• Journal of Applied Biological Chemistry
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• v.58 no.1
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• pp.25-29
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• 2015

The determination of the optimum conditions for the conversion of ergosterol to vitamin $D_2$ in shitake mushrooms (Lentinula edodes) was studied using response surface methodology (RSM). The effects of the three main variables ambient temperature ($20-40^{\circ}C$), exposure time (60-180 min), and irradiation intensity ($0.6-1.8W/m^2$) were investigated. According to the RSM ridge analysis, the optimum conditions were as follows: ambient temperature of $34.2^{\circ}C$, exposure time of 175.6 min, and irradiation intensity of $1.41W/m^2$. Under these optimum conditions, the maximum vitamin $D_2$ content of $117.93{\mu}g/g$ in shitake mushrooms was obtained, which agreed fairly well with the predicted value of $122.60{\mu}g/g$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.1
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• pp.124-131
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• 2000

In this study, pool boiling performance of Turbo/B-type metal-formed tubes was investigated. Tubes with three different cavity gap width(0.04 mm, 0.07 mm, 0.1 mm) were manufactured and tested using R-11, R-123 and R-134a. Tests were conducted at two different saturation temperatures $4.4^{\circ}C$ and $26.7^{\circ}C.$ Heat flux was varied from 10 kW/m2 to 50 kW/m2. It was found that optimum gap width varied for different refrigerants. For low-pressure refrigerants such as R-11 or R-123, optimum gap width was 0.07 mm. For high-pressure refrigerant R-134a, however, the optimum value was 0.1 mm. Compared with the heat transfer performance of the smooth tube, the metal-formed tubes enhanced the heat transfer coefficients significantly - 6.5 times for R-11, 6.0 times for R-123 and 5.0 times for R-134a (at $4.4^{\circ}C$ saturation temperature and 40 kW/m2 heat flux), which are comparable with the performance of foreign products. The heat transfer coefficients of R-134a were larger than those of R-11 or R-123, and they increased as the saturation temperature increased.

• The Research Journal of the Costume Culture
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• v.7 no.2
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• pp.315-322
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• 1999

The acquistion and dyeability of the Gardenia jasminoides were examined to establish the optimum condition for extraction and storage in the process of obtaining the natural dye, Gardenia jasminoides colorant. Also the dyeability and colorfastness of Gardenia jasminoides were investigated. The results of this study are as follows. The optimum part-removed seed. In all experiments, the part of fat-removed seed and pericarp was used. The optimum condition for extraction of Gardenia jasminoides colorant was at 40℃ and for 90 min. in methanol. As storage temperature was higher, the absorbance of colorant extract decreased rapidly. The Gardenia jasminoides colorant exhibited dyeability to cotton, silk, wool, and nylon. The dyeability was the greatest in wool, and then nylon, silk, and cotton. Both wool and nylon had the greatest K/S value at pH3, however, nylon and cotton at pH 6 and pH 8 respectively. In addition, the increase in K/S value corresponded to temperature in wool and nylon, but the silk and cotton had the greatest K/S value at 60℃. Also, the K/S value increased in concomitant with the increased number of dyeing repetition. In the most cases, colorfastness of light was weak but colorfastness of laundry, sweat was relatively excellent.

• Journal of the Korean Ceramic Society
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• v.32 no.4
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• pp.455-461
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• 1995

To investigate the synthesis of $\beta$-Al2O3 and its crystallization behavior by oxalate coprecipitation method, the optimum pH range for oxalate coprecipitates has been theoretically calculated from the solubility products and the equilibrium constans of each metal ionic species and their solubility diagram wa obtained. The optimum pH range for oxalate coprecipitates at room temperature was estimated as <4. In experiment, we found that the optimum condition for oxalate coprecipitates was pH<1, which was not doped with pH controller. The Na+ ions were easily exchanged for the NH4+ ions of NH4OH which was used as pH controller, and those NH4+ ions were supposed to affect the crystallization behavior of $\beta$-Al2O3. The thermal decomposition of all complexes was almost complete below 40$0^{\circ}C$. The primary product of the decomposition process was m-Al2O3, which transformed to $\beta$"- or $\beta$-Al2O3 at temperature higher than 100$0^{\circ}C$. We found that the powder prepared at 120$0^{\circ}C$ had only $\beta$"- and $\beta$-Al2O3.EX>-Al2O3.

• ALGAE
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• v.28 no.1
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• pp.101-109
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• 2013

Some Chlorella species grow heterotrophically with organic substrate in dark condition. However, heterotrophic Chlorella species are limited and their optimum culture conditions are not fully known. In this study, three heterotrophic Chlorella species, two strains (C4-3 and C4-4) of C. vulgaris and one Chlorella sp. (C4-8) were examined on optimum culture conditions such as carbon source, temperature, and concentrations of nitrogen and phosphorus in Jaworski's medium (JM). And the growth and fatty acid composition of Chlorella were analyzed. For three heterotrophic Chlorella species, glucose (1-2%) as a carbon source only increased the growth and the range of optimum culture temperature was $26-28^{\circ}C$. Doubled concentrations of the nitrogen or phosphorus in JM medium also improved the growth of Chlorella. Chlorella cultured heterotrophically showed significantly higher growth rate and bigger cell size than those autotrophically did. C. vulgaris (C4-3) cultured heterotrophically showed the highest biomass in dry weight ($0.8g\;L^{-1}$) among three species. With respect to fatty acid composition, the contents of C16:0 and n-3 highly unsaturated fatty acid (HUFA) were significantly higher in autotrophic Chlorella than in heterotrophic one and those of total lipid were not different between different concentrations of nitrogen and phosphorus in JM medium. Among three Chlorella species in this study, C. vulgaris (C4-3) appeared to be the most ideal heterotrophic Chlorella species for industrial application since it had a high biomass and lipid content.

• Mycobiology
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• v.38 no.3
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• pp.171-175
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• 2010

Metacordyceps yongmunensis is a newly reported species from Korea, which is very similar to Cordyceps species in morphological characters. It grows on large lepidopteran pupa, and numerous white stromata grow on a single host. Mycelial growth characteristics of M. yongmunensis isolates were studied in different media and at different temperatures. Also, different carbon sources, nitrogen sources, and mineral salts were tested for mycelial growth of M. yongmunensis. Schizophyllum (mushroom) genetics complete medium plus yeast extract, Schizophyllum (mushroom) genetics minimal medium, and Martin's peptone dextrose agar produced longer colony diameters and more compact mycelial density than other media. The optimum temperature for mycelial growth was $25^{\circ}C$. Carbon sources such as sucrose, soluble starch, dextrose, glucose, dextrin, maltose, and fructose showed better mycelial growth, whereas peptone, yeast extract and tryptone resulted in the best mycelial growth of all of the nitrogen sources tested. All of the mineral salts tested showed similar growth as the control, except $K_2HPO_4$ which showed longer colony diameter and more compact mycelial density. The compact colonies were white and cottony with a greenish margin. The results showed that M. yongmunensis is an easy fungus to growas it grew from 30 to more than 50 mm in 2 wk.

• Korean Journal of Microbiology
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• v.9 no.4
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• pp.163-168
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• 1971

Neutral protease which was obtained from a genus of Aspergilli as the crystal form were investigated for their purification and properties. The results of biochemical and enzymatic studies for their purification and properties in this enzyme were as follows. 1) On the wheat media containing 70%-water and $CaCo_{3}$, Aspergilus oryzae S.H.W. 131 is satisfactorily grown under the basic optimum conditions temperature $27^{\circ}C$- $30^{\circ}C$at relative humidity 100% for three days. 2) The enzyme solution extracted with water is successively purified through the passing on column of Asmti-177N for decolorization of it. And ion exchanger such as DEAAE Sphadex A-50 or Shepadex G-100 and fraction collector is necessary for the sepearte treatments of this enzyme. After washing it with organic solvents as aceton-EtOH, etc., it should be dried on the vacuum dryer at $40^{\circ}C$) The protease activity is determined by the amounts of amino acids, tyrosine. 4) The optimum pH of neutral protease is 6.0-8.0. 5) In effectively decomposing with this neutral protease, the optimum temperature is $35^{\circ}C$. 6) It is interesting that the amounts of metal ion affects the activity of neutral protease. For examples, if it were treated with manganic ion, its activity would be more effective than any other that.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.3
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• pp.165-169
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• 2008

It has been reported that most wastewater treatment plants have difficulties in nitrogen removal during winter season due to declined activity of nitrifiers in the condition of low temperature. This study was conducted in order to find out optimum operating condition for efficient nitrogen removal in low temperature. A series of operating conditions with various HRTs of each tank were simulated using the GPS-X program. The optimum HRT combination for effective nitrogen removal was 0.3 hr/0.5 hr/1.36 hr/4.84 hr(PreAx/An/Ax/Ox) with 51.4% of T-N removal efficiency and 57.3% of $NH_4^+$-N removal efficiency.

• Advances in Traditional Medicine
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• v.5 no.1
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• pp.43-47
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• 2005

Jack bean urease was immobilized on gelatin beads with the help of glutaraldehyde. The optimum immobilization (67.6%) was obtained at 30mg/ml gelatin concentration, 0.5 mg/bead enzyme protein concentration, 1 % glutaraldehyde and at $4^{\circ}C$ incubation temperature. The $t_{1/2}$ of immobilized urease was approximately 90 days at $4^{\circ}C$ compared with $t_{1/2}$ of 20 days for the soluble urease, under identical condition. The apparent optimum pH shifted from 7.3 to 8.0 when the urease was immobilized. The optimum stability temperature of immobilized urease was found to be $60^{\circ}C$ while that of soluble urease was $45^{\circ}C$. Time-dependent thermal inactivation studies showed monophasic kinetics for soluble urease and immobilized urease at $70^{\circ}C$, respectively. The immobilized urease beads stored at $4^{\circ}C$ showed practically no leaching over a period of 30 days. Here we are presenting an easy and economical way of immobilizing urease on the gelatin beads making it suitable for various applications.

• Journal of Environmental Science International
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• v.18 no.11
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• pp.1261-1270
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• 2009

Fifty hydrocarbon-metabolizing microorganisms were isolated from soil samples polluted by the petroleum oils in Gamman-dong, Busan. Among them, strain 2-3A, showing strong emulsification activity, was selected by oil film-collapsing method. This bacterium was identified as Acinetobacter sp. and designated as Acinetobacter sp. 2-3A. The optimum temperature and pH on the growth of Acinetobacter sp. 2-3A were $25^{\circ}C$ and pH 7.0, respectively. The carbon and nitrogen sources for the most effective emulsification activity were 3.0% olive oil and 0.5% peptone, respectively. The 0.15% potassium phosphate was the most effective emulsification activity as a phosphate source. The optimum emulsification activity condition was $20^{\circ}C$, pH 7.0, and 2.0% NaCl. The optimum time for the best production of biosurfactant was 27 hrs. The emulsification stability was maintained at the temperature range from $4^{\circ}C$ to $100^{\circ}C$, pH range from 6.0 to 10.0, and NaCl range from 0% to 10%. For the oil resolvability of the biosurfactant, the residual oils were investigated by gas chromatography. As a result, it was verified that the biosurfactant decreased and decomposed crude oils from $_nC_{10}$ to $_nC_{32}$.