• The Korean Journal of Mycology
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• v.10 no.2
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• pp.67-73
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• 1982

The $(NH_4)_2\;SO_4$ (70%) treated crude enzymes from the culture filtrates of the$C-7^{+t}$ strain of Pyricularia oryzae which was grown on 2% CMC (carboxymethyl cellulose) for 8 days at $28^{\circ}C$ were chromatographied on Sephadex G-150 and DEAE-Sephadex A-25 columns. From the chromatography, three fractions of CMCase$(C_x)$ was examined using Na-CMC as substrate. The $C_x$ enzyme activity was optimal at pH 6.0 and $40^{\circ}C$, stable up to $40^{\circ}C$. The values of Km and Vmax of the enzyme were $2.8{\times}10\;mM$ and 5.9m moles/hour, respectively. The molecular weight determined by Sephadex G-150 column chromatography was around 80,000. Approximately sevenfold purified $C_x$ enzyme gave a single protein band on the polyacrylamide gel electrophoresis.

• Membrane Journal
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• v.28 no.5
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• pp.361-367
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• 2018

In this study, the nanofiltration (NF) composite membranes for the low pressure use were prepared using polyvinylidene fluoride (PVDF) hollow fiber membrane as a supporter. Poly styrene sulfonic acid (PSSA) and polyethyleneimine (PEI) were coated onto the PVDF membrane by both layer-by-layer and salting-out methods. To characterize the prepared NF membranes in terms of the flux and salt rejection, 100 mg/L feed solutions of NaCl, $MgCl_2$, and $CaSO_4$ were used at the flow rate of 1 L/min and the operating pressure of 2 bar at room temperature. The NF membranes coated with 20,000 ppm PSSA (ionic strength 1.0) solution for 3 minutes and then 30,000 ppm (ionic strength 0.1) solution for 1 minute were observed the best performance. The permeability and salt rejection were 38.5 LMH, 57.1% for NaCl, 37.9 LMH and 90.2% for $MgCl_2$ and 32.4 LMH and 54.6% for $CaSO_4$, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.537-546
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• 1986

In the previous paper(Kim et al, 1986), the alkaline proteinase from the pyloric caeca of mackerel was shown relatively strong activity in the alkaline pH range. Therefore purification of the enzyme has been undertaken to identify the proteolytic enzyme and three alkaline proteinases were isolated by ammonium sulfate fractionation, DEAE-Sephadex A-50 column chromatography and Sephadex G-100 gel filtration. One percent sodium chloride solution was the most effective for the extraction of alkaline proteinase from the pyloric caeca of mackerel. Three alkaline proteinases temporarily designated Enz. A, B and C were isolated from the pyloric caeca of mackerel, and identified to be homogeneous with electrophoresis. The specific activity of the purified Enz. A, B and C was increased to 34, 53 and 37-fold over the crude enzyme solution, respectively. Yield of them was 1.6, 2.1 and $1.5\%$, respectively, and a combined yield was $5.2\%$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.2
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• pp.68-74
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• 1983

A moderately halophilic bacterium, Listeria denitrificans HB-38, isolated from mud on the seashore in Sooyoung bay, Pusan, showed the requirement of $4\%$ sodium chloride for cell growth in a medium with salts typical of a marine environment, and showed that of $10\%$ in a medium with salts typical of a terrestrial environment. The optimum temperature and pH for growth were $40^{circ}C$ and pH 7.5 in the medium containing $10\%$ sodium chloride and ions typical of a terrestrial environment. Sodium chloride as a protoplast stabilizer gave more stability than sorbitol or sucrose, meanwhile the protoplast did not require higher concentration of stabilizer than that of E. coli protoplast. Succinic dehydrogenase of HB-38 had a halophilic property showing maximal activity in the presence of $9\%$ sodium chloride. The strain HB-38 did not harbor an extrach-romosomal DNA.

• Korean Journal of Agricultural Science
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• v.21 no.1
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• pp.11-21
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• 1994

The halophile, Micrococcus sp. which produces RNase was isolated from salted and fermented food. The optimum growth condition of the Micrococcus sp. in pH 7.0 of complex medium containing 2M NaCl, and at $35^{\circ}C$. Optimum condition for enzyme production by this strain was when it was grown in the CM medium, containing 2% yeast extract, 1.5% casamino acid and 2M NaCl in the initial pH 8.5 for 2 days. The maximal RNase activity was observed at pH 8.0 and $55^{\circ}C$. The Km value for RNA was determined to be 5mg/ml by Lineweaver-Burk plot. The RNase activity in the absence of NaCl was maximum, but it was completely lost by adding of 1.25M NaCl and it was increased above 1.25M to 2.5M NaCl. When 2.5M NaCl was added, the activity of RNase showed 45% of maximum value.

• Microbiology and Biotechnology Letters
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• v.30 no.1
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• pp.26-32
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• 2002

For commercial production of Korean fermented anchovy sauce through rapid fermentation, a bacterial strain which showed the high protease activity was isolated from a commercially fermented anchovy sauce. The isolate was Bacillus amyloliquefaciens, and named as B. amyloliquefaciens HTP-8. The incubation temperature, initial pH, and cultivation time for optimal production of protease by B. amyloliquefaciens HTP-8 were $30^{\circ}C$, 7.0, and 3 days, respectively. In jar fermenter, B. amyloliquefaciens HTP-8 showed higher protease activity when grown at pH 7.0. The protease was partially purified by 80% ammonium sulfate precipitation and CM-Sephadex C-50 ion exchange chromatography. The partially purified enzyme had specific activity of 103.3 units/mg, yield of 0.4%, and purification fold of 43.0. The optimal pH and temperature for the protease activity were 10.0 and $50^{\circ}C$, respectively. The protease was relatively stable at the pH range of 7.0~12.0 and at the temperatures below 4$0^{\circ}C$. The activity of the enzyme was inhibited by $Ag^{＋}$ /, $Ba^{2＋}$ and selectively inhibited by PMSF, suggesting that it is a serine protease.

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.321-327
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• 1985

Cultivation conditions for the production of extracellular alkaline protease by a nonpiamentation Serratia sp. and purification of the enzyme were studied. The maximum enzyme level was obtained at the beginning of stationary phase when the organism was cultured on brain heart infusion medium at $25^{\circ}C$ under aeration (gyratory shaking, 180 cycles/min). The enzyme was purified about 100 fold with 16.5％ yield by ammonium sulfate precipitation, ammonium sulfate fractionation followed by DEAE-cellulose chromatography (1st and 2nd). The purified enzyme moved as a single symmetrical peak in the analytical ultracentrifuge. The enzyme demonstrated its maximum activity at pH 8.5-9.0 and 4$0^{\circ}C$ when vitamin-free casein was used as a substrate.

• Membrane Journal
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• v.29 no.2
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• pp.96-104
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• 2019

The purpose of this paper is whether or not the in-situ restoration of the reverse osmosis (RO) membranes which its membrane function is lost is possible. The damaged RO membranes are double coated through the salting-out method by the poly(styrene sulfonic acid) sodium salt as the cationic exchange polymer and the polyethyleneimine as the anionic exchange polymer and also conducted the opposite order of the coating materials. And according to the concentration, time and ionic strength, the flux and rejection are measured for the coated membranes. Then the best coating condition is to apply for the RO membrane module of the household water purifier to know the possibility of the in-situ restoration for the commercial module. When the condition of the PEI 30,000 ppm (IS = 0.1)/PSSA 20,000 ppm (IS = 0.7) is applied, the rejection was enhance from 69% for the damaged module to 86% (90% for the pristine module).

• Composites Research
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• v.32 no.3
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• pp.134-140
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• 2019

Graphene nanoplatelets (GNP), one of the graphene derivatives is famous as the most proper candidate for industrial applications. However, current performance of GNPs as reinforcing filler in composites is limited by their agglomeration and physicochemical heterogeneity. Herein, an approach to produce non-covalently functionalized GNPs (F-GNPs) is reported which possesses potential to be extended as the industrial level of mass production. The one-step functionalization process uses melamine, a low-cost chemical, to prevent agglomeration and dispersion in polar solvents. Furthermore, a purification strategy called salting-out process based on differences in the dispersibility of the individual F-GNP flakes is reported to separate F-GNPs. The functionalization and separation process developed in this paper provides a strategy to use GNPs at the industrial level in composite applications.

• Analytical Science and Technology
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• v.21 no.2
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• pp.84-92
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• 2008

A method for the determination of trace amount of caffeine in urine and various drink samples using hollow fiber-liquid phase microextraction (HF-LPME) and capillary gas chromatograph/nitrogen phosphorus detector (GC/NPD) has been established. HF-LPME method has been optimized with respect to several experimental parameters including the effects of the hollow fiber length, extraction solvent, stirring mode, pH and salt concentration for the determination of caffeine from aqueous samples. The correlation coefficient of calibration curve for caffeine was 0.9994. The average recovery was 102%(n=3). The established method is feasible for the determination of trace amounts of caffeine in several aqueous sample. The limit of detection (LOD) and the limit of quantitation (LOQ) have been found to be 2.5 and 10 ng/mL, respectively. The established HF-LPME method for the analysis of caffeine from aqueous sample can be used for the determination of biological, food and environmental samples.