성층 절연물의 절연파괴전압에 관한 연구

이계호(K. H. Lee) 대한전기학회 1965 전기의 세계 Vol.14 No.1

Laminated insulators are largely used in the insulation of electric apparatus. This reason is based on the fact that the solid state insulators meet to electrical break-down by the weak spot theory. Thus the break-down voltage of the laminated insulators are generally affected by the density, distribution and the form of the weakspot contained in the each laminated thin insulator. In this experiment the effects of the characterics of weak spots are not studied, but the effects of the number of lamination and the pressure applied on the laminated insulator on its break-down voltage are investigated experimentaly, and got some interesting results which are reparted as follows.

멸치젓의 呈味性 5'-Mononucleotides에 關한 硏究

李春寧(C. Y. Lee),李啓瑚(K. H. Lee),金榮洙(H. S. Kim),韓仁子(I. J. Han),金尙淳(S. S. Kim) 한국식품과학회 1969 한국식품과학회지 Vol.1 No.1

protoplast-fusion에 依한 澱粉에서 Ethanol의 單段醱酵能 酵母 開發 : I. Characteristics of two yeast strains and conditions for the protoplast formation and reeneration as a preliminary step in interspecific protoplast-fusion I. Interspecific Protoplast-fusion 을 爲한 酵母菌林의 諸特性과 Protoplast 調製 및 Regeneration 條件

吳秉夏,黃殷成,李炯周,李啓瑚,朴官和,張海東,徐鉉昌 서울大學校農科大學 1984 서울대농학연구지 Vol.9 No.1

澱粉으로 부터의 alcohol 醱酵能을 增進시키기 爲하여 澱粉糖化性 菌株인 Saccharomyces diastaticus와 優秀한 alcohol 醱酵性 菌株인 Saccharomyces uvarum을 母菌株로 하여 이들간의 同屬異種間 原形質融合(interspecific protoplast fusion)을 通한 優秀한 澱粉醱酵 性 alcohol 生産性 菌株를 새로이 開發할 目的에서 다음과 같은 一漣의 實驗結果를 얻었다. S. diastaticus의 醱酵液과 S. diastaticus+S. uvarum 混合醱酵液의 風味特性등을 確認하였다. 風味成分 抽出은 methylene chloride와 diethylether를 가지고 neutral flavor fraction과 acidic flavor fraction으로 나누었고 gas chromatography를 通하여 同定 및 定量하였다. Neutral flavor fraction의 경우 S. diastaticus+S. uvarum 混合醱酵液이 S. diastaticus 醱酵液보다, ester成分中에서는 ethyl acetate와 ethyl undecanoate가 더 많았고, alcohol 成分中에서는 n-propanol과 n-butanol이 더 많았다. Acidic flavor fraction의 경우 C??~C?? fatty acid가 同定 및 定量되었는데 S. diastaticus+S. uvarum 混合醱酵液이 S. diastaticus 醱酵液보다 lauric acid, caprylic acid, capric acid 含量이 두드러지게 많았다. S. diastaticus의 glucoamylase 生産性, glucoamylase의 分離 精製, 酵素力價 그리고 酵素學的 特性에서 optimum pH는 5.0, optimum temperature는 55℃ 이었다. S. diastaticus와 S. uvarum을 母菌株로 이들 간의 protoplast fusion을 위한 基礎的인 硏究로서 두 菌株의 諸特性과 protoplast調製의 最適條件을 決定하고 protoplast의 regeneration 條件의 確立을 도모하였다.두 菌의 生育曲線에서 모두 培養開始 7~8 時間만에 對數期 中期에 到達되었으므로 protoplast 調製는 이 時期의 細胞를 쓰기로 하였다. Generation time은 S. diastaticus가 1.04, S. uvarum이 1.38 時間이었다. 細胞의 크기는 S. diastaticus 44.10?㎛³, S. uvarum 99.67㎛³로 S. uvarum이 2倍나 컸다. DNA 含量은 細胞 當 S. diastaticus 44.3fg, S. uvarum 37.6fg이었다. 30% glucose 및 soluble starch에 대한 두 菌株의 ethanol 醱酵能은 glucose에 對하여 S. uvarum 11.4%, S. diastaticus 8.9% 이었고 soluble starch에 對하여는 S. diastaticus 만이 6.9%이었다. 두 菌株는 generation time, 細胞크기 및 DNA 含量 等으로 보아 diploid strain임을 알 수 있었고, 融合株 選拔을 위한 marker 로는 Sacch. uvarum의 melibiose 資化能의 차이를 利用할 수 있음을 밝혔다. Protoplast의 調製에는 β-glucuronidase와 Zymoyase를 使用하였는데 두 酵素 反應最適條件은 β-glucuronidase는 pH 8.0에서 10% 濃度의 溶液으로, Zymolyase는 pH7.5에서 20㎛/ml의 濃度의 溶液으로 하여 모두 70分間 處理하는 것으로 決定하였으나 이 정도의 處理時間에서는 protoplast가 극히 不安定하게 되어 regeneration frequency가 떨어지는 것을 確認하였으며, 特히 Zymolyase 處理로 얻어진 protoplast의 regeneration率이 낮은 것은 Zymolyase中에 不純物로 微量 混在한 protease가 protoplast의 노출된 membrane-bound protein을 分解함으로써 protoplast를 破壞시키기 때문인 것으로 추측되었다. 融合實驗에 利用할 수 있을 정도의 regeneration frequency를 얻기 위해서는 Zymolyase를 45分間 處理하여 얻은 protoplast를 1.5%의 polyvinylpyrrolicone이 加해진 OYPD培地에서 重層法으로 展開하여 regeneration시키는 것이 좋은 것으로 판명되었다. As preliminary steps of protoplast fusion between Saccharomyces diastaticus and S. uvarum to develop a fusant of higher ethanol production from starch, characteristics of the two presumptive parent strains, optimal conditions for protoplast preparation and conditions for highrer regeneration frequency were investigated. To determine flavor characteristics of the parent strains, neutral and acidic flavor fractions were extracted from liquids fermented by S. diastaticus and S. diastaticus + S. uvarum with methylene chloride and diethly ether. The liquid by the mixed culture produced more ethly acetate, ethyl undecanoate, n-propanol, n-butanol, lauric acid, caprylic acid and capric acid than that by S. diastaticus. Glucoamylase from S. diastaticus was purified and activity, productivity, and characteristics were determined. Optimum conditions for the enzyme were pH 5.0 and 55℃. The two strains reached logarithmic phase in 7-8h during growth and the generation time was 1.04 in S. diastaticus and 1.38 in S. uvarum. Cell size and DNA content per cell of S. diastaticus were 44.10㎛³and 44.3 fg, and for S. uvarum, 99.67㎛³and 37.6fg. Ethanol productivities of S. diastaticus were 8.9% from 30% glucose and 6.9% from 30% starch and 11.4% from glucose with S. uvarum. Through determination of generation time, cell size, and DNA content per cell, both strains appeared as diploids, and differences in assimilability of melibiose and soluble starch of the two strains were selected as markers to determine the fusant. The optimal condition for protoplast formation was treatment of both strains with 10% ß-glucuronidase at pH 8.0 or 20㎍/ml Zymolyase at pH 7.5 for 70 min. While the regeneration frequencies were very low at 70min exposure to Zymolyase because of the instability of protoplasts, the yeasts treated for 45min were better for regeneration. The regeneration frequencies were also enhanced by 3-6 times when the regeration was carried out with 1.5% polyvinylpyrrolidone which stabilized protoplasts.

Protoplast-fusion에 依한 澱粉에서 Ethanol의 單段醱酵能 酵母 開發 : Ⅱ. Saccharomyces diastaticus의 呼吸缺損 變異菌株 分離와 特性 Ⅱ. Isolation and characterization of respiratory-deficient mutant (petite) from Saccharomyces

李啓瑚,徐鉉昌,申鉉坰 서울大學校 農科大學 1985 서울대농학연구지 Vol.10 No.1

포자형성률이 낮은 Saccharomyces diastaticus에 融合株 選拔의 marker를 도입하기 위한 시도로서 이 균주에 ethidium bromide를 10㎍/ml 농도로 처리하여 呼吸缺損 變異株를 얻었다. 이들 變異株는 母菌株가 쉽게 이용할 수 있는 glucerol같은 非醱酵性糖을 이용하지 못했으며, glycerol을 포함하는 최소배지에서 呼吸特性을 가진 菌株로 환원되지 않았다. Triphenyl tetrazolium chloride 染色特性, 酸素消費 速度의 측정 결과로 分離된 變異株의 呼吸缺損特性을 확인할 수 있었다. 呼吸缺損 變異株는 母菌株보다 낮은 生長率을 나타내었다. Glucose를 이용한 ethanol 발효에서 얻어진 호흡결손 변이주는 母菌株와 類似한 발효특성을 보였으나, 澱紛利用能과 醱酵는 호흡결손 변이주에서는 母菌株에 비하여 크게 감소하였다. 이 결과로 mitochondria 유전자에 대한 영향으로 澱粉 이용능이 영향을 받았음을 추측할 수 있었다. 그러나, 澱紛의 이용능과 발효능은 원형질체 융합을 통한 mitochondria의 이동이나 部分的 再組合을 통하여 회복되고 향상될 수 있다. 원형질체 형성률과 재생 특성, 원형질체의 안정성은 母菌株와 호흡결손 변이주와의 차이가 크지 않았다. 결국, 호흡결손 변이균주의 유도를 통하여 Saccharomyces diastaticus에 融合株 選拔의 maker를 有用하게 道入할 수 있음이 立證되었다. In order to introduce a suitable fusant marker for low sporulating Saccharomyces diastaticus, respiratory-deficient mutant(petite) colonies of Saccharomyces diastaticus were obtained after treatment with ethidium bromide(10㎍/ml). These colonies did not grow on non-fermentable carbon source such as glycerol that the parental cells readily utilize for growing. No revertant colonies were found on the minimal medium containing glycerol(MMG plate). The tetrazolium assay and the rate of oxygen uptake revealed the respiratory deficiency of the isolated colonies. The petite colonies showed slower growth rate than the parental cells. The results obtained for ethanol productivity of glucose showed that the petite colonies obtained are similiar to the parental strain. But the assimilation and fermentation of starch were reduced by the induction of the petite colonies. These results suggested that the uptake and the utilization of starch be affected by the damaged mitochondrial genome. But the ability to utilize and ferment starch can be recovered and enhanced by mitochondrial transfer and partial recombination through protoplast fusion. Protoplast formation, protoplast stability and regeneration rate showed no difference between parental cells and petite strain. The petite mutation proved to be useful in introducing selectable genetic marker into Saccharomyces diastaticus.

Brevibacterium sp.에 의한 글루탐酸 醱酵에 있어서 글루탐酸 脫水素 酵素의 特性

諸球煥,李啓糊 서울大學校 農科大學 1987 서울대농학연구지 Vol.12 No.1

This experiment has beencarried out to examine the activity changes of glutamate dehydrogenase(GDH) in L-glutamic acid fermentation, and to investigate the enzyme kinetics of GDH in the forward reaction and backward reaction. The used microorganism was Brevibacterium sp, which was L-glutamate producing strain. The activity changes of GDH during the culture were similar to the cell growth pattern in the biotin-sufficient media. The initial rate of backward reaction was 15 times faster than that of forward reaction. The activity of GDH was recovered by feeding additional sugar about 4 hours later in the biotin-sufficient RCM media. The optimum pH of GDH was 9.0 when the reaction was forward and 7.5 when it was backward reaction. The optimum temperature of GDH activity was 35℃. In case of backward reaction, Michaelis constant was 2.25x10?M Vmax value was 2.50D/Mg protein.min. In case of forward reaction, Km value was 4.55x10-1M and Vmax value was 2.0 0.D/mg.protein min. Km value of forward reaction was 200 times higher than that of backward reaction. This result suggested that the rate of converting substrate (L-GA) to product(α-KG) is considerably slow.

새로운 대두발효식품의 국내생산에 관한 연구 : Tempeh 제조에 관하여 On the Manufacturing of Tempeh

金栽勖,李啓瑚 서울대학교 1973 서울대학교 論文集 Vol.23 No.-

As a series of studies on the soy-bean protein and their related substances, nine samples were collected from nine places such as meju to obtain mold Rhizopus strains which fermented soy-bean food, tempeh. Tempeh, an Indonesian food produced by growing a mold Rhizopus oryzae on soy-beans has been suggested as a possible source of low cost protein for child feeding. Among these samples, total of eighteen strains were isolated by the use of dilution pour plate method. For all isolated strains primary screening of productivity of protease, lipase, amylase and useful strains with regard to enzyme productivities were identified. Optimum conditions for enzyme action of protease, lipase, amylase from selected strain Rhizopus oligosporus and isolated H-2 strains were pH 6.0 and 40℃. As the fermentation progressed, water soluble nitrogen, TCA soluble nitrogen, amino nitrogen, peptide nitrogen and soluble solids were measured about the cooked raw soy-bean, two kinds of tempeh prepared with selected different strain Rhizopus oligosporus and isolated H-2 strains. Water soluble nitrogen decreased very largely on cooked raw soy-bean, but in tempeh it increased to 51% of raw soy bean. The pH of the fermenting beans gradually rose from 5, 6 to 7.0.

고구마의 저장 및 이용에 관한 연구 : Ⅳ. 품종에 따른 저장성 , 수지함량 및 고구마칩의 가공조건 Ⅳ. Storing Capacity , Resin Content and Processing Conditions of Sweetpotato Chips of Different Varieties

이춘영,전재근,김호식,김재욱,이서래,이계호 한국농화학회 1969 Applied Biological Chemistry (Appl Biol Chem) Vol.11 No.1

Five varieties of sweetpotatoes recommended in Korea were investigated with respect to the storing rapacity, resin content and the possibility of developing sweetpotato chips as a new processed food item. The results are summarized as follows: 1) Two varieties, Suwon No. 147 and Chun-Mi were more resistant to chilling injury and soft-rot decay than other varieties. 2) The contents of resinous and polyghenolic substances were quite different depending upon the variety. 3) Sweetpotato chips of different color were made from different varieties and rapeseed oil was found to be the best as frying oil. 4) Best conditions to prepare sweetpotato chips with fresh color and proper texture were to dip slices of 1-2 ㎜ thickness in 0.25% sodium bisulfite solution at 40℃ for 30-40 minutes and to subject to deep frying in an oil bath at 150-160℃ for 2.5 to 3.5 minutes. 5) Polyethylene-cellophane film as packing material of sweetpotato chips was the best in the moisture proof and film-impact tests.

Adenine 요구변이주의 분리에 관한 연구

이춘영,김호식,김상순,이계호 한국농화학회 1969 Applied Biological Chemistry (Appl Biol Chem) Vol.11 No.1

In order to obtain amino acids and nucleic acid derivatives from adenine auxotrophic mutants of Bacillus subtilis and Escherichia coli, vitamin, nucleic acid analogue, streptomycin as well as ultraviolet light were adopted for the production of adenine auxotrophic mutants and the results showed efficient production of desired mutants. 1. Ultraviolet ray(2530 Å 2080 erg/㎟) irradiation to Bacillus subtilis and E. cola at a distance of 30 ㎝ for 80-90 sec. and for 15-20 sec. respectively induced four and eight strains of auxotrophic mutants. 2. Treatment of aminopterine(200㎍/㎖) inhibited the growth of Bacillus sulitilis significantly but a subsequent irradiation of ultraviolet light at the above mentioned conditions induced six times as much mutants as compared to the irradiation alone. In case of E. coli a similar tendency was observed with treatment of streptomycin(200 ㎍/㎖) with doubled induction rate of adenine auxotropizic mutants as compared to the irradiation alone.

한국쌀의 품질에 관한 연구

김재욱,김동연,이계호 한국농화학회 1972 Applied Biological Chemistry (Appl Biol Chem) Vol.15 No.1

The rice qualities including cooking and eating qualities were studied using recommended Korean rice varieties (20 of japonica and 3 of indica type; IR 667) which were grown at Suwon, Korea in 1971. As the result, followings were obtained. 1. Amylose contents of white rice were varied with the varieties 21.1 to 25.5% and the average was 23.0%. Three indica type varieties (IR 667) showed higher amylose contents than the other japonica type varieties except Mankyung. Among japonica type varieties, Palkum, Mankyung composed the group of the highest amyloes content and Kimmaje was the lowest. 2. Blue values were distributed in the range of 0.38 to 0.48 and the average was 0.42. IR 667 varieties showed the highest blue value among them. Among japonica type varieties, Jaegun showed the highest blue value and Sooseung, Shirogane showed successively lower values, Shin #2, Nongbaik, Palkweng, Suwon #82, Mankyung, Nonglim #25 and Nongkwang relatively lower blue values. 3. Alkali numbers were in the range of 6.0 to 7.4 and the average was 6.8. Much difference was not shown in alkali number between IR 667 group and the japonica varieties group. 4. Gelatinization temperature were ranged from 59.5 to 64.0 IR 667 varieties showed relatively higher gelatinization temperature than japonica type varieties. 5. Water uptake ratios were measured in the range of 2.67 to 2.92 and the average was 2.79. IR 667 varieties were belonged to the group of highest water uptake ratio. Among japonica type varieties Kimmaje, Suwon #82, Nonglim #29, Deungpan #5, Jaegun, Jinhung, were belonged to the group of relatively high water uptake ratio and Palkweng, Palkeum and Paldal to the relatively low water uptake ratio. 6. Expaned volums were ranged from 29.8 to 33.7 and the average was 31.8. IR 667 varieties showed higher expanded volumes than japonica type varieties. 7. Intensities of starch-iodine blue value of residual liquid indicated 0.35 to 0.58. Among them IR 667 varieties showed relatively high intensities. 8. The range of total solids in residual liquids was 0.605 to 0.810 and the average was 0.700 Much difference was not shown in total solids in residual liquid between IR 667 varieties and japonica varieties. 9. pH values of residual liquids were in the range of 6.3 to 7.3 and the average was 6.95. IR 667 varieties showed lower pH than japonica type varieties.