Potential of Thiobacillus ferrooxidans for waste gas purification. Pt. 1

Kinetic data of ferrous iron oxidation by Thiobacillus ferrooxidans were determined. The aim was to remove H2S (< 0.5 ppm) from waste gas by a process proposed earlier. Kinetic data necessary for industrial scale-up were investigated in a chemostat air-lift reactor (dilution rate 0.02-0.12 h-1; pH 1.3). Due to the low pH, ferric iron precipitation and wall growth could be avoided. The maximum ferrous iron oxidation rate of submersed bacteria was 0.77 g l-1 h-1, the maximum specific growth rate about 0.12 h-1 and the yield coefficient was found to be 0.007 g g-1 Fe2+. The specific O2 demand of an exponentially growing, iron-oxidizing batch culture was 1.33 mg O2 mg-1 biomass h-1. The results indicate that a pH of 1.3 has no negative influence on the kinetics of iron oxidation and growth. (orig.)