Fig. 6. ²H-acetate tracing suggests acetate oxidation by low abundance organism via Si-citrate synthase.

a Proposed pathways and deuterium labelling for acetate oxidation via the reverse Wood–Ljungdahl pathway and TCA cycle. Black circles indicate carbons with heavy (²H) hydrogen, red circles indicate carbons with ²H hydrogen produced via Re-citrate synthase, blue circles indicate carbons with ²H hydrogen produced via Si-citrate synthase, grey circles indicate carbons with ¹H (unlabelled) hydrogen. b Time-series mass isotopomer distributions of selected TCA cycle metabolites during isotope tracer experiments with sodium acetate-d3 (CD₃COOH). All measured metabolite MIDs represent the average of 2 independent biological replicate experiments. Metabolite MIDs and standard errors can be found in Supplementary Dataset 3. Reaction hydrogen atom transitions are provided in Supplementary Dataset 4.