Biogas, natural gas and other fuel gasses may contain corrosive components such as H2S which has detrimental effects on the environment when combusted. Consequently, it is required to remove H2S from gas before it can be used. Hence, a biotechnological desulfurization process was developed at Wageningen University, which uses natron-alkaline sulfide oxidizing bacteria (Fig. 1). This process is an alternative to chemo-physical processes which are commonly applied in industry. Advantages of the biological process are (i) no consumption of chelating chemicals, (ii) operation at atmospheric pressure and ambient temperature, (iii) high removal efficiency with a sulfide-free waste stream and (iv) beneficial use of the biologically produced sulfur.