Mechanism and Kinetics of Elemental Sulfur Oxidation by Thiobacillus Thiooxidans in Batch Fermenter

Abstract

The sulfur oxidative capability of Thiobacillus thiooxidans (T.t.) has been investigated with respect to bioleaching capability for cadmium-contaminated soil. A preliminary mechanism was deduced in this study. The sulfur is simultaneously oxidized to thiosulfate and sulfite by action of T.t. The thiosulfate exibits growth inhibitory effect and consequently the pathway from sulfur to thiosulfate is considered to be strictly energy-production-associated while the pathway from sulfur to sulfite was found both energy-producing and growth-associated. Kinetic study analysis showed that the biomass production follows the Monod kinetic model with inhibition, whereas the sulfate production follows the same Monod model without inhibition.