Biological Sciences
Biofilms
Biofilms are complex communities of microorganisms that adhere to surfaces and are encased in a self-produced matrix of extracellular polymeric substances. They play a significant role in various natural and industrial processes, including wastewater treatment, corrosion, and medical infections. Biofilms are known for their resilience and ability to resist antimicrobial treatments, making them a subject of interest in research and industry.
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11 Key excerpts on "Biofilms"
eBook - PDFMicrobial Biofilms
Importance and Applications
- Dharumadurai Dhanasekaran, Nooruddin Thajuddin, Dharumadurai Dhanasekaran, Nooruddin Thajuddin(Authors)
- 2016(Publication Date)
- IntechOpen(Publisher)
We believe that by recognising Biofilms within a continuum of aggregations or communities with varying properties, it will enable a more extensive investigation of bacterial colonisation, and in particular, allow us to distinguish those processes governing general colonisation and ecological success from those unique to particular environments and specialised strategies. Costerton et al. [2] defined Biofilms as ‘matrix-enclosed bacterial populations adherent to each other and/or to surfaces or interfaces ... (and) includes microbial aggregates and floccules and also adherent populations within the pore spaces of porous media’. Although this definition is broad (i.e. sensu lato), there is a presumption by current researchers that Biofilms are those structures formed on submerged solid surfaces (i.e. at the L-S interface) and that other structures associated with surfaces or interfaces are somehow different or inconsequential. We would suggest that L-S interface Biofilms as observed in flow-cells and microtitre plates are a means to investigate biofilm formation independently of natural environments or context, as it is difficult or impossible to extrapolate from these simple in vitro systems to the more complex natural environments from which the bacteria of interest were first isolated [29–31]. We note that in some later reviews, the description of Biofilms is extended with more examples. However, this has also lead to a more relaxed (sensu amplo) definition in which ‘biofilm’ is frequently used as a synonym of ‘aggregation’, even though the former is often defined by the latter (e.g. [42]). As a matter of etymology, ‘aggregation’ which originates in late Middle English (1150–1500 AD) should take precedence over ‘biofilm’ whose usage largely stems from the 1990s. Viewing Biofilms within the Larger Context of Bacterial Aggregations http://dx.doi.org/10.5772/62912 5
eBook - ePubNew and Future Developments in Microbial Biotechnology and Bioengineering: Microbial Biofilms
Current Research and Future Trends in Microbial Biofilms
- Mukesh Kumar Yadav, Bhim Pratap Singh(Authors)
- 2019(Publication Date)
- Elsevier(Publisher)
A biofilm is formed by single or multiple microbial species on a natural or artificial surface, woven around the self-produced matrix of extracellular polymeric substances (EPSs). Different abiotic and biotic factors affect the formation of Biofilms, such as temperature, water, secretion of EPSs that contain proteins, exopolysaccharides, metal ions, DNA, lipids, and humic substances. The fundamental role of a biofilm formation is social cooperation, nutrient uptake, and protection against different environmental stresses. Biofilm formation takes place in various steps that begin with the attachment of a single cell to a surface, proceeds through the formation of multiple layers of microbial cells, and finally disperses microbes as planktonic cells. Biofilms can be made up of either a single species of microbes, or a combination of many microbial species. Bacteria, fungi, archaea, and diatoms are generally involved in biofilm formation. This microbial community can provide a huge number of benefits, however is not without harmful effects in biofilm form. The advent of new techniques has made it easier to study the complex structure of Biofilms, their nature, role in the environment, and their links to healthcare and a variety of industries.Keywords
Microbial Biofilms; EPS; Quorum sensing; Bacteria11.1 Introduction
11.1.1 What are Biofilms?
A biofilm is a surface-associated well-organized microbial community that is bounded by a polymeric matrix comprising self-producing exopolysaccharides, extracellular DNA (eDNA) and proteins that are associated with an inert or biotic surface (Hall-Stoodley et al., 2004 ; Vlamakis et al., 2013 ; Teschler et al., 2015 ). Microbial Biofilms are enclosed by self-producing extracellular polymeric substances (EPSs) that provide shelter morphology and protection. In comparison to single cells, Biofilms empower organisms to survive and adapt to changing conditions (Costerton et al., 1995 ). A large number of studies have focused on biofilm formation by pathogenic microorganisms, but more recent research reports have emphasized biofilm formation by useful bacteria, for example, the plant growth-promoting bacteria Bacillus subtilis which has emerged as a model to study the biofilm creation mechanisms in soil bacteria (Rosche et al., 2009 ; Vlamakis et al., 2013 ; DeLoughery et al., 2015 ). Microbial biofilm can be found on different surfaces, including indwelling medical devices, living tissues, potable and industrial water pipelines, and many other materials. The interaction of the microbial community at the interface of soil and plant roots is now a major hot spot for the study of Biofilms. The soil area around the plant root is known as the rhizosphere where complex biological and ecological processes take place. It provides a favorable environment for biofilm formation due to the presence of enough moisture and nutrients (Ansari et al., 2017 ). A Biofilms matrix protects microbial cells from different environmental stresses such as antimicrobial substances, osmotic shocks, xdehydration, UV radiation, extreme pH, and predators (Costerton et al., 1987 ; Stewart and Costerton, 2001 ; Romanova et al., 2006
eBook - PDF- R. Kania, B. Ars, R. Kania, B. Ars(Authors)
- 2015(Publication Date)
- SPB Academic Publishing(Publisher)
Biofilm: A new concept The issue of recurrence of inflammation and infection Alan Wilson and J. Christopher Post ▶ To describe the unique characteristics of the biofilm phenotype including structure and cell signaling pathways. ▶ To describe the methods used to study Biofilms. ▶ To describe Biofilms as they relate to disease processes. ▶ To describe emerging antimicrobial strategies with an emphasis on nanotechnology approaches. Objectives Chapter cover photo: 3D architecture of a bacterial biofilm. Reproduced from Kania et al. , Laryngoscope , 118:128–134, 2008. 4. Biofilm: A new concept. The issue of recurrence of inflammation and infection A. Wilson 1 and J.C. Post 2 1 University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; 2 Center for Genomic Sciences, Allegheny Health Network, Pittsburgh, PA, USA. 1. Introduction to Biofilms Biofilms are dynamic, complex communities of bacteria. The communities are self-organized, surface associated and are three-dimensional, often achieving a depth of hundreds of bacteria. Biofilms may form on living (biotic) or non-living (abiotic) surfaces, and can be attached to a substratum or interface or to each other as cell aggregates. The bacteria are encased in a bacterial-synthesized extracellular matrix, known as extracellular polymeric substance (EPS), which is comprised of water, polysaccharides, nucleic acids and proteins. Biofilms can have distinct mushroom, tower and stalk-like structures. Intricate structures are formed inside the biofilm, with channels delivering nutrients and disposing of wastes coursing through the bacteria. Biofilm microenvironments are markedly diverse, with spacial segregation and variations in nutrient availability, pH and oxygen levels. For example, the base of the biofilm is almost completely anoxic, while oxygen availability is much greater at the surface.
eBook - PDFPorous Media
Applications in Biological Systems and Biotechnology
- Kambiz Vafai(Author)
- 2010(Publication Date)
- CRC Press(Publisher)
As electron microscopy developed, a more detailed picture of the structure of microbial Biofilms emerged. The subsequent development of confocal scanning laser microscopy, coupled with fluorescent markers, allowed visualization of live hydrated Biofilms as three-dimensional architecture (Costerton et al. 1995). 4.1.1 What Is a Biofilm? Biofilms may be broadly defined as communities of microbial cells associ-ated with a surface, typically encased in an extracellular matrix (Ghan-noum and O’Toole 2004). This definition is applicable to Biofilms formed on solid–liquid interfaces as well as on semisolid–air interfaces and relates to a wide range of surfaces, including steel pipes, soils, medical implants, bioma-terials, tissues, and epithelial cells. The most abundant Biofilms ( > 90% of microorganisms) are associated with environmental Biofilms found in nature or throughout biotechnological applications (Lens et al. 2003; Tandoi et al. 2006). Studies of these Biofilms were dominated by phenotypic behavior, for example, biofilm life cycle and resistance to antibiotics (O’Toole et al. 2000b; Chandra et al. 2001; Reysenbach and Shock 2002). Ongoing research in the field aims at understanding the community physiology, metabolism, ecology, structure/function relationships, and the role of gene exchange, with the over-all objective of providing a database for the development of efficient strategies to control biofilm development and methods to eradicate them. The number of studies directed toward better understanding of the physical characteristics of biofilm, for example, porosity and three-dimensional structures of Biofilms is substantially low. Porosity of Microbial Biofilms: Biomedical Implications 123 Bulk side 20 µ m 20 µ m 20 µ m 20 µ m 20 µ m (a) (b) FIGURE 4.1 Images of a mature Escherichia coli biofilm on glass substrate from a scanning confocal laser microscopy (SCLM).
eBook - PDF- Sigrun Eick, S. Eick, Sigrun, Eick, Adrian Lussi, Marilia A. R. Buzalaf, Adrian, Lussi, Marilia A.R., Buzalaf, Sigrun, Eick(Authors)
- 2020(Publication Date)
- S. Karger(Publisher)
Biofilm in General Abstract In reality, most microorganisms are not free floating. They exist in Biofilms, a community of many of them from the same species or from other genera and attached to sur-faces. Microorganisms undergo a transition from free-floating, planktonic microorganisms to a sessile, surface-attached one. Contact with a surface induces changes in gene expression, and a strong attachment of microcolo-nies occurs only after a few hours. The maturation of a biofilm is associated with matrix formation. The matrix is of importance as it provides stability and protects against environmental insults, it consists of polysaccharides, wa-ter, lipids, proteins, and extracellular DNA. Biofilms can be found everywhere – in the environment, in water systems – and they play an important role in medicine and den-tistry. In medicine, infections of chronic wounds, of the respiratory tract in cystic fibrosis infections, or when linked with incorporated biomaterial are mostly biofilm associated. In the oral cavity, the most prevalent oral dis-eases, dental caries, and periodontitis are multi-species biofilm-associated diseases. Although not acting alone, key pathogens drive the development of the microbial shift. Microorganisms metabolize sugar and create an Eick S (ed): Oral Biofilms. Monogr Oral Sci. Basel, Karger, 2021, vol 29, pp 1–11 (DOI: 10.1159/000510184) Biofilms Sigrun Eick Department of Periodontology, Laboratory of Oral Microbiology, School of Dental Medicine, University of Bern, Bern, Switzerland acidic environment where aciduric bacteria (including mutans streptococci) become dominant, which leads to the demineralization of enamel and dentine. Porphy-romonas gingivalis causes biofilm dysbiosis in the devel-opment of periodontal disease. Biofilm-associated infec-tions are extremely difficult to treat.
- Steven Lane Percival, James Taggari Walker, Paul R. Hunter(Authors)
- 2000(Publication Date)
- CRC Press(Publisher)
79 6.1 INTRODUCTION Biofilms have been cited in the literature for a number of years, often being defined as, “cells immobilized at a substratum and frequently embedded in an organic polymer matrix of microbial origin.” 1,2 Whilst this definition of a biofilm is acceptably por-trayed as the universally acknowledged biofilm model, slight reclassification has taken place. This occurred in 1995 with the redefinition of Biofilms being “matrix-enclosed bacterial populations adherent to each other and/or to surfaces or interfaces.” 3 Despite ongoing discussions on the so-called biofilm model, the enormous diver-sity of Biofilms evident today suggests that strict phraseology for a constantly chang-ing dynamic ecosystem is not possible. As Stoodley et al. 4 have suggested, it may not seem necessary to “restrict a biofilm model to certain structural constraints but instead look for common features or basic building blocks of Biofilms.” With this in mind, it seems plausible to suggest that Biofilms form different structures and are composed of different microbial consortia dictated by biological and environmental parameters which can quickly respond and adapt both phenotypically, genetically (possibly), and structurally to constantly changing internal and external conditions. Consequently, it seems illogical to suggest that a true biofilm model system can be achieved so that it can be applied to every ecological, industrial, and medical situation. Therefore, the definition of a biofilm has to be kept generalised and could
eBook - PDF- Steven Percival, Keith Cutting(Authors)
- 2010(Publication Date)
- CRC Press(Publisher)
Depending on the site of biofilm formation, Biofilms are complex, with many differ-ent genera, species, and numbers of microorganisms. Collectively, therefore, the bio-film is a microbial community consisting of an array of ecosystems and niches. 101,102 Bacteria that grow in a biofilm can create their own environment, which in turn influences the physiology of its component cells. In medical Biofilms, biofilm struc-ture is substantially influenced by the interaction of particles of the nonmicrobial origin from the host or environment. In the human body, Biofilms on native heart valves provide a clear example of this type of interaction in which bacterial micro-colonies in the biofilm develop in a matrix of platelets, fibrin, and EPS. 103 A fibrin capsule that develops will protect the organisms in these Biofilms from the white blood cells of the host. Biofilms on urinary catheters have been found to contain organisms that have the ability to hydrolyze urea in the urine to form free ammonia through the action of the enzyme urease. The produced ammonia then increases the pH at the biofilm–liquid interface. This has been found to result in the precipitation of minerals such as cal-cium phosphate (hydroxyapatite) and magnesium ammonium phosphate (struvite). 104 These minerals become entrapped in the biofilm and cause encrustation and catheter blockage with subsequent promotion of urinary tract infection. In mature Biofilms of P. aeruginosa, there are substantially different protein pro-files when compared to planktonic bacteria, and in one particular study 105 more than 300 proteins were detectable in mature biofilm samples that were not present in planktonic bacterial cultures. F ACTORS T HAT G OVERN THE D EVELOPMENT OF B IOFILMS Overall, the development of a biofilm is generally governed by a number of param-eters.
- Gero Benckiser, Sylvia Schnell, Gero Benckiser, Sylvia Schnell(Authors)
- 2006(Publication Date)
- CRC Press(Publisher)
131 7 Diversity of Biofilms and Their Formation Processes M.W. Falk and S. Wuertz CONTENTS 7.1 What Constitutes a Biofilm? ................................................................................................ 131 7.2 Origins of Biofilm Research ................................................................................................ 132 7.3 Analytical Tools to Investigate Biofilms .............................................................................. 133 7.4 Highly Structured Biofilm Communities ............................................................................. 135 7.5 Formation and Development of Biofilms in Soil ................................................................ 136 7.6 Prevalence and Diversity of Biofilms in Soil ...................................................................... 138 7.7 Prevalence and Diversity of Biofilms in the Rhizosphere for Agricultural Systems ......... 140 7.8 Additional Areas of Biofilm Interest in Agricultural Systems ............................................ 141 7.9 Conclusions .......................................................................................................................... 141 References ...................................................................................................................................... 142 Over the last decade, the concept of sessile microorganisms possessing a distinct developmental microbial lifestyle has been fully embraced in the disciplines of both microbiology and ecology. Cells adhere to each other at an interface aided by extracellular polymeric substances and develop into assemblages of microcolonies with more or less confluous architecture referred to as Biofilms. While embedded in a biofilm, a cell’s phenotypic expression can be altered to a state not commonly found in planktonic cells (Costerton et al. 1995; Prigent-Combaret et al. 1999; Watnick and Kolter 2000).
eBook - PDFThe Perfect Slime
Microbial Extracellular Polymeric Substances (EPS)
- Hans-Curt Flemming, Thomas R. Neu, Jost Wingender(Authors)
- 2016(Publication Date)
- IWA Publishing(Publisher)
mBio , 5 , e01667–14. Fröls S. (2013). Archeal Biofilms: widespread and complex. Mol. Biol. Archaea , 41 , 393–398. Harrison J. and Turner R. J. (2007). Multimetal resistance and tolerance in microbial Biofilms. Nat. Rev. Microbiol. , 5 , 928–939. Hobley L., et al. (2013). BsIA is a self-assembling bacterial hydrophobin that coats the Bacillus subtilis biofilm. Hobley L., Harkins C., MacPhee C. E. and Stanley-Wall N. R. (2015). Giving structure to the biofilm matrix: an overview of individual strategies and emerging common themes. FEMS J. Microbiol. Rev. , 39 , 649–669. Horikoshi K. (2016). Extremophiles: How It All Began. Springer, Heidelberg, New York, 172pp. Houry A., et al. (2012). Bacterial swimmers that infiltrate and take over the biofilm matrix. Proc. Natl. Acad. Sci. USA , 109 , 13088–13093. Konopka A. (2009). What is microbial community ecology? ISME J. , 3 , 1223–1230. Leon-Morales C. F., Strathmann M., Flemming H.-C. (2007). Influence of Biofilms on the movement of colloids in porous media. Implications for colloid facilitated transport in subsurface environments. Wat. Res. , 41 , 2069–2078. Limoli D. H., Jones C. J. and Wozniak D. J. (2015). Bacterial extracellular polysaccharides in biofilm formation and function. Microbiol. Spectr. , 3 , doi: 10.1128/microbiolspec.MB-0011-2014. Mayer C., Moritz R., Kirschner C., Borchard W., Maibaum R., Wingender J. and Flemming H.-C. (1999). The role of intermolecular interactions: studies on model systems for bacterial Biofilms. Int. J. Biol. Macromol. , 26 , 3–16. McDonogh R., Schaule G. and Flemming H.-C. (1994). The permeability of biofouling layers on membranes. J. Membr. Sci. , 87 , 199–217. The perfect slime – and the “dark matter” of Biofilms 13 Neu T. R. and Lawrence J. (2016). The extracellular matrix – an inextractable part of biofilm systems. In: The Perfect Slime, H.-C. Flemming, T. Neu and J. Wingender, (eds), IWA Publ., London, 25–60. Olsen I.
- Abhilash, B. D. Pandey, K. A. Natarajan(Authors)
- 2015(Publication Date)
- CRC Press(Publisher)
281 11 Role of Natural and Engineered Biofilms Composition in Toxic Inorganic Contaminants Immobilisation Eric D. van Hullebusch and Yoan Pechaud 11.1 What Is a Biofilm? Most of the microorganisms on Earth live in aggregates such as films, flocs, granules and sludges (Costerton et al. 1995). In this chapter, biofilm is defined as a cluster of microorganisms able to multiply and to live in a slimy matrix composed of minerals and microbially synthesised extracellular polymeric substances (EPS). CONTENTS 11.1 What Is a Biofilm? ...................................................................................... 281 11.1.1 Architecture and Dynamics of Biofilms ..................................... 282 11.1.1.1 Processes Involved in Biofilm Development and Maturation ................................................................ 282 11.1.1.2 Overall Biofilm Composition ......................................... 284 11.1.1.3 Chemical, Biological, Biochemical and Physical Heterogeneities ................................................................ 284 11.1.2 Distinction between Natural and Engineered Biofilms ............................................................................................ 285 11.1.2.1 Natural Biofilms (Epilithic Biofilm) .............................. 286 11.1.2.2 Engineered Biofilms ....................................................... 286 11.2 Toxic Inorganic Contaminants Removal Mechanisms in Biofilms .... 288 11.2.1 Case of Heavy Metals .................................................................... 288 11.2.1.1 Biosorption ....................................................................... 289 11.2.1.2 Microbially Induced Metal Precipitation ..................... 291 11.2.2 Metalloids Removal ....................................................................... 292 11.2.2.1 Case of Selenium .............................................................
eBook - PDFBiofilms
Recent Advances in their Study and Control
- L V Evans(Author)
- 2000(Publication Date)
- CRC Press(Publisher)
Reported evidences of spontaneous microbial coaggregation and cell-cell recognition (Kolenbrander and London, 1992; 1993), and cell-cell communication in Biofilms (Davies et al., 1998) were quickly associated with the new biofilm model and hypotheses were suggested regarding the possible role of microcolony structure and internal cell organization in biofilm activity and survival. The journal New Scientist expanded on these hypotheses in an article published in August 1996, and emphatically compared Biofilms to cities built by microorganisms. General expectation among biofilm researchers is that these elaborate microorganism-formed structures have meaning. However, notions endowing Biofilms with abilities to intentionally control these structures, and their environment, should be approached with caution, as there is little experimental evidence to support them. Nevertheless, the unusual propensity of microorganisms to form complex structures on surfaces has been noted by many researchers (Keevil and Walker, 1992; Costerton et al., 1994, Massol- Deya et al., 1994; Wolfaardt et al., 1994; Bishop and Rittmann, 1995), although the reasons for this remain unclear. In natural and engineered systems a spectrum of structurally heterogeneous Biofilms is observed ranging from dense, amorphous Biofilms, which are less structurally heterogeneous, to Biofilms demonstrating robust, well developed structures. This chapter discusses the relations between the structure and function in Biofilms. The popular term biofilm structure means, more often implicitly than explicitly, spatial distribution of biomass density in Biofilms, or, sometimes, the complementary distribution of biofilm porosity. Biofilms with well-developed microcolonies, separated by wide interstitial voids are considered “structurally heterogeneous”, and most of their biomass is concentrated within microcolonies.
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