• 한국지반환경공학회 논문집
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• 제13권4호
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• pp.5-11
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• 2012

폐광산의 산성배수(AMD)는 황철석을 비롯한 다른 금속 황화물의 산화를 통해 발생한 폐광산의 산성배수는 환경오염의 원인 중 하나이다. 본 연구에서는 이러한 폐광산의 산성배수가 생성되는 과정에서 산화미생물의 관여 정도를 알아보고, 이를 억제할 수 있는 방법에 대해여 살펴보았다. 산성배수 발생에 영향을 미치는 산화미생물로 Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans을 선정하였으며, 이 산화미생물의 활성 및 생장 속도를 측정하였으며, 이산화염소$(ClO_2)$, NaCl, 그리고 계면활성제(ASOR-770) 를 산발생 억제제로 이용하여 실험을 진행하였다. 실험 결과 10ppm 이산화염소가 가장 효과적인 억제제였으며, 산화미생물의 활성도와 생장도를 20% 까지 감소시켜주었다.

• Food Science and Biotechnology
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• 제18권5호
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• pp.1243-1252
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• 2009

User-friendly software was developed to determine the shelf-life of perishable Korean seasoned side dishes in real time based on growth models of spoilage and pathogenic microorganisms. In the program algorithm, the primary spoilage and fastest-growing pathogenic organisms are selected according to the product characteristics, and their growth is simulated based on the previously monitored or recorded temperature history. To predict the growth of spoilage organisms with confidence limits, kinetic models for aerobic bacteria or molds/yeasts from published works are used. Growth models of pathogenic bacteria were obtained from the literature or derived with regression of their growth rate data estimated from established software packages. These models are also used to check whether the risk of pathogenic bacterial growth exceeds that of food spoilage organisms. Many example simulations showed that the shelf-lives of the examined foods are predominantly limited by the growth of spoilage organism rather than by pathogenic bacterial growth.

• Environmental Engineering Research
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• 제20권4호
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• pp.347-355
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• 2015

The growth kinetics of phototrophic microorganisms can be controlled by the light irradiance, the concentration of an inorganic nutrient, or both. A multi-component kinetic model is proposed and tested in novel batch experiments that allow the kinetic parameters for each factor to be estimated independently. For the cyanobacterium Synechocystis sp. PCC6803, the estimated parameters are maximum specific growth rate $({\mu}_{max})=2.8/d$, half-maximum-rate light irradiance $(K_L)=11W/m^2$, half-inhibition-rate light irradiance $(K_{L,I})=39W/m^2$, and half-maximum-rate concentration for inorganic carbon $(K_{S,Ci})=0.5mgC/L$, half-maximum-rate concentration for inorganic nitrogen $(K_{S,Ni})=1.4mgN/L$, and half-maximum-rate concentration for inorganic phosphorus $(K_{S,Pi})=0.06mgP/L$. Compared to other phototrophs having ${\mu}max$ estimates, PCC6803 is a fast-growing r-strategist relying on reaction rate. Its half-maximum-rate and half-inhibition rate values identify the ranges of light irradiance and nutrient concentrations that PCC6803 needs to achieve a high specific growth rate to be a sustainable bioenergy source. To gain the advantages of its high maximum specific growth rate, PCC6803 needs to have moderate light illumination ($7-62W/m^2$ for ${\mu}_{syn}{\geq}1/d$) and relatively high nutrient concentrations: $N_i{\geq}2.3 mgN/L$, $P_i{\geq}0.1mgP/L$, and $C_i{\geq}1.0mgC/L$.

• Journal of Microbiology and Biotechnology
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• 제15권2호
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• pp.337-345
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• 2005

The degradation of phenanthrene, a model PAH compound, by microorganisms either in the mixed culture or individual strain, isolated from oil-contaminated soil in oil refmery vicinity sites, was examined. The effects of pH, temperature, initial concentration of phenanthrene, and the addition of carbon sources on biodegradation potential were also investigated. Results showed that soil samples collected from four oil refinery sites in Korea had different degrees of PAH contamination and different indigenous phenanthrene-degrading microorganisms. The optimal conditions for phenanthrene biodegradation were determined to be 30$^{circ}C$ and pH 7.0. A significantly positive relationship was observed between the microbial growth and the rate of phenanthrene degradation. However, the phenanthrene biodegradation capability of the mixed culture was not related to the degree of PAH contamination in soil. In low phenanthrene concentration, the growth and biodegradation rates of the mixed cultures did not increase over those of the individual strain, especially IC10. High concentration of phenanthrene inhibited the growth of microbial strains and biodegradation of phenanthrene, but was less inhibitory on the mixed culture. Finally, when non-ionic surfactants such as Brij 30 and Brij 35 were present at the level above critical micelle concentrations (CMCs), phenanthrene degradation was completely inhibited and delayed by the addition of Triton X100 and Triton N101.

• International Journal of Industrial Entomology and Biomaterials
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• 제36권1호
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• pp.1-9
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• 2018

The purpose of this study was to determine the best method for minimizing the occurrence of Metarhizium anisopliae infection of Protaetia brevitarsis seluensis during mass breeding on agricultural farms. There is a high demand for the use of P. b. seluensis larvae in animal feed and as food for humans. However, mass breeding results in the entomopathogenic fungal (usually M. anisopliae) infection of P. b. seluensis. A mixture of microorganisms (Bacillus subtilis, Lactobacillus plantarum, and Saccharomyces cerevisiae) delayed fungal infection by M. anisopliae, which infected fewer P. b. seluensis when the microorganism mixture was added to sawdust as feed for P. b. seluensis. When sawdust with the effective microorganisms (EM) was given to P. b. seluensis for 30 d, their mortality rate was approximately 35 % less than that of the control group, which was fed sawdust without the EM. In addition, the growth of M. anisopliae on agar media spread with each bacterium as inhibited by up to 80 % more than those spread with 4 % sodium hypochlorite, which is a harmless fungal inhibitor generally used in agricultural farms for disinfection.

• 한국축산식품학회지
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• 제30권1호
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• pp.49-54
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• 2010

The aim of this research was to estimate the effect of temperature and develop predictive models for the growth of total viable cells (TVC) and Escherichia coli (EC) on chicken breast under aerobic and various temperature conditions. The primary models were determined by Baranyi model. The secondary models for the specific growth rate (SGR) and lag time (LT), as a function of storage temperature, were developed by the polynomial model. The initial contamination level of chicken breasts was around 4.3 Log CFU/g of TVC and 1.0 Log CFU/g of E. coli. During 216 h of storage, SGR of TVC showed 0.05, 0.15, and 0.54 Log CFU/g/h at 5, 15, and $25^{\circ}C$. Also, the growth tendency of EC was similar to those of TVC. As storage temperature increased, the values of SGR of microorganisms increased dramatically and the values of LT decreased inversely. The predicted growth models with experimental data were evaluated by $B_f$, $A_f$, RMSE, and $R^2$. These values indicated that these developed models were reliable to express the growth of TVC and EC on chicken breasts. The temperature changes of distribution and showcase in markets might affect the growth of microorganisms and spoilage of chicken breast mainly.

• 한국식품영양과학회지
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• 제30권5호
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• pp.806-813
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• 2001

천일염, 한주 소금, 구운 소금 및 죽염이 김치 발효에 중요한 영향을 미치는 미생물인 Leuconostoc mesenteroides, Lactobacillus plantarum과 산막효모인 Pichia membranaefaciens 및 식품오염의 지표균인 E. coli의 생육에 미치는 영향을 조사하였다. 각각의 소금을 3%, 5% 농도로 첨가하여 김치 발효 조건에 따라 배양 온도를 각각 1$0^{\circ}C$, 18$^{\circ}C$, 37$^{\circ}C$로 나누어 비교하였다. 그 결과 Leuconostoc mesenteroides는 배양 온도가 낮을수록, 소금 농도가 높을수록 성장이 저해되었으나 소금 종류별로는 특이할 만한 저해 효과는 나타나지 않았다. Lactobacillus plantarum도 마찬가지로 배양 온도가 낮을수록, 소금 농도가 높을수록 성장이 억제되었으며, 특히 18$^{\circ}C$, 5% 소금농도에서 죽염에 대해 저해 효과가 두드러졌고 1$0^{\circ}C$배양에서는 소금 종류와 농도에 관계없이 생육이 상당히 저조했다. Pichia membranaefaciens는 배양 온도에 관계없이 죽염에서 상당한 저해효과를 보였으며, 특히 18$^{\circ}C$, 5$^{\circ}C$ 소금농도에서는 전혀 자라지 못해 완전한 억제 효과를 보였다. E. coli도 다른 소금에 비해 1$0^{\circ}C$와 18$^{\circ}C$에서 죽염에 대해 저해 효과가 두드러졌다. 따라서 본 실험 결과 김치발효에도 어느 정도 관여하나 과다한 산 생성으로 김치의 가식기간을 단축시키는 Lactobacillus plantarum과 김치 표면에 산막을 형성하여 부패를 촉진시키는 Pichia membranaefaciens 그리고 식품오염의 지표균인 E. coli의 성장에 죽염이 다른 소금에 비해 상당한 저해 효과를 나타내었다.

• Journal of Animal Science and Technology
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• 제65권4호
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• pp.856-864
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• 2023

There are a variety of microorganisms in the animal intestine, and it has been known that they play important roles in the host such as suppression of potentially pathogenic microorganisms, modulation of the gut immunity. In addition, the gut microbiota and the livestock growth performance have long been known to be related. Therefore, we evaluated the interrelation between the growth performance and the gut microbiome of the pigs from 3 different farms, with pigs of varied ages ready to be supplied to the market. When pigs reached average market weight of 118 kg, the average age of pigs in three different farms were < 180 days, about 190 days, and > 200 days, respectively. Fecal samples were collected from pigs of age of 70 days, 100 days, 130 days, and 160 days. The output data of the 16S rRNA gene sequencing by the Illumina Miseq platform was filtered and analyzed using Quantitative Insights into Microbial Ecology (QIIME)2, and the statistical analysis was performed using Statistical Analysis of Metagenomic Profiles (STAMP). The results of this study showed that the gut microbial communities shifted as pigs aged along with significant difference in the relative abundance of different phyla and genera in different age groups of pigs from each farm. Even though, there was no statistical differences among groups in terms of Chao1, the number of observed operational taxonomic units (OTUs), and the Shannon index, our results showed higher abundances of Bifidobacterium, Clostridium and Lactobacillus in the feces of pigs with rapid growth rate. These results will help us to elucidate important gut microbiota that can affect the growth performance of pigs.

• 환경생물
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• 제23권2호
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• pp.135-140
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• 2005

In order to construct an artificial cultivation of Nostoc flagelliforme on solid medium, we attempted to assess the viability of approaches, which utilized either BG-11 agar or sand medium using both sterile and non-sterile algal segments. In the trial in which the BG -11 agar medium was inoculated with the non-sterile algal segments, the algae exhibited the rapid growth in the initial 4 days of cultivation. However, after 4 days of cultivation, the growth rate of the algae slowed, and the algal growth was completely stopped by 7 days of cultivation. When the BG -11 medium was inoculated with the sterile algal segments, the algae exhibited the rapid growth for a longer period of 8 days, reaching a length of 24.9 mm. The growth rate during this period was measured to be $24.5\%$. After the 8 days of cultivation, the algal growth rate began to slow and had almost stopped by the 13 days of cultivation. On the other hand, when the sterile algal segments were inoculated onto a sand plate, the algal segments decomposed, reaching total decomposition after 11 days of cultivation. By way of contrast, the desiccation treatment samples continued to grow for 14 days of cultivation. After 14 days of cultivation, the algae achieved a length of 26.1 mm, with a growth rate of $30.6\%$. Our results indicate that periodic desiccation may constitute an effective strategy for the prevention of algal decomposition.

• 환경위생공학
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• 제12권2호
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• pp.75-81
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• 1997

The study was investigated with denitrification of wastewater containing nitrate using upflow anaerobic sludge blanket process. Contents of this study were the determination of nitrate removal efficiency by various hydrogen donor addition, relationship between HRT, nitrate loading rate and growth constant of microorganism in case or various hydrogen donor addition etc. Results from this study were summurized as follows. In case of adding methanol, ethanol, sodium acetate as hydrogen donor, treatability of wastewater contained 200mg/l as nitrate was about 91%. But in addition of ethanol, sodium acetate in wastewater contained 40mg/l as nitrate, nitrate removal efficiency was 80%. While the treatment of nitrate showed the yield coefficient of microorganisms(Y) as 234.8, 234.35, and 247.68 g/VSS/g nitrate, respectively, showed specific growth rate(K) as 0.885, 0.934 and 0.917 respectively.