THE PRODUCTION OF HYDROGEN SULPHIDE BY BACTERIA

Abstract

Hydrogen sulphide formation in sewage is supposed to be due to two distinct processes, the splitting of protein by certain organisms and the reduction of inorganic sulphates by others. Led-erer (1913) concludes that more hydrogen sulphide is formed under 'anaerobic than under aerobic conditions. He thinks that the formation of hydrogen sulphide from protein is a selective process and that it depends a great deal on the position of the sulphur radical in the protein molecule. At any rate other factors than reduction are involved in hydrogen sulphide formation. An organism may be a very strong nitrate reducer and at the same time a weak hydrogen sulphide former, although both reactions are reducing processes. Lederer is of the opinion that the reduction of inorganic sulphates may however be an important factor in hydrogen sulphide formation, and thinks it probable that the action may be due to some unknown specific organism similar to the Spirillum desulphuricans of Beijerinck (1895). Several workers have observed the formation of hydrogen sul-phide in large quantities in the effluent of sewage disposal plants. Barr and Buchanan (1912) report the isolation of a specific organism in one such instance. Clark (1913) and others have reported the reduction of inorganic sulphates in sewages. Sulphur metabolism may also play a beneficial r6le in sewage disposal in that certain species of bacteria may cause the oxidation of sulphur and of hydrogen sulphide to sulphates thus reducing the amount of odor. This is a well known property of such organisms as Beggiatoa and Thiothrix (Jordan, 1918).