scholarly journals Inhibitory Effect of Vanillin on Biofilm Formation by Multi-Species Wastewater Culture

2020 ◽  
Vol 23 (4) ◽  
pp. 274-279
Author(s):  
Xiurong Si ◽  
Ding Ding ◽  
Jianhua Zhou ◽  
Zhangwei Cao
Keyword(s):  
Membrane Fouling ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Inhibitory Effect ◽  
Inhibition Rate ◽  
Microbial Adhesion ◽  
Fouling Control ◽  
Microfluidic Chamber ◽  
Research Findings ◽  
Static Conditions

This paper mainly investigates the inhibitory effect and mechanism of vanillin on mixed-culture biofilm formation, and discusses the feasibility of controlling membrane fouling with vanillin. The biofilms were cultured under static conditions and a microfluidic chamber, respectively. The results show that vanillin can effectively inhibit the microbial adhesion and biofilm formation; the inhibition rate increases with the vanillin concentration. After 12h treatment with 300mg/L vanillin, the inhibition rate of biofilm formation reached 85.34%. Besides, vanillin can mitigate bacterial adhesion by reducing the microbial secretion of exoprotein and exopolysaccharide, exhibit an inhibitory effect on the expression of N-acyl-l-homoserine lactones (AHLs), but had no effect on environmental deoxyribonucleic acid (eDNA). After being treated with 300mg/L vanillin, exoprotein, exopolysaccharide and AHLs decreased by 28.48%, 17.23% and 46.64%, respectively. Furthermore, there is a positive correlation between the AHLs and the content of extracellular polymeric substances (EPSs); the AHLs-mediated quorum sensing (QS) might be related to microbial adhesion through the regulation of EPS. Finally, vanillin has a great potential in membrane fouling control. The research findings provide a good reference for biofilm control in water purification and wastewater treatment systems.

scholarly journals A Real-Time Thermal Sensor System for Quantifying the Inhibitory Effect of Antimicrobial Peptides on Bacterial Adhesion and Biofilm Formation

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2771
Author(s):  
Tobias Wieland ◽  
Julia Assmann ◽  
Astrid Bethe ◽  
Christian Fidelak ◽  
Helena Gmoser ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Real Time ◽  
Bacterial Adhesion ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Bovine Mastitis ◽  
Inhibitory Effect ◽  
Thermal Sensor ◽  
Bacterial Cells ◽  
Static Conditions

The increasing rate of antimicrobial resistance (AMR) in pathogenic bacteria is a global threat to human and veterinary medicine. Beyond antibiotics, antimicrobial peptides (AMPs) might be an alternative to inhibit the growth of bacteria, including AMR pathogens, on different surfaces. Biofilm formation, which starts out as bacterial adhesion, poses additional challenges for antibiotics targeting bacterial cells. The objective of this study was to establish a real-time method for the monitoring of the inhibition of (a) bacterial adhesion to a defined substrate and (b) biofilm formation by AMPs using an innovative thermal sensor. We provide evidence that the thermal sensor enables continuous monitoring of the effect of two potent AMPs, protamine and OH-CATH-30, on surface colonization of bovine mastitis-associated Escherichia (E.) coli and Staphylococcus (S.) aureus. The bacteria were grown under static conditions on the surface of the sensor membrane, on which temperature oscillations generated by a heater structure were detected by an amorphous germanium thermistor. Bacterial adhesion, which was confirmed by white light interferometry, caused a detectable amplitude change and phase shift. To our knowledge, the thermal measurement system has never been used to assess the effect of AMPs on bacterial adhesion in real time before. The system could be used to screen and evaluate bacterial adhesion inhibition of both known and novel AMPs.

scholarly journals Microbial Adhesion and Biofilm Formation on Microfiltration Membranes: A Detailed Characterization Using Model Organisms with Increasing Complexity

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
L. Vanysacker ◽  
C. Denis ◽  
P. Declerck ◽  
A. Piasecka ◽  
I. F. J. Vankelecom
Keyword(s):  
Membrane Fouling ◽  
Biofilm Formation ◽  
Bacterial Community Composition ◽  
Microbial Interactions ◽  
Model Systems ◽  
Model Organisms ◽  
Microbial Adhesion ◽  
Membrane Biofouling ◽  
Microfiltration Membranes ◽  
Cell Densities

Since many years, membrane biofouling has been described as the Achilles heel of membrane fouling. In the present study, an ecological assay was performed using model systems with increasing complexity: a monospecies assay usingPseudomonas aeruginosaorEscherichia coliseparately, a duospecies assay using both microorganisms, and a multispecies assay using activated sludge with or without spikedP. aeruginosa. The microbial adhesion and biofilm formation were evaluated in terms of bacterial cell densities, species richness, and bacterial community composition on polyvinyldifluoride, polyethylene, and polysulfone membranes. The data show that biofouling formation was strongly influenced by the kind of microorganism, the interactions between the organisms, and the changes in environmental conditions whereas the membrane effect was less important. The findings obtained in this study suggest that more knowledge in species composition and microbial interactions is needed in order to understand the complex biofouling process. This is the first report describing the microbial interactions with a membrane during the biofouling development.

scholarly journals The Influence of Residual Coagulant Al on the Biofilm EPS and Membrane Fouling Potential in Wastewater Reclamation

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1056
Author(s):  
Shu Sun ◽  
Zhenhao Zhao ◽  
Xiaochun Cui ◽  
Mingxin Huo ◽  
Zhi Geng
Keyword(s):  
Membrane Fouling ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Significant Rise ◽  
Membrane Technology ◽  
Major Contributor ◽  
Wastewater Reclamation ◽  
Control Groups ◽  
Membrane Treatment ◽  
Residual Al

Biofouling is inevitable in wastewater reclamation when using membrane technology. In particular, the extracellular polymeric substances (EPS) from biofilm is a major contributor to biofouling. Coagulation is critical in the process of reusing wastewater before membrane treatment, and residual coagulants (e.g., Al salts) are able to alter the characteristics of the biofilm EPS. However, the distribution of residual Al across varying biofilm EPS fractions and its effect on the membrane fouling potential resulting from biofilm EPS remains unclear. We found that 34% of the residual Al was present in the soluble EPS (S-EPS), 26% in the loosely bound EPS (LB-EPS) and 40% in the tightly bound EPS (TB-EPS). Moreover, compared with the control groups, the residual Al in biofilm induced more biofilm formation and more EPS formation. Al reduced the zeta potential and increased the hydrophobicity of the EPS. These changes induced a significant rise in the membrane fouling potential of S-EPS and LB-EPS. This work provides coagulation support for wastewater reclamation using membrane technology.

scholarly journals Mechanism of Membrane Fouling Control by HMBR: Effect of Microbial Community on EPS

2020 ◽  
Vol 17 (5) ◽  
pp. 1681
Author(s):  
Qiang Liu ◽  
Ying Yao ◽  
Delan Xu
Keyword(s):  
Microbial Community ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Extracellular Polymeric Substances ◽  
Microbial Community Composition ◽  
Domestic Wastewater ◽  
Control Group ◽  
Transmembrane Pressure ◽  
Fouling Control ◽  
Cake Layer

A hybrid membrane bioreactor (HMBR) employing activated sludge and biofilm simultaneously is proved to represent a good performance on membrane fouling control compared to conventional membrane bioreactor (CMBR) by reducing extracellular polymeric substances (EPS), especially bound EPS (B-EPS). In order to better understand the mechanism of membrane fouling control by the HMBR in regard of microbial community composition, a pilot scale HMBR operated to treat domestic wastewater for six months, and a CMBR operated at the same time as control group. Results showed that HMBR can effectively control membrane fouling. When transmembrane pressure reached 0.1 MPa, the membrane module in the HMBR operated for about 26.7% longer than that in the CMBR. In the HMBR, the quantity of EPS was significantly lower than that in the CMBR. In this paper, soluble EPS was also found to have a close relationship with cake layer resistance. The species richness and diversity in the HMBR were higher than those in the CMBR, and a certain difference between the compositions of microbial communities in the two reactors was confirmed. Therefore, the difference in microbial community compositions may be the direct reason why EPS in the HMBR was lower than that in the CMBR.

Effect of dead cells on biofouling in the reverse osmosis process

2013 ◽  
Vol 13 (5) ◽  
pp. 1396-1401
Author(s):  
Myung Seop Shin ◽  
Lan Hee Kim ◽  
Sung-Jo Kim ◽  
Chang-Min Kim ◽  
Kyu-Jung Chae ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Live Cells ◽  
Feed Water ◽  
Fouling Control ◽  
Flux Decline ◽  
Low Concentrations ◽  
Plate Counts ◽  
Heterotrophic Plate Counts

Biofilm formation in membrane processes causes a flux decline, pressure drop increase, and other adverse effects. Understanding the mechanisms of fouling, control, and cleaning are important in order to resolve fouling problems. In this paper, the effect of cell viability on biofouling was studied via a feed water analysis and membrane autopsy. Pseudomonas aeruginosa PAO1 was used as the model bacteria. Biofouling tests were divided into two parts: live cells and dead cells (autoclaved cells). The feed water was periodically collected every 3 h to analyze the total direct counts (TDCs), heterotrophic plate counts (HPCs), and extracellular polymeric substances (EPS). A membrane autopsy was performed to characterize the fouled membrane through TDCs and EPS. When dead cells were inoculated into the feed water, low concentrations of TDCs and EPS were measured in both the feed water and fouled membrane. As a result, it was determined that initial flux decline by biofouling can be reduced if feedwater is disinfected before the reverse osmosis process.

Process Description of an Unconventional Biofilm Formation by Bacterial Cells Autoagglutinating Through Sticky, Long, and Peritrichate Nanofibers

2019 ◽  
Author(s):  
Yoshihide Furuichi ◽  
Shogo Yoshimoto ◽  
Tomohiro Inaba ◽  
Nobuhiko Nomura ◽  
Katsutoshi Hori
Keyword(s):  
Formation Process ◽  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Waste Treatment ◽  
Large Cell ◽  
Dlvo Theory ◽  
Bacterial Cells ◽  
Chemical Production ◽  
Discontinuous Surface ◽  
Cell Cell

<p></p><p>Biofilms are used in environmental biotechnologies including waste treatment and environmentally friendly chemical production. Understanding the mechanisms of biofilm formation is essential to control microbial behavior and improve environmental biotechnologies. <i>Acinetobacter </i>sp. Tol 5 autoagglutinate through the interaction of the long, peritrichate nanofiber protein AtaA, a trimeric autotransporter adhesin. Using AtaA, without cell growth or the production of extracellular polymeric substances, Tol 5 cells quickly form an unconventional biofilm. In this study, we investigated the formation process of this unconventional biofilm, which started with cell–cell interactions, proceeded to cell clumping, and led to the formation of large cell aggregates. The cell–cell interaction was described by DLVO theory based on a new concept, which considers two independent interactions between two cell bodies and between two AtaA fiber tips forming a virtual discontinuous surface. If cell bodies cannot collide owing to an energy barrier at low ionic strengths but approach within the interactive distance of AtaA fibers, cells can agglutinate through their contact. Cell clumping proceeds following the cluster–cluster aggregation model, and an unconventional biofilm containing void spaces and a fractal nature develops. Understanding its formation process would extend the utilization of various types of biofilms, enhancing environmental biotechnologies.</p><p></p>

Antibiotics Application Strategies to Control Biofilm Formation in Pathogenic Bacteria

2020 ◽  
Vol 21 (4) ◽  
pp. 270-286 ◽  
Author(s):  
Fazlurrahman Khan ◽  
Dung T.N. Pham ◽  
Sandra F. Oloketuyi ◽  
Young-Mog Kim
Keyword(s):  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Extracellular Polymeric Substances ◽  
Quorum Quenching ◽  
Resistance Mechanisms ◽  
Bacterial Biofilm ◽  
Bacterial Cells ◽  
High Concentration ◽  
Biofilm Inhibition ◽  
Abiotic Surfaces

Background: The establishment of a biofilm by most pathogenic bacteria has been known as one of the resistance mechanisms against antibiotics. A biofilm is a structural component where the bacterial community adheres to the biotic or abiotic surfaces by the help of Extracellular Polymeric Substances (EPS) produced by bacterial cells. The biofilm matrix possesses the ability to resist several adverse environmental factors, including the effect of antibiotics. Therefore, the resistance of bacterial biofilm-forming cells could be increased up to 1000 times than the planktonic cells, hence requiring a significantly high concentration of antibiotics for treatment. Methods: Up to the present, several methodologies employing antibiotics as an anti-biofilm, antivirulence or quorum quenching agent have been developed for biofilm inhibition and eradication of a pre-formed mature biofilm. Results: Among the anti-biofilm strategies being tested, the sub-minimal inhibitory concentration of several antibiotics either alone or in combination has been shown to inhibit biofilm formation and down-regulate the production of virulence factors. The combinatorial strategies include (1) combination of multiple antibiotics, (2) combination of antibiotics with non-antibiotic agents and (3) loading of antibiotics onto a carrier. Conclusion: The present review paper describes the role of several antibiotics as biofilm inhibitors and also the alternative strategies adopted for applications in eradicating and inhibiting the formation of biofilm by pathogenic bacteria.

scholarly journals Myricetin as an Antivirulence Compound Interfering with a Morphological Transformation into Coccoid Forms and Potentiating Activity of Antibiotics against Helicobacter pylori

2021 ◽  
Vol 22 (5) ◽  
pp. 2695
Author(s):  
Paweł Krzyżek ◽  
Paweł Migdał ◽  
Emil Paluch ◽  
Magdalena Karwańska ◽  
Alina Wieliczko ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Biofilm Formation ◽  
Inhibitory Effect ◽  
Morphological Transformation ◽  
High Tendency ◽  
Minimal Inhibitory Concentrations ◽  
Coccoid Form ◽  
Stomach Diseases ◽  
Fold Reduction ◽  
H Pylori

Helicobacter pylori, a gastric pathogen associated with a broad range of stomach diseases, has a high tendency to become resistant to antibiotics. One of the most important factors related to therapeutic failures is its ability to change from a spiral to a coccoid form. Therefore, the main aim of our original article was to determine the influence of myricetin, a natural compound with an antivirulence action, on the morphological transformation of H. pylori and check the potential of myricetin to increase the activity of antibiotics against this pathogen. We observed that sub-minimal inhibitory concentrations (sub-MICs) of this compound have the ability to slow down the process of transformation into coccoid forms and reduce biofilm formation of this bacterium. Using checkerboard assays, we noticed that the exposure of H. pylori to sub-MICs of myricetin enabled a 4–16-fold reduction in MICs of all classically used antibiotics (amoxicillin, clarithromycin, tetracycline, metronidazole, and levofloxacin). Additionally, RT-qPCR studies of genes related to the H. pylori morphogenesis showed a decrease in their expression during exposure to myricetin. This inhibitory effect was more strongly seen for genes involved in the muropeptide monomers shortening (csd3, csd6, csd4, and amiA), suggesting their significant participation in the spiral-to-coccoid transition. To our knowledge, this is the first research showing the ability of any compound to synergistically interact with all five antibiotics against H. pylori and the first one showing the capacity of a natural substance to interfere with the morphological transition of H. pylori from spiral to coccoid forms.

scholarly journals Biofilm Formation in Xanthomonas arboricola pv. pruni: Structure and Development

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 546
Author(s):  
Pilar Sabuquillo ◽  
Jaime Cubero
Keyword(s):  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Environmental Changes ◽  
Nutrient Content ◽  
Infection Process ◽  
Bacterial Attachment ◽  
Key Factors ◽  
Cell Structures ◽  
Microscopy Techniques

Xanthomonasarboricola pv. pruni (Xap) causes bacterial spot of stone fruit and almond, an important plant disease with a high economic impact. Biofilm formation is one of the mechanisms that microbial communities use to adapt to environmental changes and to survive and colonize plants. Herein, biofilm formation by Xap was analyzed on abiotic and biotic surfaces using different microscopy techniques which allowed characterization of the different biofilm stages compared to the planktonic condition. All Xap strains assayed were able to form real biofilms creating organized structures comprised by viable cells. Xap in biofilms differentiated from free-living bacteria forming complex matrix-encased multicellular structures which become surrounded by a network of extracellular polymeric substances (EPS). Moreover, nutrient content of the environment and bacterial growth have been shown as key factors for biofilm formation and its development. Besides, this is the first work where different cell structures involved in bacterial attachment and aggregation have been identified during Xap biofilm progression. Our findings provide insights regarding different aspects of the biofilm formation of Xap which improve our understanding of the bacterial infection process occurred in Prunus spp and that may help in future disease control approaches.

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