• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.293.2-293.2
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• 2013

구조색에 기반을 둔 반사형 디스플레이는 낮은 전력 소모와 쉬운 제조 과정뿐만 아니라 후광 없이 작동이 가능한 장점으로 인해 최근 많은 주목을 받고 있다. 하지만 기술적으로 다양한 색체 구현이 어려워 현재까지는 많이 응용되고 있지는 않다. 이에 본 연구에서 우리는 바이러스(M13-박테리오파지)를 기반으로 한 신개념 컬러 디스플레이를 개발하고자 한다. 우리가 개발하고자 하는 컬러디스플레이는 자가 조립방법으로 만들어진 나노 구조체로 형성되어 있으며, 간단한 실험 조건 조절을 통해 다양한 색깔 구현을 할 수 있다. 특히, MEMS 공정으로 자체 제작한 Micro Heater의 온도 조절을 통해 자가 조립된 나노 구조체의 간격 주기를 조절 하면, 기존에 형성된 색을 원하는대로 자유롭게 바꿀 수 있다. 우리가 개발하고자하는 생체 재료 기반 컬러 소자는 차세대 디스플레이의 또 다른 새로운 시도가 되리라 생각한다.

• Journal of Life Science
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• v.19 no.7
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• pp.994-1002
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• 2009

A bacteriocin-producing bacterium identified as Bacillus licheniformis was isolated from soybean sauce. Antibacterial activity was confirmed by paper disc diffusion method, using Micrococcus luteus as a test organism. The bacteriocin also showed antibacterial activities against Bacillus sphaericus, Lactobacillus bulgaricus, Lactobacillus planiarum, Paenibacillus polymyxa, and Pediococcus dextrinicus. Optimal culture conditions for the production of bacteriocin was attained by growing the cells in an MRS medium at a pH of 6.5~ 7.0 and a temperature of 37$^\circ$C for 36$\sim$48 hr. Solvents such as chloroform, ethanol, acetone, and acetonitrile had little effect on bacteriocin activity. However, about 50% of bacteriocin activity diminished with treatment of methanol and isopropanol at the final concentration of 50% at 25$^\circ$C for 1 hr. It was stable against a pH variation range from 3.0 and 7.0, but the activity reduced to 50% at a pH range from 9.0 to 11.0. It's activity was not affected by heat treatment at 100$^\circ$C for 30 min and 50% of activity was retained after heat treatment at 100$^\circ$C for 60 min, showing high thermostability. The bacteriocin was purified to a homogeneity through ammonium sulfate precipitation, SP-Sepharose ion-exchange chromatography, and reverse-phase high-performance liquid chromatography (HPLC). The entire purification protocol led to a 75-fold increase in specific activity and a 13.5% yield of bacteriocin activity. The molecular weight of purified bacteriocin was estimated to be about 2.5 kDa by tricine-SDS-PAGE.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.288-299
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• 2015

Lactobacillus brevis BK11 obtained from Baikkimchi was selected to study the effects of culture medium, initial pH, atmosphere composition, incubation temperature and time, and prebiotics on growth and production of antimicrobial substances. Growth and antimicrobial substances production of L. brevis BK11 were significantly higher in MRS broth than in BHI or M17 broth. The production of cell mass, lactic acid, and bacteriocin by BK11 strain was at maximum in MRS broth adjusted to pH 6.0. Aerobic and microaerobic conditions were favored cell growth and antimicrobial substances production than anaerobic condition. Biomass and lactic acid production and antimicrobial substances activity of BK 11 were significantly better at 30 and $37^{\circ}C$ than at $25^{\circ}C$. Growth of the strain BK11 entered the stationary growth stage at 24 h after inoculation, and decreased after 36 h. Antimicrobial activities of cell-free culture supernatant and bacteriocin solution were highest when cultured in MRS broth with an initial pH 6.0 for 24-30 h at $37^{\circ}C$. In addition, the highest cell number and lactic acid and bacteriocin production were recorded in the presence of 1 and 2% (w/v) fructooligosaccharide (FOS), however, inulin and raffinose did not affect biological and physicochemical characteristics and antimicrobial activities of L. brevis BK11 cultures. According to these results, production of antimicrobial substances by L. brevis KB11 was closely associated with cell density. Under optimal conditions for antimicrobial substances production, L. brevis BK11 effectively inhibited the growth of Helicobacter pylori ATCC 43504.

• Food Science and Preservation
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• v.6 no.4
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• pp.514-520
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• 1999

Changes in pH, titratable acidity, CO$_2$production, reducing sugar, and lactic acid bacteria of fresh kimchi juice supplemented with combinations of 3 lactic acid bacteria and germanium(Ge)-132 or fructooligosaccharide(FO) during fermentation at 30$^{\circ}C$ were investigated to assess the potential for extending the shelf life and enhancing the functional properties in kimchi. In kimchi juice containing Ge-132, sample(I) (inoculated with a mixture of bacteriocin-producing SNF-13 strain and E. faecium) exhibited that the amounts of organic acid and evolved CO$_2$gas were lower than those of the other starter samples(II-IV). The growth of lactic acid bacteria naturally present in kimchi juice, particularly Lb. plantarum and Leu. mesentroides, may be inhibited due to competition of the isolated SNF-13 strain and E. faecium by Ge-132. During fermentation of kimchi juice containing FO sugar, the contents of organic acid and evolved CO$_2$gas On juice broth with 4 starters were predominantly higher than those of control and Ge-132 groups, and then the growth of lactic acid bacteria originated from kimchi ingredients was thought to be markedly accelerated. Our results indicated that functional properties like the extension of shelf life and increase of biological activity in kimchi were enhanced by adding Ge-132 and bacterium-producing lactic acid bacterium, which were resistant to organic acid and stimulated by Ge-132.

• Food Engineering Progress
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• v.13 no.1
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• pp.64-69
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• 2009

From the 25 fresh fruits and vegetable products, 1,250 isolates grown on MRS agar media were screened for the inhibitory activity on the growth of Escherichia coli 0157:H7, Listeria monocytogenes, and Bacillus cereus as well as Lactobacillus plantarum, L. casei, and Lactococcus lactis subsp. lactis. Among them, 607 isolates (49% of total isolates) from 23 different foods produced growth inhibitory activity on the E. coli 0157:H7, L. monocytogenes, or B. cereus. When these isolates were screened for the inhibitory activity on the growth of L. plantarum, L. casei, and Lactococcus lactis subsp., 24 isolates (3% of total isolates) from 7 food samples showed bacteriocin-like activity. These isolates had typical physiological characteristics of lactic acid bacteria, which indicated these isolates were strains of lactic acid bacteria. The inhibitor from 3 out of 24 revealed as nicin. From the RAPD-PCR profiles, 24 strains was classified and it was also indicated that most of the strains isolated from same produce showed similar phylogenetic profile.

• Journal of Food Hygiene and Safety
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• v.37 no.2
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• pp.97-106
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• 2022

Listeria monocytogenes (L. monocytogenes) is one of gram-positive foodborne pathogens with a very high fatality rate. Unlike most foodborne pathogens, L. monocytogenes is capable of growing at low temperatures, such as in refrigerated foods. Thus, various physical and chemical prevention methods are used in the manufacturing, processing and distribution of food. However, there are limitations to the methods such as possible changes to the food quality and the consumer awareness of synthetic preservatives. Thus, the aim of this study was to evaluate the anti-listeria activity of lactic acid bacteria (LAB) isolated from kimchi and characterize the bacteriocin produced by Lactococcuslactis which is one of isolated strains from kimchi. The analysis on the anti-listeria activity of a total of 36 species (Lactobacillus, Weissella, Lactobacillus, and Lactococcus) isolated from kimchi by the agar overlay method revealed that L. lactis NJ 1-10 and NJ 1-16 had the highest anti-listeria activity. For quantitatively analysis on the anti-listeria activity, NJ 1-10 and NJ 1-16 were co-cultured with L. monocytogenes in Brain Heat Infusion (BHI) broth, respectively. As a result, L. monocytogenes was reduced by 3.0 log CFU/mL in 20 h, lowering the number of bacteria to below the detection limit. Both LAB strains showed anti-listeria activity against 24 serotypes of L. monocytogenes, although the sizes of clear zone was slightly different. No clear zone was observed when the supernatants of both LAB cultures were treated with proteinase-K, indicating that their anti-listerial activities might be due to the production of bacteriocins. Heat stability of the partially purified bacteriocins of NJ 1-10 and NJ 1-16 was relatively stable at 60℃ and 80℃. Yet, their anti-listeria activities were completely lost by 60 min of treatment at 100℃ and 15 min of treatment at 121℃. The analysis on the pH stability showed that their anti-listeria activities were the most stable at pH 4.01, and decreased with the increasing pH value, yet, was not completely lost. Partially purified bacteriocins showed relatively stable anti-listeria activities in acetone, ethanol, and methanol, but their activities were reduced after chloroform treatment, yet was not completely lost. Conclusively, this study revealed that the bacteriocins produced by NJ 1-10 and NJ 1-16 effectively reduced L. monocytogenes, and that they were relatively stable against heat, pH, and organic solvents, therefore implying their potential as a natural antibacterial substance for controlling L. monocytogenes in food.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.707-710
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• 2005

The antimicrobial activities of extracts from some of natural products and bacteriocins produced from lactic acid bacteria such as L. mesenteroides, L. citreum and P. pentosaceus have been investigated with using disc diffusion assay, challenge method and minimum inhibitory concentration method. The bacteriocin substances produced from L. mesenteroides, L. citreum and P, pentosaceus have shown strong antimicrobial activities against E. coli, S. aureus, P. aerugionosa, and B. subtillis while the extracts from phenonip and sandal wood have shown strong antimicrobial activities only against C. albicans. The bacteriocins produced from L. mesenteroides, L. citreum and P. pentosaceus could be a promising preservatives for cosmetics, pharmaceutical products and foods in future.

• Microbiology and Biotechnology Letters
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• v.29 no.1
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• pp.50-55
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• 2001

A new bacteriocin produced by Bacillus subtilis cx1, was partially purified and characterized. The bactericoin from B. subtilis cx1 was stable in the range of pH 2.5-9.5. B. subtilis csx1 retained its antimicrobial activity to long-term exposure at $-20^{\circ}C$ and $-70^{\circ}C$. However, B. subtilis cx1 was inactivated completely within 15 min over $60^{\circ}C$ and lost 50% of its antimicrobial activity within 15 min at $50^{\circ}C$, B. subtilis cx1 was inactivated by protease, trypsin, proteinase K and carboxypeptidase, which indi-cates its protein nature. Direct detection of the antimicrobial activity on Tricine -SDS-PAGE suggested an apparent molecular mass of about 9,500 dalton.

• Korean Journal of Microbiology
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• v.55 no.3
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• pp.258-267
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• 2019

The purpose of this study was to investigate the effect of lactic acid bacteria (LAB) on the growth and biogenic amines (BA) formation of Enterobacter aerogenes CIH05 in skim milk and soymilk. Lactobacillus acidophilus GK20, Lactobacillus paracasei GK74, and Lactobacillus plantarum GK81 isolated from mustard kimchi did not produce BA in the decarboxylation broth. L. paracasei GK74 exhibited the highest cell viability and antimicrobial compounds producing ability in fermented skim milk and soymilk samples, while the lowest producer was L. plantarum GK81. The production yield of lactic acid, hydrogen peroxide, and bacteriocin was dependent on the species of Lactobacillus and the type of culture medium. As LAB the number of viable cells of E. aerogenes CIH05 were higher in skim milk than in soymilk. When mixed culture with L. acidophilus GK20 and L. paracasei GK74 and treated with bacteriocin solution (300 AU/ml) obtained from these strains in milk media, the cell growth and cadaverine and histamine contents of E. aerogenes CIH05 were significantly (P < 0.05) lower than the respective values in control sample.

• Korean Journal of Veterinary Research
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• v.50 no.4
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• pp.297-302
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• 2010

This study was conducted to investigate the effects of feeding probiotics (gene modified yeast) on the growth performances in pigs. In pigs, this study investigated the effects of dietary probiotics which contained antibacterial probiotics (OR-7, bacteriocin, gene modified yeast) on growth performances and feed efficiency in pig farm. A total of 150 pigs were studied. The treatments are probiotics yeast (PY) 0.3% (basal diet + 0.3% plasmid modified probiotics), PY 0.5% (basal diet + 0.5% plasmid modified probiotics), yeast (Y) 0.3% (basal diet + 0.3% probiotics), Y 0.5% (basal diet + 0.5% probiotics) and control (basal diet). Weight gain, feed intake and feed efficiency were periodically recorded for 90 days. The treatment group trended higher weight gain, feed intake and feed efficiency than control. And, the PY group trended higher weight gain, feed intake and feed efficiency than Y group.