• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.319-324
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• 1991

Three strains able to efficiently produce ethanol from cellulosic hydrolysates were isolated from soil samples by enrichment culture in liquid saccharified wheat bran medium. The profiles of physiological and biochemical properties of two yeasts KM-09 and KM-402 and a bacterium Hg-225 were almost identical from those of Candida sp. and Klebsiella sp., respectively. Strains KM-09 and HG-225 used xylose and cellobiose as fermentable sugars, and HG-225 had a wide range of sugar utilization for ethanol fermentation. The optimal pH and temperature for growth of KM-09, KM-402 and HG-225 were 5.8, 5.6 and 6.8 and 32t, $30^{\circ}C$~ and $38^{\circ}C$, respectively. During the ethanol fermentation in saccharified wheat bran by the isolated strains, optimal temperature for ethanol production was more or less higher than those for growth, and addition of 0.2% (w/v) $MgSO_4$, into the medium enhanced ethanol productivity. Of the three strains ethanol content of KM-09 was the highest with about 2.3% (v/v), and ethanol production rate of HG-225 was faster than the others and maximum productivity was after 4 days. KM-09 (1.42% v/v) and HG-225 (1.05%, vlv) produced ethanol from 4% (wIv) xylose but growth rate was slower than on glucose. Otherwise KM-402 showed the highest ethanol productivity on glucose, but no ethanol was detected on xylose and cellobiose.

• Applied Biological Chemistry
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• v.44 no.4
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• pp.246-250
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• 2001

In order to produce alkaline protease, psychrotrophic Bacterium which have high enzyme activity, was isolated by using enrichment culture from soil samples and identified as genus Bacillus sp. The optimal pH and temperature for the enzyme activity were pH 6 and $40^{\circ}C$. The temperature range of high enzyme activity was $20{\sim}40^{\circ}C$. The optimal initial pH of culture condition for enzyme was pH 6. The most favorable carbon and nitrogen sources for the production of protease by Bacillus sp. WRD-2 were 3% maltose and 4% yeast extract, respectively.

• Journal of Ginseng Research
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• v.45 no.1
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• pp.86-97
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• 2021

Background: Panax ginseng Meyer has been used as a nourishing edible herb in East Asia for thousands of years. 25-OH-PPT was first discovered as a natural rare triterpenoid saponin in ginseng stems and leaves by our group. Research found that it showed strong inhibitory effects on α-glucosidase and protein tyrosine phosphatase 1B, and protected cardiocytes (H9c2) through PI3K/Akt pathway. Methods: In the research, in order to optimize the 25-OH-PPT enrichment process, optimal macroporous resins and optimal purification conditions were studied. Meanwhile, the hypoglycemic effect and mechanism of 25-OH-PPT were evaluated by using STZ to establish insulin-dependent diabetic mice and the spontaneous type 2 diabetes DB/DB mice. Results and Conclusion: Research found that 25-OH-PPT can reduce blood glucose and enhance glucose tolerance in STZ model mice. It increases insulin sensitivity by upregulating GLUT4 and AMPK in skeletal muscle, and activating insulin signaling pathways. In DB/DB mice, 25-OH-PPT achieves hypoglycemic effects mainly by activating the insulin signaling pathway. Meanwhile, through the influence of liver inflammatory factors and lipids in serum, it can be seen that 25-OH-PPT has obvious anti-inflammatory and lipid-lowering effects. These results provide new insights into the study of ginseng as a functional food.

• Journal of Microbiology and Biotechnology
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• v.6 no.3
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• pp.167-172
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• 1996

The bacterial strain P2 degrading polychlorinated biphenyls (PCBs) was isolated from the soil around the Shinchun stream in Taegu after enrichment culture in a media containing biphenyl as the sole carbon source. The isolate was identified as a strain of Pseudomonas sp. based on its morphological and physiological characteristics. The optimal conditions of initial pH of media and temperature for growth were 7.0 and $30^{\circ}C$, respectively. Degradation of biphenyl and PCBs was confirmed by GC during the culture of Pseudomonas sp. P2 in a media containing them at a concentration of 500 mg/I. It was observed that Pseudomonas sp. P2 could degrade 97.0$%$ of biphenyl and 60.0$%$ of PCBs after 160 h culture.

• Journal of Microbiology
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• v.45 no.6
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• pp.521-527
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• 2007

Several yeast strains degrading malic acid as a sole carbon and energy source were isolated from Korean wine pomace after enrichment culture in the presence of malic acid. Among them, the strain designated as KMBL 5774 showed the highest malic acid degrading ability. It was identified as Issatchenkia orientalis based on its morphological and physiological characteristics as well as the nucleotide sequences of the internal transcribed spacer (ITS) 1-5.8S rDNA-ITS II region. Phylogenetic analysis of the ITS I-5.8S rDNA-ITS II sequences showed that the KMBL 5774 is the closest to I. orientalis zhuan 192. Identity of the sequences of the KMBL 5774 was 99.5% with those of I. orientalis zhuan 192. The optimal pH of the media for the growth and malic acid degradation by the yeast was between 2.0 and 3.0, suggesting that the strain is an acidophile. Under the optimized conditions, the yeast could degrade 95.5% of the malic acid after 24 h of incubation at $30^{\circ}C$ in YNB media containing 2% malic acid as a sole carbon and energy source.

• Progress in Superconductivity and Cryogenics
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• v.19 no.1
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• pp.17-21
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• 2017

Vanadium slags is a kind of vanadiferous solid waste from steelmaking process. It not only occupies land, pollutes environment, but also leads to waste of resources. Based on the difference of magnetic susceptibility of different particles caused by their chemical and physical properties from vanadium slag, a new technology, superconducting high gradient magnetic separation was investigated for separation and extraction of valuable substances from vanadium slag. The magnetic concentrate was obtained under optimal parameters, i.e., a particle size -200 mesh, a magnetic flux density of 0.8 T, a slurry concentration of 5 g/L, an amount of steel wools of 25 g and a slurry flow velocity of 2 L/min. The content of $Fe_2O_3$ in concentrate could be increased from 39.6% to 55.0% and $V_2O_5$ from 2.5% to 4.0%, respectively. The recovery rate is up to 42.9%, and the vanadium slag has been effectively reused.

• Journal of Microbiology and Biotechnology
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• v.4 no.2
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• pp.126-133
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• 1994

A Pseudomonas putida strain able to accumulate high amount of polyesters of medium-chain-length 3-hydroxyalkanoic acids ($PHA_{MCL)$) was isolated from soil in a landfill site using an enrichment technique. Culture condition of the isolated strain for polyester production in a one-step culture was optimized in a mineral-salts medium against pH and concentrations of ammonium sulfate, carbon source(e.g., octanoate), and phosphate. The optimal values for maximal cell growth and PHA accumulation were: pH; 7$\sim$8, $(NH_4)_2SO_4$; 8 mM, octanoate; 40 mM. The optimum temperature was in the range of $20\sim30^{\circ}C$, which was rather broader than in other bacteria. Cell growth was strongly inhibited by the phosphate limitation to less than 1 mM. An increase of phosphate concentration above 1 mM showed little effect on cell growth and polyester accumulation. When the strain was grown on octanoate under this optimized condition it produced 3.4 g dry biomass per liter and yielded 1.7 g PHA per liter amounting to 53 wt% of dry cells. The monomer units composing the polyester synthesized from octanoate were 3-hydroxyoctanoate (3HO), 3-hydroxycaproate (3HC), and 3-hydroxybutyrate (3HB) (85:13:2, mole ratio). Other low linear $C_3\simC_{10}$ monocarboxylic acids were also tested for polyester production.

• Journal of Microbiology and Biotechnology
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• v.5 no.2
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• pp.80-86
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• 1995

The bacterial strain WC-17 able to produce chitinase was isolated from soil using an enrichment technique. The isolated strain was identified as Acinetobacter sp. judging by their morphological and physiological characterisitics. The optimal culture conditions for the production of chitinase of Acinetobacter sp. WC -17 are 1.5% colloidal chitin and 1 % tryptone at $30^{\circ}C$ with pH 6.5. Since the enzyme was rapidly produced in a culture supplied with chitin, glucose, or N-acetylglucosamine but not with other polymers and monosaccharide, the enzyme was considered to be an inducible enzyme. Notably N- acetylglucosamine and glucose were found to be effective inducers at low concentrations but repressors at excessive concentrations. The cultural supernatant of Acinetobacter sp. WC-17 inhibited the growth of phytopathogenic fungi such as P.oryzae, R.solani, and F.solani. Among the phytopathogenic fungi tested, P.oryzae was the most sensitive. The conventional agar plate (PDA containing 1 % colloidal chitin) method also produced the same result.

• Smart Structures and Systems
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• v.21 no.1
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• pp.123-137
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• 2018

Structural monitoring is the most important part of the construction and operation of the embankment dams. Appropriate instruments selection for dams is vital, as inappropriate selection causes irreparable loss in critical condition. Due to the lack of a systematic approach to determine adequate instruments, a framework based on three comparable Multi-Attribute Decision Making (MADM) methods, which are VIKOR, technique of order preference by similarity to ideal solution (TOPSIS) and Preference ranking organization method for enrichment evaluation (PROMETHEE), has been developed. MADM techniques have been widely used for optimizing priorities and determination of the most suitable alternatives. However, the results of the different methods of MADM have indicated inconsistency in ranking alternatives due to closeness of judgements from decision makers. In this study, 9 criteria and 42 geotechnical instruments have been applied. A new method has been developed to determine the decision makers' importance weights and an aggregation method has been introduced to optimally select the most suitable instruments. Consequently, the outcomes of the aggregation ranking correlate about 94% with TOPSIS and VIKOR, and 83% with PROMETHEE methods' results providing remarkably appropriate prioritisation of instruments for embankment dams.

• Microbiology and Biotechnology Letters
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• v.25 no.5
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• pp.520-526
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• 1997

Bacterial strains which degrade Arabian Light crude oil were isolated by enrichment culture from oil-spilled soil. The strain A54 was finally selected after testing emulsifying activity and oil conversion rate. Strain A54 was identified as a Acinetobacter sp. based on the morphological, biochemical and physiological characteristics. It appears to be highly specialized for growth on Arabian Light crude oil in minimal salts medium since it showed preference for oil or degradation products as substrates for growth. It was found that it could grow on at least fifteen different hydrocarbons. The optimum cultural and environmental conditions were as follows; 25$\circ$C for temperature, 7,5 for pH, 2.0% for NaCl concentration and 2.0% for crude oil concentration. Additionally, the optimal concentration of NH$_{4}$NO$_{3}$, and K$_{2}$HPO$_{4}$, were 12.5 mM and 0.057 mM, respectively. Cell growth and emulsifying activity as a function of time were also determined. Crude oil degradation and the reduction of product peaks were identified by the analysis of remnant oil by gas chromatography. Approximately 63% of crude oil were converted into a form no longer extractable by mixed organic solvents.