• Journal of Korean Society of Forest Science
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• v.90 no.4
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• pp.495-504
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• 2001

The objectives of this study were to understand the characteristics of Cd and Pb accumulation in various tissues of poplar species and the effects of ectomycorrhizal inoculation on the accumulation of above two heavy metals in the tissues. The mycelial inoculum of ectomycorrizal fungus, Pisolithus tinctorius was produced in peatmoss and vermiculite mixtures, and inoculated into potted soil with fresh cuttings of four species of Populus, P. alba ${\times}$ glandulosa (Pag). P. koreana ${\times}$ nigra var. italica (Pkn), P. nigra ${\times}$ maximowiczii(Pnm), and P. euramericana(Pe). The potted soils were added with 0, 30, and 80 ppm Cd, and 0, 50, and 300 ppm Pb. The cuttings were grown outdoors for about five months until the plants were harvested for measurement of growth, mycorrhizal infection, and metal contents in leaves, stems, and roots. The total dry weight of Pe treated with Cd and Pb was increased by mycorrhizal inoculation, while that of three other species was not affected by the inoculation. Cd was accumulated in the highest concentration in Pag and its concentration was increased by four times by mycorrhizal inoculation. The Pag accumulated Cd in the highest concentration in the leaves, while three other species accumulated Cd most in the roots. Pb was accumulated in the highest concentration in the roots of all the four species, while Pkn accumulated Pb in the leaves as much as in the roots. Without mycorrhizal inoculation Pe accumulated Pb most among the four species, while Pkn with mycorrhizal inoculation accumulated Pb two times more than in the same species without mycorrhizal inoculation. It was concluded that Pag was the most effective species among the four poplar species in Cd absorption from contaminated soil, and that Pe instead effectively absorbed Pb. Mycorrhizal inoculation increased the Cd accumulation in the tissues by four times in Pag and also increased Pb accumulation by two times in Pkn, with leaves being the major sites of metal accumulation. It may be possible to use these two poplar species in remedying the metal in the soil through the raking and removing the litter out of the contaminate site.

• Journal of Food Hygiene and Safety
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• v.32 no.6
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• pp.507-512
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• 2017

There has been increasing concern regarding misuse of disinfectants and sanitizers such as ethanol, sodium hypochlorite, and hydrogen peroxide for food contact surfaces in the food industry. Examining the efficacy of the concentration of currently used disinfectants and sanitizers is urgently required in the Korean society. This study aimed to develop predictive reduction models for Escherichia coli and Staphylococcus aureus in suspension, as a function of $ClO_2$ (chlorine dioxide) and contact time using response surface methodology. E. coli ATCC 10536 and S. aureus ATCC 6538 (initial inoculum, 8-9 log CFU/mL) in tryptic soy broth were treated with different concentrations of $ClO_2$ (5, 20, and 35 ppm) for different contact times (1, 3, and 5 min) following a central composite design. The polynomial reduction models for $ClO_2$ on E. coli and S. aureus were developed under the clean condition. E. coli reduction by 35 ppm $ClO_2$ for 1, 3, and 5 min was 2.49, 2.70, and 3.65 log CFU/mL, respectively. Also, S. aureus reduction by 35 ppm $ClO_2$ for 1, 3, and 5 min was 4.59, 5.25, and 5.81 log CFU/mL, respectively. The predictive response polynomial models developed were $R=0.43231-0.056492^*X_1-0.097771^*X_2+9.24167E-003^*X_1^*X_2+3.06333E-003^*X_1{^2}$ ($R^2=0.98$) on E. coli and $R=1.10542-0.20896^*X_1-0.046062^*X_2+8.30000E-003^*X_1^*X_2+8.73300E-003^*X_1{^2}$ ($R^2=0.99$) on S. aureus, where R was the bacterial reduction (log CFU/mL), $X_1$ was the concentration and $X_2$ was the contact time. Our predictive reduction models should be validated in developing the optimal concentration and contact time of $ClO_2$ for inhibiting E. coli and S. aureus on food contact surfaces.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.2
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• pp.208-213
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• 2007

The objective of the experiment was to determine the optimum cultural [moisture levels (55, 60 and 70%), days of fermentation (7, 14 and 21), temperature (25 and $35^{\circ}C$) of incubation)] and nutritional parameters (urea addition (0 and 2%) and variable levels of single super phosphate (0.25 and 0.50% SSP)) for bio-processing of the mustard (Brassica campestris) straw (MS) under solid-state fermentation (SSF) system. The performance of SSF was assessed in terms of favorable changes in cell wall constituents, protein content and in vitro DM digestibility of the MS. Sorghum based inoculum (seed culture) of Ganoderma lucidum to treat the MS was prepared. The 50 g DM of MS taken in autoclavable polypropylene bags was mixed with a pre-calculated amount of water and the particular nutrient in the straw to attained the desired levels of water and nutrient concentration in the substrate. A significant progressive increase in biodegradation of DM (p<0.001), NDF (p<0.01) and ADF (p<0.05) was observed with increasing levels of moisture. Among the cell wall constituents the loss of ADF fraction was greatest compared to that of NDF. The loss of DM increased progressively as the fermentation proceeded and maximum DM losses occurred at 28 days after incubation. The protein content of the treated MS samples increased linearly up to the day $21^{th}$ of the incubation and thereafter declined at day $28^{th}$, whereas the improvement in in vitro DM digestibility were apparent only up to the day $14^{th}$ of the incubation under SSF and there after it declined. The acid detergent lignin (ADL) degradation was slower during the first 7 days of SSF and thereafter increased progressively and maximum ADL losses were observed at the day $28^{th}$ of the SSF. The biodegradation of DM and ADL was not affected by the variation in incubation temperature. Addition of urea was found to have inhibitory effect on fungal growth. The effect of both the levels (0.25 and 0.50) of SSP addition in the substrate, on DM, NDF, ADF, cellulose and ADL biodegradation was similar. Similarly, the protein content and the in vitro DM digestibility remain unaffected affected due to variable levels of the SSP inclusion in the substrate. From the results it may be concluded that the incubation of MS with 60 percent moisture for 21 days at $35^{\circ}C$ with 0.25 percent SSP was most suitable for MS treatment with Ganoderma lucidum. Maximum delignification, enrichment in the protein content and improvement in in vitro DM digestibility were achieved by adopting this protocol of bioprocessing of MS.

• Korean journal of applied entomology
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• v.16 no.1 s.30
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• pp.1-6
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• 1977

The 'Kresek' disease in Korea caused by Xanthomonas oryzae was first found from eight counties in Jeon-nam and Kyungnam province in 1976. The study has been carried mainly on the grouping of pathogens and reproduction of the symptoms on Milyang #23, the variety had shown severe damages at the fields, by using the isolates from Hwa-sun and Kwang-san counties where the first epidemics took place. 1. The 'Kresek' disease was found mainly on Milyang #23, a new variety, at Hwa-sun, Mu-an, Kang-jin. Yung-am, Gog-sung counties in Jeon-nam province and Jin-yang county in Kyung-nam province. 2. The groups of 'Kresek' causing pathogens were the same of those producing bacterial leaf blight symptoms such as group I , II, IN and V of Xanthomonas oryzae. 3. Seventeen out of 21 isolates from Hwa-sun county where the first and severe damage found belonged to group IV, 2 to group II and 2 to group V All of 5 isolates from Kwang-san county belonged to the group IN. 4. The 'Kresek' type symptom could reproduced within 5 days after inoculation to seedlings by using root tut, spray and needle inoculation methods. j. The most of effective method for the inoculation was root cut, and then were spray and needle method. respectively. The higher concentration of inoculum produced the higher disease incidence.

• Korean Journal of Environmental Agriculture
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• v.13 no.3
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• pp.386-395
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• 1994

As a basic research on applying the microbial strains which had been isolated and proved to remove heavy metals, such as Pb, Cd, Zn, and Cu in This laboratory to actual wastewater treatment, optimum condition of the treatment system with addition of single or multiple species of pollutants and microorganisms were investigated at small scale. Concentration of the bacterial inoculum was 3000mg/L and 1500mg/L of MLSS for treatment with single and multiple species, respectively. Removal rates of heavy metals were expressed at HRT’s (Hydraulic Retention Time) of 12, 24, and 48 hr. Removal rates of Pb, Cd, Zn, and Cu after 12 days at HRT of 24hr with addition of single and multiple species were 93%, 90%, 80%, and 39%, and 75%, 90%, 74%, and 48%, respectively. Judging from these results, treatment capability of the isolated strains is excellent. Hence, the microorganisms are expected to be applicable to actual wastewater treatment.

• Journal of Bio-Environment Control
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• v.29 no.1
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• pp.96-102
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• 2020

Fusarium wilt caused by Fusarium oxysporum is a devastating disease limiting production of watermelon in Korea. The best way to control diseases is to use resistant gourd rootstock on watermelon. This study was conducted to establish an efficient screening method for resistant bottle gourd to Fusarium oxysporum f. sp. lagenaria. To develop an efficient inoculation method, incubation temperature after inoculation (15, 20, 25, and 30℃), inoculum concentration (1 × 10⁵, 5 × 10⁵, 1 × 10⁶, and 5 × 10⁶ conidia·mL^-1), and growth stages of seedlings (7, 10, 13, and 16 days) was investigated. Disease development of Fusarium wilt of bottle gourd was little affected by differences in incubation temperature and growth stages of seedlings. But resistant lines were more susceptible and appeared more severe symptoms at the higher inoculation level. Taken together, we suggest that an effective screening method for resistant gourd plant to Fusarium wilt is to dip the roots of 10-day old seedlings in spore suspension of 1 × 10⁵ - 1 × 10⁶ conidia·mL^-1, for 30 min, to transplant the seedlings into a non-infected soil, and then to incubate the inoculated plants in a growth room at 25℃ for 3 weeks to develop Fusarium wilt.

• Research in Plant Disease
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• v.20 no.4
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• pp.245-252
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• 2014

The study was performed to establish an efficient screening method for resistant cucumber to Fusarium oxysporum f. sp. cucumerinum. The isolate KR5 was identified as F. oxysporum f. sp. cucumerinum based on molecular analyses of ITS and TEF genes and host-specificity test on cucurbits including melon, oriental melon, cucumber, and watermelon. Then four cucumber and two rootstock cultivars showing different resistance degrees to the Fusarium wilt pathogen KR5 were selected. And development of Fusarium wilt of the six cultivars according to several conditions, including incubation temperature after inoculation, inoculum concentration, root wounding, and growth stages of seedlings, was investigated. Disease severity of Fusarium wilt on the resistant cultivars was changed with incubation temperatures after inoculation. The resistant cultivars showed the higher resistance when inoculated plants were kept at 25 or $30^{\circ}C$ than at $20^{\circ}C$. Among four different growth stages of the seedlings, seven-day-old seedling represented the most difference of resistance and susceptibility to Fusarium wilt. From above results, we suggest that an efficient screening method for resistant cucumber to F. oxysporum f. sp. cucumerinum is to dip the non-cut roots of seven-day-old seedlings in spore suspension of $1.0{\times}10^6-1.0{\times}10^7$ conidia/ml and to transplant the seedling into a non-infected soil, and then to incubate the inoculated plants in a growth room at $25^{\circ}C$ for 3 weeks to develop Fusarium wilt.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.630-638
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• 2019

Nitrous oxide (N₂O) is a greenhouse gas with a global warming potential 310 times higher than that of carbon dioxide. In this study, an N₂O-reducing consortium was obtained by enrichment culture using advanced treatment sludge as the inoculum. The dominant bacteria in the consortium were Sulfurovum (17.95%), Geobacter (14.63%), Rectinema (11.45%), and Chlorobium (8.24%). The consortium displayed optimal N₂O reducing activity when acetate was supplied as the carbon source at a carbon/nitrogen ratio (mol·mol^-1) of 6.3. The N₂O reduction rate increased with increasing N₂O concentration at less than 3,000 ppm. Kinetic analysis revealed that the maximum N₂O reduction rate of the consortium was 163.9 ㎍-N·g-VSS^-1·h^-1. Genes present in the consortium included nosZ (reduction of nitrous oxide to N₂), narG (reduction of nitrate to nitrite), nirK (reduction of nitrite to nitric oxide), and norB (reduction of nitric oxide to nitrous oxide). These results indicate that the N₂O-reducing consortium is a promising bioresource that can be used in denitrification and N₂O mitigation.

• Microbiology and Biotechnology Letters
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• v.17 no.1
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• pp.8-13
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• 1989

The optimum conditions for ethanol fermentation and ethanol productivity of the fusant ESC-14-15 were examined in a mini-jar formentor scale (working volume : 2.5 liters) to assess the possibility of practical application. Addition of yeast extract to fermentation broth greatly enhanced the ethanol productivity and shortened the period of fermentation. The pH 4.2 was more favorable than pH 5.5 with respect to ethanol productivity and fermentation speed. The optimum concentration of liquefied potato starch for ethanol fermentation of FSC-14-15 was 15%(w/v) and the corresponding productivity was 8.7%(v/v) of ethanol with an efficiency of 80.6% to the theoretical maximum. When the fresh fermentation broth containing 20% of liquefied potato starch was inoculated with love(v/v) of inoculum, the fusant FSC-14-75 produced 11.0%(v/v) of ethanol in 4 days, which is considered comparable to that from an industrial process. From the liquefied cassava starch or the equal mixture of liquefied barley and sweet potato starch prepared according to the same method as in the industrial process except saccharification step, the fusnnt FSC-14-75 produced 8.5%(v/v) or 7.6%(v/v) of ethanol in 4 days, respectively.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.2
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• pp.28-35
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• 2015

In this study, the experiment was carried out to produce methane by applying Semi-Continuous Leachate Recirculation Anaerobic Digestion System fed with source separated food waste from school cafeteria. There were two systems and each system consisted of a bioreactor and a liquid tank. Each bioreactor had a screen near the bottom of the reactor. 2.5L of separated liquid was transferred to the liquid tank for 30min each day by using a tubing pump and the liquid from the liquid tank was pumped to the bioreactor at the upper of the bioreactor as soon as the transfer was ended. Through this circulation, the liquid having high concentration of VFAs was supplied to the top of bioreactor. At the beginning of the experiment, food waste/inoculum anaerobic sludge volume ratio was 2:8 that is 9g VS/L of OLR(Organic Loading Rate). Feeding was conducted every two weeks. Experimental results showed that the contents of moisture, combustible matter, ash were 65.91%, 32.73%, and 1.36%, respectively. Two different food waste loading were studied. The average organic loading rates were 3.51g VS/d for System A and 3.86g VS/d for System B, respectively. The average produced methane based on food waste fed to bioreactor were observed as $6.30m^3CH_4/kgVS{\cdot}d$ for system A and $4.94m^3CH_4/kgVS{\cdot}d$ for System B, respectively.