• Applied Chemistry for Engineering
• /
• v.29 no.6
• /
• pp.726-733
• /
• 2018

The rice's waste byproduct is known as a rice bran and produced annually about 400,000 to 600,000 tons. Most of the rice bran are used as a livestock feed or waste disposal, and needed to be used to produce high-added substances, such as bioactive materials. In this study, extraction conditions of the ultrasound-assisted extraction (UAE) of the rice bran were optimized using a statistically-based optimization. The influence of extraction variables including the extraction time ($X_1$), extraction temperature ($X_2$) and ethanol concentration ($X_3$) were investigated using the response surface methodology in order to determine optimum extraction conditions which maximize total phenolic compounds (TPC), total flavonoid compounds (TFC) and electron donating abilities (EDA). The optimal UAE from rice bran was achieved under the extraction temperature of $94.9^{\circ}C$, extraction time of 41.6 minute and ethanol concentration of 74.0% (v/v) with maximum yields of TPC 2.78 mg GAE/g DM, TFC 1.63 mg QE/g DM and EDA 42.86%. The UAE process shows its potential to the extraction of bioactive and antioxidant compounds from rice bran in a short extraction time and low temperature. Also, it is proposed that rice bran could be considered as food additives and cosmeceutical products.

• Microbiology and Biotechnology Letters
• /
• v.37 no.2
• /
• pp.118-124
• /
• 2009

Esterase EM2L8 gene isolated from deep sea sediment was expressed in Escherichia coli BL21 (DE3) and the esterase activity of the cell-free extract was assayed using p-nitrophenyl butyrate-spectrophotometric method. Its optimum temperature was $40-45^{\circ}C$ and 45% activity of the maximum activity was retained at $15^{\circ}C$. The activation energy at $15-45^{\circ}C$ was calculated to be 4.9 kcal/mol showing that esterase EM2L8 was a typical cold-adapted enzyme. Enzyme activity was maintained for 6 h and 4 weeks at $30^{\circ}C$ and $4^{\circ}C$, respectively. When each ethanol, methanol, and acetone was added to the reaction mixture to 15% concentration, enzyme activity was maintained. In the case of DMSO, enzyme activity was kept up to 40% concentration. (S)-4-Chloro-3-hydroxy butyric acid is a chiral intermediate for the synthesis of Atorvastatin, a hyperlipemia drug. When esterase EM2L8 (40 U) was added to buffer solution (1.2 mL, pH 9.0) containing ethyl-(R,S)-4-chloro-3-hydroxybutyrate (38 mM), it was hydrolyzed into 4-chloro-3-hydroxy butyric acid with a rate of $6.8\;{\mu}mole/h$. The enzyme hydrolyzed (S)-substrate more rapidly than (R)-substrate. When conversion yield was 80%, e.e.s value was 40%. When DMSO was added, hydrolysis rate increased to $10.4\;{\mu}mole/h$. The plots of conversion yield vs e.e.s in the presence or absence of DMSO were almost same, implying that the reaction enantioselectivity was not changed by the addition of DMSO. Taken together, esterase EM2L8 had high activity and stability at low temperatures as well as in various organic solvents/aqueous solutions. These properties suggested that it could be used as a biocatalyst in the synthesis of useful pharmaceuticals.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.10
• /
• pp.1378-1387
• /
• 2012

To investigate the pharmacological activity of chaga mushroom (Inonotus obliquus) on extraction conditions, chaga was extracted using water (reflux at $50^{\circ}C$, decoction over $90^{\circ}C$, pressure at $121^{\circ}C$) or ethanol (reflux at 50, 70, or $90^{\circ}C$). When water extract was further fractionated into crude polysaccharide (IO-CP), yields of IO-CP (4.8~16.8%) were higher than those of ethanolic extracts (IO-E, 1.9~2.7%) at increased temperature. For antioxidant activity, crude polysaccharide (IO-CP-121) obtained by pressurized extraction showed the highest polyphenolic and flavonoid contents (35.10 mg TAE/g and 18.48 mg QE/g, respectively) as well as DPPH and ABTS free radical scavenging activities (26.08 and 27.99 mg AEAC/100 mg, respectively). Meanwhile, IO-CP-D (decoction) and IO-CP-50 (reflux) had more potent mitogenic effects (2.10- and 1.95-fold of saline control at 100 ${\mu}g/mL$) as well as intestinal immune system modulating activities (6.30- and 5.74-fold) compared to IO-CP-121, whereas ethanolic extracts showed no activity. Although no IO-CP showed cytotoxicity against RAW 264.7 cells at 0.1 mg/mL, IO-CP-121 significantly inhibited TNF-${\alpha}$ and NO production as pro-inflammatory factors in LPS-stimulated RAW 264.7 cells (29.2 and 63.5%, respectively). Ethanolic extracts also showed no cytotoxicity at 0.1 mg/mL, whereas inhibition of TNF-${\alpha}$ and NO production was significantly low compared to that of IO-CP-121. In addition, active IO-CP-D was further fractionated into an unadsorbed (IO-CP-I) and seven adsorbed fractions (IO-CP-II~VIII) by DEAE-Sepharose CL-6B column chromatography in order to isolate immunostimulating polysaccharide. IO-CP-II showed the most potent mitogenic effect and macrophage stimulating activity (4.51- and 1.64-fold, respectively). IO-CP-II mainly contained neutral sugars (61.86%) in addition to a small amount of uronic acid (2.96%), and component sugar analysis showed that IO-CP-II consisted mainly of Glc, Gal, and Man (molar ratio of 1.00:0.55:0.31). Therefore, extraction conditions affect the physiological activity of chaga, and immunostimulating polysaccharide fractionated from chaga by decoction is composed mainly of neutral sugars.

• Journal of Life Science
• /
• v.21 no.1
• /
• pp.119-126
• /
• 2011

There is a growing recognition of the significance of $H_2S$ as a biological signaling molecule involved in vascular and nervous system functions. In mammals, two enzymes in the transsulfuration pathway, cystathionine ${\beta}$-synthase (CBS) and cystathionine ${\gamma}$-lyase (CGL), are believed to be chiefly responsible for $H_2S$ biogenesis. Genetic inborn error of CGL leads to human genetic disease, cystathioninuria, by accumulating cystathionine in the body. This disease is secondarily associated with a wide range of diseases including diabetes insipidus and Down's syndrome. Although the human CGL (hCGL) overexpression is essential for the investigation of its function, structure, reaction specificity, substrate specificity, and protein-protein interactions, there is no clear report concerning optimum overexpression conditions. In this study, we report a detailed analysis of the overexpression conditions of the hCGL using a bacterial system. Maximum overexpression was obtained in conditions of low culture temperature after inducer addition, performing low aeration during overexpression, and using a low concentration inducer (0.1 mM, IPTG) for induction. Expressed hCGL was purified by His-tag affinity column chromatography and confirmed by Western blot using hCGL antibody and enzyme activity analysis. We also report that the His tag with TEV site attached protein exhibits 76% activity for ${\alpha}-{\gamma}$ elimination reaction with L-cystathionine and 88% for ${\alpha}-{\beta}$ elimination reaction with L-cysteine compared to those of wild type hCGL, respectively. His tag with TEV site attached protein also exhibits a 420 nm absorption maximum, which is attributed to the binding cofactor, pyridoxal 5'-phosphate (PLP).

• Korean Journal of Environmental Agriculture
• /
• v.17 no.3
• /
• pp.260-267
• /
• 1998

This experiment used the enclosed bench-scale reactors of 242 liters was conducted to obtain basic data on temporal and spatial variations in temperature, oxygen and moisture content, which were important factors of biological activities, during composting of mixture of dairy manure and rice straw. The reactors with thermocouples, oxygen sensor and datalogger were aerated at four different rates of 0.09, 0.18, 0.90 and 1.79 l $min^{-1}kg$ dry $solids^{-1}$. The higher aeration rates were, the faster the rates of increase and decrease in composting temperature were in both of initial and turnover stage, and the smaller the temperature difference between exhaust air and composting materials. Composting temperature of initial stage increased suddenly in all aeration rates, then stationary phase of temperature in materials and exhaust air showed at $50{\sim}53^{\circ}C$ for 5 hours and at $45^{\circ}C$ between 5 and 15 hours, respectively. In initial stage the maximum temperature was decreased with increasing aeration rates but in the stage after turnover it was the opposite except for 1.79 l $min^{-1}kg^{-1}$. Time arrived at the maximum temperature of composting materials was later in low-aeration rates than high-aeration rates at both stages. Time maintained high-temperature more than $45^{\circ}C$ was rapidly decreased with increasing aeration rates. In initial stage of composting maintaining time of $65^{\circ}C$ or more was the longest in the treatments of 0.09 and 0.18 l $min^{-1}kg{-1}$, while those of $55{\sim}65^{\circ}C$ and $45{\sim}55^{\circ}C$ was in 0.90 and 1.79 l $min^{-1}kg{-1}$, respectively. The minimum oxygen content and the maximum oxygen consumption rate in exhaust air through composting materials showed the increased trends with increasing aeration rates. In initial stage the minimum oxygen content was ranged from 0.9% to 7.4% for 32 to 59.5 hours and the maximum oxygen consumption rate was $1.89{\sim}6.48$ $gh^{-1}kgVS^{-1}$. In the stage after turnover their levels were $2.1{\sim}19.9%$ and $1.76{\sim}3.49 %$g/h-㎏ VS, respectively, for 16 to 49.5 hours.

• Atmosphere
• /
• v.24 no.3
• /
• pp.283-301
• /
• 2014

In 2010, only 14 tropical cyclones (TCs) were generated over the western North Pacific (WNP), which was the smallest since 1951. This study summarizes characteristics of TCs generated in 2010 over the WNP and investigates the causes of the record-breaking TC genesis. A long-term variation of TC activity in the WNP and verification of official track forecast in 2010 are also examined. Monthly tropical sea surface temperature (SST) anomaly data reveal that El Ni$\tilde{n}$o/Southern Oscillation (ENSO) event in 2010 was shifted from El Ni$\tilde{n}$o to La Ni$\tilde{n}$a in June and the La Ni$\tilde{n}$a event was strong and continued to the end of the year. We found that these tropical environments leaded to unfavorable conditions for TC formation at main TC development area prior to May and at tropics east of $140^{\circ}E$ during summer mostly due to low SST, weak convection, and strong vertical wind shear in those areas. The similar ENSO event (in shifting time and La Ni$\tilde{n}$a intensity) also occurred in 1998, which was the second smallest TC genesis year (16 TCs) since 1951. The common point of the two years suggests that the ENSO episode shifting from El Ni$\tilde{n}$o to strong La Ni$\tilde{n}$a in summer leads to extremely low TC genesis during La Ni$\tilde{n}$a although more samples are needed for confidence. In 2010, three TCs, DIANMU (1004), KOMPASU (1007) and MALOU (1009), influenced the Korean Peninsula (KP) in spite of low total TC genesis. These TCs were all generated at high latitude above $20^{\circ}N$ and arrived over the KP in short time. Among them, KOMPASU (1007) brought the most serious damage to the KP due to strong wind. For 14 TCs in 2010, mean official track forecast error of the Korea Meteorological Administration (KMA) for 48 hours was 215 km, which was the highest among other foreign agencies although the errors are generally decreasing for last 10 years, suggesting that more efforts are needed to improve the forecast skill.

• Korean Journal of Food Science and Technology
• /
• v.31 no.4
• /
• pp.1050-1056
• /
• 1999

The effect of ${\gamma}-irradiation$ was investigated on salted and fermented squid, squid jeotkal. Squid jeotkal was prepared with salt concentrations of 5%, 10% and 20% and was fermented at $15^{\circ}C$ and $25^{\circ}C$ after ${\gamma}-irradiation$ with doses of 0, 2.5, 5 and 10 kGy, respectively. Proximate composition, salinity, water activity (Aw), pH, total bacteria and sensory evaluation were examined during fermentation periods. Results showed that ${\gamma}-irradiation$ had no effect on proximate composition, salinity and Aw compared with non-irradiated squid jeotkal. However, pH and total bacteria, as well as sensory evaluation, were changed variously with processing conditions such as NaCl concentration, irradiation dose and fermentation temperature. The results of total bacteria and sensory evaluation showed that squid jeotkal with NaCl concentration of 10% and an irradiation dose of 10 kGy maintained high quality for 30 days at $15^{\circ}C$. Therefore, it was considered that ${\gamma}-irradiation$ was effective in processing low-salted squid jeotkal and extending its shelf-life without adding any food additives.

• Journal of Life Science
• /
• v.25 no.12
• /
• pp.1393-1398
• /
• 2015

In this study, we investigated the extraction condition of alginate from Laminaria japonica, the enzymatic degradation of the extracted alginate, and the inhibitory activity of the degraded alginate on the differentiation of 3T3-L1 preadipocytes. The optimal conditions for the efficient extraction, precipitation, and recovery of alginate from the brown seaweed L. japonica were 1% for Na₂CO₃ concentration, 80℃ for extraction temperature, and ethanol for precipitation solvent. In the enzymatic reaction for the production of low-molecular-weight alginate (LMWA) by using alginate lyase from Flavobacterium sp., the initial concentration of Laminaria alginate was 3%. The low-molecular-weight degree from alginate was independent with the enzyme concentration, and the optimal concentration of alginate lyase was found to be 5 unit/ml. Through the enzymatic reaction with 5 unit/ml of alginate lyase at 37℃ for 3 hr, the viscosity and molecular weight of LMWA were 4.5 cp and 307 kDa, respectively. Treatment with LMWA significantly suppressed the accumulation of lipid droplet and triglyceride in 3T3-L1 preadipocytes with a dose-dependent manner. Therefore, it seems that LMWA treatment could inhibit the differentiation of 3T3-L1 preadipocytes. These results indicate that LMWA or the degraded alginate produced by alginate lyase enzyme can be useful for the development of anti-obesity biosubstances.

• Korean Journal of Medicinal Crop Science
• /
• v.12 no.4
• /
• pp.321-327
• /
• 2004

Cortex of Ulmus davidiana var. japonica N. and Hemipteleae davidii P. have been used without classification according to countries as oriental medicine for treatment of various disorders. This study was conducted to elucidate the difference in antioxidant activity and total phenol content of these medicinal materials. Root cortex and trunk cortex of two medicinal plants were extracted with 80% ethanol $(at\;85^{\circ}C)$ and water (at room temperature), respectively. All of the extracts at $200{\sim}5\;{\mu}g/ml$, showed more effective scavenging activity on superoxide radical than ascorbic acid, and 80% ethanol and water extracts of Ulmus root cortex (URC) was more effective. Scavenging activities on DPPH radical of 80% ethanol extracts from URC and Ulmus trunk cortex (UTC) at 10 ${\mu}g/ml$, (41.4, 35.6%) were higher than those of the other six extracts and ${\alpha}-tocopherol\;(2.3{\sim}24.0%)$. Inhibitory activities on human low density lipoprotein (LDL) oxidation of 80% ethanol extracts from UTC and URC (84.3, 81.7%) at $10\;{\mu}g/ml\;(31.3{\sim}78.2%)$ were higher than those of the other six extracts and ${\alpha}-tocopherol$. However, antioxidant activities on linoleic acid peroxidation of all of the extracts were relatively lower than that ${\alpha}-tocopherol$. Total phenol content of 80% ethanol extract from URC was the highest value as 50.8% and that of water extract from HRC was the lowest as 5.6% among the extracts. From these results, it is suggested that Ulmus root cortex was the most effective in antioxidant activity.

• Microbiology and Biotechnology Letters
• /
• v.26 no.5
• /
• pp.456-464
• /
• 1998

For the standardization and quality improvement of traditional Korean Nuruk, 10 strains of fungi, which were isolated from Nuruks and showed good productivity of the saccharogenic and dextrinogenic enzymes, acid and flavor, were selected and their enzymological characteristics and identification were carried out. Aspergillus spp. and Rhizopus sp. showed a high liquefying activity without regard to cultivation time, whereas the majority of strains except for Rhizopus sp. had decreasing saccharifying activity in proportion to the increase in cultivation time. Aspergillus spp. No.17-2, No.17-6 and Rhizopus sp. No.18-1 showed high liquefying and saccharifying activity after 15 and 30 day cultivation. The optimum temperature of most of these saccharogenic and dextrinogenic enzymes was from 40$^{\circ}C$ to 60$^{\circ}C$, and their optimum pH was extensive between pH 3 and pH 11. But Penicillium spp.(2 strains) and Rhizopus sp. showed low activity under the alkalic and acidic conditions. Among these isolated strains, 5 strains which had shown the high productivity of materials were identified as Aspergillus oryzae NR3-6 and Aspergillus oryzae NR17-6, Aspergillus penicilloides NR12-1, Penicillium expansum NR7-7 and Rhizopus oryzee NRl8-1, respectively. Five kinds of mixed culture were carried out and all of them showed a better productivity of saccharogenic and dextrinogenic enzymes than single culture. These results indicate that it is possible to make traditional Korean liquors of good quality by using these fungi.