• KSBB Journal
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• v.18 no.3
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• pp.243-247
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• 2003

The microbial immobilization media with curdlan and activated carbon which has great immobilization capacity has been developed. Characteristics of porosity and mechanical strength of this support media are dependent on manufacturing method. The support media showed the best cell immobilization performance when the ratio of curdlan and activated carbon was 30 g/L to 6 g/L in this study. The immobilization of iron-oxidizing bacteria on the supporting particles was photographed with a scanning electron microscope. Since cell concentration on the surface of supporting particle increased with the reaction time, the iron oxidation rate also increased.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.249-256
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• 1992

Potato juice was found out to have a strong inhibition activity on the growth of Clostridium perf;nngens during work of foodstuffs for the improvement of human intestinal microflora. The anti-bacterial activity of the precipitated protein obtained from the potato juice in 70% ammonium sulfate solution was stable at the range of pH 4 to 10, whereas it was lost by a heat treatment at $60^{\circ}C$ for 10 min. The minimal inhibitory concentration of the precipitated protein on the growth of C1. Pefingens was about 0.2 mg/ml. The potato protein also suppressed the growth of C1. butyrincm and Eubacterium iimosum, while it showed a promoting effect for the growth of Bifdobacterium bifidum, Bif: animalis, Lactobacillus plantarum and Lact. acidophitus. The potato protein was further purified by CM-Sepharose ion exchange column chromatography, Sephadex G-150 gel filtration column chromatography and SDS-polyacrylarnide gel electrophoresis. The purified protein(kCp) was proved to be a glycoprotein by PAS staining and its molecular weight was about 38.7 kd.

• Microbiology and Biotechnology Letters
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• v.44 no.1
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• pp.98-105
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• 2016

The presence of bacterial strains showing antagonistic activity to common pathogens found in a variety of fermented foods in Korea was explored. A bacterium inhibiting the growth of pathogens such as Aspergillus terreus (KCTC6178), A. flavus (KCTC6984), Staphylococcus aureus (KCCM12214), Escherichia coli O157:H7 (KCCM40406), Bacillus cereus (KCTC1012), Cryptococcus neoformans (ATCC208821), Salmonella typhimurium (ATCC19430), and Listeria monocytogenes (KCTC3569) was isolated from Makgeolli, a Korean traditional rice wine. The strain showing high antipathogenic activity was identified as B. amyloliquefaciens based on the nucleotide sequence of the 16S ribosomal RNA gene. Compared with B. amyloliquefaciens KCTC1660, whose genome has been sequenced, the isolate exhibited significantly low activities of starch-degrading enzymes and high resistance to high temperature and low pH.

• Korean Journal of Microbiology
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• v.33 no.3
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• pp.170-174
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• 1997

In order to design a novel synthetic peptide with improved fungicidal activity but low hemolytic activity, a hybrid peptide, cecropin A(l-8)-magainin 2(1-12), and its analogue peptides were synthesized by the solid phase method. Antifungal and hemolytic activities of the synthetic peptides were assessed by the growth inhibition against Trichosporon beigelii and the cell membrane lysis against human red hlood cells, respectively. Analogue 2 in which Lys at position 12 in cecropin A(1-8)-magainin 2(1-12) was substituted with Ala showed most potent antifungal activity (MIC: 2.5.$\mu$g/ml) with minimal hemolytic activity (0.5% hemolysis at the (200.$\mu$g/ml peptide). This peptide (A2), therefore, could be useful as a model for further designing potent antifungal peptides without cytotoxicity.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.65-65
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• 2018

복분자(Rubus coreanus Miquel)는 anthocyanin, phenolic acid, tannin, flavonoid, stilbenoid와 같은 생리활성물질이 풍부하게 존재하는 것으로 보고되었으며 항염증, 항암활성, 항산화효과 등 다양한 생리활성에 대한 효능이 있어 건강식품으로써 애용되고 있을 뿐만 아니라 약용성 건강보조식품 등으로 각광받고 있다. 생물전환(Bioconversion)은 미생물 또는 효소의 생물학적 촉매 기반 천연소재의 생리활성 물질기능성, 생체이용률, 안전성을 증대시키기 위한 방안으로 많은 연구가 진행되고 있으며 아울러 식품, 의약품, 화장품 등 다양한 분야에서 활성화 되고 있다. 본 연구는 불가사리 발효액으로부터 유산균을 분리하였으며, 유전학적 특성을 확인하기 위하여 16S rDNA 염기서열을 분석하였다. 전북 고창에서 수확된 복분자를 분말상태로 유산균과 발효공정을 수행하였으며, 복분자의 최적 추출조건 선정과 발효공정 전 후의 활성을 관찰하였다. 발효공정 후 추출물의 기능성 평가를 진행하기 위하여 DPPH radical scavenging activity, total polyphenol 함량을 확인하여 항산화 효능 및 유효성분 함량을 평가하였다. 또한 대식세포인 Raw 264.7을 사용하여 MTT assay, Nitric oxide (NO) 생성 억제 효능을 확인하여 세포독성 및 항염증 활성을 평가하였다. 실험결과, 발효기간이 다른 불가사리 비료발효액으로부터 16 종의 다양한 균주를 확보하였으며, 생물전환 공정에 유용 균주를 선정하기 위하여 복분자 분말의 발효공정을 실시한 결과 3 종의 유산균 처리군에서 무처리군 대비 DPPH radical 소거능 및 polyphenol 함량이 증가됨을 확인하였다. 그 중 가장 우수한 활성을 나타내는 균주를 16S rDNA 염기서열 분석한 결과 Lactobacillus coryniformis A6-4로 확인되었으며, 발효공정 후 항산화 활성은 무처리군 대비 약 115%, polyphenol의 함량은 무처리군 대비 약 121%로 증가됨을 확인되었다. 또한 발효공정 후 독성활성이 감소되는 경향을 확인되었으며, 항염증 활성이 유의적으로 증가됨을 확인하였다.

• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.307-312
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• 1989

Strain No.77-AG-567 showed antifungal activity against Pyricularia oryzas and Sphaerotheca fuliginea. In the process of purification of active component this strain was found to produce blasticidin S together with another antibiotic. This compound was identified as being acetoxycyc-heximide, also referred to as E-73, by UV and $^1$H NMR spectral data. Identification of this strain led us to conclude that strain No.77-AG-567 is most probably be Streptomyces atratus. It showed different characteristics from S. atbutus, so far known to produce both blasticidin S and acetoxycycloheximide. Particularly worthy of note was the difference in spore surface. In addition, acetoxycycloheximide has been known to have activity only against yeast and tumor cells but we found that it also has activity against Pyricularia oryzae and Sphasrotheca fuliginea.

• Korean Journal of Microbiology
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• v.27 no.3
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• pp.245-249
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• 1989

Extracellular proteases of Bacillus licheniformis were partially purified using ammonium sulfate fractionation and Sephadex G-75 gel filtration chromatography. The partial purification permited the weparation of two different protease activities, type I and type II. Protease type I is an enzyme with rather high protealytic activity toward dasein and was highly susceptible to organofluoride and EDTA inhibitions. It showed maximal proteolytic activity at pH 7.5 and was rapidly denatured at $71^{\circ}C$. Protease type II is a protease with relatively lower proteolytic activity than the type I. It was also inhibited by 10mM of EDTA and 1mM of PMSF by 30 min incubation. The enzyme showed maximal activity at pH 8.0 and was denatured relatively slowly at $71^{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.20 no.6
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• pp.699-703
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• 1992

An oriental drug, named NP-S, traditionally used as a therapeutic agent for hepatitis B was characterized by separating into volatile and non-volatile fractions. The volatile fraction contained ammonia as determined by ammonia kit and eight peaks when it was analyzed by gas chromatography that are not identified yet. The elemental analysis showed that the non-volatile fraction contained 15.5% carbon, 4.8% hydrogen, 11% nitrogen, and 10% sulfur along with a few trace elements such as Cl, Si, Mg and Zn. NP-S contained 6.7% peptide, 0.3% free amino acids such as Lys, Pro, Arg, lie, Tyr, Phe, His, Thr and Ser and 0.1% inorganic phosphate. The drug showed antimicrobial activity against Salmonella typhimurium, StaPhylococcus aureus and Candida albieans and also had antioxidant activity when thiobarbituric acid reacting substances(TBARS) method was applied.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.346-351
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• 2002

A bacterium producing the neutral pretense was isolated from soil, and was identified as Bacillus sp. DS-1 by 16S rRNA sequence comparison and biochemical determinations. The production of protease from Bacillus sp. DS-1 was increased 20% and 30% by the additions of 1% glucose and 1% yeast extract, respectively. The optimum pH and temperature for the protease activity were pH 7.0 and 55$^{\circ}C$. Bacillus sp. DS-1 produced a metalloprotease as a major protease in culture medium, since the pretense activity in culture supernatant was inhibited by the presence of 1 mM EDTA significantly.

• Microbiology and Biotechnology Letters
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• v.18 no.4
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• pp.383-389
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• 1990

During the cultivation of Penkillium uerrmulosum in the media containing cellobiose octaacetate (COA), avicel, or KC-flock as an inducer and as a sole carbon source for 21 days, cellulolytic activity and SDS-PAGE pattern of proteins in the culture broth were investigated. Protein concentration and cellulolytic activity were highest in the COA medium. As cultivation period was increased, protein content and avicel hydrolytic activity of culture broth were increased as similar extent but neither $\beta$-glucosidase nor CMC hydrolytic activity was correlated to protein content. When crude proteins from the culture broth were separated on DEAE column by HPLC, distribution of avicel-hydrolytic activities were well correlated with that of major proteins. From those results it was suggested that three major proteins having 60 K, 68 K, and 76 K of Mr. were avicel-hydrolytic enzymes.