A novel method for the measurement of elemental selenium produced by bacterial reduction of selenite

The measurement of elemental selenium (Se0) is needed to assess the rate and magnitude of bacteria reduction of selenite or selenate. We have developed a spectrophotometric method for the measurement Se0 that is rapid and can be employed to measure the quantity of Se0 produced by bacterial cultures. This method employs the use of 1 M Na2S to convert the insoluble elemental selenium to a red-brown solution and with this method there is a direct correlation between concentration of elemental selenium and the absorption at 500 nm. To demonstrate the utility of this assay, we have followed the reduction of selenite to Se0 by Moraxella bovis, and by bacterial consortia in soil and water samples.