Biotoxicity of mercury to Chlorella vulgaris as influenced by amino acids.

The toxicity of mercury ion, on Chlorella vulgaris, is largely influenced by amino acids. Five amino acids, namely alanine, asparagine, glutamic acid, cysteine and histidine, were added separately to the medium containing static dose of mercury. Survival (%) of the alga was reduced with the increasing concentrations of mercury. Of these five amino acids, cysteine was found to be the most effective while alanine and glutamic acid were the least effective on reducing the toxic effect of mercury on the alga measured in terms of growth, chlorophyll and protein content. The order of detoxification was Alanine < Glutamate < Asparargine < Histidine < Cysteine. Amino acids from ligands with Hg2+ making it less toxic to the alga and produce an additional source of energy for growth and development.