Nannochloropsis

Nannochloropsis
Nannochloropsis viewed under a light microscope
Scientific classification Edit this classification
Domain: Eukaryota
Clade: Diaphoretickes
Clade: SAR
Clade: Stramenopiles
Phylum: Gyrista
Subphylum: Ochrophytina
Class: Eustigmatophyceae
Order: Eustigmatales
Family: Monodopsidaceae
Genus: Nannochloropsis
D.J.Hibberd, 1981[1]
Type species
Nannochloropsis oculata
(Droop 1955) Hibberd 1981

Nannochloropsis is a genus of algae comprising six known species. The genus in the current taxonomic classification was first termed by Hibberd (1981).[2] The species have mostly been known from the marine environment but also occur in fresh and brackish water.[3] All of the species are small, nonmotile spheres which do not express any distinct morphological features that can be distinguished by either light or electron microscopy. The characterisation is mostly done by rbcL gene and 18S rRNA sequence analysis.[4]

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.[5] They have a diameter of about 2 to 3 micrometers[6] 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.[7][8] 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.[9] 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.[10] A 2020 study suggests it could be used for a highly performant, sustainable fish-free feed for farmed fish.[11][12]

  1. ^ Hibberd, D. J. (1981). "Notes on the taxonomy and nomenclature of the algal classes Eustigmatophyceae and Tribophyceae (synonym Xanthophyceae)". Botanical Journal of the Linnean Society. 82 (2): 93–119. doi:10.1111/j.1095-8339.1981.tb00954.x.
  2. ^ Hibberd (1981). "Notes on the taxonomy and nomenclature of the algal classes Eustigmatophyceae and Tribophyceae (Synonym Xanthophyceae)". Botanical Journal of the Linnean Society. 82 (2): 93–119. doi:10.1111/j.1095-8339.1981.tb00954.x.
  3. ^ Fawley (2007). "Observations on the Diversity and Ecology of Freshwater Nannochloropsis (Eustigmatophyceae), with Descriptions of New Taxa". Protist. 158 (3): 325–336. doi:10.1016/j.protis.2007.03.003. PMID 17576099.
  4. ^ Andersen, R. A.; Brett, R. W.; et al. (1998). "Phylogeny of the Eustigmatophyceae based upon 18s rDNA, with emphasis on Nannochloropsis". Protist. 149 (1): 61–74. doi:10.1016/S1434-4610(98)70010-0. PMID 23196114.
  5. ^ Lubian, L. M.; et al. (2000). "Nannochloropsis (Eustigmatophyceae) as source of commercially valuable pigments". Journal of Applied Phycology. 12 (3/5): 249–255. doi:10.1023/A:1008170915932. S2CID 620002.
  6. ^ Kandilian, R.; Lee, E.; Pilon, L. (2013). "Radiation and optical properties of Nannochloropsis oculata grown under different irradiances and spectra". Bioresource Technology. 137: 63–73. doi:10.1016/j.biortech.2013.03.058. PMID 23587810.
  7. ^ Assaf Sukenik, Y. C. T. B. (1989). "Regulation of fatty acid composition by irradiance level in the Eustigmatophyte Nannochloropsis sp". Journal of Phycology. 25 (4): 686–692. doi:10.1111/j.0022-3646.1989.00686.x. S2CID 84590502.
  8. ^ Boussiba, S.; Vonshak, A.; Cohen, Z.; Avissar, Y.; Richmond, A. (1987). "Lipid and biomass production by the halotolerant microalga Nannochloropsis salina". Biomass. 12: 37–47. doi:10.1016/0144-4565(87)90006-0.
  9. ^ Kilian, O.; Benemann, C. S. E.; Niyogi, K. K.; Vick, B. (2011). "High-efficiency homologous recombination in the oil-producing alga Nannochloropsis sp". Proc. Natl. Acad. Sci. U.S.A. 108 (52): 21265–21269. doi:10.1073/pnas.1105861108. PMC 3248512. PMID 22123974.
  10. ^ Lubian, L. M. (1982). "Nannochloropsis gaditana sp. nov., a new Eustigmatophyceae marina strain". Lazaroa. 4: 287–293.
  11. ^ "Research breakthrough achieves fish-free aquaculture feed that raises key standards". phys.org. Retrieved 9 December 2020.
  12. ^ Sarker, Pallab K.; Kapuscinski, Anne R.; McKuin, Brandi; Fitzgerald, Devin S.; Nash, Hannah M.; Greenwood, Connor (12 November 2020). "Microalgae-blend tilapia feed eliminates fishmeal and fish oil, improves growth, and is cost viable". Scientific Reports. 10 (1): 19328. Bibcode:2020NatSR..1019328S. doi:10.1038/s41598-020-75289-x. ISSN 2045-2322. PMC 7665073. PMID 33184333. Available under CC BY 4.0.