• Biotechnology and Bioprocess Engineering:BBE
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• 제9권1호
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• pp.17-22
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• 2004

A bacterial strain WJ-98 found to produce active extracellular keratinase was isolated from the soil of a poultry factory. It was identified as Paracoccus sp. based on its 16S rRNA sequence analysis, morphological and physiological characteristics. The optimal culture conditions for the production of keratinase by Paracoccus sp. WJ-98 were investigated. The optimal medium composition for keratinase production was determined to be 1.0% keratin, 0.05% urea and NaCl, 0.03% K$_2$HPO$_4$, 0.04% KH$_2$PO$_4$, and 0.01% MgCl$_2$$.$6H$_2$O. Optimal initial pH and temperature for the production of keratinase were 7.5 and 37$^{\circ}C$, respectively. The maximum keratinase production of 90 U/mL was reached after 84 h of cultivation under the optimal culturing conditions. The keratinase from Paracoccus sp. WJ-98 was partially purified from a culture broth by using ammonium sulfate precipitation, ion-exchange chromatography on DEAE-cellulose, followed by gel filtration chromatography on Sephadex G-75. Optimum pH and temperature for the enzyme reaction were pH 6.8 and 50$^{\circ}C$, respectively and the enzymes were stable in the pH range from 6.0 to 8.0 and below 50$^{\circ}C$. The enzyme activity was significantly inhibited by EDTA, Zn$\^$2+/ and Hg$\^$2+/. Inquiry into the characteristics of keratinase production from these bacteria may yield useful agricultural feed processing applications.

• 한국식품영양과학회지
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• 제31권1호
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• pp.50-56
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• 2002

달팽이 내장을 마쇄, 추출, 염석 및 투석 후 얻은 조효소액을 두 번의 이온교환 크로마토그래피 및 두 번의 겔여과 크로마토그래피를 거쳐 최종적으로 얻은 $\beta$-galactosidase의 비활성도는 18.8 units/mg protein이었고, 정제도는 31.3%배, 수율은 20.8%이었다. $\beta$-Gallactosidase의 분자량을 측정하기 위해 겔 여과와 전기영동을 실시한 결과, native molecular weight가 약 144,000으로, SDS-PAGE 결과, 약 72,000으로 나타나 이 효소는 동일한 polypeptide로 구성된 dime로 추측되었으며, 등전점은 pI 4.1이었다. $\beta$-Galactosidase의 최적 pH와 온도는 각각 pH 3.0과 6$0^{\circ}C$로 측정되었으며, pH 2.0~8.0에서 80%이상의 효소 활성을 나타내었고, 온도 30~5$0^{\circ}C$에서 안정되었다. 모든 금속이온과 fructose, glucose, galactose, maltose 및 xylose는 $\beta$-galactosidase의 저해제로 작용하였다.

• 공업화학
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• 제7권5호
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• pp.832-842
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• 1996

성질이 서로 다른 그물 구조형 이온교환수지인 Amberlyst-15, Amberlyst-15(wet)와 Amberlyst XN-1010을 가지고 고정층 상압 유통식 반응장치에서 옥탄가 향상제인 TAME 합성반응을 행하였다. Amberlyst-15가 Amberlyst-15(wet)와 Amberlyst XN-1010에 비해 활성이 좋았는데 그 이유는 겔형 미세입자 내부 활성점의 반응참여 정도가 크기 때문으로 생각되며, TAME 합성반응의 최적 조건들은, 반응온도=$135^{\circ}C$, 반응물 몰비(MeOH/I.A.A.)=1.0~4.0, W/F=2.0~4.0 gr.-cat. hr/gr.-mole일 때이었다. X-ray 회절 분석결과 $2{\theta}=20$에서 styrene divinyl benzene이 가교결합을 나타냈으며, DSC 분석결과 열적 안정성의 순서로는 Amberlyst-15, Amberlyst-15(wet) 및 Amberlyst XN-1010이였다. 본 실험에서 구한 TAME 합성의 겉보기 활성화 에너지 값은 Amberlyst-15:Ea=12.36 kcal/mole, Amberlyst-15(wet):Ea=12.46 kcal/mole 및 Amberlyst XN-1010:Ea=14.72 kcal/mole이였다.

• 멤브레인
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• 제20권1호
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• pp.1-7
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• 2010

원자전달 라디칼 중합을 이용하여 poly(styrene sulfonic acid) 47 wt%를 가진 poly(vinylidene fluoride-co-chlorotrifluoroethylene)-g-poly(styrene sulfonic acid) (P(VDF-co-CTFE)-g-PSSA) 가지형 공중합체를 합성하였다. 티타늄 아이소프로폭사이드(TTIP)와 가지형 공중합체를 졸-겔 공정을 통하여 $TiO_2$/가지형 공중합체 복합막을 제조하였다. TTIP는 가지형 공중합체의 친수성을 가진 PSSA 영역에만 선택적으로 결합하였으며 그곳에 $TiO_2$ 나노 입자가 형성되어 성장하였다. 이와 같은 결과를 적외선과 자외선 분광학으로 확인할 수 있다. 함수량과 이온 교환 능력 (IEC)는 TTIP의 함량에 따라 감소하였고 이것은 막이 가진 술폰산의 수가 감소하기 때문이었다. TTIP가 5 중량%일 때, 막의 기계적 강도는 증가하고 수소이온 전도도도 유지되었다.

• 한국재료학회지
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• 제10권5호
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• pp.360-363
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• 2000

다양한 Zr/Ti 비율을 갖고 있는 강유전체 PZT박막을 졸-겔 법으로 증착하였고 상부 백금전극의 제조방법과 열처리온도의 변화에 따라 강유전체 특성을 측정하여 이력곡선의 변형 원인을 조사하였다. Pt/PZT/Pt 캐패시터는 상부 백금전극을 반응성 이온 식각(RIE) 하는 과정에서 생성된 dc plasma 전압에 의하여 양의 방향으로 분극되었고 도메인 계면에 포획된 전하에 의해 내부전장이 발생되었다. PZT 박막은 sputtering으로 상부전극을 증착하는 과정에서 이력곡선의 중간에 잘룩하게 되는 시효현상이 관찰되었다. 상부전극을 제작한 후 열처리는 포획된 전하흫 제거시켜 양호한 이력곡선 특성을 되찾게 하였다. Zr/Ti 비율이 감소함에 따라 내부전장이 증가하였으며 내부전장이 없어지는 열처리온도가 증가하였다.

• 한국균학회지
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• 제27권2호통권89호
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• pp.100-106
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• 1999

Agrocybe cylindracea의 배양방법별 균사체 및 다당류 생산수율비교 실험에서는 모두 진탕배양이 효과적이었다. 다당류의 정제는 조단백다당류를 이용하여 DEAE-cellulose column에 의한 1차 정제를 행하였고, 최종으로 Sepharose 2B를 이용한 2차 정제를 실시하여 최종적으로 균사체내다당류(ACIPDG, ACIPAG)와 균사체외다당류(ACEPDG, ACEPAG)를 얻었다. ACEPDG는 총당 75.8%, ACEPAG는 총당 65.4%를 함유하였으며, ACIPDG는 총당 89.2%, ACIPAG는 총당 54.2%의 조성을 보였다. 다당류 분획물들의 분자량을 측정한 결과, 모두 10만이 넘는 거대분자로 ACEPDG 300KDa에서 ACIPAG 600KDa까지 나타났다. 다당류의 조성을 HPLC로 분석한 결과, ACEPDG분획물은 glucose, inositol이 검출되었으며 ACIPDG, ACEPAG, ACIPAG 분획물은 glucose, fructose, inositol이 검출되었다.

• 생약학회지
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• 제30권4호
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• pp.355-362
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• 1999

New lectins have been isolated and purified from mung bean (Phaseolus radiatus) through physiological saline extraction, ammonium sulfate salt fractionation and column chromatographies. Ion exchanger were eluted by linear salt gradient and then further purified through gel filtration. Thus obtained lectin named as MBL. The gene expressions of 5 cytokines (IL-1, IL-2, IL-6, $TNF-{\aphpa}$ and $IFN-{\gamma}$) from human peripheral blood mononuclear cells (PBMC) stimulated with MBL were investigated by using reverse transcription polymerase chain reaction (RT-PCR). PBMC ($1{\times}106$ cells/ml) isolated from healthy volunteers were stimulated with lectins (4 mg/ml) for various time intervals (1 to 96 hrs). After each of the various stimulated times, total RNA was isolated and assessed for different cytokines mRNA by RT-PCR. The mRNA encoding IL-1, IL-2 were detected continuously from 1 to 20 hrs, and IL-6 was detected up to 24 hrs. But the mRNA encoding $IFN-{\gamma}$ and $TNF-{\alpha}$ were detected to 8 hours only and showed short time response compared with other cytokines. The significant expression of all cytokines mRNA were observed at 4 hrs. These results suggested that MBL, as inducer of cytokines could elicit detectable cytokine mRNA from PBMC.

• The Korean Journal of Ceramics
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• 제7권1호
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• pp.36-40
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• 2001

In order to fabricate uncooled IR sensors for pyroelectric applications, multilayered thin films of Pt/PbTiO$_3$/Pt/Ti/Si$_3$N$_4$/SiO$_2$/Si and thermally isolating membrane structures of square-shaped/cantilevers-shaped microstructures were prepared. Cavity was also fabricated via direct silicon wafer bonding and etching technique. Metallic Pt layer was deposited by ion beam sputtering while PbTiO$_3$ thin films were prepared by sol-gel technique. Micromachining technology was used to fabricate microstructured-membrane detectors. In order to avoid a difficulty of etching active layers, silicon-nitride membrane structure was fabricated through the direct bonding and etching of the silicon wafer. Although multilayered thin film deposition and device fabrications were processed independently, these could b integrated to make IR micro-sensor devices.

• BMB Reports
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• 제34권3호
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• pp.219-224
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• 2001

To identify the antioxidative peptides in the gelatin hydrolysate of bovine skin, the gelatin was hydrolyzed with serial digestions in the order of Alcalase, pronase E, and collagenase using a three-step recycling membrane reactor. The second enzymatic hydrolysate (hydrolyzed with pronase E) was composed of peptides ranging from 1.5 to 4.5 kDa, and showed the highest antioxidative activity, as determined by the thiobarbituric acid method. Three different peptides were purified from the second hydrolysate using consecutive chromatographic methods. This included gel filtration on a Sephadex G-25 column, ion-exchange chromatography on a SP-Sephadex C-25 column, and high-performance liquid chromatography on an octadecylsilane chloride column. The isolated peptides were composed of 9 or 10 amino acid residues. They are: Gly-Glu-Hyp-Gly-Pro-Hyp-Gly-Ala-Hyp (PI), Gly-ProHyp-Gly-Pro-Hyp-Gly-Pro-Hyp-Gly (PII), and Gly-ProHyp-Gly-Pro-Hyp-Gly-Pro-Hyp (PIII), as characterized by Edman degradation and fast-atom bombardment mass spectrometry. The antioxidative activities of the purified peptides were measured using the thiobarbituric acid method, and the cell viability with a methylthiazol tetrazolium assay The results showed that PII had potent antioxidative activity on peroxidation of linoleic acid. Moreover, the cell viability of cultured liver cells was significantly enhanced by the addition of the peptide. These results suggest that the purified peptide, PII, from the gelatin hydrolysate of bovine skin is a natural antioxidant, which has potent antioxidative activity.

• Journal of Microbiology and Biotechnology
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• 제17권1호
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• pp.21-28
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• 2007

The crude biopolymer (AS-S1) and endobiopolymer (AS-S2) were isolated from the dry stem bark of Acanthopanax sessiliflorus and tested for anti complement activity. The two potent anticomplement biopolymers, AS-1 and AS-2-Fr.I, were isolated by the combination of ion-exchange chromatography and gel filtration methods from the endo-biopolymers (AS-S2). The anticomplement activity of AS-1 (MW 12 kDa) and AS-2-Fr.I (MW 180 kDa) were found to be 84.4% and 100.0%, respectively, at the concentration of $25{\mu}g/ml$. Activated pathway of the complement system occurred in both classical and alternative pathways, as evidenced by crossed immunoelectrophoresis(CIEP), where a major pathway was detected to be the classical one. It was found that the anticomplement activities of the periodate oxidized were decreased significantly, but those of pronase digested biopolymers of AS-1 and AS-2-Fr.I were decreased very little. The AS-1 contained 2,4,6-tri-O-methyl-D-glucitol, 2,3,6-tri-O-methyl-D-galacitol, and 2,3,6-tri-O-methyl-D-galacitol, which indicated that AS-1 contained a $(1{\rightarrow}3),\;(1{\rightarrow}4)-linked$ glucopyranosyl residue and a $(1{\rightarrow}4)-linked$ galactosyl residue. AS-2-Fr.I contained mainly 2,4-di-O-methyl-D-mannitol and 2,3,4-tri-O-methyl-D-galacitol, which contained $(1{\rightarrow}3),\;(1{\rightarrow}6)$ linked mannosyl and $(1{\rightarrow}6)$ linked galactosyl residues.