• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.380-387
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• 2002

To investigate the effects of xylooligosaccharides on the in vitro growth of intestinal bacteria, various species were cultivated individually on the m-PYF medium containing a carbon source (0.5% w/v) such as xylooligosaccharides, isomaltooligosaccharides, fructooligosaccharides and sucrose, respectively. The health-promoting microorganisms such as Bifidobacterium bifidum, Bifidobacterium infantis, Bifidobacterium longum, Lactobacillus casei and Lactobacillus acidophilus grew more effectively by xylooligosaccharides than by other carbon source, though xylooligosaccharides inhibited the growth of Clostridium perfringens, Bacteroides fragilis, Escherichia coli, Staphylococcus aureus and Salmonella typhumurium. At the mixed culture xylooligosaccharides exerted a preferential stimulatory effects on numbers of the health-promoting microorganisms, while xylooligosaccharides inhibited populations of potential pathogens at relatively low level. Xylooligosaccharides also maintained the acidity of culture with Streptococcus mutans, caries-inducing bacteria, over pH 5.0. These results suggest that xylooligosaccharides selectively promote the growth of the health-promoting microorganisms in human intestine and prevent caries by inhibiting acid production from Streptococcu mutans.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.4
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• pp.431-437
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• 2005

In this study, the profiles of the bacterial regrowth of indigenous bacteria in tap water and Pseudomonas fluorescence P17 were investigated for cases when carbon (glucose), and/or nitrogen ($NO_3^-$-N), and/or phosphorus ($PO_4^{3-}$-P) were added below sufficient nutrient concentration (SNC) and when carbon sources (glucose and acetate) and nitrogen sources ($NH_4^+$-N and $NO_3^-$-N) were added together. The bacterial regrowth was decreased with limitation of nutrients, and were lowered relatively in the sample, which plural nutrients were limited. In addition, phosphate might be the effective nutrient to control the bacterial regrowth in drinking water because the bacterial regrowth was significantly decreased by the limitation of phosphate. In contrast, the bacterial regrowth was retarded with increasing the concentration of $NO_3^-$-N. For simultaneously adding carbon(glucose or acetate) and nitrogen sources ($NH_4^+$-N and $NO_3^-$-N), the regrowth counts appeared highly in the condition, for both glucose and acetate. And, the regrowth was increased with increasing $NH_4^+$-N concentration as a nitrogen source.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.377-381
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• 2006

실험실 규모의 토양컬럼을 사용하여 도금폐수처리장의 유출수를 대상으로 처리한 결과 다음과 같은 결론을 얻었다. 1) 유입수 $NH_4-N$의 대부분은 질산화 토양컬럼에서 질산화 되었으며 HRT가 단축되면 제거율이 낮아졌다. 2) 질산화 토양컬럼에서 생성된 $NO_3-N$은 탈질 토양컬럼에서 탄소원이 없으면 탈질이 이루어지지 않지만 탄소원으로 메탄올을 주입하면 대부분의 $NO_3-N$는 탈질되었다. 3) 탈질 토양컬럼에서 HRT 72시간일때 T-N 제거율은 81.5%이었고 HRT 48시간일 때는 77.8%이었다. 4) 유입수 평균 T-P농도는 13.06 mg/L이고 탈질 토양컬럼에서의 유출수 평균 T-P는 0.83 mg/L로 제거율은 96.83% 이었다. 5) 실험기간 동안의 COD변화는 탄소원으로 메탄올 주입했 때와 HRT 변화시를 제외하고는 25 mg/L이하로 처리되었으며, 질산화 토양컬럼에는 폐굴껍질을 충진한 결과 $NO_3-N$의 생성에도 불구하고 pH 8.5정도를 유지할 수 있었다.

• Journal of the Korean Vacuum Society
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• v.17 no.6
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• pp.566-575
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• 2008

We investigated the field emission characteristics from the planar field emitters made of double-walled carbon nanotubes (DWCNTs) synthesized by a catalytic chemical vapor deposition (CCVD) method. Transmission electron microscopy, Thermogravimetric and Raman analysis showed that the carbon materials have a low defect level in their atomic carbon structure, pointing to the synthesis of high-purity DWCNTs. For field emission properties of DWCNTs, the turn-on field of DWCNTs was $1.9\;V/{\mu}m$ and the current density was about $74\;mA/cm^2$ at $8.1\;V/{\mu}m$, which is sufficient for the applications of field emission displays and vacuum microelectronic devices. The DWCNT field emitters also exhibited a uniform field emission pattern and good field emission stability in a diode configuration.

• Composites Research
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• v.19 no.1
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• pp.36-42
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• 2006

MWNT(multi-walled carbon nanotube)-filled plain-weave glass/epoxy composites were fabricated and electromagnetic characteristics of the composites were investigated. The observation of the microstructures of the composites revealed that MWNTs are mostly distributed in matrix rich region and the interface between glass fiber yarns in warp and fill direction. The permittivity of the composites, measured in X-band (8.2-12.4 GHz) frequency range, increased with weight fraction of MWNTs and remained almost constant with frequency. The measured permittivity was used to investigate the reflection loss of radar absorbing structures (RAS) composed of MWNT-filled composites according to thickness and a RAS were constructed with 10 dB absorbing bandwidth 4.2 GHz and 3.3 mm in thickness.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1975.12a
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• pp.180.2-180
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• 1975

Methanol을 유일한 탄소원으로 하여 생육할 수 있는 박테리아, Methanomonas sp.를 국내에서 토양으로부터 분리하였다. 이 군주를 이용하여 미생물 단백 생산을 위하여 연속 발효 방법을 연구 검토하였다. 연속 발효 조작을 이용하여 미생물 균체 생산율을 최대로 할 수 있는 긍정의 최적화가 연구되었다. 이에 필요한 이론과 실험방법 그리고 실험 결과가 검토될 것이다.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1243-1252
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• 2000

The differential enhanced degradation of cis- and trans-1,3-D was observed in the previous two studies performed by several researchers. This study was initiated to investigate the involvement of microorganisms in the differential enhanced degradation of the chemicals. As expected, microorganisms were responsible for the enhanced degradation. A mixed bacterial culture capable of degrading 1,3-D was isolated from an enhanced soil sample collected from a site treated with 1,3-D. Similar to the enhanced soil, the mixed culture degraded trans-1,3-D faster than cis-1,3-D. This mixed culture could not utilize cis- and trans-1,3-D as a sole source of carbon for growth. Rather, a variety of second substrates were evaluated to stimulate the differential enhanced degradation of the two isomers. As a result, the mixed culture degraded cis- and trans-1,3-D only in the presence of a suitable second substrate. Therefore, it appeared that the degradation of cis- and trans-1,3-D was a cometabolic process. Second substrates that had the capacity to stimulate the degradation included soil leachate, tryptone, tryptophan, and alanine. Other substrates tested. including soil extract. glucose, yeast extract and indole, failed to stimulate the degradation of the two isomers. The mixed culture was composed of four morphologically distinctive colonies on L-agar plates.

• Korean Journal of Medicinal Crop Science
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• v.8 no.1
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• pp.9-13
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• 2000

To determine the proper carbon and nitrogen sources and their proper levels for mass micro propagation of Scrophularia buergeriana Miquel, tonic and curing cough experiment were applied and a method for mass cultivation by using bioreactors (2.5 L) was expinined. Proper ratio of $NH_4NO_3\;:\;$KNO_3$ was 413 mg/L : 1900 mg/L for multiple shoot production. Sucrose was more effective than glucose or fractose as carbon source and 3% concentration was good for shoot formation. Total nitrogen was not detected after six weeks both in 500 ml flask and bioreactor culture. Sucrose was decreased sharply after two weeks and there was no sucrose left after three weeks both in 500 ml flask and bioreactor culture. The stirrer in bioreactor caused shear stress to shoots severely. The sphere type bioreactor was better than the cylinder type and removal of inner loop in sphere type was more effective to avoid shear stress.

• The Korean Journal of Mycology
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• v.41 no.1
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• pp.42-46
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• 2013

Burkholderia pyrrocinia CAB08106-4 was parceled out from the Chungnam Agricultural Research and Extension Center, Korea to evaluate the antagonistic activity against garlic white rot caused by Sclerotium cepivorum. The optimum cultural conditions including temperature, pH, enzyme activity, carbon and nitrogen sources were determined. The optimum culture conditions of B. pyrrocinia CAB08106-4 were $286^{\circ}C$, 150 rpm and pH 7. Chitinase only showed activity among several tested enzymes. The highest cell growth was obtained with 1% glucose and 0.1% $(NH_4)_2SO_4$, respectively.

• Applied Biological Chemistry
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• v.23 no.4
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• pp.211-217
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• 1980

Using Streptomyces chibaensis, which produces a strong inulin-hydrolyzing enzyme, the optimum cultural conditions and composition of the medium for the production of inulase were studied. 1. The highest enzyme activity was obtained at pH 7.5 after 84 hours culture at $30^{\circ}C$. 2. None of carbon source better than inulin was found. 3. $(NH_4)_2HPO_4$ and corn steep liquor were favourable inorganic and organic nitrogen sources for the production of inulase. 4. $KCl,\;MgSO_4\;and\;FeSO_4$ as the metallic salts were effective for the enzyme production at their concentrations of 0.01, 0.05 and 0.0001%, respectively. 5. The highest production of inulase was obtained from the medium of inulin 1.0% and corn steep liquor 2.0% concentrations, respectively.