• Journal of Life Science
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• v.21 no.11
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• pp.1599-1606
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• 2011

To evaluate the effects of microorganism agents on oil biodegradation, treatability and microcosm studies were conducted. Petroleum oil degrading bacteria were isolated from enriched cultures of oil-contaminated sediment samples using a mineral salts medium (MSM) containing 0.5% Arabian heavy crude oil as the sole carbon source. After a 5 day-incubation period using MSM, mixed microorganisms of three species (strains BS1, BS2 and BS4) degraded 48.4% of aliphatic hydrocarbons and 30.5% of aromatic hydrocarbons. Treatability and microcosm tests were performed in the three different treatment conditions (AO: Arabian heavy crude oil, AO+IN: Arabian heavy crude oil+inorganic nutrient, AO+IN+MM: Arabian heavy crude oil+inorganic nutrient+mixed microorganism agents). Among these, significantly enhanced biodegradation of aliphatic hydrocarbons were observed in AO+IN and AO+IN+MM conditions, without showing any different biodegradation rates in either condition. However, the degradation rates of aromatic hydrocarbons in an AO+IN+MM condition were increased by 50% in the treatability test and by 13% in the microcosm test compared to those in an AO+IN condition. Taken together, it can be concluded that mixed microorganism agents enhance the biodegradation of aliphatic and aromatic hydrocarbons in laboratory, a treatability test, and a microcosm test. This agent could especially be a useful tool in the application of bioremediation for removal of aromatic hydrocarbons.

• KSBB Journal
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• v.17 no.4
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• pp.381-387
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• 2002

A filamentous fungus, strain FB01 showing high $\beta$-glucosidase activity was isolated from a compost. This fungus was cocultured with Trichoderma viride to enhance the productivity of $\beta$-glucosidase by changing inoculation time of the fungus. The microbial consortium showed higher cellulolytic enzyme production than T. viride alone. The maximal enzyme production was obtained when the microbial consortium was cultured at 30$\^{C}$ and pH 6.0 for 10 days with the activities of CMCase, $\beta$-glucosidase, and avicelase of 2.0, 0.8, and 0.2 U/mL, respectively. These enzyme activities were 2, 4, and 2 times as high as those of CMCase, p-glucosidase, avicelase from T. viride, respectively, indicating that a synergistic interaction appeared between T. viride and strain FBOI . The serial subcultures with pH control increased $\beta$-glucosidase production about 3.2 times. Enzyme production using ricestraw as a carbon source showed that the activities of CMCase, $\beta$-glucosidase, and avicelase were 3.69, 0.76, 0.17 U/mL, respectively, and $\beta$-glucosidase activity was 1.5 times higher than that of T viride.

• KSBB Journal
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• v.18 no.3
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• pp.174-179
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• 2003

The bacterium NFQ-1 capable of utilizing quinoline (2,3-benzopyridine) as the sole source of carbon, nitrogen and energy was enriched and isolated from soil samples of dead coal pit areas. Strain NFQ-1 was identified as Pseudomonas nitroreducens NFQ-1 by BIOLOG system, and assigned to Pseudomonas sp. NFO-1. Pseudomonas sp. NFQ-1 was used with the concentration range of 1 to 10 mM quinoline. Strain NFQ-1 could degrade 2.5 mM quinoline within 9 hours of incubation. Initial pH 8.0 in the culture was reduced to 6.8, and eventually 7.0 as the incubation was proceeding. 2-Hydroxyquinoline, the first intermediate of the degradative pathway, accumulated transiently in the growth medium. The highest concentration of quinoline (15 mM) in this work inhibited cell growth and quinoline degradation. Pseudomonas sp. NFQ-1 was able to utilize various quinoline derivatives and aromatic compounds including 2-hydroxyquinoline, p-comaric acid, benzoic acid, p-cresol, p-hydroxybenzoate, protocatechuic acid, and catechol. The specific activity of catechol oxygenases was determined to approximately 184.7 unit/㎎ for catechol 1.2-dioxygenase and 33.19 unit/㎎ for catechol 2,3-dioxygenase, respectively. As the result, it showed that strain NFQ-1 degraded quinoline via mainly orthp-cleavage pathway, and in partial meta-cleavage pathway.

• Journal of Ginseng Research
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• v.32 no.3
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• pp.270-274
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• 2008

A bacterium isolated from contaminated white ginseng was identified using API kit and electron microscope. This isolate was determined as rod shaped bacterium having about 1.0 ${\mu}m$ in diameter and 2.0 to 6.0 ${\mu}m$ in length. It had motility by peritrichous flagellum. The isolate had ${\beta}-galactosidase$, arginine dihydrolase and ornithin decarboxylase. It did not have ability not only to use citrate as sole carbon source and but also to produce $H_2S$. However, it could ferment glucose, manitol, sorbitol, rhamnose, arabinose and amygdalin. From these obserbations, the isolate was identified as Citrobacter sp. Ginseng saponin was added to culture of Citrobacter sp. in order to investigate saponin's influence on its growth. The strain was incubated at $38^{\circ}C$ for 3 days after addition of 0.05, 0.5, 2.0 and 4.0% (w/v) of saponin, respectively and the growth rates was investigated. The relative bacterial growth inhibition rates showed 28.6, 66.7, 92.4 and 97.7%, respectively, when compared with saponin non-treated group. These results suggest that the growth of Citrobacter sp. is inhibited by saponin in a concentration-dependent manner.

• Clean Technology
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• v.5 no.2
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• pp.79-86
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• 1999

Mutant strain EID was developed by treating Gordona sp. CYKS1 with ethylmethanesulfone, and the desulfurization characteristics of dibenzothiophene(DBT) by mutant EID was investigated. Strain EID desulfurized DBT to 2-hydroxybiphenyl (2-HBP) by 4S pathway. Desulfurization rate of the strain EID was $4.0{\mu}mol{\cdot}L^{-1}{\cdot}h^{-1}$, while that of the wild type CYKS1 was $2.6{\mu}mol{\cdot}L^{-1}{\cdot}h^{-1}$. The effect of glucose concentration supplied as the carbon source on the DBT desulfurization showed that DBT desulfurization rate was enhanced as the glucose concentration increased. Maximum DBT desulfurization rate was $11.1{\mu}mol{\cdot}L^{-1}{\cdot}h^{-1}$ at 2.0 mM DBT concentration. As end-products such as 2-HBP and sulfate concentrations increase, DBT desulfurization activity of the strain EID decreased. When 0.2 mM of 2-HBP was added in the medium, no growth and desulfurization activity was observed. When 0.5 g/L $Na_2SO_4$ was simultaneously supplied with DBT, DBT desulfurization rate was$1.4{\mu}mol{\cdot}L^{-1}{\cdot}h^{-1}$.

• Clean Technology
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• v.23 no.2
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• pp.121-132
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• 2017

The increase of greenhouse gases and the concern of global warming instigate the development and spread of renewable energy and hydrogen is considered one of the clean energy sources. Hydrogen is one of the most elements in the earth and exist in the form of fossil fuel, biomass and water. In order to use hydrogen for a clean energy source, the hydrogen production method should be eco-friendly and economic as well. There are two different hydrogen production methods: conventional thermal method using fossil fuel and renewable method using biomass and water. Steam reforming, autothermal reforming, partial oxidation, and gasification (using solid fuel) have been considered for hydrogen production from fossil fuel. When using fossil fuel, carbon dioxide should be separated from hydrogen and captured to be accepted as a clean energy. The amount of hydrogen from biomass is insignificant. In order to occupy noticeable portion in hydrogen industries, biomass conversion, especially, biological method should be sufficiently improved in a process efficiency and a microorganism cultivation. Electrolysis is a mature technology and hydrogen from water is considered the most eco-friendly method in terms of clean energy when the electric power is from renewable sources such as photovoltaic cell, solar heat, and wind power etc.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.248-254
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• 2010

To define the optimum conditions for the mass production of four antifungal Pseudomonas spp. isolated from soil, we have investigated culture conditions and effects of various nutrient sources on the bacterial growth and evaluated antagonistic activity against Rhizoctonia solani and Sclerotinia homoeocarpa, plant pathogens. The optimum temperature and pH for the growth of these isolates were determined as pH 7.0 and $20^{\circ}$ or $25^{\circ}C$, respectively. Sucrose, tryptone, and $K_2HPO_4$ generally were more adequate for better growth as carbon, nitrogen and mineral source, respectively. The nutrient sources were also found to be very effective for high antifungal activities against R. solani and S. homoeocarpa. It was elucidated that YUD-F group (P. mandelii and P. fluorescens), which inhabit regions at relatively low temperature, had more broad spectrum and higher antifungal activity than YUD-O group (P. trivialis and P. jessenii) generally against R. solani and S. homoeocarpa. It is thought that the differences of the average temperature in the various habitats of Pseudomonas spp. influence the optimal growth temperature and antifungal activity. Especially, Pseudomonas spp. of YUD-O group showed the better antifungal activity against dollar spot caused by S. homoeocarpa, but showed relatively weaker antifungal activity against brown patch caused by R. solani.

• The Korean Journal of Mycology
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• v.27 no.4 s.91
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• pp.304-311
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• 1999

Batch kinetics during the exo-polysaccharide (EPS) fermentation of Ganoderma lucidum was investigated as a function of different substrates (glucose and starch), substrate concentration $(1{\sim}7%,\;w/v)$ and subculture (3 times). Logistic model for mycelial growth fitted the experimental data better than Monod and two thirds power model. The Luedeking-Pirt equation was adequate to fit the kinetic data of product formation and substrate consumption. The EPS production was strongly non-growth associated, although it was mixed type. The product formation and sustrate consumption by growth associated mechanism decreased as the concentration of glucose increased, while those of the non-growth associated mechanism increased. However, starch medium increased the growth associated and non-growth associated substrate consumption indicating higher availability of substrate. Also, batch culture in starch medium showed the higher specific growth rate and stability during subculture than those in glucose medium. In conclusion, the enhanced EPS production and stability in the subculture was found to be remarkably improved by use of starch as sole carbon source in medium. The maximum mycelium dry weight and EPS production of 9.463 and 10.410 g/l, respectively, were obtained after shake culture of 7 days at $30^{\circ}C$ from the media containing 7% starch.

• Journal of Life Science
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• v.18 no.1
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• pp.103-108
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• 2008

An agar-degrading marine bacterium, strain AS-1 was isolated from the seawater. The strain AS-1 was identified as Sphingomonas paucimobilis (90% probability) by VITEK. The optimum medium for agarase activity of the isolated strain was determined to be marine medium, marine broth 2216 containing 0.1% agar as carbon source. An extracellular agarase was purified 104-fold from the culture supernatant by ammonium sulfate precipitation, ion exchange chromatography and gel filtration methods. The molecular weight of the purified enzyme was estimated to be 80 kDa by SDS-PAGE. The optimum pH and temperature for activity were 7.0 and $40^{\circ}C$, respectively. Antioxidative activity of the strain AS- was 72% in the supernatant cultured for 12 h. The culture supernatant of the strain AS-1 showed antibacterial activity against bacteria causing putrefaction and food poisoning such as Escherichia coli, Staphylococcus aureus and Proteus vulgaris. However, the cell growth of the lactic aicd forming strain, Lactobacillus plantarium was promoted by the treatment of 10% culture supernatant of an agar-degrading strain.

• Journal of Life Science
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• v.18 no.1
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• pp.84-90
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• 2008

Bacterial colonies which were able to oxidize the manganese were isolated from six soil samples in Byungchon area. Among them, one bacterial strain was selected for this study based on its high manganese oxidation activity. This selected bacterial strain was identified as Pseudomonas sp. MN5 through physiological-biochemical test and analysis of its 16s rRNA sequence. This selected bacterial strain was able to utilize fructose and maltose, but they doesn't utilizing various carbohydrates as a sole carbon source. Pseudomonas sp. MN5 showed a very sensitive to antibiotics such as kanamycin, chloramphenicol, streptomycin and tetracycline, but a high resistance up to mg/ml unit to heavy metals such as lithium, manganese and barium. Optimal manganese oxidation condition of Pseudomonas sp. MN5 was pH 7.5 and manganese oxidation activity was inhibited by proteinase K and boiling treatment. The manganese oxidizing protein produced by Pseudomonas sp. MN5 was purified by ammonium sulfate precipitation, HiTrap Q FF anion exchange chromatography and G3000sw $_{XL}$ gel filtration chromatography. By sodium dodecyl sulfate polyacrylamide gel electrophoresis, three manganese oxidizing protein with estimated molecular weights of 15 kDa, 46.7 kDa and 63.5 kDa were detected. Also, it was estimated that manganese oxidizing protein produced by Pseudomonas sp. MN5 were a kind of porin proteins through internal sequence and N-terminal sequence analysis.