• 한국물환경학회지
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• 제20권6호
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• pp.583-588
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• 2004

This research examined the treatment efficiency and methane production rate in treating slurry-type swine waste using UASB (upflow anaerobic sludge blanket) reactor. The UASB reactor was operated at an organics volumetric loading rate (VLR) of $2.6-15.7kgCOD/m^3/day$. A stepwise increase of the VLR resulted in a temporary deterioration in the COD removal rate in UASB reactor but recovered quickly. The COD removal rate were 65-70% for VLR up to $5 kgCOD/m^3/day$. When organics VLR was $10kgCOD/m^3/day$, the COD removal rate decreased sharply and there was loss of 17.537g of the seeding biomass due to sludge washout. This result indicated that the UASB system cannot be adapted to more than $10kgCOD/m^3/day$ of VLR. As the organic load increased from 2.6 to $15.7kgCOD/m^3/d$, the biogas production rate varied from 3.2 to 10.8 L/d and the methane conversion rate of the organic matter varied from 0.30 to $0.23m^3CH_4/kg\;COD_{removed}$. The methane content showed the range of 70.1-81.5% during the experimental period. The volatile solids (VS) removal efficiency was similar at the low VLR (< $5 kgCOD/m^3/day$), but it decreased sharply at the high VLR (> $5 kgCOD/m^3/day$). The VS reduction rate was, moreover, large those of COD. The result shows that hydraulic retention time above 2 days is essential in case of treating wastewater containing 1% of solids.

• 공업화학
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• 제20권2호
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• pp.213-217
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• 2009

폐수처리와 동시에 전기를 생산할 수 있는 새로운 대체 에너지 기술로 주목받고 있는 미생물 연료전지(microbial fuel cell, MFC)는 혐기성 조건의 산화전극(anode)에서 미생물에 의한 촉매작용을 통해 유기물질을 분해하면서 화학에너지를 전기에너지로 전환시키는 장치이다. 본 연구에서는 MFC의 성능을 파악하기 위하여 도시하수를 사용하여 폐수처리 효율과 전기생산 특성을 평가하였다. 도시하수에 탄소원으로서 acetate를 주입하였을 때 COD 제거율은 75.7%에서 88.2%로 증가하였으며 전압은 0.22 V에서 0.4 V까지 급격하게 상승하였다. 다양한 외부저항 하에서 전기생산에 미치는 산화전극과 환원전극(cathode) 사이의 전극 거리에 대한 영향 및 산화전극의 표면적에 대한 영향을 조사하였다. 최고 전력밀도는 $610mW/m^2$이었으며, 전극간 거리가 가깝고 산화전극의 표면적이 작을수록 전기발생에 효과적임을 알 수 있었다.

• 한국버섯학회지
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• 제10권4호
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• pp.244-248
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• 2012

팽이버섯 수확후배지의 사료화에 가장 적합한 저장법을 제시하기 위하여 미생물과 개미산을 처리한 팽이버섯 수확후배지를 퇴적, 뒤집기, 비닐피복 등의 방법으로 저장한 다음 미생물과 개미산 처리가 팽이버섯수확후배지의 저장성에 미치는 영향을 조사하였다. 저장기간에 따른 처리구별 팽이버섯 수확후배지의 외관적 성상변화를 종합해보면 저장기간 동안 모든 처리구에서 버섯 균사체가 버섯수확후배지의 표면에 우점하고 있었으며 호기적 조건보다는 혐기적 조건에서 저장성이 향상되었고 개미산 처리와 같은 화학적 처리법보다는 미생물을 접종한 처리구의 저장성이 향상됨을 확인할 수 있었다. 미생물과 개미산을 처리한 버섯수확후배지를 퇴적, 비닐피복, 뒤집기 등의 방법으로 8일 동안 저장하면서 버섯수확후배지의 온도, pH, 일반세균 수 등을 조사한 결과, 온도, pH, 일반세균 수는 미생물과 개미산 무처리구를 뒤집기한 경우에 가장 높게 나타났다.

• Journal of Pharmaceutical Investigation
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• 제31권4호
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• pp.233-239
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• 2001

Local drug delivery by using biocompatible polymers has been developed in the treatment of periodontitis for many years. In the field of dental therapy, doxycycline is usually a first choice because of its broad-spectrum antibiotic activity. The strip releases antibiotics for a week, and the polymer should be degradable after a week. In this study, we prepared and evaluated the chitosan strips and nanoparticle strips containing doxycycline hydrochloride, and studied their antiacterial activity, dissoultion, and degrability in vitro. The weight of cast strip containing a 5 mg of doxycycline hydrochloride and a 45 mg of chitosan polymer was $57.67{\pm}0.17\;mg$. The release rate of doxycycline hydrochloride from the strip was measured by HPLC. The drug released from chitosan strip and nanoparticle strip was shown to be $50\;{\mu}g/mL$ in first 24 hours. In antibacterial test showed growth inhibitory activity after 24 hrs anaerobic incubation. In vitro degradability showed demolished weight of $93.74{\pm}0.08%$ chitosan strip, $82.48{\pm}1.29%$ chitosan nanoparticle strip, $2.47{\pm}1.99%$ polycarprolactione strip (control). These results showed that, with this doxycycline hydrochloride strip, it is feasible to obtain a sustained release of the drug within the periodontal pocket for seven days which may be improve for local drug delivery system for treatment of periodontal disease.

• 한국식품과학회지
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• 제30권1호
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• pp.168-174
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• 1998

이 연구는 발효유 제조시 사용되는 Lactobacillus acidophilus NCFM이 생산하는 lactic acid의 생성변이를 조사하므로써 발효유 제조시 D(-)-lactic acid의 함량을 최소화하고 보존 중의 D(-)-lactic acid의 함량도 최소화하므로써 보다 인체에 유익한 발효유의 제조를 위한 기초적인 정보를 제공하기 위하여 실시되었으며, 그 결과는 다음과 같다. 발효온도는 $37^{\circ}C$에서 산생성이 가장 우수하였으며, D(-)-lactic acid의 비율도 가장 낮았다. 보존온도에 따른 변이에서는 저온에서 후산생성도 적었으며, D(-)-lactic acid의 비율도 가장 낮았다. 또한 처리에 따른 산생성에서는 호기상태에서 산생성이 가장 우수하였으며, D(-)-lactic acid의 함량이 가장 낮았다.

• 대한환경공학회지
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• 제31권2호
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• pp.139-146
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• 2009

본 연구에서는 두부공장에서 발생된 폐수를 이용한 생물학적 수소생성 특성과 미생물의 군집 변화를 살펴보았다. 두부 폐수는 산 또는 알카리 조건에서 전처리 된 후 수소생성량을 비교 하였으며, 산처리와 열처리를 병행하여 전처리 하였을 때 가장 왕성한 수소생산을 보였으며, Gompartz 방정식을 이용한 수소가스 발생량($P_h$)은 약 661.01 mL이고 최대 수소 생성율($R_h$)은 12.21 mL/g dry wt biomass/hr 이였다. 16S rDNA의 PCR-DGGE 결과 대부분 군집은 Streptococcus sp. 미생물로 규명되었으며 수소생성에 기여도가 큰 미생물은 Streptococcus gallolyticus sub sp.으로 판단되었다.

• 한국환경과학회지
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• 제8권1호
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• pp.107-113
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• 1999

A new biological nutrient removal system combining $A^2/O$ process with fixed film was developed in this work and the characteristics of denitrification were especially investigated in the combined fixed film reactor(CFFR). Media was added in the anaerobic, anoxic and aerobic reactors, respectively. Tests were made to establish the effluent level of $NO_x-N$, COD, DO and nitrite effects on $NO_x-N$ removal in the CFFR by decreasing hydraulic retention time (HRT) from 10.0 to 3.5 hours and by increasing internal recycle ratio form 0% to 200%. The influent was synthesized to levels similar to the average influent of municipal wastewater treatment plants in Korea. SARAN media with a porosity of 96.3% was packed 40% / 130% / 25% based on its reactor volume, respectively. It was found that COD rarely limited dentrification in the anoxic reactor because of high $C/NO_x/-N$ ratio in the anoxic reactor, while DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent inhibited denitrification in the anoxic reactor. It was proved that the critical points of DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent were 0.15mg/L and 10%, respectively. As the internal recycle ratio increased, DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent increased. Especially, at the condition of internal recycle ratio, 200%, DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent exceeded the critical points of 0.15mg/L and 10%, respectively. Then, denitrification efficiency considerably decreased. Consequently, it was represented that the control of DO concentration in the anoxic reactor and $NO_2-N/NO_x/-N$ from the aerobic effluent can assure effective denitrification.

• Journal of Microbiology
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• 제43권4호
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• pp.319-324
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• 2005

Estuarine sediments are frequently polluted with hydrocarbons from fuel spills and industrial wastes. Polycyclic aromatic hydrocarbons (PAHs) are components of these contaminants that tend to accumulate in the sediment due to their low aqueous solubility, low volatility, and high affinity for particulate matter. The toxic, recalcitrant, mutagenic, and carcinogenic nature of these compounds may require aggressive treatment to remediate polluted sites effectively. In petroleum-contaminated sediments near a petrochemical industry in Gwangyang Bay, Korea, in situ PAH concentrations ranged from 10 to 2,900 ${\mu}g/kg$ dry sediment. To enhance the biodegradation rate of PAHs under anaerobic conditions, sediment samples were amended with biostimulating agents alone or in combination: nitrogen and phosphorus in the form of slow-release fertilizer (SRF), lactate, yeast extract (YE), and Tween 80. When added to the sediment individually, all tested agents enhanced the degradation of PAHs, including naphthalene, acenaphthene, anthracene, fluorene, phenanthrene, fluoranthene, pyrene, chrysene, and benzo [a] pyrene. Moreover, the combination of SRF, Tween 80, and lactate increased the PAH degradation rate 1.2-8.2 times above that of untreated sediment (0.01-10 ${\mu}g$ PAH/ kg dry sediment/day). Our results indicated that in situ contaminant PAHs in anoxic sediment, including high molecular weight PAHs, were degraded biologically and that the addition of stimulators increased the biodegradation potential of the intrinsic microbial populations. Our results will contribute to the development of new strategies for in situ treatment of PAH-contaminated anoxic sediments.

• 한국초지조사료학회지
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• 제41권3호
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• pp.176-182
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• 2021

Ensiling is the most preferred technology to preserve the silage quality with high nutrients by the presence of lactic acid bacteria. In this study, lactic acid bacteria RJ1 and S22 were used to make the silages from different leguminous plants such as alfalfa, hairy vetch and red clover. Experimental groups were divided into control and LAB inoculated groups. LAB inoculated group; all legumes treated with a mixture of RJ1 and S22 and made an anaerobic condition for 45d. Without the addition of LAB considered the control group. The results showed that the lactic acid content was higher in all silages in response to LAB treatment and acetic acid content was slightly increased except red clover by LAB compared to control silages. A poor silage quality marker butyric acid was reduced all legume silages in response to LAB inoculation than control silages. The organic acid is closely associated with microbial population experimental silages. We noted that higher LAB and lower yeast were found in the silage in response to LAB treatment. The contents of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and total digestible nutrient (TDN) were not altered significantly between control and LAB treated silages. Overall data suggested that the inclusion of additional LAB potentially enhance the silage quality and preserved the nutrients for long period.

• 대한본초학회지
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• 제28권3호
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• pp.45-51
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• 2013

Objectives : This study was conducted to measure the antioxidative and antimicrobial activities of water- and ethanol-extracts from Betula platyphylla var. japonica, Punica granatum and Rhus javanica against various species of anaerobic bacteria. Methods : In order to evaluate the antioxidative and antimicrobial activities of water- and ethanol-extracts, DPPH radical scavenging and superoxide dismutase (SOD)-like activities were measured in various species such as Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Propionibacterium acnes that induce skin inflammation. Also the total amount of phenol in each water- and ethanol-extract was measured to identify its role in the antioxidative and antimicrobial activities of water- and ethanol-extracts from Betula platyphylla var. japonica, Punica granatum and Rhus javanica. The antibacterial activity of the extracts was measured by confirming the lowest concentrations in disk diffusion and minimum inhibitory concentration (MIC) tests. Results : It was observed that RJE (Rhus javanica-EtOH extracts) show the highest content of total phenol. In addition, for RJE the total phenol content was higher from samples taken from domestic sources than from samples taken from foreign sources. DPPH radical scavenging activity was increased by treatment with PGE (Punica granatum-EtOH extracts), RJE and RJW (Rhus javanica-water extracts). It was observed that SOD-like activity was highest in the treatment with PGE. All of the extracts showed antimicrobial activity on S. epidermidis, S. aureus, P. acnes and E. coli, including those from Punica granatum, and it was noted that the activity was higher with RJE than with RJW. Conclusions : These results provide evidence that ethanol extracts of Punica granatum and Rhus javanica may have a beneficial role as antioxidants and antibiotics. Extracts from domestic samples of Betula platyphylla var japonica appeared to have a greater efficacy than extracts from foreign samples.