Cyanobacteria were the first organisms capable of oxygenic photosynthesis on Earth. Due to this trait and their wide distribution in freshwater and marine waters, they are important primary producers in aquatic environments. Some cyanobacteria are capable of atmospheric nitrogen gas (N2) fixation, allowing them to sustain growth under nitrogen-limiting conditions. This chapter provides an introduction to the physiology and genetics underpinning N2 fixation, the different modes of N2 fixation realized in different orders, and the phylogeny of nif genes, which encode components of the nitrogenase complex. We provide a brief overview of freshwater species and the important marine cyanobacterium Trichodesmium, then focus on the biological applications of N2-fixing cyanobacteria for wastewater metal remediation, biofertilizers, bioenergy production (e.g., hydrogen gas, which is a byproduct of N2 fixation), and other high-value products (e.g., pigments such as phycocyanin and phycoerythrin as antioxidants, exopolysaccharide-derived cosmetics, ultraviolet sunscreens).
|Title of host publication||Handbook of Marine Microalgae: Biotechnology Advances|
|Subtitle of host publication||Biotechnology Advances|
|Number of pages||15|
|Publication status||Published - 2015|