Wood-Ljungdahl pathway and pathways for acetate and ethanol formation. (A) Shown is the detailed representation of the Wood-Ljungdahl pathway explicitly summarizing the reducing equivalents required for carbon fixation. (B) Pathway showing acetate formation and ethanol formation from acetyl-coA. Reaction abbreviations: FDH7 (formate dehydrogenase), FTHFLi (formate-tetrahydrofolate ligase), MTHFC (methenyltetrahydrofolate cyclohydrolase), MTHFD (methylenetetrahydrofolate dehydrogenase (NADP)), MTHFR5 (5,10-methylenetetrahydrofolate reductase (Ferredoxin) Electron bifurcating), METR (Methyltetrahydrofolate:corrinoid/iron-sulfur protein methyltransferase), CODH_ACS (CODH/Acetyl-CoA synthase), PTAr (phospotransacetylase), ACKr (acetate kinase), ACALD (acetaldehyde dehydrogenase), ALCD2x (ethanol dehydrogenase). Yellow nodes indicate the oxidized form of reducing equivalents and blue nodes indicate the reduced form.