• New & Renewable Energy
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• v.7 no.2
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• pp.10-17
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• 2011

Korea is the 11th largest energy consumption country and 96% of its total energy consumption depends on imports from overseas. Therefore it is a very important task to secure renewable energy sources which can reduce both the carbon-dioxide emission and dependency on overseas energy imports. Among the various renewable energy sources, organic wastes are important sources. In Korea, 113 million toe of methane is generated from organic wastes annually, but only 3.7% is effectively used for energy conversion. Thus, it is very important to make better use of organic wastes, especially for power generation. The goals of this project are to develope the fuel supplying system of Bio Gasturbine (GT) for 5MW-class co-generation system. The fuel supplying system mainly consists of $H_2S$ removal system, Bio Gas compression system, Siloxane removal system and moisture separating systems. The fuel requirement of 5MW-class GT is at around 60% of $CH_4$, $H_2S$ (<30 ppm), Siloxane(<10 mg/$nm^3$) and supply pressure (> 25 bar) from biogas compressor. Main mechnical charateristics of Bio Gasturbine system have the specific performance; 1) high speed turbine speed (12,840 rpm) 2) very clean emmission NOx (<50 ppm) 3) high efficiency of energy conversion rate. This paper focuses on the development of design technology for food waste biogas pretreatment system for 5MW-class biogas turbine. The study also has the plan to replace the fuel of gas turbine and other distributed power systems. As the increase of bioenergy, this system help to contribute to spread more New & Renewable Energy and the establishment of Renewable Portfolio Standards (RPS) for Korea.

• Toxicological Research
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• v.17
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• pp.139-144
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• 2001

Chewing betel quid is associated with an increased risk of oral cancer. The betel quid chewed in Taiwan includes the inflorescence of Piper betle, which contains high concentrations of safrole (15 mg/fresh weight). Piper betle leaf is also used in betel quid; however, the concentration of safrole in betel leaf has not been documented. Chewing betel quid may contribute to safrole exposure in man (420 mm in saliva). Using $a^{32}$P-postlabeling method, we have recently demonstrated the presence of stable safrole-like DNA adducts in human oral tissues following betel quid chewing. Safrole is a rodent hepatocar-cinogen, and the real nature of safrole-DNA adducts in human tissues beside oral has not been elucidated. In this paper, we tested the safrole DNA adducts forming potential in human hepatic and oral derived cells by the ${32}^P$-postlabeling technique. The results suggest that oral cancer derived cell OC-2 alone is not able to form safrole-DNA adduct. However, safrole DNA adducts can be detected following I'-hydroxysafrole, a proximate safrole metabolite, treatment. In addition, pretreament of cytochrome P450 inducers also enhanced the formation of previously undetectable safrole DNA adducts. This finding couples with our previous results suggest that oral may serve as a target tissue for safrole, and safrole may be involved in oral carcinogenesis.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1114-1119
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• 2004

The biofilms on pipe walls in water distribution systems are of interest since they can lead to chlorine demand, coliform growth, pipe corrosion, and water taste and odor problems. As such, the study described in this paper is part of an AWWARF and Tampa Bay Water tailored collaboration project to determine the effect of blending different source waters on the water quality in various distribution systems. The project was based on 18 independent pilot distribution systems (PDS), each being fed by a different water blend (7 finished waters blended in different proportions). The source waters compared were groundwater, surface water, and brackish water, which were treated in a variety of pilot distribution systems, including reverse osmosis (RO) (desalination), both membrane and chemical softening, and ozonation-biological activated carbon (BAC), resulting in a total of 7 different finished waters. The observations from this study consistently demonstrated that unlined ductile iron was more heavily colonized by a biomass than galvanized steel, lined ductile iron, and PVC (in that order) and that the fixed biomass accumulation was more influenced by the nature of the supporting material than by the water quality (including the secondary residual levels). However, although the bulk liquid water cultivable bacterial counts (i.e. heterotrophic plate counts or HPCs) did not increase with a greater biofilm accumulation, the results also suggested that high HPCs corresponded to a low disinfectant residual more than a high biofilm inventory. Furthermore, temperature was found to affect the biofilms, plus the AOC was important when the residual was between 0.6 and 2.0 mg $Cl_2/l$. An additional aspect of the current study was that the potential of the exoproteolytic activity (PEPA) technique was used along with a traditional so-called destructive technique in which the biofilm was scrapped off the coupon surface, resuspended, and cultivated on an R2A agar. Both techniques indicated similar trends and relative comparisons among the PDSs, yet the culturable biofilm values for the traditional method were several orders of magnitude lower than the PEPA values.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.2
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• pp.27-36
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• 2015

The objective of this paper was to quantitatively analyze the effect of concentrated animal feeding operations (CAFO) NPS pollution on a small watershed water quality. Monitoring was conducted from March to October, 2013. Monthly flow rate and selected water quality at each monitoring site were measured during dry days. Rainy day monitoring also was conducted. Modeling was conducted to evaluate the effect of CAFO NPS pollution on the water quality at the watershed outlet. The highest and mean concentration of selected water quality indices during rainy days were higher than those in dry days in general. The highest TN concentration measured at the CAFP pollution discharge point was 237.831 mg/L. The results revealed that the CAFO NPS pollution sources could be equally blamed for the water quality degradation of the stream. However, the effect of the NPS pollution from CAFOs seemed not to be very influential to the watershed water quality at the outlet. SWAT modeling revealed that the TN load was reduced by 18.95 %, 23.39 % and 30.53 % at the watershed outlet if the TN load at the CAFO NPS pollution discharge point reduced by 20 %, 40 % and 60 %, respectively. It was thought that the natural attenuation processes played an important role. The modeling was based only on the assumption of the load reduction and not verified by the monitored data. Therefore, it was suggested that a long term monitoring studies for the evaluation of the impact of CAFO NPS pollution on the watershed water quality be conducted.

• Journal of Microbiology and Biotechnology
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• v.25 no.9
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• pp.1476-1484
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• 2015

Three endoxylanase-encoding genes from the moderately themophilic chemoorganotrophic bacterium Melioribacter roseus were cloned and expressed in Escherichia coli. Genes xyl2091 (Mros_2091) and xyl2495 (Mros_2495) encode GH10 family hydrolases, whereas xyl2090 (Mros_2090) represents the GH30 family. In addition to catalytic domains, Xyl2090 and Xyl2091 contain carbohydrate-binding modules that could facilitate their binding to xylans and Por sorting domains associated with the sorting of proteins from the periplasm to the outer membrane, where they are covalently attached. Recombinant endoxylanase Xyl2495 exhibited a high specific activity of 1,920 U/mg on birchwood xylan at 40℃. It is active at low temperatures, exhibiting more than 30% of the maximal activity even at 0℃. Endoxylanases Xyl2090 and Xyl2091 have lower specific activities but higher temperature optima at 80℃ and 65℃, respectively. Analysis of xylan hydrolysis products revealed that Xyl2090 generates xylo-oligosaccharides longer than xylopentaose. Xylose and xylobiose are the major products of xylan hydrolysis by the recombinant Xyl2091 and Xyl2495. No activity against cellulose was observed for all enzymes. The presence of three xylanases ensures efficient xylan hydrolysis by M. roseus. The highly processive "free" endoxylanase Xyl2495 could hydrolyze xylan under moderate temperatures. Xylan hydrolysis at elevated temperatures could be accomplished by concerted action of two cell-bound xylanases; Xyl2090 that probably degrades xylans to long xylo-oligosaccharides, and Xyl2091 hydrolyzing them to xylose and xylobiose. The new endoxylanases could be useful for saccharification of lignocellulosic biomass in biofuels production, bleaching of paper pulp, and obtaining low molecular weight xylooligosaccharides.

• Journal of Microbiology and Biotechnology
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• v.23 no.8
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• pp.1084-1091
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• 2013

In this paper, two statistical methods were applied to optimize medium components to improve the production of the milk-clotting enzyme by Bacillus amyloliquefaciens D4. First, wheat bran juice, skim milk powder, and $Na_2HPO_4$ were shown to have significant effects on D4 enzyme production using the Plackett-Burman experimental design. Subsequently, an optimal medium was obtained using the Box-Behnken method, which consisted of 3.31 g/l of skim milk powder, 5.0 g/l of sucrose, 0.1 g/l of $FeSO_4{\cdot}7H_2O$, 0.1 g/l of $MgSO_4{\cdot}7H_2O$, 0.1 g/l of $MnSO_4{\cdot}2H_2O$, 0.1 g/l of $ZnSO_4{\cdot}7H_2O$, 1.52 g/l of $Na_2HPO_4$, and 172.45 g/l of wheat bran juice. With this optimal medium, the milk-clotting enzyme production was remarkably enhanced. The milk-clotting enzyme activity reached 3,326.7 SU/ml after incubation of 48 h, which was 1.76-fold higher than that of the basic medium, showing that the Plackett-Burman design and Box-Behnken response surface method are effective to optimize medium components, and B. amyloliquefaciens D4 possessed a high rennet-producing capacity in the optimal medium.

• Journal of Nutrition and Health
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• v.25 no.1
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• pp.3-11
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• 1992

This paper examines the effects of dietary fats on the fatty acid composition and market enzyme activites during liver damage in 2-acetylaminofluorene treated rats. Weaning Sprague-Dawley male rats were fed the diet of beef tallow(BT source of sturated fatty acid) corn oil(CO source of n-6 fatty acid) and perilla oil(PO source of n-3 fatty acid) at the level of 15% fat. Ten days after feeding 2-acetylaminofluorene(2-AAF) was injected intraperitoneally twice every week at the level of 50mg/kg body weight for 7 weeks. Liver microsomal and cytosolic fractions were collected to determine the microsomal fatty acid composition lipid peroxide(malondialdehyde MDA) contents glucose 6-phosphatase(G6 Pase) activity cytochrome(Cyt) P-450 contents and cytosolic glutathione S-transferase(G6 Pase) activity cytochrome(Cyt) P-450 contents and cytosolic glutathione S-transferase(GST) activity. The fatty acid composition in microsomal fraction was reflected by different dietary fats. By 2-AAF treatment linoleic acids were increased regardless of the diet MDA contents were higher in CO group than it was in BT group. However 2-AAF treatment decreased MDA contents in all dietary groups. G6Pase activity of BT group was higher than those of the other gropus. CO group had the highest Cyt P-450 contents and 2-AAF treatment lowered Cyt P-450 contents only in CO gropu GST activites were higher in CO than in BT group whereas the enzyme activites were increased by 20AAF treatment in all dietary groups. These results suggest that dietary fats and 2-AAF treatment in all dietary groups,. These results suggest that dietary fats and 2-AAF treatment affect microsomal fatty acid composition The enzyme activities concerned with liver damage were influenced differently by dietary fats and 2-AFF treatment Although PO diet contains much more polyunsaturated fatty acids than CO diet PO diet doesn't cause more oxidant stress compared with CO diet in these data.

• The Korean Journal of Mycology
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• v.2 no.1
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• pp.25-29
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• 1974

1. Penicillium sp. C 13-13 strain was obtained with the treatment of mutagenic agents(N.T.G.) and by single spore isolation method from the Penicillium sp. C8-14 strain, which was reported in the previous paper. 2. The above strain had a few spores and to obtain seed culture, it was cultured at $30^{\circ}C$ and initial pH $4.5{\sim}5.0$, with air rate 6l/min., and agitation 600 rpm for 48 hours in 10% wheat bran medium in 20l- Jar fermenter. When the broth that had above 70ml of mycelium was inoculated into wheat bran medium and incubated at $29{\sim}33^{\circ}C$ for 72 hrs, the cellulase activity of the koji was higher. 3. Adding calcium chloride and magnecium sulfate to the wheat bran medium to 1.5% and 0.015% respectively, the cellulase activity of the koji was higher than that of the control.

• Journal of Korean Society on Water Environment
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• v.33 no.2
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• pp.181-186
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• 2017

This paper aimed to evaluate the results of alternative acute toxicity test on 83 wastewater samples. Each sample was tested by traditional method (using laboratory cultured D. magna as a test organism) and alternative method (using Toxikit which can be purchased from a specialized company). The relationship between Lab. culture toxicity and Toxkits toxicity indicated good relation ($r^2=0.84$, p<0.01, n = 83). Number of samples which showed a small difference of lower than 0.5 between two test methods were 52 and they account for 63 percent of collected samples. In addition, these 52 samples had a lower average toxicity of TU 0.5 (Lab. culture method) and TU 0.45 (Toxkits method). Whereas samples which indicated big difference of test results between two methods, had a tendency to show higher toxicity. From these results, alternative toxicity test method could be applied to the official test method, if samples would have a lower toxicity less than TU 2. Also, Toxikit standard toxicant test results indicated $EC_{50}$ values between 0.93 and 1.68 mg/L and these results were considered as valid for quality control standard.

• The Korea Journal of Herbology
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• v.30 no.4
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• pp.29-35
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• 2015

Objectives : The objective of this research was to investigate the antibacterial and antioxidant activities of bio-fermented Sanguisorbae Radix extract.Methods : The Sanguisorbae Radix extract was fermented byStreptococcus thermophilus,and their products was tested for antibacterial activity against pathogenic microorganisms namely,Bacillus cereus,Bacillus subtilis,Staphylococcus aureus,Escherichia coli,Vibrio parahaemolyticusandSalmonella typhimuriumby paper disc diffusion method and the antioxidant activities of extract was evaluated by five different assays as electron donating ability(EDA), superoxide dismutase(SOD)-like activity, polyphenol, flavonoid contents and nitrite scavenging ability.Results : The bio-fermented Sanguisorbae Radix extract was safe from heat. Antibacterial activity of fermented Sanguisorbae Radix extract appeared relatively highly againstBacillus cereusandStaphylococcus aureusand didn't show any difference. EDA in comparison to Vitamin C showed over 90% activity at about the same time of Sanguisorbae Radix extract expressed highly. SOD activity showed 15% in fermentation before and after. The nitrite scavenging ability of Sanguisorbae Radix extract before and after fermentation showed higher numerical value over 70% in pH 2.5 than that of butylated hydroxytoluene(BHT). But SOD activity, EDA and nitrite scavenging ability were not different between the Sanguisorbae Radix extract before and after fermentation. Total polyphenol content expressed over about 20 mg/g, and that of the Sanguisorbae Radix extracts was increased than that of the fermented Sanguisorbae Radix extracts.Conclusions : The results suggest the usefulness of developing functional materials using antioxidant active Sanguisorbae Radix extract was fermented bySalmonella typhimuriumwith high polyphenol contents and nitrite scavenging ability.