Anabaena / MGS-1 Anaerobic-Digestion Methanogen Consortium

An anaerobic-digestion microbial consortium studied as part of a bioregenerative life-support concept for Mars: cyanobacterial biomass (Anabaena sp.), which can be grown on Martian resources, is anaerobically digested to mobilize nutrients (ammonium and phosphate) for use as a crop fertilizer, with biogas as a co-product. Ramalho et al. (2025, Bioresource Technology) tested three microbial communities for their ability to digest Anabaena biomass in three matrices — a minimal medium, 200 g/L MGS-1 Mars regolith simulant, and water. In minimal medium the taxonomic (16S) analysis revealed a SYNTROPHIC community: fermentative bacteria degrade the cyanobacterial biomass and cross-feed hydrogenotrophic methanogenic archaea (interspecies H2/CO2 transfer driving methanogenesis). In the MGS-1 regolith matrix, however, the methanogens were outcompeted by sulfate-reducing bacteria, and the regolith also adsorbed organics and lowered phosphate/ammonium recovery. The Anabaena biomass here is the digestion FEEDSTOCK (substrate) rather than a live member of the digesting consortium. All communities produced ammonium and removed organic carbon, supporting the viability of a Mars-relevant bioprocess for fertilizer production. The specific dominant genera resolved by the paper's 16S analysis are reported in the full text, which is paywalled; only the functional guilds (fermentative bacteria, hydrogenotrophic methanogens, sulfate-reducing bacteria) are named in the openly available abstract and are therefore represented here as interactions/roles rather than as NCBITaxon-grounded members.