• Title/Summary/Keyword: mixed-culture

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Biodegradation of Gasoline Oxygenate MTBE(Methyl tert-Butyl Ether) by Butane-Utilizing Bacteria (부탄분해미생물에 의한 가솔린첨가제 MTBE(Methyl tert-Butyl Ether) 분해)

  • 장순웅;백승식;이시진
    • Journal of Soil and Groundwater Environment
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    • v.6 no.3
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    • pp.31-41
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    • 2001
  • In this study, we have examined the potential degradation of MTBE(methyl tert-butyl ether) by pure culture ENV425 and mixed culture obtained from gasoline contaminated soil using n-butane as the sources of carbon and energy. The results described in this study suggest that MTBE is degraded cometabolically by ENV425 and mixed culture grown on n-butane. Butane and MTBE degradation was completely inhibited by acetylene, which indicated that both substrates were degraded by butane monooxygenase. These cultures grown on n-butane generated TBA (tert-butyl alcohol) as a metabolite of MTBE oxidation. TBA Production was accounted 54.7% and 58.6% for MTBE oxidation by ENV425 and mixed culture, respectively. In resting cell experiments, however, TBA and TBF were detected as the oxidation products of MTBE by ENV425 and mixed culture. The observed maximal MTBE degradation rates were 52.3 and 62.3 (nmol MTBE degraded/hr/mg TSS) by ENV425 and mixed culture, respectively, and the observed maximal transformation yields ($T_y$) were 44.7 and 34.0 (nmol MTBE degraded/$\mu$mol n-butane utilized), and the observed maximal transformation capacities ($T_c$) were 199 and 226 ($\mu$mol MTBE degraded/mg TSS used).

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Characteristics of Sourdough Bread Prepared using Bifidobacterium longum, Enterococcus faecium, and Lactobacillus acidophilus as a Combination Starter (Bifidobacterium longum-Enterococcus faecium-Lactobacillus acidophilus를 스타터로 사용하여 만든 sourdough bread 제조 및 품질특성)

  • Chae, Dong-Jin;Lee, Kwang-Suck;Jang, Ki-Hyo
    • Korean Journal of Food Preservation
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    • v.18 no.1
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    • pp.91-97
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    • 2011
  • The influence of two process parameters (starter and fermentation period) on sourdough bread qualities was investigated. Bifidobacterium longum/Enterococcus faecium/Lactobacillus acidophilus (a mixed culture) was used as a starter. The five production conditions tested were: Control (sourdough fermentation with yeast); LAB 1(fermentation with mixed culture); LAB 2 (fermentation with yeast and mixed culture, respectively); LAB 3 (fermentation with yeast and mixed culture); and LAB 4 (first fermentation with yeast and mixed culture, respectively, followed by a second fermentation using the combination). The LAB 4 process showed the most favorable fermentation characteristics upon CrumbScan analysis, and the highest specific bread volume (5.14 mL/g). These results were reflected in the sensory evaluation of bread produced by the LAB 4 process; the bread achieved an excellent overall acceptance ranking of 3.7. Upon firmness analysis, the LAB 2, LAB 3, and LAB 4 bread figures were 113.67 g, 111.97 g, and 113.50 g, respectively. Thus, the firmness of LAB 2, LAB 3, and LAB 4 bread was higher than that of the control (93.20 g), although the aroma compounds of bread produced by the five processes did not differ. These results show that LAB 4 bread had improved sourdough properties, compared to control.

Expression of ssrA in non-pathogen-induced adaptation in the oral cavity through signal exchange with oral pathogens

  • Kim, Sung-Ryoul;Kwak, Jae-Woo;Lee, Sung-Ka;Jung, Seung-Gon;Han, Man-Seung;Kim, Bang-Sin;Kook, Min-Suk;Oh, Hee-Kyun;Park, Hong-Ju
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.38 no.1
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    • pp.14-19
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    • 2012
  • Introduction: This study was conducted to evaluate ssrA expression resulting from adaptation of Escherichia coli (E. coli) to oral pathogens through signal exchange. Materials and Methods: Human cell lines Hep2 and HT29, wild-type E. coli (WT K-12), ssrA knock-out E. coli (${\Delta}K$-12), and Scleropages aureus (S. aureus) were used. A single culture consisting of Hep2, HT29, WT K-12, and ${\Delta}K$-12, and mixed cultures consisting of Hep2 and WT K-12, Hep2 and ${\Delta}K$-12, WT K-12 and S. aureus, ${\Delta}K$-12 and S. aureus, and Hep2, WT K-12, and S. aureus were prepared. For HT29, a mixed culture was prepared with WT K-12 and with WT K-12 and S. aureus. Total RNA was extracted from each culture with the resulting expression of ssrA, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-${\kappa}B$), and p53 was evaluated by Reverse transcription polymerase chain reaction (RT-PCR). Results: The expression of ssrA in a single culture of WT K-12 was lower than that observed in the mixed culture of WT K-12 with S. aureus. Greater ssrA expression was observed in the mixed culture of WT K-12 with Hep2 than in the single culture of WT K-12. The expression of NF-${\kappa}B$ was higher in the mixed culture of Hep2 with ${\Delta}K$-12 than that in the mixed culture of Hep2 with WT K-12, and was lowest in the single culture of Hep2. The expression of ssrA was higher in the mixed culture of WT K-12 with Hep2 and S. aureus than in the mixed culture of WT K-12 with Hep2. Conclusion: These results suggest that ssrA plays an important role in the mechanism of E. coli adaptation to a new environment.

Mixed Culture Fermentation of Steamed Barley by a Tri-Culture System (곰팡이, 효모 및 유산균에 의한 보리의 혼합발효)

  • Lee, Hyeong-Chun;Gu, Yeong-Jo;Sin, Dong-Hwa
    • The Korean Journal of Food And Nutrition
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    • v.1 no.2
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    • pp.56-63
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    • 1988
  • Fermented barley food was produced by the mixed culture fermentation with a tai-cults re system of a mold, a yeast and a lactobacillus. When Rhizopus delemar IFO 4746, Hansenular anomala IFO 0568 and Lactobacillus sp. L-5 were selected and cultivated on steamed barley at 3$0^{\circ}C$ for 2days and 37$^{\circ}C$ for 3days, the fermented product of good quality was obtained. During fermentation. changes in acidity, pH, water content and color of fermented barley were examined.

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Growth Characteristics and Optimal Culture Conditions of PVA-Degrading Strains (Polyvinyl Alcohol분해자화균의 성장특성과 최적 배양조건)

  • 김정목;조무환조윤래정선용
    • KSBB Journal
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    • v.6 no.4
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    • pp.363-368
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    • 1991
  • PVA degrading bacteria were isolated from water system, and identified as Pseudomonas cepacia and Pseudmonas pseudomallei, which were named as Pseudomonas sp. G5Y and Pseudomonas sp. PW. It was found out that those two kinds of bacteria have a symbiotic relationship to degrade PVA. For the mixed culture of these bacteria, the optimal conditions of pH, temperature, nitrogen source, and polymerization degree of PVA were found to be 7.5, $35^{\circ}C$, ammonium sulfate, and 500, respectively. Also, the growth of these bacteria was promoted by trace elements such as vitamin B1, B12, pyridoxine, and p-aminobenzoate, respectively. The specific growth rate of mixed bacteria was inhibited when the concentration of PVA was more than 20g/l. The substrate inhibition kinetics of the mixed culture was $${\mu}=\frac{0.065S}{2.56+S+(S^2/156}hr^{-1}$

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Characterization of BTX-degrading bacteria and identification of substrate interactions during their degradation

  • Oh, Young-Sook;Choi, Sung-Chan
    • Journal of Microbiology
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    • v.35 no.3
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    • pp.193-199
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    • 1997
  • From several industrial wastewaters, 14 bacterial strains which degrade benzene, toluene, o-xylene, m-xylene, or p-xylene (BTX) were obtained. These strains were characterized as to their species composition and the substrate range, kinetic parameters and the substrate interactions were investigated. Although BTX components have a similar chemical structure, isolated strains showed different substrate ranges and kinetic parameters. None of the strains could degrade all of BTX components and most of them showed an inhibition (Haldane) kinetics on BTX, BTX mixtures were removed under inhibitory substrate interactions with variation in the intensity of inhibition. For a complete degradation of BTX, a defined mixed culture containing three different types of patyways was constructed and all of the BTX components were simultaneously degraded with the totla removal rate of 225.69 mg/g biomass/h Judging from the results, the obtained mixed culture seems to be useful for the treatment of BTX-contaminated wastewater or groundwater as well as for the removal of BTX from the contaminated air stream.

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Kinetic Study of pH Effects on Biological Hydrogen Production by a Mixed Culture

  • Jun, Yoon-Sun;Yu, Seung-Ho;Ryu, Keun-Garp;Lee, Tae-Jin
    • Journal of Microbiology and Biotechnology
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    • v.18 no.6
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    • pp.1130-1135
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    • 2008
  • The effect of pH on anaerobic hydrogen production was investigated under various pH conditions ranging from pH 3 to 10. When the modified Gompertz equation was applied to the statistical analysis of the experimental data, the hydrogen production potential and specific hydrogen production rate at pH 5 were 1,182 ml and 112.5 ml/g biomass-h, respectively. In this experiment, the maximum theoretical hydrogen conversion ratio was 22.56%. The Haldane equation model was used to find the optimum pH for hydrogen production and the maximum specific hydrogen production rate. The optimum pH predicted by this model is 5.5 and the maximum specific hydrogen production rate is 119.6 ml/g VSS-h. These data fit well with the experimented data($r^2=0.98$).

Production of Acetate from Carbon Dioxide in Bioelectrochemical Systems Based on Autotrophic Mixed Culture

  • Su, Min;Jiang, Yong;Li, Daping
    • Journal of Microbiology and Biotechnology
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    • v.23 no.8
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    • pp.1140-1146
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    • 2013
  • Bioelectrochemical systems (BESs) have been suggested as a new technology for wastewater treatment while accomplishing energy and chemical generation. This study describes the performance of BESs based on mixed culture that are capable of reducing carbon dioxide to acetate. The cathode potential was a critical factor that affected the performance of the BESs. The rate of acetate production increased as the electrode potential became more negative, from 0.38 mM $d^{-1}$ (-900 mV vs. Ag/AgCl) to 2.35 mM $d^{-1}$ (-1,100 mV), while the electron recovery efficiency of carbon dioxide reduction to acetate increased from 53.6% to 89.5%. The microbial population was dominated by relatives of Acetobacterium woodii when a methanogenic inhibitor was added to the BESs initially.

Optimization of Bread Fermentation with Lactic Acid Bactria & Yeast Isolated from Kimchi (김치로부터 분리한 유산균과 효모 혼합 발효액의 제빵 최적화)

  • 신언환;정성제
    • Culinary science and hospitality research
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    • v.9 no.3
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    • pp.130-140
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    • 2003
  • The studies were carried out to optimize a new starter for bread fermentation. Two strains of lactic acid bacteria and yeast were isolated from Kimchi. These strains showed good condition for quality bread fermented. The strains identified as Leuconostoc mesenteroides, Lactobacillus brevis, Saccharomyces fermentati and Saccharomyces cerevisiae. The mixed culture of four strains was due to the synergistic effect by interaction of these strains.

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