Abstract

A water-soluble anion containing selenium, selenocyanate (SeCN-), is produced in various industrial settings including petrochemical refining and mining wastewaters and is difficult to remove using common chemical or physical processes. The work described was aimed at determining the relative acute toxicity of SeCNby evaluating its minimal inhibitory and minimal bactericidal concentrations for 1) a bacterium (LHVE) that produces volatile selenium-containing derivatives in cultures containing added SeCNand 2) for a sensitive E. coli wild-type strain. These measures of toxicity were compared to those of selenate and selenite, the oxyanions of selenium commonly found in the environment. Cultures of LHVE amended with SeCNon agar plates produced red, elemental selenium after three days. As far as we know this is the first evidence for the biological production of elemental Se by a metalloid-resistant bacterium exposed to selenocyanate. Bioprocessing of selenite and SeCNby both types of bacteria, as analyzed by inductively coupled plasma spectrometry, demonstrated that LHVE more successfully incorporates or precipitates Se compared to E. coli.