Sulfur (S) deficiency in soils is becoming increasingly common in many areas
of the world as a result of agronomic practices, high biomass exportation and
reduced S emissions to the atmosphere. In this review, the incidence and
commercial exploitation of S pools in nature are discussed, as well as the importance
of S for plants and the organic and inorganic S forms in soil and their
transformations, especially the process of microbiological oxidation of elemental
sulfur (S0) as an alternative to the replenishment of S levels in the soil. The diversity
of S0-oxidizing microorganisms in soils, in particular the genus Thiobacillus, and
the biochemical mechanisms of S0 oxidation in bacteria were also addressed.
Finally, the main methods to measure the S0 oxidation rate in soils and the variables
that influence this process were revised.
Index terms: fertilization, agriculture, microbial diversity, soil fertilit