• Microbiology and Biotechnology Letters
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• v.29 no.2
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• pp.110-114
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• 2001

Isolation of BacilLus sp. producing multi-enzyme and optimization of medium conditions for its production using feedstuffs for probiotics were carried out in this study. A bacterium isolated from natural resources, namely Bacillus subtilis 4-3, has multi-enzyme activity (phytase. cellulase, xylanasc, protease, and amylase. In the culture of B. subtilis 4-3 using soybean meal and rice bran. relatively low phytate degradation was noted using whereas high phytate degradability was observed with wheat bran (80.63%). The optimal composition of medium using feedstuffs was 1.0% (w/v) soybean meal and 2% (w/v) molasses to yield high cell growth.

• Journal of Plant Biotechnology
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• v.5 no.2
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• pp.107-113
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• 2003

The effect of sodium sulphate on shoot induction and multiple shoot formation from nodal explants of Vitex negundo L. was tested on Murashige and Skoog's (MS) medium fortified with different auxins, cytokinins and sucrose. Highest percentage $(97.78\%)$ of explants for shoot induction and multiple shoot (20.68/explant) production were observed in the combination treatment of $N^6-Benzyl$ adenine (BA) $(17.80\;{\mu}M/L)$, ${\alpha}-Naphthalene$ acetic acid (NAA) $(2.15\;{\mu}M/L)$ and $5\%$ sucrose supplemented with 100 mg/L sodium sulphate. In vitro raised shoots were rooted on the half-strength MS medium fortified with different concentrations of NAA, Indole-3-acetic acid (IAA), and Indole-3-butyric acid (IBA) alone and in combinations. Among the treatments, $4.90\;{\mu}M/L$ of IBA was found most effective $(95.56\%)$ in inducing roots. The rooted plantlets were shifted to glasshouse for acclimatization and later transferred to the field with cent percent survival. Furthermore, in vitro flowering was observed in the shoots cultured on MS medium supplemented with BA $(8.90\;{mu}M/L)$ and NAA $(1.61\;{\mu}M/L)$.

• Corrosion Science and Technology
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• v.21 no.3
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• pp.171-183
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• 2022

The performance and inhibitory action of the aqueous extract of Cyperus Conglomeratus's leaves against corrosion of XC70 steel in a 1M HCl acid medium are studied by the determination of the weight loss, the potentiodynamic polarization curves analysis, and electrochemical impedance measurements (electrochemical techniques). The corrosion inhibitory efficiency of XC70 steel increases with the increasing concentration of the green inhibitor, however, the corrosion rate of the steel decreases. Weight loss measurements show that the maximum percentage corrosion inhibition efficiency is approximately 61.86%, while the analysis of the mixed character polarization curves shows that the inhibitor could achieve an inhibition efficiency of 86.96%. The electrochemical impedance study confirmed that the value of the charge transfer resistance (R_ct) increases and the value of the double layer capacity (C_dl) decreases with increasing concentration of the aqueous extract of Cyperus Conglomeratus's leaves, thus increasing the inhibition efficiency. The study showed that this aqueous extract acts by adsorption on the metal surface; this adsorption follows the Langmuir isotherm. This research work showed that Cyperus Conglomeratus leaves extract acts as an effective and eco-friendly inhibitor on mild steel in an acid medium.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.53-56
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• 2000

Two-stage fed-batch culture was peformed to improve the volumetric productivity of erythritol. In the growth phase dissolved oxygen was maintained to 20% and the feed medium was automatically supplied to the fermenter by pH-stat mode. The cell yield was 0.76 g-cell/g-glucose. In two-stage fed-batch culture, 41% of total erythritol conversion yield with 187 g/L of erythritol concentration and 2.79 g/L-h of maximum erythritol Productivity were obtained when 400 g/L of glucose was directly added in the form of non-sterile powder at production phase. The erythritol productivity increased in parallel with cell mass. The metabolic shift in the biosynthetic pathway of erythritol was caused by dissolved oxygen concentration. The production of gluconic acid was observed when the dissolved oxygen in the medium was maintained over 40% during the production phase, whereas the dissolved oxygen concentration lower than 40% caused the production of citric acid. But the butyric acid was produced independently with dissolved oxygen concentration in the medium. The production of organic acids such as gluconic acid, citric acid, and butyric acid was decreased by addition of mineral salts.

• Applied Biological Chemistry
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• v.35 no.3
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• pp.210-217
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• 1992

A photosynthetic bacterium strain KUP-74 producing high amount of S-amino-levulinic acid(ALA) was isolated from soils, which was identified as Rhodocyclus gelatinosus. After 10 days cultivation under anaerobic-light condition at $30^{\circ}C$, 4 Klux and pH 6.8, 5 mg/l of ALA was formed extracellularly. ALA productions were increased up to 8 mg/l and 12 mg/l in cell cultivations either by the addition of 0.5% glycerol (v/v) or 10 mM of glycine and succinic acid, respectively, using Lascelles basal medium eliminated L-glutamic acid. By cultivation in the presence of 30 mM each D,L-glutamic acids and D,L-glutamines the yield of ALA showing a late induction phenomenon was reached the maximum value of 21 mg/l. Different culture times were needed to generate maximum ALA yields by the addition of initial precursors of $C_4$ and $C_5$ pathways in basal medium, as being 107 h and 262 h, respectively. 40 mg/l yield of ALA was observed by cell cultivation with the basal medium containing each 10 mM levulinic acid(LA) and glycine simultaneously.

• Korean Journal of Animal Reproduction
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• v.23 no.3
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• pp.263-270
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• 1999

This study was conducted to investigate effects of L-ascorbic acid and selenium on maturation, fertilization, and development ablity of porcine follicular oocytes in vitro. When the follicular oocytes were cultured in the media containing 0, 62.5, 100 and 300 $\mu$M of L-ascorbic acid for 40~44h, the percentages of germinal vesicle breakdown were 86.8, 92.9, 91.7 and 92.6% respectively, and the nuclear maturation rates (M II) were 44.7, 57.1, 52.8 and 53.7%. The nuclear maturation rates of treated groups were significantly higher than those of non-treated group (p＜0.05). When the follicular oocytes were cultured at 0, 0.4, 0.8, and $1.5\mu$M of selenium for 40~44h, the nuclear maturation rates of treated groups were significantly higher than those of non-treated group (p＜0.05). The addition of L-ascorbic acid or selenium to the maturation medium, the incidence of male pronuclear formation was significantly increased (p＜0.05) and polyspermy rate was significantly decreased (p＜0.05). The addition of L-ascorbic acid or selenium to the maturation medium increased the clevage rate, morula and blastocyst rate (p＜0.05). These results suggested that the addition of L-ascorbic acid and selenium to maturation medium increase the nuclear maturation rates, male pronuclear formation and normal embryonic development: in porcine oocytes matured and fertilized in vitro.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.97-102
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• 2017

Catechol type siderophore different from 2, 3-dihydroxybenzoic acid (DHB) was produced from Acinetobacter sp. B-W grown in medium containing L-glutamic acid as both carbon and nitrogen sole sources at $28^{\circ}C$. Optimal concentration of glutamic acid for siderophore production was 3% and production of siderophore was decreased above 3% glutamic acid. In previous report, siderophore, 2, 3-DHB was produced from strain B-W grown in medium containing glucose as carbon source and glutamic acid as nitrogen source. Rf value of siderophore produced from strain B-W grown in medium glutamic acid as both carbon and nitrogen sole sources at $28^{\circ}C$ was 0.32, while 2, 3-DHB was 0.84 in butanol-acetic acid-water (12:3:5) as developing solvent. Antioxidative activity of 2, 3-DHB was not detected in that siderophore produced from glutamic acid. Catechol nature of siderophore was detected by Arnow test. Although in iron-limited media optimal cell growth was identified at $36^{\circ}C$, significant quantities of siderophore were produced only at $28^{\circ}C$. Biosynthesis of siderophore was strongly inhibited by growth at $36^{\circ}C$. Production of siderophore was completely inhibited by $10{\mu}M\;FeCl_3$.

• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.343-348
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• 1989

Production of shikonin derivatives by Lithospermum erythrorhizon cells by using polyurethane foam was invesliigated. Shikonin derivatives were effectively adsorbed mostly by phase distribution to polyurethane matrices and their production increased significantly compared to the suspension culture. The enhanced production of shikonin was probably due to more facilitated cell to cell con-tact and lowered intracellular shikonin concentration, both of which are known to be favorable for plant secondary metabolite production. In order to improve the process productivity, tell culture was conducted under various culture conditions: Of them, Schenk and Hildebrandt medium containing indole-3-acetic acid (1.75mg/ι) and kinetin (0.1mg/ι) was considered most appropriate for shikonin production. Production of shikonin increased about 4.5 times in the Schenk and Hildebrandt medium containing indole-3-acetic acid (1.15mg/ι) and kinetin (0.1mg/ι) when compared to the same medium containing p-chlorophenoxyacetic acid (2.0mg/ι) and kinetin (0.1mg/ι). When poly-urethane was used as the support material, a single-stage system was more preferred to the conventional two-stage culture system in terms of shikonin productivity.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.998-1003
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• 2012

Pantoea agglomerans DSM3493 was isolated from green house soils collected from Chungchugnam-do province, Gongju-Gun area in South Korea and phosphate solubilization and organic acid production of the strain were assessed using three types of insoluble phosphate sources (Ca phosphate, Fe phosphate and Al phosphate) under three different pH conditions (7, 8 and 9). The highest Ca phosphate solubilization ($651{\mu}g\;mL^{-1}$) was recorded at pH 7 followed by pH 8 and 9 (428 and $424{\mu}g\;mL^{-1}$ respectively). The solubilization rate was found to be 80.4, 98.1 and $88.7{\mu}g\;mL^{-1}$ (for Fe phosphate containing medium) and 9.3, 12.1 and $29.8{\mu}g\;mL^{-1}$ (for the Al phosphate containing medium) respectively at pH 7, 8 and 9. Though increasing pH of the medium caused reduction in the rate of solubilization of Ca phosphate, solubilization of Fe and Al phosphates enhanced with increasing pH. By contrast, the highest amount of organic acid was produced with Ca phosphate while the lowest was recorded with the presence of Al phosphate. Among the organic acids, gluconic acid production was found to be the highest, followed by oxalic acid and citric acid regardless the source of phosphate. Results can thus be concluded that the production of organic acids appears to play a significant role in the inorganic phosphate solubilization.

• Mycobiology
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• v.43 no.1
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• pp.57-62
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• 2015

${\beta}$-Glucosidase, which hydrolyzes cellobiose into two glucoses, plays an important role in the process of saccharification of the lignocellulosic biomass. In this study, we optimized the activity of ${\beta}$-glucosidase of brown-rot fungus Fomitopsis pinicola KCTC 6208 using the response surface methodology (RSM) with various concentrations of glucose, yeast extract and ascorbic acid, which are the most significant nutrients for activity of ${\beta}$-glucosidase. The highest activity of ${\beta}$-glucosidase was achieved 3.02% of glucose, 4.35% of yeast extract, and 7.41% ascorbic acid where ascorbic acid was most effective. The maximum activity of ${\beta}$-glucosidase predicted by the RSM was 15.34 U/mg, which was similar to the experimental value 14.90 U/mg at the 16th day of incubation. This optimized activity of ${\beta}$-glucosidase was 23.6 times higher than the preliminary activity value, 0.63 U/mg, and was also much higher than previous values reported in other fungi strains. Therefore, a simplified medium supplemented with a cheap vitamin source, such as ascorbic acid, could be a cost effective mean of increasing ${\beta}$-glucosidase activity.