A heterotrophic Pseudomonas putida CH11 was isolated from livestock farming wastewater and applied for the treatment of H 2 S-containing gas. Extensive tests including removal characteristics, metabolic products, and removal efficiencies of H 2 S by P. putida CH11 were examined in batch and continuous systems. The optimum pH required to remove hydrogen sulfide was found in the range of 6-8. The maximum removal rate and the saturation constant were calculated to be V(m) = 1.36 g S/day·kg dry bead and K(s) = 45.9 ppm, respectively. The main metabolic product of H 2 S oxidation was determined to be elemental sulfur. When P. putida CH11 was immobilized within Ca alginate, the cells exhibited high H 2 S removal efficiency, in excess of 96%, at concentrations of hydrogen sulfide from 10 to 150 ppm (flow rates of 36 and 72 L/h). These results suggest that P. putida CH11 immobilized within Ca alginate has the potential to be used as a H 2 S removal agent.