• Title, Summary, Keyword: biofilm

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Effect of Sigma Factor ${\sigma}^{B}$ on Biofilm Formation of Listeria monocytogenes in High Osmotic and Low Temperature Conditions (고삼투압 및 저온 조건에서 sigma factor ${\sigma}^{B}$가 Listeria monocytogenes biofilm 생성에 미치는 영향)

  • Park, Sang-Gyu;Park, Shin
    • Korean Journal of Food Science and Technology
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    • v.36 no.3
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    • pp.456-460
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    • 2004
  • Effects of sigma factor (${\sigma}^{B}$) on biofilm formation in Listeria monocytogenes 10403S and ${\sigma}^{B}-deficient$ sigB null mutant were studied under high osmotic and low temperature conditions. In brain heart infusion (BHI) medium containing 6% NaCl, wild type 10403S and ${\sigma}^{B}-deficient$sigB null mutant formed biofilms of $6.83{\pm}0.38\;and\;5.33{\pm}0.45\;log\;cfu/cm^{2}$, respectively. L. monocytogenes 10403S in BHI medium containing 6% NaCl formed 4.7 times larger biofilm than without NaCl. Culture of L. monocytogenes 10403S and sigB null mutant at $4^{\circ}C$ did not show any significant differences in biofilm formation. The results suggest biofilm formation is activated by ${\sigma}^{B}$ and NaCl, whereas not affected by low temperature stress in L. monocytogenes 10403S. More studies are necessary to determine biofilm formation mechanism in osmotolerant L. monocytogenes.

Biocontrol of Biofilm-forming Bacillus cereus by Using Organic Acid, Ethanol, and Sodium Chloride (생물막 형성 Bacillus cereus에 대한 유기산, 에탄올 및 NaCl의 제어효과)

  • Lee, Young-Duck;Yoo, Hye-Lim;Park, Jong-Hyun
    • Korean Journal of Food Science and Technology
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    • v.45 no.1
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    • pp.120-125
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    • 2013
  • Food poisoning by Bacillus cereus is one of the common food-borne diseases and B. cereus is widely distributed in natural and commercial products owing to the strong resistance caused by biofilm or spore. The ethanol, NaCl, and organic acids of acetic acid, citric acid, and lactic acid for biocontrol of biofilm-forming B. cereus on glass wool were investigated. The biofilm on glass wool was observed in many developments after 48 h incubation. As the results of reduction of biofilm-forming B. cereus by sanitizers, reduction levels of each organic acid treatment ranged to 5-6 log CFU/g-glass wool. In case of combination treatments of 20% ethanol, 10% NaCl, and 1% of each organic acid for 1-5 min, the reduction level of biofilm-forming B. cereus was 7-8 log CFU/g-glass wool. Therefore, combination treatments of ethanol, NaCl, and an organic acid might effectively reduce biofilm-forming B. cereus in various food processes and industries.

Role of flgA for Flagellar Biosynthesis and Biofilm Formation of Campylobacter jejuni NCTC11168

  • Kim, Joo-Sung;Park, Changwon;Kim, Yun-Ji
    • Journal of Microbiology and Biotechnology
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    • v.25 no.11
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    • pp.1871-1879
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    • 2015
  • The complex roles of flagella in the pathogenesis of Campylobacter jejuni, a major cause of worldwide foodborne diarrheal disease, are important. Compared with the wild-type, an insertional mutation of the flgA gene (cj0769c) demonstrated significant decrease in the biofilm formation of C. jejuni NCTC11168 on major food contact surfaces, such as polystyrene, stainless steel, and borosilicate glass. The flgA mutant was completely devoid of flagella and non-motile whereas the wild-type displayed the full-length flagella and motility. In addition, the biofilm formation of the wild-type was inversely dependent on the viscosity of the media. These results support that flagellar-mediated motility plays a significant role in the biofilm formation of C. jejuni NCTC11168. Moreover, our adhesion assay suggests that it plays an important role during biofilm maturation after initial attachment. Furthermore, C. jejuni NCTC11168 wild-type formed biofilm with a net-like structure of extracellular fiber-like material, but such a structure was significantly reduced in the biofilm of the flgA mutant. It supports that the extracellular fiber-like material may play a significant role in the biofilm formation of C. jejuni. This study demonstrated that flgA is essential for flagellar biosynthesis and motility, and plays a significant role in the biofilm formation of C. jejuni NCTC11168.

THE EFFECT OF OXYGEN ON PERCHLORATE REDUCTION IN A BIOFILM REACTOR

  • Choi, Hyeok-Sun
    • Environmental Engineering Research
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    • v.12 no.4
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    • pp.148-154
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    • 2007
  • The purpose of this research was to investigate the effects of low concentration of oxygen on reduction of perchlorate, especially low perchlorate influent concentrations in a biofilm reactor, as well as the effect of flow pattern in a biofilm reactor. Dissolved oxygen averaging 1 mg/L did not inhibit reduction of influent perchlorate from 23 to $426\;{\mu}g/L$ in the biofilm reactors when sufficient acetate was added, probably due to limitation of oxygen diffusion into the biofilm. Influent perchlorate ranging from 23 to $426\;{\mu}g/L$ was reduced to below detection level ($4\;{\mu}g/L$) in the presence of 1 mg/L dissolved oxygen (DO). Chloride was produced in a ratio of $0.37gCl^-/g{ClO_4}^-$ and $0.35gCl^-/g{ClO_4}^-$ in plug flow and recirculation biofilm reactor which is similar to stoichiometric amount ($0.36gCl^-/g{ClO_4}^-$) indicating complete perchlorate reduction at $426\;{\mu}g/L$ of ${ClO_4}^-$ feeding. At $23\;{\mu}g/L$L influent perchlorate, total biomass solids were 3.18 g and 2.81 g in the plug flow and recirculation biofilm reactors. The most probable number(MPN) analysis for perchlorate-reducing bacteria showed $10^4$ to $10^5\;cells/cm^2$ in both biofilm reactors throughout the experiments. The effluent perchlorate concentrations were not significantly different in the two different flow regimes, plug flow and recirculation biofilm reactors.

Impact of the Isolation Source on the Biofilm Formation Characteristics of Bacillus cereus

  • Hussain, Mohammad Shakhawat;Oh, Deog-Hwan
    • Journal of Microbiology and Biotechnology
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    • v.28 no.1
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    • pp.77-86
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    • 2018
  • The human pathogen and food spoiler Bacillus cereus can form biofilms that act as a persistent source of contamination, which is of public health concern. This study aimed to understand how the source of isolation might affect the behavior of biofilm formation. Biofilm formation abilities of 56 strains of B. cereus isolated from different environments, including human food poisoning, farm, and food, were determined. Crystal violet assay results revealed significant (p < 0.05) differences in biofilm formation abilities among the strains isolated from different sources only at an early stage of incubation. However, strain origin showed no impact on later stage of biofilm formation. Next, correlation of the group of isolates on the basis of their biofilm-forming abilities with the number of sessile cells, sporulation, and extracellular polymeric substance (EPS) formation was determined. The number of sessile cells and spores in biofilms was greatly influenced by the groups of isolates that formed dense, moderate, and weak biofilms. The contribution of extracellular DNA and/or proteins to EPS formation was also positively correlated with biofilm formation abilities. Our results that the source of isolation had significant impact on biofilm formation might provide important information to develop strategies to control B. cereus biofilm formation.

A Study of Substrate Removal in Wastewater Flow Variations by Submerged Biofilm Reactor (浸漬型 生物膜反應槽에 의한 負荷變動에서의 基質除去에 관한 연구)

  • Nam, Chul-Hyun;Park, Jong-Woong
    • Journal of Environmental Health Sciences
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    • v.13 no.2
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    • pp.83-90
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    • 1987
  • The objective of this study is to review the basic theories related substrate removal in wastewater flow variations using submerged biofilm reactor. An aerated biofilm reactor is that in which influent organic substrates are aerobically oxidized by the microorganisms of biofilm grown on the surface of submerged media. No sludge is returned, and oxygen is supplied by diffusers. Three types of aerated biofilm reactor are one stage-central aeration, one stageup flow aeration and two stage-side aeration. The orders of substrate removal capacity in wastewater flow variations showed two stage-side aeration, one stage-upflow aeration and one stage-central aeration. The phenonmenon of nonclosing volid in upflow aeration type was superior to these in central-side aeration type. Attached biofilm masses in case of upflow, side and central aeration reactor were 1.0mg/cm$^2$, 4.1 mg/cm$^2$ and 0.93 mg/cm$^2$, respectively. Yield coefficient for biofilm was 0.31 to 0.48. Especially, removal efficiency can be increased remarkably according to the number of biofilm reactor and the packed condition of media.

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Microscope Examination of Attached Biofilm under Anaerobic Conditions (혐기성 조건에서 담체에 부착된 미생물의 관찰)

  • 박성열;김도한;나영수;박영식;송승구
    • Journal of Environmental Health Sciences
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    • v.27 no.1
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    • pp.100-105
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    • 2001
  • Microstructural examinations were performed on the anaerobic biofilm from reactor filled with PE support media. Optical microscope, SEM and fluorescent microscope were used for qualitative and morphological studies on the attached microorganism under anaerobic condition. Microorganisms were attached in crevices where protection from shear forces of surfaces where easy to contact with support media surface. A hypothesis for biofilm accumulation occurs on a surface such as polymer support media is presented schematically : 1st step ; cell-support media attachment, 2nd step ; cell-support media attachment and cell-cell attachment, 3rd step ; attached biofilm from neighboring crevices joins together and growing, 4th step ; mature and irregualar biofilm was formed. In SEM photographs, shape and structures of biofilm were observed, but microorganism species and methanogens were not identified. A large number of methanogenic bacteria were identified on the surface of PE substratum by fluorescence under 480nm of radiation and it was estimated that methanogenic bacteria was related to initial attachment of bacteria under anaerobic condition.

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Inhibitory Effect of Pentose on Biofilm Formation by Oral Bacteria

  • Lee, Young-Jong;Baek, Dong-Heon
    • International Journal of Oral Biology
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    • v.35 no.4
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    • pp.203-207
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    • 2010
  • A number of bacterial species coexist in oral cavities as a biofilm rather than a planktonic arrangement. By forming an oral biofilm with quorum sensing properties, microorganisms can develop a higher pathogenic potential and stronger resistance to the host immune system and antibiotics. Hence, the inhibition of biofilm formation has become a major research issue for the future prevention and treatment of oral diseases. In this study, we investigated the effects of pentose on biofilm formation and phenotypic changes using wild type oral bacteria obtained from healthy human saliva. D-ribose and D-arabinose were found to inhibit biofilm formation, but have no effects on the growth of each oral bacterium tested. Pentoses may thus be good candidate biofilm inhibitors without growth-inhibition activity and be employed for the future prevention or treatment of oral diseases.

A study on the treatment of highly-emulsified oily wastewater by an inverse fluidized-bed biofilm reactor (역 유동층 생물막 반응기를 이용한 유분함유폐수 처리에 관한 연구)

  • 최윤찬;나영수
    • Journal of Environmental Science International
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    • v.5 no.3
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    • pp.361-367
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    • 1996
  • An inverse fluidized-bed biofilm reactor (IFBBR) was used for the treatment of highly-emulsified oily wastewater. When the concentration of biomass which was cultivated in the synthetic wastewater reached to 6000 mg/1, the oily wastewater was employed to the reactor with a input COD concentration range of 50 mg/1 to 1900 mg/l. Virtually the IFBBR showed a high stability during the long operation period although soma fluctuation was observed. The COD removal efficiency was maintained over 9% under the condition that organic loading rate should be controlled under the value of 1.5 kgCOD/$m^3$/day, and F/M ratio is 1.0 kgCOD/kgVSS/day at $22{\circ}C$ and HRT of 12 hrs. As increasing organic loading rates, the biomass concentration was decreased steadily with decreasing of biofilm dry density rather than biofilm thickness. Based on the experimental jesuits, it was suggested that the decrease in biofilm dry density was caused by a loss of biomass inside the biofilm.

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Anti-Biofilm Activities of Manuka Honey against Escherichia coli O157:H7

  • Kim, Su-Yeon;Kang, Seok-Seong
    • Food Science of Animal Resources
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    • v.40 no.4
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    • pp.668-674
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    • 2020
  • Manuka honey (MH) has been shown anti-bacterial activity against several pathogenic bacteria. However, the inhibitory effect of MH on biofilm formation by Escherichia coli O157:H7 has not yet been examined. In this study, MH significantly reduced E. coli O157:H7 biofilm. Moreover, pre- and post-treatment with MH also significantly reduced E. coli O157:H7 biofilm. Cellular metabolic activities exhibited that the viability of E. coli O157:H7 biofilm cells was reduced in the presence of MH. Further, colony forming unit of MH-treated E. coli O157:H7 biofilm was significantly reduced by over 70%. Collectively, this study suggests the potential of anti-biofilm properties of MH which could be applied to control E. coli O157:H7.