• 생명과학회지
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• 제16권4호
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• pp.653-658
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• 2006

사과 겹무늬썩음병균이(Botryosphaeria dothidea) 생성하는 세포벽 분해효소인 endopolygalaturonase를 억제하는 polygalacturonase-inhibiting protein (PGIP)를 사과 과실로부터 분리하였다. 분리되어진 사과 PGIP는 사과 겹무늬썩음병균이 생성하는 PG에 대하여 혼합형의 저해를 나타내었다. PGIP의 반응 최적온도는 $40^{\circ}C$이며 최적 pH는 5.0이었다. 이 효소는 $60^{\circ}C$까지는 비교적 안정하였으나 $70^{\circ}C$에서는 효소의 활성이 완전히 억제되었으며 pH 4.0에서 8.0까지는 안정하였다. PGIP는 $K^+$, $Cu^{2+}$, $Mg^{2+}$, $Ca^{2+}$ 과 $Zn^{2+}$ 등의 금속이온과 SDS 그리고 CDTA에 의해 효소의 활성이 저해되었다.

• Journal of Microbiology and Biotechnology
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• 제34권2호
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• pp.436-456
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• 2024

Several thermostable proteases have been identified, yet only a handful have undergone the processes of cloning, comprehensive characterization, and full exploitation in various industrial applications. Our primary aim in this study was to clone a thermostable alkaline protease from a thermophilic bacterium and assess its potential for use in various industries. The research involved the amplification of the SpSKF4 protease gene, a thermostable alkaline serine protease obtained from the Geobacillus thermoglucosidasius SKF4 bacterium through polymerase chain reaction (PCR). The purified recombinant SpSKF4 protease was characterized, followed by evaluation of its possible industrial applications. The analysis of the gene sequence revealed an open reading frame (ORF) consisting of 1,206 bp, coding for a protein containing 401 amino acids. The cloned gene was expressed in Escherichia coli. The molecular weight of the enzyme was measured at 28 kDa using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The partially purified enzyme has its highest activity at a pH of 10 and a temperature of 80℃. In addition, the enzyme showed a half-life of 15 h at 80℃, and there was a 60% increase in its activity at 10 mM Ca²⁺ concentration. The activity of the protease was completely inhibited (100%) by phenylmethylsulfonyl fluoride (PMSF); however, the addition of sodium dodecyl sulfate (SDS) resulted in a 20% increase in activity. The enzyme was also stable in various organic solvents and in certain commercial detergents. Furthermore, the enzyme exhibited strong potential for industrial use, particularly as a detergent additive and for facilitating the recovery of silver from X-ray film.

• Journal of Microbiology and Biotechnology
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• 제22권8호
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• pp.1092-1100
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• 2012

Ten Bacillus strains with antimicrobial activities were isolated from Cheonggukjang produced at different parts in Korea. They all inhibited Listeria monocytogenes ATCC 19111 and nine inhibited Bacillus cereus ATCC 14579. Four isolates (W42, H27, SKE 12, and K21) showing strong inhibiting activities were identified as B. subtilis. B. subtilis W42 was the most inhibiting strain. The antimicrobial activity of culture supernatant from B. subtilis W42 was destroyed completely by proteinase K treatment, indicating that a bacteriocin was the responsible agent. The bacteriocin, Bac W42, was most stable at pH 7 and stable between pH 3-6 and 8-9. Bac W42 was stable up to $80^{\circ}C$. BHI (brain heart infusion) and TSB (tryptic soy broth) were the best media for the activity (320 AU/ml) followed by LB (160 AU/ml). Bac W42 was partially purified by column chromatographies. The specific activity was increased from 1,151.2 AU/ml to 9,043.5 AU/ml and the final yield was 26.3%. Bac W42 was 5.4 kDa in size as determined by SDS-PAGE. Bac W42 showed bactericidal activity against L. monocytogenes ATCC 19111.

• Journal of Microbiology and Biotechnology
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• 제7권6호
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• pp.409-416
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• 1997

Leuconostoc sp. LAB145-3A isolated from kimchi produced a bacteriocin which was active against food pathogens, such as Listeria monocytogenes, Enterococcus faecalis, and E. faecium. Bacteriocin production occurred during the early exponential phase of growth and was stable upto the late stationary phase of growth. Optimum conditions for bacteriocin production were $37^{\circ}C$ with an initial pH of 7.0. The bacteriocin of LAB145-3A was sensitive to proteases, but stable for solvents, pH change and heat treatment. It was stable even at autoclaving temperature for 15 min. The bacteriocin exhibited a bactericidal mode of action against Lactobacillus curvatus LAB170-12. The bacteriocin produced by Leuconostoc sp. LAB145-3A was purified by CM-cellulose cation exchange column chromatography and Sephadex G-50 gel filtration. The purification resulted in an approximate 10,000-fold increase in the specific activity. Approximately 4% of the initial activity was recovered. Purified bacteriocin exhibited a single band on the SDS-PAGE with an apparent molecular weight of 4,400 daltons. This bacteriocin was named leucocin K. Leuconostoc sp. LAB145-3A had two residential plasmids with molecular sizes of 23 kb and 48 kb. A comparison of plasmid profiles between LAB145-3A and its mutants revealed that the 23 kb plasmid (pCA23) was responsible for bacteriocin production and immunity to the bacteriocin in Leuconostoc sp. LAB145-3A.

• 한국미생물·생명공학회지
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• 제48권3호
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• pp.358-365
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• 2020

An organic solvent- and bleach-stable protease-producing strain was isolated from a polluted river water sample and identified as Aeromonas veronii OB3 on the basis of biochemical properties (API 20E) and 16S rRNA sequence analysis. The strain was found to hyper-produce alkaline protease when cultivated on fish waste powder-based medium (HVSP, 4080 U/ml). The biochemical properties and compatibility of OB3 with several detergents and additives were studied. Maximum activity was observed at pH 9.0 and 60℃. The crude protease displayed outstanding stability to the investigated surfactants and oxidants, such as Tween 80, Triton X-100, and H₂O₂, and almost 36% residual activity when incubated with 1% SDS. Remarkably, the enzyme demonstrated considerable compatibility with commercial detergents, retaining more than 100% of its activity with Ariel and Tide (1 h, 40℃). Moreover, washing performance of Tide significantly improved by the supplementation of small amounts of OB3 crude protease. These properties suggest the potential use of this alkaline protease as a bio-additive in the detergent industry and other biotechnological processes such as peptide synthesis.

• 한국식품위생안전성학회지
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• 제31권6호
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• pp.445-450
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• 2016

본 연구에서는 돈지육 및 돈육 조직 내에 열안정성 수용성 단백질의 존재 여부를 확인하고 항체 생산에 있어 항원으로의 사용 가능 여부를 확인하고자 하였다. 이를 위해 돈지육 및 돈육을 생(raw) 시료와 조리된(cooked) 시료로 구분하여 비열처리 및 열처리법으로 단백질을 추출한 후 단백질 존재여부를 단백질 정량과 SDS-PAGE로 확인하였다. 그 결과 돈지육과 돈육 모두 생 시료를 비열처리법으로 추출한 시료의 경우 25~100 kDa 사이의 다양한 단백질이 확인된 반면 시료를 가열하거나 추출 시 열처리를 한 경우 돈지육에는 100 kDa 이상의 단백질과 30 kDa 및 15 kDa 이하의 일부 단백질이, 돈육에는 100 kDa 이상과 30 kDa 이하의 단백질이 확인되어 돈지육과 돈육에 열안정성 수용성 단백질이 존재하는 것으로 확인되었다. 이들 열안정성 수용성 단백질을 마우스에 면역 후 항혈청 역가를 측정한 결과 면역한 모든 마우스에서 높은 역가를 나타내었고, 생산된 혈청은 돈지육과 돈육에 각각 특이적인 반응성을 보인 반면 다른 축육과 지방육에 대해서는 반응성이 상대적으로 낮았다. 이러한 연구결과를 볼 때 돈지육 및 돈육에 존재하는 열안정성 수용성 단백질이 돈지육과 돈육에 특이적으로 반응하는 항체를 개발하는데 유용한 마커로서 활용이 가능하며, 열안정성 수용성 단백질에 대한 항체개발은 열처리된 축육 가공품 중 돈지육 및 돈육의 분석에도 매우 유용하게 활용할 수 있을 것으로 판단된다.

• Journal of Microbiology
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• 제37권2호
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• pp.80-85
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• 1999

The purification system of glucoamylase (glucan 1,4-${\alpha}$-glucosidase, EC 3. 2. 1. 3), some characteristics of the purified enzyme and hydrolysis rate of various raw starch were investigated through several experiments. The enzyme was produced on a solid, uncooked wheat bran medium of Aspergillus oryzae NR 3-6 isolated from traditional Korean Nuruk. The enzyme was homogeneously purified 6.8-fold with an overall yield of 28.3% by the criteria of disc- and SDS-polyacrylamide gel electrophoresis. The molecular weight was estimated to be 48 kDa by SDS-PAGE. The optimum temperature and pH were 55$^{\circ}C$ and 4.0, respectively. The enzyme was stable at a pH range of 3.0∼10.0 and below 45$^{\circ}C$. Enzyme activity was inhibited about 27% by 1mM Hg2+. The hydrolysis rate of raw wheat starch was shown to be 17.5-fold faster than the hydrolysis rate of soluble starch. The purified enzyme was identified as glucoamylase because the product of soluble starch by the purified enzyme was mainly glucose by thin layer chromatography.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2989-2994
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• 2007

Gas hydrates are ice-like crystalline compounds that form under low temperature and elevated pressure conditions. Although hydrate formation can pose serious flow-assurance problems in the gas pipelines or facilities, gas hydrates present a novel means for natural gas storage and transportation with potential applications in a wide variety of areas. An important property of hydrates that makes them attractive for use in gas storage and transportation is their very high gas-to-solid ratio. In addition to the high gas content, gas hydrates are remarkably stable. The main barrier to development of gas hydrate technology is the lack of an effective method to mass produce gas hydrate in solid form. The first objective of this study is investigating the characteristics of gas hydrate formation related to several factors such as pressure, temperature, water-to-storage volume ratio, concentration of SDS, heat transfer and whether stirred or not respectively. And the second objective is clarifying the relation between the formation efficiency and each factor in order to find the proper way or direction to improve the formation performance.

• 한국균학회지
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• 제32권2호
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• pp.125-129
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• 2004

섬유소분해효소(CMCase)를 산업적으로 이용하기 위한 기초자료를 제공하고자 섬유소분해능이 우수한 L. japonicus로부터 CMCase를 분리 정제하였다. L. japonicus의 배양액으로부터 4단계를 거쳐 분자량이 42 kDa인 CMCase를 분리 정제하였다. 이 효소는 pH 6.0에서 최적의 활성을 보여주는 acidic CMCase로서 $30^{\circ}C$에서 최대 활성을 나타냈다. EDTA에 의해 활성이 저해되는 것으로 보아 metalloenzyme으로 추정되며, SDS에 의해 저해되는 것으로 보아 S-S기를 갖고 있는 효소로 판단된다. $Al_{2}(SO_{4})_{3}$와 $BaCl_{2}$에서는 효소 활성이 높았으나 그 이외의 금속염에서는 효소 활성이 낮았다.

• Applied Biological Chemistry
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• 제46권4호
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• pp.385-390
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• 2003

미국자리공(Phytolacca americana L.) 뿌리에서 항균 펩타이드를 분리하여 PAMP-r로 명명 하였다. 분리는 DEAE-cellulose, sephadex G-75, Mono S, Resource RPC등을 거쳐 이루어 졌으며 최종산물은 15% SDS-PAGE 에서 약 4,900 Da의 분자량을 보였다. PAMP-r는 광범위한 항균활성을 나타냈으며 온도와 pH변화에도 높은 안정성을 보였다. 항균활성은 $80^{\circ}C$에서 30분동안 유지될 뿐만 아니라 pH도 3.0의 산성에서부터 pH 8.0의 알카리에 이르기까지 광범위한 범위 안에서 안정하게 나타났다.