• Korean Journal of Microbiology
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• v.51 no.3
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• pp.288-299
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• 2015

Lactobacillus brevis BK11 obtained from Baikkimchi was selected to study the effects of culture medium, initial pH, atmosphere composition, incubation temperature and time, and prebiotics on growth and production of antimicrobial substances. Growth and antimicrobial substances production of L. brevis BK11 were significantly higher in MRS broth than in BHI or M17 broth. The production of cell mass, lactic acid, and bacteriocin by BK11 strain was at maximum in MRS broth adjusted to pH 6.0. Aerobic and microaerobic conditions were favored cell growth and antimicrobial substances production than anaerobic condition. Biomass and lactic acid production and antimicrobial substances activity of BK 11 were significantly better at 30 and $37^{\circ}C$ than at $25^{\circ}C$. Growth of the strain BK11 entered the stationary growth stage at 24 h after inoculation, and decreased after 36 h. Antimicrobial activities of cell-free culture supernatant and bacteriocin solution were highest when cultured in MRS broth with an initial pH 6.0 for 24-30 h at $37^{\circ}C$. In addition, the highest cell number and lactic acid and bacteriocin production were recorded in the presence of 1 and 2% (w/v) fructooligosaccharide (FOS), however, inulin and raffinose did not affect biological and physicochemical characteristics and antimicrobial activities of L. brevis BK11 cultures. According to these results, production of antimicrobial substances by L. brevis KB11 was closely associated with cell density. Under optimal conditions for antimicrobial substances production, L. brevis BK11 effectively inhibited the growth of Helicobacter pylori ATCC 43504.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.142-147
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• 1993

For the purpose of fixing solar energy and utilizing water wastes from food industries for SCP(single cell protein), 170 strains of photosynthetic bacteria were isolated from 56 samples. Among 170 strains, B-Ps-106 strain was selected as the most suitable strain and identified as a variant or a relation of Rhodopseudomonas sphaeroides and its growth was better under anaerobic light condition than aerobic condition. The optimum conditions of the cell growth of B-Ps-106 were investigated on soybean-curd whey media. The optimum pH for cell growth was $8.5{\sim}9.0$. The optimum temperature was $30^{\circ}C$ and the optimum light density was above $0.72\;cal/cm^2/min$. The most favorable concentration of $K_2HPO_4\;and\;(NH_4)_2SO_4$ was both 0.9 g/l when added to soybean-curd whey media.

• Journal of Veterinary Clinics
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• v.28 no.5
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• pp.516-518
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• 2011

A survey was conducted to examine the normal intestinal bacterial flora of captive Oriental white storks (Ciconia boyciana) maintained at the Korea Institute of Oriental White Stork Rehabilitation Research, Cheongwon, South Korea. From the cloaca of 44 healthy storks, 44 fecal samples were collected and cultured under aerobic and anaerobic conditions. The 16S ribosomal RNA gene sequences and the heat shock protein 60 gene were cloned and sequenced for bacterial identification. Under aerobic conditions, Enterococcus faecalis, Escherichia coli, Bacillus spp., Enterococcus avium, Enterococcus gallinarum, Pseudomonas spp., Alcaligenes spp., Enterobacter spp., Corynebacterium spp., and Proteus mirabilis were identified. Under anaerobic conditions, E. coli, Clostridium tertium, En. faecalis, and P. mirabilis were identified. E. coli, En. faecalis, or both were isolated from all samples. These results will add to the information available on this stork species and help for the interpretation of fecal culture results.

• KSBB Journal
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• v.20 no.2 s.91
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• pp.116-122
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• 2005

The feasibility of using bacterial cultures with the ultimate aim for the marine environmental clean-up was explored. The present study reports on the bacterial elimination of nitrogens and phosphorus by strains CK-10 and CK-13 isolated from shrimp farming pond. The strains were identified as genus Bacillus on the basis of BIOLOG test, and designated as Bacillus sp. CK-10 and Bacillus sp. CK-13, respectively. Removal of nitrogens $(NH_4^+,\;NO_2^-,\;or\;NO_3^-)$ or phosphorus $(PO_4^{-3})$ as single N or P source was studied with single cultures under aerobic conditions. Complete elimination of all nitrogens in the concentration range of $100-400{\mu}M$ was achieved in single cultures as well as co-cultures within the given incubation period. Similar results were obtained from the test cultures containing $125-599{\mu}M\;PO_4^{3-}$. Simultaneous removal of all N/P was monitored in the co-cultures. As the results, $400{\mu}M\;NH_4^+\;and\;NO_2^-$ were eliminated within 12hrs and $400{\mu}M\;NO_3^-\;and\;500{\mu}M\;PO_4^{-3}$ were completely disappeared within 36 hrs from the media. The work demonstrated that co-cultures improved the concurrent removal of N/P from the media.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.1
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• pp.49-55
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• 2001

For the production of probiotic feed enriched with viable yeasts, aerobic liquid culture of Kluyveromyces marxianus was attempted in pulverized residual food wastes. After the preliminary shaking culture result, the liquid food wastes was added with urea($0.5g/{\ell}$), o-phosphate($0.4g/{\ell}$ ), molasses($4g/{\ell}$), and yeast extract($1g/{\ell}$), and the fermentation was carried out in 2-litre jar fermenter. In 12 hours of aerobic mixed culture with Aspersillus oryzae, viable cell count of the yeast reached to the number of $1.4{\times}10^{10}/{\ell}$ in the cultured medium.

• Applied Biological Chemistry
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• v.25 no.3
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• pp.126-134
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• 1982

When $^{14}C-2$, 6-Diethylaniline (2, 6-DEA) was incubated aerobically in soil, $^{14}CO_2$ evolved from non-sterile soil A and B was 6.5 and 10.1%, respectively, in the 21st week. Methanol could extract 3.1 and 13.5% of the radioactivity from soil A and B, respectively, 2, 6-Diethylacetanilide was detected as a degradation product in soil. Chaetomium globosum produced 2, 6-diethyl-p-benzoquinone as a degradation product in pure culture. A possible pathway was proposed to include p-hydroxylation of 2, 6-DEA, formation of quinoneimine, and the subsequent hydrolysis with the release of ammonia.

• Clinical and Experimental Pediatrics
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• v.49 no.3
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• pp.268-272
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• 2006

Purpose : The reinfection rate of H. pylori reported before $^{13}C$-urea breath test($^{13}C$-UBT) era was higher than that of the post $^{13}C$-UBT era. Children are usually reluctant to receive invasive endoscopic evaluation for the reinfection of H. pylori, particularly when they are asymptomatic. The aim of the study is to discover the reinfection rate by different diagnostic tests, and to find out what causes the difference. Methods : Children confirmed to be eradicated from H. pylori were included in the study. Reinfection was evaluated by endoscopic biopsy based tests(n=34, mean age $11.5{\pm}3.7$ years) and/or a $^{13}C$-UBT(n=38, mean age $10.0{\pm}3.6$ years) at the time of 18 months after eradication. At first visit, H. pylori infection had been diagnosed by positive results from a rapid urease test, Giemsa stain and Warthin-Starry stain and/or a positive culture. Eradication was defined as negative results from all above tests 1-3 months after eradication therapy. Results : Reinfection rate by endoscopic biopsy based tests was 35.3 percent(12/34). All patients had abdominal symptoms(P=0.000). Reinfection rate was 13.2 percent(5/38) by a $^{13}C$-UBT. Reinfection rate was higher in children with abdominal symptoms(P=0.008). There was no evidence that reinfection rate depended on the sex(P=0.694), age(P=0.827), diseases(peptic ulcers vs gastritis, P=0.730) and eradication regimen(P=0.087). Conclusion : Helocibacter pylori reinfection rate in Korean children was 13.2 percent per 18 months by a non-invasive test or $^{13}C$-UBT. Accurate determinations of the reinfection rate in children is affected by the compliance of the diagnostic tests. Non-invasive tests should be considered to investigate the reinfection rate in children.

• KSBB Journal
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• v.10 no.5
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• pp.561-567
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• 1995

Using superoxide dismutase (SOD)-deficient mutants of Saccharomyces cerevisiae, the oxygen toxicity induced by paraquat was studied. In aerobic culture condition, yeasts lacking MnSOD (milochondrial SOD) showed more significant growth retardation than CuZnSOD (cytoplasmic SOD)-deficient yeasts. However, not so big differences in growth pattern of those mutants compared with wild type were observed under anaerobic condition. When exposed to paraquat, the growth of yeasts lacking CuZnSOD was severely affected by higher than 0.01mM of paraquat in culture medium. By the analysis of several cellular components ivolved in free radical generating and scavenging system, it was found that, under aerobic condition, the content of lipid peroxides in cell membrane as well as cellular activity of glutathion peroxidase of CuZnSOD-deficient mutants was increased in the presence of paraquat, although significant decrease of catalase activity was observed in those stratns. In MnSOD-deficient yeast, however, increment in cellular activity of glutathion peroxldase and catalase by paraquat was observed without any deterioration of membrane lipid. It implies that the lack of mitochondrial SOD could be compensated by both of glutathion peroxldase and catalase, but that only glutathion peroxidase might act for CuZnSOD in cytoplasm. In contrast, all of SOD-deficient mutants showed a significant decrease in catalase activity, but slight increase in the activities of glutathion peroxidase, when cultivated anaerobically in the medium containing paraquat. Nevertheless, any significant changes of lipid peroxides in cell membranes were not observed during anaerobic cultivation of SOD-deficient mutants. It suggests that a little amount of free radicals generated by paraquat under anaerobic condition could be sufficiently overcome by glutathion peroxidase but not by catalase.

• Journal of Life Science
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• v.28 no.8
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• pp.969-976
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• 2018

In this study, transglucosidase (TG), an enzyme produced by Aspergillus niger, synthesized isomaltooligosaccharide from ${\alpha}-(1{\rightarrow}4)$ linked substrates. The highest TG-producing A. niger KCTC6913 was selected from six kinds of species, and optimized TG producing conditions were established. Five different carbon sources (potato starch, sweet potato starch, corn starch, wheat starch, and dextrin) and three different nitrogen sources (yeast extract, malt extract, and beef extract) were tested to establish the carbon and nitrogen sources favorable for TG production. Measurements of TG activity after an initial culture at pH 5.0 for 15 days revealed that potato starch and yeast extract, which are basic culture media, resulted in the highest TG activity. In addition, A. niger KCTC6913 increased TG production under aerobic conditions and a controlled carbon/nitrogen ratio. In conclusion, to evaluate TG activity in the established optimal medium, it is confirmed that the basal and potato dextrose broth medium were used as a control, and the highest TG production was measured, which was highlighted in the established optimal medium.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.343-347
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• 1997

Effect of culture conditions on the fermentation of wheat flour solution by mixed lactic acid bacteria of Lactobacillus brevis, L. fermentum and L. plantarum was investigated. The optimum temperature for the fermentation of wheat flour solution was $35^{\circ}C$ because pH decreased the lowest value and TTA (total titrable acidity) increased the highest value at this temperature. In aerobic condition, fermentor was purged with air at 1.0 vvm and was purged with nitrogen gas at 1.0 vvm in anaerobic condition. The decrease of pH and the increase of TTA in aerobic condition were higher than those in anaerobic condition. In aerobic condition, the optimum condition of oxygen supply was found to be oxygen transfer rate coefficient of $60\;hr^{-1}$ which corresponded to agitation speed of 250 rpm in a 5 L fermentor. Repeated fed-batch cultures were performed using pH-stat in order to increase the productivity of fermented wheat flour. With increasing the repeated fraction of culture volume, mean cycle time increased but maximum operation time decreased. However, the volume of produced broth per culture volume per time and total volume of produced broth per culture volume were maximum at the repeated fraction of culture volume of 20%. In a repeated fed-batch fermentation of wheat flour solution using mixed lactic acid bacteria, the culture condition was optimum at temerature of $35^{\circ}C$, aeration rate of 1.0 vvm, oxygen transfer rate coefficient of $60\;hr^{-1}$, and repeated fraction of culture volume of 20%.