• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.121-125
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• 2002

Rhodococcus rhodochrous IGTSS (ATCC 5396S) can break organo sulfur compounds such as dibenzothiophene. Since the environment for biodesulfurization process is invariably hydrophobic, parameters in hydrophobic systems should be examined. For the model oil, hexadecane-containing 5.43mM dibenzothiophene, the volumetric desulfurization rate was decreased with the oil-to-aqueous phase ratio up to 50%. The rate declined sharply after 48h because the cell activity, which is refreshed by medium exchange, was lost. To supply the exhausted nutrients, medium exchange was performed. At 30% oil phase, most of DBT was removed by medium exchange on 48h, and the rate was 2.03mg $DBT_{removed}/L_{dispersion}-hr.$ At 50% oil phase, medium exchange on 60h was performed and the rate was 1.79mg $DBT_{removed}/L_{dispersion}-hr.$ The 300mL flask system was scaled up to a 5-L bioreactor system. On 60 h, a medium exchange was performed and the rate was 5.28mg $DBT_{removed}/L_{dispersion}-hr.$ and all of DBT was removed. It means that we can use the biodesulfurization process even 10 the high oil-to-water phase by some appropriate methods such as controlled feeding of key nutrients and the dilution or removal of some toxic metabolites by continuous reactor.

• Solar Energy
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• v.20 no.4
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• pp.25-30
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• 2000

The present study has been conducted to offer an geometrically optimal structure of a storage tank for a regenerator. In this paper, three kinds of baffle plates supposed to increase the regeneration rate and classified as "Type A($L^*$=0.25, 80(L)$\times$300(W)$\times$50 (H) [mm])", "Type B($L^*$=0.5, 150(L)$\times$300(W)$\times$50 (H) [mm])", and "Type C($L^*$=0.75, 230(L)$\times$300(W)$\times$50(H) [mm])" were suggested and tested. They were placed between the vertical C-C layers in the tank. Solution temperature and concentration were used to evaluate the regeneration rate. As a result, the regeneration rate was better in "Type C".

• Journal of Microbiology and Biotechnology
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• v.22 no.6
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• pp.826-831
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• 2012

Acarbose, a pseudo-oligosaccharide, is widely used clinically in therapies for non-insulin-dependent diabetes. In the present study, S-adenosylmethionine (SAM) was added to selected media in order to investigate its effect on acarbose fermentation by Actinoplanes utahensis ZJB-08196. Acarbose titer was seen to increase markedly when concentrations of SAM were added over a period of time. The effects of glucose and maltose on the production of acarbose were investigated in both batch and fed-batch fermentation. Optimal acarbose production was observed at relatively low glucose levels and high maltose levels. Based on these results, a further fed-batch experiment was designed so as to enhance the production of acarbose. Fed-batch fermentation was carried out at an initial glucose level of 10 g/l and an initial maltose level of 60 g/l. Then, 12 h post inoculation, 100 ${\mu}mol/l$ SAM was added. In addition, 8 g/l of glucose was added every 24 h, and 20 g/l of maltose was added at 96 h. By way of this novel feeding strategy, the maximum titer of acarbose achieved was 6,113 mg/l at 192 h. To our knowledge, the production level of acarbose achieved in this study is the highest ever reported.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.2
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• pp.235-240
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• 2000

Inhibitory effects of cockle extracts on carcinogen-induced cytotoxicity in C3H/10T1/2 cells were studied. Soup (62$\mu\textrm{g}$/mL), solubility (28$\mu\textrm{g}$/mL) and liposolubility (9 $\mu\textrm{g}$/mL) of the cockle inhibited 3-methyl-cholanthrene(MCA)-induced cytotoxicity in C3H/10T1/2 cells by 53 and 94%, respectively. These results suggest that the extracts cockle might have anticarcinogen-induced cytotoxicity of C3H/10T1/2 cells. The effects of cockle extracts on the immune response related to its antitumor activity in vitro and in vivo were investigated. The cockle extracts showed a direct cytotoxic effect on sarcoma-180 cells, tumor cells in vitro. Soup (0.49 mg/mL), solubility (0.11 mg/mL) and liposolubiliy (0.05 mg/mL) of the cockle markedly decreased the total numbers of sarcoma-180 cells, but not their viability. The phagocytic acitivity of peritoneal macrophage of mice was significantly augmented by these extracts of the cockle compared with that of control in vivo. These extracts also raised the phagocuytic index, indicating that the number of phagocytize dmicrobes per macrophage increased. Thus, cockle extracts might show a antitumor activity by enhancing the phagocytic cell activities.

• Journal of Microbiology and Biotechnology
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• v.33 no.9
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• pp.1189-1196
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• 2023

This study proposed to demonstrate the neuroprotective effects of heat-killed Levilactobacillus brevis KU15152. Heat-killed L. brevis KU15152 showed antioxidant activity similar to that of Lacticaseibacillus rhamnosus GG, in terms of radical scavenging activity. To evaluate the neuroprotective effects, conditioned medium (CM) obtained by incubating heat-killed bacteria in intestinal cells (HT-29) was used through gut-brain axis. CM from L. brevis KU15152 protected neuroblastoma cells (SH-SY5Y) against H₂O₂-induced oxidative stress. Pretreatment with CM significantly alleviated the morphological changes induced by H₂O₂. Heat-killed L. brevis KU15152 showed an increased brain-derived neurotrophic factor (BDNF) expression in HT-29 cells. L. brevis KU15152-CM remarkably downregulated the Bax/Bcl-2 ratio, while upregulating the expression of BDNF and tyrosine hydroxylase (TH) in SH-SY5Y cells. Furthermore, L. brevis KU15152-CM reduced caspase-3 activity following H₂O₂ treatment. In conclusion, L. brevis KU15152 can be potentially used as food materials to avoid neurodegenerative diseases.

• Journal of Food Hygiene and Safety
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• v.35 no.1
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• pp.83-92
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• 2020

This study investigated the optimal conditions of enzymatic reaction for production of isomaltooligosaccharides (IMO) using rice flour. To manufacture IMO, commercial enzymes (Termamyl 2X, Maltogenase L, Promozyme D2, Fungamyl 800L and Transglucosidase L) were used. The sugar composition and amount of IMO were examined by HPLC with charged aerosol detector (HPLC-CAD) in each manufacturing process. Liquefaction reaction was performed according to different Termamyl 2X concentrations (0.025%, 0.05%, 0.075%, 0.1%) and reaction times (1 h, 2 h). As a result, the reducing sugar content was the highest at 138.26 g/L when 0.075% Termamyl 2X was added for 2 hours. In order to optimize simultaneous saccharification and transglucosylation, experiments on enzyme selection, enzyme concentration and enzyme reaction time were conducted. Reaction with 0.0015% Maltogenase L, 0.05-0.1% Promozyme D2 and 0.1% Tansglucosidase L was effective in decreasing glucose content and increasing content of IMO with a high degree of polymerization. A change in sugar content was observed every 6 hours to determine the optimal reaction time, and the highest IMO was produced after 36 hours of reaction (75.36 g/L). The IMO prepared under optimal conditions showed isomaltose, 35.11 g/L; panose, 11.97 g/L; isomaltotriose, 19.95 g/L; isomaltotetraose, 7.46 g/L; isomaltopentaose, 1.05 g/L at 18 brix and the ratio of IMO in the total sugar was 56.37%.

• Honam Mathematical Journal
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• v.44 no.1
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• pp.135-145
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• 2022

This paper aims to investigate characterizations on parameters k₁, k₂, k₃, k₄, k₅, l₁, l₂, l₃, and l₄ to find relation between the class of 𝓗(k, l, m, n, o) hypergeometric functions defined by $$5_F_4\[{\array{k_1,\;k_2,\;k_3,\;k_4,\;k_5\\l_1,\;l_2,\;l_3,\;l_4}}\;:\;z\]=\sum\limits_{n=2}^{\infty}\frac{(k_1)_n(k_2)_n(k_3)_n(k_4)_n(k_5)_n}{(l_1)_n(l_2)_n(l_3)_n(l_4)_n(1)_n}z^n$$. We need to find k, l, m and n that lead to the necessary and sufficient condition for the function zF([W]), G = z(2 - F([W])) and $H_1[W]=z^2{\frac{d}{dz}}(ln(z)-h(z))$ to be in 𝓢^*(2^-r), r is a positive integer in the open unit disc 𝒟 = {z : |z| < 1, z ∈ ℂ} with $$h(z)=\sum\limits_{n=0}^{\infty}\frac{(k)_n(l)_n(m)_n(n)_n(1+\frac{k}{2})_n}{(\frac{k}{2})_n(1+k-l)_n(1+k-m)_n(1+k-n)_nn(1)_n}z^n$$ and $$[W]=\[{\array{k,\;1+{\frac{k}{2}},\;l,\;m,\;n\\{\frac{k}{2}},\;1+k-l,\;1+k-m,\;1+k-n}}\;:\;z\]$$.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.3
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• pp.21-29
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• 1998

The ozone/GAC process, sometimes termed BAC(Biological Activated Carbon) appeared to be effective for the removal of soluble organic matters in the drinking water Chabrol is a simple model for the simulation like as the variation of HPC and BDOC in the BAC tower. This study were carried out to calibrate of HPC and BDOC and to evaluate $H_1$ and $H_2$ of ozone-treated water with Chabrol model. BDOC values of the ozone-treated water and BAC effluent are analyzed using method of Levi and Joret. As the ozone-treated water and BAC Effluent are incubated, the HPC are increased up to 0.24 mgC/l and 0.09 mgC/l respectively. $H_1$ and $H_2$ of the ozone-treated water is 0.3 mgC/l and 0.349 mgC/l respectively and Chabrol model for BAC tower can be calibrated.

• Communications of the Korean Mathematical Society
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• v.12 no.3
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• pp.597-602
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• 1997

Let H be a separable complex Hilbert space and L(H) be the *-algebra of all bounded linear operators on H. For $T \in L(H)$, we construct a pair of semi-positive definite operators $$ $\mid$T$\mid$_r = (T^*T)^{\frac{1}{2}} and $\mid$T$\mid$_l = (TT^*)^{\frac{1}{2}}. $$ An operator T is called a semi-hyponormal operator if $$ Q_T = $\mid$T$\mid$_r - $\mid$T$\mid$_l \geq 0. $$ In this paper, by using a technique introduced by Berberian [1], we show that the approximate point spectrum $\sigma_{ap}(T)$ of a semi-hyponomal operator T is empty.

• Journal of the Korean Mathematical Society
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• v.48 no.1
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• pp.117-132
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• 2011

By developing a linear algebra program involving many different structures associated to a three-graded H*-algebra, it is shown that if L is a Lie triple automorphism of an infinite-dimensional topologically simple associative H*-algebra A, then L is either an automorphism, an anti-automorphism, the negative of an automorphism or the negative of an anti-automorphism. If A is finite-dimensional, then there exists an automorphism, an anti-automorphism, the negative of an automorphism or the negative of an anti-automorphism F : A $\rightarrow$ A such that $\delta$:= F - L is a linear map from A onto its center sending commutators to zero. We also describe L in the case of having A zero annihilator.