• Transactions of the Korean hydrogen and new energy society
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• v.23 no.5
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• pp.559-571
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• 2012

Dimethyl ether (DME) is a new clean fuel as an environmentally-benign energy resource. DME can be manufactured from various energy sources including natural gas, coal, and biomass. In addition to its environmentally friendly properties, DME has similar characteristics to those of LPG. The aim of this article is to represent the development of new DME process with KOGAS's own technologies. KOGAS has investigated and developed new innovative DME synthesis process from synthesis gas in gaseous phase fixed bed reactor. DME has been traditionally produced by the dehydration of methanol which is produced from syngas, a product of natural gas reforming. This traditional process is thus called the two-step method of preparing DME. However, DME can also be manufactured directly from syngas (single-step). The single-step method needs only one reactor for the synthesis of DME, instead of two for the two-step process. It can also alleviate the thermodynamic limitations associated with the synthesis of methanol, by converting the produced methanol into DME, thereby potentially enhancing the overall conversion of syngas into DME. KOGAS had launched the 10 ton/day DME demonstration plant project in 2004 at Incheon KOGAS LNG terminal. In the mid of 2008, KOGAS had finished the construction of this plant and has successively finished the demonstration plant operation. And since 2008, we have established the basic design of commercial plant which can produce 3,000 ton/day DME.

• Advances in nano research
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• v.10 no.2
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• pp.191-210
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• 2021

To compare the antifungal effect of two nanomaterials (NMs), nanoparticles of zinc oxide were synthesized by a chemical route and zinc oxide-based nanobiohybrids were obtained using green synthesis in an extract of garlic (Allium sativum). The techniques of X-Ray Diffraction (XRD), Infrared (IR) and Ultraviolet Visible (UV-Vis) absorption spectroscopies and Scanning (SEM) and Transmission Electron Microscopies (TEM) were used to determine the characteristics of the nanomaterials synthesized. The results showed that the samples obtained were of nanometric size (< 100 nm). To compare their antifungal capacity, their effect on Cercospora sp. was evaluated. Test results showed that both nanomaterials had an antifungal capacity. The nanobiohybrids (green route) gave an inhibition of fungal growth of ~72.4% while with the ZnO-NPs (chemical route), inhibition was ~87.1%. Microstructural studies using High Resolution Optical Microscopy (HROM) and ultra-structural analysis using TEM carried out on the treated strains demonstrated the effect of the nanofungicides on the vegetative and reproductive structures, as well as on their cell wall. To account for the antifungal effect presented by ZnO-NPs and ZnO nanobiohybrids on the fungi tested, effects reported in the literature related to the action of nanomaterials on biological entities were considered. Specifically, we discuss the electrical interaction of the ZnO-NPs with the cell membrane and the biomolecules (proteins) present in the fungi, taking into account the n-type nature of the ZnO semiconductor and the electrical behavior of the fungal cell membrane and that of the proteins that make up the protein crown.

• New & Renewable Energy
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• v.19 no.4
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• pp.35-45
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• 2023

Global efforts are focused on achieving carbon neutrality due to the increases in the levels of greenhouse gases. Moreover, the greenhouse gases generated from the disposal of municipal solid waste (MSW) are the primary sources of emissions in South Korea. In this study, we conducted the biological conversion of syngas (CO, H₂, and CO₂) generated from MSW gasification. The MSW-derived syngas was used as a feed source for cultivating Eubacterium limosum KIST612, and pressurization was employed to enhance gas solubility in culture broth. However, the pH of the medium decreased owing to the pressurization because of the CO₂ in the syngas and the cultivation-associated organic acid production. The replacement of conventional HEPES buffer with a phosphate buffer led to an approximately 2.5-fold increase in acetic acid concentration. Furthermore, compared with the control group, the pressurized reactor exhibited a maximum 8.28-fold increase in the CO consumption rate and a 3.8-fold increase in the H2 consumption rate.

• Applied Biological Chemistry
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• v.26 no.4
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• pp.231-238
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• 1983

N-Benzoylglycylanilide and N-benzoylalanylanilide derivatives were synthesized from N-benzoylglycine and N-benzoylalane with anilines. respectively. The products were identified by elemental analysis, IR, UV and NMR spectra with N-benzoylglycylanilide (I), N-benzoylglycyl-o-toluidide(II), N-benzoylglycyl-m-toluidide(III), N-benzoylglycyl-p-toluidide(IV), N-benzoyl-L-alanylanilide(V), N-bnzoyl-L-alanyl-o-toluidide(VI), N-benzoyl-L-alnnyl-m-toluidise(VII), N-benzoyl-L-alanyl-p-toluidide(VIII). These compounds were tested for their phytotoxicity to the germination and seedling growth of rice, radish, green pea plants and turf grass. Among them, N-benzoyl-Lalanyl-m-toluidide had strongly inhibitory effect on the seedling growth of radish seeds, and N-benzoyl-L-alanylanilide showed an inhibitory activity especially upon the seedling growth of turf seeds. In addition, the inhibitory rate of plant seed growth differed with the isomeric position(ortho, meta and para) of methyl group; N-benzoylglycyl-m-toluidide was more effective than both N-benzoylglycyl-o-toluidide and N-benzoylglycyl-p-toluidide derivatives, and also N-benzoyl-L-alanyl-m-toluidide was more effective than both N-benzoyl-L-alanyl-o-toluidide and N-benzoyl-L-alanyl-p-toluidide.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.1
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• pp.29-36
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• 2014

Dendrobium candidum is one of the well-known orchid on traditional and rare medicinal herb in China. We artificially cultured protocorm-like body and multiple shoots using the bioreactor culture system from Dendrobium candidum and experimented an efficacy as a cosmetic ingredient for skin care. Several studies previously have reported anti-tumor, wound healing and immunological function of Dendrobium candidum but other efficacies were not well known. In the present study, we investigated the cosmetic efficacy to know applicable value of protocorm-like body and multiple shoots cultured from Dendrobium candidum as a cosmetic ingredient. The biological activities of extracts from protocorm-like body, multiple shoots, aerial part and underground part of Dendrobium candidum were investigated. Results were found that extracts of protocorm-like body are superior to other extracts (underground part, aerial part and multiple shoots extracts) on anti-oxidant effect. Also, protocorm-like body extract contained the phenolic and flavonoid compounds more than aerial part, underground part and multiple shoots extracts. In addition, we investigated skin whitening effect related to whitening of skin. In tyrosinase activity and melanin synthesis assay, multiple shoots extract is superior to other extracts (aerial part, underground part and protocorm-like body), on inhibitory effect of tyrosinase activity and melanin synthesis respectively. These results indicate that the protocorm-like body and multiple shoots extracts cultured from Dendrobium candidum presents a new possibility of being applicable to skin improvement as a cosmetic ingredient.

• Applied Chemistry for Engineering
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• v.25 no.4
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• pp.392-395
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• 2014

(2S,3S,4S)-3,4-Dihydroxyglutamic acid (DHGA), a biologically active ${\alpha},{\beta}$-dihydroxy-${\gamma}$-amino acid, was efficiently synthesized from a readily available D-serine derivative in 30% overall yield over 11 steps. The key stereoselective $OsO_4$-catalyzed dihydroxylation reaction controlled by an N-diphenylmethylene group on the amino group of ${\gamma}$-amino-${\alpha},{\beta}$-unsaturated (Z)-ester successfully introduced the diol moiety of the intermediate 5a in 86% with more than 10 : 1 diastereomeric ration. Then it was in turn successfully converted to the desired target compound, (2S,3S,4S)-3,4-DHGA, via simple oxidation and hydrolysis in a highly stereoselective manner and a higher yield than the previous syntheses. This result strongly supports that our synthetic methodology of stereoselective $OsO_4$-catalyzed dihydroxylation should be useful in stereoselctive synthesis of various bioactive compounds with an amino diol moiety.

• Journal of Applied Biological Chemistry
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• v.59 no.1
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• pp.49-56
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• 2016

The current study investigated the anti-obesity effect of Cissus quadrangularsis extracts (CQR-300) and its molecular action mechanism on obese mice induced high-fat diet (HFD). To induce the obesity, mice were fed a HFD for 6 weeks and then fed HFD only or HFD with CQR-300 at 50 and 200 mg/kg. Then, body weight gain and white adipose tissue weights were measured. We investigated the reduction in body fat and the regulation of fatty acid synthesis was measured by dual energy X-ray absorptiometry and real-time PCR with Western blot, respectively. In vitro study, CQR-300 inhibited pancreatic lipase activity. The CQR-300 treatment was significantly decreased the body weight gain and adipocytes size as well as white adipose tissues weights in HFD-induced obese mice. Furthermore, CQR-300 reduced the body fat and fat mass with regulating of adipose tissue hormones as leptin. Treatment with 50 mg/kg CQR-300 showed effectively lower expression levels of adipogenesis/lipogenesis related genes and proteins such as CCAAT/enhancer binding protein ${\alpha}$ ($C/EBP{\alpha}$), peroxisome proliferator-activated receptor ${\gamma}$ ($PPAR{\gamma}$), Sterol regulatory element binding protein-1c (SREBP-1c), and fatty acid synthase (FAS) in white adipose tissue (WAT) as compared with the HFD fed only mice. These results suggest that the CQR-300 has an anti-obesity effect via inhibition of lipase activity, decrease the body fat mass by regulating the adipogenesis and lipogenesis related genes and proteins in epididymal adipose tissue with evaluate body fat reduce in the HFD-induced obese mice.

• Applied Biological Chemistry
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• v.41 no.6
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• pp.471-476
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• 1998

A synthesis and the screening of new 2-iminothiazolines (IV) of which structures are modified based on a lead compound, thiazoline for development of new agrochemical fungicide were described. Bromination of acetoacetanilides (I) which were prepared by the reaction of diketene with anilines gave the corresponding ${\gamma}-bromoacetoactanilide\;(II)$. Treatment of II with N-phenyl-N'-methyl thiourea (III) afforded IV, structure of which was confirmed by various spectroscopic methods. Antifungal activity of the new IV was tested against six kinds of typical plant diseases (in vivo). The IV with aromatic substituents showed remarkable activity against the Pyricuraria oryzae at 250 ppm in primary screening. The candidates with control value over 90% in primary screening were selected and further tested for second screening at lower concentrations. The IV which has an electron-withdrawing substituent such as halogen, especially fluorine in aryl group showed a higher activity as compared to those with electron-donating group and meta substituent was for optimal position.

• Applied Biological Chemistry
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• v.13 no.3
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• pp.197-205
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• 1970

Inositols are cyclohexanehexol and they have been known to be nine stereomers. Scyllo-inositol, epi-inositol and muco-inositol could be synthesized from myo-inositol. Scyllo-inositol and epi-inositol were obtained by oxidation and reduction process from myo-inositol. Myo-inositol and epi-inositol were oxidized by treatment, in solution, with dilute hydrogen peroxide. In all cases, only axial hydroxyl groups were oxidized and monoketons were obtained. Reduction of myo-inosose-2 with sodium boron hydride was carried out in $pH2{\sim}3.$ The reduction products were equatorial alcohol but: reduction of DL-epi-inosose-2 by catalytic reduction produced axial alcohol obtained. Inositol could be esterified. Hexa-O-(p-hydroxy benzoyl)-esters of myo-inositol, scyllo-inositol, epi-inositol and muco-inositol were synthesized and their antimicrobial action on microbes were tested for application to food industry. As the results, it was found that the activities of muco-inositol ester was more vigorous than others.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.352-373
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• 2003

Rhamnose-rich (RROP-s) and fucose-rich (FROP-s) oligo-and polysaccharides were prepared and extensively characterised by physical and chemical procedures [1,2] and compared to L-fucose. Their biological properties were then studied on human skin fibroblast cell cultures, human skin explant cultures and on hairless rat skin, using a variety of cell-biological, biochemical and computerised morphometrical procedures. Among the most important properties we could establish, the following are of particular interest for the tretment and prevention of age-dependent modifications of human skin (loss of skin-tissue, cells and matrix, wrinkle formation and others) : stimulation of cell proliferation (by $^3$[H]-thymidine incorporation and the MTT test), scavenging of reactive oxygen species (ROS) using several different procedures, and protease (MMP-2 and MMP-9) down-regulation. A topical preparation, using RROP-s and FROP-s, and/or L-fucose, was shown to increase cell proliferation, dermal matrix synthesis, efficient scavenging of ROS-s and to increase also the thickness of dermal tissue when applied for 4 weeks on hairless rat skin, accompanied by the densification of collagen bundles as well as by an increase of elastin synthesis. Using fluorescent labeled FROPs, it could be shown that these oligosaccharides react with cell-membrane receptors and especially with the elastin-laminin-receptor and the fucose-mannose receptor, but they penetrate also in the cell nucleus, suggesting the possibility of a direct action on the regulation of gene expression. When applied to the human skin of a team of voluntary women encompassing all age-groups, the efficiency of FROP-containing preparation could be confirmed using indentometry and computerised evaluation of skin micro-relief, as well as evaluation of periorbital wrinkles. It appears therefore that these preparations correspond to all the requirements of active anti-aging principles.