Harnessing Fermentation May Enhance the Performance of Biological Sulfate-Reducing Bioreactors

Area of Science:

• Environmental microbiology
• Bioremediation
• Metagenomics

Background:

• Biological sulfate reduction (BSR) is a key bioremediation strategy for sulfate-rich waste.
• The influence of microbial metabolic interactions on BSR performance remains poorly understood.
• Understanding these interactions is crucial for optimizing bioreactor efficiency.

Purpose of the Study:

• To investigate the impact of metabolic interactions on BSR performance in reactors.
• To characterize microbial communities and their metabolic roles in sulfate-contaminated solutions.
• To explore the potential of enhancing BSR using fermentable substrates and syntrophic relationships.

Main Methods:

• Genome-resolved metagenomics was employed to analyze 17 microbial communities.
• Reactors were fed synthetic sulfate-contaminated solutions with lactate or acetate.
• Analysis focused on hydrogenase genes, electron donor oxidation, and sulfate reduction kinetics.

Main Results:

• Diverse bacteria encoding hydrogenases and sulfate-reducing microorganisms (SRM) capable of H2 uptake were identified.
• Electron donor oxidation varied across reactor zones, but sulfate reduction kinetics remained consistent.
• Sustained BSR performance was observed in acetate-supplemented reactors, linked to H2 consumption by SRM.

Conclusions:

• Metabolic interactions, particularly H2 cycling via syntrophy, significantly support BSR performance.
• Addition of fermentable substrates can enhance BSR reactor efficiency, especially when using acetate.
• This study provides insights into optimizing bioremediation strategies for sulfate waste streams.