• Asian-Australasian Journal of Animal Sciences
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• 제11권6호
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• pp.661-672
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• 1998

Two experiments were conducted to examine the effects of a range of concentrations of ruminal fluid ammonia ($NH_3$-N) on forage digestibility, microbial growth efficiency and the mix of microbial species. Urea was either continuously infused directly into the rumen of sheep fed 33.3 glh of oaten chaff (Exp. I) or sprayed onto the oaten chaff (750 g/d) given once daily (Exp. 2). Concentrations of $NH_3$-N increased with incremental addition of urea (p < 0.01). Volatile fatty acids (VFA) concentrations and 24 h in sacco organic matter digestibility in the rumen were higher when supplemental urea was given (p < 0.01). The (C2 + C4) : C3 VFA ratio was lower (p < 0.05) when $NH_3$-N was above 200 mgN/I. The fungal sporangia appearing on oat leaf blades were significantly higher when urea was supplemented, indicating that $NH_3$-N was a growthlimiting nutrient for fungi at levels of $NH_3$-N below 30 mgN/l. The density of protozoa was highest when $NH_3$-N concentrations were adjusted to 30 mgN/I for continuously fed ($4.4{\times}10^5/ml$) and to 168 mgN/1 for once daily feeding ($2.9{\times}10^5/ml$). Thereafter increasing concentrations of $NH_3$-N, were associated with a concomitant decline in protozoal densities. At the concentration of $NH_3$-N above 200 mgN/l, the density of protozoa was similar to the density of protozoa in ruminal fluid of the control sheep ($1.8{\times}10^5/ml$). The efficiency of net microbial protein synthesis in the rumen calculated from purine excretion was 17-47% higher when the level of $NH_3$-N was above 200 mgN/1. The possibilities are that 1) there is less bacterial cell lysis in the rumen because of the concomitant decrease in the protozoal pool and/or 2) microbial growth per se in the rumen is more efficient with increasing $NH_3$-N concentrations.

• 한국농공학회논문집
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• 제56권6호
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• pp.169-176
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• 2014

To evaluate bio-cementation of microbial on sands, laboratory test was conducted using acrylic cubic molding boxes ($5cm{\times}5cm{\times}5cm$). It was incubated the microbial, called Bacillus Pasteurii, according to Park et al (2011, 2012). and applied 50ml each specimen. Two type of sand samples used were Jumoonjin sand and common sand (well graded). These sands were molded in acrylic boxes with the relative density of 30 % and 60 % respectively. Microbial were poured onto the samples molded in acrylic boxes and cured at the room temperature and humidity. After 7, 14 and 21days, it was measured the compressive strength, pH, EC, and density and it were observed SEM and XRD to verify the effect of bio-cementation. It was found that bio-cementation was increased a strength of sands and it was appeared that strengths were related to the type of sand and relative density. Therefore it was confirmed the solidification of sands using the bio-cementation by microbial activation and the usefullness of acrylic molding boxes when tests were conducted on the soil of sands.

• 상하수도학회지
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• 제26권3호
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• pp.355-360
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• 2012

The characteristics of power generation were investigated by changing the electrical conductivity from 10 to 40mS/cm using air-cathode microbial fuel cell, which had graphite fiber fabric(GFF) anode. There were three kinds of cathode used: one was carbon cloth cathode coated with Pt, another was carbon nanotube(CNT) cathode with non-precious catalyst of Fe-Cu-Mn, and the other was carbon nanotube(CNT) cathode without any catalyst. When it was operated in batch mode, power density of 1369.5mW/$m^2$ was achieved at conductivity of 20mS/cm. Power density from MFC with CNT cathode coated with multi-catalyst of Fe-Cu-Mn was shown about 985.55mW/$m^2$, which was 75.1% compared the power density of carbon cloth coated with Pt. This meant that CNT cathode coated with multi-catalyst of Fe-Cu-Mn could be an alternative of carbon cloth cathode.

• 한국토양비료학회지
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• 제31권2호
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• pp.204-210
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• 1998

본 시험은 재배이역(栽培履歷)이 서로 상이한 시설재배지에서의 염류집원적지(鹽類集源積地)와 건전지(健全地)의 미생물상(微生物相)의 생태(生態)를 비교해석(比較解析)하고, 미생물(微生物)적 진단(診斷)에 의한 근권환경(根圈環境)의 동태(動態)와 개량기술(改良技術)을 위한 기초자료를 얻고자 수행하였다. 주요 미생물(微生物)의 분포(分布)는 건전지(健全地)에서 형광성(螢光性) Pseudomonas 속 세균(細菌)의 밀도가 높은반면 염류장해지(鹽類障害地)에서는 병원성(病原性) Fuasarium 속의 밀도가 높고 형광성(螢光性) Pseudomonas 속 세균(細菌)이 낮은 분포밀도(分布密度)를 보였다. 토양중 유기물 함량이 증가할수록 Bacillus 속(屬), 형광성(螢光性) Pseudomonas 속(屬), Enterobacteriaceae 등 세균류(細菌類)의 밀도와 Microbial biomass C함량이 크게 증가하였으며, 토양의 전기전도도(電氣傳導度)(EC)가 $5.1dS\;m^{-1}$ 이상으로 높아지면 미생물(微生物)간의 비율중 세균(細菌)/사상균(絲狀菌)(B/F), 방선균(放線菌)/사상균(絲狀菌)(A/F)의 비율이 현저히 낮아지고 형광성(螢光性) Pseudomonas 속(屬) 세균(細菌)이 급격히 감소하였다. 토양 pH와 세균(細菌)과의 관계는 고도의 정(正)의 상관관계(相關關係)를, 사상균(絲狀菌)과는 부(負)의 상관관계(相關關係)를 보였으며, 토양유기물과 방선균(放線菌), Bacillus 속(屬), Enterobacteriaceae와는 각각 $r=0.226^*$, $r=0.334^{**}$, $r=0.276^{**}$, 치환성 Ca및 치환성 Mg함량과 방선균수(放線菌數)와는 각각 $r=0.334^{**}$, $r=0.352^{**}$, 유기물함량과 Microbial biomass C 함량과는 $R=0.439^{**}$의 유의성(有意性) 있는 상관을 보였다.

• Journal of Microbiology and Biotechnology
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• 제26권11호
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• pp.1871-1880
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• 2016

Bio-oxidation is an effective technology for treatment of refractory gold concentrates. However, the unsatisfactory oxidation rate and long residence time, which cause a lower cyanide leaching rate and gold recovery, are key factors that restrict the application of traditional bio-oxidation technology. In this study, the oxidation rate of refractory gold concentrates and the adaption of microorganisms were analyzed to evaluate a newly developed two-step pretreatment process, which includes a high temperature chemical oxidation step and a subsequent bio-oxidation step. The oxidation rate and recovery rate of gold were improved significantly after the two-step process. The results showed that the highest oxidation rate of sulfide sulfur could reach to 99.01 % with an extreme thermophile microbial community when the pulp density was 5%. Accordingly, the recovery rate of gold was elevated to 92.51%. Meanwhile, the results revealed that moderate thermophiles performed better than acidophilic mesophiles and extreme thermophiles, whose oxidation rates declined drastically when the pulp density was increased to 10% and 15%. The oxidation rates of sulfide sulfur with moderate thermophiles were 93.94% and 65.73% when the pulp density was increased to 10% and 15%, respectively. All these results indicated that the two-step pretreatment increased the oxidation rate of refractory gold concentrates and is a potential technology to pretreat the refractory sample. Meanwhile, owing to the sensitivity of the microbial community under different pulp density levels, the optimization of microbial community in bio-oxidation is necessary in industry.

• Bulletin of the Korean Chemical Society
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• 제29권1호
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• pp.168-172
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• 2008

A microbial fuel cell is a noble green technology generating electricity from biomass and is expected to find applications in a real world. One of main hurdles to this purpose is the low power density. In this study, we constructed a prototype microbial fuel cell using Proteus vulgaris to study the effect of various reaction conditions on the performance. Main focus has been made on the modification of the anode with electropolymerized polypyrrole (Ppy). A dramatic power enhancement was resulted from the Ppy deposition onto the reticulated vitreous carbon (RVC) electrode. Our obtained maximum power density of 1.2 mW cm-3 is the highest value among the reported ones for the similar system. Further power enhancement was possible by increasing the ionic strength of the solution to decrease internal resistance of the cell. Other variables such as the deposition time, kinds of mediators, and amount of bacteria have also been examined.

• Environmental Engineering Research
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• 제24권3호
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• pp.443-448
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• 2019

The present study was conducted to compare the voltage generation in two-chamber microbial fuel cells (MFCs) with a biocathode where nitrate and oxygen are used as a terminal electron acceptors (TEA) and to investigate the nitrogen removal and the electrochemical characteristics depending on the separators of the MFCs for denitrification. The maximum power density in a biocathode MFC using an anion exchange membrane (AEM) was approximately 40% lower with the use of nitrate as a TEA than when using oxygen. The MFC for denitrification using an AEM allows acetate ($CH_3COO^-$) as a substrate and nitrate ($NO_3{^-}$) as a TEA to be transported to the opposite sides of the chamber through the AEM. Therefore, heterotrophic denitrification and electrochemical denitrification occurred simultaneously at the anode and the cathode, resulting in a higher COD and nitrate removal rate and a lower maximum power density. The MFC for the denitrification using a cation exchange membrane (CEM) does not allow the transport of acetate and nitrate. Therefore, as oxidation of organics and electrochemical denitrification occurred at the anode and at the cathode, respectively, the MFC using a CEM showed a higher coulomb efficiency, a lower COD and nitrate removal rate in comparison with the MFC using an AEM.

• Weed & Turfgrass Science
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• 제6권4호
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• pp.322-332
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• 2017

골프장 잔디 관리에서 미생물제제는 잔디의 생육 및 품질을 개선하고, 병을 예방하기 위해 사용되어왔다. 본 연구는 유산균(Lactobacillus fermentum)을 함유하는 미생물제제의 처리에 따른 크리핑 벤트그래스의 생육과 품질에 미치는 영향을 조사하였다. 처리구는 무처리구(NF), 대조구(CF), 미생물제제 처리구(MFcL: microbial fertilizer containing L. fermentum; MFL: CF+MFcL $1.0g\;m^{-2}$; 2MFL: CF+ MFcL $2.0g\;m^{-2}$) 및 미생물제제 단독 처리구(OMF; MFcL $1.0g\;m^2$)로 설정하였다. 시험 종료 후 토양 화학성은 처리구별 차이를 나타내지 않아 MFcL의 처리가 토양 이화학성에 미치는 영향은 미미하였다. MFcL 처리 시 잔디의 시각적 품질, 잔디 예지물, 잔디 중 무기 성분 함량 및 흡수량은 대조구와 비슷하였다. 잔디 밀도는 MFcL처리구에서 대조구에 비해 약 20% 정도 증가하였다. 이들 결과는 유산균을 함유하는 미생물제제의 처리는 크리핑 벤트그래스의 밀도를 향상에 기여하는 것을 확인하였다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제8권3호
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• pp.205-209
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• 2003

Solubilization of domestic household waste through Steam explosion with Subsequent ethanol production by the microbial saccharifitation and fermentation of the exploded product was studied. The effects of steam explosion on the changes of the density, viscosity, pH, and amounts of extractive components in artificial household waste were determined. The composition of artificial waste used was similar to leftover waste discharged from a typical home in Japan. Consecutive microbial saccharification and fermentation, and simultaneous microbial saccharification and fermentation of the Steam-exploded product were attempted using Aspergillus awamori, Trichoderma viride, and Saccharomyces cerevisiae; the ethanol yields of each process were compared. The highest ethanol yield was obtained with simultaneous microbial saccharification and fermentation of exploded product at a steam pressure of 2 MPa and a steaming time of 3 min.

• 공업화학
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• 제23권3호
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• pp.297-301
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• 2012

미생물연료전지는 미생물의 신진대사 활동을 통해 자발적으로 바이오매스를 전기로 전환시키는 바이오 전기화학 시스템이다. 본 연구에서는 미생물 접종원으로 활성슬러지를 사용하였으며, 미생물연료전지의 전기생산을 위한 기질로서 유가공 폐수의 적용 가능성을 검토하였다. 전력발생 장치로서 미생물연료전지의 성능을 파악하고자 전지전위, 전력밀도, 순환전압전류 분석 및 지속가능 전력생산에 관한 특성을 유가공 폐수를 적용하여 평가하였다. Chemical Oxygen Demand (COD) 2650 mg/L의 유가공 폐수를 이용한 미생물연료전지 시스템에서 COD가 88% 제거되었으며, 최대 전력밀도는 $40\;mW/m^2$에 도달하였다. 본 연구 결과로부터 유가공 폐수를 효과적으로 처리하는 동시에 전기를 생산하기 위한 미생물연료전지 기술의 적용 가능성을 확인하였다.