Effect of Acidithiobacillus thiooxidans Inoculation on the Chemical Properties of Saline Compost

Abstract Bacterial species of the genus Acidithiobacillus have been proved to reduce soil salinity, but their chemical impact on a saline compost has not been reported. This work is aimed to evaluate the effects of A. thiooxidans on the chemical properties of a saline compost formulation. When added to a microcosm under nonsterile conditions, a sulfur-supplemented A. thiooxidans inoculum lowered pH to 7.16, reduced exchangeable sodium levels to 97 cmol kg−1, and increased electrical conductivity to 7.93 dS m−1 after 720 h. No differences in bacterial fingerprint were observed after adding A. thiooxidans, either supplemented with sulfur or not. These results suggest that inoculating saline composts with sulfur-oxidizing bacterial strains of the genus Acidithiobacillus could help to decrease salinity-associated parameters, and it has the potential of reducing the impact of prolonged application of organic fertilizers on the soil. Additionally, it could be a valuable tool to remediate high-salinity soils.