• Journal of Microbiology
• /
• v.33 no.4
• /
• pp.307-314
• /
• 1995

Trypsin like protease (TLP) and metalloprotease (MTP) were induced in associated with the mycelium differentiation in Streptomyces albidoflavus SMF301. TLP and MTP were purified and characterized from the culture. The molecular mass of TLP and MTP were estimated to be 32 kDa and 18 kDa, respectively. The molecular mass of TLP and MTP were estimated to be 32 kDa and 18 kDa, respectively. The optimum pH and temperature of TLP were 10 and 40.$^{\circ}C$ Those of MTP were 8 and 55 $^{\circ}C$ TLP was stable at alkaline pH (6-9) and unstable above 45.$^{\circ}C$and MTP was stable at alkaline pH and unstable above 80.$^{\circ}C$ Km and Vmax values with benzoyl-arginyl p-nitroanilide of TLP were 139 $\mu$M, and 10 nmole of nitroanilide released per min per$\mu\textrm{g}$ protein, respectively. Km, and Vmax values with a synthetic substrate, leucine p-nitroanilide, or MTP were 58.9 $\mu$M, 3.47 nmol of nitroanilide released per min per$\mu\textrm{g}$protein, respectively. TLP was inhibited competitively by leupeptin; the inhibition constant was 0.0031 $\mu$M. MTP was inhibited by EDTA, phenonthroline and bestatin.

• Proceedings of the KSAR Conference
• /
• 2003.06a
• /
• pp.66-66
• /
• 2003

The aim of this study was to investigate effect of different energy substrates on embryonic development of mouse embryos. Two cell embryos, recovered from ICR female mice (4 weeks old) at 44~52hrs after hCG injection (mated just after hCG injection), were cultured fur 72 hrs in the medium (MEM) supplemented with the three different energy substrates [glucose(G), pyruvate(P) and lactate(L)] and combinations (Control: 0 mM: group A: G 0.5; B: G 3.15; C: P 0.1; D: P 0.32; E: L 5.87; F: L 10.5; G: G0.5+P0.32+L10.5; H: G3.15+P0.1+L5.87; I: G0.5+P0.1+L5.87; J: G3.15+P0.32+L10.5). Blastocysts were stained differentially using PI and bisbenzimide. The 69.8% of the 2 cell embryos cultured in group F were developed the blastocysts. This was the highest (NS) than all other tested groups (44.2~62.8%). Blastocysts, cultured in the group E (60.4$\pm$26.9) and G (58.1$\pm$26.3), had significantly(p<0.05: group E vs. control, B, C, D; G vs. control, A, B, C, D) higher mean cell number compared with the other (42.6$\pm$25.8 ~ 55.2$\pm$31.3) and control (42.6$\pm$25.8) was at the basal level. The proportion of ICM (% ICM of total cells) in blastocysts cultured in group B (26.0$\pm$9.5%), C (29.6$\pm$22.8%) and J (26.0$\pm$11.8%) were significantly higher (p<0.05: control vs. group B, C, J: A vs. C, J; C vs. D, E, I) than those of other tested groups (15.0$\pm$10.6 ~ 23.8$\pm$ 12.9％) and control (15.0$\pm$10.6％) was at the basal level. These results showed that energy substrates supported the development of mouse 2 cell embryos, especially with greater embryo development in high dose of lactate added to media.

• Journal of Microbiology and Biotechnology
• /
• v.13 no.5
• /
• pp.692-699
• /
• 2003

The changes of physicochemical and microbiological states of Myeolchi-jeot, a Korean salted and fermented anchovy, were investigated during 20 days of storage at $4^{\circ}C,\;15^{\circ}C,\;and\;30^{\circ}C$. A total of 314 bacterial strains isolated from Myeolchi-jeot samples at different time intervals were identified, and their abilities to produce biogenic amines were determined by both decarboxylating agar media and HPLC analysis. The salinity and water activity of Myeolchi-jeot changed little, while the pH increased slightly over 20 days at the tested temperatures. A significant increase of total plate count was observed in the sample stored at $30^{\circ}C$. Staphylococcus spp. were dominant in Myeolchi-jeot, and its amine productivity was very weak. Bacillus spp. appeared increasingly with the progress of storage at all temperatures tested, and the increase was considerably dependent on the increase of storage temperature. Also, 58-73%, 83-90%, 81-90%, and 83-93% of Bacillus strains had the ability to produce histamine, tyramine, putrescine, and cadaverine, respectively. Therefore, the main amine producer in Myeolchi-jeot stored for a long period seems to be the genus Bacillus, especially B. licheniformis.

• Korean Journal of Food Science and Technology
• /
• v.25 no.3
• /
• pp.252-257
• /
• 1993

Nine Korean native cattle were purchased from a beef cattle farm. Immediatly after slaughtering and skinning, each carcass was split into left and right sides and the one half was kept as a control, the other one was electrically stimulated by using 400v stimulator for 1 min. All samples were analyzed for shear force value, ATP and biochemical changes to investigate the effect of electrical stimulation during storage at $5^{\circ}C\;and\;15^{\circ}C$. The amount of lactate of electrically stimulated (E.S.) meat showed a rapid increment compared with that of control (p<0.01). E.S. treatment caused a rapid drop of pH value. Initial pH decreased from 6.85 to 6.38 in M. semitendinosus and from 7.0 to 6.58 in Triceps brachii by E.S. treatment (p<0.01). Electrically stimulated muscle showed decrease (34.67%) in ATP to $5.74{\mu}mole/g$ from $8.78{\mu}mole/g$ of unstimulated meat. ATP of the electrically stimulated muscle stored at $15^{\circ}C$ and $5^{\circ}C$ was degraded faster than that of control until 6 hours post-mortem (p<0.05). The tenderness of meat after aging was improved significantly by electrical stimulation with lower shear force value than that of untreated meat (p<0.01).

• Korean Journal of Food Science and Technology
• /
• v.15 no.4
• /
• pp.333-341
• /
• 1983

Tannase of Aspergillus sp. AN-11 isolated from contaminated acorns was purified by a procedure involving ammonium sulfate precipitation, DEAE-cellulose column chromatography and Sephadex G-200 gel filtration. Physiochemical properties of the purified tannase was investigated. Tannase was purified about 37 folds with the yield of 49% from the culture broth of Aspergillus sp. AN-11. The purified tannase was homogeneous on polyacrylamide gel disc electrophoresis and was dissociable into two identical subunits on SDS-polyacrylamide gel electrophoresis. The molecular weight of the tannase was determined to be 200,000 by gel filtration on Sephadex G-200. The purified tannase showed a typical protein ultraviolet spectrum. The enzyme had a optimum pH 5.5 and optimum temperature at 30 to $40^{\circ}C$. The enzyme was stable at a pH range from 5.0 to 6.5 and at the temperature below $30^{\circ}C$. The enzyme was inactivated remarkably by $CuCl_2$ and $ZnCl_2. The Km value of the enzyme was $7.58{\times}10^{-4}\;M$.

• Journal of Applied Biological Chemistry
• /
• v.59 no.1
• /
• pp.75-81
• /
• 2016

Glutaraldehyde was used as a cross-linking agent for immobilization of purified ${\alpha}$-amylase from Exiguobacterium sp. DAU5. Befitting concentration of glutaradehyde and cross-linking time is the key to preparation of cross-linking chitosan beads. Based on optimized immobilization condition for ${\alpha}$-amylase, an overall yield of 56% with specific activity of 2,240 U/g on chitosan beads and 58% with specific activity of 2,320 U/g on chitosan-carbon beads was obtained. The optimal temperature and pH of each immobilized enzyme activity were $50^{\circ}C$ and 50 mM glycine-NaOH buffer pH 8.5, respectively. Those retained more than 75 and 90% of its maximal enzyme activity at pH 7.0-9.5 and after incubation at $50^{\circ}C$ for 1 h, respectively. In addition, the immobilization product showed higher organic-solvent tolerance than free enzymes. The mode of hydrolyzing soluble starch revealed that the ${\alpha}$-amylase possessed high hydrolyzing activity. These results indicate that chitosan is good support and has broad application prospects of enzyme immobilization.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.11
• /
• pp.1501-1509
• /
• 2012

A novel bacterial strain, MG7, with high cellulase activity was isolated and identified by morphological characteristics and molecular phylogeny analysis as Paenibacillus barcinonensis. Maximum production of cellulase by MG7 was observed at pH 7.0 and $35^{\circ}C$. The enzyme was purified with a specific activity of 16.88 U/mg, the cellulase activity was observed in a zymogram, and its molecular mass (58.6 kDa) was confirmed by SDS-PAGE. The purified enzyme showed maximum activity at pH 6.0 and $65^{\circ}C$ and degraded cellulosic substrates such as carboxy methyl cellulose (CMC), Avicel, filter paper, and ${\beta}$-glucan. The enzyme showed stability with 0.5% concentration of various surfactants. The $K_m$ and $V_{max}$ of cellulase for CMC and Avicel were found to be 0.459mg/ml and 10.46mg/ml/h, and 1.01 mg/ml and 10.0 mg/ml/h, respectively. The high catalytic activity and its stability to temperature, pH, surfactants, and metal ions indicated that the cellulase enzyme by MG7 is a good candidate for biotechnological applications.

• Journal of the Korean Ceramic Society
• /
• v.20 no.1
• /
• pp.31-36
• /
• 1983

The photoelectrochemical conversion by polycrystalline $TiO_2$ electrodes is effected by applied voltage oxidized $TiO_2$ thickness temperature and concentration of a, P. E. C cell. Anodic current starts at -0.8V in 1N-NaOH solu-tion and photocurrent appears around 420nm frequency. And the emf of the cell drops with the rate of 58.5mV/PH.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.5
• /
• pp.1475-1482
• /
• 2011

New spiro[benzo[c]fluorene-7,9'-fluorene] (SBFF)-based blue host materials, 9-phenyl-SBFF (BH-4P) and 5,9-diphenyl-SBFF (BH-6DP), were successfully prepared by spiro-formation of 9-phenyl-7H-benzo[c]fluoren-7-one with 2-bromobiphenyl via lithiation and reaction of 5,9-dibromo-SBFF with phenylboronic acid through the Suzuki reaction, respectively. Diphenyl-[4-(2-[1,1;4,1]terphenyl-4-yl-vinyl)-phenyl]-amine (BD-1) and N,N-diphenyl-N',N'-diphenyl-SBFF-5,9-diamine (BD-6DPA) were used as dopant materials. Blue OLEDs with the configuration ITO/N,N'-bis-[4-(di-m-tolylamino)phenyl]-N,N'-diphenylbiphenyl-4,4'-diamine (DNTPD)/bis[N-(1-naphthyl)-N-phenyl]benzidine (NPB)/host:5% dopant/SFC-137/Al-LiF were prepared from the two host materials doped with BD-1 and BD-6DPA dopants and the devices composed of BH-4P and BH-6DP doped with BD-6DPA showed blue EL spectra at 458 and 463 nm at 7 V and luminance efficiencies of 4.58 and 4.88 cd/A, respectively.

• Korean Journal of Food Science and Technology
• /
• v.31 no.4
• /
• pp.1017-1023
• /
• 1999

Several extraction conditions of mussel were investigated for preparation of the extract as a natural shellfish seasoning. The conditions studied were extraction temperature and time, addition of sodium phosphates and citrate and hydrolysis with commercial proteolytic enzymes. The extracts were prepared by deshelling, grinding and aqueous extraction followed by centrifugation and filtration. Extraction at $90^{\circ}C$ for 40min showed the highest solids yield with less fishy and high umami taste. Among the several phosphates and citrate added, $Na_{3}PO_{4}$ and $Na_{4}P_{2}O_{7}$ at 1% level were most effective in terms of the yield and umami taste. The pH effects showed that pH 10 resulted the highest solids yield of 28% with less fishy taste. Even though the effect of enzymatic hydrolysis was not greatly different among the commercial enzymes tested, Protamex and Protease II were somewhat better than other enzymes in taste. When the mussel were extracted by the combined conditions, hydrolysis with Protamex followed by extraction at $90^{\circ}C$ for 40min with addition of $Na_{3}PO_{4}$ at pH 10, the solid yields increased up to 30% which was about 58% improvement and high intensity of umami taste and less fishy flavor.