Siderophore-assisted cadmium hyperaccumulation in Bacillus subtilis

Area of Science:

• Microbiology
• Environmental Science
• Biotechnology

Background:

• Siderophores are low molecular weight compounds with high iron-binding affinity, produced by microorganisms under iron scarcity.
• Their metal-chelating properties suggest potential applications beyond iron transport, including bioremediation.

Purpose of the Study:

• To investigate the efficacy of hydroxamate siderophore from Aspergillus nidulans in facilitating cadmium (Cd) bioremediation by Bacillus subtilis.
• To explore siderophore-mediated intracellular Cd accumulation and its impact on bacterial growth and biochemical parameters.

Main Methods:

• Treatment of Bacillus subtilis cells with Aspergillus nidulans-derived hydroxamate siderophore.
• Assessment of intracellular Cd accumulation using atomic absorption spectroscopy.
• Biochemical assays including lipid peroxidation, total protein, carbohydrate, and iron content.
• In silico docking and STRING analyses to predict molecular interactions.

Main Results:

• Bacillus subtilis exhibited significantly higher intracellular accumulation of cadmium ions in the presence of hydroxamate siderophore.
• In silico studies confirmed specific interactions between the siderophore and B. subtilis receptors, with higher affinity for Cd²⁺ than Fe³⁺.
• Experimental data supported in silico findings, indicating enhanced Cd sequestration by siderophore-treated bacteria.

Conclusions:

• Hydroxamate siderophores can be utilized to enhance bacterial cadmium bioremediation by promoting intracellular Cd accumulation.
• This approach offers a promising strategy for developing novel bioremediation techniques for heavy metal pollution.
• The study highlights the potential of siderophores in environmental metal sequestration.