Fate of substituted benzoates in the freshwater green alga, Chlamydomonas reinhardtii 11-32b

The removal of chlorinated, nitrated, and sulfonated benzoic acids in cultures of the unicellular green alga, Chlamydomonas reinhardtii 11-32b, was investigated, and the metabolic fate of a model compound, 4-chloro-3,5,-dinitrobenzoic acid, was determined. The freshwater alga was able to remove a wide variety of benzoic compounds from the incubation medium. Chlamydomonas discriminated very specifically between the benzoic acids, indicated by the varying degrees of which the test compounds disappeared from the culture medium. Moreover, the alga was capable of transforming 4-chloro-3,5-dinitrobenzoic acid to several metabolites. A release of chloride ions was ob served, and 3,5-dinitro-4-hydroxybenzoic acid was identified as a major transient pro duct in the algal metabolism of 4-chloro-3,5-dinitrobenzoic acid.