• Microbiology and Biotechnology Letters
• /
• v.29 no.1
• /
• pp.56-61
• /
• 2001

For the development of probiotics in aquaculture of marine organisms, three strains having psychrophilic and salt tolerant characteristics were isolated from Kimchi. Amng the isolated strains. MG19, MG89 and MG208 were identified as Lactobacillus brevis, Enterococcus faecium and Lactobacillus plantarum, respectively. The neutralized culture broth of isolated strains were tested in order to evaluate the antibactrial activity, 조초 showed high antibacterial activity against Edwardsiella tarda, Vibrio cholerae andPseudomonas fluorescens. In mixed culture of pathogens and isolated strain,pathogens were signifi-cantly inhibited after 2 days of cultivation but the isolated strains showed normal growth. When the Edwardsiella tarda was cultured with three isolated strains, its growth was completely inhibited after 254 hours of cultivation. The effect of isolated three strains as probiotics was investigated based on the changes in body weight of aquacultured flounder. After 50 days feeding trial, it was found that the mean body weight gain of the tested group fed freeze-dried isolated cells was significantly greater than that of the control group. These results suggest that these isolated strains can play an important role as probiotics in aquaculture.

• Applied Biological Chemistry
• /
• v.36 no.5
• /
• pp.352-357
• /
• 1993

The effects of culture broth filtrates, sugar changes and utilizationon the growth and acid production of P. freudenreichii KFCC 31227and L. acidophilus KFCC 32825 were investigated in S.G.Y.(Skim milk, glucose, yeast extract) and SMW (skin milk whey)medium by the single and mixed cultures. The growth and acid production by mixed culture and in cultured broth filtrate of the other party were more affected than those of single culture and self-cultured broth filtrate. When the two strains were cultured, P. freudenreichii KFCC 31227 utilized with lactose more than glucose and L. acidophilus KFCC 32825 was glucose more than lactose in the growth and acid production. The mixed culture of two strains was more affected to sugar utilization than single culture. This result was considered due to the synergistic effect by interaction of these two strains in mixed culture.

• Microbiology and Biotechnology Letters
• /
• v.18 no.6
• /
• pp.607-612
• /
• 1990

The biodegradation of Aroclor 1242 was investigated by the mixed cultivation of the natural bacterial isolates and a genetically engineered microorganism (GEM). The natural strain of MS-1003 degraded the Aroclor 1242 through the ortho-cleavage pathway, while the other strains through the meta-cleavage pathway. When the MS-1003 strain was additionally inoculated into the 1 day culture of the DJ-26 strain and then cultivated for 2 days, the Aroclor was degraded up to 86% and resulted in increase of the meta-cleavage product. But in the MS-1003 culture inoculated with the DJ-26, degradation of the Aroclor was limited to the level of each pure culture. By the mixed cultivation of the DJ-26 strain together with the DJ-12 or its GEM strain of DF-10, which degrades the Aroclor through the meta-cleavage pathway, degradation of the Aroclor as well as production of the meta-cleavage compound were lower than those of each pure culture. The degradation of Aroclor 1242 by the GEM strain was not improved over the parental strain. Therefore, a form of cometaboiism of Aroclor 1242 was found in the mixed culture of the DJ-26 and MS-1003 strains which degrade the Aroclor through the different metabolic pathway, but in the mixed culture of the DJ-26 and DJ-12 strains degrading Aroclor 1242 through the same pathway, a kind of competetion for the substrate was observed.

• Transactions of the Korean hydrogen and new energy society
• /
• v.32 no.6
• /
• pp.506-513
• /
• 2021

The use of fossil fuels is a major contributor to the increase atmospheric greenhouse gas emissions. As such problems arise, interest in new and renewable energy devices, particularly fuel cells, is greatly increasing. In this study, various characteristics of mixed strains were observed in wastewater collected by the Jeonju Environment Office to investigate the effects of microorganisms on voltage generation and voltage generation of substrates, electrode materials, electrons, electron transport media, and ash microbial fuel cells. As a result of separately measuring the voltage generated during inoculation, the inoculation voltage of Escherichia coli K12 (E. coli K12) was 0.45 V, and the maximum inoculation voltage of the mixed strain was 1.2 V. Thereafter, voltage values were collected using a digital multimeter and the amount of voltage generated over time was measured. In the case of E. coli K12, the maximum voltage reached 0.45 V, and the cell voltage was maintained above 0.23 V for 140 hours. In contrast, for the mixed strain, the maximum voltage reached 1.2 V and the voltage was slowly decreased to 0.97 V. In addition, the degree of microbial adsorption to the electrod surface after the inoculation test was confirmed using a scanning electron microscope. Therefore, these results showed the possibility of purifying pollutants at the same time as power generation through the production of hydrogen ions using microorganisms and wastewater.

• Journal of Environmental Health Sciences
• /
• v.24 no.3
• /
• pp.70-76
• /
• 1998

Activation bacteria, identified from commercial microbial products, were applied to leachate treatment. Total seven strains of bacteria Enterobacteriaceae spp. (5), Bacillus sp. (1), Aeromonas sp. (1) were seeded in the leachate and cultured in the shaking incubator at 25$^{\circ}$C and 250 rpm. While cultured, they were sampled in given time intervals and the removal rates of SS, COD, BOD, T-N.and T-P were measured an indicators of leachate treatment. Through the screening test, four of 7 strains of bacteria were considered to be effective and they were named as "effective group". The capability of leachate treatment was observed on three different groups of bacteria single, effctive, and total mixed. The result showed that the removal rates of COD and SS for the total mixed group were 64 and 71% respectively. BOD removal rate was reached nearly 99% by seeding of effective griup and removal rates of T-P and T-N were 83 and 82% respectively. However seeding of single strain was less effective than that of any mixed group in leachate treatment.

• KSBB Journal
• /
• v.13 no.1
• /
• pp.6-12
• /
• 1998

In order to produce xylitol from hemicellulose hydrolysate which is widely used as a substrate, the development of strain such as catabolite derepressed mutant is required. After treatment of Candida sp. with EMS, GM-17 and PM-34 as catabolite derepressed mutant were isolated from Candida guilliermondii and Candida parapsilosis, respectively. Mutant GM-17 and PM-34 simultaneously assimilated xylose and glucose during the fermentation. The specific xylose reductase and xylitol dehydrogenase activities of mutant strains were also higher than those of wild strains in glucose medium and mixed medium of glucose and xylose. The xylitol productivity and yield of mutant GM-17 and PM-34 were improved as compared to the wild types in the mixed medium. The xylitol productivity and yield of mutant GM-17 were 0.09 g/L·hr and 0.56 g-xylitol/g-xylose, and those of mutant PM-34 were 0.21 g/L·hr and 0.52 g-xylitol/g-xylose in the mixed medium, respectively.

• KSBB Journal
• /
• v.13 no.5
• /
• pp.483-490
• /
• 1998

Two unidentified methanotrophic strains (MM-white and MM-red) secreting soluble methane monooxygenase (sMMO) involved in thrichloroethylene biodegradation have been isolated from mixed methanotrophic consortium (MM) around Taejon area. Subsequently four methanotrophic strains were isolated from MM and named according to their color; white (MS-white), yellow (MS-yellow), pink (MS-pink) and reddish brown (MS-rbrown). All strains except MS-yellow which can take glucose as well as methane, metabolized methane as a sole carbon source. They all showed symbiotic behavior when methane was used as the sole carbon source. Optimum conditions of cell growth for MM were pH of 6.8 - 7.2, temperature of 29 - 32$^{\circ}C$, and gas flow rate of 6 (for methane), 40 (for air), and 4 ml/min (for carbon dioxide). The sMMO activity was expressed as naphthalene oxidation rate (${\mu}$mol/ mg protein/ hr). The sMMO activity for MM grown in flask culture with 1 ${\mu}$M of CuSO4 was 36, while it was 61 without copper. The activity for MM grown in the fermentor without CuSO4 was 1077, but is was 197 after reaction with 5 ppm of TCE. The methanotrophs showed significantly high sMMO activity despite the presence of 1 ${\mu}$M of CuSO4, although most of other strains already known could not express sMMO activity under this condition.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.99.2-99
• /
• 2003

An attempt was made to screen antifungal activities of Bacillus thuringiensis strains on various plant pathogens, Botryosphaeria dothidea, Diaporthe actinidiae, Botrytis cinerea, Glomerella cingulata, Colletorichum cocodes, Sclerotinia scierotiorum, Alternaria alternata, Helicobuidium mompa, Bipolaris coicis, Fusarium graminearum and Rhizoctosnia solani. Ten and forty-five strains of B. thuringiensis were isolated from animal feces in Korea and Japan, respectively. Inhibitory effects of the strains on the mycelial growth of the pathogens were examined on the mixed media of potato dextrose agar and nutrient agar. Approximately half of the strains inhibited the mycelial growth of one or more pathogens. Most of the pathogens were inhibited by any of the strains but Fusarium graminearum and Rhizoctonia solani were not inhibited at all. This is the first report that B. thuringiensis shows a potent antifungal activity on plant pathogens in Korea.

• Korean Journal of Microbiology
• /
• v.52 no.1
• /
• pp.25-31
• /
• 2016

An enterococci selective medium was developed to detect the presence of enterococci for use as a fecal contamination indicator. Among several media which have been known to detect enterococci, the following 9 different kinds of media were selected: Enterococci Confirmatory agar, Azide dextrose agar, Bromocresol-purple azide agar, Esculin bile agar, Citrate azide tween carbonate agar, KF Streptococcus agar, BROLACIN agar, Kanamycin esculin azide agar, and Membrane filter Enterococcus selective agar. Various components from the nine media were mixed to develop a more effective enterococcus selective medium. The newly developed medium named as 'Enterococcus Mixed medium' was more effective than the previous 9 media. Enterococci strains (Enterococcus avium KACC 10788, Enterococcus faecium KACC 11954, Enterococcus saccharolyticus KACC 10783, Enterococcus durans KACC 10787, Enterococcus faecalis KACC 11304, and Enterococcus hirae KACC 10779) and non-enterococci strains (Escherichia coli KACC 10005, Staphylococcus aureus subsp. aureus KACC 10768, and Bacillus subtilis KACC 10111) were used to test the new medium. As a result, the enterococci strains grew well on the Enterococcus Mixed medium whereas the non-enterococci strains did not grow well on it. Additionally, growth of enterococci with freshwater and seawater samples was observed to be good on the Enterococcus Mixed medium. The result of this study confirmed that the Enterococcus Mixed medium was effective in detecting the target enterococci.

• KSBB Journal
• /
• v.27 no.6
• /
• pp.335-340
• /
• 2012

The microalgae, Microcystis aeruginosa are able to proliferate in a wide range of freshwater ecosystem. M. aeruginosa was cultivated in 25 L and 240 L race-way reactor containing modified medium with added urea 0.2 g/L, increased $Fe^{+2}$, and decreased $Ca^{+2}$ion compared to BG11 medium. Sugar contents of M. aeruginosa grown in BG11 medium, and modified medium were 120 mg/mL and 140 mg/mL respectively. Fermentation was conducted with the extract of M. aeruginosa at $30^{\circ}C$ for 30 h, using Saccharomyces cerevisiae (Sc), Pichia stipitis (Ps), Zymomonas mobilis (Zm), and mixed-culture of these strains (Sc + Ps + Zm). Pichia stipitis (0.7%) was found to be more suitable for producing bioalcohol from M. aeruginosa extract than other strains of Saccharomyces cerevisiae (0.45%) and Zymomonas mobilis (0.61%), while mixed-cultured of these strains showed higest productivity by 1.75%. Biomass of M. aeruginosa contains the potency to be the most renewable resource for bioalcohol fermentation.