• Microbiology and Biotechnology Letters
• /
• v.32 no.2
• /
• pp.184-189
• /
• 2004

Rice wine cake (RWC) is the solid waste obtained after rice wine fermentation. For the mass production of the spores of yeast Saccharomyces from RWC, the optimum pretreatment condition of RWC, the optimum composition of culture medium, and the optimum culture condition were examined. For sporulation, yeast cells were grown in the pre sporulation medium (PSM), transferred into sporulation medium (SM) containing 1 % potassium acetate, and incubated in a rotary shaking incubator at $25^{\circ}C$ for 4 days. The supernatant of the mixture of RWC and water was used as the presporulation medium (PSM). The optimum temperature and time for the pre-incubation of the mixture of RWC and water (1:2) to obtain maximum sporulation yield were $V^{\circ}C$ and 24 hr, respectively, and optimum culture time in PSM was 48 hr. Using these optimum conditions, the asci number obtained was 0.72$ 1.06${\times}$10^{8}$$m\ell$. The addition of wheat coat koji into SM increased the final number of asci to beTEX>$10^{8}$ $m\ell$. Spores were formed in the SM with the initial pH of 7-11, but no spores were formed in the SM with the initial pH of 5. To save the time and effort to pretreat the RWC, 2% and 0.5% RWC without any pretreatment were directly added into PSM containing 1 % brown sugar and SM, respectively, and the maximum asci number of $1.27${\times}$10^{8}$ /$m\ell$ was obtained.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.5
• /
• pp.721-727
• /
• 2007

Stability-enhanced mutants, H44, 11-94, 5A2-84, and F8, of L-threonine aldolase(L-TA) from Streptomyces coelicolor A3(2)(SCO1085) were isolated by an error-prone PCR followed by a high-throughput screening. Each of these mutant, had a single amino acid substitution: H177Y in the H44 mutant, A169T in the 11-94 mutant, D104N in the 5A2-84 mutant and F18I in the F8 mutant. The residual L-TA activity of the wild-type L-TA after a heat treatment for 20 min at $60^{\circ}C$ was only 10.6%. However, those in the stability-enhanced mutants were 85.7% for the H44 mutant, 58.6% for the F8 mutant, 62.1% for the 5A2-84 mutant, and 67.6% for the 11-94 mutant. Although the half-life of the wild-type L-TA at $63^{\circ}C$ was 1.3 min, those of the mutant L-TAs were longer: 14.6 min for the H44 mutant, 3.7 min for the 11-94 mutant, 5.8 min for the 5A2-84 mutant, and 5.0 min for the F8 mutant. The specific activity did not change in most of the mutants, but it was decreased by 45% in the case of mutant F8. When the aldol condensation of glycine and 3,4-dihydroxybenzaldehyde was studied by using whole cells of Escherichia coli containing the wild-type L-TA gene, L-threo-3,4-dihydroxyphenylserine(L-threo-DOPS) was successfully synthesized with a yield of 2.0 mg/ml after 20 repeated batch reactions for 100 h. However, the L-threo-DOPS synthesizing activity of the enzyme decreased with increased cycles of the batch reactions. Compared with the wild-type L-TA, H44 L-TA kept its L-threo-DOPS synthesizing activity almost constant during the 20 repeated batch reactions for 100 h, yielding 4.0 mg/ml of L-threo-DOPS. This result showed that H44 L-TA is more effective than the wild-type L-TA for the mass production of L-threo-DOPS.

• Microbiology and Biotechnology Letters
• /
• v.40 no.3
• /
• pp.208-214
• /
• 2012

Chaff-vinegar is known for having a variety of useful purposes in the fields of health and lifestyles. In a previous study we isolated and identified the active fractions of the polyphenol compound 7 species as a potential biomaterial for cosmeceuticals. To further test for its potential use as a functional material, we carried out an MTT assay, collagenase inhibition assay, elastase inhibition assay, tyrosinase inhibition assay, DPPH free radical scavenging assay, SOD-like activity assay and a xanthine oxidase inhibition assay. Chaff-vinegar exhibited potent collagenase and elastase inhibitory activities in a concentration dependent manner, indicating that the agent has the potential to alleviate the skin wrinkling process. Chaff-vinegar also showed 80% tyrosinase inhibition at a concentration of $100{\mu}L/mL$. DPPH radical scavenging, xanthine oxidase inhibition, and SOD-like activity results for each activity were 80%, 80%, and 100%, respectively. Taken together, the present study suggests that chaff-vinegar is a good candidate for use as an anti-wrinkling and/or whitening agent.

• Archives of design research
• /
• v.19 no.2 s.64
• /
• pp.283-292
• /
• 2006

The Plastic material had been developed in the middle of the 19th century as an alternative material. Along with the development of the electrical engineering industry, it cropped up into center stage as an effective material and has increasingly expanded its use. As such, the plastic material has bound deep-seated ties with the design activities of industrial products, coming into the main material for a variety of industrial designs. Despite its dose affinity to design function in terms of its materialistic property, we have rarely seen examples of intensive study on the realtionship between plastics and designs. This study aims to find the importance that the substance affects industrial products in designs along with the development of plastic materials. With the objective in mind, we made a review of the streamline stylishness that had flourished in the twenties and thirties of the 19th century. Through this study, we understand that the plastic material has a close realtionshop with design activities in three different aspects. First, its amorphous state of nature makes it possible to change into any shape one desires in plastic surgery, which feature in turn influences the moulding of any design forms. Second, the plastic material is best suited to mass-manufacture, which induces to reduce the cost of production. Hence, the expansion of design industry. Third, the plastic material allows the multiple variety of colors, sensitivity, gloss and patterns and infinitely large possibility ranging from natural senses to human senses with the result that numberless diversity of designs cdould come into being.

• Korean Journal of Animal Reproduction
• /
• v.20 no.3
• /
• pp.279-288
• /
• 1996

The objective of this study was to determine the effect of EGF on the development of IVM/IVF bovine embryos and their ICM and TE cell number. In addition, we examined the combined effect of EGF and coculture to the bovine embryo development and the expression of EGF-R protein on bovine embryos by indirect immunofluorescence. The results obtained in these experiments were summarized as follows: When the IVM/IVF 4- to 8-cell embryos were treated at 0, 1, 10, 100 ng/ml of EGF, EGF treatment group showed improved development to blastocyst and increased pattern of ICM and TE cell number compared with control, although there is not significantly different. The stimulating effect of EGF (10 ng/ml) to the develop ment level of IVM/IVF bovine embryos significantly increased development rate to blastocyst after 8-cell stage (p<0.05), although there is no significant effect to the increase of ICM and TE cell numbers. Also, expression of EGF-R on the bovine embryonic stage by indirect immunofluor escence presents after 4-cell stage and the intensity of the EGF-R staining was variable with the development progression. On the other hand, embryos cultured in coculture group added either with or without EGF commonly indicated the significant difference in development rate to blastocyst and Total cell number compared with control. These results suggest that the a addition of EGF to the coculture may stimulate the coculture effect between IVM/IVF bovineembryos and cumulus cells. Therefore, EGF could promote preimplantation bovine embryo development by binding with expressed EGF~R after 4-cell stage, and stimulate the production of embryotrophic factors from the coculture environment. Also, the present study showed that there was no significant effect of EGF to the increase of ICM and TE cell number although the rate of blastocyst significantly increased when treated with EGF after 8-cell stage (p<0.05).

• Reproductive and Developmental Biology
• /
• v.28 no.1
• /
• pp.29-36
• /
• 2004

The objective of this study was to investigate the effects of amino acid supplementation of oocyte maturation medium on 1st polar body(PB) extrusion, embryo development and blastocsyt cell number. In experiment 1, Cumulus oocyte complexes(COCs) were matured in in vitro maturation(IVM) medium supplemented with 1, 2, or 4-fold of 10 $\mu$l/ml MEM non-essential amino acid(NEAA) and 20 Park, $\mu$ l/ml BME essential amino acid(EAA). The PB extrusion rate of oocytes matured in 1-fold amino acid group was significantly higher than that matured in medium without amino acid (p＜0.05), but it was decreased by the increase of the dosage of amino acid. There were no difference in the percentage of embryos reaching 2-cell, 8-cell and blastocyst in all treatments. The number of trophectoderm(TE) cells and total cell number of blastocysts were highest in 2-fold amino acid group, and the number of inner cell mass(ICM) cells was increased by the increase of the dosage of amino acid. In experiment 2, COCs were matured in IVM medium with 1, 5, or 10 mg/ml lactalbumin hydrolysate(LAH). The PB extrusion rate of oocytes matured in medium with 5 mg LAH was significantly higher than that matured in medium with 1 mg LAH (p＜0.05). The development rate to the blastocyst stage was significantly higher in non-supplement and 1 mg LAH group than in 5 mg and 10 mg LAH group (p＜0.05). The number of TE cells and total cell number did not differ among treatment groups, but the number of ICM cells was increased by the increase of LAH supplement. These results suggested that the supplement of certain group of amino acid in IVM medium effective on the quality of blastocyst, and further studies will be accompany with the search of new sources of amino acid used for the use of in vitro embryo production.

• Journal of Animal Science and Technology
• /
• v.46 no.5
• /
• pp.763-772
• /
• 2004

The patterns of fungal growth and fiber digestion under the microscope, and tile productions of fibrolytic enzyme were studied in an in vitro culture with Neocallimastix frontalis SA when either filter paper or rice straw was provided as sole energy source. Under the microscopic observation, active zoospores attachment, sporangium development and complex rhizoidal system were founded on the surface and at the edge of filter paper. After 7 days of incubation, a reduced fiber mass, a decreased fiber cohesion and a weakened fiber structure by fungal digestion were clearly observed. Similar fungal development was observed with rice straw, but fungal growth and digestion took place mostly on the damaged and exposed portion of rice straw. Although there were some differences in absolute concentration and pattern, the concentration of both cellulase and xylanase increased with incubation time with the higher activity being obtained with filter paper. Their differences were large especially after 48 and 96hr of incubation(P< 0.05). The filter paper was more good inducer of cellulolytic and xylanolytic enzymes compared with complex substrate, rice straw. These findings suggest that the filter paper is the better energy source for N frontalis than the complex substrate, and structural disintegration by physical process is able to help rumen fungal growth on the lignified roughage although anaerobic rumen fungi have mechanical and enzymatic functions for fiber digestion.

• Journal of Bio-Environment Control
• /
• v.9 no.2
• /
• pp.115-119
• /
• 2000

Oak mushroom(Lentinus edoes(Berk) Sing) is one of the most important edible mushrooms, and its production has been rapidly increased due to nutritional and medicinal effects. In this study, climatic factors during the growing period of high-quality oak mushroom were analyzed and environmental factors affecting the quality of oak mushroom were discussed. Three places(Changheung, Puyo and Wonj) as mass producing areas of high-quality oak mushrooms and the 15 days of the growing period in 1997-1998 were selected. Major climatic factors for analysis were average air temperature, average relative humidity, ranges of daily air temperature, relative humidity, and wind speed. During the period, th daily average air temperature was $7~20^{\circ}C$ with the diurnal air temperature($7~20^{\circ}C$) and nocturnal air temperature($0~-2^{\circ}C$). The relative humidity ranged between 50 and 70% with the range of daily relative humidity(40~60%). Wind velocity was 1~4m.$s^{-1}$, From the results, it is concluded that the growing environmental conditions for high-quality oak mushroom differed from the optimum conditions for the high productivity of oak mushroom; environmental conditions such as wide ranges of air temperature and relative humidity, low humidity and wind speed might affect the emergence of high-quality oak mushroom.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.5
• /
• pp.26-35
• /
• 2016

As a potential clean energy resource, the production and consumption of hydrogen gas are expected to gradually increase, so that hydrogen related studies are also increasing. The thermal and chemical properties of hydrogen result in its high flammability; in particular, there is a high risk if leaks occur within an enclosed space. In this study, we applied the computational fluid dynamics method to conduct a numerical study on the leakage behavior of hydrogen gas and compared these numerical study results with an experimental study. The leakage hole diameter was selected as an important parameter and the hydrogen gas dispersion behavior in an enclosed space was investigated through various analytical methods. Moreover, the flammable regions were investigated as a function of the leakage time and leakage hole size. We found that the growth rate of the flammable region increases rapidly with increasing leakage hole size. We also investigated the relation between the mass flow rate and the critical time when the hydrogen gas reaches the ceiling. The analysis of the monitoring points showed that the hydrogen gas dispersion behavior is isotropic and independent of the geometry. We found that the concentration of gas in an enclosed space is affected by both the leakage flow rate and amount of gas accumulated in the enclosure.

• Resources Recycling
• /
• v.18 no.2
• /
• pp.39-50
• /
• 2009

Portland cement production is under critical review due to high amount of $CO_2$ gas released to the atmosphere. Attempts to increase the utilization of fly ash, a by-products from thermal power plant to partially replace the cement in concrete are gathering momentum. But most of fly ash is currently dumped in landfills, thus creating a threat to the environment. Many researches on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. Instead, the source of material such as fly ash, that are rich in Silicon(Si) and Aluminium(Al), are activated by alkaline liquids to produce the binder. Hence concrete with no cement is effective in the reduction of $CO_2$ gas. In this study, we investigated the influence of the compressive strength of mortar on alkaline activator and curing condition in order to develop cementless fly ash based alkali-activated concrete. In view of the results, we found out that it was possible for us to make alkali-activated mortar with 70MPa at the age of 28days by using alkaline activator manufactured as 1:1 the mass ratio of 9M NaOH and sodium silicate and applying the atmospheric curing after high temperature at $60^{\circ}C$ for 48hours.