Aspergillus속이 생성하는 Pectin Esterase 의 효소학적 성질

유대식,송형익,정기택 한국균학회 1981 韓國菌學會誌 Vol.9 No.1

The enzymatic properties of pectin esterase from Aspergillus sp. were studied. The optimum conditions for the enzyme reaction were pH 4.2 and temperature of 45℃. The crude enzyme was very stable at pH range of 2.2∼4.6, but about 20 percent of activity was lost at the range of pH 5.4∼8.0. The crude enzyme was very stable at 50℃ for one hour, however almost 100 percent of enzyme activity was lost at 70℃ for 30 minutes. The pectin esterase activity of crude enzyme was greatly inhibited by addition of sodium chloride at lower pH range. That is, the inhibition rates of enzyme activity at pH 3.0 and 4.0 were 47% and 28% in concentration of 1M sodium chloride, respectively. The enzyme activity was not affected by sodium chloride at pH 7.0 at different concentration of sodium chloride. Although the enzyme activity was not affected by addition of sucrose, it was slightly inhibited at higher concentration of sucrose.

Bacillus polymyxa YL38-3의 세포외 cytosine deaminase 생성의 최적 배양 조건

유대식,김대현,박정문,송형익,정기택 한국미생물학회 1988 미생물학회지 Vol.26 No.4

The strain YL 38-3, which was capable of producing extracellular cytosine deaminase, was isolated and taxonomically examined. The isolated strain was identified to be Bacillus polymyxa YL 38-3. The optimal conditions for the enzyme production from Bacillus polymyxa YL 38-3 were investigated. The enzyme production was reached maximum level in the medium containing 0.5% glucose, 0.2% beef extract, 0.5% NaCl and 0.1% $KH_{2}PO_{4}$ (pH 6.0). And the enzyme showed the highest activity when the strain YL 38-3 was cultivated at $35^{\circ}C$ for 24 gours under the initial pH 6.0. By the additions of peptone the extracellular enzyme production was inhibited, meanwhile the intracellular enzyme production was highly stimulated. It was, therefore, deduced that peptone was related to the secretion mechanism of the enzyme from this bacterial cell.

세포외 Cytosine Deaminase의 효소학적 성질

유대식,김대현,박정문,송형익,정기택 한국미생물학회 1988 미생물학회지 Vol.26 No.4

Bacillus polymyxa YL38-3이 생성하는 세포의 cytosine deaminase의 효소학적 ,성질을 검토하였다. 본 세포외 효소는 열 안정성이 높으며, 인산완충액(pH6.0)과 $30^{\circ}C$에서 효소활성이 최대를 나타냈다. 본 효소는 cytosine 뿐 아니라 5- fluorocytosine-을 기질로 하나, 5-methylcytosine은 촉매하지 않았다. 더우기 본 효소는 $Cd^{2-}$, $Hg^{2+}$의 중금속이온과 ImM p-chloromercuribenzoate에 의하여 완전히 실활되며, o-phenanthroline과 monoiodoacetate에 의하여 75% 저해되었다. 그러나 1mM 2-mercaptoethanol에 의하여 본 효소의 활성을 약 200% 이상 활성화시켰다. Enzymological proprties of an extracellular cytosine deaminase from Bacellus polymyxa YL 38-3 were investigated. The extracellular enzyme was very stable, and optimum pH and temperature for the enzyme activity were found to be near pH 6.0 in 0.2M potassium phosphate buffer and at $30^{\circ}C$, respectively. 5-Fluorocytosine was converyed to 5-fluorouracil by the enzyme, but 5-methylcytosine was not to thymine by it. The enzyme activity was completely inhibited by some heavy metal ion such as 1mM of $Cd^{2-}$ and $Hg^{2+}$, and by 1mM of p-chloromercuribenzoate, respectively. The enzyme activity was inactivated about 75% by 1mM of o-phenanthroline and monoiodoacetate. But the enzyme activity was stimulated up to 200% by 1mM of 2-mercaptoethanol.

카드뮴의 Hansenula anomala 세포내 축적에 미치는 Triton X-100의 효과

유대식,박정문,송형익 한국미생물학회 1987 미생물학회지 Vol.25 No.2

고도 카드뮴 내성효모 Hansenula anomala B-7의 균체내에 다량의 카드뮴을 축적시키기 위하여 배양시 계면활성제를 첨가하여 배양하는 방법을 검토했다. 계면활성제 중 비이온계인 Triton X-100에 의하여 약 40%의 카드뮴의 축적효과를 나타내며 유효농도는 0.1-0.2%였다. 균체내 카드뮴 축적의 최적조건은 다음과 같다. 정치배양보다 진탕배양이 효과적이었으며, 48시간 진탕배양으로 카드뮴의 균체내 축적이 최대에 도달했으며 배지의 초기 pH는 6.0이었으며, 배양온도는 $40^{\circ}C$가 양호했다. As a pary of investgation on effective accumulation of cadmium in yeast cells, effect of surfactant was studied on intracellular accumulation of cadmium in extremely cadmium-tolerant yeast, Hansenula anomala B-7. Cadmium accumulation was enhanced up to approximately 40% by the addition of non-ionic surfactant, Triton X-100 and its optimal concentration was found to be 0.1-0.2%. Furthermore, optimum conditions for intracellular accumulation of cadmium were at $40^{\circ}C$ and initial pH 6.0 for 48 hours under shaking culture.

카드뮴 내성 효모의 세포내 카드뮴 축적 기작

유대식,송형익,정기택 한국미생물 · 생명공학회 1990 한국미생물·생명공학회지 Vol.18 No.3

The mechanism of intracellular accumulation of cadmium in a cadmium-ion tolerant yeast, Hansenula ammala B-7, which is an extreme cadmium tolerant strain and has the ability to take up a large amount of cadmium was investigated. The amounts of cadmium taken up by the scalded yeast cells were 2 to 3 times more than the value of the living cells. The living Hansenula anomala B-7 cells adsorbed 74% of cadmium taken up onto the other layer of the cells and 26% of it accumulated inside the cells. But the scalded cells adsorbed 98.3% of cadmium taken up and accumulated 1.7% of it inside the cells. A cadmium uptake and its accumulation were accelerated up to 162.3% and 275.4% by Triton X-100 in the living cells, respectively. Whereas in the scalded cell cadmium uptake was not affected by Triton X-100. Furthermore the cadmium uptake and its accumulation were strongly inhibited by metabolic inhibitors like 2,4-dinitrophenol, sodium azide and potassium cyanide in the living cells, but in the scalded cells cadmium uptake was not affected by metabolic inhibitors. These results suggested that the intracellular accumulation of cadmium by the cadmium-tolerant Hansenula anomala B-7 cells was apparently dependent of biological activity, and also gave evidence of the existance of energy-dependent system.

絹의 酵素精練

金孝垠,咸玉相,兪大植 啓明大學校 生活科學硏究所 1985 科學論集 Vol.11 No.-

The following conclusions result from examing how the degumming loss changes according to the treating time, the treating temperature, PH, the concentration of papain, and the concentration of protective agent when raw silk is dipped in solution to the amount of 50 times of the material and then comparing protease degumming with soap degumming. 1. Degumming can be effectively done at the temperature of 65℃. And for 30 minutes because the degumming for a long time causes lousiness. 2. The activity of the protease increases in proportion to the PH increase until the activity of the protease sharply falls down beyond PH5. Thus PH5 is most proper for degumming. The protease concentration of 0.10% is suitable for degumming. 3. L-Cystine scores 157.08% and works best of several protective agents. When degumming is performed in the various concentration solutions, 0.2% L-cystine shows 93.94% activity, the most effective result. 4. Soap degumming shows 21.79% degumming loss and protease degumming 19.83%. It proved that the effective degumming is done with the degumming loss 34.20% when soap degumming is applied after the protease degumming. 5. When the surfaces of the untreated raw silk and the treated one were examined by the electronic-microscope, the soap degumming in comparison with the protease degumming removed sericin a little. The raw silk treated in soap degumming after the protease degumming revealed little sericin.

Streptococus zooepidemicus에 의한 히아루론산의 생산

유대식 한국생물공학회 1992 KSBB Journal Vol.7 No.2

Streptococcus zooepidemicus에 의한 hyaluronic acid 생성의 최적 배지 조성은 batch cultre 조건에서 0.1% 쇠고기 추출물, 0.1% 효모 추출물, 3.0% 포도당 2.0% peptone, 0.1% 식염 및 0.5% $CaCO_3$이였으며, 배지의 포기 pH는 7.5로서 $37^{\circ}C$에서 36시간 진탕배양하는 것이 양호했다. 특히 공시균의 생육에 수반되어 hyaluronic acid가 생성되므로 배지의 pH를 중화하기위해 $CaCO_3$의 첨가는 필수적이었다. An optimal composition of medium for hyaluronic acid production and some characteristics of its from Streptococcus zooepidemicus were investigated. The hyaluronic acid from S. zooepidemicus was reached maximum level in the BY-medium containing 0.1% beef extract, 0.1% yeast extract, 3.0% glucose, 2.0% peptone, 0.1% NaCl and $0.5%CaCO_3$ (pH 7.5) at $37^{\circ}C$ for 36 hours with shaking. Addition of $CaCO_3$ to the medium was necessary to neulralize the lowered pH which was resulted from hyaluronic acid production. Molecular weights of extracelluar and cellular hyaluronic acid produced by the strain were $1-1.4{\times }10^6$ and $5{\times}10^6$, respectively. The amount of extracellular hyaluronic acid was 91.9% of total hyaluronic acid produced and the vest was all intracellular.

카드뮴이 카드뮴 내성 효모세포내의 효소 활성에 미치는 영향

유대식,박은규,박정문 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.3

카드뮴에 의하여 고도 카드뮴 내성 효모인 Hansenula anomala B-7 세포내 효소생성의 변화를 관찰하여 대사계의 변화를 추정했다. 1.0mM 카드뮴에 의하여 공시균의 alcohol dehydrogenase의 생성은 무첨가에 비하여 90% 이상 감소하나 malate dehydrogenase의 생성은 440% 증가되어, 카드뮴에 의하여 혐기적 대사계는 억제되고 호기적 대사계인 TCA 회로는 활성화되었다. 그리고 1.0 mM 카드뮴에 의하여 공시균의 해당계 효소인 phosphofructokinase의 생성은 약 40% 감소되었으나, 당의 호기적 분해대사계 효소인 6-phosphogluconate dehydrogenase의 생성은 약 136% 증가되어, 카드뮴에 의하여 EMP 대사계는 활성화되었다. 더욱이 1.0 mM 카드뮴에 의하여 공시균의 cytochrome c oxidase와 alkaline phosphatase의 생성의 각각 260%와 155% 증가되었다. 이상의 결과를 종합하면 카드뮴에 의하여 혐기적 대사계는 억제되나, 호기적 대사계는 활성화되며, 이로 인하여 생성된 다량의 NADH와 NADPH의 산화를 위하여 cytochrome c oxidase의 활성화는 필연적으로 요구되었다. 그리고 pyrimidine nucleotide 분해대사계 효소인 cytidine deaminase의 생성은 1.0mM 카드뮴에 의하여 약 86% 감소되어, 카드뮴은 necleotide 분해를 억제한다고 추측할 수 있었다. An extremely cadmium tolerant yeast, Hansenula anomala B-7 used to determine the modification of the intracellular enzyme activities by cadmium ion. The activities of alcohol dehydrogenase, phosphofructokinase, and cytidine deaminase were decreased up to 90%, 40%, and 86% compared with the control by mM cadmium nitrate respectively, but the activites of malate dehydrogenase, 6-phosphogluconate dehydrogenase, cytochrome c oxidase, and alkaline phosphatase were increased up to 440%, 136%, 260% and 155% compared with the control by 1 mM cadmium nitrate respectively. These show that the activities of the enzymes participating in Emboden-Mayerhof pathway (e.g. anaerobic metabolism) were reduced by cadmium, but those involved in hexose monophosphate pathway and tricarboxylic acid cycle (e.g. aerobic metabolism) were stimulated in contrast. It has been suggested that the diminished activity of cytideine deaminase in pyrimidine nucleotide dissimilation occured due to the inhibited nucleotide dissimilation by cadmium ion; the enhanced activity of cytochrome c oxidase was specifically required in order to oxidize a raised amount of NADH and NADPH due to the increased aerobic metabolism.

과실주 (果實酒) (사과주) 양조에 관한 연구 : 저농도주정함유 (低濃度酒精含有) 사과주에 관하여 Apple wine containing lower concentration of alcohol

유대식,홍순덕,송형익,정기택 한국균학회 1978 韓國菌學會誌 Vol.6 No.1

This study aims to brew apple wine containing lower concentration of alcohol by fermentation and to retain CO₂ gas in apple wine, and investigation for the possibility of storage at room temperature was performed. A Saccharomyces sp. was proved to be acceptable for production of base wine as its higher fermentation rate at 20∼25℃. However, B-2 was most reasonable for post-fermentation of apple wine as this strain strongly ferments sugars at low temperature (4℃). The yield of apple juice increased by maceration of apple pulps. The yield was about 5% more than that of the unmacerated juice, whereas acid content was decreased by 10% compared with control. When stored apple wine containing 9% alcobol was introduced 1∼3% sucrose at 7∼8℃ for 100 days or more, the CO₂ pressure of apple wine in bottle shows 3㎏/㎠ by bottle-pressure meter. It showed good storage of the wine at room temperature. CO₂ gas pressure in apple wine containing 6% alcohol, 5∼10% hop extract, and 2% sugar was 2㎏/㎠. he result also showed possibility of storage. Whereas 6% concentration of alcoholic apple wine without hop extract caused unusual fermentation during storage at the same condition. The desirable conditions for high quality apple wine should have CO₂ pressure of 2㎏/㎠ or more and should be added 1∼2% sugar to base wine. From these results, it can be concluded that the brewing of lower alcoholic apple wine is possible.

한국생물공학회 총서 6 천년의 술, 우리 막걸리

유대식 한국생물공학회 2016 BT NEWS Vol.23 No.2