biostudies-literatureUnknown110(1)Diniz BCIn methanogenic communities, two main pathways drive methanogenesis: acetoclastic methanogenesis, which converts acetate into CH₄ and CO₂, and hydrogenotrophic methanogenesis, which reduces CO₂ with H₂ to CH₄. Under high-pH conditions, a shift in dominance from acetoclastic to hydrogenotrophic methanogenesis is often observed. The goal of this work was to identify the pH tipping point for this metabolic shift and to elucidate the influence of alkalinity on this transition in a haloalkaliphilic methanogenic community enriched from anaerobic soda lake sediments. To this end, a haloalkaliphilic microbial community was cultivated across a pH range (8.20-10.00) at three different alkalinities (0.1, 0.6, 1.2 eq/L). Specific qPCR probes were Applied microbiology and biotechnology66https://www.ebi.ac.uk/biostudies/studies/S-EPMC12909423biostudies-literatureAcetoclastic versus hydrogenotrophic methanogenesis: defining how pH and alkalinity shape acetate metabolism in a haloalkaliphilic methanogenic community for biomethane production.PMC12909423Zantout-Wilfert PDiniz BCAbbas Bvan Loosdrecht MCMSorokin DYfalseAcetoclastic versus hydrogenotrophic methanogenesis: defining how pH and alkalinity shape acetate metabolism in a haloalkaliphilic methanogenic community for biomethane production.In methanogenic communities, two main pathways drive methanogenesis: acetoclastic methanogenesis, which converts acetate into CH₄ and CO₂, and hydrogenotrophic methanogenesis, which reduces CO₂ with H₂ to CH₄. Under high-pH conditions, a shift in dominance from acetoclastic to hydrogenotrophic methanogenesis is often observed. The goal of this work was to identify the pH tipping point for this metabolic shift and to elucidate the influence of alkalinity on this transition in a haloalkaliphilic methanogenic community enriched from anaerobic soda lake sediments. To this end, a haloalkaliphilic microbial community was cultivated across a pH range (8.20-10.00) at three different alkalinities (0.1, 0.6, 1.2 eq/L). Specific qPCR probes were 2026-01-01T00:00:00Z2026 Feb2026-07-09T13:11:11.999Z2026-07-09T13:09:53.451ZS-EPMC129094234169737610.1007/s00253-026-13725-0