• Korean Journal of Microbiology
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• v.34 no.4
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• pp.219-224
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• 1998

The cyclic metabolism of poly(3-hydroxyhutyrate-co-3-hydroxyvalerate) synthesized from glucose by Alcaligenes sp. SH-69 in the presence or absence of new carbon substrate was investigated. In batch culture, the content and weight average molecular weight of the copolymer already stored in the cell decreased rapidly when there was no other carbon source available. After the depletion of carbon source, the amount of high molecular weight copolymer decreased more rapidly than that of low molecular weight copolymer, and as a result, average molecular weight distribution shifted to the lower value. The addition of a mixture of glucose and levulinic acid when the initial carbon substrate, glucose, was nearly depleted supported the continual increase in cell mass and the accumulation of poly(3HB-co-3HV) with high molar fraction of 3HV. However, solvent fractionation of the polymer with acetone revealed the degradation of pre-existing polyhydroxyalkanoale (PHA) in parallel with the synthesis of PHA from new carbon substrate. Even though PHAs obtained from each substrate alone were the copolymer of 3HB and 3HV, it was found that the polymer accumulated in the cells grown by sequential feeding was mainly physical mixture of two poly(3HB-co-3HV) copolymers containing different molar fractions of 3HV.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.251-254
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• 2000

Effect of carbon sources including agro-industrial byproduct on cell growth and production of curdlan by Agrobacterium sp. ATCC 31749 was investigated. Maximal production of curdlan was obtained when the carbon source was sucrose. The conversion rate of curdlan from 2% (w/v) sucrose was 59%. Glucose, mannose and maltose were also found to be good carbon sources for production of curdlan. Production of curdlan increased up to 3% (w/v) glucose as the carbon source and then decrease as the concentration of glucose increased. The major components of agro-industrial byproduct (AIB) were glucose, maltose, and maltose, and maltotriose. Agrobacterium sp.ATCC 31749 utilized up to 25% (v/v) AIB and produced curdlan with 29.8g/1.

• Journal of the Korean Chemical Society
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• v.20 no.6
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• pp.507-513
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• 1976

Conformation of cis-2-butenedialdioxime, a newly synthesized compound, was assigned by means of nuclearmagnetic resonance, extended Huckel molecular orbital method, and Pople's model of anisotropic effect. It was confirmed that two carbon-carbon single bonds are conrotatorily twisted from the molecular plane of six $sp^2$ orbitals of carbon-carbon double bond. The conformation of minimum energy is found to be twisted by$25^{\circ}C.$

• KSBB Journal
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• v.25 no.3
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• pp.230-238
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• 2010

A microbial strain having high keratinase activity was isolated from the soil of poultry factories of Gyeonggi or Chungcheong-do. The isolated strain was identified as Bacillus sp. based on its morphological and biochemical characteristics. In this study, the optimal conditions for the production of keratinase by this strain were investigated. The optimal medium composition for the keratinase production was determined to be 3.5% chicken feather as carbon source, 1.0% tryptone as organic nitrogen source, 1.0% $KNO_3$ as inorganic nitrogen source and 0.05% KCl, 0.05% $KH_2PO_4$, 0.03% $K_2HPO_4$ as mineral source and 0.01% yeast extract as growth factor. The optimal temperature and pH was $40^{\circ}C$ and 8.5 with shaking culture (200 rpm), respectively. The maximum keratinase production reached to 123 units/ml after 42 hr of cultivation under the optimal condition. When the hair was used as the sole carbon source, the maximum enzyme activity was 88 units/ml after 120 hr and in this case, the hair added in the medium was not degraded completely but got thinner than the control by 20%.

• Korean Journal of Microbiology
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• v.41 no.1
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• pp.13-17
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• 2005

The aim of this work was to investigate the N-terminal amino acid sequence of catechol 2,3-dioxygenase isolated from Delftia sp. JK-2, which could utilize aniline as sole carbon, nitrogen and energy source. Molecular weight of the enzyme was determined to approximately 35 kDa by SDS-PAGE. N-terminal amino acid sequence of C2,3O from strain JK-2 was $^1MGVMRIGHASLKVMDMDAAVRHYENV^{26}$, and exhibited high sequence similarity with that of C2,3O from Pseudomonas sp., Comamonas sp. JS765, Comamonas test-osteroni, or Burkholderia sp. RP007. Approximately 950-bp C2,3O was obtained through PCR using the primers derived from N-terminal amino acid sequence. Analysis of the DNA sequence revealed that the deduced 296 amino acid sequences were determined, and it showed $100\%$ identity with C2,3O from Pseudomonas sp. AW-2 and $97\%$ similarity with Comamonas sp. JS765.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.135-135
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• 1999

It is well known that Raman spectroscopy is powerful tool in analysis of sp3/sp3 bonding fraction in diamond-like carbon(DLC) films. Raman spectra of DLC film is composed of D-peak centered at 1350cm-1 and G-peak centered at 1530cm-1. The sp3/sp3 fraction is qualitatively acquired by deconvolution method. However, in case of DLC film, it is generally observed that G-peak position shifts toward low wavenumber as th sp3 fraction increases. However, opposite results were frequently observed in ta-C films. ta-C film has much higher residual compressive stress due to its high sp3 fraction compared to the DLC films deposited by CVD method. Effect of residual stress on G-peak position is most recommendable parameter in Raman analysis of ta-C, due to its smallest fitting error among many parameters acquired by peak deconvolution of symmetric spectra. In current study, the effect of residual stress on Raman spectra was quantitatively evaluated by free-hang method. ta-C films of different residual stress were deposited on Si-wafer by modifying DC-bias voltage during deposition. The variation of the G-peak position along the etching depth were observed in the free-hangs of 20~30${\mu}{\textrm}{m}$ etching depth. Mathematical result based on Airy stress function, was compared with experimental results. The more reliable analysis excluding stress-induced shift was possible by elimination of the Raman shift due to residual compressiove stress.

• Korean Journal of Microbiology
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• v.54 no.3
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• pp.266-271
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• 2018

Effect of plasmid curing of Acinetobacter sp. B-W on the production of siderophore from glutamic acid as both carbon and nitrogen sole sources was investigated. Plasmid cured mutant of strain B-W lost the ability to produce siderophore from glutamic acid at $28^{\circ}C$. Transformant E. coli $DH5{\alpha}$ harboring 20 kb plasmid, that was isolated from wild type of strain B-W produced siderophore from glutamic acid as both carbon and nitrogen sole sources at $28^{\circ}C$, but, not at $36^{\circ}C$. Production of siderophore from glutamic acid by transformant E. coli $DH5{\alpha}$ was completely inhibited by $10{\mu}M\;FeCl_3$. In previous report, catechol nature of siderophore produced from glutamic acid by strain B-W was detected by Arnow test. The siderophore produced from glutamic acid by transformant E. coli $DH5{\alpha}$ was also catechol type. Rf value of siderophore produced from transformant E. coli $DH5{\alpha}$ grown in medium glutamic acid as both carbon and nitrogen sole sources at $28^{\circ}C$ was 0.32 in butanol-acetic acid-water (12:3:5) as developing solvent. Rf value of the siderophore was the same with that of wild type of strain B-W. Thus a single plasmid of 20 kb seemed to be involved in the production of siderophore from glutamic acid.

• Journal of Microbiology and Biotechnology
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• v.28 no.2
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• pp.267-274
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• 2018

Lipids in microalgae are energy-rich compounds and considered as an attractive feedstock for biodiesel production. To redirect carbon flux from competing pathways to the fatty acid synthesis pathway of Tetraselmis sp., we used three types of chemical inhibitors that can block the starch synthesis pathway or photorespiration, under nitrogen-sufficient and nitrogen-deficient conditions. The starch synthesis pathway in chloroplasts and the cytosol can be inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea and 1,2-cyclohexane diamine tetraacetic acid (CDTA), respectively. Degradation of glycine into ammonia during photorespiration was blocked by aminooxyacetate (AOA) to maintain biomass concentration. Inhibition of starch synthesis pathways in the cytosol by CDTA increased fatty acid productivity by 27% under nitrogen deficiency, whereas the blocking of photorespiration in mitochondria by AOA was increased by 35% under nitrogen-sufficient conditions. The results of this study indicate that blocking starch or photorespiration pathways may redirect the carbon flux to fatty acid synthesis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.6
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• pp.641-645
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• 1990

In order to study the influence of culture conditions on cell growth and lipid formation by Mucor sp, various carbon and nitrogen sources initial pH and C./N ratio of medium were investigated. Glucose was found to be suitable carbon source in terms of lipid yield and ${\gamma}$-linolenic acid(GLA) content. When NH4Cl and (NH4)2SO4 were used as nitrogen source lipid content was high(19-21%) but GLA content was low(15-17%) On the other hand when NaNO3 and KNO3 were used lipid content was low(about 13%) but GLA content was high(22-23%). The highest production of lipid was obtained at a C/N ratio of 40 using glucose and (NH4)2SO4 as carbon and nitrogen source respectively. it was found that lipid yield was high at pH4.6 Also this fungus did not grow at 35$^{\circ}C$ and lipid yield was highr at 15$^{\circ}C$ than $25^{\circ}C$.

• Journal of the Korean Chemical Society
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• v.34 no.6
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• pp.517-526
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• 1990

The crystal structures of two alditol acetates, D-glucitol hexaacetate and xylitol pentaacetate, have been determined by diffraction methods with Mo-K$\alpha$radiation, using direct methods for phase determinations. The crystal data are: for D-glucitol hexaacetate, P2$_1$, with a = 10.275 (2), b = 8.363 (1), c = 12.560 (5) $\AA;\beta$ = 95.97 $(2)^{\circ}$, Z = 2; for xylitol pentaacetate, P2$_1$/C with a = 18.126 (1), b = 11.422 (2), c = 8.649 (1) $\AA$, $\beta = 95.03 (1)^{\circ}$, Z = 4. Both molecules have extended zigzag carbon chain conformations which differ from previous studies of the structures of D-glucitol and xylitol and also differ from NMR studies on alditol acetates. The bond lengths and angles are normal, with mean values over both structures of C($sp^3)-C(sp^3): 1.514 (10),\; C(sp^3)-O: 1.444 (6),\; C(sp^2)-O: 1.347 (9),\; C(sp^2)=O: 1.197 (6),\; C(sp^2)-C(sp^3): 1.479(9){\AA},\; C(sp^3)-C(sp^3)-C(sp^3): 114.6 (17),\; O-C(sp^3)-C(sp^3): 109.4 (23),\; C(sp^2)-O-C(sp^3): 117.4 (6),\; O=C(sp^2)-O: 122.6 (6),\; C(sp^3)-C(sp^2)-O: 111.8 (7),\; C(sp^3)-C(sp^2)=O: 125.5 (4)^{\circ}$. The atoms of acetate groups are in coplanar. There are no particularly short intermolecular contacts and the molecules are held together by van der Waals force only.