• Microbiology and Biotechnology Letters
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• 제23권6호
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• pp.723-729
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• 1995

A flocculating sugar tolerant yeast strain was isolated from fermenting Takju. This strain was identified as Saccharomyces cerevisiae CA-1 according to the Lodder's yeast taxonomic studies. The isolated yeast could grow in 50% glucose and in 7% ethanol in the YPD medium. It's optimal growth temperature, initial pH, shaking rate and initial glucose concentration for ethanol fermentation showed 35$\circ$C, 4.5, 150 rpm, 15%, respectively. Ethanol concentration was 63 g/l in 20% glucose after 24 hours, fermentation yield was 0.49 g-ethanol/g-glucose in 10% glucose after 24 hours and ethanol productivity was 3.09 g/l$\cdot $h in 10% glucose after 12 hours in batch fermentation. Repeated batch fermentation was possible for over 50 days and ethanol yield, ethanol productivity and substrate conversion rate were 0.39-0.50 g/g, 1.63-2.08 g/l$\cdot $h and more than 99%, respectively during these periods.

• Journal of the Korea Safety Management & Science
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• 제1권1호
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• pp.259-272
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• 1999

In order to enhance the selectivity, productivity and yield of methyl fructoside, which was synthesized by enzymatic glycosylation of sucrose and methanol solution, controlling of surface property of solid support using different immobilization procedures optimized microenvironment of immobilized invertase. Silanization and polyethylene imine coating methods were adopted to give a hydrophobic and hydrophilic environment of immobilized invertase. As a result, polyethyleneimine coating method gave higher loading of enzyme, effective activity, and relative activity than silanization method, because it brought on increasing the functional density of amino group and enhancing the conservation of activity by regulating of hydrophilicity. And then, hydrophilic environment was possible to restraint the assessing of methyl fructoside molecule, which was more hydrophobic than sucrose, fructose, and glucose molecule in the reaction mixture, into .the active site of immobilizedinvertase. Consequently, hydrophilic microenvironment of immobilized invertase by polyethyleneimine coating obtained higher yield and productivity with increasing conversion than silanized and native invertase. Thus, this procedure optimized the microenvironment of immobilized invertase suitable for the enzymatic synthesis of methyl fructoside.

• Journal of Microbiology and Biotechnology
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• 제23권4호
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• pp.483-488
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• 2013

Ginsenoside Rd was produced from ginsenoside Rc using a thermostable recombinant ${\alpha}-{\small{L}}$-arabinofuranosidase from Caldicellulosiruptor saccharolyticus. The optimal reaction conditions for the production of ginsenoside Rd from Rc were pH 5.5, $80^{\circ}C$, 227 U enzyme/ml, and 8.0 g/l ginsenoside Rc in the presence of 30% (v/v) n-hexane. Under these conditions, the enzyme produced 7.0 g/l ginsenoside Rd after 30 min, with a molar yield of 100% and a productivity of 14 g $l^{-1}\;h^{-1}$. The conversion yield and productivity of ginsenoside Rd are the highest reported thus far among enzymatic transformations.

• Bulletin of the Korean Chemical Society
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• 제30권8호
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• pp.1832-1834
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• 2009

A simple and safe method has been presented for conversion of olefins into bromohydrins using hydrogen bromide and hydrogen peroxide as bromide source by visible light induced within a very short time to get high yield bromohydrins along with a little mount dibromo-product. In this paper, cyclohexene is firstly carried out as the model substrate and investigated the bromination under HBr/$H_2O_2$ system using 150 W incandescent light irradiated in C$Cl_4$ within short time to get good yield of 2-bromocyclohexanol along with a little mount of 1,2-dibromocyclohexane; then, a series of alkenes are brominated to corresponding bromohydrins using the same protocol.

• Journal of the Korean Chemical Society
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• 제60권4호
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• pp.251-256
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• 2016

This paper describes the synthesis of alkali metal salts of urea (ureates) and their application to the direct preparation of 4-nitrosoaniline from nitrobenzene via nucleophilic aromatic substitution of hydrogen. Sodium and potassium ureates were readily prepared from the reaction of urea with sodium hydride, metal methoxides, and metal hydroxides. The effect of ureates as nucleophiles on the conversion of nitrobenzene to 4-nitrosoaniline was investigated and compared with that of a urea-metal hydroxide mixture. It was found that the ureates were superior for producing 4-nitrosoaniline owing to their higher thermal stability of the ureate. The ureate obtained from the treatment of urea with sodium hydride gave the highest yield for the preparation of 4-nitrosoaniline. The ureates generated from the reaction of urea with metal hydroxide also gave high yields of 4-nitrosoaniline. Catalytic hydrogenation of 4-nitrosoaniline afforded polymer-grade 1,4-benzenediamine in quantitative yield.

• Korean Journal of Food Science and Technology
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• 제21권5호
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• pp.662-668
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• 1989

The effect of four different humidities during smokehouse processing on cured color development color intensity, pH, residual nitrite, phenol deposition, TBA value and product yield of Canadian bacon was determined. High humidity resulted in high pigment conversion and lower pH. As the humidity was lowered, more residual nitrite remained, The highest humidity had the highest phenol deposition and TBA value. The lowest humidity had the highest yield.

• Journal of Microbiology
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• 제43권1호
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• pp.38-43
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• 2005

Lactic acid production parameter optimization using Lactobacillus amylovorus NRRL B-4542 was performed using the design of experiments (DOE) available in the form of an orthogonal array and a software for automatic design and analysis of the experiments, both based on Taguchi protocol. Optimal levels of physical parameters and key media components namely temperature, pH, inoculum size, moisture, yeast extract, $MgSO_4{\cdot}7H_20$, Tween 80, and corn steep liquor (CSL) were determined. Among the physical parameters, temperature contributed higher influence, and among media components, yeast extract, $MgSO_4{\cdot}7H_20$, and Tween 80 played important roles in the conversion of starch to lactic acid. The expected yield of lactic acid under these optimal conditions was 95.80% and the actual yield at optimum conditions was 93.50%.

• KSBB Journal
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• 제15권5호
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• pp.458-463
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• 2000

Production of acetic acid from cellulosic biomass by Simultaneous Saccharification and Extractive Fermentation (SSEF) was investigated. The homoacetate organism used in this study was a strain of Clostridium thermoaceticum, ATCC # 49707. A batch operation of Simultaneous Saccharification and Fermentation(SSF) using ${\alpha}$-cellulose at pH 5.5 and 55$^{\circ}C$ yielded 40% conversion of cellulose to acetic acid, while a fed-batch SSF operation produced a maximum acetic acid concentration of 25 g/L, with 50% overall yield. In-situ extractive fermentation to reduce the end-product inhibition on both bacteria and enzyme was carried out. in a batch SSEF using 200 g/L IRA-400 resin, acetic acid concentration reached to 23.9 g/L and acetic acid yield and productivity were observed to be 48% and 0.20 g/L-hr, respectively.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• 제42권5호
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• pp.1-14
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• 2010

Bio-ethanol is a promising alternative energy source for reducing both consumption of crude oil and environmental pollution from renewable resources like lignocellulosic biomass such as wood, forest residuals, agricultural leftovers and urban wastes. Based on current technologies, the cost of ethanol production from lignocellulosic materials is relatively high, and the main challenges are the low yield and high cost of the hydrolysis process. Development of more efficient pretreatment technology (physical, chemical, physico-chemical, and biological pretreatment), integration of several microbiological conversions into fewer reactors, and increasing ethanol production capacity may decrease specific investment for ethanol producing plants. The purpose of pretreatment of lignocellulosic material is to improve the accessible surface area of cellulose for hydrolytic enzymes and enhance the conversion of cellulose to glucose and finally high yield ethanol production which is economic and environmental friendly.

• Proceedings of the Ginseng society Conference
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• 고려인삼학회 2002년도 학술대회지
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• pp.486-490
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• 2002

In different approaches ginsenosides were extracted from Korean ginseng roots by ammonia and for comparison with methanol-water and water. The extracts have been analyzed qualitatively and quantitatively to evaluate yield and selectivity of extractions of ginsenosides. Water supplied the lowest yield. The yields of extracts with liquid ammonia were higher than those with methanol-water. However, this is partly due to the conversion of malonyl ginsenoside to normal ginsenosides by ammonia. It was proved by HPLC that malonyl-ginsenosides $m-Rb_1,\;m-Rb_2,$ m-Rc and m-Rd were converted to the corresponding neutral ginsenosides. Furthermore, ginsenosides from ginseng roots were extracted by alkaline methanol-water $(60\%)$ solutions. Alternatively, the extracts of the methanol-water $(60\%)$ extraction were treated with sodium hydroxide solution. Both methods also convert the malonyl-ginsenosides to neutral ginsenosides.