• Transactions of the Korean hydrogen and new energy society
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• v.16 no.2
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• pp.111-121
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• 2005

이 연구는 광화학적 물분해 수소제소 기술의 일환으로 수행 중인 광촉매와 바이오촉매를 복합한 시스템 활용 기술에서 광촉매가 갖는 물리적 특성의 영향을 파악하고자 진행되었다. 다양한 물리적 특성을 갖는 광촉매 얻기 위하여 상용광촉매, 수열화법(HT-TiON), 리고 저온합성법(LT-TiON) 등을 이용하여 샘플을 준비하였다. 가시광 감응을 위하여 암모니아나 triethylamine 처리를 하여 질소를 도핑도 시도하였다. 시도된 복합시스템은 인위적인 전자주개 없이 수소를 발생시키는 결과를 보여주었으나, 광촉매로부터 엔자임으로의 전자전달 부분이 율속단계로 확인되었다. 사용된 광촉매 샘플에 따라 수소발생량에 차이가 나타난 결과로 광촉매의 미세구조 (결정상, 결정도, 기공 크기 및 비표면적 등)이 중요한 역할을 하는 것으로 판단되었다. 얻어진 결과들을 활용하여 재료들이 고정화된 새로운 시스템 구성을 제안하였다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.5
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• pp.808-813
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• 2002

This study investigated the effects of different kinds of dietary fibers, cellulose, psyllium husk, pectin and the Psyllium husk Plus Pectin, on the lipid concentration and hernobiochemical enzyme activity in male Sprague-Dawley rats. The experimental groups were divided into four groups : the cellulose group, the psyllium husk group, the pectin group and the psyllium husk Plus Pectin group. Dietary fiber was supplemented at 10% (w/w) levels in the diet. Body weight gain, food intake and relative tissue seight were not significantly different among the dietary groups. Concentrations of triglyceride and phospholipid of serum in the psyllium husk and the pectin groups were significantly lower than those of the cellulose and the psyllium husk plus pectin groups. Concentration of total cholesterol of serum in the psyllium husk plus pectin group was lower than other dietary groups. However, concentrations of triglyceride and phospholipid of liver in the psyllium husk and the pectin groups were significantly higher than those of the cellulose and the psyllium husk plus pectin groups. The hemobiochemical Parameters, total protein, albumin, glutamic pyruvic transaminase, glutamic oxaloacetic transaminase, alkaline phosphatase, lactate dehydrogenase and blood urea nitrogen in serum of the psyllium husk group were lower than other dietary groups. These results showed that dietary psyllium husk could have lowering effects on serum triglyceride concentration without any side effect of hemobiochemical enzyme activity in rats.

• Microbiology and Biotechnology Letters
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• v.13 no.3
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• pp.257-263
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• 1985

Rhodopseudomonas sp. KCTC 1437 evolved molecular hydrogen efficiently under light illuminated anaerobic culture condition in the presence of organic acids and various sugars. especially glucose when low concentration of NH$_4$ + or L-glutamate was added to cultures. It was revealed that hydrogen formation from Rhodopseudomonas sp. KCTC 1437 was mediated by two different enzyme systems. Under the nitrogen limiting condition, hydrogen evolution from glucose was catalyzed by nitrogenase. For the nitrogenase activation in vivo, the precultured cells drown on limiting concentration of NH$_4$$^{+}$ as a sole nitrogen source showed more capacity of hydrogen evolution from glucose in the presence of L-glutamate than any other cells .frown on sufficient concentration of NH$_4$$^{+}$, L-glutamate, NH$_4$$^{+}$, or both of L-glutamate and $N_2$. A significant volume of molecular hydrogen was evolved from glucose even in the presence of excess NH$_4$$^{+}$ either in the light or dark anaerobic condition, presumably due to the mediation of hydrogen evolution by fromic hydrogenlyase.enlyase.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.6
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• pp.482-493
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• 2005

Biomass is originally photosynthesized from inorgainic compounds such as $CO_2$, minerals, water and solar energy. Recent studies have shown that anaerobic bacteria have the ability to convert recalcitrant biomass such as cellullosic or chitinoic materials to useful compounds. The biomass containing agricultural waste, unutilized wood and other garbage is expected to utilize as feed, food and fuel by microbial degradation and other metabolic functions. In this study we isolated several anaerobic, cellulolytic and chitinolytic bacteria from rumen fluid, compost and soil to study their related enzymes and genes. The anaerobic and cellulolytic bacteria, Clostridium thermocellum, Clostridium stercorarium, and Clostridium josui, were isolated from compost and the chitinolytic Clostridium paraputrificum from beach soil and Ruminococcus albus was isolated from cow rumen. After isolation, novel cellulase and xylanase genes from these anaerobes were cloned and expressed in Escherichia coli. The properties of the cloned enzymes showed that some of them were the components of the enzyme (cellulase) complex, i.e., cellulosome, which is known to form complexes by binding cohesin domains on the cellulase integrating protein (Cip: or core protein) and dockerin domains on the enzymes. Several dockerin and cohesin polypeptides were independently produced by E. coli and their binding properties were specified with BIAcore by measuring surface plasmon resonance. Three pairs of cohesin-dockerin with differing binding specificities were selected. Two of their genes encoding their respective cohesin polypeptides were combined to one gene and expressed in E. coli as a chimeric core protein, on which two dockerin-dehydrogenase chimeras, the dockerin-formaldehyde dehydrogenase and the dockerin-NADH dehydrogenase are planning to bind for catalyzing $CO_2$ reduction to formic acid by feeding NADH. This reaction may represent a novel strategy for the reduction of the green house gases. Enzymes from the anaerobes were also expressed in tobacco and rice plants. The activity of a xylanase from C. stercorarium was detected in leaves, stems, and rice grain under the control of CaMV35S promoter. The digestibility of transgenic rice leaves in goat rumen was slightly accelerated. C. paraputrificum was found to solubilize shrimp shells and chitin to generate hydrogen gas. Hydrogen productivity (1.7 mol $H_2/mol$ glucos) of the organism was improved up to 1.8 times by additional expression of the own hydrogenase gene in C. paraputrficum using a modified vector of Clostridiu, perfringens. The hydrygen producing microflora from soil, garbage and dried pelletted garbage, known as refuse derived fuel(RDF), were also found to be effective in converting biomass waste to hydrogen gas.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.675-681
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• 1997

This study was conducted to investigate the effect of dietary protein and fiber levels on the activities of ethanol metabolizing enzymes of liver in ethanol-treated rats. Sprague-Dawley male rats were fed on diets containing two levels of protein(7, 20%/kg diet) and pectin(5, 10%/kg diet). In ethanol experiments, ethanol(25% v/v) was administered by oral intubation(5g/kg body weight) at the same time once a day Control animals received an isocaloric dose of sucrose. The rats were sacrificed after 5 weeks of feeding periods. Alcohol dehydrogenase and microsomal ethanol oxidizing system activities of hepatic tissue were increased more in ethanol-treated groups than in control groups. Increment of activities predominated in normal protein normal fiber group. Aldehyde dehydrogenase activity was decreased in ethanol-treated groups and significantly decreased in normal Protein normal fiber group. Cytochrome P-450 content was significantly increased in ethanol-treated groups and Predominated in normal protein groups. Xanthine oxidase activity was increased in ethanol-treated groups, but not significantly except normal protein normal fiber group. Glutathione content tended to increase in proportion to level of dietary protein and was higher in normal fiber groups than in high fiber groups, whereas it was decreased by ethanol treatment. Lipid Peroxide content was significantly increased in low Protein normal fiber groups.