Biocatalytic Hydrogen Sulphide Removal from Gaseous Streams

Abstract

Hydrogen sulphide is one of the most important substances responsible for unpleasant odour emissions in gas phase. It is often formed in higher concentration beyond other sulphur containing volatile compounds like methane thiol (MT), dimethyl sulphide (DMS) and dimethyl disulphide (DMDS). Removal of hydrogen sulphide is usually carried out by physical-chemical methods (e.g. adsorption), but nowadays some bio-processes may be considered as promising alternatives. Certain sulphur oxidising thiobacteria can be successfully applied for hydrogen sulphide conversion from gaseous streams like biogas. Various strains have been applied so far for degradation of hydrogen sulphide, they belong mostly to the group of Thiobacillus, which are autotrophic microorganisms. These autotrophic bacteria have the drawback in application that they grow slower than the heterotrophic ones and it is more difficult to control their growth. A number of chemotrophs are suitable for the biodegradation of H2S. These bacteria grow and produce new cell material by using inorganic carbon (CO2) as a carbon source and chemical energy from the oxidation of reduced inorganic compounds such as H2S.The objective of the work described here was to study the ability of elimination of hydrogen sulphide by two chemotrophic microorganisms (Thiomonas intermedia, Thiobacillus thioparus) in a batch bioreactor. The other aim was the study of the immobilization of these bacteria to different supports.