• Microbiology and Biotechnology Letters
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• v.26 no.1
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• pp.15-22
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• 1998

The dnrF gene, responsible for conversion of aklavinone to $\varepsilon$-rhodomycinone via C-11 hydroxylation, was mapped in the daunorubicin gene cluster of Streptomyces peucetius subsp. caesius ATCC 27952, close to drrAB, one of the anthracycline resistance genes. To characterize the enzymatic properties of the aklavinone 11-hydroxylase, the dnrF gene was overexpressed in Escherchia coli. The pET-22(+) plasmid which has the T7 promoter under the control of lacUV5 gene was used for the overexpression of the dnrF gene, and the recombinant plasmid pET213 that contains the dnrF gene linked to the T7 promoter of pET-22b(+) was introduced into the E. coli BL2l. When the expression of the dnrF gene was induced by IPTG at the final concentration of 1 mM, the induced protein could be detected in SDS-PAGE only in insoluble precipitate. The insoluble protein was electroeluted from the gel and used for the preparation of antiserum in mice. Various culture conditions were tested to maximize the expression of the aklavinone 11-hydroxylase in soluble form. The enzymatic activity was checked by the bioconversion experiment, and the protein was confirmed by the SDS-PAGE and the Western blot analysis. From the analysis of the data, it was concluded that the culture induced with IPTG at the final concentration of 0.02 mM at 37$^{\circ}C$ yielded the best productivity of active form of enzyme.

• Applied Microscopy
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• v.33 no.4
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• pp.261-266
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• 2003

The growth patterns of primary culture of bovine brain microvessel endothelial cells (BBMECs) were studied using electron microscopy when grown on $3.0{\mu}m$ and $0.4{\mu}m$ pore Transwell. The capillary fragments and isolated endothelial cells grew on collagen coated culture plate and Transwell membrane. The BBMECs grew only on the upper surface of membrane of $0.4{\mu}m$. But BBMECs on $3.0{\mu}m$ pore membrane migrated through the pore and grew on the opposite side of the membrane. In summary, BBMECs isolated by enzyme digestion could migrate through $3.0{\mu}m$ pore membrane but not through $0.4{\mu}m$ pore membrane. So $0.4{\mu}m$ pore membrane instead of $3{\mu}m$ pore membrane should be used for drug transport experiment or transendothelial electrical resistance measurement.

• Journal of the Korean Wood Science and Technology
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• v.39 no.3
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• pp.221-229
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• 2011

Due to the increase of oil price and the environmental issue such as the emission of volatile organic compounds, the necessity for developing alternative resins of petroleum-based adhesive resins, which have extensively been used for the manufacture of wood-based products, has been speculation since the early 1990. In our study, rapeseed flour (RSF), which is the by-product of bio-diesel produced from rapeseed, were hydrolyzed by enzymes. As a crosslinking agents of the RSF hydrolyzates, phenol-formaldehyde prepolymers (PF) were prepared. The RSF hydrolyzates and PF were mixed to complete the formulation of RSF-based adhesive resins, and the resins were applied to make the laminated veneer lumber (LVL). The physical and mechanical properties of the LVL were measured to examine whether RSF can be used as raw materials of adhesive resins for the fabrication of LVL or not. The average moisture content and soaking delamination rate of the LVL bonded with RSF-based adhesive resins exceeded the minimum requirement of KS standard. Moreover, thermal analysis of the RSF-based resins showed similar tendencies except for the RSF-based adhesive resins formulated with pectinase-hydrolyzed RSF. The bending strengths of the LVL were higher than that of the LVL made with commercial PF resins. These results showed the potential of RSF as a raw material of alternative adhesives for the production of LVL. Further works on the optimal conditions of RSF hydrolysis and spreading characteristics for RSF-based adhesive resins is required to improve the adhesive performance of RSF-based resins.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.132-137
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• 2018

Enzymatic treatments of maize flour (MF) were investigated using commercial carbohydrases (Ultraflo L and Pentopan 500 BG) to enhance the phenolic acid content and antioxidant property. The total phenolic acid content of the MF was 3.76 mg/100 g, whereas those of the Pentopan 500 BG and Ultraflo L treated MF were 6.85 and 39.55 mg/100 g, respectively. Particularly, ferulic acid content of Pentopan 500 BG-treated MF was 20.0 times higher than that of untreated MF (1.7 vs. 33.9 mg/100 g). Pentopan 500 BG appeared to be more effective than Ultraflo L in increasing the free phenolic acid content. Antioxidant activities of enzyme treated MF were significantly higher than untreated MF. In particular, the Pentopan 500 BG-treated MF (16.0 mmol TE/100 g) was approximately 1.5 times higher than untreated MF (12.6 mmol TE/100 g). Enzymatic hydrolysis of cell wall polysaccharides in MF could be used as an effective procedure for not only increasing phenolic content but also antioxidant activities.

• Journal of Life Science
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• v.19 no.12
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• pp.1724-1730
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• 2009

The mannanase-producing bacteria, designated CS47, was isolated from the fresh feces of three horses (from a farm in Jinju National University). The isolate CS47 was facultatively anaerobic and grew at temperatures ranging from $20^{\circ}C$ to $50^{\circ}C$ with an optimal temperature of $38^{\circ}C$. The DNA G+C content of the isolate CS47 was 44 mlo%. The major fatty acids were anteiso-15:0 (39.6%), 17:0 (7.6%), and iso-15:0 (37.8%). The 16S rRNA gene sequence similarity between the isolate CS47 and other Bacillus strains varied from 93% to 98%. In the phylogenetic analysis based on these sequences, the isolate CS47 and Bacillus amyloliquefaciens clustered within a group and separated from other species of Bacillus. Based on the physiological and molecular properties, the isolate CS47 was classified within the genus Bacillus as Bacillus amyloliquefaciens CS47. The optimal pH and temperature for mannanase activity of B. amyloliquefaciens CS47 were pH 6.0 and $50^{\circ}C$, respectively. The thermal stability of mannanase from B. amyloliquefaciens CS47 is valuable when using this enzyme in industrial application.

• Food Science of Animal Resources
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• v.25 no.3
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• pp.357-364
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• 2005

To search probiotic microorganisms, we isolated Lactobacillus sp. from kefir, The Lactobacillus sp. strain showed $99.5\%$ of identity to species Lactobacillus rhamnosus by API kit. Lactobacillus rhamnosus showed high resistances to acidic environment, which grew well even at pH 2.0 and $1.0\%$ bile salt Enzyme activity of Lactobacillus rhamnosus was higher in amylase ($0.673\;{\mu}mol/min/mg$) than that in xylanase ($0.288\;{\mu}mol/min/mg$), cellulase($0.117\;{\mu}mol/min/mg$) and phytase($0.269\;{\mu}mol/min/mg$). Especially, the Lactobacillus rhamnosus showed high heat stability which remained $1{\times}10^6\;CFU/ml$ at $60^{\circ}C$. The maximum numbers of Lactobacillus rhamnosus on growth owe was reached at 24 h fermentation and pH was decreased to 4.6. The resistances of Lactobacillus rhamnosus to acidic pH and bile salt were better than that of Lactobacillus acidophilus used as control. When Lactobacillus rhamnosus was cultured with E. coli in MRS broth, E. coli was disappeared after 18 h. These result suggest that the isolated Lactobacillus rhamnosus has a useful probiotics properties.

• Korean journal of food and cookery science
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• v.26 no.3
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• pp.323-329
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• 2010

Studies on the tenderizing effect of fruits has been limited even though fig, kiwifruit, pear, and pineapple cultivated in Korea are utilized commonly during cooking for their proteolytic properties. Therefore, the characteristics of these fruits were investigated by treating beef with their crude protease extracts. The protease effects of crude protease extract from the fruits on casein and myofibrilar protein were in the following order : pineapple > kiwifruit > fig > pear. Electrophoretic analysis results found that pineapple, kiwifruit, and fig cleaved myosin heavy chain into smaller fragments. The myofibrilar fragmentation ratio of crude protease extracts was the highest for pineapple whileas the lowest for pear. Ground fruits (5% and 10%) increased amounts of soluble nitrogen and decreased shear force of beef. Pineapple was the most effective while pear was the least effective. Decrease in springiness and gumminess was observed by texture profile analysis of beef treated with fruits, especially pineapple and kiwifruit. Among the 5% treatments, pineapple and kiwifruit produced the highest tenderness. Additionally, 10% treatment was less preferable than the 5% treatment.

• Korean Journal of Microbiology
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• v.51 no.2
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• pp.169-176
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• 2015

The malolactic fermentation (MLF), which is widely used in winemaking, is the conversion of malic acid to lactic acid conducted by the malolactic enzyme (Mle) of lactic acid bacteria. In order to select the strains with MLF among 54 lactic acid bacteria isolated from the traditionally fermented foods, we designed a primer set that specifically targets the conserved regions of the mle gene and then selected four strains that harbor the mle gene of Lactobacillus plantarum. All strains were identified as L. plantarum by analyzing the 16S rRNA sequences, biochemical properties, and the PCR products of the recA gene. From comparison of the mle gene sequences consisting of 1,644 bp, the nucleotide and amino acid sequence of strain JBE60 correspond to 96.7% and 99.5% with those of other three strains, respectively. The strain JBE60 showed the highest resistant against 10% (v/v) ethanol among the strains. The strains lowered the concentration of malic acid to average 43%. Considering the ethanol resistance and conversion of malic acid, the strain JBE60 is considered as a potential starter for the malolactic fermentation.

• Korean Journal of Microbiology
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• v.51 no.2
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• pp.141-147
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• 2015

Four halophilic bacteria were isolated from a salt water tank of more than 25% above salinity used for production of salt. HJS1 and HJS6 strains were identified as having ${\beta}$-glucosidase producing capabilities at high salinity. ${\beta}$-Glucosidase produced from these bacterial strains showed the best activity at 56-79 U/ml in NaCl (0-5%), showing the highest ${\beta}$-glucosidase activity at NaCl 3%. A salt tolerant ${\beta}$-glucosidase can maintain at least 75% activity of the enzyme in 0-20% NaCl concentration. The 16S rRNA gene sequences of strains HJS1 and HJS6 shows 99.8% similarity with Roseivivax roseus $BH87090^T$. Those sequences were registered as AB971835 and AB971836 in the NCBI GenBank. DNA-DNA hybridization test revealed that both strains showed 90.1 to 90.3% hybridization values with R. roseus $BH87090^T$, which was the closest phylogenetic neighbor. Major Cellular fatty acids of strains HJS1 and HJS6 were $C_{16:0}$, $C_{18:1}$ ${\omega}7c$, $C_{19:0}$ cyclo ${\omega}8c$ and 11-methyl $C_{18:1}$ and the major quinone was Q-10. Their fatty acid composition and quinone were very similar to Roseivivax roseus $BH87090^T$. Meanwhile, Roseivivax roseus $BH87090^T$ did not produce any ${\beta}$-glucosidase. Based on the molecular and chemotaxonomic properties, strains HJS1 and HJS6 were identified as members of Roseivivax roseus.

• Journal of Animal Science and Technology
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• v.51 no.2
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• pp.171-176
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• 2009

A bacterial strain producing intracellular phytase was isolated from cultivable soil near cowsheds and identified as a fluorescent Pseudomonas sp. BUN1. The BUN1 phytase, partially purified by cation and anion exchange chromatography, exhibited its optimal activity at $40^{\circ}C$ and pH 5.5. As for substrate specificity, it was very specific for phytate and showed little activity on other phosphorylated conjugates. Its activity was greatly inhibited by metal ions such as $Cu^{2+}$, $Cd^{2+}$, and $Zn^{2+}$. Addition of corn starch to PSM (phytasesynthetic medium) [0.5% sodium phytate, 0.5% $(NH_4)_2SO_4$, 0.5% KCl, 0.01% $MgSO_4\cdot7H_2O$, 0.01% $CaCl_2\cdot2H_2O$, 0.01% NaCl, 0.001% $FeSO_4\cdot7H_2O$, 0.001% $MnSO_4\cdot4H_2O$; pH 6.5] for the phytase production significantly induced its enzyme activity in comparison with other carbon sources tested.