• Journal of Soil and Groundwater Environment
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• v.19 no.2
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• pp.16-24
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• 2014

To test the potential effects of extracellular electron shuttles (EES) on the rate and extent of heavy metal release from contaminated soils during microbial iron reduction, we created anaerobic batch systems with anthraquinone-2,6-disulfonate (AQDS) as a surrogate of EES, and with contaminated soils as mixed iron (hydr)oxides and microbial sources. Two types of soils were tested: Zn-contaminated soil A and As/Pb-contaminated soil B. In soil A, the rate of iron reduction was fastest in the presence of AQDS and > 3500 mg/L of total Fe(II) was produced within 2 d. This suggests that indigenous microorganisms can utilize AQDS as EES to stimulate iron reduction. In the incubations with soil B, the rate and extent of iron reduction did not increase in the presence of AQDS likely because of the low pH (< 5.5). In addition, less than 2000 mg/L of total Fe(II) was produced in soil B within 52 d suggesting that iron reduction by subsurface microorganisms in soil B was not as effective as that in soil A. Relatively high amount of As (~500 mg/L) was released to the aqueous phase during microbial iron reduction in soil B. The release of As might be due to the reduction of As-associated iron (hydr)oxides and/or direct enzymatic reduction of As(V) to As(III) by As-reducing microorganisms. However, given that Pb in liquid phase was < 0.3 mg/L for the entire experiment, the microbial reduction As(V) to As(III) by As-reducing microorganisms has most likely occurred in this system. This study suggests that heavy metal release from contaminated soils can be strongly controlled by subsurface microorganisms, soil pH, presence of EES, and/or nature of heavy metals.

• Journal of Food Hygiene and Safety
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• v.9 no.3
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• pp.151-161
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• 1994

Gamma irradiation was applied to red ginseng for improving its quality. Irradiation at 5~7 kGy was effective for sterilizing all contaminated microorganisms of red ginseng. At the dose levels, no significant shanges in physicochemical properties (color, saponin, lipid rancidity and fatty acids etc.) were observed even after 6 months storage. Gamma irradiation was also effective for the improving hygienic quality of packed red ginseng with high moisture content (up to 20%), without any quality deterioration.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.4
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• pp.75-85
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• 2005

A study was performed to examine the effects of reclaimed-water irrigation on microorganism con-centration in ponded-water of paddy rice plots. Several treatments were used and each one was triplicated to evaluate the change of indicator microorganisms (total coliforms (TC), fecal coliforms FC), and E. coli) concentrations in 2003 and 2004 growing seasons. Their concentrations increased significantly right after irrigation, but decreased about $45\%$ in 24 hours. It implies that agricultural activities such as plowing and fertilizing should be practiced one or two days after irrigation considering health-risks. Treatments with UV-disinfected water irrigation demonstrated significantly lower concentrations than others including control plots where natural surface water was irrigated. The monitoring results from actual paddy rice fields and experimental paddy plots showed that concentrations of indicator microorganisms ranged from $10^2\;to\;10^5$ MPN/100mL. A comprehensive assessment of existing agricultural practices and a thorough monitoring in the field as well as treatment-plots are recommended to make more realistic national guidelines more applicable. UV-disinfected water irrigation reduced microorganism concentrations in paddy fields down to below the concentration of conventional paddy rice culture, and is thought to be an effective and feasible measure fur agricultural reuse of secondary effluent.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.127-130
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• 2005

The feasibility of stimulating in situ aerobic cometabolic activity of indigenous microorganisms was investigated in a trichloroethene(TCE)-contaminated aquifer, A series of single-well natural drift tests (SWNDT) was conducted by injecting site groundwater amended with a bromide tracer and combinations of toluene, oxygen, nitrate, ethylene and TCE into an existing monitoring well and by sampling the same well over time. Transformation of ethylene, a surrogate of overall TCE transformation activity, was also observed, and its transformation results in the production of ethylene oxide, suggesting that some tolune-oxidizing microorganisms stimulated may express a monooxygenase enzymes. Also in situ transformation of TCE was confirmed by dilution-adjusted data analysis developed in this study. These results indicate that, in this environment, toluene and oxygen additions stimulated the growth and aerobic cometabolic activity of indigenous microorganisms expressing monooxygenase enzymes and that these are responsible for observed toluene utilization and cometabolism of ethylene and TCE. The simple, low-cost field test method provides an effective method for conducting rapid field assessments and pilot testing of aerobic cometabolism of TCE, which has previously hindered application of this technology to groundwater remediation.

• The Korean Journal of Food And Nutrition
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• v.31 no.2
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• pp.308-312
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• 2018

Even though chlorine dioxide ($ClO_2$) is utilized in a pre-treatment due to its effective sterilizing activity for microorganisms and its safety for food, it has a limitation in maintaining freshness of the food product. In this study, a low-concentration $ClO_2$ gas was produced in a packaging form of air-permeable gel pack so that it could be released continuously over several days. The amount of $ClO_2$ gas emission and microbial inactivation effect against foodborne pathogens were measured during the release of $ClO_2$ gas. As a result of measuring the change of color in order to confirm whether the chlorine dioxide gas was eluted in the form of a sustained release, the yellowness was significantly higher at higher gel pack concentration and higher value during storage periods. The slow-released $ClO_2$ gel-pack showed clear inactivation effect against Escherichia coli and Staphylococcus aureus with 99.9% inactivation efficiency. As a result of measuring the sterilization effect of Listeria monocytogenes by the concentration of chlorine dioxide gas, the sterilization effect was increased as the concentration was increased. Therefore, the slow-released $ClO_2$ gel-pack is feasible to apply for industry usages.

• Korean journal of food and cookery science
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• v.24 no.1
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• pp.99-105
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• 2008

Laver-wrapped rice and laver-wrapped rice containing a vinegar blend (vinegar:sugar:water:salt = 5:2:2:1) were prepared and their degrees of aging from 10 to $30^{\circ}C$, total cell numbers, and total coliforms were examined and compared. The total cell numbers of the laver-wrapped rice increased to 1 log cfu/g at 36 hours, and the total cell numbers of the laver-wrapped rice with vinegar had increased to within 48 hours. At $20^{\circ}C$ for 24 hrs, the total cell numbers for the laver-wrapped rice had increased to 5 log cfu/g: whereas trhe total cell numbers of the laver-wrapped rice with vinegar(5ml of vinegar marinade mixed into 100g of steamed rice), stored at the same conditions had not increased. In the vinegar-marinated rice (2ml/100g rice), microorganisms appeared at 18 hours. However, at the concentration of 5ml/l00g of rice, microorganisms were not observed at 24 hours. Coliforms did not appear in the laver-wrapped rice nor in the laver-wrapped rice with vinegar(prepared at 10ml/100g) until 48 hours. When stored at 10 and $20^{\circ}C$, no microorganisms were found in the laver-wrapped rice with vinegar until 48 hours, respectively. However, at $30^{\circ}C$, microorganisms were observed in the laver-wrapped rice from 24 hours, and from 48 hours in the laver-wrapped rice with vinegar. These results suggest that laver-wrapped rice should be consumed within one day. The number of microorganisms inside the laver-wrapped rice reached 6 log cfu/g by 24 hours, but the increase in the laver-wrapped rice with vinegar was slower. The aging(% damaged starch) of the laver-wrapped rice with vinegar(5ml/100g the rice) stored at $20^{\circ}C$ was reduced, with 3% damaged starch at 24 hours. Consumer evaluations revealed that the laver-wrapped rice prepared with 5ml of the vinegar blend received higher scores for flavor, taste, texture, and overall acceptance as compared to the control. In particular, significantly higher scores were given for taste, texture, and overall acceptability. In summary, the laver-wrapped rice with vinegar had an extended shelf-life(more than 1 day) at storage temperatures of $20-30^{\circ}C$, as well as reduced retrogradation. In addition, based on consumer evaluations, adding vinegar to laver-wrapped rice laver is effective for increasing overall acceptability.

• The Korean Journal of Food And Nutrition
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• v.9 no.1
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• pp.45-51
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• 1996

Korean traditional Sikhye is made from rice and malt, and It's main product Is maltose. However commercial Sikhye differs from traditional Sikhye because it's main component is sucrose. Sikhye industry faces many problems such as contamination of malt with microorganisms, low amylase activity of malt and technical difficulties. There is no commercial Sikhye which is only using rice and malt by these reasons. To produce the traditional Sikhye free from these problems, it is necessary to restrict the microorganisms of malt and to standardize the amylase activity of malt. In addition, the Introduction of effective control and sanitaric process is required. In Sikhye production. if $\beta$-amylase and isoamylase or pullulanase were added, starch could be saccharified 100% as maltose. Accordingly, this method brings us the low cost of Sikhye.

• Journal of Applied Biological Chemistry
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• v.56 no.3
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• pp.171-177
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• 2013

Efficient extraction of total proteins from soil microorganisms is tedious because of small quantity. In this regard, an improved method for extraction of whole cell proteins is developed from soil microorganisms, Saccharomyces cerevisiae and Pichia pastoris. of which the cell wall are very strong. Pretreatment with NH4OH prior to the final extraction using NaOH/SDS was tried under the basis that ammonium ion was possible to enhance the permeability and/or to weaken the yeast cell walls. The pre-treatment of yeast cells with NH4OH drastically enhanced the protein extraction when it was compared with control (without NH4OH pre-treatment). At the pre-treatment of 0.04 N NH4OH at pH 9.0, about 3 fold of proteins was obtained from p. pastoris. Ammonium hydroxide appears to penetrate into the yeast cell walls more readily at basic pH. The effect of NH4OH pretreatment was pH dependent. The methods developed in this experiment might be applicable for an effective extraction of yeast proteins for the purpose of biochemical studies, especially proteomic analysis.

• International Journal of Oral Biology
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• v.41 no.2
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• pp.75-81
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• 2016

Human mouth environment is known to include a variety bacteria, including Streptococcus spp., Staphylococcus spp., Actinomyces spp., Lactobacillus spp., Candida spp., Enterobacteriaceae, et al. Human oral microorganisms can cause dental caries, gingivitis, periodontitis, respiratory tract infection, and cardiovascular disease. Thus, right denture cleaning is essential to oral and general human health. The aim of this study was to evaluate the bactericidal effect of a sodium dichloroisocyanurate-based effervescent tablet (Aos Denti Germ, Aos Company, Chungbuk, Korea) against oral microorganisms. A total of 5 species Streptococcus spp. (Streptococcus anginosus, Streptococcus mitis, Streptococcus mutans, Streptococcus oralis, and Streptococcus sobrinus), Actinomyces oris, Candida albicans, and Escherichia coli were used in this study. All strains were exposed to the distilled water prepared with effervescent tablet. After the exposure, the mixture of strains and effervescent tablet was inoculated onto blood agar or MacConkey agar plate and cultured at $36^{\circ}C$. All strains were killed immediately on exposure to effervescent tablet. The results suggested that effervescent tablet could be used as an effective denture cleanser for dental hygiene.

• The Plant Pathology Journal
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• v.29 no.2
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• pp.174-181
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• 2013

The plant growth-promoting rhizobacterium Ochrobactrum lupini KUDC1013 elicited induced systemic resistance (ISR) in tobacco against soft rot disease caused by Pectobacterium carotovorum subsp. carotovorum. We investigated of its factors involved in ISR elicitation. To characterize the ISR determinants, KUDC1013 cell suspension, heat-treated cells, supernatant from a culture medium, crude bacterial lipopolysaccharide (LPS) and flagella were tested for their ISR activities. Both LPS and flagella from KUDC1013 were effective in ISR elicitation. Crude cell free supernatant elicited ISR and factors with the highest ISR activity were retained in the n-butanol fraction. Analysis of the ISR-active fraction revealed the metabolites, phenylacetic acid (PAA), 1-hexadecene and linoleic acid (LA), as elicitors of ISR. Treatment of tobacco with these compounds significantly decreased the soft rot disease symptoms. This is the first report on the ISR determinants by plant growth-promoting rhizobacteria (PGPR) KUDC1013 and identifying PAA, 1-hexadecene and LA as ISR-related compounds. This study shows that KUDC1013 has a great potential as biological control agent because of its multiple factors involved in induction of systemic resistance against phytopathogens.