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Updated: Aug 5, 2026

An Anaerobic Biosensor Assay for the Detection of Mercury and Cadmium
Published on: December 17, 2018
AI-2 type quorum-sensing signal enhances mercury resistance and adsorption in thermotolerant Bacillus subtilis
Shuo Han1, Qianyun Mo1, Xiaobin Wen1
1Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen, Guangdong 518055, PR China; Key Laboratory of Marine Microbial Ecology and Applied Technology, Department of Education of Guangdong Province, Shenzhen, Guangdong 518055, PR China.
Abstract:
Heavy metal contamination in coastal sediments threatens marine microbes and ecological health. Elucidating microbial community synergistic resistance mechanisms is essential for developing novel bioremediation strategies. Microorganisms are known to regulate population-level adaptation to environmental stress through quorum-sensing signals, yet the role of autoinducer-2 (AI-2) in mercury (Hg) resistance and immobilization remains poorly understood. Here, we isolated a thermotolerant Bacillus subtilis strain from coastal sediments and demonstrated that Hg stress selectively activated luxS-associated AI-2 production. AI-2 addition enhanced bacterial survival under combined Hg and heat stress by reducing intracellular reactive oxygen species, increasing antioxidant enzyme activities, promoting biofilm formation, and strengthening Hg adsorption. Sediment microcosm validation further showed that the B. subtilis + AI-2 treatment reduced soluble Hg by 29.6% after 24 h and increased the biomass-associated Hg fraction. These results reveal an AI-2-associated microbial strategy that links intracellular detoxification with extracellular Hg immobilization. While further genetic validation is needed to establish its causal role, this mechanism provides mechanistic insight for microbiome-assisted mercury remediation in thermally dynamic coastal sediments.
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