• 한국미생물·생명공학회지
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• 제21권2호
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• pp.125-131
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• 1993

The s-type pyocin, one kind of bacteriocins, is a bactericidal substabce of protein nature produced by certain Pseudomonas aeruginosa and is active against some other strains of the same or closely related species. Among many Pseudomonas aeruginosa strains collected from the patients at the Hospitals in Seoul and Taegu cities, some Pseudomonas aeruginosa pyocinogeny were determined by pyocin typing. As a result, Pseudomonas aeruginosa 90-2-2205 was selected as the S-type pyocin producing microorganism due to its highest antimicrobial and protease sensitivity.

• 한국식품위생안전성학회:학술대회논문집
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• 한국식품위생안전성학회 1994년도 하계 학술 심포지움
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• pp.17-22
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• 1994

Food additives are minor components which are used to enhance nutritive or sensory values, and to improve shelf life of foods. In foods, natural additives are preferred over artificial or synthetic materials because of concern on food safety. Many biotechnological techniques have been applied to the production of food additives since the biotechnology has been utilized to prodyce many flavor components such as glutamate, 5'-nucleotides, esters, 2,3-bytadione, pyrazines, terpenes, and lactones. Natural flavors, fragrances, sweetners, and colorants can be produced by plant cell culture. Many lactic acid bacteria produce bacteriocins such as nisin or diplococcin. These bacteriocins are used as safe preservatives in foods and many researches on the improvenment of bacteriocin productivity by genetic engineering are in progress.

• 한국식품위생안전성학회지
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• 제15권3호
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• pp.271-276
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• 2000

시중에서 시판되고 있는 발효비지로부터 총 58종의 균주를 분리하였으며, 그 중 starch 첨가 배지에서 투명환을 형성한 10종을 분리하였다. 이 10종의 균주를 정량적으로 amylase활성 측정을 하여 가장 큰 활성을 가진 2종의 균주를 재분리하여 공시 균주로 선정하였다 공시 균주를 동정한 결과 두 균주 모두 Bacillus sp로 동정되었으며, 각각 을 Bacillus sp. GM7330과 Bacillus sp. GM7312라고 명명하였다. 분리된 2종의 균주는 모두 5% 두부비지 용액에 glucose 3%와 yeast extract 0.15%를 첨가하여 초기 pH를 6.0으로 조정하여 30。C에서 72 hr 배양하였을 때 각각 488 units과 341 units_로 가장 큰 활성의 amylase를 생산하였다.

• 한국미생물·생명공학회지
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• 제22권2호
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• pp.143-151
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• 1994

In the course of the study on strain inprovement by protoplast fusion, Lactobacillus acidophilus 88 protoplasts production and regeneration conditions were investigated. This strain produced a bacteriocin that revealed strong inhibitory activity against various indicator strains, especially L. helveticus CNRZ 1096. Protoplasts of L. acidophilus 88 strains were very efficiently obtained by treatment with 125 $\mu $g/ml lysozyme in a protoplast forming buffer containing 20 mM N-2 hydroxy-ethtl-piperazine-N'-2-ethane-sulfonic acid(HEPES, pH 7.0) and 1M sucrose at 37$\circ $C for 30 min. Hovever, treatment with mutanolysin was not effective for the production of L. acidophilus 88 protoplasts under the same conditions. High protoplast yield was obtained form the cells at the middle to late logarithmic growth phase in the de Man, Rogosa and Sharpe(MRS) medium. Regeneration was efficiently accomplished with the MRS medium containing 10% sucrose.

• 미생물학회지
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• 제46권2호
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• pp.127-133
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• 2010

본 연구는 신생아 태변에서 분리된 Lactococcus lactis HK-9의 다양한 생리적 특성과 항균활성을 조사하기 위하여 실시하였다. 균주 HK-9을 MRS 배지에서 배양하였고, 형태 및 생리학적 특성에 대하여 조사하였으며, BIOLOG 시험과 16SrRNA 염기서열 분석을 통해 균주를 동정하였다. 그 결과 Lactococcus lactis으로 동정되었고, L. lactis HK-9로 명명하였으며, 이 균주의 계통수 분석을 통해 GenBank에 [GU936712]로 등록하였다. 배양기간에 따른 L. lactis HK-9의 생장과 중간 대사산물로서 lactic acid와 acetic acid의 생산 및 pH의 변화를 조사하였으며, 이들 유기산의 생성은 HPLC를 통하여 확인하였다. 유기산의 생성은 L. lactis HK-9의 생장에 따라 증가하는 것을 확인하였으며, 배양 60시간이 지난 후 생성된 lactic acid와 acetic acid의 농도는 각각 495.6 mM, 104.3 mM이었다. 배양 초기의 pH는 7.0이었으며 배양 기간 동안 4.1로 감소하였다. 다양한 그람양성 세균과 그람음성 세균을 대상으로 농축된 HK-9 배양상등액의 항균력을 조사하였으며, 그 결과 항균범위가 그람양성 세균에서만 나타나는 것이 관찰되었다. 농축된 배양상등액을 protease를 처리한 후 항균활성은 소멸하였으며, 상등액의 박테리오신 추정 분자의 분자량은 tricine-SDS-PAGE를 통하여 약 4 kDa으로 확인되었다.

• 한국미생물·생명공학회지
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• 제38권4호
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• pp.391-398
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• 2010

산란계에서 본 연구의 목적은 생균제(PY0.3%, PY0.5%) 를 산란계에 급여하였을 때 산란율, 산란수, 난중, 등외란, 파란율 등을 조사하기 위하여 실시하였다. 산란계에서의 사양시험은 36주령 ISA brown 산란계 300수를 공시하였으며, 처리구로는 옥수수-대두박 기초 사료구(Con; basal diet), 기초 사료구에 일반 효모 0.3%(basal diet+0.3% 일반효모), 일반 효모 0.5%(basal diet+0.5% 일반효모), 활성 효모 0.3%(basal diet+0.3% 유전자 변형 효모), 활성 효모 0.5%(basal diet+0.5% 유전자 변형 효모)를 첨가한 것으로 구성되었다. 총 13주간의 사양시험 기간 동안, 산란율, 산란수, 난중, 등 외란, 파란율 등을 연구했다. 사양시험에 이용한 닭은 각각 20수씩 3반복을 하였으며, 총 300수를 사용했다. 시험결과 시험군인 활성 효모 첨가군이 대조군에 비해서 산란율, 산란수, 난중에서 우수한 효과를 보였으며, 일반효모 첨가군에 비해서는 산란율, 산란수에 대해서는 우수하였으나 난중에서는 유의성이 없었다(p<0.05). 등외란과 파란율에서는 첨가 군에서 큰 란이 생산되는 비율이 크다 보니까 상대적으로 등 외란과 파란율이 높아진 면도 있다. 이러한 우수한 결과는 PY를 첨가함으로써 면역 기능강화와 bacteriocin의 기능과 효모에서 분비된 여러 가지 유용물질의 상호작용에서 기인된 결과로 보여 지며 이런 이유로 사료효율 개선과 병원성 미생물의 억제효과 등이 복합적으로 작용하여 상승효과로 작용했기 때문이라고 추정된다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권4호
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• pp.296-303
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• 2005

A strain named as HJ35 was isolated from the skin of sixty-five men and fourteen women for acne therapy, in order to find an effective antimicrobial agent against Propionibacterium acnes. Isolate HJ35 was identified as Enterococcus faecium based on 16 rDNA sequence and produced enterocin HJ35 having antimicrobial activities against most lactic acid bacteria, En­terococcus spp., Staphylococcus aureus, S. epidermidis, Clostridium perfringens, some bacilli, Mi­crococcus flavus, Listeria monocytogenes, L. ivanovii, Escherichia coli, Pseudomonas fluorescens and Propionibacterium acnes, in the modified well diffusion method. Especially, enterocin HJ35 showed a bactericidal activity against Propionibacterium acnes P1. The antimicrobial activity of enterocin HJ35 was disappeared completely with the use of protease XIV. But enterocin HJ35 activity is very stable at high temperature (up to $100^{\circ}C$ for 30 min), in wide range of pH (3.0${\~}$9.0), and by treatment with organic solvents. The apparent molecular mass of enterocin HJ35 was estimated to be approximately 4${\~}$4.5 kDa on detection of its bactericidal activity after SDS-PAGE. In batch fermentation of E. faecium HJ35, enterocin HJ35 was produced at the mid­log growth phase, and its maximum production was obtained up to 2,300 AU/mL at the late stationary phase. By employing fed-batch fermentation, the enhanced production of enterocin HJ35 was achieved up to 12,800 AU/mL by feeding with 10 g/L glucose or 6 g/L lactate.

• Journal of Microbiology and Biotechnology
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• 제26권5호
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• pp.975-987
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• 2016

Lactobacillus plantarum (L. plantarum) is a representative probiotic. In particular, L. plantarum is the first commensal bacterium to colonize the intestine of infants. For this reason, the initial settlement of L. plantarum can play an important role in determining an infant's health as well as their eventual health status as an adult. In addition, L. plantarum combats pathogenic infections (such as Escherichia coli (E. coli), one of the early pathogenic colonizers in an unhealthy infant gut) by secreting antimicrobial substances. The aim of this research was to determine how L. plantarum combats E. coli infection and why it is a representative probiotic in the intestine. Consequently, this research observed that E. coli releases uracil. L. plantarum specifically recognizes E. coli-derived uracil, which increases the growth rate and production of antimicrobial substance of L. plantarum. In addition, through the inhibitory activity test, this study postulates that the antimicrobial substance is a protein and can be considered a bacteriocin-like substance. Therefore, this research assumes that L. plantarum exerts its antibacterial ability by recognizing E. coli and increasing its growth rate as a result, and this phenomenon could be one of the reasons for L. plantarum settling in the intestine of infants as a beneficial bacterium.

• 한국수산과학회지
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• 제45권6호
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• pp.600-605
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• 2012

In this study, we investigated the mechanism of inhibition of pathogenic bacteria by Pediococcus pentosaceus strain SH-10 isolated from hard Clam Meretrix meretrix sikhae. When P. pentosaceus SH-10 was co-cultured in MRS broth with pathogenic bacteria, including Bacillus cereus, Listeria monocytogenes, Salmonella choleraesuis and Staphyloccus aureus, no viable pathogenic cells were detected after 18 h of incubation. However, pediocin or a pediocin-like bacteriocin was not detected in cultures of P. pentosaceus SH-10 by the agar diffusion method. Organic acids were produced in MRS broth in proportion to the incubation time of P. pentosaceus SH-10. These results indicate that P. pentosaceus SH-10 inhibited the growth of pathogenic bacteria by lowering the pH of the growth medium through the production of organic acids, including sodium lactate, sodium acetate, and sodium citrate.

• 한국축산식품학회지
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• 제33권3호
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• pp.395-402
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• 2013

Sodium chloride is used to improve various properties of processed meat products, e.g., taste, preservation, water binding capacity, texture, meat batter viscosity, safety, and flavor; however, many studies have shown that sodium chloride increases the resistance of many foodborne pathogens to heat and acid. Listeria monocytogenes has been isolated from various readyto- eat (RTE) meat and dairy products formulated with sodium chloride; therefore, the objective of this paper was to review the effects of sodium chloride on the physiological characteristics of L. monocytogenes. The exposure of L. monocytogenes to sodium chloride may increase biofilm formation on foods or food contact surfaces, virulence gene transcription, invasion of Caco-2 cells, and bacteriocin production, depending on L. monocytogenes strain and serotype as well as sodium chloride concentration. When L. monocytogenes cells were exposed to sodium chloride, their resistance to UV-C irradiation and freezing temperatures increased, but sodium chloride had no effect on their resistance to gamma irradiation. The morphological properties of L. monocytogenes, especially cell elongation and filament formation, also change in response to sodium chloride. These findings indicate that sodium chloride affects various physiological responses of L. monocytogenes and thus, the effect of sodium chloride on L. monocytogenes in RTE meat and dairy products needs to be considered with respect to food safety. Moreover, further studies of microbial risk assessment should be conducted to suggest an appropriate sodium chloride concentration in animal origin foods.