substrate. The apparent $k_m$ for 1,4-benzoquinone and 1,4- naphthoquinone are 1.3 mM and $14.3\;{\mu}M$, respectively. Its activity is greatly inhibited by $Cu^{2+}$ and $Hg^{2+}$ ions, nitrofurantoin, dicumarol, and Cibacron blue 3GA. The purified NAD(P)H-quinone oxidoreductase was found capable of reducing aromatic nitroso compounds as well as a variety of quinones, and can utilize either NADH or NADPH as a source of reducing equivalents. The nitroso reductase activity of the purified NAD(P)H-quinone oxidoreductase is strongly inhibited by dicumarol.

• 미생물학회지
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• 제5권1호
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• pp.20-23
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• 1967

I studied about temperature and pH concentration having influence upon chlorophyll decrease on the Glucose culture of Chlorella variegata Beijerinck(211/10a). I cultured under $25^{\circ}C$(standard), $15^{\circ}C$ and $35^{\circ}C$ and compared with each other. The culture of $15^{\circ}C$ didn't have any large difference with the standard culture($25^{\circ}C$) but the culture of $35^{\circ}C$ had a large amount of chlorophyll decrease without carbohydrate accumulation, stimulation of cell division and nitrogen-deficiency. Chlorella variegata had optimum pH 6.5-7 and was a little weak in all phenomenon under pH 8 rather than under pH 6.5-7. Under pH 5 they had deep chlorophyll decrease without phephytin.

• 한국균학회지
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• 제24권2호통권77호
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• pp.149-154
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• 1996

느타리버섯 균사를 톱밥에 배양할 때 분비되는 여러 가지 extracellular enzyme중 pretense, phenoloxidase, cellulase가 배양조건을 달리하였을 때 변화양상을 요약하면 먼저 톱밥의 종류에 따라서는 참나무톱밥에 비해 포플라톱밥이 specific activity가 높은 경향이었다. 첨가제 종류에 따라서는 밀기울에 비해 미강이 약간 높았으며 혼합비율이 30, 20, 10%순으로 높았다. 수분함량은 3가지 효소 모두 70%에서, 배지의 PH에 따라서 protease는 pH 4와 9, cellulase는 pH6, phonoloxidase는 pH 5와 7, 배양온도는 3가지 효소 모두 $25^{\circ}C$, 목초액 농도에 따른 pretense와 phonoloxidase는 무처리가 처리보다 총활성이 높았으며, cellulase는 0.5%에서 총활성이 가장 높았다.

• 대한치과기공학회지
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• 제21권1호
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• pp.139-144
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• 1999

토양시료로부터 치아우식원인균인 S. mutans에 대하여 항균력을 나타내는 방선균주를 순수분리하여 분리균주를 공시균주로 하여 항생물질 생성에 미치는 환경인자를 규명하였다. 본 공시균주의 항생물질 생성 최적배지조성은 Bacto-soytone 1%, glucose 1%, NaCl 0.5%, $CaCO_3$ 0.1% 였으며 배지의 초기 pH는 7.0이었다. 또한 항생물질은 $28^{\circ}C$에서 진탕배양시 생성의 최적조건이었으며 본 공시균주는 24시간 유도기를 거쳐 배양 72시간째 항생물질의 생성과 더불어 균의 최대증식도를 나타내었다.