Unlocking nature’s clean-up crew: marine Bacillus species as agents of heavy metal detoxification

Heavy metal pollution is a formidable global environmental concern, with far-reaching consequences for ecosystems and grave health risks to humans and wildlife. This study investigated the potential of extremophilic Bacillus Sp : strains, namely Bacillus halotolerans , as bioresources for addressing heavy metal contamination through bioremediation. These Bacillus species exhibited remarkable resistance and biodegradation capabilities toward toxic heavy metals through rigorous lab-scale fermentation experiments. Within 24–48 h, Bacillus strains demonstrated the ability to reduce concentrations of Hg 2+ , Pb 2+ , and Cr 6+ by 100–1700 mg/L, transforming them into less toxic forms was analysed by atomic absorption spectroscopy (AAS). This transformative process may be attributed to the secretion of extracellular enzymes responsible for the bio-reduction of heavy metals. Furthermore, our research revealed that the identified Bacillus isolate exhibited high levels of tolerance to multiple heavy metals, including mercury (100–700 ppb), lead (100–1500 ppm), and chromium (100–1500 ppm). The utilization of electron micrographs confirmed the adsorption of metals, leading to the intracellular accumulation of Hg 2+ , Pb 2+ , and Cr 6+ with bioaccumulated heavy metal ions depositing around the cell envelope of Bacillus species. As we know, it is crucial to note the need for effective and sustainable methods for the bioremediation of heavy metals. Marine Bacillus sp.‘s unique characteristics and capabilities have made them promising bioresources for bioremediation in recent years. These findings showcase the resilience of marine Bacillus sp . in surviving heavy metal toxicity present in soil and wastewater, making them a promising bioresource for the remediation of heavy metal-contaminated soil and wastewater.