Nannochloropsis

Nannochloropsis is a genus of algae comprising 6 known species. The genus in the current taxonomic classification was first termed by Hibberd (1981). The species have mostly been known from the marine environment but also occur in fresh and brackish water. All of the species are small, nonmotile spheres which do not express any distinct morphological feature, and cannot be distinguished by either light or electron microscopy. The characterisation is mostly done by rbcL gene and 18S rRNA sequence analysis. The algae of the genus Nannochloropsis differ from other related microalgae in that they have chlorophyll a and completely lack chlorophyll b and chlorophyll c. In addition they are able to build up a high concentrations of a range of pigments such as astaxanthin, zeaxanthin and canthaxanthin. They have a diameter of about 2 to 3 micrometers and a very simple ultrastructure with reduced structural elements compared to neighbouring taxa. Nannochloropsis is considered a promising alga for industrial applications because of its ability to accumulate high levels of polyunsaturated fatty acids. Moreover, it shows promising features that can allow genetic manipulation aimed at the genetic improvement of the current oleaginous strains. Various species of Nannochloropsis indeed are transfectable and there has been evidence that some strains are able to perform homologous recombination.At the moment it is mainly used as an energy-rich food source for fish larvae and rotifers. Nevertheless, it has raised growing interest also for the investigation of biofuel production from photosynthetic organisms. (see Nannochloropsis and biofuels). Nannochloropsis is actually in use as food additive for human nutrition and it is also served at Restaurant 'A Poniente' of El Puerto de Santa María (Cádiz, Spain) close to the natural environment where Nannochloropsis gaditana was first isolated and still grows.