Biofilms最新文献

{"title":"The effect of synthetic microbial spatial self-organization on the fate of antibiotic resistance genes","authors":"Yinyin Ma, David R. Johnson","doi":"10.5194/biofilms9-72","DOIUrl":"https://doi.org/10.5194/biofilms9-72","url":null,"abstract":"<p>Biofilms are considered as hotspots for the transfer of antibiotic resistance genes (ARGs), but very few studies have investigated the fate of ARGs (e.g. proliferation or elimination) in situ given different microbial spatial self-organization (SSO). SSO refers to a pervasive process during biofilm formation when microbes arrange themselves non-randomly across surfaces. So far the causes of SSO have been uncovered in a sense, however, the consequences of SSO were largely overlooked. Here, I hypothesize that the magnitude of inter-species intermixing, as one fundamental character of SSO, will determine the fate of ARG-carrying conjugative plasmid in both absence and presence of antibiotic selection. I evaluated this by performing range expansion experiments on agar plates to develop an artificial biofilm using a synthetic microbial community consisting of two isogenic Pseudomonas Stutzeri <em>A1501</em> who are facultative denitrifiers in anaerobic condition. By knocking out different functional genes responsible for different steps of denitrification I am able to modify the metabolic interactions between these two strains from competing (without trophic interaction) to cross-feeding (with trophic interaction), which will further result in different magnitude of inter-species intermixing. Competing group has lower magnitude due to demixing of two, while cross-feeding group has higher magnitude due to mixing. I observed that in the absence of antibiotic selection plasmid experienced faster pace of elimination in competing group than cross-feeding group, whereas in the presence of antibiotic selection plasmid proliferated more efficiently in cross-feeding group than competing group. These results suggest that SSO is a determining factor of the fate of ARGs in biofilms, which provides a novel perspective of better understanding ARGs-related pressing problems facing our society.</p>","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45800406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of essential oils on the biofilm formation and cell agglomeration of Burkholderia cepacia from industrial environment","authors":"Katrin Huth-Herms, A. Kintzel, A. Brehmer, C. Hein, Prof. Dr. h. c. Dr.-Ing. Eckart Uhlmann","doi":"10.5194/biofilms9-50","DOIUrl":"https://doi.org/10.5194/biofilms9-50","url":null,"abstract":"Burkholderia cepacia (B. cepacia) is one of nine species the Burkholderia cepacia complex, a group of gram-negative, motile, non-spore-forming and rod-shaped bacteria. Contamination by B. cepacia is found in different industrial issues. B. cepacia affect manufacturing process chains by contaminating the working fluids with planktonic cells and biofilms. Because of the opportunistic pathogenicity to plants, animals, humans and and the multi-drug resistance, B. cepacia is difficult to treat. An alternative treatment method could be the use of herbal raw materials, such as essential oils and their active ingredients. This study aims: (i) to identify the antimicrobial potential of essential oils on the growth of four B. cepacia isolates, (ii) to analyse the influence of active ingredients, on planktonic growth and biofilm formation, (iii) to better understand the impact of commercial and naturally biocides to cell agglomeration as a precursor to mature biofilms. Starting with agar dilution method to evaluate the antimicrobial potential of twenty-three essential oils against B. cepacia (Burk_09, Burk_23, Burk_52 and Burk_309) isolated from cathodic dip coating systems and the wild type (DSM_7288), it was all ready possible to identify eight essential oils that inhibit the growth of B. cepacia. Serial microdilution was used to determine the minimal inhibitory concentration (MIC) of the essential oils for growth and biofilm formation inhibition of B. cepacia. The MIC of Melaleuca alternifolia and Citrus aurantium dulcis essential oils were tested equally for all strains. Essential oils contain active ingredients against the growth of multi-drug resistant and pathogenic bacteria. From twelve active substances among others, Terpinen-4-ol and Geraniol were identified that inhibited growth and biofilm formation. It is concluded that essential oils and active ingredients have a good antimicrobial potential, demonstrating a possible more environmentalfriendly alternative to commercial biocides applying in industrial fluids.","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46041534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antibiofilm and antivirulence effect of stilbenes on clinically relevant staphylococci","authors":"P. Kašparová, O. Maťátková","doi":"10.5194/biofilms9-32","DOIUrl":"https://doi.org/10.5194/biofilms9-32","url":null,"abstract":"<p>Genus <em>Staphylococcus</em> comprises many greatly pathogenic species like <em>S.&#160;aureus</em>, <em>S.&#160;epidermidis</em> or <em>S. saprophyticus</em>. The great pathogenicity of stated species is often facilitated by their capability to form thick complex biofilms on various biotic or abiotic surfaces. Biofilm formation together with extracellular hydrolases or toxins represents important virulence factor, which increases persistence of staphylococci in host via enhancing their ability to evade host immune system and further promote the infection development. With an increased emergence of antibiotic resistance among pathogenic bacteria including staphylococci the search for novel antibiotic compounds with antivirulence effect is sought. Such substances might be stilbenes, phenolic compounds isolated from various plants (<em>Vitis</em>&#160;spp., <em>Vaccinium</em> spp., <em>Pterocarpus</em> spp., <em>Pinus</em> spp.). They possess strong antioxidant activity and a wide spectrum of beneficial pharmacological effects (antitumor, hypolipidemic, hypoglycemic). Apart from that, they also have great antimicrobial activity with a potent ability to enhance antibiotics action in combination.</p>\u0000<p>Presented work focused on resveratrol, pterostilbene (PTE) and pinosylvine and their effect on <em>S. aureus</em> and <em>S. epidermidis</em> biofilm formation. The effect of stilbene representatives on production of other virulence factors (proteases, phospholipases, haemolysins), cell surface hydrophobicity and morphology was also observed.</p>\u0000<p>PTE was found to be the most effective among studied stilbenes against <em>S. aureus</em> and <em>S. epidermidis</em> biofilm with minimum biofilm inhibitory concentrations (MBIC₈₀) ranging from 40 to 130 mg/l. Its effect on mature staphylococcal biofilm eradication was even greater with 80% eradication rate achieved by 40-75 mg/l. PTE (49 mg/l) was found to have a potent combinatory antibiofilm activity with erythromycin or tetracycline (5 mg/l both) causing more than 80% inhibition in metabolic activity of biofilm cells. It was able to permeabilize cytoplasmic membrane, thus probably enabling antibiotic uptake by the cell. PTE also altered cell surface hydrophobicity and production of haemolysin.</p>\u0000<p>PTE might be the solution to increasing biofilm-related resistance problem and a promising candidate with antibiofilm and antivirulence potential for future antibiotic treatment of staphylococcal infections.</p>\u0000<p>&#160;</p>\u0000<p><em>This work was supported by the grant of Specific university research &#8211; grant No. A2_FPBT_2020_004.</em></p>","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46071176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new surface wiping test to study surface disinfection by a novel chemical combination","authors":"J. Malheiro, F. Borges, J. Maillard, M. Simões","doi":"10.5194/biofilms9-155","DOIUrl":"https://doi.org/10.5194/biofilms9-155","url":null,"abstract":"<p>Effective biofilm disinfection is difficult to be implemented in healthcare settings and industry. In particular, surface disinfection is crucial to prevent microbial contaminations. However, disinfectants misuse has led to an increased concern on the existence of resistance and cross-resistance phenomena due to inadequate disinfection practices. The purpose of this study was the development of a formulation to be used for surface disinfection with wipes. The idea was to produce a formulation based on the combination between the quaternary ammonium compound - cetyltrimethylammonium bromide (CTAB) and a natural product - cinnamaldehyde. In addition, a new disc methodology to assess wiping efficiency was developed based on the Wiperator test (E2967-15) and on the quantitative test method for the evaluation of bactericidal and yeasticidal activity on non-porous surfaces with mechanical action employing wipes in the medical area, 4- field test (EN 16615:2015). The combination of CTAB and cinnamaldehyde was synergic in terms of antimicrobial action against Escherichia coli and Staphylococcus aureus. After stablishing the final formulation, wiping efficacy was assessed with the new methodology. In this case, a contaminated surface (6.20 &#177; 0.21 log₁₀ CFU of E. coli and 7.10 &#177; 0.06 log₁₀ CFU of S. aureus) was wiped using two different wipes in terms of composition, thickness and porosity (A and B). After wiping the contaminated surface with wipe A, without the formulation, 3.42 &#177; 0.46 log₁₀ CFU (E. coli) and 5.38 &#177; 0.20 log₁₀ CFU (S. aureus) remained on the surface while in the presence of the formulation the bacteria present were under the limit of detection for E. coli and 2.76 &#177; 0.22 log₁₀ CFU for S. aureus. The formulation was also able to prevent the transfer of bacteria to clean surfaces after wiping the contaminated surface. In the case of wipe A, after wiping the contaminated surface and the subsequent 2 clean surfaces, a total reduction of 4.35 &#177; 0.22 log₁₀ CFU and 4.27 &#177; 0.22 log₁₀ CFU was achieved when the wipe was impregnated with the formulation in comparison with 2.45 &#177; 0.41 log₁₀ CFU and 1.50 &#177; 0.35 log₁₀ CFU of removal just by mechanical action for E. coli and S. aureus, respectively. For wipe B a general lower reduction was observed but the same behaviour was detected with the use of the formulation when comparison to just mechanical action. This work highlights the enormous potential of combinatorial approach to increase the efficacy of already used biocides diminishing their in-use concentration and consequently their environmental and public health burden.</p>\u0000<p>&#160;</p>\u0000<p><strong>Acknowledgements</strong></p>\u0000<p>This work was financed by: UIDB/00511/2020 of the Laboratory for Process Engineering, Environment, Biotechnology and Energy &#8211; LEPABE - funded by national funds through th","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48487373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of PolyHydroxyAlkanoate Bioelectrosynthesis by the thermophilic bacterium Kyrpidia spormannii","authors":"G. Pillot, Soniya Sunny, V. Comes, S. Kerzenmacher","doi":"10.5194/biofilms9-54","DOIUrl":"https://doi.org/10.5194/biofilms9-54","url":null,"abstract":"<p>The electrosynthesis of valuable compounds by biofilms on electrodes is intensively studied since few years. However, the actual biofilms growing so far on cathode produce mainly small inexpensive compounds such as acetate or ethanol. A novel Knallgas bacteria, <em>Kyrpidia spormannii</em> have been recently described to grow on cathode in thermophilic and microaerophilic conditions, producing significant amount of PolyHydroxyAlkanoates (PHAs) (Reiner et al., 2018). These PHA are promising sustainable bioplastic polymers with the potential to replace petroleum-derived plastics in a variety of applications. However, the effect of culture conditions and electrode properties on the growth of <em>K. spormannii</em> biofilm and PHA production is still unclear.</p>\u0000<p>We present in this study the successful development and operation of autotrophic biocathode whereby the electroactive biofilm was able to grow by utilizing CO₂ and a cathode as the sole carbon and electron source, respectively. We report for the first time, the effect of operating conditions of the Bioelectrochemical system (BES), cathode materials and cathode surface modification on current consumption, biofilm formation, PHA productivity and overall coulombic efficiency of a <em>K. spormannii</em> culture growing on electrodes. In particular, the focus of this study lies on optimization of three main operating conditions, which are the applied cathode potential, pH buffer and the oxygen concentration in the feed gas. Increased biofilm formation and PHA production was observed at an applied potential of -844mV vs. SCE, pH 6.5, O₂ saturation of 2.5%, and for a graphite cathode modified by CO₂ activation. The PHA concentration in the biofilm reached a maximum of &#8776;40 &#956;g&#183;cm^-2 after optimization. The resultant PHA yield reported after optimization is increased by 12.2 times in comparison to previous results. In conclusion, these findings take microbial electrosynthesis of PHA a step forward towards practical implementation.</p>","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71171463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced erosion resistance of biopolymer-enriched B. subtilis NCIB 3610 biofilms","authors":"Elif N. Hayta, O. Lieleg","doi":"10.5194/biofilms9-56","DOIUrl":"https://doi.org/10.5194/biofilms9-56","url":null,"abstract":"<p>Erosion resistance is one of the advantages bacteria gain by producing biofilms. While it is undesirable for us humans when biofilms grow on medical devices or industrial pipelines, biofilms with a high erosion resistance can be advantageous for biotechnological applications. Here, we demonstrate how the erosion resistance of <em>B. subtilis</em> NCIB 3610 biofilms can be enhanced by integrating foreign (bio)polymers such as &#947;-polyglutamate (PGA), alginate and polyethylene glycol (PEG) into the matrix during biofilm growth.<br /><br />Artificial enrichment of the NCIB 3610 biofilms with these biopolymers causes a significant increase in the erosion resistance by slightly changing the surface topography: A decreased cavity depth on the surface results in an alteration in the mode of surface superhydrophobicity, and we obtain a state that is located somewhere between rose-petal like and lotus-like wetting resistance. Surprisingly, the viscoelastic and microscopic penetration properties of the biofilms are not affected by the artificial incorporation of (bio)polymers. As we obtained similar results with all the biopolymers tested (which differ in terms of charge and molecular weight), this indicates that a variety of different (bio)polymers can be employed for a similar purpose.<br /><br />The method introduced here may present a promising strategy for engineering beneficial biofilms such, that they become more stable towards shear forces caused by flowing water but, at the same time, remain permeable to nutrients or other molecules.</p>","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42527241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"BiofilmQ, a software tool for quantiative image analysis of microbial biofilm communities","authors":"H. Jeckel, Raimo Hartmann, Eric Jelli, K. Drescher","doi":"10.5194/biofilms9-26","DOIUrl":"https://doi.org/10.5194/biofilms9-26","url":null,"abstract":"Biofilms are now considered to be the most abundant form of microbial life on Earth, playing critical roles in biogeochemical cycles, agriculture, and health care. Phenotypic and genotypic variations in biofilms generally occur in three-dimensional space and time, and biofilms are therefore often investigated using microscopy. However, the quantitative analysis of microscopy images presents a key obstacle in phenotyping biofilm communities and single-cell heterogeneity inside biofilms. Here, we present BiofilmQ, a comprehensive image cytometry software tool for the automated highthroughput quantification and visualization of 3D and 2D community properties in space and time. Using BiofilmQ does not require prior knowledge of programming or image processing and provides a user-friendly graphical user interface, resulting in editable publication-quality figures. BiofilmQ is designed for handling fluorescence images of any spatially structured microbial community and growth geometry, including microscopic, mesoscopic, macroscopic colonies and aggregates, as well as bacterial biofilms in the context of eukaryotic hosts.","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41509597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Understanding how operating conditions affect biofouling structure in spacer filled membrane filtration channels using optical coherence tomography","authors":"K. Huisman, B. Blankert, Szilárd S. Bucs, J. Vrouwenvelder","doi":"10.5194/biofilms9-77","DOIUrl":"https://doi.org/10.5194/biofilms9-77","url":null,"abstract":"The growth of biofilms, causing biofouling on the membrane and feed spacer surface, is an unavoidable phenomenon in reverse osmosis. Biofouling can lead to unacceptable losses in product quality and quantity, and membrane lifetime. Process conditions such as crossflow velocity and nutrient concentration in the feed water strongly affect the development of biofilms. To improve system performance, understanding the relation between process conditions, biofilm development, and system performance is key. Optical coherence tomography (OCT), is increasingly applied to characterize biofilm structure in-situ and non-destructively. In OCT, near-infrared light is used to capture 2D and 3D images from within optical scattering media. In spacer filled channels with representative biodegradable nutrient conditions in the feed, biofilms often develop heterogeneously and dispersed. In such systems, commonly used structural parameters such as average thickness, average roughness, and average porosity may not be reflected in the system performance. In this study, biofilm structural and spatial parameters are explored with the objective to link biofouling in spacer filled channels to system performance indicators. For this purpose, biofilms are grown in membrane fouling simulators at different nutrient concentrations and flow rates. Biofilm development on the feed spacer and on the membrane and system performance (pressure drop, transmembrane pressure, rejection) are monitored. Understanding the impact of (i) feed water quality and flow rate on biofilm growth and of (ii) biofilm structure and spatial distribution on system performance will lead to the development of more effective strategies for biofouling control.","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49347084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biofilm formation capacity of S. aureus under diabetic environments","authors":"María Fernández Grajera, María Coronada Fernández Calderón, Miguel Ángel Pacha Olivenza, C. P. Giraldo, A. Moreno, María Luisa González Martín","doi":"10.5194/biofilms9-141","DOIUrl":"https://doi.org/10.5194/biofilms9-141","url":null,"abstract":"María Fernández Grajera, María Coronada Fernández Calderón, Miguel A. Pacha Olivenza, Ciro Pérez Giraldo, Amparo M. Gallardo Moreno, and María Luisa González Martín University of Extremadura, Department of Applied Physics, Badajoz, Spain Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Badajoz, Spain University Institute of Extremadura Sanity Research (iNube), Badajoz, Spain University of Extremadura, Department of Biomedical Science, Badajoz, Spain","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49364012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Viability of mono-specie biofilm formed by the solvent producer Clostridium beijerinckii during continuous fermentation in packed bed bioreactor.","authors":"M. Carrie, H. Velly, Jean-Christophe Gabelle, Fadhel Ben-Chaabane","doi":"10.5194/biofilms9-47","DOIUrl":"https://doi.org/10.5194/biofilms9-47","url":null,"abstract":"<p>Butanol and Isopropanol are naturally produced by the bacteria C. beijerinckii. Those products are used in large field of applications such as fuel and bulk chemicals. Since butanol is toxic at small concentration for cells, bacterial growth and metabolism are inhibited during classical batch fermentation (1). These phenomena lead to the production of low solvent concentration (around 7 g.L^-1) and a low volumetric productivity (0,13 g.L^-1.h^-1) (2). Continuous fermentation can be performed in order to avoid product inhibition by&#160; a continuous removal of fermentation broth. However, the solvent productive biomass is easily washout at high dilution rate because of the low maximum growth rate of the strain in this metabolism phase&#160; (0,05 h^-1) (3). To overcome this issue, cell immobilization of&#160; C. beijerinckii by biofilm formation on solid support is the best solution. As a result, the biomass residence time can be uncorrelated from the hydraulic residence time leading to a higher viable biomass concentration in the bioreactor and consequently a higher volumetric productivity (up to 5 g.L^-1.h-1 ) (4). Our study aimed&#160; at evaluating biofilm viability which is an important parameter that is linked to process productivity and has been little studied in the case of the IBE fermentation (5).</p>\u0000<p>In this study we developed two techniques to monitor biofilm viability during immobilized cell fermentation: Flow cytometry (FC) and PMA qPCR. After FC analysis, a high background noise due to the biofilm extra polymeric substance is obtained. Consequently, an enzymatic&#160; sequential enzymatic biofilm deconstruction using Dnase I and Proteinase K was developed . This pre-treatment successfully lowered the background noise of this analysis. The suspensions obtained were stained with carboxyfluoresceine diacetate (cFDA) and propidium iodide (PI) which are indicators of cellular activity and alteration of membrane integrity, respectively,&#160; and analyzed by flow cytometry. The percentage of viable cells obtained after pre-treatment compared to the control sample is increased from 2.6 &#177; 0.9 % to 22.8 &#177; 8.6% because of the background noise decrease. PMA-qPCR confirmed the results obtained by flow cytometry without using enzymatic pre-treatment. Although FC is less accurate than PMA-qPCR, this technique is less time-consuming, cheaper and reliable to study biofilm viability.</p>\u0000<p><strong>References</strong></p>\u0000<ol>\u0000<li>Jones et al (1986) Acetone-Butanol Fermentation Revisited, Microbiological Reviews 50, 484&#8211;524.</li>\u0000<li>Ferreira dos Santos Vieira, C., Maugeri Filho, F., Maciel Filho, R., and Pinto Mariano, A. (2019) Isopropanol-butanol-ethanol (IBE) production in repeated-batch cultivation of Clostridium beijerinckii DSM 6423 immobilized on sugarcane bagasse, Fuel, 116708.</li>\u0000<li>Ahmed, I., Ross, R. A., Mathur, V. K., and Chesbro, W. R. (1988) Growth rate depend","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45608586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}