• Journal of Microbiology
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• 제45권2호
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• pp.171-174
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• 2007

The growth stimulation of wild plants by several bacterial species showing plant growth-promoting capabilities was examined in a barren lakeside area at Lake Paro, Korea. Microbial numbers and activities in the field soil were monitored for 73 days after inoculation of the bacteria. The acridine orange direct counts for the total soil bacterial populations ranged between $2.0-2.3{\times}10^{9}\;cells/g$ soil and $1.4-1.8{\times}10^{9}\;cells/g$ soil in the inoculated and uninoculated soils, respectively. The numbers of Pseudomonas spp., which is known as a typical plant growth-promoting rhizobacteria, and the total microbial activity were higher in the inoculated soil compared to those in the uninoculated soil. The average shoot and root lengths of the wild plants grown in the inoculated soil were 17.3 cm and 12.4 cm, respectively, and longer than those of 11.4 cm and 8.5 cm in the uninoculated soil. The total dry weight of the harvested wild plants was also higher in the inoculated soil (42.0 g) compared to the uninoculated soil (35.1 g). The plant growth-promoting capabilities of the inoculated bacteria may be used for the rapid revegetation of barren or disturbed land, and as biofertilizer in agriculture.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
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• pp.137-141
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• 1998

A chemical has been aging in soil environment is more less bioavailable than freshly added chemical. The amount of bioavailability of the aged chemical is different by bacterial strains. The difference could be depend on physiochemical properties of each strain. Phenanthrene was employed as an aged chemical. Seven bacteria were isolated from activated sludge and petroleum disposed soil. These strains were able to degrade phenanthrene and to grow using phenanthrene as a sole carbon source. According to the result of materialization and chemical extraction experiment, the bioavailable amount of aged phenanthrene which has been aged in Lima loam is different by each bacteria. Several physiochemical properties of each strain were tested to certify correlation with their different amount of bioavailability.

• 한국토양비료학회지
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• 제29권1호
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• pp.67-73
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• 1996

식물(植物) 생육촉진(生育促進) 유용미생물(有用微生物)을 지리산 일대의 침엽수와 활엽수 밑의 부엽토(腐葉土)에서 선발하고, 고추묘에 접종하여 묘의 생장에 미치는 효과를 조사한 결과는 다음과 같다. 1. 분리된 8종의 균주를 동정한 결과 Micrococcus sp., Bacillus subtilis, Enterobacter agglomerans, Bacillus megaterium, Pseudomonas putida, Pseudomonas fluorescens, Xanthomonas maltophilia, Staphylococcus xylosus등 8종의 균주가 동정되었다. 2. 8종의 혼합균주 처리구의 고추묘의 초장(草長)은 무처리구에 비해 처리 10일 이후, 엽수(葉數)는 44일 이후부터 생육이 크게 진전되었다.

• 한국토양비료학회지
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• 제49권4호
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• pp.381-387
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• 2016

The scientific information on the microbial differentiation according to the changes in chemical properties of paddy soil in reclaimed tidal lands is not enough to understand the reclamation processes. The changes in microflora based on the chemical properties of paddy soils at the same sites of reclaimed tidal lands (21 samples from Nampo, Ewon, Sukmoon and Shihwa sites) were investigated in 2013 and 2015. In general, organic matter in paddy soils increased whereas pH decreased with the reclamation time. The electrical conductivities (EC) of soil samples were closely related to the exchangeable $Na^+$. With an increases in EC of paddy soils from 0.39 to $48.9dS\;m^{-1}$, the ratios (%) of halotolerant and halophilic bacteria to mesophilic bacteria proportionally increased from 0.2% to 102,000%. The population of halotolerant and halophilic bacteria in total microflora was also differentiated with the changes in EC of the same sites from reclaimed tidal soils within 2 years. The population of mesophilic bacteria decreased with an increase in EC above $5dS\;m^{-1}$. The microflora including halotolerant and halophilic bacteria could be a candidate as a biological parameter in evaluating the reclamation processes in addition to the chemical index of EC.

• 한국재료학회지
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• 제32권3호
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• pp.168-179
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• 2022

Microbiologically Influenced Corrosion (MIC) occurring in underground buried pipes of API 5L X65 steel was investigated. MIC is a corrosion phenomenon caused by microorganisms in soil; it affects steel materials in wet atmosphere. The microstructure and mechanical properties resulting from MIC were analyzed by OM, SEM/EDS, and mapping. Corrosion of pipe cross section was composed of ① surface film, ② iron oxide, and ③ surface/internal microbial corrosive by-product similar to surface corrosion pattern. The surface film is an area where concentrations of C/O components are on average 65 %/16 %; the main components of Fe Oxide were measured and found to be 48Fe-42O. The MIC area is divided into surface and inner areas, where high concentrations of N of 6 %/5 % are detected, respectively, in addition to the C/O component. The high concentration of C/O components observed on pipe surfaces and cross sections is considered to be MIC due to the various bacteria present. It is assumed that this is related to the heat-shrinkable sheet, which is a corrosion-resistant coating layer that becomes the MIC by-product component. The MIC generated on the pipe surface and cross section is inferred to have a high concentration of N components. High concentrations of N components occur frequently on surface and inner regions; these regions were investigated and Na/Mg/Ca basic substances were found to have accumulated as well. Therefore, it is presumed that the corrosion of buried pipes is due to the MIC of the NRB (nitrate reducing bacteria) reaction in the soil.

• 한국토양비료학회지
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• 제34권6호
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• pp.387-393
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• 2001

벼 생산력과 환경보전을 상호 보완할 수 있는 지속농업 체계를 구축하는데 필요한 기초자료를 제공함과 아울러 관리기술을 개발하고자 경남지역에 산재된 논토양 487개소의 화학성과 미생물상을 연구한 결과는 다음과 같다. 논토양의 평균 개체수는 호기성 세균 $298{\times}10^5$($4{\sim}3000{\times}10^5$), 사상균 $63{\times}10^3$($2{\sim}441{\times}10^3$), 방선균 $19{\times}10^5$($0.2{\sim}1250{\times}10^5$), Bacillus sp. $53{\times}10^4$($4{\sim}890{\times}10^4$), Pseudomonas sp. $198{\times}10^4$($4{\sim}1724{\times}10^4$)$CFU\;g^{-1}$였다. 토양 미생물 균수는 남부지방이 북부지방보다 많았으며 평균 B/F비는 473 이었다. 토양의 점토함량이 증가할수록 호기성 세균, 방선균, Pseudomonas sp.의 균수는 감소하였다. B/F비는 사양토와 식양토에서 각각 1554, 1144로 높았고 Bacillus sp./fungi 비율은 식양토, 양토에서 각각 11, 10 으로 높았다. 지형별 미생물 균수 변이는 하해혼성평탄지에서 호기성 세균과 Bacillus sp./fungi 비율이 높았으며 토양유형별로는 습답에서 미생물의 균수가 낮았다. 토양 무기성분중 EC, $P_2O_5$, K, Ca, $NO_3-N$ 함량은 호기성 세균, 방선균, 사상균, Bacillus sp., Pseudomonas sp. 균수와 정의상관이 있었고 토양 유기물과 Mg 함량은 호기성 세균, 방선균, 사상균, Bacillus sp.와 정의상관이 있었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제9권2호
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• pp.41-47
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• 2004

This research in the degradation of polychlorinated biphenyls(PCB) has focussed on the use of experimental enrichment cultures to obtain PCB-deading communities and identification of PCB-degrading bacteria accor야ng to pure culture. During 180 days, enrichment culture was performed to obtain PCB-degrading bacteria and initial concentration was injected 1.6 ppm,0.7 ppm, respectively. After 180 days of enrichment culture, PCBs was removed 80-87% and 57-71%. Biodegradation of PCBs was studied according to dominated PCB-degrading bacteria. Biodegraddation of PCBs was 80% in initial concentration of PCBs for 20days, enrichment cultured PCB-degrading bacteria was isolated by pure culture and it was verified to Pseudoxanthomonas sp.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.122-124
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• 2002

The removal capacity of zero-valent iron for Cr(Ⅵ) was evaluated using batch kinetic tests. The rate constants for zero-valent iron dramatically increased as initial Cr(Ⅵ) concentration decreased. Generally, the reaction rates of Cr(Ⅵ) with zero-valent iron were faster than that of a biotic degradation of Cr(Ⅵ), and furthermore the reaction rates were inversely proportional to the initial Cr(Ⅵ) concentrations. After certain reaction time elapsed. no further decrease of Cr(Ⅵ) was observed, indicating a loss of iron reactivity. The loss of iron reactivity was primarily due to the passivation of iron surfaces with iron-Cr precipitates, but the reactivity of iron was recovered by adding iron-reducing bacteria. Even though the addition of bacteria itself removed Cr(Ⅵ), the combination of iron-reducing bactera and oxidized iron significantly enhanced the reaction rate for Cr(Ⅵ) removal. The results from column tests also confirmed that the innoculation of iron-reducing bacteria to the column containing completely oxidized iron partially enhanced the recovery of the iron reactivity.

• 한국토양비료학회지
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• 제46권6호
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• pp.474-481
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• 2013

Understanding the microbial community structure of agricultural soils is important for better soil management in order to improve soil quality. Phospholipid fatty acid analysis has been popularly used in determining the microbial community structure in different ecosystems. The microbial community structure of paddy soil under long-term fertilizer treatments was investigated after 45 years using PLFA analysis. Treatments were control (no fertilization, Con), compost (COM), NPK, NPK+compost (NPKC), PK, NK, and NP. Soil chemical properties were mainly affected by the addition of compost and inorganic P fertilizer. Total nitrogen and organic matter contents were significantly higher in treatments with compost while available $P_2O_5$ and exchangeable calcium were significantly higher in treatments with added inorganic P fertilizer. It was found that microbial communities were responsive to the different fertilizer treatments. PLFA results showed that the soils were dominated by gram-negative bacteria, followed by the actinomycetes, then gram-positive bacteria, and fungi. Principal component analysis of the soil chemical properties and PLFA composition proved to be a more reliable tool because it was more responsive to the changes in soil chemical properties.

• 한국토양비료학회지
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• 제17권3호
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• pp.299-306
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• 1984

난분해성(難分解性) 유기염소계(有機鹽素系) 살균제(殺菌劑) 및 살충제(殺蟲劑)의 다량(多量) 연용(連用)이 밭토양(土壤)의 미생물상(微生物相)에 미치는 영향(影響)을 구명(究明)코자 TPN(Tetrachloroisophthalonitrile), HCH(Hexachlorocyclohexane) 및 퇴비(堆肥)를 단독(單獨) 그리고 혼합투여(混合投與)한 시험포장(試驗圃場)에서 2년간(年間)에 걸쳐 미생물상(微生物相)의 경시적(經時的)인 변동(變勳)을 조사(調査)하여 다음과 같은 결과(結果)를 얻었다. 1. HCH의 투여(投與)는 방선균수(放線菌數)의 변화(變化)에는 영향(影響)하지 않았고 포자형성세균수(胞子形成細菌數)를 약간(若干) 저하(低下)시켰으나 전세균(全細菌), 그람음성세균(陰性細菌) 및 사상균수(絲狀菌數)를 어느 정도(程度) 증가(增加)시켰다. 2. TPN의 투여(投與)는 전세균(全細菌), 그람음성세균(陰性細菌), TPN내성세균(耐性細菌) 및 TPN내성(耐性)그람음성세균(陰性細菌)의 수(數)를 현저(顯著)하게 증가(增加)시킨 반면(反面), 사상균(絲狀菌), 방선균(放線菌) 및 포자형성세균(胞子形成細菌)의 수(數)를 격감(激減) 시켰다. 3. TPN HCH의 혼합투여(混合投與)는 각 농약(農藥)의 단독투여시(單獨投與時) 결과(結果)의 합(合)으로 나타나 전세균(全細菌), 그람음성세균(陰性細菌), TPN내성세균(耐性細菌) 및 TPN내성(耐性)그람음성세균(陰性細菌)의 수(數)를 증가(增加)시켰고 사상균(絲狀菌), 방선균(放線菌) 및 포자형성세균(胞子形咸細菌)의 수량(數量)을 감소(減少)시켰다. 4. 퇴비(堆肥)와 이들 농약(農藥)과의 혼합시용(混合施用)은 이들 농약(農藥)의 투여(投與)에 의한 토양미생물수(土壤微生物數)의 증가(增加)를 촉진(促進)시켰고 감소(減少)를 완화(緩和)시켜 전세균(全細菌) 및 그람음성세균수(陰性細菌數)의 증가(增加) 정도(程度)를 강화(强化)시켰고 사상균(絲狀菌), 방선균(放線菌) 및 포자형성세균수(胞子形成細菌數)의 감소정도(減少程度)를 약화(弱化)시켰다. 5. TPN의 연용(連用)에 의하여 TPN내성세균(耐性細菌) 특(特)히 TPN내성(耐性)그람음성세균(陰性細菌)의 집적(集積)이 현저(顯著)하였다.