Biological carbon capture and utilization technologies hold transformative potential for achieving sustainable decarbonization while advancing the development of a sustainable biorefinery. Anaerobic microbiota capable of converting gaseous carbon emissions into biofuels and platform chemicals remain underexplored, representing an immense latent resource. C3AnaeroBio proposes a multimodal approach that integrates systems biology with model-driven culturomics to: 1) deepen our understanding of the interplay between environmental factors and microbial dynamics, 2) uncover molecular drivers of anaerobic pathways, and 3) unlock efficient carbon bioconversion systems. High-throughput single-cell technologies will enable the isolation and characterization of yet-uncultivated anaerobes, providing critical insights into microbe-prophage interactions and metabolic niche overlaps. By combining metabolic flux balance modeling with biochemical validation, biochemical validation, exchanged metabolites, microbial interactions, and metabolic networks will be systematically mapped. Custom inocula will be developed to optimize gaseous carbon bioconversion into biomethane and platform chemicals such as acetate and butyrate through targeted biosynthesis pathways. C3AnaeroBio will create predictive tools for designing specialized anaerobic consortia at the strain level. To further enhance precision, phages capable of selectively eliminating undesirable community members will be identified and tested. These data-driven strategies will enable the ad hoc assembly of consortia to streamline carbon capture processes, accelerating the transition to a sustainable biorefinery. Preliminary data suggest that C3AnaeroBio can achieve at least a 10% improvement in gaseous carbon fixation compared to current technologies. The insights gained are poised to propel innovations in the capture and bioconversion of industrial waste streams, serving as a pivotal milestone towards a circular bioeconomy.