Hydrogen production by cyanobacteria

Abstract

The cyanobacteria, formerly known as blue-green algae, are a diverse group of prokaryotes capable of carrying out oxygenic photosynthesis. They are a monophyletic group of Gram-negative bacteria consisting of both freshwater and marine species and grow and prosper in a wide variety of habitats; oceans, rivers and lakes, deserts, and Antarctic ice as well as forming a number of symbioses with different plants and fungi. Cyanobacteria can be either unicellular or filamentous (heterocystous and nonheterocystous), and are present as cells of varying sizes and a broad spectrum of morphologies. Diversity is also seen in the sizes of their genomes, with sequenced genomes ranging from 1.66 (Prochlorococcus marinus) to 9.2 Mbp (Nostoc punctiforme). These organisms continue to serve as models for the study of basic biological process, in particular photosynthesis and, since some filamentous species can differentiate various cell types, heterocysts, akinetes and hormogonia, cellular development, and intracellular communication. Nutritional requirements are minimal and are easily met by simple salt solutions, which might be provided by the dilution of various waste streams.