Toxicity of Commercial Surfactants to Phosphate-Accumulating Bacterium

The toxicity of twelve commercial surfactants to phosphate-accumulating bacterium Acinetobacter junii was tested. The tested products were selected to cover a variety of surfactant types and classes (anionic, cationic, amphoteric and nonionic). One surfactant proved to be highly toxic (EC50 < 1 mg L–1), six surfactants were toxic (EC50 values between 1 and 10 mg L–1), two were harmful (EC50 values between 10 mg L–1 and 100 mg L–1) and three surfactants with EC50 higher than 100 mg L–1 were considered as non-toxic to A. junii. The most toxic commercial surfactant was Kutriacid (linear alkylbenzene sulphonate) with EC50 value of 0.15 mg L–1. When all of the tested surfactants were compared there could be no generalization in toxicity regarding the class or the length of the alkyl chain of surfactant. One observed feature is that all of the surfactants with branched alkyl chain had least toxic or no toxic effect to A. junii.