Multidimensional exploration of Tc(VII) bio-reduction: Kinetics and cellular responses

Area of Science:

• Environmental Science
• Microbiology
• Biochemistry

Background:

• Technetium-99 (⁹⁹Tc) is a mobile, long-lived radionuclide posing environmental risks.
• Microbial processes are critical for understanding technetium's environmental fate.

Purpose of the Study:

• To investigate the environmental factors affecting Tc(VII) bio-reduction kinetics.
• To explore cellular responses to Tc(VII) exposure using multi-omics analysis in Bacillus cereus X-68.

Main Methods:

• Assessed Tc(VII) bio-reduction under various environmental conditions.
• Utilized multi-omics analysis to study cellular responses to Tc(VII).
• Investigated the role of electron transport mediators (e.g., AQS, riboflavin).

Main Results:

• Bacillus cereus X-68 reduced Tc(VII) to Tc(IV) hydrate intracellularly via pH- and temperature-dependent enzymatic activity.
• Electron transport mediators significantly enhanced Tc(VII) reduction rates.
• Tc(VII) exposure downregulated key cellular processes and induced metabolic reprogramming, enhancing NADH/NADPH synthesis.

Conclusions:

• Elucidated biochemical mechanisms of Tc-microbe interactions.
• Provided insights into Tc(VII) bio-reduction and accumulation.
• Informed strategies for environmental radioactive contamination assessment and mitigation.