• Journal of Applied Biological Chemistry
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• v.48 no.1
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• pp.11-15
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• 2005

Salinity of soils in greenhouse has been increased by massive application of fertilizers. Nitrogen fertilizer was most popular, and thus nitrate became the majority of soil salinity. Accumulation of nitrate led to deleterious effects on the growth and development of crops and vegetables. Microbial strains able to utilize nitrate and thus remove excess nitrate from farm land soils were isolated from 15 different soils of greenhouses and plastic film houses. Four strains able to grow in medium containing 50 mM $KNO_3$ were isolated, among which only E0461 showed high capacity of nitrate uptake. Nitrate uptake by E0461 was dependent on culture medium and was increased by addition of tryptone and peptone. Although E0461 was able to grow without tryptone and peptone, growth was slow, and no nitrate uptake was observed. Nitrate appeared to facilitate E0461 growth in the presence of tryptone and peptone. Through kinetic analysis, nitrate uptake was measured at various concentrations of nitrate, and half-life was calculated. Nitrate concentration decreased with increasing incubation period, and plot between half-lives and initial concentrations of nitrate fitted to single exponential function. These results suggest one major factor plays an important role in microbial nitrate uptake.

• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.626-632
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• 2005

A new bacterium BL-2 excreting a novel cationic polyglucosamine biopolymer was isolated from the spoiled leaves of Chinese cabbage and identified as Enterobacter sp. BL-2. The isolated Enterobacter sp. BL-2 was cultivated in pH-stat fed-batch culture using acetic acid as the feeding stock at pH 8.0, resulting in 17.11 g/l of cells and 1.53 g/l of an extracellular biopolymer after 72 h. The excreted biopolymer was purified by a three-step procedure, involving ethanol precipitation and deproteinizations, to a nearly homogeneous state, and its molecular weight was found to be 106 kDa. It was composed of glucosamine, rhamnose, and galactose at a molar ratio of 86.4:1.6:1.0, respectively, indicating a rarely found novel high-glucosamine-containing biopolymer. The FT-IR and $^{13}C-NMR$ spectra of the novel cationic polyglucosamine biopolymer PGB-l revealed a close identity with chitosan from crab shell. It can effectively flocculate various suspended solids, including kaolin clay, $Ca(OH)_2,\;Al_{2}O_3$, active carbon, microbial cells, and acidic dyes.

• International Journal of Industrial Entomology and Biomaterials
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• v.33 no.1
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• pp.24-30
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• 2016

1-Deoxynojirimycin (DNJ) have been extensively investigated for their α-glucosidase inhibitor on postprandial hyperglycemia, and applied in nutraceuticals and medicine for preventing or delaying progression of type 2 diabetes. However, the amount of DNJ in mulberry leaves is low (about 0.1%), therefore, more effective extraction method is needed. This study was performed to develop microbial DNJ for biological methods of DNJ as an alternative to the chemical methods. In this study, we obtained evidence for Bacillus subtilis that produce DNJ in large quantities by high performance liquid chromatography. Inhibition of α-glucosidase activity was determined to DNJ production or non-production. Investigation of the effect of mulberry leaves powder concentration (1~5%), using the DNJ high-production bacteria, provided evidence for microbial mass production of DNJ. When the 4% mulberry leaf powder for 9 days was used, the α-glucosidase inhibitory activity was over the 85%. Also, the results presented in this study confirm DNJ yield's increasement in microbes using the various of nutrients and provide insight of ways to improve DNJ yields in microorganisms.

• 한국약용작물학회:학술대회논문집
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• 2006.11a
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• pp.127-130
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• 2006

Coenzyme Q10(CoQ10) is a biological quinine compound that is widely found in living organisms including yeast, plants, and animals. CoQ10 has two major physiological activities:(a)mitochondrial electron-transport activity and (b)antioxidant activity. Various clinical applications are also available : Parkinson's disease, Heart disease, diabetes. Because of its various application filed, the market size of CoQ 10 is continuously expanding all over the world. A Japanese company, Nisshin Pharma Inc. is the first industrial producer of CoQ10(1974). CoQ10 can be produced by fermentation and chemical synthesis. In several companies, these two methods are used for the production of CoQ10:chemical synthesis - Yungjin, Daewoong, Nishin Parma; fermentation - Kaneka, Kyowa, Yungjin, etc. Researchs in microbial production of CoQ10 have several steps: screening of producing microorganisms, strain development, fermentation process, purification process, scale-up process, plant production. Several strategies are available for the strain development : Random mutation and screening, directed metabolic engineering. For the optimization of fermentation process, various conditions (nutrient, aeration, temperature, culture type, etc.) are considered. Purification is one of the most important step because the quality of final products entirely depends on its purity. The production cost will be reduced and the quality of the CoQ10 will be impoved by continuous researches in strain development, fermentation process, purification process.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.71-77
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• 1998

The strain of Serratia marcescens QM B1466 produces selectively large amount of chitinolytic enzymes (about 1mg/L medium). Enzymatic hydrolysis of chitin to N-acetyl-${\beta}$-D-glucosamine (NAG) was performed with a system consisting of two hydrolases (chitinase and chitobiase) produced by optimization of a microbial host consuming chitin particles. For the development of Large-scale biological process for the production of NAG from chitinaceous waste, the selection and optimization of a microbial host, particle size of crab/shrimp chitin sources and initial induction time using chitin as a sole carbon source on chitinase/chitobiase production and NAG production were examined. Crab-shell chitin(1.5%) treated by dilute acid and , ball-milled with a normal diameter less than 250m gave the highest chitinase activity over a 7 days culture. Crude chitinase/ chitobiase solution obtained in a 10 L fed-batch fermentation showed a maximum activities of 23.6 U/mL and 5.1 U/mL, respectively with a feeding time of 3 hrs, near pH 8.5 at 30$^{\circ}C$.

• KSBB Journal
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• v.32 no.2
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• pp.160-167
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• 2017

Coating of individual cells with organic or inorganic materials has drawn a great deal of attention, because it provides the cells with physicochemical durability, which would contribute to the development of bioreactors, biosensor, and lab-on-a-chip, as well as to the fundamental studies in single cell-based biology. Although many strategies have been developed for coating of microbial cells, limited methods are available to coat mammalian cells because most mammalian cells do not have a robust membrane or exoskeleton. Instead, they are enclosed in a lipid bilayer, which is fluidic and vulnerable to changes in its environments. It is more difficult to treat mammalian cells in vitro than microbial cells because the surfaces of mammalian cells are not protected or reinforced by a tough coat. In this work, we report a cytocompatible and degradable nanocoat for mammalian cells. Three types of mammalian cells (HeLa cells, NIH 3T3 fibroblasts, and Jurkat T cells) were individually coated within metal-polyphenol. To maintain the viability of the mammalian cells, we performed the whole processes under strictly physiological culture conditions, and carefully selected nontoxic materials.

• The Plant Pathology Journal
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• v.21 no.3
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• pp.244-251
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• 2005

The induction of growth promotion on numerous crops by rhizobacteria is a well documented phenomenon. In case of tomato (Lycopersicon esculentum), fruit yield is higher in replant soil than that in fresh soil. To investigate what kind of rhizobacterium is involved, microbial community in rhizosphere and on rhizoplane of tomato plants from each soil was analyzed by dilution plating on selective media. Many Gram-negative bacteria and actinomycetes were isolated from tomato in replant soil. One Gram-negative rhizobacterium isolated was identified as Pseudomonas putida based on its biochemical characteristics, fatty acid methyl ester analysis and 16S rDNA sequence. This bacterium designated strain 17 inhibited the growth of Pseudomonas corrugata, and increased growth of tomato seedlings. In addition, its culture filtrate inhibited conidial germination of plant-pathogenic fungi such as Fusarium oxysporum f. sp. radicis-lycopersici, F. oxysporum f. sp. cucumerinum, and Nectria radicicola. Scanning electron microscopy revealed strain 17 colonized and persisted on the epidermal surfaces of tomato radicles and roots. These results suggest that P. putida strain 17 may serve as a biological control agent to suppress multiple soil-borne diseases for tomato plants. Increased microbial populations that suppress deleterious microorganisms including pathogens could be one of the major factors in increased tomato yield in replant soil.

• Journal of Ginseng Research
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• v.34 no.4
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• pp.321-326
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• 2010

Enzymatic treatment conditions for red ginseng residue (RGR) were investigated to apply RGR as a microbial medium. Polysaccharide hydrolyase and protease were screened to obtain high solid and carbohydrate yields, and a good degree of carbohydrate hydrolysis. The optimal dosage and reaction time for Viscozyme, the chosen polysaccharide hydrolyase, were found to be 1.0% (w/w) and 3 h, respectively. Of the tested proteases, Flavourzyme, whose optimal dosage was 0.5% (w/w), was selected. Co-treatment with the optimal dosages of Flavourzyme and Viscozyme increased solid yield, carbohydrate yield, and degree of carbohydrate hydrolysis by 76%, 65%, and 1,865%, respectively, over levels in non-treated RGR. The culture characteristics of Leuconostoc mesenteroides strain KACC 91459P grown in enzymatically hydrolyzed red ginseng residue (ERGR) and RGR suspensions were compared. After cultivation for 6 h, the viable cell counts of both cell suspensions rapidly increased to $1.3{\times}10^9$ colony-forming units (CFU)/g. Moreover, while the viable cell population drastically decreased to $2.4{\times}10^6\;CFU/g$ for cells grown in RGR medium, it was maintained in cells fermented in ERGR medium for 24 h.

• Korean Journal of Microbiology
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• v.11 no.3
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• pp.134-151
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• 1973

The physico-chemical and biological factors of coastal sea water were measured bimonthly from 1976 to 1979 for elucidating the relationship between microbial distribution and environmental factors at Masan and Jinhae bay. The experimental results are summarized as followings : 1) The polulation size of bactriz in sea water were increasing as the water temperature increased, and that was higher at station 2 and 3 than at station 1. The number of fungi showed the highest value on July on bottom. The population size of yeast showed no seasonal variation and also showed a relation with the geographic distance. 2) The correlationship between microbial distribution and environmental factors showed little coefficiency in surface water. And the other hand, at bottom water, between general bacteria and water temperature and dissolved oxygen, and between yeast and salinity, there were relatively high coefficiecy.

• Journal of Microbiology
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• v.43 no.5
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• pp.383-390
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• 2005

The diversity of the denitrifying bacterial populations in Daejeon Sewage Treatment Plant was examined using a culture-dependent approach. Of the three hundred and seventy six bacterial colonies selected randomly from agar plates, thirty-nine strains that showed denitrifying activity were selected and subjected to further analysis. According to the morphological and biochemical properties, the thirty nine isolates were divided into seven groups. This grouping was supported by an unweighted pair group method, using an arithmetic mean (UPGMA) analysis with fatty acid profiles. Restriction pattern analysis of 16S rDNA with four endonucleases (AluI, BstUI, MspI and RsaI) again revealed seven distinct groups, consistent with those defined from the morphological and biochemical properties and fatty acid profiles. Through the phylogenetic analysis using the 16S rDNA partial sequences, the main denitrifying microbial populations were found to be members of the phylum, Proteobacteria; in particular, classes Gammaproteobacteria (Aeromonas, Klebsiella and Enterobacter) and Betaproteobacteria (Acidovorax, Burkholderia and Comamonas), with Firmicutes, represented by Bacillus, also comprised a major group.