Characterization of Multiple Heavy Metal Resistant Bacillus cereus IEI-01 Isolated from Industrial Effluent and its In Vitro Bioremediation Potential

Heavy metal (HM) pollution has been a significant issue for the environment and public health. Unmonitored industrial effluents are a major source of HM pollution. However, metallotolerant bacteria thriving in such environments could be potentially useful for bioremediation purposes. In this study, Bacillus cereus IEI-01 was isolated from water samples of Badshahpur Lake, Gurugram, showcasing resilience to HM exposure and thriving under optimal conditions at 37°C and pH 7.0. Morphological and biochemical characterization showed its Gram-positive rod shape and metabolic versatility, including glucose fermentation and nitrate reduction capabilities. Molecular analysis further affirmed its close relation to the Bacillus cereus strain. Dynamic bacterial growth patterns were observed, with typical sigmoidal curves indicating significant growth over 72 h. When exposed to various HMs, the strain IEI-01 exhibited differential tolerance and promoting patterns, with cadmium (Cd) and lead (Pb) compared to other metals. Over 72 h, the strain exhibited substantial removal rates ranging from 60.64% to 87.43% for Cd and 41.87% to 52.62% for Pb. The concentration-dependent bio-removal efficiency of IEI-01 in Cd-spiked cultures displayed a declining trend with increasing concentrations, with removal rates ranging from 80.23% to 60.72% over the same period. These findings highlight the potential of Bacillus cereus IEI-01 for HM bioremediation, particularly at lower concentrations. Its efficacy in removing Cd and Pb from contaminated environments suggests promising applications in environmental cleanup efforts.