Assessment Of Selenite And Chromate Reduction Potential In Bacillus safensis And Bacillus altitudinis Isolated From Industrial Sites

Abstract

This study investigates the selenite- and chromate-reducing capabilities of Bacillus safensis and Bacillus altitudinis strains isolated from industrially contaminated soil. These heavy metals pose significant threats to human health and ecosystems. The strains of B. safensis and B. altitudinis were isolated, purified and subjected to a series of biochemical tests and analytical strategies, including bacterial growth assays and spectrophotometric methods to determine the reduction potential of these strains. The results clearly emphasized the natural abilities of these strains to reduce selenite and chromate efficiently. Notably, B. safensis strains S1 and S9 reduced selenite by 46% and 53%, respectively, while B. altitudinis strain S2 achieved a 69.5% reduction. Physiological parameters such as temperature, pH, salinity, and metal ion concentration were optimized to enhance reduction efficiency. Optimal conditions were identified at 37°C and pH 9, under which the highest reduction rates were observed; the lowest reductions occurred at 25°C and pH 5. Taxonomic identification was performed using 16S rRNA gene sequencing, and a phylogenetic tree was constructed to confirm species classification. The findings support the potential use of B. safensis and B. altitudinis in bioremediation, specifically for detoxifying selenium and other heavy metals in polluted environments.