African Journal of Biotechnology Vol. 3 (3), pp. 159-168, March 2004

Review

Microcystis aeruginosa: source of toxic microcystins in drinking water

Oberholster PJ¹, Botha A-M²* and Grobbelaar JU¹

¹Department of Plant Sciences, Faculty of Natural and Agricultural Sciences, University of the Free State, PO Box 339, Bloemfontein, ZA9300

²Department of Genetics, Forestry and Agriculture Biotechnology Institute, University of Pretoria, Hillcrest, Pretoria, ZA0002, South Africa

*Corresponding author: Email: AMBothao@postino.up.ac.za. Phone: +27 (12) 420 3945. Fax: +27 (12) 420 3947.

Accepted 21 December 2003

Cyanobacteria are one of the earth’s most ancient life forms. Evidence of their existence on earth, derived from fossil records, encompasses a period of some 3.5 billion years in the late Precambrian era.  Cyanobacteria are the dominant phytoplanton group in eutrophic freshwater bodies worldwide. They have caused animal poisoning in many parts of the world and may present risks to human health through drinking and recreational activity.  Cyanobacteria produce two main groups of toxin namely neurotoxins and peptide hepatotoxins. They were first characterized from the unicellular species, Microcystis aeruginosa, which is the most common toxic cyanobacterium in eutrophic freshwater.  The association of environmental parameters with cyanobacterial blooms and the toxicity of microcystin are discussed. Also, the synthesis of the microcystins, as well as the mode of action, control and analysis methods for quantitation of the toxin is reviewed.

Key words: Cyanobacteria, microcystins, mcyB gene, PCR-RFLP.