• 미생물학회지
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• 제38권4호
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• pp.254-259
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• 2002

저온에서 최적 생육을 보이는 저온성 균주를 남극해양에서 분리하여 생화학적 특성 및 165 rRNA 염기서열로부터 Shewanella sp.에 속하는 균주로 동정하고 Shewanella sp. L93으로명명하였다. 본 균주에서 생산되는 저온성 세포외 단백질 분해 효소(extracellular protease)를 ammonium sulfate precipitation, High-Q column chromatography, 일차 gel permeation chromatography, BioScale Q2 ion exchange chromatography 및 gel permeation chromatography를 통하여 purification fold 19.3, yield 0.7 %로 정제하였고 그 특성을 조사하였다.

• Journal of Microbiology and Biotechnology
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• 제15권4호
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• pp.689-693
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• 2005

Bacillus sp. JB-99, when grown in a chemically defined medium containing lactose as a carbon source, yielded 3,860 U/ml extracellular $\beta$-mannanase, which was high compared to other examined carbon sources. Among the nitrogen sources, yeast extract enhanced the enzyme activity. The enzyme production was growth-associated. The enzyme was optimally active at $65^{\circ}C$, pH 10, and had a half-life of 190 min at $65^{\circ}C$. N-Bromosuccinamide and $AgNO_3,\;CuSO_4$, and $HgCl_2$ strongly inhibited the enzyme, whereas $Ca^{2+}$ stimulated the enzyme activity. The $\alpha$-galactosidase enzyme production was not found in any of the enzyme assays.

• Mycobiology
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• 제42권2호
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• pp.109-113
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• 2014

During a survey of marine fungi from the waters surrounding Jeju Island, Korea, several Penicillium strains were isolated from seawater and marine sponges. Based on morphological characteristics and phylogenetic analyses of the internal transcribed spacer and RNA polymerase subunit II, four strains were identified as Penicillium antarcticum, a fungus that, to the best of our knowledge, had not been previously reported in Korea. Here, we provide detailed descriptions of the morphological characteristics and extracellular enzyme activities of the four strains.

• Journal of Microbiology and Biotechnology
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• 제21권5호
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• pp.483-493
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• 2011

An acid phosphatase (HppA) activated by $NH_4Cl$ was purified 192- and 34-fold from the periplasmic and membrane fractions of Helicobacter pylori, respectively. SDS-polyacrylamide gel electrophoresis revealed that HppA from the latter appears to be several kilodaltons larger in molecular mass than from the former by about 24 kDa. Under acidic conditions (pH${\leq}$4.5), the enzyme activity was entirely dependent on the presence of certain mono- and/or divalent metal cations (e.g., $K^+$,$ NH_4{^+}$, and/or $Ni^{2+}$). In particular, $Ni^{2+}$ appeared to lower the enzyme's $K_m$ for the substrates, without changing $V_{max}$. The purified enzyme showed differential specificity against nucleotide substrates with pH; for example, the enzyme hydrolyzed adenosine nucleotides more rapidly at pH 5.5 than at pH 6.0, and vice versa for CTP or TTP. Analyses of the enzyme's N-terminal sequence and of an $HppA^-$ H. pylori mutant revealed that the purified enzyme is identical to rHppA, a cloned H. pylori class C acid phosphatase, and shown to be the sole bacterial 5'-nucleotidase uniquely activated by $NH_4Cl$. In contrast to wild type, $HppA^-$ H. pylori cells grew more slowly. Strikingly, they imported $Mg^{2+}$ at a markedly lowered rate, but assimilated urea rapidly, with a subsequent increase in extracellular pH. Moreover, mutant cells were much more sensitive to extracellular potassium ions, as well as to metronidazole, omeprazole, or thiophenol, with considerably lowered MIC values, than wild-type cells. From these data, we suggest that the role of the acid phosphatase HppA in H. pylori may extend beyond 5'-nucleotidase function to include cation-flux as well as pH regulation on the cell envelope.

• 미생물학회지
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• 제51권1호
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• pp.75-80
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• 2015

동해에서 분리된 Pseudoalteromonas donghaensis HJ51는 체외분비 단백질 분해효소를 생산하는 신종 미생물로 보고되었다. 체외 단백질 분해효소의 특성과 최적 생산 조건을 결정하기 위해 crude supernatant을 사용하여 단백질 분해효소의 최적 활성 온도와 pH를 조사한 결과 $40^{\circ}C$와 pH 7.5-10.5이었으며, pH 11에서도 88%의 높은 상대적인 효소 활성을 나타내었다. 효소의 금속 요구성을 조사한 결과, $Fe^{3+}$를 10 mM로 첨가하였을 때 최대 효소활성 증가를 보였다. 최대의 효소생산 조건을 탐색한 결과, 기본배지인 PY-ASW (peptone 0.5%, yeast extract 1.0%, artificial seawater)에 탄소원을 첨가하지 않는 것이 가장 높았으며, 질소원으로는 peptone 보다 beef extract, tryptone, casmino acids을 각각 첨가했을 때 활성이 21, 7, 4% 증가하였다. 이러한 결과를 종합해 볼 때 P. donghaensis HJ51이 생산하는 효소는 알칼리성 pH 환경 및 저온환경에서 활성이 필요한 분야에 응용이 가능할 것으로 사료된다.

• KSBB Journal
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• 제21권2호
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• pp.85-89
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• 2006

F. trogii ATCC 200800으로부터 원형질체 분리를 통해 단일균주들을 선별하였으며, 선별된 균주들의 고체배양 및 agar plug assay를 통해 효소생산을 위한 균주를 대량 선별하였다. Agar plug assay를 통해 4일 동안 100여종 이상의 균주를 동시에 배양, 분석이 가능하였으며, 염료분해환을 형성하지 않은 균주는 액체배양 확인 결과 MnP의 생산이 거의 일어나지 않는 것으로 나타났다. 이러한 방법으로 선별된 균주를 이용하여 UV 돌연변이를 통해 모균주로부터 유전적 변이를 유도해 새로운 균주선별을 시도하였으며, 이로부터 모균주와 비교하여 효소생산성이 향상되고 안정성이 증대된 균주를 선별할 수 있었다. 모균주와 선별된 균주의 명확한 유전적 차이를 규명하기보다는 배양시 형태학적 특성이 상이함을 확인하였다. 또한, 선별된 균주를 이용하여 배양액내에 다양한 종류의 inducer를 첨가에 따라 효소생산에 미치는 영향을 확인하였다. 과량의 inducer 물질이 첨가될 경우, 균체성장은 물론 효소생산성도 크게 떨어졌으며, 균체성장이 어느 정도 이루어진 상태 즉, 이차대사가 이루어지는 시점에서 inducer를 첨가할 경우 그 효율이 최대였으며, 동시에 inducer를 첨가할 경우 보다 미량씩 일정량을 나누어 주입할 경우 효소생산에 더 유리한 것으로 나타났다.

• Journal of Microbiology
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• 제40권1호
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• pp.26-32
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• 2002

From the culture supernatant of the psychrotrophic strain of Bacillus amyloliquefaciens an extracellular serine protease was purified to apparent homogeneity by successive purification steps using QAE-Sephadex, SP-Sephadex and Sephacryl S-100 column chromatography. The pretense is monomeric, with a relative molecular mass of 23,000. It is inhibited by the serine protease inhibitor phenylmethylsulfonyl fluoride, but not by EDTA. The enzyme is most active at pH 9-10 and at $45^{\circ}C$, although it is unstable at $60^{\circ}C$.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2006년도 제47회 학술심포지움 및 추계국제학술대회
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• pp.28.1-28.1
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• 2006

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.628-635
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• 2001

Recombinant E. coli DH5$\alpha$ harboring a dextransucrase gene (dsrB742) produced an extracellular dextransucrase in a 2% sucrose medium. The enzyme was purified by DEAE-Sepharose and Phenyl-Sepharose column chromatographies upto a 142.97-fold purification with a 11.11% recovery to near homogeneity. The enzyme had a calculated molecular mass of 168.6 kDa, which was in good agreement with the activity band of 170 kDa on a nondenaturing SDS-PAGE. An expression plasmid was constructed by inserting the dsrB742 into a pRSET expression vector. The activity after expression in E. coli BL21(DE3)pLysS increased about 6.7-fold compared to the extracellular dextransucrase from L. mesenteroides B-742CB. The expressed and purified enzyme from the clone showed similar biochemical properties (acceptor reaction, size of active dextransucrase, optimum pH, and temperature) to B-742CB dextransucrase, however, the ability to synthesize ${\alpha}$-(1$\rightarrow$3) branching decreased in comparison to that of L. mesenteroides B-742CB dextransucrase.

• 한국미생물·생명공학회지
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• 제28권6호
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• pp.329-333
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• 2000

Alkaline bacterium producing a high pro-tease activity at low temperature was isolated by using enrichment culture from soil samples and identified as Bacil-lus sp. WRD-1 Cell growth was maximal at 10 hours and the optimal initial pH and culture time of culture condition for enzyme production was pH 7 and 10 hours, respectively. Temperature range of high enzyme activity were $10~40^{\circ}C$. The optimal pH and temperature for the enzyme activity were pH9 and $30^{\circ}C$.