Alkaline protease 를 생산하는 미생물의 분리 , 동정 및 효소성질

강상모,신공식,고정연 한국농화학회 2000 Applied Biological Chemistry (Appl Biol Chem) Vol.43 No.3

For the development of enzyme detergent capable of effectively washing at low temperature, a bacterium producing alkaline protease was isolated from soil samples, and properties of the enzyme were investigated. The selected strain was Gram negative, rod shape(0.6∼0.7×1.3∼2.6 ㎛ in size) and motile. It had the degradation activity of aesculin, gelatin and casein, and was catalase-positive. The cell wall components was meso-DAP, and G+C mole contents was 43.3%. From these results, the strain was identified as Acinetobacter sp. KN-27. The activity of alkaline protease by this strain peaked with 3,300 D.U/mL after 36 hours in the liquid culture at 40℃. The optimal pH and temperature of the enzyme were pH 9 and 60℃, respectively. Alkaline protease produced by Acinetobacter sp. KN-27 has shown two active bands on the electrophoresis of native gel.

스펙트럴 영역분할 격자 삽입법을 이용한 채널유동의 큰 에디 모사

강상모,변도영,백승욱,Gang, Sang-Mo,Byeon, Do-Yeong,Baek, Seung-Uk 대한기계학회 1998 大韓機械學會論文集B Vol.22 No.7

One of the main unresolved issues in large-eddy simulation(LES) of wall-bounded turbulent flows is the requirement of high spatial resolution in the near-wall region, especially in the spanwise direction. Such high resolution required in the near-wall region is generally used throughout the computational domain, making simulations of high Reynolds number, complex-geometry flows prohibitive. A grid-embedding strategy using a nonconforming spectral domain-decomposition method is proposed to address this limitation. This method provides an efficient way of clustering grid points in the near-wall region with spectral accuracy. LES of transitional and turbulent channel flow has been performed to evaluate the proposed grid-embedding technique. The computational domain is divided into three subdomains to resolve the near-wall regions in the spanwise direction. Spectral patching collocation methods are used for the grid-embedding and appropriate conditions are suggested for the interface matching. Results of LES using the grid-embedding strategy are promising compared to LES of global spectral method and direct numerical simulation. Overall, the results show that the spectral domain-decomposition grid-embedding technique provides an efficient method for resolving the near-wall region in LES of complex flows of engineering interest, allowing significant savings in the computational CPU and memory.

휘발성 유기 화합물, 공기 중 박테리아, 바이러스 저감을 위한 산화아연/탄소 섬유 복합체 개발

강상모,박대훈,황정호 한국대기환경학회 2021 한국대기환경학회 학술대회논문집 Vol.2021 No.10

섬유 기반 필터를 통한 공기 정화는 실내 대기 오염제어의 기본적이며 기초적인 요구 사항이 되었다. 그러나 기존 필터는 입자상 물질 제거 능력은 뛰어나지만 가스 저감 및 미생물 살균 효과가 적은 고분자 섬유 필터에 의존하고 있다. 이 연구는 산화아연(ZnO)-나노가시가 표면에 자라난 활성탄소 나노섬유(I@ZnO/ACNFs)의 광촉매적 휘발성 유기 화합물(VOC) 산화 및 항균, 항바이러스 특성과 대기 오염제어 및 감염 예방 가능성에 대해 다룬다. 전기방사중에 무기염의 이온 분리를 유도할 수 있는 새로운 기술을 개발함으로써 표면에 아연(Zn) 성분이 집중된 나노섬유를 합성하였다. I@ZnO/ACNFs는 높은 종횡비의 ZnO 나노 가시로 조밀하게 덮인 표면을 지니며, 공기 중 병원체에 대한 상당한 치사율과 VOC에 대한 향상된 광촉매 활성을 나타냈다. 더욱이, 빠른 기류하에서 ACNF에 대한 ZnO의 우수한 접착 안정성이 관찰되었다. 독특한 형태에서 파생된 흥미로운 항균, 항바이러스 성능 및 강력한 VOC 제거 기능과 함께 새로 개발된 I@ZnO/ACNFs는 공기 중 미생물 비활성화, 효과적이고 지속 가능한 VOC 정화, 광살균 및 광촉매 재료 설계에 대한 잠재력을 제시한다.

나란히 배열된 한 쌍의 원형실린더를 지나는 유동 특성

강상모,Kang, Sang-Mo 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.7

Two-dimensional flow over a pair of circular cylinders in a side-by-side arrangement at low Reynolds numbers has been numerically investigated in this study Numerical simulations are performed, using the immersed boundary method, for the ranges of 40$\leq$Re$\leq$160 and $g^{*}$<5, where Re and $g^{*}$ are, respectively, the Reynolds number and the spacing between the two cylinder surfaces divided by the cylinder diameter. Results show that a total of six kinds of wake patterns are observed over the ranges: antiphase-synchronized, inphase-synchronized, flip-flopping, single bluff-body, deflected, and steady wake patterns. It is found that the characteristics of the flow significantly depends both on the Reynolds number and gap spacing, with the latter much stronger than the former. Instantaneous flow fields, time traces, flow statistics and so on are presented to identify the wake patterns and then to understand the underlying mechanism. Moreover, the bifurcation phenomenon where either of two wake patterns can occur is found at certain flow conditions.ons.

능동적 벽 운동을 수반하는 난류운동의 해석을 위한 근사 좌표변환

강상모 대한기계학회 2001 大韓機械學會論文集B Vol.25 No.11

Numerical Study on Laminar Flow over Three Side-by-Side Cylinders

강상모 대한기계학회 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.10

The present study has numerically investigated two-dimensional flow over three circular cylinders in an equidistant side-by-side arrangement at a low Reynolds number. For the study, numerical simulations are performed, using the immersed boundary method, in the range of g? < 5at Re = 100, where g? is the spacing between two adjacent cylinder surfaces divided by the cylinder diameter. Results show that the flow characteristics significantly depend on the gap spacing and a total of five kinds of wake patterns are observed over the range: modulation-synchronized (g? >∼ 2), inphase-synchronized (g? ? 1.5), flip-flopping (0.3 < g? <∼ 1.2), deflected (g? ? 0.3), and single bluff-body patterns (g? < 0.3). Moreover, the parallel and symmetric modes are also observed depending on g? in the regime of the flip-flopping pattern. The corresponding flow fields and statistics are presented to verify the observations.

원형실린더를 지나는 균일전단 유동에 관한 수치연구

강상모,최원호 대한기계학회 2005 大韓機械學會論文集B Vol.29 No.1

회전하는 원형실린더를 지나는 균일전단 유동에 관한 수치연구

강상모 대한기계학회 2005 大韓機械學會論文集B Vol.29 No.5

Bacillus stearothermophilus KY-126가 생산하는 Cyclodextrin glycosyltransferase의 정제 및 특성

강상모,유시형,Kang, Sang-Mo,Yoo, Si-Hyung 한국식품과학회 1994 한국식품과학회지 Vol.26 No.4

토양을 대상으로 하여 CGTase를 생산하는 균주를 분리, 선별하여 Bacillus stearothermophilus KY-126을 얻었다. CGTase의 정제는 ammonium sulfate precipitation, ion exchange chromatography, gel filtration의 과정을 통해 분리 정제하여 단일 효소를 얻었으며, 분자량은 약 67,000이었다. 효소 반응의 최적 온도는 $65^{\circ}C$였으며, $55^{\circ}C$에서 30분간 열처리에도 비교적 열에 안정하였다. 최저 활성 pH는 5.5였고 pH5.5에서 10.5까지 비교적 안정하였다. $HgCl_{2}$에 의해 저해를 받았으며, 그 외의 금속 이온에는 저해를 받지 않았다. Soluble starch로부터 CD의 전환율은 43%이었으며, ${\alpha}-:,\;{\beta}-:,\;{\gamma}-$, CD의 생성 비율은 2.9 : 2.1 : 1이었다. A bacterial strain No. KY-126, which produced extracellular cyclodextrin glycosyltransferase(CGTase), was isolated from soil and identified as Bacillus stearothermophilus KY-126. The enzyme was purified by the treatments of ammonium sulfate precipitation, DEAF-Sephadex, Sephadex G-100 column chromatography. The optimal pH and temperature for the enzyme activity were pH 5.5 and $65^{\circ}C$, respectively. And the enzyme was stable at pH values from 6.0 to 11.0 at $55^{\circ}C$ for 30 min and stable up to $60^{\circ}C$ for 30 min.. The enzyme was inhibited by $HgCl_{2}$. The molecular weight of the enzyme was estimated to be 67,000 by using SDS-PAGE. The maximum conversion from starch to cyclodextrin (CD) by CGTase was 43% and obtained at 6 hr reaction and the ratio of ${\alpha}-,\;{\beta}-,\;{\gamma}-$, CD production at this time was 2.9 : 2.1 : 1.0.

Biosurfactant를 생산하는 P. aeruginosa. KK-7의 분리 및 Biosurfactant의 생산

강상모,김대원,김혜자 한국산업미생물학회 1994 한국미생물·생명공학회지 Vol.22 No.1

토양 및 균원시료에서 물의 표면장력을 저하시키는 biosurfactant 생산균주 KK-7을 분리하여 동정한 결과 Pseudomonas aeruginosa로 판명되었다. 배지 영양인자의 검토 결과, 일반적으로 소수성 탄소원을 이용하는 biosurfactant 생산균주들의 성질과는 달리 탄소원으로 glucose 1%을 이용한 biosurfactant를 생산 능력이 우수하였다. 질소원은 tryptone 0.5%, yeast extract 0.2%의 복합질소원을 이용시에 높은 활성을 나타내었다. 또한 배지의 알칼리성 조건이 생산에 유리하였다. 50시간의 배양시간에서 최대 생산량을 나타내었으며 각기 다른 유화능력과 표면활성을 가지는 biosurfactant를 생산한다고 보인다. Biosurfactant 최대생산량은 CMC 5로 약 5 g/L였다. The bacteria which secrete surface-active agent and decrease the surface tension of culture broth were isolated from soil samples. Among them, biosurfactant producing strain KK-7 was selected and emulsification was also detected. The KK-7 produced biosurfactant not only lipid but also glucose by using carbon source. Taxonomical characterization tests have demonstrated the strain KK-7 to be Pseudomonas aeruginosa. The media composition of the P. aeruginosa KK-7 for the biosurfactant production was 1% glucose, 0.5% tryptone, 0.2% yeast extract, 0.15% potassium phosphate mono-dibasic, 0.05% MgSO_4, initial pH 8.5, at 30℃ for 2 days. In this condition, the concentration of biosurfactant was reached CMC 5 in the culture broth. Surface active material was produced maximum at stationary phase, but emulsification power was higher at log phase than stationary phase. It was considered that P. aeruginosa KK-7 produced biosurfactant more than one type having different properties and each maximum production time was different. The minimun surface tension of biosurfactant in 50mM Tris buffer (pH 8.0) was 28 dyn/㎝, and CMC was 1 g/L.