Novel Engineered Living Materials for Integrated Detection, Remediation, and Recovery of Cadmium Pollution

ABSTRACT Heavy‐metal emissions pose severe environmental hazards, with Cd 2+ contamination being particularly critical. However, current strategies for Cd 2+ detection and remediation remain limited and often inflict secondary ecological damage. Here, we engineered Bacillus subtilis as a chassis to construct a Cd 2+ ‐responsive biosensor (CJSora) by integrating the endogenous promoter of cadA (pcadA) with a T7RNAP ‐based signal amplification module. The resulting sensor enables monitoring of environmental Cd 2+ with high specificity and sensitivity across a 0–100 µM range. To achieve intelligent detection and remediation, we further developed an engineered living material (CJSsorX) capable of autonomous response to Cd 2+ pollution. Under low Cd 2+ conditions (e.g., agricultural soils), surface‐displayed Cd 2+ ‐binding protein CadR efficiently captures and recovers Cd 2+ from the environment. When Cd 2+ levels exceed the adsorption capacity, intracellular overexpression of the aerobic sulfate reduction pathway ( CysE and PatB ) catalyzes the biomineralization of Cd 2+ into CdS nanoparticles, enabling spatially modular remediation with enhanced efficiency and sustainability. After remediation, Cd 2+ can be reclaimed using a functional peptide (TVNFKLY) with specific affinity for Fe 3 O 4 magnetic nanoparticles. As a proof of concept, CJSsorX was applied to the removal of Cd 2+ from contaminated soils and wastewater. The engineered material achieved 83.64% removal in soils and up to 99.56% removal in water. Overall, this work establishes a B. subtilis –based intelligent living material with integrated sensing, remediation, and recovery capabilities, offering a promising and sustainable strategy for combating Cd 2+ pollution.