Metabolic response of tellurite resistant Bacillus altitudinis strain 3W19 highlights the potential as a model organism for bioremediation

Contaminated environments can pose new challenges when new contaminants appear and can select organisms with new genetic and metabolic strategies. The increased presence of Te(IV) in the environment is becoming more important. This highlights how underexplored the investigation of how bacteria molecularly respond to less common environmental contaminants, such as tellurite when compared to other metals/ metalloids. Understanding what tools an organism uses from its genetic pool when responding to a new contaminant requires a multiple-technique approach, such as metabolic tests and differential omics analysis. These analyses provide a full metabolic and phenotypical map of stress response that can include new resistance mechanisms, whether specific or not. This study aimed to determine if Bacillus altitudinis strain 3W19, isolated from a Te(IV) contaminated site, presents specific changes at the proteomic level when exposed to the metalloid. In strain 3W19, growth in the presence of Te(IV) upregulated pathways of amino acid metabolism and membrane transport and downregulated pathways of carbohydrate metabolism. Growth in the presence of Te(IV) also induced the formation of reactive oxygen species and lowered the metabolic activity of the strain. This metal led to the overexpression of the proteins of the ter gene cluster. When compared with other strains, the ter system identified in this strain differed in genomic organization from related Bacillus sp. strains. Together, these strain-specificities can contribute to understanding its Te(IV) resistance phenotype.