Microbial Ecology of Wastewater Treatment Plants

Microbial Ecology of Wastewater Treatment Plants
Author: Maulin P. Shah,Susana Rodriguez-Couto
Publsiher: Elsevier
Total Pages: 570
Release: 2021-05-15
ISBN: 0128225041
Category: Technology & Engineering
Language: EN, FR, DE, ES & NL

Microbial Ecology of Wastewater Treatment Plants Book Excerpt:

Microbial Ecology of Wastewater Treatment Plants presents different methods and techniques used in microbial ecology to study the interactions and evolution of microbial populations in WWTPs, particularly the new molecular tools developed in the last decades. These molecular biology-based methods (e.g. studies of DNA, RNA and proteins) provide a high resolution of information compared to traditional ways of studying microbial wastewater populations, such as microscopic examination and culture-based methods. In addition, this book addresses the ability of microorganisms to degrade environmental pollutants. Describes application of different Omics tools in Wastewater treatment plants (WWTPs) Demonstrates the role of microorganisms in WWTPs Includes discussions on the microbial ecology of WWTPs Covers the microbial diversity of activated sludge Emphasizes cutting-edge molecular tools

Microbial Ecology of Activated Sludge

Microbial Ecology of Activated Sludge
Author: Robert Seviour,Per Halkjaer Nielsen
Publsiher: IWA Publishing
Total Pages: 685
Release: 2010-01-15
ISBN: 1843390329
Category: Science
Language: EN, FR, DE, ES & NL

Microbial Ecology of Activated Sludge Book Excerpt:

Microbial Ecology of Activated Sludge, written for both microbiologists and engineers, critically reviews our current understanding of the microbiology of activated sludge, the most commonly used process for treating both domestic and industrial wastes. The contributors are all internationally recognized as leading research workers in activated sludge microbiology, and all have made valuable contributions to our present understanding of the process. The book pays particular attention to how the application of molecular methods has changed our perceptions of the identity of the filamentous bacteria causing the operational disorders of bulking and foaming, and the bacteria responsible for nitrification and denitrification and phosphorus accumulation in nutrient removal processes. Special attention is given to how it is now becoming possible to relate the composition of the community of microbes present in activated sludge, and the in situ function of individual populations there, and how such information might be used to manage and control these systems better. Detailed descriptions of some of these molecular methods are provided to allow newcomers to this field of study an opportunity to apply them in their research. Comprehensive descriptions of organisms of interest and importance are also given, together with high quality photos of activated sludge microbes. Activated sludge processes have been used globally for nearly 100 years, and yet we still know very little of how they work. In the past 15 years the advent of molecular culture independent methods of study have provided tools enabling microbiologists to understand which organisms are present in activated sludge, and critically, what they might be doing there. Microbial Ecology of Activated Sludge will be the first book available to deal comprehensively with the very exciting new information from applying these methods, and their impact on how we now view microbiologically mediated processes taking place there. As such it will be essential reading for microbial ecologists, environmental biotechnologists and engineers involved in designing and managing these plants. It will also be suitable for postgraduate students working in this field.

Development in Wastewater Treatment Research and Processes

Development in Wastewater Treatment Research and Processes
Author: Maulin P. Shah,Susana Rodriguez-Couto
Publsiher: Elsevier
Total Pages: 486
Release: 2022-05-12
ISBN: 032398505X
Category: Science
Language: EN, FR, DE, ES & NL

Development in Wastewater Treatment Research and Processes Book Excerpt:

Development in Wastewater Treatment Research and Processes: Microbial Ecology, Diversity and Functions of Ammonia Oxidizing Bacteria covers up-to-date research on ammonia oxidizing bacteria and their application for the removal of ammonia nitrogen from wastewater treatment plants (WWTPs), discussing remaining gaps in their biology and functions. In this sense, this book features the application of the newly developed omics tools in order to develop less energy intensive and cost-effective biological processes for nitrogen removal from WWTPs. This makes this book an essential and unique book for advanced students, research scientists, environmental agencies and industries involved in wastewater treatment. Covers the application of different omics tools for studying the microbial ecology, diversity and function of ammonia oxidizing bacteria in wastewater treatment plants (WWTPs) Describes the role of ammonia oxidizing microorganisms in WWTPs Presents the microbial ecology of ammonia oxidizing bacteria in WWTPs Includes the microbial diversity of ammonia oxidizing bacteria Emphasizes important aspects of cutting-edge molecular tools in the study of metabolic pathways of ammonia oxidizing bacteria

Advances in Microbial Ecology

Advances in Microbial Ecology
Author: J.G. Jones
Publsiher: Springer Science & Business Media
Total Pages: 416
Release: 2013-11-11
ISBN: 1468477242
Category: Medical
Language: EN, FR, DE, ES & NL

Advances in Microbial Ecology Book Excerpt:

There were many who joked when we took over Advances in Microbial Ecology at Volume 13; perhaps they should have reserved their expressions of superstition for Volume 14. As an example of British understatement, I think it would be fair to say that we have had a little bad luck. Never have I known a volume so bedeviled with misfortune, but we have been similarly fortunate in the patience exhibited by our authors, particularly those who were "first in line" with their chapters. It would be inappropriate to burden the reader with the catalogue of accidents and illnesses; suffice it to say that considerable experience has been gained in contingency planning. We feel particularly delighted that the final product is a balanced volume, maintaining the tradition of Advances in Microbial Ecology in providing something for everyone. The chapters range from the strategies of growth to the role of microbes in maintaining sustainable agriculture, the significance of a single biochemical process to the complexities of coping with a wide range of substrates.

Relationship Between Microbes and the Environment for Sustainable Ecosystem Services Volume 2

Relationship Between Microbes and the Environment for Sustainable Ecosystem Services  Volume 2
Author: Jastin Samuel,Ajay Kumar,Joginder Singh
Publsiher: Elsevier
Total Pages: 352
Release: 2022-08-26
ISBN: 0323910572
Category: Science
Language: EN, FR, DE, ES & NL

Relationship Between Microbes and the Environment for Sustainable Ecosystem Services Volume 2 Book Excerpt:

Relationship Between Microbes and Environment for Sustainable Ecosystem Services, Volume Two: Microbial Mitigation of Waste for Sustainable Ecosystem Services promotes advances in sustainable solutions, value-added products, and fundamental research in microbes and the environment. Topics include advanced and recent discoveries in the use of microbes for sustainable development. Volume Two describes the successful application of microbes and their derivatives for waste management of potentially toxic and relatively novel compounds. This proposed book will be helpful to environmental scientists, experts and policymakers working in the field of microbe- based mitigation of environmental wastes. The book provides reference information ranging from the description of various microbial applications for the sustainability in different aspects of food, energy, environment industry and social development. Covers the latest developments, recent applications and future research avenues in microbial biotechnology for sustainable development Includes expressive tables and figures with concise information about sustainable ecosystem services Provides a wide variety of applications and modern practices of harnessing the potential of microbes in the environment

Environmental Microbiology and Microbial Ecology

Environmental Microbiology and Microbial Ecology
Author: Larry L. Barton,Robert J. C. McLean
Publsiher: John Wiley & Sons
Total Pages: 464
Release: 2019-01-09
ISBN: 1118966279
Category: Science
Language: EN, FR, DE, ES & NL

Environmental Microbiology and Microbial Ecology Book Excerpt:

An authoritative overview of the ecological activities of microbes in the biosphere Environmental Microbiology and Microbial Ecology presents a broad overview of microbial activity and microbes' interactions with their environments and communities. Adopting an integrative approach, this text covers both conventional ecological issues as well as cross-disciplinary investigations that combine facets of microbiology, ecology, environmental science and engineering, molecular biology, and biochemistry. Focusing primarily on single-cell forms of prokaryotes — and cellular forms of algae, fungi, and protozoans — this book enables readers to gain insight into the fundamental methodologies for the characterization of microorganisms in the biosphere. The authors draw from decades of experience to examine the environmental processes mediated by microorganisms and explore the interactions between microorganisms and higher life forms. Highly relevant to modern readers, this book examines topics including the ecology of microorganisms in engineered environments, microbial phylogeny and interactions, microbial processes in relation to environmental pollution, and many more. Now in its second edition, this book features updated references and major revisions to chapters on assessing microbial communities, community relationships, and their global impact. New content such as effective public communication of research findings and advice on scientific article review equips readers with practical real-world skills. Explores the activities of microorganisms in specific environments with case studies and actual research data Highlights how prominent microbial biologists address significant microbial ecology issues Offers guidance on scientific communication, including scientific presentations and grant preparation Includes plentiful illustrations and examples of microbial interactions, community structures, and human-bacterial connections Provides chapter summaries, review questions, selected reading lists, a complete glossary, and critical thinking exercises Environmental Microbiology and Microbial Ecology is an ideal textbook for graduate and advanced undergraduate courses in biology, microbiology, ecology, and environmental science, while also serving as a current and informative reference for microbiologists, cell and molecular biologists, ecologists, and environmental professionals.

Microbial Ecology of Aerial Plant Surfaces

Microbial Ecology of Aerial Plant Surfaces
Author: Mark J. Bailey
Publsiher: CABI
Total Pages: 347
Release: 2006-01-01
ISBN: 1845930614
Category: Science
Language: EN, FR, DE, ES & NL

Microbial Ecology of Aerial Plant Surfaces Book Excerpt:

This book focuses on the ecology of the microbiology of the surfaces of above-ground, aerial portion of vascular plants (including stem, leaves, fruits and flowers), collectively known as the phylloplane. It is divided into 6 sections, highlighting both the value of this highly diverse habitat to research in microbiology and the importance of this research to plant health and ecosystem functions. Section I concerns the biodiversity and population genetics of phyllosphere communities. Section II concerns the spatial distribution and biofilm structures of microbes on the phylloplane. Section III concerns biological control and pathogenicity. Section IV describes gene expression and phyllosphere genomics. Section V focuses on leaf colonization and dispersal. Section VI deals with aerobiology and plant surface microbiology.

Advances in Gram Negative Oxygenic Photosynthetic Bacteria Research and Application 2012 Edition

Advances in Gram Negative Oxygenic Photosynthetic Bacteria Research and Application  2012 Edition
Author: Anonim
Publsiher: ScholarlyEditions
Total Pages: 239
Release: 2012-12-26
ISBN: 146499675X
Category: Science
Language: EN, FR, DE, ES & NL

Advances in Gram Negative Oxygenic Photosynthetic Bacteria Research and Application 2012 Edition Book Excerpt:

Advances in Gram-Negative Oxygenic Photosynthetic Bacteria Research and Application / 2012 Edition is a ScholarlyBrief™ that delivers timely, authoritative, comprehensive, and specialized information about Gram-Negative Oxygenic Photosynthetic B in a concise format. The editors have built Advances in Gram-Negative Oxygenic Photosynthetic Bacteria Research and Application / 2012 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Gram-Negative Oxygenic Photosynthetic B in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Advances in Gram-Negative Oxygenic Photosynthetic Bacteria Research and Application / 2012 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.

Removal of Refractory Pollutants from Wastewater Treatment Plants

Removal of Refractory Pollutants from Wastewater Treatment Plants
Author: Maulin P. Shah
Publsiher: CRC Press
Total Pages: 582
Release: 2021-10-07
ISBN: 1000435261
Category: Technology & Engineering
Language: EN, FR, DE, ES & NL

Removal of Refractory Pollutants from Wastewater Treatment Plants Book Excerpt:

This book discusses new and innovative trends and techniques in the removal of toxic and or refractory pollutants through various environmental biotechnological processes from wastewater, both at the laboratory and industrial scale. It focuses primarily on environmentally-friendly technologies which respect the principles of sustainable development, including the advanced trends in remediation through an approach of environmental biotechnological processes from either industrial or sewage wastewater. Features: Examines the fate and occurrence of refractory pollutants in wastewater treatment plants (WWTPs) and the potential approaches for their removal. Highlights advanced remediation procedures involving various microbiological and biochemical processes. Assesses and compares the potential application of numerous existing treatment techniques and introduces new, emerging technologies. Removal of Refractory Pollutants from Wastewater Treatment Plants is suitable for practicing engineers, researchers, water utility managers, and students who seek an excellent introduction and basic knowledge in the principles of environmental bioremediation technologies.

Wastewater Treatment

Wastewater Treatment
Author: Maulin P. Shah,Angana Sarkar,Sukhendu Mandal
Publsiher: Elsevier
Total Pages: 596
Release: 2021-01-30
ISBN: 0128218959
Category: Technology & Engineering
Language: EN, FR, DE, ES & NL

Wastewater Treatment Book Excerpt:

Wastewater Treatment: Cutting-Edge Molecular Tools, Techniques and Applied Aspects reports new findings in existing molecular biology strategies, including their limitations, challenges and potential application to remove environmental pollutants through advancements made in cutting edge tools. In addition, the book introduces new trends and advances in environmental bioremediation with thorough discussions on recent developments in this field. Describes the application of different omics tools in wastewater treatment plants (WWTPs) Describes the role of microorganisms in WWTPs Points out the reuse of treated wastewater through emerging technologies Includes the recovery of resources from wastewater Emphasizes the need for the use of cutting-edge molecular tools

Anthropogenic Impacts on the Microbial Ecology and Function of Aquatic Environments

Anthropogenic Impacts on the Microbial Ecology and Function of Aquatic Environments
Author: Maurizio Labbate,Justin R. Seymour,Federico Lauro,Mark V. Brown
Publsiher: Frontiers Media SA
Total Pages: 250
Release: 2016-09-06
ISBN: 2889199398
Category: Microbiology
Language: EN, FR, DE, ES & NL

Anthropogenic Impacts on the Microbial Ecology and Function of Aquatic Environments Book Excerpt:

Aquatic ecosystems are currently experiencing unprecedented levels of impact from human activities including over-exploitation of resources, habitat destruction, pollution and the influence of climate change. The impacts of these activities on the microbial ecology of aquatic environments are only now beginning to be defined. One of the many implications of environmental degradation and climate change is the geographical expansion of disease- causing microbes such as those from the Vibrio genus. Elevating sea surface temperatures correlate with increasing Vibrio numbers and disease in marine animals (e.g. corals) and humans. Contamination of aquatic environments with heavy metals and other pollutants affects microbial ecology with downstream effects on biogeochemical cycles and nutrient turnover. Also of importance is the pollution of aquatic environments with antibiotics, resistance genes and the mobile genetic elements that house resistance genes from human and animal waste. Such contaminated environments act as a source of resistance genes long after an antibiotic has ceased being used in the community. Environments contaminated with mobile genetic elements that are adapted to human commensals and pathogens function to capture new resistance genes for potential reintroduction back into clinical environments. This research topic encompasses these diverse topics and describes the affect(s) of human activity on the microbial ecology and function in aquatic environments and, describes methods of restoration and for modelling disturbances.

Fundamental Research Needs for Water and Wastewater Treatment Systems

Fundamental Research Needs for Water and Wastewater Treatment Systems
Author: Anonim
Publsiher: Unknown
Total Pages: 116
Release: 1977
ISBN: 1928374650XXX
Category: Sewage
Language: EN, FR, DE, ES & NL

Fundamental Research Needs for Water and Wastewater Treatment Systems Book Excerpt:

Molecular Microbial Ecology

Molecular Microbial Ecology
Author: Mark Osborn,Cindy Smith
Publsiher: Garland Science
Total Pages: 256
Release: 2004-03-01
ISBN: 0203503392
Category: Science
Language: EN, FR, DE, ES & NL

Molecular Microbial Ecology Book Excerpt:

Microoganisms are distributed across every ecosystem, and microbial transformations are fundamental to the operation of the biosphere. Microbial ecology is the study of this interaction between microorganisms and their environment, and arguably represents one of the most important areas of biological research. Yet for many years our study of microbial flora was severely limited: the primary method of culturing microorganisms on media allowed us to study only between 0.1 and 10% of the total microbial flora in any given environment. Molecular Microbial Ecology gives a comprehensive guide to the recent revolution in the study of microorganisms in the environment. Details are given on molecular methods for isolating some of the previously uncultured and numerically dominant microbial groups. PCR-based approaches to studying prokaryotic systematics are described, including ribosomal RNA analysis and stable isotope probing. Later chapters cover DNA hybridisation techniques (including fluorescent in situ hybridisation), as well as genomic and metagenomic approaches to microbial ecology. Gathering together some of the world’s leading experts, this book provides an invaluable introduction to the modern theory and molecular methods used in studying microbial ecology.

Encyclopedia of Ecology

Encyclopedia of Ecology
Author: Anonim
Publsiher: Newnes
Total Pages: 3120
Release: 2014-11-03
ISBN: 008091456X
Category: Science
Language: EN, FR, DE, ES & NL

Encyclopedia of Ecology Book Excerpt:

The groundbreaking Encyclopedia of Ecology provides an authoritative and comprehensive coverage of the complete field of ecology, from general to applied. It includes over 500 detailed entries, structured to provide the user with complete coverage of the core knowledge, accessed as intuitively as possible, and heavily cross-referenced. Written by an international team of leading experts, this revolutionary encyclopedia will serve as a one-stop-shop to concise, stand-alone articles to be used as a point of entry for undergraduate students, or as a tool for active researchers looking for the latest information in the field. Entries cover a range of topics, including: Behavioral Ecology Ecological Processes Ecological Modeling Ecological Engineering Ecological Indicators Ecological Informatics Ecosystems Ecotoxicology Evolutionary Ecology General Ecology Global Ecology Human Ecology System Ecology The first reference work to cover all aspects of ecology, from basic to applied Over 500 concise, stand-alone articles are written by prominent leaders in the field Article text is supported by full-color photos, drawings, tables, and other visual material Fully indexed and cross referenced with detailed references for further study Writing level is suited to both the expert and non-expert Available electronically on ScienceDirect shortly upon publication

New Insights into Microbial Ecology through Subtle Nucleotide Variation

New Insights into Microbial Ecology through Subtle Nucleotide Variation
Author: A. Murat Eren,Mitchell Sogin,Loïs Maignien
Publsiher: Frontiers Media SA
Total Pages: 135
Release: 2016-10-26
ISBN: 2889199886
Category: Microbiology
Language: EN, FR, DE, ES & NL

New Insights into Microbial Ecology through Subtle Nucleotide Variation Book Excerpt:

The 16S ribosomal RNA gene commonly serves as a molecular marker for investigating microbial community composition and structure. Vast amounts of 16S rRNA amplicon data generated from environmental samples thanks to the recent advances in sequencing technologies allowed microbial ecologists to explore microbial community dynamics over temporal and spatial scales deeper than ever before. However, widely used methods for the analysis of bacterial communities generally ignore subtle nucleotide variations among high-throughput sequencing reads and often fail to resolve ecologically meaningful differences between closely related organisms in complex microbial datasets. Lack of proper partitioning of the sequencing data into relevant units often masks important ecological patterns. Our research topic contains articles that use oligotyping to demonstrate the importantance of high-resolution analyses of marker gene data, and providides further evidence why microbial ecologists should open the "black box" of OTUs identified through arbitrary sequence similarity thresholds.

The Ecology of Waste Water Treatment

The Ecology of Waste Water Treatment
Author: H. A. Hawkes
Publsiher: Elsevier
Total Pages: 214
Release: 2013-09-11
ISBN: 1483226026
Category: Technology & Engineering
Language: EN, FR, DE, ES & NL

The Ecology of Waste Water Treatment Book Excerpt:

The Ecology of Waste Water Treatment covers the principles of biology considered necessary for an understanding of some ecological aspects of wastewater treatment. This book is composed of seven chapters, and begins with an overview of the significant biological aspects related to wastewater treatment. The subsequent chapters examine the factors determining the dominant organisms in sludge and bacteria beds. Other chapters highlight the role of biological oxidation in wastewater treatment and the ecological parameters in the design and operation of activated sludge plants. A chapter provides practical methods of maintaining population balance at a low level of microorganisms. The final chapter considers the operational requirements necessary to ensure suitable ecological conditions for bacteria beds. This book is of value to microbiologists, ecologists, and environment-related fields.

Environmental Microbiology Fundamentals and Applications

Environmental Microbiology  Fundamentals and Applications
Author: Jean-Claude Bertrand,Pierre Caumette,Philippe Lebaron,Robert Matheron,Philippe Normand,Télesphore Sime-Ngando
Publsiher: Springer
Total Pages: 933
Release: 2015-01-26
ISBN: 940179118X
Category: Science
Language: EN, FR, DE, ES & NL

Environmental Microbiology Fundamentals and Applications Book Excerpt:

This book is a treatise on microbial ecology that covers traditional and cutting-edge issues in the ecology of microbes in the biosphere. It emphasizes on study tools, microbial taxonomy and the fundamentals of microbial activities and interactions within their communities and environment as well as on the related food web dynamics and biogeochemical cycling. The work exceeds the traditional domain of microbial ecology by revisiting the evolution of cellular prokaryotes and eukaryotes and stressing the general principles of ecology. The overview of the topics, authored by more than 80 specialists, is one of the broadest in the field of environmental microbiology. The overview of the topics, authored by more than 80 specialists, is one of the broadest in the field of environmental microbiology.

An Innovative Role of Biofiltration in Wastewater Treatment Plants WWTPs

An Innovative Role of Biofiltration in Wastewater Treatment Plants  WWTPs
Author: Maulin P. Shah,Susana Rodriguez-Couto,Jayanta Kumar Biswas
Publsiher: Elsevier
Total Pages: 526
Release: 2021-12-15
ISBN: 0128239476
Category: Science
Language: EN, FR, DE, ES & NL

An Innovative Role of Biofiltration in Wastewater Treatment Plants WWTPs Book Excerpt:

Many physico-chemical and operational factors influence the performance, treatment costs, and longterm stability of biofilters for the treatment of wastewater. An innovative role of biofiltration in wastewater treatment plants (WWTPs) focuses on identifying the factors that affect biofiltration, such as the hydraulic retention time of the biofiltration system, the type and characteristics of the filter, and the attached biomass, explains their influence and provides guidelines on how to control these factors to optimize better operation with respect to pollutant control present in (WWTPs). The fundamental basis of the treatment in biofilters is the action of pollutant-degrading microorganisms and consequently the book also discusses in depth about the microbial ecology of biofiltration. In addition, it explores the applications of biofiltration including the removal of emerging pollutants. Describes the microbial ecology of biofiltration Includes modeling of biofiltration Describes the designing of biofilters, start-up, and monitoring Discusses the mechanism of biofiltration Describes the controlling and operational factors of biofiltration

Environmental Protection Research Catalog Indexes

Environmental Protection Research Catalog  Indexes
Author: Smithsonian Science Information Exchange
Publsiher: Unknown
Total Pages: 135
Release: 1972
ISBN: 1928374650XXX
Category: Environmental protection
Language: EN, FR, DE, ES & NL

Environmental Protection Research Catalog Indexes Book Excerpt:

Microbial Ecology of Phototrophic Biofilms

Microbial Ecology of Phototrophic Biofilms
Author: Guus Roeselers
Publsiher: Guus Roeselers
Total Pages: 120
Release: 2007
ISBN: 9090221646
Category: Electronic Book
Language: EN, FR, DE, ES & NL

Microbial Ecology of Phototrophic Biofilms Book Excerpt:

Biofilms are layered structures of microbial cells and an extracellular matrix of polymeric substances, associated with surfaces and interfaces. Biofilms trap nutrients for growth of the enclosed microbial community and help prevent detachment of cells from surfaces in flowing systems. Phototrophic biofilms can best be defined as surface attached microbial communities mainly driven by light as the energy source with a photosynthesizing component clearly present. Eukaryotic algae and cyanobacteria generate energy and reduce carbon dioxide, providing organic substrates and oxygen. The photosynthetic activity fuels processes and conversions in the total biofilm community, including the heterotrophic fraction. This thesis starts with a brief introduction in the ecology of phototrophic biofilms and discusses their actual and potential applications in wastewater treatment, bioremediation, fish-feed production, biohydrogen production, and soil improvement and their role in biofouling. The next chapter describes the diversity of phototrophic bacteria in hot spring microbial mats found on the east coast of Greenland. In this study we utilized a polyphasic approach using a combination of isolation techniques, microscopic observation of morphological features, and cultivation-independent molecular methods. We observed a relationship between the cyanobacterial community composition and the in situ temperatures of different microbial mat parts. Chapter 4 focuses on the successional changes in community composition of freshwater phototrophic biofilms growing under different light intensities. Our results suggest that surface colonization by heterotrophic pioneers facilitates the development of phototrophic biofilms. In Chapter 5 we compared the community composition of phototrophic biofilms cultivated in three microcosm systems operated under identical conditions but placed in different laboratories. Denaturing Gradient Gel Electrophoresis (DGGE) analysis of both 16S and 18S rRNA gene fragments showed that the communities developed differently in terms of species richness and community composition. Chapter 6 demonstrates that nifD gene sequences, coding for a nitrogenase subunit, can be used to detect and identify diazotrophic cyanobacteria in natural communities. PCR products generated using primers homologous to conserved regions in the cyanobacterial nifD genes were subjected to DGGE and clone library analysis in order to determine the genetic diversity of diazotrophic cyanobacteria in environmental samples. In the last chapter we describe the development of PCR primers targeting conserved regions within the cyanobacterial hupS gene family. This gene is involved in the hydrogen metabolism of diazotrophic microorganisms. We analyzed hupS diversity and transcription in cultivated phototrophic biofilms by the direct retrieval and analysis of mRNA that was reverse transcribed, amplified with hupS specific primers, and cloned. Overall, the community composition and species richness of phototrophic biofilms was shown to be highly variable. Cultivation-independent molecular methods proved very useful to study diversity and function in phototrophic biofilms.