• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.8
• /
• pp.1251-1257
• /
• 2005

This study was carried out to investigate characteristics of acetic acid bacteria for persimmon vinegar fermen-tation. Acetic acid bacteria were isolated from statically fermented vinegar. Microscopically the cells appeared as non-motile and non-flagellated, preferentially occuring in pairs. Isolated strains were able to grow in the presence of acetic acid, ethanol, and glucose. Four of them produced 2-ketogluconic acid but did not produce 5-ketogluconic acid. The four strains isolated from statically fermented vinegar were considered to be grouped into Acetobacter. The strains were inoculated into persimmon juice for persimmon vinegar fermentation. They produced acetic acid in the range of 5.25$\∼$5.68$\%$.

• Journal of the Korean Institute of Gas
• /
• v.24 no.1
• /
• pp.17-22
• /
• 2020

Light Naphtha is distillated from crude oil unit and separated into the methane, ethylene and propylene by boiling point difference in sequence. This separation is conducted using a series of binary-like columns. This separation method is known that the energy consumed in the reboiler is used to separate the heaviest components and most of this energy is discarded as vapor condensation in the overhead cooler. In this study, the first two columns of the separation process are replaced with the Petlyuk column. A structural design was exercised by the stage computation with ideal tray efficiency in equilibrium condition. Compared with the performance of a conventional system of 3-column model, The design outcome shows that the procedure is simple and efficient because the composition of the liquid component in the column tray was designed to be similar to the equilibrium distillation curve. The performance of the new process indicates that an energy saving of 12.1% is obtained and the cost savings of 44 million won per day based on gross domestic product is reduced under same total number of trays and the initial investment cost is saved.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.42 no.4
• /
• pp.359-366
• /
• 2016

Exosome, a small vesicle secreted from cells, has diverse functions depending on cell origins and tissue types and plays a important role in cell viability and intercellular communication. Recently, many researchers have demonstrated the use of exosomes for the treatment of cancers and immune diseases, and the development of diagnostic biomarker. However, the secretion mechanism of exosome from skin cell and its physiological functions in skin remain unclear. Thus, this study aimed to explore whether keratinocyte-derived exosome affects proliferation and migration in HaCaTs. Exosomes were isolated from HaCaTs by ExoQuick-TC and then boiled or unbolied. Boiled and unboiled exosome induced proliferation in HaCaTs in a dose-dependant manner ($0.1{\sim}20{\mu}g/mL$), respectively. Boiled and unboiled exosome at concentration of $20{\mu}g/mL$ increased proliferation level in HaCaTs by $186.96{\pm}3.87%$ and $193.48{\pm}10.48%$ compared with control group. Unboiled exosome stimulated migration in HaCaTs in a dose-dependent manner ($0.1{\sim}20{\mu}g/mL$), which reached a maxium at concentration of $20{\mu}g/mL$ ($179.39{\pm}4.89%$ of control), but boiled exosome did not affect HaCaT migration. In addition, unboiled exosome ($0.1{\sim}20{\mu}g/mL$) dose-dependently stimulated sprout outgrowth in HaCats. These results demonstrate that in exosome from HaCaTs, heat-stable components such as lipid may induce HaCaT proliferation and heat-unstable components such as protein may stimulate migration and sprout outgrowth in HaCaTs, thereby leading to reepithelialization and skin-wound healing activities. It is concluded that exosomes from HaCaTs may be used as cosmetic materials.

• Korean Journal of Microbiology
• /
• v.28 no.2
• /
• pp.174-179
• /
• 1990

In order to overproduce L-phenylalanine, various kind of regulatory mutants were isolated from parental Escherichia coli K-12. MWEC 83 Producing 7.4g/l of L-phenylalanine has been derived as a tyrosine and tryptophan double auxotrophic mutant. To produce L-phenylalanine without adding L-tyrosine and L-tryptophan, revertant strain MWEC 101 was isolated from MWEC 83. Further various analogues and valine resistant mutants were isolated from MWEC 101. MWEC 101-5 was the most excellent strain that produced 17.9g/l of L-phenylalanine after having been cultivated for 54 hours in 15% glucose medium. It was disclosed that activities of rate-limiting enzymes including chorismate mutase and prephenate dehydratase in MWEC 101-5 were desensitized to 2mM L-phenylalanine in the enzyme reaction mixture and that activities level of 3-deoxy-D-arabino-heptulosonic acid-7-phosphate synthase and prephenate dehydratase were increased more than 20 times over those of the parental strain.

• Microbiology and Biotechnology Letters
• /
• v.31 no.3
• /
• pp.271-276
• /
• 2003

Bacillus amyloliquefaciens D4, which produces a strongly fibrinolytic enzyme, was isolated from Chungkook-Jang, a traditional Korean soybean-fermented food. B. amyloliquefaciens D4 was mutated with N-methyl-N-nitro-N-nitrosoguanidine (MNNG) to yield a series of mutants with increasing levels of fibrinolytic enzyme production. After mutation, a mutant D4-7 was obtained with fibrinolytic activity about eight times stronger than the parent strain. The fibrinolytic activity of B. amyloliquefaciens D4-7, reached a maximum, when the producer was cultivated in 2% Isolated Soy Protein (ISP) broth for 48 h at $37^{\circ}C$. Compared to commercial fibrinolytic enzymes, the cell-free culture supernatant of B. amyloliquefaciens D4-7 showed stronger activity than plasmin and streptokinase. The optimum temperature and pH were $50^{\circ}C$ and 10.0 and thermostability was increased by the addition of glycerol, glucose, and NaCl.

• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.660-664
• /
• 2000

To clone genes related UK-58,852 production, genomic DNA of strain Actinodura roseorufa was used for the construction of genomic library using pOJ446 cosmid vector. The genomic library was screened rising dehydratase PCR product and eryA gene as a DNA hybridization probe. pHD54 was isolated, which contained an approximately 35kb of inserted DNA. BamHI, SmaI and sonicater fragments hybridized to eryA probe. All of pHD54 BgmHI, SmaI and sonicater fragments were subcloned into pGEM7 and some fragments which hybridized to eryA probe were sequenced. The nucleotide sequence was analysed using BLAST program. The sequence identities were observed in KS,AT, KR, ER and PKS loading domains. Also oxidoreductase showed similarity to rifamycin module10, and dTDP-D-glucose 4,6 dehydratase and TDP-D-glucose synthase involved in biosynthesis of sugar showed similarity to Streptomyces argillaceus.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2010.05a
• /
• pp.29.2-29.2
• /
• 2010

최근 박막형 LED 및 박막형 태양전지등의 기존 마이크로 소자들의 효율향상을 위한 개선으로 나노구조를 이용한 나노소자 제작이 관심을 받고 있다. 이는 가능성으로만 여겨져왔던 나노기술이 기존 박막형 소자에서 포화된 효율상향 접근방식의 한계에 따른 것으로 생각되며, 나아가 나노기술로 제작된 나노소자가 우리 생활을 채우게 될 날이 얼마남지 않은 것을 의미한다. 특히, 디스플레이 소자에서의 나노기술은 더욱 더 중요시 되고 있다. 그로 인해 투명성과 우수한 광전기적 특성을 지닌 산화물 반도체와 그 나노구조 대한 관심이 날로 높아지고 있으며, 그 가운데 산화아연계(ZnO, MgZnO등) 나노구조를 이용한 나노소자 제작이 많이 연구되고 있다. 산화아연은 c축으로 우선 배향성을 가지는 우르짜이트 구조로써, 나노선 성장이 다른 산화물에 비해 용이하고 그 물리적, 화학적 특성이 안정 우수하다. 이러한 산화아연 나노선 제작법 가운데, 유기금속화학기상증착법은 다른 성장법에 비해 결정학적 광학적 특성이 우수하고 성장속도가 빨라 고품질 나노선 성장에 용이한 장비로 각광받고 있다. 하지만 bottom-up 공정을 기반으로 한 나노소자제작에서 몇 가지 문제점을 가지고 있다. 1) 수직형 대면적 성장, 2) 나노선 밀도 조절의 어려움, 3) 기판과의 계면층에 자발적으로 생성되는 계면층의 제거, 4) 고온성장시 precursor의 증발 문제 등이 그것이다. 이러한 문제점을 해결하기 위해 산화아연 나노구조 성장 시, 마그네슘(Mg)을 도입하여, 각 원소의 조성 차이에 따라 기판 표면에 30nm 두께 미만의 상분리층(단결정+비정질층)을 자발적으로 형성시켰다. 성장이 진행됨에 따라, 아연이 rich한 단결정 층에서는 나노선이 선택적으로 성장하게 하였고, 마그네슘이 rich한 비정질 층에서는 성장이 이루어지지 않게 하였다. 따라서 산화아연이 증발되는 온도영역에서 10nm 이하 직경을 가지는 나노선을 자발적으로 계면층 없이 수직 성장하였다. 또한, 표면의 단결정, 비정질의 사이즈를 Mg 유량으로 적절히 조절한 결과, 산화아연계 나노월 구조성장이 가능하였다.

• Korean Journal of Microbiology
• /
• v.36 no.2
• /
• pp.103-108
• /
• 2000

We have cloned and analyzed cDNA coding for non-virion (NV) protein of the m V - P R T The NV gene contained 336 bp open readmg frame and encoded a protein of 11 1 amino acids with a molecular weight of 13.2 kDa. The deduced amino acid sequence of NV of IHNVPRT was found to be 90-95% identical to those of foreign isolates of IHNV. These results indicate that NV gene of the MNV is highly conserved among &ifferent strains of THNV Northern blot analyses revealed that the levels of NV gene expression were strongly elevated after 20 h post-infection. In order to identify the role of NV in the replication of MNV in fish cells, IHNVinfected cells were treated with antisense oligonucleotides. While IHNV-PRT exposed to glycoprotein (G) antisense oligonucleotide showed severely reduced growth, the growth of virus exposed to NV antisense oligonucleotide was not affected by NV antisense oligonucleotide, which suggests that NV is not essential for replication of IHNV in fish cells.

• Korean Journal of Food Science and Technology
• /
• v.47 no.1
• /
• pp.126-131
• /
• 2015

Pathogenic Escherichia coli is recognized as an important cause of diarrhea, hemorrhagic colitis and hemolytic-uremic syndrome worldwide. This study was conducted to investigate the prevalence E. coli contamination in the Korean traditional food bibimbap. E. coli were isolated from 84 of 1142 (7.3%) bibimbap investigated from 2005 to 2011. Antibiotic resistance profiling demonstrated that 6 of the 84 isolates (7.2%) showed multiple drug resistance. Fifteen virulence genes specific for pathogenic E. coli such as Shiga toxin-producing E. coli (STEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), and enteroaggregative E. coli (EAEC) were examined by multiplex PCR for mixed bacterial cultures derived from bibimbap samples. The EPEC virulence gene (ent) was detected in 5 strains (5.9%), while ETEC, EAEC, and EIEC were not detected. STEC serotypes O103 (1.2%), O91 (1.2%), and O128 (6.0%) were found, but other serogroups such as O26, O157, O145, O111 and O121 were not detecded. Automated Repetitive-Sequence-Based PCR analysis showed different patterns.

• Resources Recycling
• /
• v.27 no.5
• /
• pp.69-76
• /
• 2018

For the purpose of optimizing the counter current extraction process for separation of [Sm] and [Pr, Nd] group in hydrochloric acid solution using Cyanex 572 as an extractant, the theory of Xu Guangxian was derived for calculating the optimized extraction factors. From the basic batch test result, the separation factor of [Sm]/[Pr, Nd] was 14.59 at pH 1.75 in extraction process and 14.61 at 0.01 M HCl in scrubbing process. The process parameters can be calculated using a theory of optimum extraction ratio. From the result of calculation, the total extraction and scrubbing stage numbers at counter current process were 11 and for maintain extraction ratio the flow rate ratio of feed solution, solvent solution, scrubbing solution was 6.25 : 1.74 : 5.80 using 0.1 M HCl.