• 미생물학회지
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• 제40권3호
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• pp.248-253
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• 2004

2000년 9월부터 2002년 12월 사이에 바이칼호에서 분리된 빈영양성 세균 168균주와 저온성 세균 132균주를 대상으로 BIOLOG Microplate를 이용하여 탄소원의 이용특성을 조사하였다. 본 연구에 사용된 빈영양성 세균 중 oxidase 양성 (GN-NENT 그룹)의 86% (56균주)와 oxidase음성 (GN-ENT그룹)의 89% (92균주), 저온성 세균 중 oxidase 음성 (GN-ENT 그룹)의 82% (85균주)는 다앙한 탄소원 중에서 $\alpha$-D-glucose를 이용할 수 있었으며, 저온성 세균 중 oxidase 양성 (GN-NENT 그룹)의 93% (26 균주)는 bromosuccinic acid를 이용하였다. $\alpha$-D-lactose는 빈영양성 GN-ENT 그룹의 일부만이 이용하였으며 나머지 균주들은 전혀 이용하지 못하였다. BIOLOG Microplate를 이용하여 동정된 균들을 속별로 살펴보면, Pseudomonas속이 49균주로 가장 많았으며, 그 외에도 Salmonella 속, Serratia속, Buttiauxella 속, Pantoea 속, Yersinia 속, Brevundimonas 속, Hydrogenophaga 속, Photorhabdus 속, Sphingomonas 속, Xenorhabdus 속이 동정되었다.

• 한국미생물·생명공학회지
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• 제23권6호
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• pp.702-709
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• 1995

Degradation Of $\kappa $-carrageenan-based film by microorganisms screened from carrageenan source and activated sludge of a carrageenan producing factory was investigated by measuring changes of pH, viscosity, total sugar and total organic carbon (TOC) of the medium containing $\kappa $-carrageenan as a carbon source. Initially fifteen strains of microorganism were isolated from carrageenan source and activated sludge and then three organisms among them were selected based on the ability of growing in the medium including 0.3% $\kappa $-carrageenan as a sole carbon source. They were identified as Escherichia coli, Saccharomyces cerevisiae and Aspergillus niger. As indices of biodegradability Of $\kappa $-carrageenan based film, the changes of pH, viscosity, total sugar, and TOC of the carrageenan film-based medium were tested by the cultivation of single or mixed strains of the identified organisms. Mixed culture showed the highest biodegradability, which resulted in the changes of pH from 6.5 to 3.0, viscosity from 164 cps to 15.6 cps, total sugar content from 2.35 g/l to 0.53 g/l and TOC from 5721 ppm to 232 ppm after 30 days of cultivation. The biodegradability determined as the reduction rate of TOC by pure cultures of Asp. niger, E. coli, Sacch. cerevisiae and mixed culture of the three organisms were 94%, 86%, 80% and 96%, respectively.

• Journal of Microbiology and Biotechnology
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• 제12권5호
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• pp.722-728
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• 2002

Eight strains producing bacterial cellulose (BC) were isolated from rotten fruits and traditionally fermented vinegars. One of the isolated strains from the rotten grape in Gwangju, Korea, maintained a relatively stable BC production in shaking cultures. This isolated strain proved to be Acetobacter xylinum, based on several biochemical and morphological tests. It was shown that the slant-baffled flask was more efficient than the conventional flask for the BC production in shaking cultures. To determine the most suitable carbon and nitrogen sources for the production of BC, various compounds were examined. Fructose was found to be the most effective carbon source with an optimal concentration of 2%. Mixed carbon source (glucose:fructose=1:3) was also better than glucose or fructose alone. Optimal nitrogen source, when basal medium was used, was 10% (v/v) com steep liquor (CSL). When com steep liquor was used with a mixed carbon source (glucose:fructose=1 :3),4% CSL exhibited the best BC production. Based on these results, a defined medium was developed for the BC production by Acetobacter xylinum KJ-1. When this medium was used under optimal culture conditions, the BC production was 7.2 g/1, which was approximately 3 times higher than that with the traditional HS medium.

• KSBB Journal
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• 제30권1호
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• pp.33-37
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• 2015

Recently, several health benefits of rice wine, makgeolli, were known due to the interest on the traditional Korean liquor and the researches on the rice wine are increasing. Organic acids produced during the process of rice wine fermentation play important roles in the taste and flavor. In this study, we have examined the optimal conditions for lactic acid production in rice koji as a carbon source. Skim milk was also used as a supplementary ingredient for the optimization of lactic acid fermentation. Bacterial growth of Lactobacillus sakei was monitored under this condition. The pH, acidity of the culture and the ethanol tolerance of this bacterium were also tested. Through these experiments, we were able to optimize the growth condition of lactic acid bacteria by the addition of skim milk. This was also able to affect the change of pH, acidity, sugar concentration and alcohol tolerance, which might contribute to the improvement of the quality of rice wine. The optimal condition for the growth was 2 days with 10% (w/v) of skim milk concentration. With these results, it was confirmed that rice koji was an effective carbon source for the growth of lactic acid bacteria.

• 환경위생공학
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• 제23권2호
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• pp.27-33
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• 2008

Using crude soybean oil as the sole carbon source, the lincomycin production from Streptomyces lincolnensis LC 345 was investigated in the air lift bioreactor. When 30 g/L of crude soybean oil was used, the maximum lincomycin concentration reached 0.89 g/L, after 5 days of culture. When CSL concentration was increased from 10 to 30 g/L, Lincomycin concentration was increased from 0.6 to 1.2. On the other hand, when CSL concentration was increased from 40 to 60 g/L, it was decreased from 1.15 to 0.7 g/L. Using these results, fed batch cultures for comparing the use of crude soybean oil and glucose as a conventional carbon source were carried out in a 5 L air lift bioreactor. When crude soybean oil was used as the sole carbon source, the maximum lincomycin concentration was 2.0 g/L, which was about 2.0 fold higher than that of glucose medium after 7 day of culture. The product yield from olive oil was 0.042 g/g consumed carbon source, which was about 3.8 fold higher than that of glucose.

• 한국재료학회지
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• 제18권10호
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• pp.564-570
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• 2008

Nanostructured carbon materials have been found to have applications in fuel cell electrodes, field emitters, electronic devices, sensors and electromagnetic absorbers, etc. Especially, the CNF (carbon nanofiber) can be expected to play an important role in catalyst supporters for fuel cell electrodes and chemical reactions. In this study, we synthesized CNF from a liquid phase carbon source by a solvothermal method. In addition, we studied the parameters for the preparation of CNF by controlling heating and cooling rates, synthesis temperature and time. We characterized the CNF by SEM/TEM, XRD, Raman spectroscopy and EDS. We found that the heating and cooling rate have strong effects on the CNF formation and growth. We were able to prepare the best CNF at the heating rate of $10^{\circ}$/min, at $450^{\circ}$ for 60 minutes, and at the cooling rate of $4^{\circ}$/min. As a result of Raman spectra, we found that the sample showed two characteristic Raman bands at ${\sim}1350cm^{-1}$ (D band) and ${\sim}1600cm^{-1}$ (G band). The G band indicates the original graphite feature, but the D band has been explained as a disorder feature of the carbon structure. The diameter and length of the CNF was about $15{\sim}20nm$, and over $1{\mu}$, respectively.

• Journal of Information Display
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• 제2권3호
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• pp.48-53
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• 2001

Carbon nanotube emitters, prepared by screen printing, have demonstrated a great potential towards low-cost, largearea field emission displays. Carbon nanotube paste, essential to the screen printing technology, was formulated to exhibit low threshold electric fields as well as an emission uniformity over a large area. Two different types of triode structures, normal gate and undergate, have been investigated, leading us to the optimal structure designing. These carbon nanotube FEDs demonstrated color separation and high brightness over 300 $cd/m^2$ at a video-speed operation of moving images. Our recent developments are discussed in details.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 추계학술대회
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• pp.147-152
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• 2004

선박에서 발생되는 오${\cdot}$폐수를 처리하기 위하여 생물학적 영양염류 제거공정에서 질소와 인 등의 제거효율은 유기물의 양과 구성성분에 따라 영향을 받는 경향이었다. 선박에서 발생되는 음식폐기물을 이용하여 생성된 산발효액을 이용하여 영양염류를 효율적으로 제거하기 위한 외부탄소원으로 사용하여 산발효액의 적용성을 평가하였다. 음식폐기물 산발효액의 탈질율을 평가한 결과 질산성 질소가 완전히 제거되는 시간은 140분이였고, 탈질속도는 0.30g $NO_3-N/g\;VSS{\cdot}day$로 나타났다. 산발효액의 주입으로 인하여 유출수 중의 $COD_cr$ 농도가 증가함을 알 수 있었는데 이것은 산발효액에 존재하는 유기물을 미생물이 다 이용하지 못하는 부분이 존재하고 주입량의 증가에 따른 유출수 중의 $COD_cr$ 농도를 증가시켰다. 암모니아성 질소의 성상은 산발효액의 첨가에 크게 영향을 받지 않았으며 산화된 질소의 변화는 산발효액 주입량이 증가할수록 무산소단계에서 농도가 감소하여 전체 제거효율이 증가함을 볼 수 있었다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권1호
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• pp.72-79
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• 2006

Kojic acid production by Aspergillus flavus strain S44-1 using sucrose as a carbon source was carried out in a 250-mL shake flask and a 2-L stirred tank fermenter. For comparison, production of kojic acid using glucose, fructose and its mixture was also carried out. Kojic acid production in shake flask fermentation was 25.8 g/L using glucose as the sole carbon source, 23.6 g/L with sucrose, and 6.4 g/L from fructose. Reduced kojic acid production (13.5 g/L) was observed when a combination of glucose and fructose was used as a carbon source. The highest production of kojic acid (40.2 g/L) was obtained from 150 g/L sucrose in a 2 L fermenter, while the lowest kojic acid production (10.3 g/L) was seen in fermentation using fructose as the sole carbon source. The experimental data from batch fermentation and resuspended cell system was analysed in order to form the basis for a kinetic model of the process. An unstructured model based on logistic and Luedeking-Piret equations was found suitable to describe the growth, substrate consumption, and efficiency of kojic acid production by A. flavus in batch fermentation using sucrose. From this model, it was found that kojic acid production by A. flavus was not a growth-associated process. Fermentation without pH control (from an initial culture pH of 3.0) showed higher kojic acid production than single-phase pH-controlled fermentation (pH 2.5, 2.75, and 3.0).

• Journal of Microbiology and Biotechnology
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• 제18권11호
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• pp.1773-1784
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• 2008

Effects of various industrially important carbon sources (glucose, sucrose, xylose, gluconate, and glycerol) on shikimic acid (SA) biosynthesis in Escherichia coli were investigated to gain new insight into the metabolic capability for overproducing SA. At the outset, constraints-based flux analysis using the genome-scale in silico model of E. coli was conducted to quantify the theoretical maximum SA yield. The corresponding flux distributions fueled by different carbon sources under investigation were compared with respect to theoretical yield and energy utilization, thereby identifying the indispensable pathways for achieving optimal SA production on each carbon source. Subsequently, a shikimate-kinase-deficient E. coli mutant was developed by blocking the aromatic amino acid pathway, and the production of SA on various carbon sources was experimentally examined during 51 batch culture. As a result, the highest production rate, 1.92 mmol SA/h, was obtained when glucose was utilized as a carbon source, whereas the efficient SA production from glycerol was obtained with the highest yield, 0.21 mol SA formed per mol carbon atom of carbon source consumed. The current strain can be further improved to satisfy the theoretically achievable SA production that was predicted by in silico analysis.