• 한국미생물·생명공학회지
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• 제27권1호
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• pp.46-53
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• 1999

The purpose of this study was to optimize the conditions of continuous mixed culture of C.butyricum and R. spaeroides K-7, which were able to produce hydrogen using biomass-dreived substrate. To investigate the possibility of continuous culture, semi-continuous culture was carried out for 20 days. In semi-continuous culture using the reactor system, the replacement rate of fresh medium was 30% of total medium volume for the highest hydrogen evolution. In continuous culture, the optimum dilution rate was determined to be 0.05$h^{-1}$. The continuous culture produced 3.1 times as compared with the hydrogen on batch culture. On the other hand, the continuous mixed culture produced 1.3~2.1 times as much as hydrogen of the continuous monoculture of C. butyricum. When 10g of glucose in the media (1l) was supplied as a carbon source on continuous culture, mixed culture of C. butyricum and R. sphaeroides K-7 increased hydrogen evolution rate. Because considerable amount of glutamate was contained in waste water of glutamate fermentation, utilization of glutamate was examined in mixed culture. As a result of examination, production of hydorgen was slightly inhibited by high concentration of glutamate, more than 20mM, on continuous monoculture of R. sphaeroides K-7. On the other hand, both on continuous monoculture of C. butyricum and on mixed culture of C. butyricum and R. sphaeroides K-7, production of hydrogen was not inhibited by high concentration of glutamate such as 100mM. Hence this suggests that high concentration of waste water can be used as good substrate for hydrogen production on monoculture of C. butyricum and mixed culture of C. butyricum and R. sphaeroides K-7.

• 한국미생물·생명공학회지
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• 제6권4호
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• pp.155-159
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• 1978

분리된 효모에 의한 aromatic ring compound의 전환반응 실험에 앞서 phenol 자화능에 대한 환경 인자의 영향을 조사하기 위하여 phenol을 유일한 탄소원으로 사용하여 분리된 효모균을 30시간, 3$0^{\circ}C$에서 진탕배양하여 균체증식량을 측정하였다. 1) pH3.5~4.5 온도 35$^{\circ}C$에서 가장 자화능이 우수하였으며 phenol의 처음 농도 1000ppm 까지 는 쉽게 이용할 수 있었고 2000ppm에서는 5 일간 배양시켰을 때 비로소 균체증식이 나타났다. 2) pH 5.0, 배양온도 3$0^{\circ}C$에서 본 균의 maximum specific growth rate는 0.27hr-1 이었으며, phenol 을 1000ppm씩 단계적으로 첨가하면서 phenol 소비율에 대한 균체수율 정수 Y값을 구한 결과 Y=3.2였다. 3) Yeast extract를 필수영양원으로 첨가할 때 0.005~0.01% 농도에서 가장 효과적이었으며, 또 산화환원소 효소 조해제인 HgCl$_2$, phenylhydrazine 을 명명 $10^{-5}$M, $10^{-3}$M을 배지내에 첨가하면 분리된 효모균의 증식을 거의 볼 수 없었다. 4) Phenol의 자화에 명종 실소원의 효과를 비교 해 본 결과 urea가 가장 효과적이었고, 이 효모균은 phenol 외에 catechol, resorcinol, benzidine 을 자화할 수 있다

• 한국미생물·생명공학회지
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• 제2권1호
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• pp.1-7
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• 1974

농산페자원을 기질로 하여 섬유소단세포단백을 생산하기 위해 전국에서 수집한 썩은 나무, 퇴비, 토양 등 시료에서 enrichment culture technique으로 172주의 섬유소자화세균을 분리하였다. 이들중 섬유소 자화력이 강한 균 6주를 동정하여 다음 결과를 얻었다. 1. 선별한 6주 중 5주는 Cellulomonas속이었으며 나머지 1주는 Sporocytophaga속이었다. 2. Sporocytophaga속의 세균은 microcyst가 타원형인 S. ellepsospora이었다. 3. Cellulomonas속의 세균들은 C.fimi 1균주, C.gelida 1균주, C. flavigena 2균주 및 C. aurogena 1 균주이 었다. 4. 분리균 C. aurogena는 5탄당인 arabinose 와 xylose를 자화하는 성질이 Bergey's Manual에 수록된 균과 달라 새로운 변종으로 판명되었다.

• 한국환경과학회지
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• 제8권4호
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• pp.451-456
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• 1999

Microorganisms utilizing petroleum as substrate were screened from the seawater in Pusan coastal area. Among them, fifty strains utilized bunker-A oil as a sole carbon and energy source. Five of these fifty strains were selected to experiment this study. According to the taxonomic characteristics of its morphological, cultural and biochemical properties, the selected stains were named Pseudomonas sp. EL-12, Flavobacterium sp. EL-15, Acinetobacter sp. EL-18, Enterobacter sp. EL-27 and Micrococcus sp. EL-43, respectively. The optimal medium compositions and cultural conditions for assimilation of bunker-A oil by the selected strains were 1.5-2% bunker-A oil, 0.1% $NH_4NO_3$, 1-1.5% $MgSO_4$.$7H_2O$, 0.05-0.15% KCl, 0.1-0.15% $CaCl_2$.$2H_2O$, 2.5-3.5% NaCl, initial pH 8-9, temperature 3$0^{\circ}C$ and aeration, respectively. The utilization and degradation characteristics on the various hydrocarbons by the selected stains were showed that bunker oil, n-alkane and branched alkane compounds were highly activity than cyclic alkane and aromatic hydrocarbon compounds.

• Journal of Microbiology and Biotechnology
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• 제15권4호
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• pp.800-808
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• 2005

Leuconostoc mesenteroides SY1, an isolate from kimchi, was able to ferment $\alpha$-galactosides, such as melibiose and raffinose. $\alpha$-Galactosidase ($\alpha$-Gal) activity was higher in cells grown on melibiose and raffinose than cells grown on galactose, sucrose, and fructose. $\alpha$-Gal activity was not detected in cells grown on glucose, indicating the operation of carbon catabolite repression (CCR). A 6 kb DNA fragment was PCR amplified using a primer set based on the nucleotide sequence of a putative $\alpha$-galactosidase gene (aga) from L. mesenteroides ATCC 8293. Nucleotide sequencing of the 6 kb fragment confirmed the presence of aga and other genes involved in the galactosides utilization, and the gene order was galR (transcriptional regulator)-aga-gaIK (galactokinase)-gaIT (galactose-1-phosphate uridylyltransferase). Northern blotting experiment showed that aga, gaIK, and gaIT constituted the same operon, that the transcription was induced by galactosides, such as melibiose and raffinose, whereas gaIR was independently transcribed as a monocistronic gene, and that the level of transcription was fairly constant. The aga was overexpressed in E. coli BL21 (DE3) using pET26b(+) vector, and $\alpha$-Gal was accumulated in E. coli as an inclusion body.

• Journal of Microbiology and Biotechnology
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• 제29권12호
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• pp.1904-1915
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• 2019

Resistant starch (RS) is metabolized by gut microbiota and involved in the production of short-chain fatty acids, which are related to a variety of physiological and health effects. Therefore, the availability of RS as a prebiotic is a topic of interest, and research on gut bacteria that can decompose RS is also important. The objectives in this study were 1) to isolate a human gut bacterium having strong degradation activity on non-gelatinized RS, 2) to characterize its RS-degrading characteristics, and 3) to investigate its probiotic effects, including a growth stimulation effect on other gut bacteria and an immunomodulatory effect. Bifidobacterium adolescentis P2P3 showing very strong RS granule utilization activity was isolated. It can attach to RS granules and form them into clusters. It also utilizes high-amylose corn starch granules up to 63.3%, and efficiently decomposes other various types of commercial RS without gelatinization. In a coculture experiment, Bacteroides thetaiotaomicron ATCC 29148, isolated from human feces, was able to grow using carbon sources generated from RS granules by B. adolescentis P2P3. In addition, B. adolescentis P2P3 demonstrated the ability to stimulate secretion of Th1 type cytokines from mouse macrophages in vitro that was not shown in other B. adolescentis. These results suggested that B. adolescentis P2P3 is a useful probiotic candidate, having immunomodulatory activity as well as the ability to feed other gut bacteria using RS as a prebiotic.

• 에너지공학
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• 제21권4호
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• pp.373-377
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• 2012

Among the fossil fuels, the brown coal is a great deal of resources. However, it is hardly used due to the high moisture content and low calorific value. It has both the week points such as spontaneous combustion and high volatile content and the strong points such as the low-sulfur and low ash content. If we overcome these week points, the using amount of brown coal would be increased. Also, it is well known that biomass is one of the important primary renewable energy sources because of carbon neutral energy. Furthermore, the utilization of biomass has been more and more concerned with the depletion of fossil fuel sources as well as the global warming issues. Combustion and thermal decomposition of biomass is one of the more promising techniques among all alternatives proposed for the production of energy from biomass. In this study, combustion of brown coals and mushroom waste was done. Mass change of samples and emission of hydrocarbon components were measured. As the results, we obtained combustion rate constant. Also activation energy was calculated in char combustion step. Hydrocarbon components were more generated in low oxygen concentration than high. Emission amount of hydrocarbon components in mushroom waste was significantly increased comparing to brown coal.

• 한국초지조사료학회지
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• 제16권1호
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• pp.1-8
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• 1996

The objective of this study is to obtain the basic data for investigating the effects of organic reserves on winter survial or regrowth yield. Forage rape (Brussicu napus L.) was sown at 10 day> interval from Sep. I to Nov. 1. Field-grown palnts were sampled on the before wintering (Dec. 4) and on the wintering period (Jan. 16) to analyze the nitrogen and non-structural cahohydrate reserves. The rate of winter survival and regrowth yield were also measured in the spring of next year. On the before wintering, the dry matter yields from the plots sown on Sep. 1, Sep.11 and Sep. 21 were 860, 596 and 260 kg/lOa, respectively. No. harvest was canied out on the plots sown after Oct. 1 because the growth state was not enough to cut. Both of nitrogen and starch contents per plant significantly increased as the seeding date was later. On the wintering period, the contents of nitrogen reserves in roots were 176.8. 120.1, 71.7, 84.0, 72.1, 45.3 and 33.3 mg/plant, those of starch reserves were 199.0. 55.8, 21.8, 92.6, 86.5, 36.4 and 29.0 mglplant, resepctively, in the plots sown on Sep. 1, Sep. 11, Sep. 21, Oct. I, Oct. 11, Oct. 21 and Nov. 1. The rates of winter survival were 40, 36, 33, 85, 87, 59 and 49% and regrowth yields were 161, 86, 65, 520, 451, 121 and 33 kgD.M/lOa, respectively, in each plots. 'Ihese results clearly showed that seeding date has a close influence on the level of organic reserves and forage yield, and that the possibility of continuous utilization on the before and alter wintering is extremely limited by seeding date.

• Journal of Microbiology and Biotechnology
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• 제17권6호
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• pp.1054-1057
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• 2007

Lipases are industrially useful versatile enzymes that catalyze numerous different reactions including hydrolysis of triglycerides, transesterification, and chiral synthesis of esters under natural conditions. Although lipases from various sources have been widely used in industrial applications, such as in food, chemical, pharmaceutical, and detergent industries, there are still substantial current interests in developing new microbial lipases, specifically those functioning in abnormal conditions. We screened 17 lipase-producing yeast strains, which were prescreened for substrate specificity of lipase from more than 500 yeast strains from the Agricultural Research Service Culture Collection (Peoria, IL, U.S.A.), and selected Yarrowia lipolytica NRRL Y-2178 as a best lipase producer. This report presents new finding and optimal production of a novel extracellular alkaline lipase from Y. lipolytica NRRL Y-2178. Optimal culture conditions for lipase production by Y. lipolytica NRRL Y-2178 were 72 h incubation time, $27.5^{\circ}C$, pH 9.0. Glycerol and glucose were efficiently used as the most efficient carbon sources, and a combination of yeast extract and peptone was a good nitrogen source for lipase production by Y. lipolytica NRRL Y-2178. These results suggested that Y. lipolytica NRRL Y-2178 shows good industrial potential as a new alkaline lipase producer.

• 한국응용과학기술학회지
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• 제35권3호
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• pp.876-885
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• 2018

폐 RHDM(Residue Hydrodemetallation) 촉매상에 침적된 비활성화 성분인 탄소, 황 을 고온배소 처리하여 제거한 후, 과량 침적되어 있는 바나듐은 초음파 교반기에서 5~15wt% 옥살산 수용액을 이용하여 $50^{\circ}C$, 5분 조건하에 바나듐 추출량을 조절함으로써 NOx 저감을 위한SCR(Selective Catalytic Reduction) 촉매로의 적용 가능성을 확인하고자 하였다. 폐촉매와 단계별 처리된 RHDM 촉매를 대상으로 상압반응기상에서 NOx 저감 효율을 측정하였고, 촉매의 성분분석은 ICP, C & S analyzer 및 XRF를 이용하여 분석하였다. 10wt% 옥살산 수용액으로 바나듐을 침출한 촉매가 가장 안정적이었으며 높은 NOx 저감 효율을 보였다. 이를 메탈폼 형태의 지지체에 워시코팅한 촉매는 상용 SCR 촉매와 동등 수준의 NOx 저감 효율을 나타내었다. 따라서 폐 RHDM 촉매의 처리 조건 조정에 관한 후속 연구를 통하여 각 적용처에 적합한 SCR 촉매로의 이용 가능성은 충분할 것으로 사료된다.