Abstract:
Cyanobacteria exist under a variety of climatic, nutrient and physical
conditions, and are likely to form blooms. This distinct group of bacteria is
photosynthetic and produce several metabolites that include a number of
endotoxins, of which are commonly found in mass occurrences of cyanobacteria,
especially under eutrophic conditions. Microcystins (MCs) are well-studied
cyanobacterial cyclic hepatopeptide heapatotoxins predominantly produced by
freshwater cyanobacteria, including species of Microcystis, Anabaena, Nostoc
and Planktothrix. Potential chronic toxicity from MC led the WHO to establish
a guideline value of 1 μg l–1 as a maximum concentration of MC-LR in drinking
water. Additional concern regarding the importance of cyanotoxins, is reflected
by their inclusion in the US Environmental Protection Agency (USEPA)
drinking water contaminant list and in major reviews along with chemical
warfare agents. Furthermore, MC-LR was classified as a possible human
carcinogen (group 2B). However, only very less data on the occurrence of
microbial degradation of MC are available in the world.
