Genetic variability in Acidithiobacillus spp. – a working horse of environmental biotechnologies

Abstract

The genus Acidithiobacillus comprises 7 species of Gram-negative obligatory acidophilic chemolithotrophic bacteria that derive energy mainly from the oxidation of reduced sulphur compounds. Four of the species also catalyse the dissimilatory oxidation of ferrous iron while three (A. thiooxidans, A. albertensis, and A. caldus) do not. Bacteria from the genus Acidithiobacillus are often associated with mineral biotechnologies (biomining) and acid mine drainage. While acceleration of mineral solubilisation is a positive aspect in environmental biotechnologies, it is undesirable in acid mine drainage with strong negative ecological impact and there is profound interest in genetics and genomics of these bacteria. Representatives of Acidithiobacillus genus occur world-wide, however there are limited data on Acidithiobacillus spp. variability from Slovakia. In our work the variability of Acidithiobacillus spp., from Slovakia was analysed and the presence of A ferrooxidans was detected. In addition, for the first time we report here on the occurrence of A. albertensis as well. Comparative analyses confirmed pronounced genetic and genomic diversity within the genus, especially within A. ferrooxidans and A. thioxidans complexes. Based on data presented, several Acidithiobacillus species could be considered as a complex species and the description of several new species is very probable in the near future.