• Title, Summary, Keyword: biofilm

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Screening of Anti-Biofilm Compounds from Marine-Derived Fungi and the Effects of Secalonic Acid D on Staphylococcus aureus Biofilm

  • Wang, Jie;Nong, Xu-Hua;Zhang, Xiao-Yong;Xu, Xin-Ya;Amin, Muhammad;Qi, Shu-Hua
    • Journal of Microbiology and Biotechnology
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    • v.27 no.6
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    • pp.1078-1089
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    • 2017
  • Biofilm formation of Staphylococcus aureus is one of its mechanisms of drug resistance. Anti-biofilm screening of 106 compounds from marine-derived fungi displayed that 12 compounds inhibited S. aureus biofilm formation by >50% at the concentration of $100{\mu}g/ml$, and only secalonic acid D (SAD) and B inhibited by >90% at $6.25{\mu}g/ml$ without inhibiting cell growth after 24-h incubation. Meanwhile, it was found that the double bond between C-1 and C-10 of citrinin derivatives and the C-C connection position of two chromone monomers may be important for their anti-biofilm activities. Moreover, SAD slightly facilitated biofilm eradication and influenced its architecture. Furthermore, SAD slowed the cell growth rate in the preceding 18-h incubation and differentially regulated transcriptional expression of several genes, such as agr, isaA, icaA, and icaD, associated with biofilm formation in planktonic and biofilm cells, which may be the reason for the anti-biofilm activity of SAD. Finally, SAD acted synergistically against S. aureus growth and biofilm formation with other antibiotics. These findings indicated that various natural products from marine-derived fungi, such as SAD, could be used as a potential biofilm inhibitor against S. aureus.

Effect of Aeration Intensity on the Treatment Efficiency in Submerged Biofilm Process (침지형 생물막공법에 있어서 포기강도가 처리효율에 미치는 영향)

  • 박종웅
    • Journal of Environmental Health Sciences
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    • v.15 no.1
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    • pp.89-96
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    • 1989
  • An aerated submerged biofilm reactor is the reactor in which influent organic substrates are aerobically oxidized by suspended biomass and attached biomass of biofilm grown on the surface of submerged media. The objective of this study was to investigate the effect of aeration intensity on microbial characteristics and treatment efficiency in submerged biofilm process. In the organic loading rate (4.3kg BOD/$m^{3} \cdot day$), biofilm thickness (420-780$\mu$m) and attached biomass(1.79-2.94mg/cm$^{2}$) increased as the aeration intensity increased (2-8m$^{3}$ air/$m^{2} \cdot hr$), but biofilm density decreased (42.25-37.69mg/cm$^{3}$). The minimum aeration intensity for prevention of deposited biomass was 2m$^{3}$ air/$m^{2} \cdot hr$. The minimum dissolved oxygen of 2.5mg/l had to be maintained for improved efficiency.

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Nitrogen and Phosphorous Removal from Wastewater by SBBR(Sequencing Batch Biofilm Reactor) System (연속회분식 생물막 반응기를 이용한 폐수중의 질소.인 제거)

  • 김조웅;이정복;최대건;임윤택;김두현;황재웅;이용희;반용병
    • KSBB Journal
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    • v.13 no.6
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    • pp.638-643
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    • 1998
  • An investigation was made to develop new biofilm medium which could be applied to the Sequencing Batch Biofilm Reactor(SBBR) system for enhanced nutrient removal. 21 kinds of polyurethane media were tested fro adhesion ability for nitrifying bacteria. Nitrification rates were also tested by introducing synthetic wastewater containing ammonium-nitrogen to reactors with biofilm media. It was found that Z96-06 medium had higher selective adhension ability for nitrifying bacteria than the other biofilm media. The nitrification rate was 2.21 mg {{{{ { NH}`_{4 } ^{ +} }}}}-N /L$.$h$.$g MLSS when we operated the SBBR system containing Z96-06. Nitrification rate of the SBBR system increased approximately by 30% compared with that of the Sequencing Batch Reactor(SBR) system which did not contain biological carrier.

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Perchlorate Removal using Sewage in a Fixed Biofilm Reactor (하수를 이용한 고정생물막반응조에서 퍼클로레이트 제거)

  • Liao, Ziqiao;Choi, Hyeoksun
    • Journal of Korean Society of Water Science and Technology
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    • v.25 no.6
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    • pp.49-55
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    • 2017
  • The purpose of this research was to investigate whether domestic sewage as carbon substrates and nutrients can be used to reduce perchlorate in biological perchlorate treatment system. A fixed biofilm reactor was used to reduce perchlorate in sewage containing 4.41~7.65 mg/L perchlorate at various EBCT conditions such as 8hours, 4hours, and 2hours. 4.41 mg/L of perchlorate was reduced to 0.02 mg/L of perchorate which means 99.5% of perchlorate removal efficiency at 4hours of EBCT in a fixed biofilm reactor. Perchlorate and nitrate in sewage were reduced simultaneously at 4hours of EBCT in a fixed biofilm reactor. However, perchlorate removal efficiency decreased slightly in the presence of nitrate at 4hours EBCT in a fixed biofilm reactor compared to the previous experiment result in the absence of nitrate.

Safety Investigation of Tap Water and Biofilm by Isolated Bacteria (수돗물과 생물막의 세균분포를 통한 안전성 조사)

  • Lee, Dong-Geun
    • Journal of Environmental Health Sciences
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    • v.30 no.3
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    • pp.207-213
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    • 2004
  • For investigation of the food safety and influence of biofilm on the bacterial quality of tap water, it was detected by selective media, and identified by API kit and MIDI system. Biofilm and effluent showed much more colonies than influent. Although there were many presumptive positive colonies, no pathogenic bacterium detected. However opportunistic pathogens, such as Pseudomonas aeruginosa and Aeromonas species, and members of family Enterobacteriaceae were detected. Compared to influent, biofilm and effluent showed more diverse bacteria. This study implies that there would be the negative influence of biofilm on the bacterial qualities of tap water.

Effect of Cathodic Biofilm on the Performance of Air-Cathode Single Chamber Microbial Fuel Cells

  • Ahmed, Jalal;Kim, Sung-Hyun
    • Bulletin of the Korean Chemical Society
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    • v.32 no.10
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    • pp.3726-3729
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    • 2011
  • Biofilm formation is inevitable in a bioelectrochemical system in which microorganisms act as a sole biocatalyst. Cathodic biofilm (CBF) works as a double-edged sword in the performance of the air-cathode microbial fuel cells (MFCs). Proton and oxygen crossover through the CBF are limited by the robust structure of extracellular polymeric substances, composition of available constituents and environmental condition from which the biofilm is formed. The MFC performance in terms of power, current and coulombic efficiency is influenced by the nature and origin of CBF. Development of CBF from different ecological environment while keeping the same anode inoculums, contributes additional charge transfer resistance to the total internal resistance, with increase in coulombic efficiency at the expense of power reduction. This study demonstrates that MFC operation conditions need to be optimized on the choice of initial inoculum medium that leads to the biofilm formation on the air cathode.

Electrochemical Sensor for Detecting Underwater Biofilm Using Cyclicvoltammetry (순환전압전류법을 이용한 수중 생물막 측정 전기화학센서)

  • Hwang, Byeong-Jun;Lee, Sung-Ho
    • Journal of Sensor Science and Technology
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    • v.21 no.5
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    • pp.374-378
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    • 2012
  • Biofouling causes many problem in industrial processes, medical health industries, water utilities and our daily life. So detecting formation of biofilm on the surface of medical appliance, water pipe and industrial utility is highly important to prevent the problem caused by biofouling. In this study, we suggest an electrochemical sensor for detecting biofilm. We fabricated the electrochemical sensor in MEMS process and cultivated two different kinds of Pseudomonas aeruginosa RpoN type and Wild type on the surface of electrochemical sensor. Each group of Pseudomonas aeruginosa was cultivated according to the hours of 2, 4, 6, 8, 12 and 24. Then we investigated changes in degree of biofilm cultivation using cyclic voltammetry. As a result, it was observed that peak of the cyclic voltammetry curve is increased according as the biofilm growth on the surface of electrochemical sensor. Also we can discern between Pseudomonas aeruginosa RpoN type and Wild type.

Effect of the Liquid Circulation Velocity on the Biofilm Development in an IFBBR (역 유동층 생물막 반응기에서 액체순환속도가 생물막에 미치는 영향)

  • 김동석;윤준영
    • Journal of Environmental Science International
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    • v.3 no.1
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    • pp.49-56
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    • 1994
  • Effect of the liquid circulation velocity on the biofilm development was investigated in an inverse fluidized bed biofilm reactor(IFBBR). To observe the effect of the influent COD concentration on biofilm simultaneously, the influent COD value was adjusted to 1000mg/1 f for 1st reactor, and 2500mg/l for 2nd reactor. The liquid circulation velocity was adjusted by controlling the initial liquid height. As the liquid circulation velocity was decreased, the settling amount of biomass was increased and the amount of effluent biomass was decreased. Since the friction of liquid was decreased by the decrease of liquid circulation velocity, the biofilm thickness was increased and the biofilm dry density was decreased. In the 1st reactor the SCOD removal efficiency was constant regardless of the variation of the liquid circulation velocity, but it was increased by the decrease of the liquid circulation velocity because of more biomass population in 2nd reactor.

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Analysis of Effects of Factors Influencing Biofilm Formation in Drinking Water Distribution Pipe Using Factorial Experimental Design (요인실험계획을 이용한 수도관 생물막 형성 영향 인자의 효과 분석)

  • Park, Se-Keun;Choi, Sung-Chan;Kim, Yeong-Kwan
    • Journal of Korean Society of Water and Wastewater
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    • v.19 no.2
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    • pp.181-192
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    • 2005
  • This study evaluated the effect of factors influencing the initial biofilm formation in drinking water distribution pipe by running experiments using a $2^{4-1}$ fractional factorial experimental design with a replicate. Important variables used for assessing biofilm formation included BDOC(biodegradable dissolved organic carbon), viable heterotrophic bacteria present in drinking water, water temperature, and shear stress at two levels each. Based on the statistical analysis of biofilm levels measured as attached HPC(heterotrophic plate count) and community-level assay, the main factors that have significant effects on biofilm formation were found to be viable heterotrophic bacteria and BDOC. Water temperature only exhibited significant effect on the levels of attached HPC, while shear stress was not a significant factor under given conditions. Moreover, the statistical analysis revealed that interactions between the important variables were not statistically significant at a 0.05 significance level.

Endodontic biofilms: contemporary and future treatment options

  • Yoo, Yeon-Jee;Perinpanayagam, Hiran;Oh, Soram;Kim, A-Reum;Han, Seung-Hyun;Kum, Kee-Yeon
    • Restorative Dentistry and Endodontics
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    • v.44 no.1
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    • pp.7.1-7.10
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    • 2019
  • Apical periodontitis is a biofilm-mediated infection. The biofilm protects bacteria from host defenses and increase their resistance to intracanal disinfecting protocols. Understanding the virulence of these endodontic microbiota within biofilm is essential for the development of novel therapeutic procedures for intracanal disinfection. Both the disruption of biofilms and the killing of their bacteria are necessary to effectively treat apical periodontitis. Accordingly, a review of endodontic biofilm types, antimicrobial resistance mechanisms, and current and future therapeutic procedures for endodontic biofilm is provided.