Rapid enrichment of ternary carbon-fixing microbial consortia from anaerobic sludge via pressurized pre-autotrophic strategy for scalable microbial electrosynthesis.

Abstract

As a promising platform for microbially catalyzed carbon capture, microbial electrosynthesis (MES) is constrained by inoculation strategies that limit carbon fixation efficiency and scalability. Mixed-culture inocula outperform pure cultures in functional redundancy and ecological resilience in large systems, but slow acclimation and erratic community composition yield inconsistent performance. Here, this study present a pressurized pre-autotrophic (PA) strategy that rapidly enriches carbon-fixing microorganisms (CFMs) from anaerobic sludge, in comparison with direct autotrophic (DA) and electrode reversal (ER) strategies. PA increased CFM abundance to 51%, 3.5-fold higher than in DA-MES and ER-MES (both 15%). Acetate production in PA-MES reached 14.47 g·m -2 ·d -1 . In addition to enhanced acetate productivity, PA-MES exhibited superior electrochemical performance, achieving the highest Faradaic efficiency for acetate and energy efficiency among the tested systems, together with the lowest energy consumption per unit acetate. Metagenomic analysis revealed a PA-defined core community with coordinated activation of the Wood-Ljungdahl, rTCA, and methanogenic pathways, providing redundant routes for stable CO 2 fixation. By transforming mixed-culture inocula into a functionally cohesive carbon-fixing community, the PA strategy enables rapid startup and sustained carbon fixation, offering a practical framework for scalable MES.

Keywords

Identifiers

DOI

10.1016/j.biortech.2026.134276

PubMed

41747903

Journal

Bioresource technology

Year

2026