Comparison of the capacity of biological desulfurization of Thiobacillus ferrooxidans from different sulfur-containing substrates with or without additional ferrous iron

Thiobacillus ferrooxidans, abbreviated as T. ferrooxidans is one of the important microorganisms in the field of biological desulfurization. Effects of ferrous iron and sulfur-containing substrates on biological desulfurization of T. ferrooxidans were studied. Results show that in the absence of Fe²⁺, T. ferrooxidans can utilize three kinds of sulfur-containing substrates of Na₂S₂O₃, elemental S and Na₂SO₃ for growth and metabolism. For utilization complexity, Na₂S₂O₃ was easiest to use, next was elemental S, and Na₂SO₃ was the worst for use. During the utilization of ferrous iron and sulfur-containing substrates by T. ferrooxidans, the iron oxidation system was first started. With the decrease of the Fe²⁺ concentration, the sulfur oxidation system was started, and then the two systems synergistically acted. The presence of three sulfur-containing substrates had different effects on Fe²⁺ oxidation, and elemental S did not inhibit the oxidation of Fe²⁺, while Na₂S₂O₃ and Na₂SO₃ had some inhibition on the oxidation of Fe²⁺, especially the inhibition of Na₂SO₃ was significant, and complete oxidation of ferrous iron needed more time. The isolated T. ferrooxidans is applied to the removal of H₂S gas, aiming to provide a new technological approach for biological removal of H₂S.