• 한국물환경학회지
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• 제26권6호
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• pp.976-985
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• 2010

In this study, characteristics of dissolved organic matter (DOM) from Lake Paldang and seven other DOM sources (lake plankton, plants, soil, composite, treated sewage) were studied using XAD resin fractionation and 28-day microbial incubation experiment. Distribution patterns of DOM-fractions, which include hydrophilic acids (HiA), hydrophilic bases (HiB), hydrophilic neutrals (HiN), hydrophobic acids (HoA), hydrophobic neutrals (HoN) and the extent of DOM biodegradation (i.e., biodegradability) were different depending on the origins of the DOM samples. The DOM distribution pattern and the biodegradability were found to be effective for distinguishing the different DOM sources. The biodegradability (%) had negative correlations with the content (%) of hydrophobic fractions (Ho) and specific UV absorbance of DOM, which indicate that the Ho fractions contain more aromatic carbon structures and relatively stable during biodegradation, irrespective of the sources. To gain additional insight into the microbial transformation of the DOM, we also investigated the changes in the fraction's distribution for plankton, leaf litter and composite samples after the incubation. The results showed that biodegradation of hydrophilic fraction (Hi) causes an increase in the proportion of Ho (HoA, HoN), while biodegradation of HoA increases the HoN production.

• KSBB Journal
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• 제19권3호
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• pp.236-240
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• 2004

Batch experiment에서 다양한 질소 농도에서 구해진 질소제거 속도와 비 생장속도 등의 데이터를 토대로 4.6일의 체류시간을 갖는 2단 처리 장치를 설계하였다. 그리고 continuous experiments에서는 3.5일의 체류시간을 갖는 2단의 처리 장치를 설계하였다. 두 가지 값에 차이는 있지만 실제 현장에서 폐수 처리 장치를 설계할 때 충분한 자료가 되리라고 판단한다. 따라서 위의 결과를 토대로 기존 시스템에 미세조류 시스템을 부가한다면 기존공정의 단점인 잉여질소 제거 장치로서 충분히 역할을 수행해 배출 기준치를 만족시키는 안전한 폐수처리장치가 되리라고 판단한다.

• 한국식품영양학회지
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• 제12권5호
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• pp.470-477
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• 1999

The purpose of this study was to choose prinicipal food components contained in diet foods and food additives used for manufacturing processed foods and elucidate their in vivo effects on the growth pattern of Helicobacter pylori. To do this the antibacterial effects of various sources of carbon nitrogen and mineral as an effect agent on Helicobacter pylori were first assessed based upon bacterial growth degree. results show that the source of carbon tested had different effects on bacterial growth of Helicobacter pylori. It was revealed that a promotional effect of monosaccharides resulted in enhanced growth of Helicobacter pylori compared with disaccharides and polysacchrides, in particular glucose was observed to be most effective in growth of Helicobacter pylori among monosaccharides teste whereas mannose to hinder the growth of Helicobacter pylori. Polyols such as sorbitol mannitol maltitol and xylitol was however observed to show no promotion or suppression effect on growth of Helicobacter pylori. Apart from these the sources of amino acid and inorganic nitrogen were chosen and tested to assess the promotion or suppression effect of nitrogen sources on growth of helicobacter pylori. It was found that amino acid such as lysine showed its promotion effect on the growth of Helicobacter pylori while arginine (NH4)2SO4 and NH4Cl showed no effect on its growth. Ammoia and urea were however observed to have a positive effect on the growth of Helicobacter pylori. Among these effect agents lysine and methionine were revealed to show the most positive effect on growth of Helicobacter pylori. Minerals such as MgSO4 KH2PO4 and MgCl2 appered to exert their positive growth effects whereas CaCl2 and CaSo4 had a little effect. In addition FeSO4 FeCl2 and FeCl3 brought suppression on the growth of helicobacter pylori. In studies of the growth of Helicobacter pylori by food additives ascorbic acid showed extreme suppression on its growth,. Sodium nitrate and sodium chloride were also found to be of negative effect on the growth of Helicobacter pylori in rder of degree whereas tocopherol had nothing to do with microbial growth.

• 한국대기환경학회지
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• 제12권4호
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• pp.429-439
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• 1996

A comprehensive air quality monitoring was carried out in this study to investigate the concentrations of criteria air pollutants in indoor and outdoor air of public facilities in Taegu area. Four different kinds of public facilities were seleced as sampling sites, which are underground stores, stations & terminals, general hospitals, and department stores. Each group of the public facilities was consisted of three different sampling sites. As a consequence, a total of 12 different sampling sites were surveyed throughout this study. Sampling was conducted simultaneously indoors, three times per day (in the morning, afternoon, and evening) and four times per year (spring, summer, fall, and winter) at each sampling site during the period of October 1994 to July 1995. A range of criteria pollutants were measured in order to obtain a broad profile of indoor and ambient air quality, including total suspended particles (TSP), carbon monoxide (CO), carbon dioxide ($CO_2$), formaldehyde (HCHO), sulfur dioxide ($SO_2$), and nitrogen dioxide ($NO_2$). In addition, temperature, relative humidity, and air current were measured on site together with those air pollutants. Results of this study indicated that the indoor levels of TSP, CO, $SO_2, and NO_2$ appeared to be generally higher in stations/terminals and underground stores than those in department stores and hospitals. However, HCHO and $CO_2$ were found to have higher levels in the department stores and hospitals than other places, indicating that the effects of indoor sources for these pollutants are significantly different from other combustion related pollutants such as TSP, CO, and $SO_2$. It was also found that there are marked seasonal and daily variations both in indoor and outdoor air quality. In general, combustion related pollutants such as CO, $SO_2$ and $NO_2$ showed a typical pattern of higher levels in winter than insummer, and also higher in the morning and/or in the evening than in the afternoon. However, the seasonal and daily patterns of HCHO appeared to be opposite to the combustion related pollutants, i.e., higher both in summer and in the afternoon, implying the effect of temperature on the volatilization from indoor sources of HCHO. Results of correlation analyses between indoor and outdoor air quality also indicated that the effects of outdoor sources on the indoor levels of TSP, $SO_2$, CO, and $NO_2$ and much significant, whilst no significant correlations between indoor and outdoor levels were found for HCHO and $CO_2$.

• Carbon letters
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• 제24권
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• pp.47-54
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• 2017

Different phytochemicals obtained from various natural plant sources are used as reduction agents for preparing gold, copper, silver and platinum nanoparticles. In this work a green method of reducing graphene oxide (rGO) by an inexpensive, effective and scalable method using olive leaf aqueous extract as the reducing agent, was used to produce rGO. Both GO and rGO were prepared and investigated by ultraviolet and visible spectroscopy, Fourier-transform infrared, scanning electron microscopy, atomic force microscopy, thermogravimetric analysis, cyclic voltammetry, X-ray photoelectron spectra, electrochemical impedance spectroscopy and powder X-ray diffraction.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권6호
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• pp.546-551
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• 2005

[ ${\beta}-1,3-Glucan$ ] (curdlan) is a water-insoluble polysaccharide composed exclusively of ${\beta}-1,3\;linked$ glucose residues. Extracellular curdlan was mostly synthesized by Agrobacterium species and Alcaligenes faecalis under nitrogen-limiting conditions. In this study, we screened the microorganisms capable of producing extracellular curdlan from soil samples. For the first time, we reported Gram-positive bacterium Bacillus sp. SNC 107 capable of producing extracellular curdlan in appreciable amounts. The effect of different carbon sources on curdlan production was studied and found that the yield of curdlan was more when glucose was used as carbon source. It was also found that maximum production was achieved when the initial concentration of ammonium and phosphate in the medium was 0.5 and 1.9 g/L respectively. In this study the curdlan production was increased from 3 to 7g/L in shake flask cultures.

• 자원ㆍ환경경제연구
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• 제9권3호
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• pp.489-513
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• 2000

This paper introduces a new method to estimate and decompose sources of carbon dioxide emissions using an input-output model with decomposition method free of residual usually associated with this kind of analysis. This method is different from others, using what we call 'mean rate-of-change index (MRCI)' for weights of the decomposed terms. Ang et al.(1998) asserted that logarithmic mean divisia index(LMDI) is superior to Laspeyres index(LI) or simple average divisia index(SADI) since it reduces residual to zero. We claim that our method is an improvement over the other methods because it enables residual free decomposition even when data contain negative values, the case which LMDI cannot handle. We demonstrate by way of showing some examples that our method is superior to LI, SADI(Proops, 1993 and Chung, 1998) or LMDI(Ang et al., 1998).

• Food Science and Biotechnology
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• 제18권6호
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• pp.1365-1370
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• 2009

Aspergillus kawachii extracellular pectinases were screened in liquid cultures with different carbon sources. The fungus grown on citrus pectin or lemon pomace produced at least one of these inducible pectinases: acidic polygalacturonase, pectin lyase, pectin methylesterase, $\alpha$-L-arabinofuranosidase, $\alpha$-1,5-endoarabinase, $\beta$-D-galactosidase/exogalactanase, and $\beta$-1,4-endogalactanase. The lemon-pomace filtrates also contained significant $\alpha$-L-rhamnosidase and $\beta$-D-fucosidase activities. Most of the screened pectinases were active at pH 2.0-2.5, indicating that the A. kawachii enzymes were acidophilic. Under the culture conditions employed we could not detect enzymatic degradation of soybean rhamnogalacturonan. The A. kawachii pectinase-production-related regulatory phenomena of induction-repression resemble those described for other Aspergillus sp.

• 생명과학회지
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• 제28권8호
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• pp.969-976
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• 2018

본 연구에서는 Aspergillus niger 유래 TG의 최적 생산 조건을 연구하기 위해, A. niger 6 종을 이용하여 감자전분 1.5%, 효모추출물 1.0%, $KH_2PO_4$ 0.1%, 40%(v/v) volume의 배지를 기본 조성으로 하는 배지를 사용하였다. 기본 조성의 배지의 초기 pH를 달리하여 $30^{\circ}C$, 150 rpm의 조건으로 20일 동안 5일 간격으로 배양을 하여 TG 활성을 측정한 결과 초기 pH 5.0, 배양 15일, 그리고 A. niger KCTC6913 균주에서 가장 높은 TG 활성을 확인하였다. TG 생산에 유리한 탄소원, 질소원을 확립하기 위해 5 종의 다른 탄소원(감자 전분, 고구마 전분, 옥수수 전분, 밀 전분, 덱스트린) 또는 3종의 다른 질소원(효모추출물, 맥아추출물 및 쇠고기추출물)을 이용하여 초기 pH 5.0, 15일 배양한 후 TG 활성을 측정한 결과, 기본 조성 배지인 감자 전분 및 효모추출물에서 가장 높은 TG 활성을 확인 하였다. 또한 A. niger KCTC6913 균주는 호기적 조건 및 탄소원:질소원의 비율을 조절함에 따라 TG 생산이 증가함을 확인하였다. 확립된 최적 배지 및 배양 조건에서 TG 활성을 평가하기 위해 기본배지 및 A. niger 배양에 널리 이용되는 PDB 배지를 대조군으로 하여 비교한 결과 기본 조성의 배지에 비해 1.3배, PDB 배지에 비해 4배 높은 TG 활성을 확인 하였다. 종합적으로 이러한 연구결과는 A. niger 유래의 TG를 산업적으로 이용하기 위한 최적 배양 배지 및 배양 조건을 성공적으로 수립하였음을 시사한다.

• Mycobiology
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• 제33권1호
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• pp.15-18
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• 2005

Macrolepiota procera, one of edible mushrooms belongs to Agaricaceae of Basidiomycota, has a good taste and good medicinal value. As a preliminary study for the development of artificial cultivation method of edible mushroom, cultural characteristics of M. procera was investigated on various culture media under different environmental conditions. Mycelial growth was compared on culture media composed of various carbon and nitrogen sources, and C/N ratios. The optimal conditions for the mycelial growth were $30^{\circ}C$ and pH 7. M. procera showed the rapid mycelial growth in the PDA media. The optimal carbon and nitrogen sources were maltose and glycine, respectively. The optimum C/N ratio was about 10 : 1 in case that 1% glucose was supplemented to the basal media as carbon source.