• Korean Journal of Microbiology
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• v.34 no.4
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• pp.212-218
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• 1998

An obligately methylotrophic bacterium which produces extracellular polysaccharide (EPS) was isolated through methanol-enrichment culture technique. The isolate was aerobic, nonmotile, and gram negative rod and exibited catalase, but no oxidase, activity. Plasmid, carotenoid, and poly-${\beta}$-hydroxybutyric acid were not found. The guanine plus cytosine content of DNA was 52-56%. The isolate was found to grow only on methanol and monomethylamine. Growth was optimal ($t_d=2.4h$) at $35^{\circ}C$ and pH 6.5 in a mineral medium containing 0.5% (v/v) methanol, 25 mM phosphate, and 0.212% ammonium sulfate. Methanol was assimilated through the ribulose monophosphate pathway. Maximun amount of EPS was produced in cells growing at the mid-stationary growth phase at $30^{\circ}C$ in a mineral medium (PH 6.5) containing 1.0% (v/v) methanol in the CIN ratio of 54.7. Thin-layer chromatographic and high performance liquid chromatographic analysis revealed that the EPS was composed of glucose and galactose. EPS which was not treated with ethanol (Pbe) exhibited stable viscosity under various concentrations of salts and temperatures hut showed high viscosity at low pH. EPS precipitated with ethanol (Pae) was found to be more stable in viscosity than the Pbe at various salt concentrations, temperatures, and pH. The Pae also exhibited higher viscosity than the Pbe and xanthan gum. Scanning electron microscopy revealed that the lyophilized Pbe and Pae have a multi-layered structure and a structure of thick fibers, respectively.

• Korean Journal of Environmental Agriculture
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• v.36 no.3
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• pp.201-210
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• 2017

BACKGROUND: The current study was to monitor of 9 veterinary antibiotics (ceftiofur, clopidol, florfenicol, sulfamethazine, sulfamethoxazole, sulfathiazole, tetracycline, tiamulin, and tylosin) in manure using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive and negative electrospray ionization mode. METHODS AND RESULTS: Sample preparation was carried out using Mcllvaine buffer and citrate salts to adjust the pH of the sample followed by purification with dispersive solid phase extraction (d-SPE). Separation of analytes during LC-MS/MS analysis was conducted using an Eclipse Plus $C_{18}$ column and the mobile phase was in gradient mode with, 0.1% formic acid and 5 mM ammonium formate in methanol (A) and 0.1% formic acid and 5 mM ammonium formate in distilled water (B). The linearity of the matrix-matched calibrations of all tested antibiotics was good, with $R^2$ determination coefficients ${\geq}0.9920$. The limit of detection (LOD) and quantifications (LOQ) were $0.1-67.0{\mu}g/kg$ and $0.4-200.0{\mu}g/kg$, respectively. Analysis of 13 solid and liquid manure samples taken from the Republic of Korea revealed concentrations less than $0.7{\mu}g/kg$ for tiamulin, $1497.6{\mu}g/kg$ for sulfamethazine. CONCLUSION: To monitor 9 veterinary antibiotics from manure samples in 13 provincial areas throughout the Republic of Korea, an analytical method was developed. The developed method was fully validated and successfully applied for monitoring various veterinary antibiotics in manure samples.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.7
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• pp.1125-1132
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• 2013

In the kimchi manufacturing process, the starter is cultured on a large-scale and needs to be supplied at a low price to kimchi factories. However, current high costs associated with the culture of lactic acid bacteria for the starter, have led to rising kimchi prices. To solve this problem, the development of a new medium for culturing lactic acid bacteria was studied. The base materials of a this novel medium consisted of Chinese cabbage extract, a carbon source, a nitrogen source, and inorganic salts. The optimal composition of this medium was determined to be 30% Chinese cabbage extract, 2% maltose, 0.25% yeast extract, and $2{\times}$ salt stock (2% sodium acetate trihydrate, 0.8% disodium hydrogen phosphate, 0.8% sodium citrate, 0.8% ammonium sulfate, 0.04% magnesium sulfate, 0.02% manganese sulfate). The newly developed medium was named MFL (medium for lactic acid bacteria). After culture for 24 hr at $30^{\circ}C$, the CFU/mL of Leuconostoc (Leuc.) citreum GR1 in MRS and MFL was $3.41{\times}10^9$ and $7.49{\times}10^9$, respectively. The number of cells in the MFL medium was 2.2 times higher than their number in the MRS media. In a scale-up process using this optimized medium, the fermentation conditions for Leuc. citreum GR1 were tested in a 2 L working volume using a 5 L jar fermentor at $30^{\circ}C$. At an impeller speed of 50 rpm (without pH control), the viable cell count was $8.60{\times}10^9$ CFU/mL. From studies on pH-stat control fermentation, the optimal pH and regulating agent was determined to be 6.8 and NaOH, respectively. At an impeller speed of 50 rpm with pH control, the viable cell count was $11.42{\times}10^9(1.14{\times}10^{10})$ CFU/mL after cultivation for 20 hr - a value was 3.34 times higher than that obtained using the MRS media in biomass production. This MFL media is expected to have economic advantages for the cultivation of Leuc. citreum GR1 as a starter for kimchi production.

• Korean Journal of Agricultural Science
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• v.3 no.1
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• pp.105-119
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• 1976

Sucrose, glucose, starches hydrolyzates and raw starchy materials hydrolyzates were caramelized using various catalysis and the caramel products were analysed, in order to carry out the basic research for the replacement of caramel coloring. The results obtained were summarized as follows. 1. The caramel which was manufactured by sucrose syrup being pH 3.5 adjusted by sulfuric acid showed strong color intensity and hue as well as good stability in the solutions of table salt, tannin and alcohol. 2. The product caramelized from sucrose syrup being pH 9.5 adjusted by sodium carbonate showed very strong color intensity and black color component, and was quite stable in alcohol solution but not in table salt and tannin solutions. 3. The caramel products made from sucrose syrup using ammonium salts of strong acid like $NH_4Cl$ and $(NH_4)_2SO_4$ as catalyst showed strong color intensity and black color component but hazy apparence in solution of table salt, tannin and alcohol. 4. The product caramelized from glucose syrup being pH 9.5 adjusted by sodium carbonate indicated strong color intensity but weak red color component and was transparent in solution of table salt and alcohol but hazy in tannin solution. 5. In glucose caramel using $NH_4Cl$, $(NH_4)_2SO_4$, $(NH_4)_2CO_3$ and $(NH_4)_2SO_3$ as catalyst, $NH_4Cl$ plot was very weak in color intensity and insufficient in red color component but stable in solution of table salt, tannin and alcohol. In the case of $(NH_4)_2CO_3$, $(NH_4)_2SO_4$ and $(NH_4)_2SO_3$ plots, all products were strong in color intensity but little insufficient in red color component. On the stability in solutions, $(NH_4)_2SO_3$ plot was stable in two solutions expect tannin solution, $(NH_4)_2CO_3$ plot was only stable in alcohol solution and $(NH_4)_2SO_3$ plot was only stable in table salt solution. 6. When the acid hydrolyzed starch syrups without neutralization were caramelized using $(NH_4)_2SO_4$ as catalyst, the potato starch hydrolyzate caramel showed higher in color intensity being similar to its of glucose caramel than sweet potato starch hydrolyzate caramel and corn starch hydrolyzate caramel. 7. Dried sweet potato powder, dried acorns powders, the acorns (from Q. serrata THUNB and Q. acutissima CARR.) powders extracted with water for 7 days and with 50% alcohol solution for 24 hrs were hydrolyzed by sulfuric acid in autoclave at $3.5kg/cm^2$ as pressure for 60 mins, and were caramelized using $(NH_4)_2SO_4$ as catalyst. It was supposed that all of those products were poor quality on color and stability in solutions at the viewpoint of food coloring matter.

• Korean Journal of Agricultural Science
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• v.16 no.2
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• pp.225-238
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• 1989

These studies were conducted to investigate the extraction, purification and characterization of oriental pear (Niitaka. Pyrus pyrifolia Nak.) protease, and the results obtained were as follows: 1. Oriental pear protease was effectively extracted by the method of homogenizing pear pulp with 0.7 volume of 0.1M-sodium phosphate buffer, pH 6.5 containing 5mM-cysteine, 40mM-2-mercaptoethanol and 2mM-EDTA at 10,000 rpm for 5 min. 2. The protease was purified by ammonium sulfate fractionation, Sephadex G-100 filtration and DEAE-Sephadex A-50 column chromatography, and the purified enzyme gave a single protein band on polyacrylamide gel electrophoresis. 3. The specific activity of purified enzyme was 29.65 unit/mg protein and the yield was 7.22%. 4. The moecular weight of the protease was estimated to be about 51,000 by SDS-polyacrylamide gel electrophoresis, and the enzyme had Km value of 54.5 mg/ml for casein. 5. The purified enzyme had a maximum activity at pH 6.0 and $50^{\circ}C$, and was stable from pH 5.5-6.5 and at temperatures below $50^{\circ}C$ 6. Casein was a better substrate for this protease compared to hemoglobin. 7. The enzyme activity was markedly inhibited by p-chloromercuribenzoic acid and heavy metal salts such as $HgCl_2$ and $MnSO_4$ also considerably inhibited the enzyme activity.

• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.461-466
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• 2010

In this study the feasibility of simultaneous electricity generation and treatment of swine farm wastewater using microbial fuel cells (MFCs) was examined. Two single-chamber MFCs containing an anode filled with different ratio of graphite felt and stainless-steel cross strip was used in all tests. The proportion of stainless-steel cross strip to graphite felt in the anode of control microbial fuel cell (CMFC) was higher than that of swine microbial fuel cell (SMFC) to reduce construction costs. SMFCs produced a stable current of 18 mA by swine wastewater with chemical oxygen demand (COD) of $3.167{\pm}80\;mg/L$ after enriched. The maximum power density and current density of SMFCs were $680\;mW/m^3$ and $3,770\;mA/m^3$, respectively. In the CMFC, power density and current density was lower than that of SMFC. CODs decreased by the SMFC and CMFC from $3.167{\pm}80$ to $865{\pm}21$ and $930{\pm}14\;mg/L$, achieving 72.7% and 70.6% COD removal, respectively. The suspended solid (SS) of both fuel cells was also reduced over 99% ($4,533{\pm}67$ to $24.0{\pm}6.0\;mg/L$). The concentration of nutritive salts, ${NH_4}^+$, ${NO_3}^-$, and ${PO_4}^{3-}$, dropped by 65.4%, 57.5%, and 73.7% by the SMFC, respectively. These results were similar with those of CMFC. These results show that the microbial fuel cells using electrode with mix stainless-steel cross strip and graphite felt can treat the swine wastewater simultaneously with an electricity generation from swine wastewater.

• Applied Biological Chemistry
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• v.22 no.2
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• pp.123-134
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• 1979

For the purpose of developing a microbial insecticide utilizing Bacillus thuringiensis Berliner, research was done and the following results were obtained. 1) As the freeze-dried matter of the cocoon-cooked water discarded from the filature contains much crude protein(51.825%) and a lot of inorganic salts, it can make a good nutrition source for the culture cf B. thuringiensis Berliner. 2) Based on the suspensibility, formula F-5 turned out to be the most suitable for insecticidal use. Its composition includes 0.2 g of the cell-spore-crystal mixture, 25 g of 200-mesh kaolin, 2.5 g of New Kalgen-NX-150, and 2.5 g of glycerine admixed with 8 ml of distilled water and granulated in 80-mesh size. 3) All the components of F-5, F-6 and F-7 are identical except that the amounts of cell-spore-crystal mixture of F-5, F-6, and F-7 are 0.2 g, 0.4 g, and 0.6 g, respectively. Accordingly, their physical properties are almost all the same. 4) Formulas F-5, F-6, and F-7 exhibited an excellent toxicity to Anomis mesogona Walker, Dendrolimus spectabilis Butler, and Margaronia perspectalis Walker at the concentration of 5%. 5) Formulas F-8 and F-9 which contain $NaHCO_3$ as one of their components showed a remarkably reduced toxicity to Anomis mesogona Walker and Dendrolimus spectabilis Butler than F-6 which does not contain $NaHCO_3$. 6) A maximum of $2.97{\times}10^9$ spores per ml was obtained by incubating B. thuringiensis in M-3 which has a pH of 7.05 and comprises 0.2% of ammonium sulphate and 0.8% of glucose dissolved in the cocoon-cooked water, with aeration for 96 hours. 7) Formula F-6 exhibited a somewhat reduced toxicity to Anomis mesogona Walker and Dendrolimus spectabilis Butler, when stored at room temperature for 70 days after formulation and it is desirable to keep it in a dark and cold place. 8) In held applications, formula F-6 showed a good activity in controlling Monema flavescens Walker. Margaronia perspectalis Walker, and Macrosiphum ibarae Matsumura.