Production of hydrogen sulfide by a moderately thermophilic iron-oxidizing bacterium strain TI-1

Abstract

A moderately thermophilic iron-oxidizing bacterium strain TI-1 has been shown to have a unique enzyme system that produces hydrogen sulfide (H 2S) extracellularly under acidic conditions. The optimal culture conditions for H 2S production were determined to apply the bacterium to the treatment of acidic wastewater containing heavy metals. The production of H 2S by the cells was dependent on l-glutamic acid, ferrous sulfate and elemental sulfur in the medium. The optimal culture medium for H 2S production contained 0.3% l-glutamic acid, 1.7% ferrous sulfate, and 1.0% elemental sulfur and the optimal pH and temperature were 4.0 and 55°C, respectively. Under the optimal culture conditions, strain TI-1 produced H 2S continuously at a rate of 0.2 μmol/ml/d for 14 d.