• Applied Biological Chemistry
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• v.34 no.4
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• pp.386-392
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• 1991

Whole cells of Methylosinus trichosporium OB3b, the obligate methylotroph, were used to produce propylene oxide from propane. This strain has methane monooxygenase, which catalyzes the conversion methane to methanol and can catalyze also the conversion propane to propylene oxide. Optimal condition for the production of propylene oxide was investigated in resting-whole cell system. The optimal pH and temperature was 7.0 and $35^{\circ}C$ respectively. The end product, propylene oxide, didn't inhibit the production of propylene oxide and was not further metabolized in reaction mixture. The addition of methane metabolites (methanol, formaldehde and formic acid) to the reaction mixture stimulated formation of propylene oxide by $3{\sim}4$ times, and methanol was the most effective especially. Under the optimal conditions, the 14.2 mM of propylene oxide was produced after incubation of 60 min. and the conversion ratio of propane to propylene oxide was approximately 8%.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.1
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• pp.23-30
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• 2021

To examine the optimal temperature, light intensity, and shell-type for shell-living conchocelis production, we tested the shell infiltration of free-living conchocelis fragments under various environmental conditions. Under a combination of various temperatures (10, 15, 20, 25 and 30℃) and light intensities (1, 5, 10, 20, 40, and 80 μmol m-2 s-1), the optimal infiltration conditions of the evaluated three Pyropia species were 20-25℃ and 5-80 μmol m-2 s-1 for P. yezoensis, 20-30℃ and 20-80 μmol m-2 s-1 for P. seriata, and 20-25℃ and 20-80 μmol m-2 s-1 for P. dentata. The infiltration efficiency of free-living conchocelis for different shell types was greater in Korean and Chinese oyster Crassostrea gigas shells than that in scallop Argopecten irradians and clam Meretrix lusoria shells. These results suggest that oyster shells are suitable substrates for shell-living conchocelis production. In conclusion, the present results for optimal infiltration conditions for free-living conchocelis of the three examined Pyropia species will contribute significantly to the production of stable shell-living conchocelis.

• Korean Journal of Food Science and Technology
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• v.23 no.2
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• pp.167-174
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• 1991

Cultural conditions for the biopolymer production by an alkali tolerant Bacillus sp. isolated from soil were investigated and determination of optimal conditions was carried out by response surface method. The maximal production of biopolymer was obtained after cultivation at $30^{\circ}C$ for 36hrs in the mixture of 8% soluble starch, 0.75% yeast extract, 0.1% $NaNO_3$, 0.05% $MgSO_4\;7H_2O$ and 1% $Na_2CO_3$ adjusted to pH 10. Under these conditions, about 44 g/l of biopolymer were produced. From the results of response surface analysis, optimal condition for the production of biopolymer were obtained at stationary point with 15.16 of C/N ratio, $34.62^{\circ}C$ of temperature and 9.50 of pH. On the basis of these conditions, it was estimated that 66.84 g/l of the biopolymer could be produced.

• Resources Recycling
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• v.17 no.5
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• pp.66-75
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• 2008

Using a pinus koraiensis and pinus rigida which are normally being discarded in South Korea, the optimal condition of producing charcoals has been studied to develop activated carbons which can be recycled as a higher value-added product. A study on manufacture of activated carbons from a discarded timber consists of two processes, the production process of charcoals from a discarded timber by low temperature pyrolysis process and the production process of activated carbons from the charcoals by chemical activation reaction. This study deals with the production process of charcoals from a discarded timber by low temperature pyrolysis process. As a results of experiment, it was investigated that charcoals produced through drying at $150^{\circ}C$ for 6hr and pyrolysis process at $500^{\circ}C$ for 1hr had the highest values in physical properties such as iodine number and BET surface area. Furthermore, through observing SEM images, the maximum development of porosity had been founded in this condition. It was confirmed that values of physical properties on using a pinus koraiensis are superior to the ones when using a pinus rigida. When charcoals were produced from a pinus koraiensis in this condition, BET surface area was approx. $640m^2/g$.

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.82-88
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• 1997

To produce biopolymer, Metarrhizium anisopliae (Metschn.) Sorok was cultured in a medium containing glucose 1.0%, sucrose 2.0% , soluble starch 1.0%, yeast extract 0.5%, polypeptone 0.05%, K$_{2}$HPO$_{4}$ 0.1% MgSO$_{4}$ $\CDOT $ 7H$_{2}$O 0.02%. The culture broth was centrifuged and the polymer was harvested by adding methanol to the culture supermatant. When three times of methanol was added, the polymer was coagulated and precipitated. Then it was further purified through successive SK-1B, SA-20P, HP-20 column chromatographies. This polymer was designated as Biopolymer YU-122.C:H ratio of this Biopolmer YU-122 was 1:2 and small amount of N is detected by CHN analyzer. Glucose and glactose are main components of this polymer. Average molecular weight of this biopolymer was 1.7%$\times $10$^{6}$ by Sepharose 4B gel permeation chromatography. Optimal condition for biopolymer production was investigated. When 5% of mannitol was used as a carbon source, and polypepton as a N source, highest productivity of biopolymer was achieved. C/N ratio as nutrient was also a major factor in polymer production and its optimal ratio was 3.

• Microbiology and Biotechnology Letters
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• v.15 no.5
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• pp.340-345
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• 1987

Microorganisms capable of utilizing D-xylose as a sole carbon and energy source were isolated to ferment D-xylose directly to ethanol. Among them, the strain, which showed the best ability to pro-duce ethanol, was selected and was identified as Fusarium sp. The optimal conditions for the pro-duction of ethanol were 8.0 of initial pH, 33$^{\circ}C$ of temperature, and 2% of substrate concentration. Under this optimal condition, the following results were obtained : maximum ethanol concentration, 7.0g/$\ell$; ethanol yield, 0.35g of ethanol per g of D-xylose (68.6% of theoretical); biomass yield, 0.27g of dry biomass per g of D-xylose.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.2
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• pp.155-160
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• 2003

The optimum cultural conditions for production of red pigment from Monascus anka KCTC 6121 on solid culture were studied. The optimal conditions were found that the strain was cultivated on polished rice with 25% initial moisture content, at 3$0^{\circ}C$, 90% humidity for 12 days. It was also found that the maximum red pigment was extracted when the final culture was left in 80% ethanol for 2 days. The light stability of the extracted red pigment was relative stable since the discoloration rate was less than 8% in 30 days under the indirect light.

• YAKHAK HOEJI
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• v.33 no.6
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• pp.365-371
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• 1989

Microbiological conversion of sterols to 17-ketosteroids has been recognized as a source for commercial preparation of steroidal drugs. In order to develop bacterial strains and process with Brevibacterium lipolyticum IAM 1398 capable of converting cholesterol to 1,4-Androstadiene-3,17-dione (ADD) at about 27% yield, we studied on strain improvement, fermentation condition and whole cell immobilization. By using UV and/or NTG as mutagens, a mutant to convert cholesterol to ADD with higher yield than 60% was selected. Better production of ADD was manifested in the case of maltose used as a supplemental carbon source, and yeast extract or soytone as a nitrogen source. Addition of tween 80 (0.05%) as a surfactant beneficial for increasing the productivity. The optimal initial pH of the medium was 6.5 and optimal culture temperature was $30^{\circ}C$. Whole cell immobilization by using carrageenan, agar, alginate and acrylamide was carried out and the activity of conversion was tested. In the case of carrageenan and agar, immobilized cells were active for at least two cycles of fermentation.

• Journal of Environmental Science International
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• v.11 no.3
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• pp.177-182
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• 2002

A biosurfactant-producing microorganism was isolated from activated sludge by enrichment culture when grown on a minimal salt medium containing n-hexadecane as a sole carbon source. This microorganism was identified as Pseudomonas sp. and it was named Pseudomonas sp. EL-G527. It's optimal culture condition is 2% n-hexadecane, 0.2% NH$_4$NO$_3$, 0.3% KH$_2$PO$_4$, 0.3% $K_2$HPO$_4$, 0.02% MgSO$_4$ㆍ7$H_2O$, 0.0025% CaCk$_2$ㆍ6$H_2O$, 0.0015% FeSO$_4$ㆍ7$H_2O$ in 1$\ell$ distilled water and initial pH 7.0. Cultivation was initiated with a 2% inoculum obtained from starter cultures grown in 30 $m\ell$ of the same medium in 250 $m\ell$ flask. They were cultivated at 3$0^{\circ}C$ in reciprocal shaking incubator and the highest biosurfactant production was observed after 4 days.

• Transactions of Materials Processing
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• v.30 no.4
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• pp.179-185
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• 2021

Lithium ion batteries are generally manufactured by laser and etching using aluminum thin sheet. These processes are relatively expensive and have low productivity. In this study, blanking process of aluminum thin sheet for lithium ion battery was employed to replace laser cutting and etching process, all to reduce the production cost and improve productivity. Mechanical properties for aluminum and coating were determined by experimental results and rule of mixture for FE analysis of blanking process. Normalized Cockcroft-Latham criteria was also applied to describe shear behavior and critical damage values were determined by comparison of analytical and experimental result. We performed FE analysis to investigate the effects of clearance and punch-die radius on sheared surface of aluminum thin sheet and to determine optimal process condition. We manufactured the die set using the determined optimal process and conducted an experiment to confirm the feasibility of blanking process. The sheared surface of manufactured product was observed by optical microscope. As a results, the proposed process conditions successfully achieved the dimensional requirement in production of lithium ion battery parts.