• KSBB Journal
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• v.16 no.5
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• pp.523-525
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• 2001

Curdlan is one biopolymer composed of ${\beta}$1,3-glucan and dissolved in a alkali solution but formed salt under neutral or acid condition. It was produced by Agrobactrium species and the separation process is necessary to make pure curdlan from the culture broth. The pH swing separation method was as feasible separation process using solubility changes with the pH difference. however, this method requires a lot of acid and alkali solution also produces a lot of waste. Therefore, an efficient process which could save energy and minimize toxic waste was developed. A density gradient separation process was developed in this research. High density sucrose solution was used as a separation agent. Curdlan was separated from the culture broth when the density of the sucrose solution was 1.15 g/L. Since the curdlan was produced on the surface of cell wall. the pre-treatment of culture broth was necessary. Curdlan recovery yield was increased up to 83% with the homogenization of the culture broth and further increased up to 87% with the treatment of alkai-acid solution.

• Microbiology and Biotechnology Letters
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• v.26 no.3
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• pp.257-263
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• 1998

Alcaligenes eutrophus was successfully recovered from high cell density broth by pre-treatment with Fe-based coagulants. An inorganic coagulant, Fe$_2$(SO$_4$)$_3$, and a polymerized coagulant, Ferix-3, were used. Good coagulation was observed in broad pH range of 3 to 13, the floe size was increased with increasing pH of culture broth. The optimum pH of fermentation broth for cell recovery was 10 to 13. The optimum coagulant dosages to recover cells with 95% cell recovery were increased with increasing cell concentration. Optimal coagulant dosage was lower when the polymerized coagulant was used rather than the inorganic coagulant. The coexistence of NH$_4$$\^$+/ was increased coagulant requirement, and the coagulant requirement was 0.066g Fe$_3$$\^$+//g NH$_4$$\^$+/.

• Korean journal of applied entomology
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• v.49 no.3
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• pp.241-249
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• 2010

Two groups of entomopathogenic bacteria, Xenorhabdus and Photorhabdus, are known to suppress insect immune responses by inhibiting eicosanoid biosynthesis. This study used these bacterial culture broths to develop novel biochemical insecticides against the diamondback moth, Plutella xylostella. Though the bacterial culture broths alone showed little insecticidal activity, they significantly enhanced pathogenicity of Bacillus thuringiensis against the fourth instar larvae of P. xylostella. Sterilization of the bacterial culture broth by autoclaving or $0.2\;{\mu}m$ membrane filtering did not influence the synergistic effect on the pathogenicity of B. thuringiensis. Three metablites identified in the culture broth of X. nematophila also showed similar synergistic effects. In field test, both entomopathogenic bacterial culture broth also enhanced the control efficacy of B. thuringiensis against P. xylostella.

• Microbiology and Biotechnology Letters
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• v.29 no.3
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• pp.162-168
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• 2001

For lactic acid fermentation of chestnut broth,10 strains of bacteria were isolated from human feces and commercial yogurt,6 of which were identified to be Bifidobacterium and the rest isolated from Acidities of the chestnut broths fermented by these strains were lower than yogurt, but more than two times higher than yogurts made from seeds or vegetables including soy milk. To stimulate acidity of the fermented broths, addition of yeast extract and tryptone peptone were the most effective at the concentration of 0.2 and 0.4%, respectively, while glucose addition above 0.5% up to 8% did not increased the acid production except a few strains of Lactoba- Cillus. Among the tested fruits and vegetables, carrot juice supplementation was the most effective in acid produc- tion by most of the tested strains. Saccharification of chestnut broth by hydrolyzing process greatly increased the acid production at 25% of cooked chestnut. However, compared to the results from the 8% of unhydrolyzed chest- nut, the net increase in acid production by hydrolysis was not much stimulative.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.695-702
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• 2015

Liquid-liquid extraction (LLE) using various solvents was studied for recovery of acetic acid from a synthetic ethanol fermentation broth. The microbial fermentation of sugars presented in hydrolyzate gives rise to acetic acid as a byproduct. In order to obtain pure ethanol for use as a biofuel, fermentation broth should be subjected to acetic acid removal step and the recovered acetic acid can be put to industrial use. Herein, batch LLE experiments were carried out at $25^{\circ}C$ using a synthetic fermentation broth comprising $20.0g\;l^{-1}$ acetic acid and $5.0g\;l^{-1}$ ethanol. Ethyl acetate (EtOAc), tri-n-octylphosphine oxide (TOPO), tri-n-octylamine (TOA), and tri-n-alkylphosphine oxide (TAPO) were utilized as solvents, and the extraction potential of each solvent was evaluated by varying the organic phase-to-aqueous phase ratios as 0.2, 0.5, 1.0, 2.0, and 4.0. The highest acetic acid extraction yield was achieved with TAPO; however, the lowest ethanol-to-acetic acid extraction ratio was obtained using TOPO. In a single-stage batch extraction, 97.0 % and 92.4 % of acetic acid could be extracted using TAPO and TOPO when the ratio of organic-to-aqueous phases is 4:1 respectively. A higher solvent-to-feed ratio resulted in an increase in the ethanol-to-acetic acid ratio, which decreased both acetic acid purity and acetic acid extraction yield.

• Korean Journal of Plant Taxonomy
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• v.45 no.3
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• pp.262-265
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• 2015

Two species of Syrrhopodon [S. japonicus (Besch.) Broth. and S. armatus Mitt.] were newly recorded from Jeju Island. S. japonicus was found on a rock covered with fine soil on the Che-oreum Volcano. This species is clearly distinguished from other species of the genus by its plants to 40 mm long, leaves bordered with several rows of short cells, and the margins at the leaf shoulders being regularly serrate. Syrrhopodon armatus was found on tree bark on Seopseom islet. It differs morphologically from other species of the genus in terms of its plant at 10 mm long, leaves bordered with one to several rows of linear and hyaline cells, leaves with spinous teeth at the shoulders. We propose new Korean names for these two species: 'Seon-o-reum-i-kki' and 'Jag-eun-seon-o-reum-i-kki,' respectively, which are based on their plant size and their first locations in Korea.

• Korean Journal of Veterinary Research
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• v.49 no.4
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• pp.335-343
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• 2009

The pathogenicity and acute toxicity of Lactobacillus (L.) pentosus PL11 from eel (Anguilla japonica) were investigated using male and female Sprague-Dawley rats. The pathogenicity of L. pentosus PL11 was examined after treating the rats with $10^{11}$ CFU/mL, $10^9$ CFU/mL or $10^7$ CFU/mL doses of L. pentosus PL11 culture or 0.85% NaCl (Control) intragastrically. For acute toxicity studies, rats were treated with dried culture broth of L. pentosus PL11 at doses of 5,000 mg/mL, 2,500 mg/mL, 1,250 mg/mL or 625 mg/mL or Lactobacilli MRS broth (Control), and clinical signs or mortalities were monitored for two weeks. The results of the present investigation revealed no mortalities or obvious clinical signs in rats administered with the live bacterial cultures or dried culture broth at any investigated dose level. Also, no significant differences were observed in net body weight gain, gross pathological findings, feed and water consumption and body temperature among the different treatment groups and between the treated and control rats. It can be concluded from the above findings that L. pentosus PL11 is a safe probiotic strain with potential as feed additive to increase the feed efficiency or health of fish.

• Food Science and Preservation
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• v.5 no.3
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• pp.286-291
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• 1998

The sensitivity of various pathogenic bacteria(Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus 196E, Salmonella typhimurium) to the water extract of green tea was tested. Tryptic soy broth was inoculated with 10$\^$5/CPU/ml of pathogenic bacteria and incubated at 35$^{\circ}C$ for 30 hours. The extract was added at a final concentration of 0-2%(w/v) into culture broth at the mid or late exponential phase of bacteria. The growth of pathogenic bacteria was inhibited with increasing concentrations of the extract in culture broth and the late exponential phase cells were more resistant than the mid exponential phase cells. Cram positive bacteria(L. monocytogenes and S. aureus 196E) were more sensitive than Cram negative bacteria(E. coli O157:H7 and S. typhimurium). S. aureus had the highest sensitivity, followed by L monocytogenes, E. coli O157:H7. S. typhimurium was the most resistant to the water extract of green tea.

• Food Science of Animal Resources
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• v.34 no.4
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• pp.448-456
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• 2014

Studies on the flavour characteristics of meat-based broth, quantification of flavour-related and functional compounds, and factors affecting the availability of such compounds are minimal. The present study was designed to determine the effects of sex on flavor-related and functional compounds in freeze-dried broth (FDB) made from Korean native chickens (KNC). Male and female KNC from a commercial strain (Woorimatdag$^{TM}$) were reared under similar commercial conditions. FDB was separately prepared using male and female birds aged 100 d (six birds of each sex) and analyzed for nucleotide, free amino acid, betaine, carnitine, carnosine, anserine, and creatine contents, and fatty acid composition. The levels of betaine, carnitine and creatine in FDB were not significantly different between the two sexes (p>0.05) in KNC. Carnosine and anserine were not detected in FDB samples. However, FDB from female chickens had significantly higher inosine-5-monophosphate and arachidonic acid contents than did FDB from male chickens. FDB prepared with male KNC contained higher levels of inosine, linoleic acid, glycine, alanine, lysine, and serine (p<0.05). However, glutamic acid, oleic acid, and DHA were present in comparable amounts (p>0.05) in FDB made from male and female KNC. Our findings suggest that the sex of KNC has significant effect on the contents of flavor-related compounds, but not functional compounds.

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.293-298
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• 2002

In order to investigate the ecological aspect of bacteria on groundwater, water samples were collected from various regions. Total of 318 strains were isolated from diluted nutrient broth (DNB) agar medium, and investigated their growth pattern on nutrient broth (NB) medium. As a result, all the isolated strains were divided into two groups, NB and DNB organisms. Growth of DNB organisms were suppressed in full strength NB medium but not in DNB medium, which were called oligotrophic bacteria in this study. Proportion of DNB organisms occurred in the frequency of 50-98% in potable groundwaters (CW, CJ, DPG, CJG1), however, it was 23,46% in polluted site (TJ, NPG1). One hundred and two strains were identified as oligotrophic bacteria and their phylogenetic characteristics were determined by using 16S rDNA sequencing. Based on the phylogenetic analysis, they were found to fall into three major phylogenetic groups: belonging to the Proteobacteria $\alpha$-(49 strains), $\beta$-(50 strains), $\gamma$ -(3 strains) subdivisions. The phylogenetic analysis suggested that microbial diversity of potable groundwater is more complex than that obtained in the past investigation.