Caister Academic Press

Aquatic Biofilms: Ecology, Water Quality and Wastewater Treatment

"essential reference book" (Biotechnol. Agron. Soc. Environ.)
"unique environmental focus" (ASM: Small Things Considered)
"an excellent reference book" (Microbiol. Today)
Publisher: Caister Academic Press
Edited by: Anna M. Romaní, Helena Guasch and M. Dolors Balaguer
Campus de Montilivi, University of Girona, Spain
Pages: xii + 230
Publication date: January 2016
ISBN: 978-1-910190-17-3
Price: GB £199 or US $319Buy book or Buy online
Publication date: January 2016
ISBN: 978-1-910190-18-0
Price: US $319Buy ebook

Biofilms in aquatic ecosystems colonize various surfaces (sand, rocks, leaves) and play a key role in the environment. Aquatic biofilms supply energy and organic matter to the food chain, they are important in recycling organic matter and contribute to water quality.

This book is a concise review of the current knowledge on aquatic biofilms with an emphasis on the characteristics and ecology of biofilms in natural ecosystems and a focus on biofilm applications linked to water pollution problems. The volume is divided into three sections: Biofilms Mode of Life; Biofilms and Pollution; and New Technologies using Biofilms. In the first section the aquatic biofilm mode of life is described and reviewed. Key aspects covered include the three-dimensional structure and cell to cell communication of biofilms, their dynamic prokaryotic diversity and their vital role in biogeochemical cycles. In the second part of the book the use of biofilms in water quality is comprehensively covered. Chapters discuss biofilms in water quality, environmental risk assessment, monitoring and ecotoxicological approaches. Further topics include biofilm development in sewage pipes and the potential for microbial transformations in these systems. The final section focuses on important examples of novel technologies based on biofilms for water treatment, including the biodegradation of pollutants, the application of bioelectrogenic biofilms, and the biofilm capacity for nitrogen removal.

With contributions from ecologists, engineers and microbiologists this book presents scientists and technicians with up-to-date knowledge and a clear understanding of aquatic biofilms from different and complementary points of view. An essential reference book for anyone working with biofilms.


"up-to-date knowledge and a clear understanding of aquatic biofilms from different and complementary points of view. An essential reference book for anyone working with biofilms." from Biotechnol. Agron. Soc. Environ.

"provides an ecosystem perspective to a topic that is commonly only considered at the population or community ecology level ... unique environmental focus" from ASM: Small Things Considered

"Aquatic Biofilms is an excellent reference book for students, researchers or scientists ... provides a unique perspective to biofilms in the aquatic environment ... offers a balanced view of aquatic biofilms, spanning from theory to application and from ecology to engineering, ensuring a holistic insight of environmental biofilms." from Microbiology Today

Table of contents
1. Limits of the Biofilm Concept and Types of Aquatic Biofilms
Juanita Mora-Gómez, Anna Freixa, Núria Perujo and Laura Barral-Fraga
Pages: 3-28.
Nowadays, it is widely recognized that in natural aquatic settings bacterial cells are most often found in close association with wet surfaces and interfaces in the form of multicellular aggregates commonly referred to as biofilms, which also involve algae, fungi and protozoa. However, since surface-associated bacteria were first reported, the biofilm concept has been developed to include the great complexity of this microbial way of life. Biofilms in natural and anthropogenic environments are modulated by the nature of the surface in which they grow and environmental factors, which determine the biofilm composition and structure and, in consequence, its metabolism and function. As a consequence there are many types of biofilm and many terms have been used through years to try to describe particular biofilms in relation to a type of surface or environment. In the present review, we summarize the knowledge on biofilms, starting from the origin and evolution of the concept followed by a description of biofilm types based on substratum characteristics. Finally, we explain the general effects of environmental variables, contextualizing them in the wide range of natural aquatic ecosystems (including fresh and marine water) and some manmade systems (such as those associated with water distribution systems and marine environments).
2. Laser Microscopy for the Study of Biofilms: Issues and Options
Thomas R. Neu and John R. Lawrence
Pages: 29-46.
In this review, river biofilms and the various structural aspects of environmental biofilms are discussed. These include sample type and origin, cellular and polymeric constituents as well as examination at the micro- and meso-scale. For this purpose, selected studies are considered taking advantage of the confocal imaging approach for investigation of hydrated environmental biofilm samples. Emphasis is put on extracellular polymeric substances (EPS) as a multi-functional component of microbial biofilms. The main technical focus is on laser scanning microscopy by means of 3-dimensional, multichannel imaging, specific staining techniques and digital image analysis. The advantages and limitations of the approach are critically assessed. Finally, research needs are listed in order to advance understanding of complex, environmental, real world biofilms.
3. Interactions and Communication Within Marine Biofilms
Priyanka Sathe and Sergey Dobretsov
Pages: 47-62.
Biofilms are the prime mode of life for many microbial species and they are omnipresent in aquatic environment. Biofilm's three-dimensional architecture provides the concomitant microbial populations with additional protection from predation and toxic substances. Marine biofilms (often termed as micro-fouling) are composed of different species of bacteria, diatoms and protozoa surrounded by a matrix of extra polymeric substances (EPS). Formation of marine biofilms depends on the species present, their microbial activity and environmental conditions. Marine biofilms attract or repel larvae of invertebrates and spores of macro-algae resulting in formation of macro-fouling communities ultimately leading to biofouling which is ever increasing threat for maritime industry. Function of any biofilm is dependent on symbiotic interactions between microbial communities. These interactions include competition, cooperation, and neutralism. The best studied chemical interaction between microbes is a cell-to-cell signaling mechanism between bacteria which is called quorum sensing (QS). This process is based on production and perception of simple chemical signals (inducers), which at concentrations higher than thresholds ones triggered differential expression of target genes and cascades of chemical reactions. In order to prevent growth of competitors, some microorganism evolved ability to interfere with QS of bacteria. This chapter reviews current understanding of the role of marine microbial communities, interactions between different microorganisms within marine biofilms and novel anti-biofilm strategies.
4. Microbial Biodiversity in Natural Biofilms
Katharina Besemer
Pages: 63-88.
Natural biofilms in aquatic ecosystems exist as complex and dynamic communities, which harbour a considerable microbial biodiversity, typically dominated by Alpha-, Beta- and Gamma-Proteobacteria, Bacteroidetes and Cyanobacteria. A number of publications have highlighted the importance of biofilm biodiversity for ecosystem processes in a range of ecosystems. The aim of this chapter is to give an overview of different aspects of microbial diversity in natural biofilms, including local diversity (alpha-diversity), among-patch diversity (beta-diversity), taxonomic and functional diversity. While its major focus lies on biofilms in the benthic and hyporheic zone of streams and rivers, this chapter also includes examples from lake, tidal and marine sediments, and biofilms associated with suspended aggregates. The local and regional processes that have been proposed to sustain or constrain biofilm biodiversity and community assembly, such as environmental heterogeneity, biotic interactions and dispersal dynamics are reviewed. Finally, this chapter considers the relationship between taxonomic diversity, functional diversity and ecosystem processes.
5. Aquatic Biofilms and Biogeochemical Processes
Laura Leff, Jonathon B. Van Gray, Eugènia Martí, Stephanie N. Merbt and Anna M. Romaní
Pages: 89-108.
In this chapter, we discuss the biogeochemistry of biofilms with an emphasis on the unique features of biofilms that impact oxidation-reduction reactions, such as retention of materials (nutrients, organic molecules, including enzymes), shortened uptake lengths, inter-cellular interactions due to proximity of the organisms, and redox gradients over short spatial distances. Our focus is on carbon, nitrogen and phosphorus with some inclusion of micronutrients. The role of biofilm structure and microbial community composition (including algal-bacterial relationships) in determining the spatiotemporal variations in biogeochemistry is discussed as well as the spatial scales of biogeochemical reactions within biofilms. Methods for measuring biogeochemical processes and environmental conditions in biofilms are reviewed, from molecular tools and fine scale measurements, to large scale biogeochemical measurements in flumes and mesocosms or natural systems. The relevance of the spatial scale is highlighted as well as the challenge for scaling-up of methods.
6. Benthic Diatom Monitoring and Assessment of Freshwater Environments: Standard Methods and Future Challenges
Soizic Morin, Nora Gómez, Elisabet Tornés, Magdalena Licursi and Juliette Rosebery
Pages: 111-124.
Since biofilms integrate the environmental effects of water chemistry, along with the physical and geomorphological characteristics of rivers and lakes, they have been widely applied in biomonitoring. In particular, diatoms are extensively used as reliable environmental indicators. Diatoms are microscopic, unicellular brown algae, which often dominate the algal biomass of biofilms. The shape and morphology of the siliceous skeleton, the frustules, unique to each taxon are used for taxonomical identification. The floras are diverse, in relation to their geographical location (climate, geology, relief) and to the quality of the aquatic environments they inhabit. Indeed, species are sensitive to the water physicochemical parameters and their presence/abundance is therefore correlated to water quality. Diatom sensitivity or tolerance towards different environmental parameters has long been studied and used to implement bioassessment methods. Such methods evolved from indices of saprobity designed first for European streams, to developments of various diatom indicators worldwide, able to highlight different types of pollution (pH, salinity, nutrients, toxicants). The objective of this chapter is to provide scientists and water managers with a broad overview of diatom tools helpful to monitor the ecological status of freshwater environments. We describe the applicability range and the limitations of the main existing methods, metrics (indices, traits) and types of surveys used, as well as the challenges faced by scientists to improve routine biomonitoring.
7. The Use of Biofilms to Assess the Effects of Chemicals on Freshwater Ecosystems
Helena Guasch, Joan Artigas, Berta Bonet, Chloe Bonnineau, Oriol Canals, Natàlia Corcoll, Arnaud Foulquier, Julio López-Doval, Sandra Kim-Tiam, Soizic Morin, Enrique Navarro, Stephane Pesce, Lorenzo Proia, Humbert Salvadó and Alexandra Serra
Pages: 125-144.
Nowadays, biofilms are one of the principal targets of community ecotoxicology in aquatic ecosystems with a high potential for future use in ecotoxicology. A large set of methods derived from biofilm ecology has successfully been applied in ecotoxicology providing a diverse and comprehensive toolbox. Our ability to quantify the effects of pollution on different biofilm components, allows the direct effects of pollutants on the most sensitive community and their indirect effects on the rest of biofilm components to be evaluated. Biofilms are also a site for biotransfomation and/or transfer of chemicals to other aquatic organisms, supporting a more generalized use of biofilms in environmental chemistry. Investigations aiming to describe processes at biofilm scale, like nutrient dynamics and those including simple food chains, have recently been applied, providing the opportunity of upscaling the effects of pollutants on biofilms to food webs and ecosystems. Finally, biofilm ecotoxicology should now focus on providing the theoretical background for understanding the complex set of responses of natural communities to pollution. This knowledge should also be the basis for guiding the selection of the most appropriate tools and the development of new approaches for a better detection of the impact of pollution on aquatic life.
8. Biofilm Development in Sewer Networks
Oriol Gutierrez, Guangming Jiang, Keshab Sharma and Zhiguo Yuan
Pages: 145-164.
Wastewater collection systems, or sewers, are crucial sections of the urban water cycle where complex microbial, chemical and physicochemical processes take place. This chapter aims to give an overview of the diversity and importance of biofilms and bioreactions occurring in sewers, paying special attention to its detrimental effects. Sewer biofilms can be divided in two main classes: (1) Submerged biofilms: including activities of Sulfate Reducing Bacteria (SRB) responsible for the formation of sulfide (H2S, an odorous, toxic and corrosion-inducer compound), Methanogenic Archaea (MA) responsible for the formation of methane (CH4, an explosive and potent greenhouse gas) and the Fermentation processes that increase the two previous biofilms metabolism. (2) Unsubmerged biofilms: activities of biofilms growing on the gas phase of sewers that causes loss of concrete mass, cracking of the sewer pipes and ultimately, structural collapse. This process is known as microbially induced concrete corrosion (MICC). The structure of sewer-biofilms and mechanisms for the control of its harmful effects are described.
9. Biofilm Biodegradation Potential
Freshta Akbari, Natasha Andrade, Merily Horwat and Birthe V. Kjellerup
Pages: 167-182.
Persistent organic pollutants (POPs) are present in the environment after decades of industrial activity and have contaminated soils and sediments worldwide. The group of contaminants described as POPs includes toxic compounds such as polychlorinated biphenyls (PCBs), dioxins, chlorinated ethenes and polycyclic aromatic hydrocarbons (PAHs) and brominated flame retardants. Bioremediation of POPs utilizing microbial communities in the biofilm mode of growth has enhanced the removal of POPs from the environments most often converting the organic pollutants to harmless materials. The state-of-the-art for biofilm based solutions for biodegradation of POPs is primarily based on laboratory experiments often performed at optimal conditions. Thus the influence of natural conditions such as nutrient requirement, bioavailability, life style and physic-chemical conditions might vary depending on the POP in question and the environment such as co-contaminants. Field studies of biofilm based solutions are becoming more frequent and most seem promising. Along with these studies knowledge about the mechanisms by which either indigenous or bioaugmented microorganisms forming biofilms enhancing bioremediation is increasingly being expanded.
10. Electroactive Biofilms in Water and Air Pollution Treatment
Anna Vilajeliu-Pons, Sebastià Puig, Alessandro Carmona-Martínez, Nicola Bernet, Marta Coma, Federico Aulenta, Jesús Colprim and Maria Dolors Balaguer
Pages: 183-204.
Biofilms are used in wastewater treatment and in the production of valuable compounds. Bioelectrochemical system (BES) technology represents one practical application of biofilms. In these systems, bioelectrogenic biofilms are a bacterial consortium capable of performing electron transfer to the conductive material on which they are grown. This capacity of these organisms has been used in environmental biotechnology to couple pollutant removal, mainly from water but also from air streams, for the production of energy or valuable products. The following chapter outlines the details of such a consortium, highlighting the mechanisms of extracellular electron transfer and their main applications.
11. Biofilms for One-stage Autotrophic Nitrogen Removal
Jose M Carvajal-Arroyo, Tiago Rogeiro Vitor Akaboci, Maël Ruscalleda, Jesus Colprim, Emilie Courtens and Siegfried E. Vlaeminck
Pages: 205-222.
About 20 years after the discovery of microbial anoxic ammonium oxidation (anammox), the autotrophic nitrogen removal through partial nitritation-anammox (PNA) for ammoniacal wastewater treatment has become a mature technology. The application of these slow growing anoxic ammonium-oxidizing bacteria (AnAOB) requires engineered systems with efficient biomass retention. In the last decade, several one-stage PNA technologies have been developed that promote the growth of AnAOB in biofilms along with aerobic ammonium-oxidizing bacteria (AerAOB). Such biofilms grow on the surface of a carrier material or in mm-scale bio-aggregates (granules). Thanks to the easy retention of biofilm carriers or good settleability of granules, long sludge retention times can be maintained. Additionally, diffusional oxygen transfer limitation within the biofilm allows for the creation of aerobic and anoxic microniches where AerAOB and AnAOB, respectively, can thrive. This chapter describes and discusses the engineering and ecological characteristics of the different technologies developed so far, including rotating biological contactors (RBC), moving bed biofilm reactors (MBBR), membrane-aerated biofilm reactors (MABR) and granular systems. Moreover, the recent literature on operation parameters that influence the greenhouse gas emissions (i.e., N2O) during PNA are described . Finally the future trends in the biofilm-PNA applications to new effluents, with special attention to mainstream sewage treatment, are discussed.

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(EAN: 9781910190173 9781910190180 Subjects: [microbiology] [bacteriology] [environmental microbiology] [biofilms] )