• Food Science and Biotechnology
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• 제18권1호
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• pp.137-142
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• 2009

One of the most important aspects of conducting this microbial risk assessment (MRA) is determining the model in microbial behaviors in food systems. However, to fully these modeling, large expenditures or newly laboratory experiments will be spent to do it. To overcome these problems, it has to be considered to develop the new strategies that can be used data in the published literatures. This study is to show whether or not the data set from the published experimental data has more value for modeling for MRA. To illustrate this suggestion, as example of data set, 4 published Salmonella survival in Cheddar cheese reports were used. Finally, using the GInaFiT tool, survival was modeled by nonlinear polynomial regression model describing the effect of temperature on Weibull model parameters. This model used data in the literatures is useful in describing behavior of Salmonella during different time and temperature conditions of cheese ripening.

• 한국농공학회논문집
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• 제49권2호
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• pp.87-97
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• 2007

The aim of this study was to compare crop contamination between two irrigation methods using microbial-contaminated water. The effect of relative humidity on microbial survival of the three indicator microorganisms was also investigated. Escherichia coli ATCC 25922, Clostridium perfringens ATCC 3624, and coliphage PRD1 were applied to irrigation water to grow cantaloupe, lettuce, and bell pepper. Half of the sixteen plots were subsurface drip irrigated (SDI) and the other half were furrow irrigated (FI). Two relative humidity levels were controlled at 15-65 % and 55-80 % for the dry and humid condition experiments, respectively. Samples of produce, surface soil, and subsurface soil at a depth of 10 cm were collected over a two-week period following the application of the study microorganisms. Overall, greater contamination of both produce and soil occurred in the FI plots. For the SDI plots, preferential water paths and resulting water appearance on the seed beds seemed to be responsible for produce contamination. Relative humidity levels did not appear to affect microbial survival in soil. PRD 1 showed lower inactivation rates than 5. coli in both dry and humid conditions. C. perfringens did not experience significant inactivation over the experimental period, suggesting this microorganism can be an effective indicator of fecal contamination.

• Journal of Microbiology and Biotechnology
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• 제22권1호
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• pp.126-132
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• 2012

A cellulose-degrading composite microbial system containing a mixture of microbes was previously shown to demonstrate a high straw-degrading capacity. To estimate its potential utilization as an inoculant to accelerate straw biodegradation after returning straw to the field, two cellulose-degrading composite microbial systems named ADS3 and WSD5 were inoculated into wheat straw-amended soil in the laboratory. The microbial survival of the inoculant was confirmed by a denaturing gradient gel electrophoresis (DGGE) analysis, whereas the enhancement of straw degradation in soil was assessed by measuring the mineralization of the soil organic matter and the soil cellulase activity. The results indicated that most of the DGGE bands from ADS3 were detected after inoculation into straw-amended autoclaved soil, yet only certain bands from ADS3 and WSD5 were detected after inoculation into straw-amended non-autoclaved soil during five weeks of incubation; some bands were detected during the first two weeks after inoculation, and then disappeared in later stages. Organic matter mineralization was significantly higher in the soil inoculants ADS3 and WSD5 than in the uninoculated controls during the first week, yet the enhanced degradation did not persist during the subsequent incubation. Similar to the increase in soil organic matter, the cellulase activity also increased during the first week in the ADS3 and WSD5 treatments, yet decreased during the remainder of the incubation period. Thus, it was concluded that, although the survival and performance of the two inoculants did not persist in the soil, a significant enhancement of degradation was present during the early stage of incubation.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.139-139
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• 2022

Nature-based solutions (NBS) involved conservation or rehabilitation of natural ecosystems or the creation of natural processes in modified or artificial ecosystems to mimic natural processes for the improved management of water (UN-Water, 2018). This study investigated the relationship between microbial presence and survival to the pollutant treatment performance of seven different stormwater NBS managing urban stormwater runoff. In this study, seven different stormwater nature-based solution (NBS) was investigated to identify the relationship of microbial community to the pollutant removal performance of stormwater NBS. Based on this study, Proteobacteria was found to be the most dominant microorganism for all stormwater NBS and IS followed by Acidobacteria and Actinobacteria. Acidobacteria, Actinobacteria, Chloroflexi, Gemmatimonadetes, WS3, and AF234118_p were found to have high positive correlation to most pollutant removal efficiency of different stormwater NBS (r-value: 0.62 to 0.68). Using Proteobacteria and Acidobacteria count in stormwater NBS, equations predicting pollutant removal performance were also developed and may be used in minimizing the cost for stormevent monitoring to identify the pollutant removal performance of stormwater NBS.

• 한국환경농학회지
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• 제40권3호
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• pp.194-202
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• 2021

BACKGROUND: Towards achievement of sustainable agriculture, using microbial inoculants may present promising alternatives without adverse environmental effects; however, there are challenging issues that should be addressed in terms of effectiveness and ecology. Viability and stability of the bacterial inoculants would be one of the major issues in effectiveness of microbial pesticide uses, and the changes within the indigenous microbial communities by the inoculants would be an important factor influencing soil ecology. Here we investigated the stability of the introduced bacterial strains in the soils planted with barley and its effect on the diversity shifts of the rhizosphere soil bacteria. METHODS AND RESULTS: Two different types of bacterial strains of Bacillus thuringiensis and Shewanella oneidensis MR-1 were inoculated to the soils planted with barley. To monitor the stability of the inoculated bacterial strains, genes specific to the strains (XRE and mtrA) were quantified by qPCR. In addition, bacterial community analyses were performed using v3-v4 regions of 16S rRNA gene sequences from the barley rhizosphere soils, which were analyzed using Illumina MiSeq system and Mothur. Alpha- and beta-diversity analyses indicated that the inoculated rhizosphere soils were grouped apart from the uninoculated soil, and plant growth also may have affected the soil bacterial diversity. CONCLUSION: Regardless of the survival of the introduced non-native microbes, non-indigenous bacteria may influence the soil microbial community and diversity.

• 한국식품위생안전성학회지
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• 제36권6호
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• pp.481-487
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• 2021

본 연구는 로메인 상추에서 병원성미생물이 생존과 생육의 특성을 분석하여 안전관리 정보를 확보하고자 실시하였다. 로메인 상추에서 분무 접종한 E. coli O157:H7은 72시간 배양 후 초기균수 보다 2.0 log CFU/g 수준으로 증가하여 생존 및 증식이 가능한 것으로 판단되었다. 상추 잎의 상처 유무에 따른 E. coli O157:H7은 배양 72시간 후 유의적 차이가 없었다. 상추 잎에 인위적인 상처에 내어 E. coli O157:H7을 접종하고 병원균의 분포를 조사한 결과 상처가 없는 상추는 표면이 매끄러워 균이 부착하지 못하거나 균수가 매우 낮았고, 상처가 있는 상추 잎은 거친 표면에 균이 밀집되어 상처를 통해 상추 내부로 침입하는 것으로 판단되었다. 병원성미생물의 상추 추출물 이용 여부는 10-100% 농도에서 배양 24시간 이후에 E. coli O157:H7 8.9 log CFU/mL, L. monocytogenes 8.6 log CFU/mL, P. carotovorum 8.8 log CFU/mL로 나타났다. 이는 병원성미생물과 식물병원균이 유사한 4 log CFU/g 이상의 증가율을 나타내어 미생물이 상추 추출물을 영양원으로 사용할 수 있는 것으로 판단되었다. 상추 추출물 0.1%에서 초기 접종 농도와 비교하여 E. coli O157:H7 2.7, L. monocytogenes 1.3, P. carotovorum 2.9 log CFU/mL 수준으로 증가하였다. 이에 따라 병원성 미생물의 최소생육농도는 0.1%보다 낮은 것으로 판단되었고, 상처를 통해 지속적으로 0.1% 수준의 상추 추출물이 병원성미생물에 제공되면 상추 내부에서도 생존 및 증식이 가능할 것으로 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제19권8호
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• pp.810-817
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• 2009

The effect of cryoprotectants (maltodextrin+glycerol) and cryoprotectants+antioxidant [ascorbic acid and/or butylated hydroxytoluene (BHT)] mixtures on the survival, electrolyte leakage, and lipid degradation of freeze-dried Weissella paramesenteroides LC11 during storage was investigated and compared with that of the control (cells without additives) over a 90-day storage period at 4 or $20^{\circ}C$ in glass tubes with water activity ($a_w$) of 0.23. The survival, electrolyte leakage, and lipid degradation were evaluated through colony counts, electrical conductivity, and thiobarbituric acid reactive substances (TBARS) content, respectively. The fatty acids composition was determined by gas chromatography, in both the total lipid extract and the polar lipid fraction, and compared with that of the control after the 90-day storage period. As the storage proceeded, increases in leakage value and TBARS content, as well as a decrease in viability, were observed. After 90 days of storage, the major fatty acids found in both the total lipid extract and the polar lipid fraction were palmitic (16:0), palmitoleic (16:1), stearic (18:0), oleic (18:1), linoleic (18:2), and linolenic (18:3) acids. The survival, leakage value, TBARS content and 18:2/16:0 or 18:3/16:0 ratio were the greatest for the protected strain held at $4^{\circ}C$. Cells with the cryoprotectants+BHT mixture showed the highest percentage of survival and 18:2/16:0 or 18:3/16:0 ratio in both lipid extracts, as well as the lowest leakage value and TBARS content after the 90-day storage period. Drying cells with the cryoprotectants+BHT mixture considerably slowed down polar lipid degradation and loss of membrane integrity, resulting in improved viability during storage.

• 생명과학회지
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• 제28권1호
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• pp.68-77
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• 2018

바이오제닉 아민 비생성 유산균의 선별을 위해 순창군에서 재배된 베리류 및 엑기스, 식초 등으로부터 42종의 유산균을 분리하였다. 분리주를 대상으로 세포외 효소 활성, 항균 활성, 항산화 활성과 같은 다양한 생리활성 분석을 실시하여 5종의 분리주를 1차 선별하였다. 분리주를 대상으로 바이오제닉 아민 생성 여부를 분석하여 최종적으로 SBB07을 선별하였고, 16S rRNA 염기서열 분석을 통해 Lactobacillus brevis SBB07로 명명하였다. SBB07의 프로바이오틱스 활용 가능성을 확인하기 위해 효소 생산 여부, 내산성, 내담즙성, 내열성, 항생제 내성을 조사하였고, pH 2.0에서의 내산성 및 0.5% oxgall을 함유한 내담즙성에서 각각 86% 이상과 54% 이상의 높은 생존율을 나타내었다. 또한 $60^{\circ}C$에서도 113% 이상의 생존율을 나타내어 내열성도 우수하며 다양한 항생제 내성을 갖는 것을 확인하였다. 프리바이오틱스 이용가능성을 확인한 결과에서는 GOS의 이용 능력이 가장 우수하였으며, FOS와 inulin의 이용 능력도 높게 나타났다. 따라서 SBB07은 세포외 효소 및 항균 활성이 우수하고, 내담즙, 내산성, 내열성 및 항생제 내성을 지니며 프리바이오틱스 기질 이용 능력도 우수한 프로바이오틱스 소재로 활용가능성이 높은 유산균으로 기대된다.

• 한국토양비료학회지
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• 제35권4호
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• pp.243-252
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• 2002

토양생태계는 정량화하기 어려운 다양한 규칙이 다중적으로 조화되어 끊임없이 변하고있어 어떤 현상을 획일적으로 평가하기 어렵다. 그러나, 미생물은 환경에 대한 감수성이 빨라 토양의 생물적인 특성 변화를 가장 먼저 나타내기 때문에, 미생물은 생태계의 가변적 변동상의 지표가 될 수 있다. 또한 토양에 생명력을 부여해주는 기능을 가지고 있어 토양미생물의 작용 및 기능 평가는 토양 건전성 관리에 있어 중요한 역할을 한다. 따라서 본 연구는 생물학적 토양 건전성 평가 지표요인 개발하고자 주요 모재별 미경지 토양의 생물학적 토양특성을 평가하고자 수행하였다. 주요 모재별 미경지 토양의 미생물 밀도는 현무암유래 토양에서 낮고 석회암유래 토양에서 높은 경향이었으나, 그람 음성균은 비슷한 수준을 유지하고 있었다. 토양 건조처리시 미생물의 생존율은 형광성 Pseudomonas속이 0.1%로 가장 낮았으나 고온성 Bacillus속과 호알카리성균은 90%이상으로 높았다. 토양미생물체량과 미생물 유fo 유기탄소량 간에는 정의 상관관계를 나타냈으며, 토양 건조처리 효과는 토양별 9.7~95.0% 범위로 평균 39.8%였다. 건토를 재습윤하였을 때 중온성 Bacillus속은 원래 균수보다 높게 복원되는 토양이 많았다. 토양 pH는 미생물수 복원율에 정의 영향을 주었다. 건토의 재습윤화에 의한 토양 미생물체량 복원율은 평균 65.3%였으며, 재습윤토의 미생물체 복원량과 형광성 Pseudomonas속간에 유의한 정의 상관관계가 있었다.

• 한국농공학회논문집
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• 제57권3호
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• pp.1-7
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• 2015

The objective of this study was to compare fecal microbes survival in soil between compost surface application and soil incorporation. The survival experiment was conducted in six styrofoam beds ($510{\times}325{\times}305(mm)$ in size) filled with sandy loam soil. A half of six boxes were received by compost surface application, while the other half were treated with compost-soil mixture. Duplicated surface and surbsurface soil (20 cm depth) samples were collected at various interval up to 50 days and analyzed for the determination of fecal coliforms and E. coli numbers. As expected, surface applied beds demonstrated two to three magnitudes order greater in both the study microorganisms as compared to soil incorporated beds. Microbial inactivation rate of soil surface was twice as great as subsurface soil condition probably due to exposure to sun light and environmental conditions including moisture loss. When rainfall occurred, microbes on the surface were transported into soil along with water movement. It was concluded that surface compost application may be easier to apply but pose higher risk of human exposure to microbes. Winter compost application may be favorable in alleviating health risk by giving some time for inactivation compared to spring application.