• Journal of Dairy Science and Biotechnology
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• v.30 no.1
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• pp.45-53
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• 2012

Lactobacillus acidophilus isolated from the feces of a 7-day-old breast-fed infant was characterized to examine the scope of its commercial use. Forty-three Lactobacillus strains, which could grow at pH 5.5, were isolated. From these Lactobacillus isolates, 14 Lactobacillus strains were selected, which demonstrated more than 80% viability and homofermentative lactic fermentation. Finally, 9 L. acidophilus strains (NB 201~NB 209) were identified as candidate strains based upon biochemical properties, carbohydrate utilization, and cellular fatty acid composition. L. acidophilus isolates demonstrated a survival rate of more than 80% when exposed to pH 2.5 for 2 h. In particular, L. acidophilus NB 204 showed a strong acid tolerance, with a 71% survival rate even at pH 2.0. L. acidophilus isolates also manifested high bile acid tolerance; more than 87% of the cells survived on agar containing 1% bile extract, except for L. acidophilus NB 206, which showed a 73% survival rate. All L. acidophilus isolates were confirmed to have proteolytic activity; L. acidophilus NB 204 and NB 209 yielded higher levels of TCA-soluble peptides and free amino acids. The ${\beta}$-galactosidase activity of the L. acidophilus isolates was in the range of 1.97~2.45 units/mL.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.6
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• pp.818-823
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• 2012

Tall fescue (Festuca arundinacea Schreb.) is an important cool season forage plant that is not well suited to extreme heat, salts, or heavy metals. To develop transgenic tall fescue plants with enhanced tolerance to abiotic stress, we introduced an alfalfa Hsp23 gene expression vector construct through Agrobacterium-mediated transformation. Integration and expression of the transgene were confirmed by polymerase chain reaction, northern blot, and western blot analyses. Under normal growth conditions, there was no significant difference in the growth of the transgenic plants and the non-transgenic controls. However, when exposed to various stresses such as salt or arsenic, transgenic plants showed a significantly lower accumulation of hydrogen peroxide and thiobarbituric acid reactive substances than control plants. The reduced accumulation of thiobarbituric acid reactive substances indicates that the transgenic plants possessed a more efficient reactive oxygen species-scavenging system. We speculate that the high levels of MsHsp23 proteins in the transgenic plants protect leaves from oxidative damage through chaperon and antioxidant activities. These results suggest that MsHsp23 confers abiotic stress tolerance in transgenic tall fescue and may be useful in developing stress tolerance in other crops.

• Korean Journal of Food Science and Technology
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• v.17 no.3
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• pp.192-196
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• 1985

Eight strains of Lactobacilli(a, b, b', c, d, e, f and g) were isolated from seven Korean liquid-yogurts(A, B, C, D, E, F and G), and identification and tolerance-test to digestive fluids were carried out. Isolate a from yogurt A and isolate a from yogurt E were identified as L. casei, isolate b from yogurt B as L. acidophilus, isolate d from yogurt D as L. bulgaricus, isolate f from yogurt F as L. helveticus, and isolate b' from yogurt B, isolate c from yogurt C and isolate g from yogurt G as L. jugurti, respectively. Isolate f(L. helveticus) and c(L. jugurti) showed high tolerance to artificial gastric juice but didn't to bile acid. Isolate b(L. acidophilus), a(L. casei), and e(L. casei) showed high tolerance to both artificial gastric juice and bile acid, but isolate d(L. bulgaricus), b'(L. jurgurti) and g(L. jugurti) did not.

• Journal of Microbiology and Biotechnology
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• v.29 no.7
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• pp.1124-1136
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• 2019

Salinity is one of the major abiotic stresses that cause reduction of plant growth and crop productivity. It has been reported that plant growth-promoting bacteria (PGPB) could confer abiotic stress tolerance to plants. In a previous study, we screened bacterial strains capable of enhancing plant health under abiotic stresses and identified these strains based on 16s rRNA sequencing analysis. In this study, we investigated the effects of two selected strains, Bacillus aryabhattai H19-1 and B. mesonae H20-5, on responses of tomato plants against salinity stress. As a result, they alleviated decrease in plant growth and chlorophyll content; only strain H19-1 increased carotenoid content compared to that in untreated plants under salinity stress. Strains H19-1 and H20-5 significantly decreased electrolyte leakage, whereas they increased $Ca^{2+}$ content compared to that in the untreated control. Our results also indicated that H20-5-treated plants accumulated significantly higher levels of proline, abscisic acid (ABA), and antioxidant enzyme activities compared to untreated and H19-1-treated plants during salinity stress. Moreover, strain H20-5 upregulated 9-cisepoxycarotenoid dioxygenase 1 (NCED1) and abscisic acid-response element-binding proteins 1 (AREB1) genes, otherwise strain H19-1 downregulated AREB1 in tomato plants after the salinity challenge. These findings demonstrated that strains H19-1 and H20-5 induced ABA-independent and -dependent salinity tolerance, respectively, in tomato plants, therefore these strains can be used as effective bio-fertilizers for sustainable agriculture.

• Journal of Environmental Science International
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• v.21 no.1
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• pp.113-123
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• 2012

A unit emission reduction of nitrous oxide ($N_2O$) from anthropogenic sources is equivalent to a 310-unit $CO_2$ emission reduction because the $N_2O$ has the global warming potential (GWP) of 310. This greatly promoted very active development and commercialization of catalysts to control $N_2O$ emissions from large-scale stationary sources, representatively nitric acid production plants, and numerous catalytic systems have been proposed for the $N_2O$ reduction to date and here designated to Options A to C with respect to in-duct-application scenarios. Whether or not these Options are suitable for $N_2O$ emissions control in nitric acid industries is primarily determined by positions of them being operated in nitric acid plants, which is mainly due to the difference in gas temperatures, compositions and pressures. The Option A being installed in the $NH_3$ oxidation reactor requires catalysts that have very strong thermal stability and high selectivity, while the Option B technologies are operated between the $NO_2$ absorption column and the gas expander and catalysts with medium thermal stability, good water tolerance and strong hydrothermal stability are applicable for this option. Catalysts for the Option C, that is positioned after the gas expander thereby having the lowest gas temperatures and pressure, should possess high de$N_2O$ performance and excellent water tolerance under such conditions. Consequently, each de$N_2O$ technology has different opportunities in nitric acid production plants and the best solution needs to be chosen considering the process requirements.

• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.924-927
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• 2003

This study was conducted to investigate the application of bifidobacteria on kimchi. Among several Bifidobacterium species, we selected Bifidobacterium lactis (DSM 10140), which is resistant to oxygen, acid and salt. Bifidobacterium lactis was cultured in a supplemented deMan, Rogosa and Sharpe (SMRS) medium under aerobic conditions. Its acid-tolerance and salt-tolerance were pH 3.0 and 3.5% (NaCl), respectively. The viability of Bifidobacterium lactis added to kimchi was confirmed by PCR, using specific primers on Bifidobacterium lactis. In sensory evaluation, kimchi containing Bifidobacterium lactis showed similar scores in overall acceptability with the control kimchi. Consequently, these results showed that it would be possible to prepare functional kimchi using Bifidobacterium.

• Journal of Microbiology and Biotechnology
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• v.24 no.5
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• pp.683-689
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• 2014

Since $CO_2$ concentrations in industrial flue gases are usually 10%-20%, one of the prerequisites for efficient $CO_2$ removal by algae is the level of tolerance of microalgal species to exposure to high concentrations of $CO_2$. A newly isolated microalgal strain, Chlorella sp. MRA-1, could retain growth with high concentrations of $CO_2$ up to 15%. The highest lipid productivity for Chlorella sp. MRA-1 was 0.118 g/l/day with a 5% $CO_2$ concentration. Octadecenoic acid and hexadecanoic acid, the main components of biodiesel, accounted for 70% of the total fatty acids. A lipid content of 52% of dry cell weight was achieved with limited amounts of nitrogen. Chlorella sp. MRA-1 seems to be an ideal candidate for biodiesel production when cultured with high concentrations of $CO_2$.

• Korean journal of food and cookery science
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• v.20 no.6 s.84
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• pp.658-666
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• 2004

In order to develop and commercialize high quality frozen soy yogurt, the effects of industrial proteases and commercial mixed cultures were examined on the functional properties and the sensory attributes of frozen soy yogurt. For quality improvement, soy protein isolates were primarily hydrolyzed by either Flavourzyme or Neurtrase, industrial Proteases, to reduce the beany flavor and increase the functional properties of the protein. The viable cell count of lactic acid bacteria was higher in the soy protein hydrolysates than whenuntreated. ABT-5 (L. acidophilus, Bifidobacterium lactis, and S. thermophilus) resulted in higher acid tolerance, bile acid tolerance and melt-down percent values than those with YC-X11 (Lactobacillus bulgaricus and Streptococci thermophilus). The overrun of frozen soy yogurt was improved by both Flavourzyme $(193.3\%)$ and Neurtrase $(156.7\%)$ treatments. With regard to thesensory characteristics, Flavourzyme improved the beany flavor, astringency taste, mouth feel and overall quality of frozen soy yogurts fermented with ABT-5. Further studies onproduct formulation will be needed to commercialize the frozen soy yogurt for the market.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1345-1353
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• 2007

The effect of salicylic acid(SA) on antioxidant system and protective mechanisms against UV-B induced oxidative stress was investigated in cucumber(Cucumis sativus L.) leaves. UV-B radiation and SA were applied separately or in combination to first leaves of cucumber seedlings, and dry matter accumulation, lipid peroxidation and activities of antioxidant enzymes were measured in both dose and time-dependant manner. UV-B exposure showed reduced levels of fresh weight and dry matter production, whereas SA treatment significantly increased them. SA noticeably recovered the UV-B induced inhibition of biomass production. UV-B stress also affected lipid peroxidation and antioxidant enzyme defense system. Malondialdehyde(MDA), a product of lipid peroxidation, was greatly increased under UV-B stress, showing a significant enhancement of a secondary metabolites, which may have antioxidative properties in cucumber leaves exposed to UV-B radiation. Combined application of UV-B and SA caused a moderate increase in lipid peroxidation. These results suggest that SA may mediate protection against oxidative stress. UV-B exposure significantly increased SOD, APX, and GR activity compared with untreated control plants. Those plants treated with 1.0 mM SA showed a similar pattern of changes in activities of antioxidant enzymes. SA-mediated induction of antioxidant enzyme activity may involve a protective accumulation of $H_2O_2$ against UV-B stress. Moreover, their activities were stimulated with a greater increase by UV-B+SA treatment. The UV-B+SA plants always presented higher values than UV-B and SA plants, considering the adverse effects of UV-B on the antioxidant cell system. ABA and JA, second messengers in signaling in response to stresses, showed similar mode of action in UV-B stress, supporting that they may be important in acquired stress tolerance. Based on these results, it can be suggested that SA may participates in the induction of protective mechanisms involved in tolerance to UV-B induced oxidative stress.

• Journal of Microbiology and Biotechnology
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• v.10 no.2
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• pp.147-153
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• 2000

This study was conducted to compare probiotic activities and physiological functions of Bifidobacterium longum Mk-G7 with weveral commercial and type strains of bifidobacteria. bif. longum MK-G7 showed the highest acid tolerance against HCl and acetic acid, whereas bif. infantis Y-1 showed the lowest acid tolerance and more than 4 log cycles of viable cell count decreased due to acid injuty. Viable cell counts of bifidobacteria strains decreased more than 1.5 log cycles owing to oxygen toxicity, with the exception of Bif. longum MK-G7, Bif. infantis Y-2, Bif. longum Y-3, Bif. longum Y-6, and Bif. longum RD-13 showed the highest bile tolerance, whereas Bif. longum MK-G7 showed a medium level of bile tolerance. Only Bif. longum MK-G7 howed much higher antibiotic resistance against both tetracycline and penicillin-G in the MIC(minimum inhibitory concentration) level of 24.8 mg/I and 0.52mg/I, respectively. Bif longum Y-6, and Bif. bifidum ATCC 29539 showed more than 80% of anti-mutagenicity against NQO(4-nitroquinolinel-oxide). Since the production of cytokines such as $TNF(tumor necrosis factor)-{\alpha}$ and IL (interleukin)-6, and NO(nitric oxide) in the macrophage cell line Raw 264.7 cells increased as Bif. longum MK-G7 cell concentration increased, ti was suggested that Bif. longum MK-G7 is able to enhance immunopotentiating activity in vitro. When freeze-dred Bif. longum MK-G7 was administered to mice at the dose of 1,2,4, and 6 g/kg of body weight, all of the mice survived in all feeding groups, proving the GRAS(generally recognized as safe) status of Bif. longum MK-G7. When fermented milk containing Bif. longum MK-G7 was administered to human volunteers, viable cell count of total bifidobacteria and anaerobes in the feces increased up to 0.5 log cycles more than before the administration. In particular, Bif. logum MK-G7 ingibited the growth of Bacteroides at the level of 1.0-1.5 log cycles.