• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.116-116
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• 2011

바이오 가스 플랜트의 혐기소화 공정에서 발생하는 바이오 가스는 중 유해가스인 황하수소($H_2S$)는 부식성 가스로 수천 PPM농도를 함유하여, 발전기나 가스보일러로 이용하는 경우에는 $H_2S$를 제거하는 탈황공정이 반드시 필요하다. 탈황방식에는 산화철 탈황(건식 탈황)과 생물 탈황이 현재 많이 사용되고 있어나 산화철 탈황은 산화철 pellet이 유화철에 변화하면 탈황능력이 저하되어 pellet을 교환해야 하며 많은 비용이 발생한다. 생물 탈황 방식은 유황산화세균의 서식활동조건(온도, 반응시간, 산소량)확보가 반드시 필요하여 높은 운전기술을 필요로 한다. 본 연구에서는 바이오가스 전처리 기술 중 활성탄 또는 약액을 이용한 기존의 탈황정제방식보다 흡착성능이 뛰어난 이온교환섬유를 이용하여, 황화수소($H_2S$)를 95% 이상 제거할 수 있는 고효율 섬유상 이온촉매 악취제거 시스템 개발을 수행하였다. 이온교환섬유는 방사선 조사를 이용하여 부직포에 라디칼을 인위적으로 형성시켜(그라프트 중합) 양이온 또는 양이온을 교환할 수 있도록 제조된 섬유상의 흡착제로, 이온교환 섬유의 화학적 이온교환과 물리적 흡착 및 탈착반응이 동시에 발생되고, 활성탄/실리카켈 보다 흡착능력이 2~4배 높다. 또한 이온섬유의 재생기능을 이용하여 장기적 다양한 악취($H_2S$, $NH_3$, 아민계, 메르갑탄류, 알데히드 등) 및 유해가스(VOCs, NOx, SOx) 등을 95% 이상 제거할 수 있다.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.210-215
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• 2014

Pseudomonas nitroreducens TX1 was isolated from a rice field drainage in Taiwan. The bacterium is of special interest because of its capability to use a group of nonionic surfactants such as alkylphenol polyethoxylates even at high concentrations as a sole carbon source. In this study, a small cryptic circular plasmid, pTX1, was characterized from P. nitroreducens TX1. It is 2,286 bp in length with a GC content of 63.3% and harbors three open reading frames, $Rep_{pTX1}$ and functionally unidentified ORF1 and ORF2. The predicted $rep_{pTX1}$ gene product is homologous to Rep proteins of plasmids belonging to the pC194/pUB110 family, which is predominantly found in Gram-positive bacteria and is known to replicate by the rolling-circle mechanism. The copy number of pTX1 was estimated to be about 150 in each cell. Based on the genetic fingerprints and comparison with other plasmids, it is concluded that pTX1 replicates by a rolling circle mechanism which is rarely found for Pseudomonas plasmids.

• Applied Chemistry for Engineering
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• v.27 no.5
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• pp.502-507
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• 2016

This study was conducted to develop novel antimicrobial nano-composites, with the aim of fully utilizing antimicrobial properties of multi-walled carbon nanotubes (MWCNTs), nickel (Ni) and zinc oxide (ZnO). Ni coated-MWCNTs (Ni-CNT) were prepared and evaluated for their potential application as an antimicrobial material for inactivating bacteria. Field emission scanning electron microscopy (FE-SEM), and X-ray energy dispersive spectroscopy (EDS) were used to characterize the Ni coating and morphology of Ni-CNT. Staphylococcus aureus (S. aureus) and Escherichia coil (E. coil) were employed as the target bacterium on antimicrobial activities. Comparing with the nitric acid treated MWCNTs and Ni-CNT which have been previously reported to possess antimicrobial activity towards S. aureus and E. coil, Ni-CNT/ZnO exhibited a stronger antimicrobial ability. The nickel coating was confirmed to play an important role in the bactericidal action of Ni-CNTs/ZnO composites. Also, the addition of ZnO to the developed nanocomposite is suggested to improve the antimicrobial property.

• Microbiology and Biotechnology Letters
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• v.14 no.3
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• pp.239-244
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• 1986

To develop the potential use as new host strain for gene cloning, alkaline-tolerant isolates from soil were examined for amylase activity, protease activity, antimicrobial activity and transformability by using plasmid pUB 110. Of these strains, one was selected and identified as Bacillus sp. YA-14. in the enzymatic properties of Bacillus sp. YA-14 the optimal conditions for the reaction of amylase and protease were at pH 0.8 and pH 7.5 respectively. The antimicrobial activity of Bacillus sp. YA-14 was also found. For the transformation, Bacillus sp. YA-14 was cultured to late logarithmic growth phase ai 37$^{\circ}C$ in modified SPI medium (pH 8.0) containing 0.4% MgSO$_4$. The presence of pUB 110 plasmid DNA in transformants was confirmed by electrophoresis and stably maintained in the new host.

• Journal of the Korean Chemical Society
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• v.55 no.1
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• pp.19-27
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• 2011

New series of Mn(II), Ni(II), Co(II), Cu(II) and Zn(II) of the 2-(benzothiazol-2-yl)-N'-(2,5-dihydroxybenzylidene) acetohydrazide have been synthesized and characterized by elemental analysis, IR, UV-vis, $^1H$-NMR, mass and ESR spectra, magnetic susceptibility and molar conductivity measurements. The spectral data and magnetic measurements of the complexes indicate that, the geometries are either square planar or octahedral. The biological activity of the ligand and its complexes against fungi (Aspergillus nigar and Fusarium oxysporium) were investigated. The metal complexes exhibited higher activity than both the parent ligand and the corresponding metal ion.

• The Korean Journal of Mycology
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• v.42 no.4
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• pp.333-340
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• 2014

The aim of this study was to isolate a potential multifunctional biocontrol agent from bacteria for control of multiple plant diseases as an alternative to fungicides. A total of 201 strains were isolated from soil undamaged by repeated cultivation in Sunchang and their ability to produce antibiotics, siderophores and extracellular enzymes such as protease, cellulase and amylase was investigated. Selected strain SCS3 produced cellulose, protease and amylase. This strain also produced siderophores and showed excellent antifungal activity against various phytopathogens. SCS3 was identified as Bacillus subtilis using 16S rRNA sequencing, and named Bacillus subtilis SCS3. Finally, physiological and biochemical characteristics of B. subtilis SCS3 were examined. From the results, B. subtilis SCS3 was found to be a useful multifunctional biocontrol agent against various phytopathogens.

• Food Science and Preservation
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• v.17 no.5
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• pp.608-615
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• 2010

We investigated the effect of grape-must temperature ($50^{\circ}C$, $60^{\circ}C$, and $70^{\circ}C$) on wine quality. We used Muscat Bailey A (MBA) grapes; these are often used in wine making in Korea. The numbers of viable bacteria, yeasts and molds in grape-must decreased with an increase in temperature. Polyphenol oxidase activities in grape-must were reduced at high temperatures. Redness; and, total anthocyanin, polyphenol, and tannin contents of MBA grape wine were higher after heating at $70^{\circ}C$ than after use of lower temperatures. Antioxidant activity was also enhanced after exposure to high temperatures, which may be attributable to the presence of increased levels of polyphenolic compounds in the grape-must. Thus, the heat treatment to prepare grape-must before wine fermentation greatly affects wine quality.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.730-739
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• 2015

108 microorganism types (79 types of fungi and 29 types of bacteria) were isolated from 25 automobiles generating bad odor when the air conditioner was turned on, and 43 types of fungi and 23 types of bacteria were identified. The analysis of condensate generated by the air conditioners in the automobiles indicated pH 6.4~7.1, 12.5~34.2 mg/L carbon source, 0.9~18.6 mg/L nitrogen source, 0.5~27.8 mg/L ion contents, and 0.1~7.7 mg/L mineral contents. The biofilms were formed by the mesophiles under the summer temperature/humidity condition ($26^{\circ}C$, 70% R.H.), and they were regenerated when the environmental factors (nutritional contents and temperature/humidity) were appropriate even after they were artificially removed. Although the antimicrobials removed 99.9% of planktonic cells within 15 minutes, they were not effective in removing biofilm. Up to 1,950 ppmv of ethanol was observed in the automobile treated with the antimicrobials. Although the figure is lower than the acute toxicity level when inhaled by humans, the health safety of the chemical substances used in the antimicrobials needs to be reviewed.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.4
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• pp.366-372
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• 2012

The aim of this study was to compare two commercial root canal medicaments, ProRoot MTA (Dentsply Tulsa, USA) and OrthoMTA (Bio MTA, Korea), by assessing the antimicrobial effects on three selected species commonly found in root canals of infected teeth, namely Enterococcus faecalis, Fusobacterium nucleatum and Staphylococcus epidermidis. Colonies of these bacteria were treated with varied concentrations of ProRoot MTA or OrthoMTA over different lengths of time. The results are as follows : 50, 25 and 12.5 mg/mL of ProRoot MTA or OrthoMTA did not completely inhibit the growth of E. faecalis, but a decreased growth rate was evident in comparison to the control (p < 0.05). 50 mg/mL of both materials successfully eliminated F. nucleatum during the first 24 hours. Regrowth of microbes after 24 hours, however, indicated a diminished effect of ProRoot MTA whereas OrthoMTA showed its continuously sustained antimicrobial actions (p < 0.05). 50 mg/mL of ProRoot MTA and 50, 25 mg/mL of OrthoMTA exerted their full antibacterial actions against S. epidermidis during the first 24 hours. Although the regrowth of colony was observed after 24 hours, the rate of growth was significantly decreased, approximating a complete inhibition (p < 0.05). The present study revealed that OrthoMTA, recently developed in Korea, had antimicrobial activity higher than ProRoot MTA.

• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.244-250
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• 1990

A bacterium capable of hydrotyzing raw starch was isolated from soil, which was identified as a strain of Bacillue. The effects of culture conditions and medium compositions on the enzyme production were investigated. Among tested carbon sources, soluble starch and wheat starch were most effective for the production of the enzyme, and the level of concentration for the optimal enzyme production was 0.5%. For nitrogen sources, polypeptone was best for the enzyme production, with the level of 0.5%. The enzyme was maximally produced by cultivating the organism at medium of initial pH 6.5, and temperature of $35^{\circ}C$. The enzyme was partially purified by Sepharose CL-6B gel filtration and DEAESephacel ion-exchange chromatography. The optimal pH and temperature for the enzyme reaction were 6.5 and $70^{\circ}C$, respectively. The enzyme most stable at pH 8.0, and temperature up to $60^{\circ}C$. In kinetic studies, the k, values for corn, wheat, rice and potato starch were 1.7, 1.4,2.5 and 1.090, respectively.