The Isolation and Identification of Novel Arsenic-Resistant Bacteria from an Arsenic-Contaminated Region—A Study to Understand the Efficiency of Bacteria for Arsenic Removal from Aqueous Media

Drinking water sources with groundwater arsenic (As) contamination face multifaceted
challenges in the removal and supply of fresh drinking water resources. To eradicate this problem,
bioremediation has evolved to become more effective than other chemical and physical removal
processes in its cost-effectiveness, high removal efficiency, and lesser production of secondary byproducts
or waste. Thus, this study aimed to treat As from aqueous media and to detoxify highly
toxic forms of As by the isolated bacteria from As-affected areas. We isolated two new Grampositive
bacteria, which are reported here (Bacillus sp. and Bacillus cereus), with As5+ minimum
inhibitory concentrations (MICs) of 4500 mg/L for the Bacillus sp. and 1000 mg/L for Bacillus cereus;
meanwhile, for As3+, the MICs are 600 mg/L for both isolates. Bacillus sp. and Bacillus cereus can also
effectively convert the highly toxic and easily mobile As3+ to As5+ in aqueous media. This study also
demonstrates that these bacteria can remove a significant proportion of As3+ and As5+ (averaging
50% for both) from aqueous media. These As-resistant bacteria from the As-affected area can be used
and upscaled for the treatment of As for a safer drinking water supply.