• Journal of Microbiology and Biotechnology
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• 제18권6호
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• pp.1130-1135
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• 2008

The effect of pH on anaerobic hydrogen production was investigated under various pH conditions ranging from pH 3 to 10. When the modified Gompertz equation was applied to the statistical analysis of the experimental data, the hydrogen production potential and specific hydrogen production rate at pH 5 were 1,182 ml and 112.5 ml/g biomass-h, respectively. In this experiment, the maximum theoretical hydrogen conversion ratio was 22.56%. The Haldane equation model was used to find the optimum pH for hydrogen production and the maximum specific hydrogen production rate. The optimum pH predicted by this model is 5.5 and the maximum specific hydrogen production rate is 119.6 ml/g VSS-h. These data fit well with the experimented data($r^2=0.98$).

• Journal of Plant Biotechnology
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• 제5권2호
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• pp.131-135
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• 2003

Callus and cell suspension cultures of Eurycoma longifolia Jack were initiated from leaves of different trees. The leaf explant of tree Eu9 produced the most calli and also induced high cell biomass in the cell suspension culture. Optimum production of cell biomass could be initiated in proliferating culture medium with a pH of 5.75 prior to autoclaving. The effects of macronutrient inorganic salts of Murashige and Skoog (MS) liquid medium supplemented with X on production of cell biomass of Eurycoma longifolia were also investigated. The highest cell biomass was produced in MS medium containing macronutrients of $21\;mM\;NH_4NO_3,\;12.25\;mM\;KNO_3,\;3.00\;mM\;CaCl_2.2H_2O,\;0.575\;mM\;MgSO_4.7H_2O$, and $1.83\;mM\;KH_2PO_4$. A new medium labeled as TAM was formulated for the production of Eurycoma longifolia cell biomass in the cell suspension culture.

• Journal of Microbiology and Biotechnology
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• 제28권5호
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• pp.732-738
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• 2018

Novel carbon-based solid acid catalysts were synthesized through a sustainable route from lipid-extracted microalgal residue of Dunaliella tertiolecta, for biodiesel production. Two carbon-based solid acid catalysts were prepared by surface modification of bio-char with sulfuric acid ($H_2SO_4$) and sulfuryl chloride ($SO_2Cl_2$), respectively. The treated catalysts were characterized and their catalytic activities were evaluated by esterification of oleic acid. The esterification catalytic activity of the $SO_2Cl_2$-treated bio-char was higher ($11.5mmol\;Prod.{\cdot}h^{-1}{\cdot}gCat.\;^{-1}$) than that of commercial catalyst silica-supported Nafion SAC-13 ($2.3mmol\;Prod.{\cdot}h^{-1}{\cdot}gCat.^{-1}$) and $H_2SO_4$-treated bio-char ($5.7mmol\;Prod.{\cdot}h^{-1}{\cdot}gCat.^{-1}$). Reusability of the catalysts was examined. The catalytic activity of the $SO_2Cl_2$-modified catalyst was sustained from the second run after the initial activity dropped after the first run and kept the same activity until the fifth run. It was higher than that of first-used Nafion. These experimental results demonstrate that catalysts from lipid-extracted algae have great potential for the economic and environment-friendly production of biodiesel.

• Journal of Microbiology and Biotechnology
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• 제18권12호
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• pp.1919-1926
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• 2008

Statistical experimental designs; involving (i) a fractional factorial design (FFD) and (ii) a central composite design (CCD) were applied to optimize the culture medium constituents for production of a unique antifreeze protein by the Antartic micro algae Chaetoceros neogracile. The results of the FFD suggested that NaCl, KCl, $MgCl_2$, and ${Na}_{2}{SiO}_{3}$ were significant variables that highly influenced the growth rate and biomass production. The optimum culture medium for the production of an antifreeze protein from C. neogracile was found to be Kalle's artificial seawater, pH of $7.0{\pm}0.5$, consisting of 28.566 g/l of NaCl, 3.887 g/l of $MgCl_2$, 1.787 g/l of $MgSO_4$, 1.308 g/l of $CaSO_4$, 0.832 g/l of ${K_2}{SO_4}$, 0.124 g/l of $CaCO_3$, 0.103 g/l of KBr, 0.0288 g/l of $SrSO_4$, and 0.0282 g/l of ${H_3}{BO_3}$. The antifreeze activity significantly increased after cells were treated with cold shock (at $-5^{\circ}C$) for 14 h. To the best of our knowledge, this is the first report demonstrating an antifreeze-like protein of C. neogracile.

• Applied Biological Chemistry
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• 제20권1호
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• pp.123-129
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• 1977

효모세포벽 분해효소를 생산하는 386주(株)의 미생물을 분리하여 그중 강한 1주(株)를 선발 동정(同定)하고 선정균의 효소생산조건을 검토하여 다음과 같은 결과를 얻었다. 1. 선정한 M-10 strain은 Humicola sp.로 동정(同定) 되었다. 2. 선정균의 효소생성은 pH 6.0 $33^{\circ}C$에서 가장 양호하였다. 3. 탄소원으로서 baker's yeast 4%가 Iytic enzyme 생산에 가장좋았고 기타 laminarin과 dextrin 등이 효과적이었으며 질소원도 peptone이 다소 효과적이나 baker's yeast로서 족하였다. 4. 효소생산에 $K_2HPO_4$ 0.1%와 $MgSO_4{\cdot}7H_2O$ 0.01%의 첨가가 가장 효과적이고 기타 염류의 첨가는 효과가 없었다. 5. 선정한 배지조성에서 72시간 진탕배양으로 최고에 달하였다.

• KSBB Journal
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• 제19권5호
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• pp.374-380
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• 2004

Production of therapeutic proteins by transgenic plant cell suspension cultures is an attractive system alternative to the other expression system. However, plant cell cultures have shown low expression level of foreign proteins and decreased cell viability by the changes of culture conditions. Therefore, it is necessary to enhance cell viability during the culture period. In this study, a quantitative analysis technique was designed to measure relative cell viability for plant suspension cells which have cell wall and aggregates. It was found that the programmed cell death of plant cells by apoptosis was essentially linked with the apoptotic pathway of animal cells. Therefore, effects of nicotinamide, 3-aminobenzamide and antioxidants on cell viability and apoptosis were examined in transgenic Nicotiana tabacum cells producing hGM-CSF. With those additives, cell viability could be maintained and apoptosis could be redued. In the result, the extracellular production of hGM-CSF could be enhanced 2.5 fold. It was also found that the supplementation of glutathione and ascorbic acid suppressed both the cold stress-induced decrease in cell viability and the increase of total genomic DNA fragmentation.

• Applied Biological Chemistry
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• 제30권3호
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• pp.258-263
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• 1987

절간고구마 주정폐액은 여과가 용이하고, 유기질 함량이 높으며 pH가 효모의 생육에 적합하여 미생물의 단세포 단백질(single cell protein) 생산을 위한 기질로 적합하였다. 본 실험에 사용한 Candida boidinii는 토양으로부터 분리된 고구마 주정폐액 자화성이 가장 우수한 균주로서, 72시간 배양하였을 때 배지 100ml당 1.02g의 건조균체량을 얻을 수 있었으며, 이 때의 조단백질 함량은 54.5%였다. 효모의 생육은 pH 5.0과 $30^{\circ}C$에서 72시간 배양하였을 때 최대에 달하였고 urea 0.2%와 무기염류를 첨가하면 생육이 촉진되었다.

• KSBB Journal
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• 제23권3호
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• pp.199-204
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• 2008

Culture conditions for biological hydrogen production were investigated in wastewater of Takju manufacturing factory. Rhodobacter spaeroides KCTC1425, photosynthesis bacteria, and Enterobacter cloacae YJ-1, anaerobic bacteria were used. The hydrogen production were $195.3m{\ell}{\cdot}H_2/{\ell}$ broth for Rhodobacter spaeroides KCTC1425 and $271.8m{\ell}{\cdot}H_2/{\ell}$ broth for Enterobacter cloacae YJ-1 during 36 h. The hydrogen production increased with light intensity, and were highest over 12000Lux. In mixed culture of Rhodobacter spaeroides KCTC1425 and Enterobacter cloacae Y J-1, the optimum mixing ratio of hydrogen production was 20 and 80. Adding volume of yeast extract for maximum hydrogen production was 15 $g/{\ell}$, but there was no effect over that. $Na_2MoO_4$ was most effective among the inorganic salts, and the optimum volume was 0.4 $g/{\ell}$. In semi-continuous culture, total hydrogen production was $13086m{\ell}{\cdot}H_2/{\ell}$ broth for 144 h with operating period of 24 h.

• Journal of Microbiology and Biotechnology
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• 제30권12호
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• pp.1876-1884
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• 2020

Ethanol often accumulates during the process of wine fermentation, and mitophagy has critical role in ethanol output. However, the relationship between mitophagy and ethanol stress is still unclear. In this study, the expression of ATG11 and ATG32 genes exposed to ethanol stress was accessed by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). The result indicated that ethanol stress induced expression of the ATG11 and ATG32 genes. The colony sizes and the alcohol yield of atg11 and atg32 were also smaller and lower than those of wild type strain under ethanol whereas the mortality of mutants is higher. Furthermore, compared with wild type, the membrane integrity and the mitochondrial membrane potential of atg11 and atg32 exhibited greater damage following ethanol stress. In addition, a greater proportion of mutant cells were arrested at the G1/G0 cell cycle. There was more aggregation of peroxide hydrogen (H2O2) and superoxide anion (O2•-) in mutants. These changes in H2O2 and O2•- in yeasts were altered by reductants or inhibitors of scavenging enzyme by means of regulating the expression of ATG11 and ATG32 genes. Inhibitors of the mitochondrial electron transport chain (mtETC) also increased production of H2O2 and O2•- by enhancing expression of the ATG11 and ATG32 genes. Further results showed that activator or inhibitor of autophagy also activated or inhibited mitophagy by altering production of H2O2 and O2•. Therefore, ethanol stress induces mitophagy which improves yeast the tolerance to ethanol and the level of mitophagy during ethanol stress is regulated by ROS derived from mtETC.

• 대한약학회:학술대회논문집
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• 대한약학회 2001년도 Proceedings of International Convention of the Pharmaceutical Society of Korea
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• pp.135.1-135.1
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• 2001