• Transactions of the Korean hydrogen and new energy society
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• v.16 no.4
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• pp.356-363
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• 2005

The purpose of this paper is to investigate the optimal condition of the Syngas production by reforming of fuel using plasmatron. Plasma was generated by air and arc discharge. The effects of applied steam, $CO_2$ or Ni-catalyst on fuel conversion, as well as hydrogen yield and $H_2$/CO ratio were studied. When the variations of $O_2$/fuel ratio, $H_2O$/fuel flow ratio and $CO_2$/fuel flow ratio were $0.94{\sim}1.48$, $4.3{\sim}10$ and $0.8{\sim}3.05$, respectively. Under the condition mentioned above, result of $H_2O$/fuel flow ratio was maximum $H_2$ concentration, or $28.2{\sim}31.6%$, and result of $H_2O$/fuel flow ratio with catalyst was minimum CO concentration or $6.6{\sim}7.1%$. and $H_2$/CO ratio were $3.89{\sim}4.86$.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.253-253
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• 2010

Rice straw was pretreated with aqueous ammonia in order to enhance enzyme digestibility. Soaking in ammonia aqueous (SAA) was conducted with 15% ammonia, at $60^{\circ}C$. for 24 h. Optimization of both saccharification conditions and enzyme loading of SAA rice straw was carried out. Especially enzyme loading test was performed using statistical method. Moreover proton beam irradiation (PBI) was also performed to overcome the problem which inhibit the enzyme digestibility at 1-25 kGy doses with 45 MeV of beam energy. Optimal condition for enzymatic saccharification was follows; pH 4.8, $50^{\circ}C$, 60 FPU of enzyme activity, 1:4 ratio of celluase and ${\beta}$-glucosidase. Also, optimal doses of PBI on rice straw and SAA-treated rice straw for efficient sugar recovery were found to be 3 kGy, respectively. When saccharification was performed with optimal condition, glucose conversion yield was 89% of theocratical maximum in 48 h, and 3 kGy of PBI was applied to SAA-treated rice straw, approximately 90% of the theoretical glucose yield was obtained in 12 h. The results of X-ray diffractometry (XRD) support the effect of both SAA and PBI on sugar recovery, and scanning electron microscopy (SEM) images unveiled the physical change of the rice straw surface since rugged rice straw surface was observed.

• Journal of Plant Biology
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• v.39 no.4
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• pp.309-314
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• 1996

Developmental of photosynthetic pigments and changes in chlorophyll fluorescence of dark-grown rice seedlings were studied during greening. Light-illumination stimulated accumulations of total chlorophylls and carotenoids in leaves of etiolated seedlings, accompanied by a decrease in the ratio of chlorophyll a to chlorophyll b. When the composition of carotenoids was analyzed, violaxanthin level was shown to increase up to 24 h after the beginning of light illumination, followed by a subsequent decline. In contrast to this, zeaxanthin level increased consistently with progress of deetiolatin. The role of zeaxanthin is discussed in relation to chlorophyll fluorescence quenching. A study on chlorophyll fluorescence kinetics of the rice seedlings being deetiolated showed a time-dependent increase in Fv/Fm (yield of variable fluorescence/maximum yield of fluoresecnece) ratios, indicating that greening is responsible for the activation of photochemical reaction centers of the photosystem. When chlorophyll fluorescence quenching was examined, qNP (nonphotochemical quenching) and qE (energy-dependent quenching) exhibited a time-dependent decline with progress of greening. The presented results indicate that greening-induced development of the photosynthetic machinery is associated the conversion of the carotenoid violaxanthin to zeaxanthin, suggesting that zeaxanthin synthesized in the illuminated leaves may provide the protection from the damage when etiolated plants are exposed to light.

• Journal of Life Science
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• v.16 no.1
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• pp.1-5
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• 2006

This study investigated the optimal conditions of high yield production of cyclofructan (CF) using recombinant deletion mutant enzyme CFT108 which is constructed by N-terminal deletion from cycloinulooligosaccharide fructanotransferase (CFTase) gene of Penibacillus polymyxa. The production yield was dependent on reaction time, substrate concentration and enzyme concentration. The optimum reaction time for industrial purpose was achieved at 3 hr reaction. The optimal concentrations of substrate and enzyme were found to be $2\%$ inulin and 40 unit/ g inulin, respectively. At optimum condition, 9.5 g/l of maximum yield and $47.5\%$ of conversion efficacy were achieved. For purification of CF produced, the reaction mixture was treated with 1 unit/ml exoinulinase and then added $3\%$ CaO three times with blowing $CO_2$ gas, resulted in $95\%$ purity.

• KSBB Journal
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• v.13 no.5
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• pp.524-529
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• 1998

An agarase was partially purified from the culture broth of marine bacterium Bacillus cereus ASK202. Optimal pH and temperature of this agarase were found to be 7.0 and 40$^{\circ}C$, respectively. The maximum productivity of agarooligosaccharides was obtained from 0.3 %(w/v) agar by using of 1 unit agarase. As the results of TLC and HPLC analysis, these oilgosaccharides consisted of neoagarobiose, neoagarotetraose and neoagarohexaose. Under the optimal reaction conditions, 77.5 %(w/v) neoagarobiose and 6.2 %(w/v) neoagarotetraose were produced from agar and the conversion yield of total agarooligosaccharides was 83.7 %(w/v) after for 2 h reaction at 40$^{\circ}C$.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.514-518
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• 2008

After overproduction of a recombinant $\beta$-galactosidase of Bifidobacterium infantis in Pichia pastoris, a synthesis of galacto-oligosaccharides (GOS) from 36% lactose using the enzyme (170.74 U/mg) was investigated. The transgalactosylation ratio reached up to 25.2% with 83.1% conversion of initial lactose and the maximum yield of GOS was 40.6%. The GOS syrup was composed of a 13.43% galacto-oligosaccharides, 5.06% lactose, and 8.76% monosaccharides. The prebiotic effect of GOS on the growth of bifidobacteria and lactobacilli strains was investigated in vitro. The maximum growth rate of Bifidobacterium breve and Lactobacillus acidophillus in GOS syrup (5%, v/v) media were 0.49 and 0.96/hr that are higher than those in 1%(w/v) galactose and 1%(w/v) lactose containing media. However, there was no significant difference between the specific growth rates of L. acidophillus in 1%(w/v) glucose and 5%(v/v) GOS syrup. Our data showed that GOS definitely promoted the growth of B. breve ATCC $15700^T$ and L. acidophilus ATCC 33323.

• Microbiology and Biotechnology Letters
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• v.21 no.5
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• pp.494-503
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• 1993

A fungal strain was isolated as a pullulan-producer from plant leaves and identified as Aureobasidium pullulan GM21. With A. pullulans GM21, culture conditions were optimized for the pullulan production and the changes of the molecular weight of pullulan produced were investigated according to the culture conditions we obtained maximum conversion yield of pullulan about 58-60%(40.8-42.0g/l) from 7% sucrose at 25C, initial pH 7.5 by the batch cultivations either in Erlenmeyer flask or in jar fermentor.

• Applied Chemistry for Engineering
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• v.23 no.2
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• pp.164-168
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• 2012

We investigated for the production of biological bio-ethanol from Laminaria japonica using the hydrolysis reaction of enzymes and organic acids and the polysaccharide content was also analyzed. The composition of the polysaccharide was characterized as 65.99% alginate, 6.24% laminaran and 27.77% mannitol. The optimum concentration for reducing the sugar conversion by Laminaria japonica was found to be 1.874 g/L at an acetic acid concentration of 1.5%, $121^{\circ}C$ for 60 min, and for an ascorbic acid of 2.0%, 4.291 g/L was produced in the same condition. The enzyme hydrolysis such as alginate lyase and laminarinase contained the maximum 2.219 g/L reducing sugar. In the result of ethanol fermentation using hydrolysate of Laminaria japonica, the organic acid treatment showed a high of reducing sugar yield, but decreased the ethanol yield, and then the maximum ethanol production obtained was 1.26 g/L using the mixed treated of enzyme.

• Applied Chemistry for Engineering
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• v.5 no.1
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• pp.139-148
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• 1994

The partial oxidation of methane with nitrous oxide on silica-supported metal-oxygen cluster compounds, known as heteropoly acids, has been studied. The effects of several variables such as reaction temperature, partial pressure of reactants, residence time, loading of the catalysts, and pretreatment temperature, on the conversion and product distribution were observed. The kinetics also has been studied. The conversion and yield of formaledehyde show maximum values at a loading of 20 wt%. The apparent reaction order of methane conversion is ca. 1.0 with respect to $CH_4$ and ca. 0.4 with respect to $N_2O$. In addition, the apparent activation energy is 30.78 kcal/mole. The addition of small quantities methane whereas water introduced to the reactant decreased the activity of catalyst under present study.

• Journal of Life Science
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• v.21 no.1
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• pp.127-133
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• 2011

${\beta}$-Galactosidase was immobilized on chitosan bead by covalent bonding using glutaraldehyde. The characteristics of the immobilized enzyme were investigated. Maximum immobilization yield of 75% was obtained on chitosan bead. Optimum pH and temperature for the immobilized enzyme was 7.0 and $50^{\circ}C$, respectively. The immobilized enzyme showed a broader range of pH and temperature compared to a free one. A mathematical model for the operation of the immobilized enzyme in a packed-bed reactor was established and solved numerically. Under different inlet lactose concentrations and feed flow rate conditions, lactose conversion was measured in a packed-bed reactor. The experimental results of continuous operation in a packed-bed reactor were compared to theoretic results using Michaelis-Menten kinetics with competitive product inhibition and external mass transfer resistance. The model predicted the experimental data with errors less than 5%. Process optimization of continuous operation in a packed-bed reactor was also conducted. In a recirculation packed-bed operation, conversion of lactose was 97% in 3 hours. In a continuous packed-bed operation, the effect of flow rate and initial lactose concentration was investigated. Increasing flow rates and initial lactose concentration decreased the conversion of substrate.