Bacterial Tolerance and Reduction of Chromium (VI) by <i>Bacillus cereus</i> Isolate PGBw4

Abstract

This study aimed to determine the bacterial tolerance to chromium (Cr⁶⁺) in three growth media, such as nutrient broth, Luria Bertani (LB) broth and mineral salt media in terms of Minimum Inhibitory Concentration (MICs). Among the seven metal resistant soil bacteria, <i>Bacillus cereus</i> isolate PGBw4 and <i>Bacillus cereus</i> strain ES-4a1showed highest tolerance against Cr⁶⁺ in all three media. <i>Bacillus cereus</i> isolate PGBw4 was used as an effective and environment friendly agent for detoxifying Cr(VI) and reduction study in this research. The bacterial isolate mitigated toxic effects of Cr(VI) more efficiently from 100mg/L to 500mg/L within 24 and 48 hours respectively. The maximum amount of reduction of Chromium (VI) was 70.67 percent at 100 of Cr(VI) mg/L concentration after 48 hours of incubation and the lowest was 42 percent at 500mg/L Chromium concentration after 24 hours of incubation.