Abstract: The invention provides novel strains Agrobacterium tumefaciens KKP 2039p and Paracoccus alcaliphilus KKP 2040p, the plasmid pSinA and its functional derivative, method for producing bacterial strains capable of chemolithotrophic arsenite oxidation and novel bacterial strains produced by this method. The invention also relates to the composition, comprising the novel bacterial strain or the plasmid pSinA and the use of these novel strains, as well as the method of bioaugmentation of an arsenic contaminated environment, particularly the method for the removal of arsenic from waters.