Augmented elimination of cadmium and mercury by Cytobacillus firmus and Paenibacillus massiliensis isolated from heavy metal contaminated soil samples

Abstract

Cadmium and mercury, often classified as heavy metals or toxic elements, are prevalent in the environment due to industrial activities and pollution, posing risks to ecosystems and human health. The current research utilized the metal tolerance abilities of extremely resilient microorganisms, both individually and as part of a consortium, to address the complex issue of heavy metal pollution remediation. These bacterial strains were isolated from contaminated soil and subjected to screening under different treatment conditions. The examination and screening investigations have unveiled an isolated strain as Cd resistant bacteria viz. BS4 (Cytobacillus firmus) which have shown Cd removal up to 82 % and Hg tolerant bacterial isolate namely, BS10 (Paenibacillus massiliensis) with Hg removal efficiency of more than 63 %. Furthermore, the engineered microbial consortium (BS4 + BS10) has proven its capability to enhance the removal of Cd and Hg from soil samples. Extensive validation considered various factors such as pH, temperature, initial concentrations of Cd and Hg, and size of the inoculum, establishing the consortium's biosorption capacity. Structural alterations induced by microbial treatment were evidenced through FESEM and FTIR analysis. The metal-binding proficiency exhibited by this bacterial consortium underscores its potential as an efficient biosorbent for addressing heavy metal contamination.