Enhanced Fe(0)-based autotrophic Cr(VI) biorduction with eggshell as an alternative inorganic carbon source: bioavailability mechanisms and microbial response.

Eggshell as an inorganic carbon source enhances zerovalent iron-based Cr(VI) bioreduction, achieving 100% removal and 3.3-fold faster rates than traditional bicarbonate or carbonate sources.

• Why it matters: Effective remediation of Cr(VI) in groundwater requires improved delivery of inorganic carbon and microbial activity, yet sustainable, cost-effective solutions are limited.
• What they did: The study used bioreactors with eggshell, bicarbonate, and carbonate supplements over three 48-hour cycles, analyzing removal efficiency, microbial activity, and gene expression to assess performance.
• The result: Eggshell significantly boosted Cr(VI) reduction, biofilm formation, and electron transfer, revealing a promising waste-based strategy that leverages organic and trace elements for enhanced bioremediation.