Hydrogen sulfide (H_2 S) is a toxic and environmentally harmful component present in many different gas streams. Removal of this substance using bacteria offers many advantages over traditional physicochemical methods, but some aspects of how bacteria remove H_2 S are not yet fully understood. This project will use mathematical modelling to further investigate the functioning of these bacteria, and to predict optimal conditions for bacteria to improve stability, economic feasibility and environmental sustainability of the biological desulfurisation process.