Abstract
The anaerobic oxidation of dissolved H2S into elemental sulfur was studied at 23°C and pH 6.5±0.3 in a continuous culture of the phototrophic green sulfur bacterium Chlorobium limicola. The number of free cells formed in the culture was proportional to the amounts of H2S oxidized, and the growth yield was independent of light intensity. The specific growth rate was significantly dependent on the dissolved H2S concentration (0.03-3.16mol·m-3) and light intensity (200-16000 1x), and the kinetic data were analyzed with a rate expressed as a function of each rate-limiting factor. Under illumination by white fluorescent lamps, the specific oxidation rate of C. limicola reached a maximum of 2.08×10-14 molh-1·cell-1 when the dissolved H2S concentration was 2.29 mol·m-3 at 5000 lx. The phototrophic H2S oxidation rates per unit reactor volume were quantitatively simulated as a function of the number of equal-size reactors placed in series, by using the rate expression and estimated growth parameter values.
