• Clean Technology
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• v.20 no.2
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• pp.108-115
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• 2014

Various metal chlorides and acid catalysts in ionic liquid solvent were investigated to directly convert cellulose into 5-hydroxymethylfurfural (5-HMF). Metal chlorides containing Sn(II), Zn(II), Al(III), Fe(III), Cu(II), and Cr(III) were used and acidic ionic liquid immobilized on silica gel as an acid catalyst and commercial acid catalysts (sulfuric acid, chloric acid, Amberlyst-15,DOWEX50x8) were used for comparison studies. The acid strength and amount of acid catalysts were probed with Hammett indicator. The selectivity and yield of 5-HMF were determined with reaction temperature, reaction time and catalyst ratio. A catalyst containing $CrCl_3-6H_2O$ and $SiO_2-[ASBI]HSO_4$ showed the highest selectivity and it was found that this catalyst had higher activity than commercial solid acid catalysts such as Amberlyst-15 and DOWEX50x8. The selectivity of 5-HMF appeared to be mainly dependent on the acid strength and catalyst ratio, it was found that levulinic acid was produced from 5-HMF by rehydration.

• The Korean Journal of Mycology
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• v.19 no.1
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• pp.79-84
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• 1991

Fruit bodies of Ganoderma lucidum have been used for most pharmacological studies, but pharmacological effects are likely variable because the habitats and strains of Ganoderma lucidum are different. Therefore, their fermentation is required to produce constant and reliable pharmacolo­gical constituents from Ganoderma lucidum. During the studies of medium for industrial application. it was found that ginseng root residues, remaining after being extracted with ethanol, were a good carbon source for a fermentation of Genoderma lucidum and a corn steep liquor was also economical for the nitrogen source. Yield of the mycelial cultured in ginseng root residues and corn steep liquor was 2.5 times higher than that in glucose and peptone, known as a conventional medium of Ganoderma lucidum. The polysaccharide content of the extracts from the cultured mycelia was higher than that from fruit bodies, but protein content was vice versa. Extracts of the cultured mycelia were more effective and lasting than extracts of the fruit bodies in decreased hypertention of spontaneously hypertensive rats (SHR).

• The Korean Journal of Mycology
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• v.44 no.3
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• pp.150-154
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• 2016

To determine a favorable substrate formulation for Grifola frondosa, physicochemical conditions, culture properties, and yields according to various substrate formulations were investigated. Based on these analyses, T4 (80:5:15 ratio of oak sawdust to dried bean-curd refuse to corn husk) resulted in a shorter cultivation period and higher yields (weight of fresh mushrooms harvested at maturity) than those of other treatments. The physicochemical properties of T4 were pH 5.4, 2.4% crude fat contents, 54 C/N ratio, 74.3% porosity, and 0.26 g/cm3 bulk density. These results emphasize the importance of optimal substrate development on the production efficiency of G. frondosa mushrooms and have implications for commercial applications.

• Food Science and Preservation
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• v.24 no.6
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• pp.834-841
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• 2017

This study was carried out to investigate the anti-oxidative and anti-inflammatory effects of hot water extracts of Ligularia fischeri cultivated in Youngyanggun. We obtained hot water extract (HWE) and cold water extract (CWE) from L. fischeri. The anti-oxidative activities of L. fischeri extracts were measured by 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity. The anti-inflammatory effects of L. fischeri were evaluated in human mast cell line-1 (HMC-1) cells stimulated with phorbol-12-myristate-13-acetate plus A23187 (PMACI). The solid yields of HWE was 150% higher than CWE solid yield. Total polyphenol contents of HWE were $198.07{\pm}0.24mg/g$. The value of anti-oxidative activities of HWE were shown $IC_{50}$ $28.2{\pm}0.04ug/mL$. We showed that HWE significantly reduced the PMACI-induced the production of IL-6 (0.01-1 mg/mL), IL-8 (0.1-1 mg/mL), and $TNF-{\alpha}$ (0.01-1 mg/mL). These results indicate that the HWE of L. fischeri can be used as a functional material due to its antioxidant and anti-inflammatory activities.

• KSBB Journal
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• v.10 no.5
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• pp.598-603
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• 1995

Batch and continuous cell retention cultures were carried out using tapioca hydrolysate. In batch culture, reducing sugar of about 180g/$\ell$ was almost consumed in about 36 hours, and the concentration of ethanol produced was about 84g/$\ell$ making the ethanol yield 0.48 g-ethanol/g-(reducing sugar). The final yeast concentration was 8.5${\times}$107 cells/ml(about 2.1g/$\ell$). In a total cell retention culture operated with a dilution rate of 0.18h-1, the yeast concentration, the residual reducing sugar concentration, the ethanol concentration, and the volumetric ethanol productivity were about 40g/$\ell$, about 15g/$\ell$, 81.4g/$\ell$, and 14.7g/$\ell$-h, respectively. In another cell retention culture operated with a dilution rate and a bleed ratio of 0.2h-1 and 0.14, respectively, the yeast concentration increased to 22g/$\ell$ and the ethanol concentration oscillated around 68g/$\ell$. The volumetric ethanol productivity was about 13.6g/$\ell$-h and the residual reducing sugar concentration about 12g/$\ell$ containing glucose of about 4.5g/$\ell$. According to the results of batch fermentation using the solid residue from hydrolysate filtration as the substrate, it seemed to have a certain value. Thus, development of an effective reactor system to produce ethanol from this solid residue is in need.

• Korean Chemical Engineering Research
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• v.51 no.3
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• pp.407-410
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• 2013

The chlorination of a metallurgical-grade silicon was carried out in a fluidized bed reactor, 25 mm in diameter. The flow rate of the chlorine admitted into the reactor was 0.2 L/min and that of the carrier nitrogen was 0.8~1.0 L/min. The reactor temperature was maintained at $450^{\circ}C$ and the temperature of the coolant at the $SiCl_4$ condenser was at $-5^{\circ}C$. The $SiCl_4$ yield increased with increasing the mole fraction of chlorine in the feed gas, exhibiting 28% at the mole fraction of 0.2. Further increase of the chlorine mole fraction was not attempted in a worry that the reactor might be failed due to the high exothermicity of the reaction. The production of $SiCl_4$ from silicon by fluidized bed chlorination was demonstrated on a laboratory scale, which is a stepping stone for future studies under more severe conditions toward industrial application.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.66-72
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• 2018

Corn stover is known as a good candidate for a functional food ingredient when the main lignocellulosic material, lignin, is used as bioactive materials as form of polyphenolic compounds. The purpose of this study was to determine the microwave extraction conditions under which total phenolic compounds (TPC) and flavonoid contents of corn stover were maximized. Microwave-assisted extracts using sulfuric acid ranging from 0 to 1.0 mol with extraction time between 40 and 240 sec were conducted by using response surface methodology (RSM). Microwave power showed significant effects (p<0.05) and the concentrations of TPC and flavonoids increased with increased level of microwave power and extraction time. The optimum conditions for corn stover extraction were determined as 698.6 W, 240 sec, and 0 mol sulfuric acid, and the predicted value of TPC and flavonoid is 82.4 mg GAE/g DM and 18.1 mg/g DM, respectively. Microwave extraction was evaluated as an economic process with low energy consumption, short extraction and high extraction yield of bioactive including TPC and flavonoids compared to conventional extractions.

• Microbiology and Biotechnology Letters
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• v.32 no.2
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• pp.184-189
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• 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
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• v.17 no.5
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• pp.721-727
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• 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.

• Economic and Environmental Geology
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• v.24 no.3
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• pp.319-327
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• 1991

Cheju is the biggest island in Korean peninsula, consisted entirely of volcanic rocks and pyroclastic sediments. The topography is characterized by wide basalt plain in the low altitude but at the center of island, basalt volcano rises 1,950m above sea-level. Surface drainage is very poor, therefore water supply has been dependent on ground water and natural springs. There are about 1,650 production wells and most of them yield $1,000{\sim}2,000mm^3/day$. According to increase of ground water use, saline water is intruded in the low altitude of coastal area. Specially in the eastern coastal area, the topography is extensively flat and the level of ground water is very close to sea-level, at which overuse of ground water has brought saline intrusion up to maximum 6km far from the coast. Hydrochemical monitoring on this salt water intrusion is now undertaken on long term base.