Carbon fixation and electrogenesis by Clamydomonas reinhardtii and Microcystis aeruginosa coupled with Shewanella oneidensis MR-1

Biophotovoltaics (BPV) and microbial fuel cells (MFCs) both represent promising sustainable energy technologies. However, BPV is limited by the weak electrogenic capacity of phototrophic microorganisms, while MFC faces challenges related to high substrate costs and difficulties in maintaining a continuous and stable supply of substrates. In this study, Microcystis aeruginosa and Chlamydomonas reinhardtii were each paired with Shewanella oneidensis MR-1 to construct alga–bacteria MFC systems. The combination of C. reinhardtii and S. oneidensis MR-1 produced the highest power output, reaching 73.6 mA·m⁻² after a stabilization period, outperforming all other configurations tested. This combination also demonstrated excellent CO₂ fixation, with net CO₂ concentration reduced by up to 272.3 % compared with the C. reinhardtii-only system. Metabolomics data further revealed that the presence of S. oneidensis MR-1 caused a substantial reduction in metabolites classified under “Nucleosides, nucleotides, and analogs” and “Organic acids and derivatives,” indicating its metabolic utilization of these compounds. The research not only offers a sustainable solution but also provides new perspectives for advancing sustainable energy technologies.