Selenite detoxification by Bacillus spp isolated from indigenous polluted sites

Abstract

This investigation was proposed to monitor the ability of isolated Bacillus spp. to transform toxic forms of selenium (selenium oxyanions) to non toxic selenium. These strains reduced up to 89% selenite on average at 37ºC after time of incubation. At higher initial concentrations (100, 200, 400, 600 and 800 µg ml^-1), reduction value dropped to 31%. In the presence of other metals stresses (Co, Hg and Cr at a concentration of), the average selenite reduction percentage was 48%. This reduction value shifts from 87% to 94% with the increase in incubation time (from hrs to hrs). Reduction potential of these strains decreased 81% to 27% at various initial selenium concentrations in N-broth and acetate minimal media, respectively. With the increase in the sodium concentration of the media, the measured selenite reduction was above 95%. After exposure to the UV treatment B. pichinoty lost its ability to reduce selenite while B. endophyticus and B. foraminis reduced up to 96% and 71%, of selenite, respectively.

Keywords: Selenite, bacteria, Bacillus, Bioremediation, heavy metals