Sulphate reduction and biomass growth rates for Desulfobacterium autotrophicum in yeast extract – Supplemented media at 38°C

Water pollution by heavy metals and sulphates is common in areas with mineral deposits. Sulphate-reducing bacteria (SRB) are microorganisms widely distributed, and can be used as heavy metals removal agents. Furthermore, the use of organic substrates or wastes in SRB systems could reduce the cost and increase the treatment efficiency. The aim of the study was to assess the sulphate reduction capacity and growth rates of the bacterium Desulfobacterium autotrophicumin batch culture media supplemented with different concentrations of yeast extract. At 38°C, in the growth phase, there was a direct relationship between the concentration of yeast extract employed and the biomass growth and sulphate reduction rates. In the presence of low sulphide concentrations, supplementary 0.5 g/L of yeast extract maximized sulphate reduction on a per-cell basis, but at high concentrations of H2S it would be advisable to use 2 g/L to reduce the product inhibition.