• Journal of Microbiology and Biotechnology
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• v.22 no.5
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• pp.659-667
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• 2012

2,3-Butanediol (2,3-BDO) is an organic compound with a wide range of industrial applications. Although Escherichia coli is often used for the production of organic compounds, the wild-type E. coli does not contain two essential genes in the 2,3-BDO biosynthesis pathway, and cannot ferment 2,3-BDO. Therefore, a 2,3-BDO biosynthesis mutant strain of Escherichia coli was constructed and cultured. To determine the optimum culture factors for 2,3-BDO production, experiments were conducted under different culture environments ranging from strongly acidic to neutral pH. The extracellular metabolite profiles were obtained using high-performance liquid chromatography (HPLC), and the intracellular metabolite profiles were analyzed by ultra-performance liquid chromatography and quadruple time-of-flight mass spectrometry (UPLC/Q-TOF-MS). Metabolic flux analysis (MFA) was used to integrate these profiles. The metabolite profiles showed that 2,3-BDO production favors an acidic environment (pH 5), whereas cell mass favors a neutral environment. Furthermore, when the pH of the culture fell below 5, both the cell growth and 2,3-BDO production were inhibited.

• Korean Journal of Clinical Pharmacy
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• v.3 no.1
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• pp.31-43
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• 1993

The influence of phenobarbital(PB) pretreatment(75mg/kg/day, Lp. for 4 days) on the hepatic clearance of indocyanine green(ICG) as a model compound of organic anionic drugs was investigated in rats in order to elucidate the relative contributions of change in the hepatic blood flow versus increase in the hepatic intrinsic activity to remove ICG due to PB pretreatment. ICG(1mg/kg) was injected single bolus via femoral or portal vein to the control and the PB-pretreated rats. The initial hepatic uptake clearance$(V_{d.c.}K_{12})$ obtained from plasma concentration-time data was increased by $38.4\% in the PB-pretreated rats, which may be due to the increased hepatic blood flow by PB pretreatment. Using a pharmacokinetic approach, hepatic blood flows were estimated of 67.5ml/min/kg in control rats and 91.9ml/min/kg in PB-pretreated rats. They were in good agreement with other's blood flow estimates observed experimentally. It may be concluded that the $38\%$ increased initial hepatic uptake clearance of ICG was due to the $36\%$ increased hepatic blood flow with phenobarbital, and that the increased hepatic blood flow and the activated hepatic intrinsic clearance with phenobarbital contributed to $49\%\;and\;51\%$ of the increased systemic clearance of ICG, respectively.

• Journal of the Korean Institute of Gas
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• v.7 no.2 s.19
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• pp.7-13
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• 2003

Abstract This paper presents new emission mechanism and emission estimation model in volatile organic compounds(VOCs) emission sources. Also classifies applicable emission reduction techniques and presents new economical evaluation method for each techniques. We ultimately developed VEER(VOCs Emission Estimation and Reduction) software, which is backed by above mentioned model, emission source DB, Chemical properties DB, meteorological DB, and emission factor DB. With VEER, users in enterprise, central government and local self-governing body can get reliable emission results easily, and choose suitable emission reduction techniques.

• Bulletin of the Korean Chemical Society
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• v.15 no.2
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• pp.132-138
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• 1994

Bis(diethylamino)aluminum hydride was utilized in a systematic study of the approximate rates and stoichiometry of the reaction of excess reagent with 55 selected organic compounds containing representative functional groups under standardized conditions (THF, $0^{\circ}C$, reagent to compound=4 : 1) in order to define the characteristics of the reagent for selective reductions. The reducing action of BEAH was also compared with that of the parent aluminum hydride. The reducing action of the reagent is quite similar to that of aluminum hydride, but the reducing power is much weaker. Aldehydes and ketones were readily reduced in 1-3 h to the corresponding alcohols. However, unexpectedly, a ready involvement of the double bond in cinnamaldehyde was realized to afford hydrocinnamyl alcohol. The introduction of diethylamino group to the parent aluminum hydride appears not to be appreciably influential in stereoselectivity on the reduction of cyclic ketones. Both p-benzoquinone and anthraquinone utilized 2 equiv of hydride readily without evolution of hydrogen, proceeded cleanly to the 1,4-reduction products. Carboxylic acids and acid chlorides underwent reduction to alcohols slowly, whereas cyclic anhydrides utilized only 2 equiv of hydride slowly to the corresponding hydroxylacids. Especially, benzoic acid with a limiting amount of hydride was reduced to benzaldehyde in a yield of 80%. Esters and lactones were also readily reduced to alcohols. Epoxides examined all reacted slowly to give the ring-opened products. Primary and tertiary amides utilized 1 equiv of hydride fast and further hydride utilization was quite slow. The examination for possibility of achieving a partial reduction to aldehydes was also performed. Among them, benzamide and N,N-dimethylbenzamide gave ca, 90% yields of benzaldehyde. Both the nitriles examined were also slowly reduced to the amines. Unexpectedly, both aliphatic and aromatic nitro compounds proved to be relatively reactive to the reagent. On the other hand, azo- and azoxybenzenes were quite inert to BEAH. Cyclohexanone oxime liberated 1 equiv of hydrogen and utilized 1 equiv of hydride for reduction, corresponding to N-hydroxycyclohexylamine. Pyridine ring compounds were also slowly attacked. Disulfides were readily reduced with hydrogen evolution to the thiols, and dimethyl sulfoxide and diphenyl sulfone were also rapidly reduced to the sulfides.

• Bulletin of the Korean Chemical Society
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• v.13 no.5
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• pp.531-537
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• 1992

The approximate rates and stoichiometry of the reaction of excess potassium 2-thexyl-1,3,2-dioxaborinane hydride(KTDBNH) with 55 selected compounds containing representative functional groups under standardized conditions (tetrahydrofuran, TEX>$0^{\circ}C$, reagent : compound=4 : 1) was examined in order to define the characteristics of the reagent for selective reductions. Benzyl alcohol and phenol evolve hydrogen immediately. However, primary, secondary and tertiary alcohols evolve hydrogen slowly, and the rate of hydrogen evolution is in order of $1^{\circ}$> $2^{\circ}$> $3^{\circ}$. n-Hexylamine is inert toward the reagent, whereas the thiols examined evolve hydrogen rapidly. Aldehydes and ketones are reduced rapidly and quantitatively to give the corresponding alcohols. Cinnamaldehyde is rapidly reduced to cinnamyl alcohol, and further reduction is slow under these conditions. The reaction with p-benzoquinone dose not show a clean reduction, but anthraquinone is cleanly reduced to 9,10-dihydro-9,10-anthracenediol. Carboxylic acids liberate hydrogen immediately, further reduction is very slow. Cyclic anhydrides slowly consume 2 equiv of hydride, corresponding to reduction to the caboxylic acid and alcohol stages. Acid chlorides, esters, and lactones are rapidly and quantitatively reduced to the corresponding carbinols. Epoxides consume 1 equiv hydride slowly. Primary amides evolve 1 equiv of hydrogen readily, but further reduction is slow. Tertiary amides are also reduced slowly. Both aliphatic and aromatic nitriles consume 1 equiv of hydride rapidly, but further hydride uptake is slow. Analysis of the reaction mixture with 2,4-dinitrophenylhydrazine yields 64% of caproaldehyde and 87% of benzaldehyde, respectively. 1-Nitropropane utilizes 2 equiv of hydride, one for hydrogen evolution and the other for reduction. Other nitrogen compounds examined are also reduced slowly. Cyclohexanone oxime undergoes slow reduction to N-cyclohexylhydroxyamine. Pyridine ring is slowly attacked. Disulfides examined are reduced readily to the correponding thiols with rapid evolution of 1 equiv hydrogen. Dimethyl sulfoxide is reduced slowly to dimethyl sulfide, whereas the reduction of diphenyl sulfone is very slow. Sulfonic acids only liberate hydrogen quantitatively without any reduction. Finally, cyclohexyl tosylate is inert to this reagent. Consequently, potassium 2-thexyl-1,3,2-dioxaborinane hydride, a monoalkyldialkoxyborohydride, shows a unique reducing characteristics. The reducing power of this reagent exists somewhere between trialkylborohydrides and trialkoxyborohydride. Therefore, the reagent should find a useful application in organic synthesis, especially in the field of selective reduction.

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.523-529
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• 2019

In this study, we investigated the pretreatment technologies of volatile organic compounds (VOCs) which is a problem as the semiconductor and display industry develops recently. The conventional concentrator used in the direct combustion system, is easily contaminated by the exhaust gas in the manufacturing process of the display, resulting in the low treatment efficiency of generated VOCs. Physical/Chemical analyses of the exhaust gas showed high boiling point and viscosity in addition to a large amount of molecular weight alcohols and oil components. In this study, we tried to treat degrading materials by using the heat exchanger in a pretreatment facility and some materials degrading the concentrator were condensed more than 90%. In addition, it was also confirmed that an auxiliary device of the grease filter could remove the redispersion polymer oil from the heat exchanger.

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.633-638
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• 2019

Indoor air quality underground facilities are not equipped for the removal of volatile organic compounds (VOCs) and they are usually treated by diffusion methods such as ventilation. In this study, an adsorption filter was prepared using various coating methods such as carbon nano fiber (CNF) and dip coating. As a result, the adsorption performance was improved by 2 to 20 times or more compared to that of using the metal foam support. This is maybe due to the enhancement of pore distribution which was confirmed by SEM. In addition, the adsorption performance was 13.95 mg/g by adding lignin, and also an average adsorption performance of 13.25 mg/g was maintained after washing indicating that a highly durable adsorption filter material was prepared. It can be suggested that the developed adsorption filter material can be a potential solution that can fundamentally control VOCs, not via the concentration reduction of mechanical ventilation in underground facilities.

• Journal of odor and indoor environment
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• v.17 no.4
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• pp.372-380
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• 2018

To abate the problem of odor from restaurants, a hybrid adsorbent consisting of organic and inorganic materials was developed and evaluated using acetaldehyde as a model compound was deveioped and evaluated. Powders of activated carbon, bentonite, and calcium hydroxide were mixed and calcinated to form adsorbent structure. The surface area of the hybrid adsorbent was smaller than that of high-quality activated carbon, but its microscopic image showed that contours and pores were developed on its surface. To determine its adsorption capacity, both batch isotherm and continuous flow column experiments were performed, and these results were compared with those using commercially available activated carbon. The isotherm tests showed that the hybrid adsorbent had a capacity 40 times higher than that of the activated carbon. In addition, the column experiments revealed that breakthrough time of the hybrid adsorbent was 2.5 times longer than that of the activated carbon. These experimental results were fitted to numerical simulations by using a homogeneous surface diffusion model (HSDM); the model estimated that the hybrid adsorbent might be able to remove acetaldehyde at a concentration of 40 ppm for a 5-month period. Since various odor compounds are commonly emitted as a mixture when meat is barbecued, it is necessary to conduct a series of experiments and HSDM simulations under various conditions to obtain design parameters for a full-scale device using the hybrid adsorbent.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.10
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• pp.217-223
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• 2019

The purpose of this study was to measure the indoor air quality of small-scale apartments and then proposed a method to improve the indoor air quality of the small-scale apartments by comparing with the result of indoor air quality in the Clean-Healthy House. In case of formaldehyde, a highly volatile organic compound, the concentrations of indoor measured both in small-scale apartments and the Clean Healthy houses did not exceed- the guideline of Korea. The guideline of Korea for acetaldehyde was not available, so the guidelines of Japan and the World Health Organization were used to measure the concentration of acetaldehyde. The study results demonstrated that three out of seven small-scale apartments investigated exceeded the guideline of Japan; and the preliminary research on the Clean-Health Houses was low at about 30-60% of the guideline of Japan. The result of the VOCs measurement showed that toluene, ethylbenzene, and styrene in some small-scale apartments exceeded the guideline of Korea. However, the Clean-Healthy Houses in the previous studies did not exceed the guideline of Korea with regard to all the pollutants. Therefore, this study suggests the application of the construction standards of the Clean-Healthy house in order to improve the indoor air quality of small-scale apartments. In addition, the current study anticipates that improvement of the indoor air quality in the residential environments should be universally applied, not limited to the type and size of the residence.

• Journal of Environmental Health Sciences
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• v.49 no.2
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• pp.78-88
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• 2023

Background: Exposure to volatile organic compounds (VOCs) can have acute and chronic health effects on human beings in general and in working environments. In particular, VOCs are often emitted in large quantities in industrial settings. In such circumstances, there is a need to improve the indoor air quality at workplaces. Objectives: The purposes of this study were to verify the effectiveness of air cleaning devices in workplaces and provide alternative solutions for improving working environments. Methods: Personal exposure and area level of VOCs for workers were evaluated in a car-part adhesive process before and after installing an air cleaning device with a TiO₂-coated filter. Passive samplers and direct reading instruments were used to collect and analyze the VOCs, and the removal efficiency and improvement of air quality were evaluated. We also calculated the exposure index (EI) to assess the risk level in the workplace. Results: The removal efficiency for VOCs through the installation of the air cleaning device was approximately 26.9~69.0% as determined by the concentration levels before and after installation. The measured substances did not exceed the exposure limits for the work environment and the EI was less than 1. However, carcinogenic substances such as benzene, formaldehyde, carbon tetrachloride, and trichloroethylene were detected. Conclusions: The application of an air cleaning device can be a solution for controlling the indoor air quality in a workplace, particularly in cases where ventilation systems cannot be installed due to process limitations.