The fixed-film bioscrubber was developed for hydrogen sulfide removal. Acinetobacter sp. MU1_03 and Alcaligenes faecalis MU2_03 are two new strains of microorganisms from the fixed-film bioscrubber systems found. Under certain conditions, they exhibited more than 91% of hydrogen sulfide removal efficiency while a mixture of the two strains was capable of 98% hydrogen sulfide removal. Removal efficiency increased with decreasing inlet gas flow rates, increasing the height of packing and empty bed retention time. During the operation, the pH decreased but did not fall below 6.4. Sulfate production increased when the removal efficiency increased due to the oxidation of hydrogen sulfide to sulfate. In addition, dissolved oxygen decreased during the same reaction. (c) 2005 Elsevier Ltd. All rights reserved.