Publisher: Caister Academic Press
Editor: Gavin Lear and Gillian D. Lewis Lincoln University, Christchurch, New Zealand and University of Auckland, New Zealand (respectively)
Publication date: February 2012 Available now!
Price: GB £159 or US $319 (hardback)
Pages: x + 228
"Highly recommended is the chapter on interactions between plants and biofilms" from Hans-Curt Flemming (Duisburg, Germany) writing in Biospektrum (2012) 18: 109.
"the book comprises 11 papers addressing different applications of biofilm research ... each paper provides a useful update/review of a given area - I particularly like the interactions described in the quorum sensing paper." from Joanna Verran, Manchester Metropolitan University, UK writing in Microbiology Today (2012)
Quorum Sensing and Social Interactions in Microbial Biofilms
Robert J. Goldstone, Roman Popat, Matthew P. Fletcher, Shanika A. Crusz and Stephen P. Diggle
It is now well recognised that populations of bacteria from many Gram-positive and Gram-negative species cooperate and communicate to perform diverse social behaviours including swarming, toxin production and biofilm formation. Communication between bacterial cells involves the production and detection of diffusible signal molecules and has become commonly known as quorum sensing (QS). In addition, an evolutionary perspective on QS illuminates important phenomena which help in understanding the prevalence and diversity of QS phenotypes and strategies under various conditions. The research fields of QS and biofilm formation often overlap with a number of studies demonstrating that QS is an important regulatory mechanism of biofilm formation in a variety of bacterial species. However in contrast, there are conflicting reports, demonstrating that QS appears to play a minimal role in the development of biofilms. Our aim in this review is to highlight the key findings with respect to QS and the subsequent impact on biofilm formation. We also discuss QS and cooperation in the context of social evolution and how this may impact on the development and maintenance of microbial biofilms.
Biofilms in Disease
James D. Bryers
Clinically related research on biofilms has expanded exponentially in the past ten years due to the pandemic of nosocomial (hospital-related) infections. Biofilms are thought to cause a significant amount of all human microbial infections, according to the Centers for Disease Control and Prevention. Nosocomial infections are the fifth leading cause of death in the U.S. with more than two million cases annually (or approximately 10% of American hospital patients). The difficulty of eradicating biofilm bacteria with classic systemic antibiotic treatments is a prime concern of medicine. Biofilm bacteria can be up to a thousand times less susceptible to antimicrobial stress than their freely suspended counterparts. This chapter discusses the pathogenesis of a number of biofilm-mediated infections, including: oral infections, biomedical device based infections, osteomyelitis, otitis media, and others. Emerging research in biofilm control and prevention is also reviewed.
The Ecological Significance of Plant-associated Biofilms
Venkatachalam Lakshmanan, Amutha Sampath Kumar and Harsh P. Bais
Microorganisms have historically been studied as planktonic or free-swimming cells, but most exist as sessile communities attached to surfaces, in multicellular assemblies known as biofilms. In the process of coping with both the pathogenic and beneficial interactions, the rhizosphere of plant roots encourages formation of sessile communities that begins with the attachment of free-floating microorganisms to a surface. Certain bacteria such as plant growth promoting rhizobacteria not only induce plant growth but also protect plants from soil-borne pathogens in a process known as biocontrol. Contrastingly, other rhizobacteria in a biofilm matrix may cause pathogenesis in plants. Although research suggests that biofilm formation on plants is associated with biological control and pathogenic response, little is known about how plants regulate this association. The scope of this chapter is restricted to biofilm-forming bacteria and their interactions with terrestrial plants, specifically emphasizing recent work. After an overview of documented interactions between bacteria and plant tissues, we examine some of the more prominent mechanisms of biofilm formation on and around plant surfaces.
An Invisible Workforce: Biofilms in the Soil
Mette Burmølle, Annelise Kjøller and Søren J. Sørensen
Biofilms in soil are composed of multiple species microbial consortia attached to soil particles and biotic surfaces including roots, fungal hyphae and decomposing organic material. The bacteria present in these biofilms gain several advantages including protection from predation, desiccation and exposure to antibacterial substances, and optimized acquisition of nutrients released in the mycosphere. Studies of soil biofilms are complicated by the composite structure of the soil environment; therefore, various simplified model systems have been applied to study succession and bacterial interactions in soil biofilms. Model system observations indicate an increased efficiency to degrade and decompose organic material and xenobiotic compounds by these multispecies bacterial communities. Consequently, soil biofilms may be valuable tools for bioremediation and biocontrol. However, soil biofilms may also provide survival sites for opportunistic pathogenic bacteria, providing enhanced protection and increasing their potential to survive and evolve in the soil environment. In this review, we provide evidence that biofilms are of major importance for the fitness of individual bacteria and the wider soil ecology, due to the accumulated selective advantage provided to bacteria by the biofilm mode-of-life.
Biofilms: Applications in Bioremediation
Gabriele Pastorella, Giulio Gazzola, Seratna Guadarrama and Enrico Marsili
Bioremediation uses microorganisms to remove, detoxify, or immobilize pollutants, and does not require addition of harmful chemicals. Bioremediation is particularly suitable for large areas where contaminant concentrations are relatively low and the hydrology of the soil does not support an aggressive chemical remediation strategy. In the last few years, researchers have described the mechanisms of bioremediation for numerous priority pollutants, including chlorinated hydrocarbons, polyaromatic hydrocarbons, and heavy metals. However, most studies published to date have dealt with planktonic cultures grown under controlled laboratory conditions. Microorganisms in the environment occur mostly as biofilms, whose development is encouraged by the presence of solid surfaces and the limited amounts of organic carbon. Therefore, optimization of bioremediation processes in the field requires a thorough knowledge of biofilm structure, dynamic, and interaction with pollutants and other environmental factors. In this chapter, we describe the recent advances in bioremediation, with particular regard to the role of microbial biofilms. We discuss emerging technologies, such as bioelectroremediation and microbially produced surfactants. We also show how genetic engineering technologies may be employed to improve bioremediation effectiveness, both in laboratory and in field applications.
Biofilms in Wastewater Treatment Systems
G.A. Clark Ehlers and Susan J. Turner
Biofilms occur frequently inside various engineered systems for wastewater treatment. These include traditional trickling filter systems, modified lagoons, and specialized supplementary systems for nutrient removal or treatment of specialized wastes. The major advantages of biofilm systems over suspension treatment is the high microbial density that can be achieved, leading to smaller treatment system footprints, and the inherent development of aerobic, anoxic and anaerobic zones which enable simultaneous biological nutrient removal. The intrinsic resistance of biofilm communities to changing environmental conditions creates the added advantage that biofilm-based treatment systems are more resilient to influent variation in toxicity and nutrient concentrations. In contrast to biofilms of environmental or biomedical relevance comparatively little is known about development and stability in waste treatment systems. The advent of tools that enable the study of biofilms in reactor systems on a molecular level has enabled greater insight into the physiologically and biochemically relevant pathways that may facilitate optimized processes. In this chapter, the current literature on biofilms in wastewater treatment systems is reviewed and opportunities for further development in this field are identified.
Corrosion and Fouling
Steve Flint and Gideon Wolfaardt
Biofilms can directly or indirectly be attributed to deterioration of the underlying substratum. Corrosion may result, particularly if the surface comprises metal or metal alloy. This phenomenon, referred to as microbially influenced corrosion (MIC) affects many industries from food manufacture to medicine. The economic impact of corrosion is significant due to the need for replacing corroded equipment, repairs and attempts to prevent corrosion. MIC is believed to be responsible for one third of all metallic corrosion. Although there have been many studies into the mechanisms of MIC, the process is relatively poorly understood. Most information relates to pure cultures, however biofilms are rarely composed of single species thus most models are a simplification of the real process. It is likely the MIC depends on the composition of the biofilm and the environment surrounding the biofilm. Prevention and control methods rely on mechanical cleaning of fouling and chemical removal and killing of biofilms. Future control measures are likely to focus on preventing biofilm formation.
Biofilms in Freshwater: Their Importance for the Maintenance and Monitoring of Freshwater Health
Gavin Lear, Andrew Dopheide, Pierre-Yves Ancion, Kelly Roberts, Vidya Washington, Jo Smith and Gillian D. Lewis
This chapter reviews our current understanding of the roles biofilm-associated microbial communities play in both maintaining and improving the ecological health of freshwater rivers and streams. Biofilms are where most of the bacteria present in freshwater systems are found, and have been identified as major sites for primary production, carbon and nutrient cycling. Advances in various scientific methodologies have recently been used to characterise the enormous diversity of biofilms, in terms of their structural, chemical and biological traits. The microbial life present within most natural biofilms, as well as associated exudates and lysates have been identified as a valuable, nutrient rich food source for a variety of benthic consumers. Furthermore, the diverse metabolic potential of these complex communities, in combination with various protective traits offered by the biofilm 'mode-of-life', provide biofilms with an excellent ability to degrade, or otherwise transform a vast array of freshwater pollutants. Despite this apparent resilience, we highlight the sensitivity of these poorly studied freshwater biofilm communities to various human activities, and consider their potential as a reliable and sensitive biological indicator of freshwater ecological health.
Extracellular Enzymes in Aquatic Biofilms: Microbial Interactions Vs Water Quality Effects in the Use of Organic Matter
Anna M. Romaní, Joan Artigas and Irene Ylla
Biofilms in aquatic ecosystems colonize various compartments (sand, rocks, leaves) and play a key role in the uptake of inorganic and organic nutrients. Due to their extracellular enzyme capabilities, biofilm microorganisms are able to use organic matter from the surrounding water and increasing activities are related to the availability of biodegradable organic carbon. The most common extracellular enzymes analysed are those involved in the decomposition of polysaccharides, peptides and organic phosphorus compounds, and changes in enzyme expression have been related to the use of different sources of organic matter available in the ecosystem (i.e., during drought-storm and/or pollution episodes). Enzymes important for microbial acquisition of nitrogen and phosphorus also respond to nutrient content and/or imbalances in the flowing water. Additionally, biofilm extracellular enzyme activities are modified by the internal recycling of organic matter and microbial interactions (competition/synergism) within the biofilm, such as algal-bacterial and fungal-bacterial interactions. Although an extensive knowledge of the biofilm structure is required for the interpretation of extracellular enzyme activities in aquatic biofilms, they give a very useful, integrative measure of the biofilm community function in relation to organic matter use and cycling.
Energy from Slime? Power from Microbial Fuel Cells
Koichi Nishio, Atsushi Kouzuma, Souichiro Kato and Kazuya Watanabe
Microbial fuel cells (MFCs) are devices that exploit microbial catabolic activities to generate electricity from a variety of starting materials, including complex organic waste and renewable biomass. The use of these energy sources provides MFCs with a great advantage over chemical fuel cells that utilize only purified reactive fuels (e.g., hydrogen). In an MFC bioreactor, microbes that respire using an anode with organics as electron donors grow preferentially, resulting in accelerated and increased current generation with time. The placement of an anode in either soil or sediment represents a simplified MFC system, known as a sediment MFC, which generates current as soil microbes utilize the anode as an electron acceptor. In addition, the irradiation of an MFC system results in the proliferation of photosynthetic microbes together with anode-respiring microbes, resulting in the syntrophic conversion of light energy into electricity. These examples demonstrate that the MFC system is based on a variety of fundamental and sustainable bioenergy processes, and we suggest that a deeper understanding of how microbes transfer electrons to anodes is essential for further developments of MFC systems.
Catalytic Biofilms: a Powerful Concept for Future Bioprocesses
Rainer Gross, Andreas Schmid and Katja Buehler
Biofilms are mainly known for causing problems in medical and industrial settings due to their persistence towards treatment with bactericides, including antibiotics. However, in the area of bioremediation they are widely recognized for their ability to degrade hazardous or organic compounds to CO2 and biomass. Biofilms represent a highly interesting biological concept since they unite important characteristics such as the ability of self-immobilization and increased robustness to various physical, chemical and biological stressors, which make them exceedingly attractive for productive catalysis. The following review provides a detailed survey of biofilm applications for productive biocatalysis on lab-, pilot-, and industrial scales, regarding fermentation as well as biotransformation reactions. It discusses technological as well as biological challenges of biofilm driven catalysis, presenting developments in the field of biofilm reactor technology and the latest findings in understanding biofilm dynamics. Biocatalysis related issues like genetic stability, evolution, uncontrolled growth as well as detachment, contamination risks, monitoring of biomass, EPS, chemical and biological heterogeneity are considered.
(EAN: 9781904455967 Subjects: [microbiology] [bacteriology] [medical microbiology] [molecular microbiology] [environmental microbiology] )