This book provides a comprehensive and detailed source of information on the genetic and regulatory aspects of biological nitrogen fixation in free-living (non-symbiotic) prokaryotes. Biological nitrogen fixation is represented in a diverse range of microorganisms, among which Klebsiella pneumoniae serves as a paradigm for the genetic analysis of diazotrophy, which is the ability to grow with N2 as sole nitrogen source. The volume uses two major complementary approaches to the subject matter. The initial chapters use an organismic-based approach by concentrating on the well-characterized diazotrophic proteobacteria, cyanobacteria, Gram-positive clostridia, and Archea. The later chapters use a comparative process-based approach and serve as overviews dealing with different regulatory aspects, electron transport to nitrogenase, and molybdenum metabolism, across the range of organisms. Whenever appropriate, historical aspects and agricultural and ecological impacts have been taken into consideration. Each chapter contains an extensive list of references. This book is the self-contained second volume of a comprehensive seven-volume series. No other available work provides the up-to-date and in-depth coverage of this series and this volume. This book is intended to serve as an indispensable reference work for all scientists working in this and closely related fields, to assist students to enter this challenging area of research, and to provide science administrators easy access to vital relevant information.

Genetics and Regulation of Nitrogen-Fixing Bacteria This book is the second volume of a seven-volume series, which covers all fields of research related to nitrogen fixation - from basic studies through applied aspects to environmental impacts. Volume II provides a comprehensive and detailed source of information concerning the genetics and regulation of biological nitrogen fixation in free-living prokaryotes. This preface attempts to provide the reader with some insight into how this volume originated, how it was planned, and then how it developed over the several years of its production. Once the editorial team was established, the first job was to decide which of the many free-living diazotrophs that have been subjected to genetic analysis should be included in this volume. Would we need to develop specific criteria for selection or would the organisms, in effect, select themselves? Of course, Klebsiella pneumoniae and Azotobacter vinelandii, which have served (and still serve) as the main model organisms for the genetic analysis of diazotrophy, plus some of the other bacteria described in this volume, did indeed select themselves. However, there was considerable discussion surrounding well-characterized fixing species, like Azorhizobium caulinodans and Herbaspirillum seropedicae, both of which are able to fix atmospheric N under free-living conditions.