• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.519.2-519
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• 1986

고온 호알카리성 Bacillus K-17의 xylanase유전자의 구조해명과 대량 생산 균주를 개발하기 위채 Bacillus K-17의 염색체를 pER 322를 사용하여 E. coli에 형질전환시켜 xylanase 활성을 나타내는 형질전환체를 얻었다. 이 형질전환체에서 hybrid plasmid를 분리하여 제한효소로 mapping하였고 이 유전자가 Bacillus K-17유래인가를 hybridization에 의해 확인하였다. Recombinant plasmid pAX 1113은 5.1kb HindIII 절편을 가졌으며 BgIII site가 두곳, ECoRI과 pst site가 한곳이었으며 효소를 정제한 결과 Bacillus K-17이 생산하는 두 가지 xylanase중에서 xylanase I과 동일하였다.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1979.04a
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• pp.115.1-115
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• 1979

Streptomyces속 균주가 생산하는 Phospholieste-rase를 몇가지 방법에 의하여 정제하여 그 성질을 조사 검토했다. 1) Sephadex G-50 및 DEAE-Cellulose Column Chromatography에 의하여 300배 정제하였으며 그 수율은 3.8%이었다. 2) b-PNPP을 기질로 해서 정제한 본 효소의 성질을 검토한 결과 본효소의 활성발현에 $Ca^{++}$ 이온이 필요했으며 $Ca^{++}$ 이온은 이 효소의 열안정성에도 도움을 주었다. 또 이효소의 최적작용 pH는 8.0부근이었으며 최적작용온도는 $50^{\circ}C$ 부근이었고 b-PNPP 을 기질로 한 Km 치 는 1.11mg/mι 이었다.

• Korean Journal of Microbiology
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• v.47 no.3
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• pp.255-262
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• 2011

Six protein-degrading bacteria were isolated from digestive organ of Harmonia axyridis. These isolates were categorized as Staphylococcus sciuri subsp. sciuri (3 strains), Bacillus subtilis (1 strain), and Bacillus thuringiensis (2 strains) by 16S rRNA gene sequence analysis. The Staphylococcus sp. CB2-3 was selected as a protease-producing bacterium which showed the highest protease activity of 58.5 U/ml at the pH 5.0 medium. The optimal pH and temperature of protease activity were pH 5.0 and $40^{\circ}C$, respectively. This acid protease had a relatively high stability of 80% between $30-50^{\circ}C$ at broad temperature range. The opimal medium compositions of carbon, nitrogen and mineral source for cell growth and protease activity were investigated. When sorbitol (0.5%) was used as carbon source, enzyme activity was increased about 2 times than that of the basal medium. When skim milk (0.5%) was used as nitrogen source, activity was increased about 2.5 times than that of the control. Cell growth and enzyme activity were increased by mineral source such as KCl, $K_2HPO_4$, $FeSO_4$, but was completely inhibited by divalent ions such as $Co^{2+}$, $Zn^{2+}$, $Mn^{2+}$, $Cu^{2+}$.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.330-336
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• 2011

Bacterial strains exhibiting fibrinolytic activity were screened from traditional Korean soybean sauce. The Fibrinolytic activities of the various isolated microorganism were further examined and the superior strain YJ11-21 was selected for further analyses. Gene sequence analysis of 16S rDNA of the YJ11-21 strain revealed Bacillus licheniformis. Optimal culture conditions were investigated in order to maximize the production of the fibrinolytic enzyme by YJ11-21. Amongst the carbon sources tested, glucose was the most effective for enzyme production and amongst the nitrogen sources tested, yeast extract was seen to be the most effective. A one percent addition of NaCl to the medium resulted in the highest fibrinolytic activity. Interestingly, a 10% addition of NaCl resulted in a high activity together with a high cell growth rate. Therefore, YJ11-21 is speculated of being a halotolerant. The optimum pH and temperature for enzyme production were a pH of 9.0 and $30^{\circ}C$, respectively.

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.241-246
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• 2002

A gene coding for endo-$\beta$-1,3-1,4-glucanase of Bacillus circulans was subcloned into Escherichia coli Ml5 using pQE30 as an expression vector. Endo-$\beta$-1,3-1,4-glucanase produced by the recombinant expression plas-mid pLQ43 was intactly purified to a single protein through a nickel-nitrilotriacetic acid (Ni-NTA) metal-affinity chromatography method. The molecular mass of the purified enzyme was estimated to be 28 kDa by SDS-PAGE. The optimum pH and temperature of the enzyme activity were pH 6.8 and $60^{\circ}C$, respectively. This enzyme was fairly stable in the pH ranging 5.5~7.5 and at the temperatures lower than $55^{\circ}C$. The enzyme appeared to be sensitive to most of the metal ions, especially to $Hg^{2＋$, and also to methanol, ethanol, isopropanol or 1-butanol at a concentration of 10%(v/v).

• Korean Journal of Microbiology
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• v.42 no.2
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• pp.131-134
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• 2006

The culture conditions for the enhanced mycelial of Clavicorona pyxidata DGUM 29005 were investigated. The optimal temperature and pH for the mycelial growth were $24^{\circ}C$ and 5.0, respectively. It was shown that trehalose was the best supplement of carbon sources in Czapek-Dox medium as a minimal medium for enhanced mycelial growth. In general, inorganic nitrogen sources were better than organic ones for mycelial growth. Calcium nitrate was the best out of the inorganic nitrogen test. The appropriate phosphorous and vitamin were $Na_2HPO_4$ and p-aminobenzoic acid, respectively. After the mycelial of C. pyxidata DGUM 29005 was cultivated at $24^{\circ}C$ for 20 days in MEM broth(pH 5.0), the specific activities of both exomycelial and endomycelial enzymes were determined. Among the exomycelial enzyme assayed, the specific activity of laccase was much higher than those of other enzymes. However, little or no enzyme activities of ${\alpha}$-amylase, chitinase, lipase and pretense were found.

• Korean Journal of Microbiology
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• v.26 no.4
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• pp.368-374
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• 1988

Enzymological proprties of an extracellular cytosine deaminase from Bacellus polymyxa YL 38-3 were investigated. The extracellular enzyme was very stable, and optimum pH and temperature for the enzyme activity were found to be near pH 6.0 in 0.2M potassium phosphate buffer and at $30^{\circ}C$, respectively. 5-Fluorocytosine was converyed to 5-fluorouracil by the enzyme, but 5-methylcytosine was not to thymine by it. The enzyme activity was completely inhibited by some heavy metal ion such as 1mM of $Cd^{2-}$ and $Hg^{2+}$, and by 1mM of p-chloromercuribenzoate, respectively. The enzyme activity was inactivated about 75% by 1mM of o-phenanthroline and monoiodoacetate. But the enzyme activity was stimulated up to 200% by 1mM of 2-mercaptoethanol.

• Microbiology and Biotechnology Letters
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• v.20 no.6
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• pp.681-686
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• 1992

In the conversion of D.L-2-amino-$\Delta^2$-thiazoline-4-carboxylic acid(D,L-ATC) to L-cysteine using Pseudomonas sp. CU6. the effects of surfactants on whole cells and the stabilities of cellfree enzyme solution and continuous reactor packed with immobilized whole cells were investigated. The enzymatic reaction was little accomplished by whole cells without adding surfactants, whereas it was well carried out with SDS or Triton X-loo comparable to the case using cell-free enzyme solution. Enzyme activity of the cell-free solution was lost by 50% after 7 hours of storage at $30^{\circ}C$, but not at all under an anaerobic condition by sparging nitrogen gas. On the other hand. effect of nitrogen gas did not appear in a continuous reactor using immobilized whole cells, and hydroxylamine, an inhibitor of L-cysteine desulfhydrase, lowered the enzyme stability.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.33-43
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• 2013

A bacterium producing a fibrinolytic enzyme was isolated from Cheonggukjang. The bacterium was identified as a strain of Bacillus amyloliquefaciens by 16S rDNA analysis and designated as B. amyloliquefaciens HC188. The optimum culture medium appeared to be one containing 0.5% (w/v) maltose and 0.5% (w/v) soytone. Bacterial growth in the optimal medium at $37^{\circ}C$ reached the stationary phase after 27 h of incubation and the fibrinolytic enzyme showed optimum activity at 24 h. The enzyme was purified by 20-80% ammonium sulfate precipitation, CM Sepharose fast flow ion exchange chromatography, and Sephacryl S-200HR column chromatography. Its specific activity was 38359.3 units/mg protein and the yield was 5.5% of the total activity of the crude extracts. The molecular weight was 24.7 kDa and the amino acids of the N-terminal sequence were AQSVPYGVSQIKAPA. The fibrinolytic enzyme activity had an optimum temperature of $40^{\circ}C$ and an optimum pH of 8.0, and the enzyme was stable in the ranges $20-40^{\circ}C$ and pH 6.0-8.0. Enzyme activity was increased by $Ca^{2+}$ and $Co^{2+}$ but inhibited by $Cu^{2+}$, EDTA, and PMSF. It is suggested that the purified enzyme is a metallo-serine protease.

• Journal of Life Science
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• v.22 no.6
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• pp.751-759
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• 2012

Microbulbifer sp. was used to acquire the degrading products from Ecklonia cava (DPEC) and the products were investigated to determine the physiological activities. Firstly, 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity and superoxide dismutase (SOD) assay were about 84.1% and 89.6% at 2.5 mg/ml, respectively. In addition, nitrite scavenging ability was shown to be 56.3% at 0.5 mg/ml on pH 1.2. ${\alpha}$-Glucosidase inhibitory activity was increased in a dose-dependent manner and was about 58.7% at 2.5 mg/ml. To determine the influence of DPEC on alcohol metabolism, the generating activity of reduced-nicotinamide adenine dinucleotide (NADH) by alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) were measured. Facilitating rates of ADH and ALDH activities by DPEC were 123.3% and 215.2% at 2.5 mg/ml, respectively. For analyses of anti-wrinkling and whitening effects, its elastase and tyrosinase inhibitory activities were measured and were about 73.1% and 42.2% at 2.5 mg/ml, respectively. These results indicated that DPEC has valuable biological attributes owing to its antioxidant, nitrite scavenging, and alcohol metabolizing activities and ${\alpha}$-glucosidase, elastase, and tyrosinase inhibitory activities.