• Nuclear Engineering and Technology
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• v.4 no.3
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• pp.186-193
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• 1972

For efficient micro scale syntheses of Rose $Bengal-^{131}I$, $Hippuran-^{131}I$, and $H.S.A.-^{131}I$, the dependence of labelling yields on pH, on salt contents, and on the volume of buffer solution in the reaction mixtures as well as the reaction apparatus were studied. pH of 5.6 was optimum for preparation of both Rose $Bengal-_{131}I$ and Hippuran $-^{13}I$ but pH of 8.5 was optimum for preparation of $H.S.A.-^{131}I$. Salt in the reaction mixtures hindered drastically the formation of $Hippuran-^{131}I$ but it slightly increased the labelling yield of H.S.A.. The compactly closed reaction vessels were effective for preparations of both Rose $Bengal-^{131}I$and $Hippuran-^{131}I$ in small volume. Thereupon, the labelling procedures were modified to bring about higher labelling yields and better reproducibilities. By these newly established procedures, the labelling yields of Rose $Bengal-^{131}I$ and $Hippuran-^{131}I$ could be increased even with the home-produced sodium $iodide-^{131}I$ solution containing reducing agent.

• Journal of Life Science
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• v.12 no.1
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• pp.77-86
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• 2002

Chitin, a $\beta$-1,4 polymer of N-acetyl-D-glucosamine, is one of the most abundant organic compounds in nature. Chitinase (EC 3.2.1.14) is an enzyme that degrades chitin to chito-oligosaccharides, diacetyl rhitobiose and N-acetyl-D-glucosamine. An extracellular chitinase-producing bacterial strain was isolated from soil and named to as Bacillus subtilis JK-56. Optimum culture condition of B. subtilis JK-56 for the production of chitinase was 1% chitin, 0.5% polypepton, 0.1% KCl, 0.05% MnS $O_4$.4$H_2O$, 37$^{\circ}C$, initial pH 7.0 and 40 hour culture time. When B. subtilis JK-56 was grown in the optimum medium, one major active band and two minor active bands were detected by native-PAGE and active staining of the gel. Among them, the major band was purified from the culture supernatant by 70% ammonium sulfate precipitation and native-PAGE with BIO-RAD Model 491 Prep-Cell and named as Chi-56A. Its molecular weight was estimated to be 53kDa monomer and the isoelectric point (pI) was pH 4.3. The pH and temperature for the optimum activity of Chi-56A were pH 6.0 and $65^{\circ}C$, respectively. Chi-56A was stable up to $65^{\circ}C$ and in alkaline region. Its $K_{m}$ value for colloidal chitin was 17.33g/L. HPLC analysis of the reaction products confirmed that Chi-56A was an exo type chitinase.e.

• Korean Journal of Microbiology
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• v.17 no.2
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• pp.58-64
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• 1979

Studies on some properties of cellulase isolated from Piricularia oryzae. Crude cellulases were prepared from dried rice plant powder (Tong-il, Pal-dal) culture of P. oryzae(N-2, C-8, T-2). The best yield of enzyme was obtained from the medium using Tong-il rice plant powder for P. oryzae cav. N-2 and 2%-sucrose concentration in preculture media. Two units of the enzyme were incubated at $60^{\circ}C$ for 1 hour with 1.0ml, 0.6% Na-CMC. The optimum temperature for the enzyme activity was at $60^{\circ}C$ and the optimum pH was at pH4.0. When Na-CMC was used as substrate the $K_m$ values of crude enzyme were calculated to be $1.05{\times}10^{-4}\;mM\;and\;V_{max}$ was 2.8 mmole/hour. A 10-fold partial purification was achieved by $(NH_4)_2SO_4$ precipitation followed by column chromatography on DEAE Sephadex A-25.

• Journal of the Korean institute of surface engineering
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• v.24 no.4
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• pp.206-214
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• 1991

In the basic study of selective electroless Ni plating of Si wafers, plating rate and physical properties are investigated to obtain optimum conditions of contact hole filling. Si wafers are excellently activated in the concentration of 0.5M IF, 1mM PdCl2, 2mM EDTA at $70^{\circ}C$, 90sec. The optimum condition of Ni-B deposition on p-type Si wafers is 0.1M NiSO4, 0.11M Citrate, $70^{\circ}C$, pH6.8, 8mM DMAB. The main factor in the sheet resistences variation of films is amorphous and on heat treating matrix was transformed into a stable phase (Ni+Ni3B) at $300-400^{\circ}C$. But pH or DMAB concentration in the plating solution doesn't play role of heat-affected phase change.

• Preventive Nutrition and Food Science
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• v.14 no.4
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• pp.323-328
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• 2009

Cryotin F could be used for hydrolyzing shrimp byproducts into bioactive ingredients, which could be used as value-added products. The objective of this study was to investigate the optimum condition for antioxidative activities of the enzymatic hydrolysate produced with Cryotin F using response surface methodology with central composite rotatable design. Shrimp byproducts (shells and heads) were hydrolyzed with Cryotin F. The experimental ranges of the independent variables for 20 experimental runs were 28.2-61.8${^{\circ}C}$ reaction temperature, pH 6-10 and 0.5-5.5% enzyme concentration. The degree of hydrolysis for the reaction products was measured. Their antioxidative activities were measured using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging activity and Fe-chelating activity. The experimental method with central composite rotatable design was well designed to investigate the optimum condition for biofunctional ingredients with antioxidative activities using Cryotin F because of their high R2 values of 0.97 and 0.95 for DPPH-scavenging activity and Fe-chelating activity, respectively. Change in enzyme concentration did not significantly affect their antioxidative activities (p<0.05). Both DPPH scavenging activity and chelating activity against Fe for the enzyme hydrolysates were more affected by the pH of enzyme hydrolysis than by their action temperature. DPPH-scavenging activity was higher at acidic pH than alkali pH, while chelating activity against Few was inversely affected. Hydrolysate of shrimp byproducts showed high antioxidative activities depending on the treatment condition, so the optimum treatment of enzymatic hydrolysate with Cryotin F and other proteases can be applied to shrimp byproducts (shells) and other protein sources for biofunctional ingredients.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.4
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• pp.267-273
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• 2004

The optimization of culture conditions for the bacterium Pseudomonas aeruginosa BYK-2 KCTC 18012P, was performed to increase its rhamnolipid production. The optimum level for carbon, nitrogen sources, temperature and pH, for rhamnolipid production in a flask, were identified as 25 g/L fish oil, 0.01% (w/v) urea, 25 and pH 7.0, respectively. Optimum conditions for batch culture, using a 7-L jar fermentor, were 200 rpm of agitation speed and a 2.0 L/min aeration rate. Under the optimum conditions, on fish oil for 216 h, the final cell and rhamnolipid concentrations were 5.3 g/L and 17.0 g/L respectively. Fed-batch fermentation, with different feeding conditions, was carried out in order to increase, cell growth and rhamnolipid production by the Pseudomonas aeruginosa, BYK-2 KCTC 18012P. When 2.5 g of fish oil and 100 mL basal salts medium, containing 0.01 % (w/v) urea, were fed intermittently during the fermentation, the final cell and rhamnolipid concentrations at 264 h, were 6.1 and 22.7 g/L respectively. The fed-batch culture resulted in a 1.2-fold increase in the dry cell mass and a 1.3-fold increase in rhamnolipid production, compared to the production of the batch culture. The rhamnolipid production-substrate conversion factor (0.75 g/g) was higher than that of the batch culture (0.68 g/g).

• Korean Journal of Microbiology
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• v.40 no.2
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• pp.139-146
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• 2004

A bacterium producing alkaline cellulase was isolated from soil, leaf mold and compost, and was identified as alkalophilic Bacillus sp. HSH-810 by morphological, cultural and biochemical determination. The optimum cul-ture condition of Bacillus sp. HSH-810 for the growth and alkaline cellulase production was $30^{\circ}C$ and pH 10.0. The maximum alkaline cellulase production was obtained when 1.0%(w/v) CMC, 0.5%(w/v) peptone, 0.02%(w/v) $CaCl_2$ and 0.02(w/v) $CoCl_2$ were used as carbon source, nitrogen source and mineral source, respectively. The optimum pH and temperature of the enzyme activity were pH 10.5 and $50^{\circ}C$, respectively. This enzyme was fairly stable in the pH range of 6.0-13.0 and at $50^{\circ}C$. For the effect of surfactants, the activity of alkaline cellulase was stable in the presence of sodium-$\alpha$-olefin sulfonate (AOS), sodium dodecyl sulfonate (SDS), Tween 20 and Tween 80, but inhibited by the presence of 0.1 linear alkyl-benzene sulfonate (LAS) sig-nificantly.

• Applied Biological Chemistry
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• v.13 no.3
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• pp.193-195
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• 1970

The cultural conditions of the osmophilic yeasts for higher concentration of NaCl selected in the previous report were examined and the results obtained were as follows. 1) The strain $T_3\;and\;T_8$ were grown exceedingly well on the media containing 15 percent of NaCl and $T_5\;and\;T_9,\;T_{10}\;and\;T_{11}$ on the media containing 5 percent of NaCl. 2) The optimum temperature for growth of the strain $T_3\;and\;T_5$ was $30^{\circ}C,\;T_8\;T_{10}$ and $T_{11}\;was\;25^{\circ}C\;and\;T_9\;was\;35^{\circ}C.$ 3) Their lethal temperature was $60^{\circ}C$ (treatment for 10 minutes). 4) The optimum pH for growth of the strain $T_3\;and\;T_8$ was pH 4.0, $T_5$ was pH 6.0 and $T_9\;T_9\;and\;T_{11}$ was pH 5.0, respectively.

• Korean Journal of Food Science and Technology
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• v.16 no.1
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• pp.23-28
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• 1984

Anchovy homogenates with or without salt were autolyzed at various pH and temperature conditions. In the initial hydrolysis during 20 hours, the highest autolysis of anchovy homogenate was achieved at pH 4 and $50^{\circ}C$. However, the addition of 20% salt changed the optimum condition to pH 6 and $50^{\circ}C$. When the digestion time was prolonged to 8 days, the most favorable temperature for the autolysis of salted anchovy was lowered to $40^{\circ}C$ compared with $50^{\circ}C$ of initial hydrolysis while the optimum pH was unchanged. Under the best conditions described above, 60.5% of anchovy nitrogen was converted to TCA-soluble nitrogen in 20 hr-incubation without salting, but it was reduced to 49.8% with salting. In the 8 days hydrolysis of salted anchovy, as much as 83.1% of total nitrogen was transformed into TCA-soluble nitrogen. Slight increase in the degree of hydrolysis up to 89.6% was occurred during subsequent ripening period of 52 days at ambient temperature.

• Journal of Life Science
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• v.7 no.3
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• pp.228-233
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• 1997

A thiol protease has been isolated and partially purified from encysted brine shrimp Artemia franciscana using a four-step procedure(filtration, salting out, gel filtration and ion exchange chromatography). The optimum pH of the enzyme for caseinolytic activity was appeared to be 3.0, and the enzymematic activity was stable up to pH 6.0 but lost completely at the pH higher than 8.0. The optimal temperature of the enzyme was appeared to be 35$^{\circ}$C, and ninety percent of the enzyme activity was lost at 45$^{\circ}$C. Various metal ions, e.g., zinc, copper, iron, inhibited the enzyme activity; however, heavy metal chelator, e.g., EDTA, stimulated the enzyme activity. The protease was concluded to be a member of the thiol group protease, since it was inhibited by thiol protease inhibitors and iodoacetate. The protease was also concluded to be a acid protease based on optimum pH.