• The Korean Journal of Mycology
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• v.11 no.3
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• pp.109-114
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• 1983

${\beta}-Galactosidase$ activity of Aspergillus phoenicis was studied using ONPG and lactose as substrate. It increased monotonically during the exponential growth phase and dropped rapidly at the beginning of the stationary one. It exhibited high tolerable temperature and acidic optimal pH which provides certain advantages from the industrial view point. Enzyme of ${\beta}-galactosidase$ had more subsrate affinity for ONPG than for lactose and its apparent maximum activity was also higher with the former as substrate. Activity of this enzyme depended upon the conditions of immobilization. Optimum crosslinking reaction was occurred at pH 7.2 and 0. 35 vol. % of glutaraldehyde concentration.

• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.172-176
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• 2006

Fe(III)-Coated Star Fish (ICSF) was prepared by reaction of calcined Star Fish (SF) with Fe(III) solution at an elevated temperature. To investigate the stability of ICSF at acidic condition, dissolution of Fe was studied at pH 2 as a function of time. Extracted iron was negligible over the entire reaction time. This stability test suggests the applicability of ICSF in the treatment of wastewater even at low pH. Adsorption capacity of Cu(II) onto SF and ICSF was investigated in a batch and a column test. In the pH-edge adsorption, adsorption of copper onto SF and ICSF was quite similar over the entire pH range due to the presence of an important amount of Fe in SF itself. From the adsorption isotherm obtained with variation of the concentration of Cu(II), ICSF showed 1.6 times greater adsorption capacity than SF. Also, ICSF showed a greater removal capacity of Cu(II) in the column test.

• Journal of Microbiology and Biotechnology
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• v.2 no.1
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• pp.14-20
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• 1992

Some microorganisms isolated from soil, including some bacteria and fungi, were found to secrete an extracellular soymilk-clotting enzyme. Among them, an isolated fungus showed the highest soymilk-clotting activity and the strain was assigned to genus Penicillium based on its cultural and morphological characteristics, and designated as Penicillium sp. L-151K. Soymilk-clotting enzymes A and B produced by Penicillium sp. L-151K were purified by ammonium sulfate precipitation and chromatographies on Sephadex G-25, CM-Sephadex, Sephadex G-100 and phenyl-Toyopearl gel. The two purified enzymes A and B were found to be homogeneous by polyacrylamide gel electrophoresis at pH 9.5. The molecular weights of enzyme A and B were 24, 000 and 40, 000, respectively, by gel filtration on Sephadex G-100. Enzymes A and B coagulated soymilk optimally at $60^\circ{C}$ and were stable up to $50^\circ{C}$. Both enzymes were most active at pH 5.8 for soymilk coagulation, and were stable with approximately 80% of original activity from pH 3.0 to 5.0. Each enzyme was an acidic protease with an optimum pH of 3.0 for casein digestion. The soymilk-clotting efficiency of these enzymes was improved with $CaCl_2\;or\;MgCl_2$ when making soymilk-curd.

• Journal of the Korean Chemical Society
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• v.28 no.3
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• pp.176-184
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• 1984

Retention behavior of benzoic acid and its derivatives on XAD-2 in the alcoholic aqueous solution was investigated and separation was attempted. Retention was affected by the concentration and kinds of added organic solvents, the pH of the aqueous solution, the added $R_4N^+$ and the position and kinds of functional group in the sample molecules. Retention of sample acids in acidic conditions was due to mainly molecular adsorption on nonpolar XAD-2 surface and that in basic conditions was due to mainly ion-pair model. In these bases a mixed sample was separated in EtOH 20% aqueous solution at pH 8.50.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1349-1351
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• 2008

This study examined the effects of temperature, D-psicose concentration, pH, and various amino acids on the Maillard browning reaction of D-psicose and glycine mixture and compared browning color intensity with those of other sugars, such as sucrose, D-glucose, D-fructose, and D-tagatose. When D-psicose (0.1 M) and glycine (0.1 M) mixture was heated at $70-100^{\circ}C$ for 5 hr, the absorbance at 420 nm increased with increasing reaction temperature and time. The Hunter a, b values, and color difference (${\Delta}E$) increased with increasing D-psicose concentration and pH within the range of pH 3-7 except at pH 6, while the L value decreased. The rate of Maillard browning reaction was in order of D-tagatose>D-psicose $\fallingdotseq$ D-fructose>D-glucose>sucrose. The browning color intensity of the D-psicose-basic and non-polar amino acids mixtures was higher than that of the D-psicose-acidic amino acids.

• Textile Coloration and Finishing
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• v.7 no.3
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• pp.60-67
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• 1995

This study was made to investigate the effect of silk fabrics treated with mimosa and tannic acid-weighting effect, surface color according to temprature, treatment time, concentration, pH. The results were as follows ; 1. The wavelength of maximum absorption of mimosa and tannic acid solution appeared at 278.5nm and 275.0nm, respectively. By the irradiation, spectra at wavelength of maximum absorption of mimosa solution disappeared, but those of tannic acid solution decreased after 48hr irradiation. 2. The tannin weighting increased with the increase of concentration, treatment temperature at 8$0^{\circ}C$, acidic condition. In case of tannic acid, it was higher than mimosa. 3. Surface color of silk fabric with mimosa changed from 2.8YR to 5.8YR acc-ording to the increase o( tannin concentration but in case of tannic acid itchanged from 4.2Y to 3.9Y. It was more changed acidic or alkaline conditionthan origine solution.

• Bulletin of the Korean Chemical Society
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• v.31 no.1
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• pp.82-86
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• 2010

Quinine (QN) is a weak anion-exchange type chiral selector and QN-based silica stationary phases have been widely used for enantioseparation of acidic chiral analytes in HPLC and recently in CEC. In this work we report enantioseparation of non-acidic chiral analytes on a quinine carbamate-immobilized zirconia (QNZ) in reversed-phase (RP) CEC. Influences of pH, composition of the buffer, acetonitrile content and the applied voltage on enantioseparation were examined. Enantiomers of the analytes investigated are well separated in acetonitrile/phosphate buffer mobile phases. Separation data on QNZ were compared to those on QN-bonded silica (QNS). Retention was longer but better enantioselectivity and resolution were obtained on QNZ than QNS.

• Journal of Ginseng Research
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• v.17 no.3
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• pp.228-231
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• 1993

Physicochemival properties of ginseng roasted at 170 to $250^{\circ}C$ were investigated. Soluble solid contents in roast ginseng increased until $200^{\circ}C$, but decreased at higher temperature than $200^{\circ}C$. Contents of reducing sugar and protein were decreased and pH values were dropped, while optical density, acidic polysaccharide contents, precursor of brown pigments and hydrogen donating activities by DPPH were increased according to increasing in roast temperatures. The color distribution of roast ginseng expressed as Hunter L, a and b values demonstrated that lower L values and higher a values were observed according to higher temperature, but b values were almost not changed.

• Bulletin of the Korean Chemical Society
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• v.14 no.4
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• pp.444-449
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• 1993

Anaerobic oxidation of D-penicillamine by Fe(III) in acidic solution has been studied kinetically by the use of stopped-flow system. The reaction is biphasic with a rapid complexation of 1: 1 complex, $Fepen^+$ (pen= D-penicillamine dianion) which is then internally reduced to Fe(II) and disulfide. Rates of both the complexation and the redox process are pH dependent and also are affected by the presence of chloride ion. Different from the reaction of Cu(II) with D-penicillamine, partially oxidized mixed-valence complex is not formed even transiently in this reaction.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.4
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• pp.269-278
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• 2005

In order to produce only a pH-controlled solution without discharging any unwanted solution, this work has developed a continuous electrolytic system with a pH-adjustment reservoir being placed before an ion exchange membrane-equipped electrolyzer, where as a target solution was fed into the pH-adjustment reservoir, some portion of the solution in the pH-adjustment reservoir was circulated through the cathodic or anodic chamber of the electrolyzer depending on the type of the ion exchange membrane used, and some other portion of the solution in the pH-adjustment reservoir was discharged from the electrolytic system through the other counter chamber with its pH being controlled. The internal circulation of the pH-adjustment reservoir solution through the anodic chamber in the case of using a cation exchange membrane and that through the cathodic chamber in the case of using an anion exchange membrane could make the solution discharged from the other counter chamber effectively acidic and basic, respectively. The phenomena of the pH being controlled in the system could be explained by the electro-migration of the ion species in the solution through the ion exchange membrane under a cell potential difference between anode and cathode and its consequently-occurring non-charge equilibriums and electrolytic water- split reactions in the anodic and cathodic chambers.