• Korean Journal of Microbiology
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• v.37 no.1
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• pp.80-84
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• 2001

Vertical and temporal variations of active and total bacterial abundance were monthly estimated in Lake Soyang from April 1999 to January 2000. The number of total and respiring bacteria was determined directly under microscope by AODC and CTC methods, respectively. The number of total and active bacteria varied from $2.1{\times}10^5 to 3.1{\times}10^6 $,$cells{\cdot}ml^{-1}$ and $1.8{\times}10^4 to 8.0{\times}10^5 $,$cells{\cdot}ml^{-1}$, respectively. The proportions of respiring bacteria to total cell ranged from 3.7 to 44.2% : The proportions was the highest in November 1999 and the lowest in December 2000. The specific activity of${\beta}$-glucosidase divided by total bacteria was$1.6{\times}10^5\;amol{\cdot}cell^{-1}{\cdot}hr^{-1}$in August and$1.4{\times}10^5\;amol{\times}cell^{-1}{\times}hr^{-1}$in September while the specific activity divided by CTC active bacteria was about$3.6{\times}10^5\;amol{\cdot}cell^{-1}{\cdot}hr^{-1},\;24.0{\times}10^5\;amol{cdot}cell^{-1}{cdot}hr^{-1}$. The specific activity of active bacteria in September was 6.7 times higher than that of August. By these data of active bacteria, the new information of aquatic ecosystem was unveiled.

• Korean Journal of Microbiology
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• v.49 no.4
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• pp.321-327
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• 2013

In the present work, the reactors that harbor bacterial biofilms including ammonia-oxidizing bacteria (AOB) and heterotrophic bacteria were treated with a continuous dose of chlorite ($0.66{\pm}0.01mg/L$) either with or without monochloramine at $1.77{\pm}0.03mg/L$. Both chlorite alone and combined chlorite-monochloramine applications effectively reduced biofilm and bulk AOB levels to near or below the detection limit ($0.6MPN/cm^2$ and 0.2 MPN/ml). The combined chlorite-monochloramine application exhibited greater AOB inactivation than chlorite alone. Unlike AOB, heterotrophic plate count (HPC) was unaffected by chlorite alone. In contrast to chlorite-only application, a combination of chlorite and monochloramine resulted in a significant reduction in HPC levels with log reductions of 3.1 and 3.0 for biofilm and bulk water, respectively. The results demonstrate that the combined chlorite-monochloramine application can provide an effective treatment for the inhibition of AOB and heterotrophic bacteria in a drinking water distribution system.

• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.1
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• pp.1-11
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• 1996

The effect of seeding on the thermophilic composting of food waste was investigated with selected strains of yeast, thermophilic bacteria and the mixed strains of yeast and bacteria in the lab-scale composter at $50^{\circ}C$. The results demonstrated that in all case the growth of yeasts preceded the growth of thermophilic bacteria by one or two days. The seeding of bacteria alone was ineffective for thermophilic bacterial development and the rapid increase of total thermophilic bacterial count was obtained by mixed seeding of yeasts and bacteria. Moreover, the bacterial growth was accelerated by the addition of yeasts alone. It was revealed that the yeasts removed organic acids from the food waste at the initial period and consequently induced the growth of thermophilic bacteria. The results presented in this paper indicate the indispensable role of yeasts for thermophilic process of food waste composting.

• Journal of Wetlands Research
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• v.7 no.2
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• pp.37-52
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• 2005

Vertical distribution of bacterial population and activities were compared between the muddy and sandy sediment of the tidal flat located in southern area of Ganghwa Island. The average of bacterial number and activities in mud flat was slightly higher than that in sand flat. Bacterial number was markedly increased at the sandflat during the investigation period, which seemed to be the result of increase of mud content. The number and activities of microorganisms in mudflat was comparable to that of the mangrove sediments. There was no differences in bacterial number with the depth, but the aminopeptidase activity and bacterial productivity were decreased markedly within 3~5cm depth of sediment due to the availability of carbon sources and molecular oxygen in pore water. The number and activities of microorganisms in mudflat did not correlated with the distribution of benthic microalgae; however, those in sand flat were closely correlated with the distribution of benthic microalgae. The distribution of marsh plant in the mudflat area might be the reason of the difference.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.5
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• pp.314-324
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• 2011

Algal biomass cultivated by wastewater is potentially useful resource for biodiesel production. However, little is known about algal nutrient metabolism and microbial interaction with bacteria under real municipal wastewater condition. In this work, we characterized nitrogen and phosphorus removals of municipal wastewater by a representative wastewater-growing algal population. Ankistrodesmus gracilis SAG 278-2, and analyzed its ecological interaction with wastewater bacterial communities. Compared to wastewater sludge itself, algal-bacterial co-culture improved nutrient removal. According to bacterial community analysis with 16S rRNA genes, a selective and dominant growth of a Unclassified Alcaligenaceae population resulted from algal growth in the algal-bacterial co-culture. The selectively stimulated bacterial population is phylogenetically close to Alcaligenes faecalis subsp. 5659-H, which is known to be co-present interact with algae in aquatic environment. These findings suggest that algal growth/metabolism may have effects on selection of a specific bacterial population in algal-bacterial co-cultures that can efficiently remove nutrients from municipal wastewater.

• KSBB Journal
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• v.20 no.5 s.94
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• pp.387-391
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• 2005

Totally 16,299 conservative genes, commonly found in 13 thermophilic and hyperthermophilic bacteria, were analyzed. All genes were belong to W 67 COGs (clusters of orthologous groups of proteins). COGs related to protein metabolism were 80 among 167 COGs. Conservative genes were not limited only thermophiles and hyperthermophiles, meaning thermal stability is independent of specific protein. However reverse gyrase was only found in all hyperthermophilic archaebacteria and eubacteria, meaning DNA stability is important in hyperthermophiles. Hyperthermophilic eubacteria and thermophilic archaebacteria had different position between phylogenetic tree of gene content and 165 rRNA gene. Thermophilic archaebacteria hyperthermophilic eubacteria and archaebacteria had similar values by the statistical analysis of distance values with 167 COGs in each organism.

• Journal of Life Science
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• v.2 no.3
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• pp.175-179
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• 1992

광조사시에 수소를 생산하는 미생물로는 녹조류, 남조류 그리고 광합성세균이 알려져 있으며, 이 중에서 남조류와 광합성세균이 실용적인 수소생산에 유망시되고 있다. 광합성세균은 광학계 II가 결여되어 물분해능이 없으나 유기화합물을 전자공여체로하여 남조보다 훨씬 빠른 속도로 수소를 생산하며, 생산가스는 약간의 이산화탄소 외에는 거의 순수한 수소여서 그대로 연료로 사용할 수 있는 장점을 지닌다. 본고에서는 공합성세균에 의한 수소생생의 연구현황과 문제점에 대해 다루었다. 광합성세균에 의한 수소생산의 실용화를 위해서는 균체의 수소생산성 향상 및 활성의 유지, 원료문제 및 암모니아에 의한 수소 생산의 억제문제, 적합한 배양조개발과 균체의 이용방안 등에 관련된 제분제의 해결이 필요하다. 광합성세균의 수소생산성 향상을 위해서는 자연계로부터 보다 고활성균주의 탐색과 아울러 유전적인 개량이 병행되어야한다.

• Research in Plant Disease
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• v.6 no.1
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• pp.15-18
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• 2000

A new bacterial disease was found on leaves of Kalanchoe blossfeldiana plant grown under vinyl-house condition in winter of 1998 in Taejeon. the first symptoms of the disease are the appearance of the water-soaked and light brown spots. Later they become soft rot with brown color. Causal bacteria were isolated from diseased tissues and the same symptoms as the natural infection were developed on Kalanchoe blossfeldiana leaves by needle-prick inoculation. The causal bacterium was identified Erwinia hervicola by its bacteriological characteristics. This is the first reported of this bacterium to occur on kalanchoe blossfeldiana plant in Korea. Therefore, we proposed to name the diseases as \"bacterial soft rot of Kalanchoe blossfeldiana\" by E. herbiocla.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.120-120
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• 2022

장내세균의 구성과 각종 질환의 상관관계에 대한 연구가 활발히 수행되고 있다. 대장관련 질환 뿐 아니라, 당뇨, 비만 등 대사성 질환, 심지어 정신질환에까지 장내세균 구성의 영향이 미치는 것으로 밝혀졌다. 이에 다양한 천연 소재를 활용하여 각종 동물질환모델에서 생리활성을 검토할 때, 장내세균의 구성을 분석하여 그 상관관계를 밝힐 필요가 있다. 장내세균의 구성에 따라 질환의 양상이 달라질 수 있으며, 치료에 영향을 줄 수 있다. 동물실험을 수행할 때에도 실험동물 간 장내세균의 구성이 다르면 질환의 유도 또는 천연소재에 의한 치료 패턴이 달라질 수 있음을 가정하여 본 연구를 수행하였다. 본 연구에서는 EtOH와 LPS를 이용하여 간장해 동물모델을 구축하고, 장내세균 구성을 T-RFLP법으로 분석하여 그 상관관계를 검토하였고, tracheloside 등의 천연물을 투여함으로써 성분의 대사 패턴을 확인하였다. 이 결과는 천연소재의 간장해 개선 연구를 수행하기 위한 기초 결과로 활용될 수 있다.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.518.1-518
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• 1986

광합성 세균의 수소생성 기작에 대한 연구의 일환으로 광합성 세균에서 생성되는 색소의 성분을 조사하였다. 분리한 광합성 세균 K-7은 수소생성능이 뛰어난 균주로 조사된 홍색 비유황세균으로서 생리, 형태 및 배양학적 조사에 의하여 Rhodopseudomonas spheroides로 분류하였다. Type culture인 Rhodopseudomonas spheroides NCIB 8253과 비교 연구하였으며, SEM(Scanning Electron Microscope)하에서 기존균주와 분리균주의 형태학적인 특징을 확인하였다. 군 동정의 주요열쇠가 되는 색소성분을 조사한 결과, 균주 K-7에서 추출된 carotenoids로는 spheroidene의 산화형태인 OH-spheroidenone이 주성분이었고, Neurosporene, Lycopene, Anhydro- rhodovibrin, Rhodovibrin등이 동정되었다.