Biofilms最新文献

{"title":"Interaction of flow field and biofilm formation in a dripper supplied by reclaimed wastewater","authors":"Nassim Ait Mouheb, J. Qian, M. Wagner, H. Horn","doi":"10.5194/biofilms9-88","DOIUrl":"https://doi.org/10.5194/biofilms9-88","url":null,"abstract":"In order to improve the knowledge of these mechanisms, the objective was to combine the numerical flow simulations to three-dimensional measurements of biofilm along a milli-fluidic system (nominal flow rate 1L/h) fed by treated wastewater. At first, using the Optical Coherence Tomography (OCT) method and based to Qian et al, 2018 studies, the bio-clogging structure was measured at different levels of fouling (up to 77% of channel volume). Secondly, the new fouled dripper geometries were integrated to 3D CFD models (using comsol multiphysics software) to analyse the effect of biofilm on flow topology and the dripper hydraulic parameters (pressure drop, shear stress, turbulence kinetic energy in particular).","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":"42212004","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":"Talk2clean: application of probiotics to control biofilm in industrial water circuits – a innovative application","authors":"H. Kleinjan, C. Meunier, S. Nonet, Mickael Michel","doi":"10.5194/biofilms9-95","DOIUrl":"https://doi.org/10.5194/biofilms9-95","url":null,"abstract":"Biofilms are omnipresent in industrial cooling water circuits and frequently lead to technical and economic problems. Yet, methods to remove biofilms may be inefficient, due to the EPS layer, which provides a protective layer against penetration of disinfectants. In combination with stricter legislation and increased environmental awareness, this has opened the search for alternative strategies to control biofilms in cooling water systems.","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":"47647371","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":"Genomic screening for novel peptide antibiotics in biofilm cyanobacteria by in-silico analysis and PCR","authors":"S. Lenz, J. Walther, D. Strieth, R. Ulber","doi":"10.5194/biofilms9-24","DOIUrl":"https://doi.org/10.5194/biofilms9-24","url":null,"abstract":"<p>Cyanobacteria are a group of phototrophic prokaryotes commonly known as blue-green algae. They grow embedded as biofilms in a thick matrix of extracellular polymeric substances (EPS) and can produce a highly diverse range of secondary metabolites, which are interesting in terms of their antimicrobial activity. Among these components, polyketide and polypeptide molecules are dominating. Antimicrobial polypeptide molecules are usually post-translational-modified or synthesised by non-ribosomal peptide synthetase (NRPS). Standard screening for antibiotics by inhibition tests is very time consuming and expression of antimicrobic activity highly depend on cultivation conditions. Therefore, they can vary between different cultivations. On a genomic level existing, but in this cultivation not synthesized, antibiotics are completely neglected. Due to the increasing amount of available genomic sequence data, screening for novel antibiotics can also be done in-silico. Highly homologous sequences to known antibiotic gen clusters can be determined in cyanobacterial genomes and eventually be detected in-vivo through PCR analysis. Compared to inhibition tests, a major advantage of PCR is the little amount of biomass needed. As the growth of cyanobacteria is slow, e.g. Trichocoleus sociatus (0.44&#160;d^-1) compared to bacteria like Escherichia coli (2.08&#160;h^-1), this leads to significant shorter cultivation and screening time. In addition, qPCR can be used to determine gene expression quantity of the considered genes. PCR with degenerated primers for specific gen cluster like NRPS, polyketide synthetases, lanthipeptides etc. can also be used to screen non-sequenced cyanobacteria for the possible origin of an unidentified antibiotic.</p>\u0000<p>The following work is part of the iProcess project, whose overall scientific goal is to develop the process engineering fundamentals for using fungi and cyanobacteria as production organisms for pharmaceutically active substances. As part of the iProcess project, a semi-continuous process for the production of antibiotics from cyanobacteria biofilms in aerosol reactors shall be developed. Aim of the following work is the in-silico search for new polypeptide antibiotics, as well as the subsequent in-vivo detection to discover promising cyanobacteria as production strains. In the first instance, the screening is focusing on the intern cyanobacteria strain collection of the TU Kaiserslautern. Subsequently the new strains will be cultivated as biofilms in an aerosol reactor and the resulting extracellular polymeric substances can be analysed for their antimicrobial activity.</p>\u0000<p>&#160;</p>\u0000<p>This project is financially supported by Ministry of Science, Further Education and Culture of Rhineland-Palatinate (mwwk.rlp) (iProcess intelligent process development &#8211; from modelling to product).</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":"49223591","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":"First steps for the scale up of a dual trophies microtubular biofilm reactor - preventing biofilm detachment","authors":"A. Kenkel, Andreas Schmid, R. Karande, Katja Bühler","doi":"10.5194/biofilms9-13","DOIUrl":"https://doi.org/10.5194/biofilms9-13","url":null,"abstract":"<p>The use of phototrophic cyanobacteria in biotechnology is highly interesting as they represent a carbon neutral production platform, relying mainly on carbon dioxide, light and water for growth. However, one key bottleneck for utilizing cyanobacteria as production hosts is that in the currently established cultivation systems like tube or flatpanel reactors only cell densities of 2 to 4 g_CDW/L are possible, which is at least 20 times too low for most applications. One promising concept to solve this shortcoming is the cultivation of such microbes as dual trophies biofilms in microtubular systems in a segmented flow fashion with air bubbles, as recently reported in [1]. According to the aspects mentioned in Posten et. al [2], it becomes clear that the concept fulfils most requirements for photo-bioreactors. Firstly, the surface area to volume ratio is increasing with decreasing tube diameter. Hence, the path of the light through the reactor is reduced, leading to an optimal light supply. Secondly, using air segments increases the mixing within the reactor leading to a better supply of the cells with a carbon source as well as a better extraction of oxygen. Apart from that, the attached biofilm provides continuous cell regeneration and thus a continuous production system. All these aspects lead to a biomass concentration in this reactor system of up to 60 g_CDW/L [1].</p>\u0000<p>The microtubular system was successfully applied in the challenging conversion of cyclohexane to cyclohexanol [1]. The reaction was conducted in a small lab scale system utilizing capillaries of 20 cm length, with a total volume of 1.4 mL. Here, we are evaluating the impact of larger scale on biofilm performance. Experiments were conducted in 1 m capillaries with 3 mm inner diameter. First, the impact of different flow rates was investigated. Results show, that a total minimal flow rate of 104 &#181;L/min (52 &#181;L air and 52 &#181;L medium /min) leads to a significant biofilm detachment in various positions in the tube after one week of cultivation. A total flow rate of 520 &#181;L/min (260 &#181;L air and 260 &#181;L medium /min) prevents detachment, however, it seems to hinder full surface coverage of the tube. An optimal condition turned out to be a cultivation of the biofilm with a starting flowrate of 520 &#181;L/min for the initial attachment of the cells and a consecutive decrease of the flow to 104 &#181;L/min after one week of cultivation. Thereby biofilm detachment was prevented and full surface coverage was achieved, while scaling the system by 5 fold. Respective data will be presented and discussed.</p>\u0000<p>[1] Hoschek, Heuschkel, Mixed-species biofilms for high-cell-density application of <em>Synechocystis</em> sp. PCC 6803 in capillary reactors for continuous cyclohexane oxidation to cyclohexanol, Bioresource Technology, 2019</p>\u0000<p>[2] Posten, Design principles of photo-bioreactors for cultivation of microalgae, Engineering in Life Scien","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":"45358873","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 in the life cycle of the cellulolytic actinomycete Thermobifida fusca","authors":"A. Alonso, P. Pomposiello, S. Leschine","doi":"10.1017/S1479050508002238","DOIUrl":"https://doi.org/10.1017/S1479050508002238","url":null,"abstract":"Actinomycetes have been used with enormous success in industrial processes; however, little is known about biofilm formation by these filamentous microbes, or community development on insoluble substrates such as cellulose. We hypothesized that biofilm formation is a general strategy used by actinomycetes in the degradation of cellulose, and that it may serve as a means for these microbes to secure nutrients and persist in their environments. The objective of this study was to examine biofilm production by Thermobifida fusca , an actinomycete that rapidly degrades cellulose by means of a well-characterized extracellular cellulase system. Thermobifida fusca cells grew as biofilms attached to both nutritive (e.g. dialysis tubing membrane) and non-nutritive surfaces. Dialysis tubing was colonized by T. fusca aleuriospores but not by mycelial pellets, except when mycelial pellets were disrupted by sonication. Microscopic examination of surface-attached growth revealed structures characteristic of biofilms, with cells embedded in fibrous material suggestive of an extracellular polymeric matrix. Concanavalin A bound to the extracellular polymeric substance of biofilms and mycelial pellets, indicating alpha-linked d -mannosyl and/or alpha-linked d -glucosyl residues. The carbohydrate content of both biofilms and mycelial pellets increased during growth. Also, DNase I inhibited biofilm production, suggesting a role for extracellular DNA in T. fusca biofilm development. Cellulose degradation and expression of celE (encoding endoglucanase E5) was similar for T. fusca biofilms and mycelial pellets. Results of this study indicate that, in the life cycle of this actinomycete, cellulose is specifically colonized by aleuriospores, which germinate, grow and degrade cellulose, ultimately developing into biofilms encased in a carbohydrate-containing exopolymeric matrix, a hallmark of biofilm production.","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":"1 1","pages":"1-11"},"PeriodicalIF":0.0,"publicationDate":"2008-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1479050508002238","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57038253","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":"Studies on enhancement of biofilm formation and adherence due to mechanical treatment of titanium surfaces in cooling-water systems","authors":"R. P. George, J. Gopal, P. Muraleedharan, B. Anandkumar, R. Baskaran, S. Maruthamuthu, R. Dayal","doi":"10.1017/S1479050508002226","DOIUrl":"https://doi.org/10.1017/S1479050508002226","url":null,"abstract":"Titanium has proven to be the heat exchanger material of choice for seawater- \u0000cooled power plants owing to its outstanding resistance to pitting and \u0000crevice corrosion in a wide range of aggressive media. However, the inertness \u0000of the titanium surface makes it highly susceptible to biofilm formation and \u0000subsequent biofouling. This can hinder the heat transfer properties and flow \u0000of water. Fouling control strategies in condensers include a combination \u0000of mechanical, chemical and thermal treatments. However, reports from \u0000various industrial situations suggest that mechanical treatment may not \u0000have long-term effects. This study aimed to find out whether mechanical \u0000cleaning eventually enhances biofilm formation and increases the adherence \u0000of biofilm. In our studies epifluorescence micrographs of biofilms on control \u0000and mechanically treated titanium surfaces clearly showed accelerated biofilm \u0000formation as well as increased adherence on themechanically cleaned surface. \u0000Total counts of viable bacteria acquired by culturing technique, and biofilm \u0000thickness measurements made using microscopic techniques, confirmed this \u0000observation. Surface profilometry showed increased roughness of the titanium \u0000surface, facilitating adherence of biofilm. The number of microbial species \u0000was higher on mechanically cleaned and re-exposed surfaces than on fresh \u0000titanium. Thus we concluded that mechanical cleaning can increase biofilm \u0000formation and adherence of biofilm, thereby increasing the potential of \u0000biofouling in the long term.","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":"1 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2008-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1479050508002226","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57038244","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":"EDTA treatment diminishes the antibacterial and anti-adherence effect of calcium hydroxide on Enterococcus faecalis : an in vitro study","authors":"S. George, A. Kishen","doi":"10.1017/S147905050800224X","DOIUrl":"https://doi.org/10.1017/S147905050800224X","url":null,"abstract":"This study sought to understand the cell surface characteristics, viability and biofilm-forming potential of Enterococcus faecalis cells sequentially exposed to EDTA and calcium hydroxide, as in endodontic treatment. Bacterial cells exposed to EDTA and calcium hydroxide were assayed for cell viability, membrane integrity, cell surface hydrophobicity and surface charge, while alteration in the surface topography of E. faecalis cells was examined using atomic force microscopy (AFM). The bacterial adherence potential to type I collagen was also examined to assess the biofilm-forming capacity of E. faecalis cells exposed to EDTA and calcium hydroxide. It was found that calcium hydroxide treatment reduced the viability of E. faecalis . However, prior exposure to EDTA significantly reduced the antibacterial effect of calcium hydroxide ( P P E. faecalis to type I collagen. These effects due to calcium hydroxide were also significantly altered in EDTA-pretreated cells ( P E. faecalis cells to EDTA.","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":"7 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2008-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S147905050800224X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57038264","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":"Effect of gravitational deposition on biofilm formation and development","authors":"Y. Yang","doi":"10.1017/S1479050508002251","DOIUrl":"https://doi.org/10.1017/S1479050508002251","url":null,"abstract":"","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":"1 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2008-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1479050508002251","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57038277","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":"Susceptibility of microcosm subgingival dental plaques to lethal photosensitization","authors":"I. Allan, J. O'Neill, C. Hope","doi":"10.1017/S1479050507002219","DOIUrl":"https://doi.org/10.1017/S1479050507002219","url":null,"abstract":"Photodynamic therapy (PDT) offers potential as a non-invasive treatment of periodontal disease. In this study, microcosm biofilmswere grown in vitro under conditions designed to mimic subgingival plaques typically found in patients with periodontitis. To investigate potential PDT modalities, biofilms were exposed to light from a helium/neon laser in conjunction with a photosensitizer, toluidine blue O (TBO), at varying output and concentration, respectively. \u0000To determine cytotoxic effects, viability profiling was undertaken on whole biofilms using standard plating methods, and on horizontal cross-sections of biofilms using confocal laser-scanning microscopy (CLSM) in conjunction \u0000with a differential viability stain. A light energy dose of 94.5 J in combination with 81.7 µM TBO was found to be optimal, achieving significant kills of over 97%. CLSM enabled visualization of the effects of PDT in three dimensions. \u0000Viability profiling of the CLSM images revealed that lethal photosensitization was most effective in the upper layers of biofilm. PDT was found to reduce the viability of subgingivally modelled plaques in vitro by a magnitude similar to \u0000that of chlorhexidine digluconate, which is commonly used to treat periodontal disease. The findings of this study indicate that PDT may be an effective alternative to conventional modalities in the treatment of periodontal disease.","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":"1 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2007-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1479050507002219","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57038231","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":"Molecular identification of species comprising an unusual biofilm from a groundwater treatment plant","authors":"M. Gillings, M. Holley, M. Selleck","doi":"10.1017/S1479050507002098","DOIUrl":"https://doi.org/10.1017/S1479050507002098","url":null,"abstract":"Orica's groundwater treatment plant in Botany, NSW, Australia, was designed to remove and destroy volatile organic compounds from polluted groundwater and to treat the water for reuse on the Botany Industrial Park. The initial steps in this process involved acidification of the groundwater and air stripping. During this operation, very large quantities of a biofilm formed within the air stripper, necessitating weekly clean-outs. We investigated the composition of this biofilm using molecular methods. Total DNA extracted from biofilm material was used as a template for amplification of both bacterial 16 S ribosomal DNA (rDNA) and the eukaryotic rDNA internal transcribed spacer region. Cloning and sequencing of these products showed that the biofilm was composed primarily of a bacterium belonging to the genus Acidocella , a filamentous fungus ( Trichoderma asperellum ), and the ascomycetous yeasts Pichia , Candida and Geotrichum . This unusual biofilm was composed of acidophiles that were capable of rapidly generating large amounts of biomass under these conditions. When acidification of the groundwater ceased, the biofilm no longer formed.","PeriodicalId":87392,"journal":{"name":"Biofilms","volume":"3 1","pages":"19-24"},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S1479050507002098","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57038167","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}