mixed-acid fermentation

Edge evidence

• mixed-acid fermentation participates in fermentation biolink:participates_in

  Mixed-acid fermentation is a class of fermentation metabolism.

  • DOI:10.3389/fmicb.2021.703525 Energy-conservation review lists the mixed-acid product spectrum.
• mixed-acid fermentation produces mixed acid + ethanol + CO2/H2 products METPO:2000202

  The pathway yields the characteristic acid + ethanol + gas spectrum.

  • DOI:10.3390/molecules31020333 Classical-fermentation review describes mixed-acid fermentation by enterobacteria.
• mixed-acid fermentation has output pyruvate

  Glycolysis upstream of mixed-acid fermentation produces pyruvate.

  • DOI:10.35812/cellulosechemtechnol.2024.58.90 Pyruvate, ATP, and NADH are produced when glucose or other carbon sources reach the primary glycolytic pathway.
• pyruvate formate lyase (PflB) catalyzes conversion of pyruvate

  PflB cleaves pyruvate into formate and acetyl-CoA.

  • DOI:10.1128/iai.00176-23 Pyruvate formate lyase (PflB) catalyzes the conversion of pyruvate into formate and acetyl-CoA.
• pyruvate formate lyase (PflB) produces formate METPO:2000202

  PflB cleavage of pyruvate yields formate.

  • DOI:10.1128/iai.00176-23 Pyruvate formate lyase (PflB) catalyzes the conversion of pyruvate into formate and acetyl-CoA.
• phosphotransacetylase / acetate kinase (Pta/AckA) converts acetate

  Pta and AckA convert acetyl-CoA to acetate (with ATP generation).

  • DOI:10.1128/iai.00176-23 Acetyl-CoA is further metabolized by Pta and AckA to generate acetate.
• formate induces synthesis of formate hydrogenlyase complex (FHL)

  Formate induces synthesis of the membrane-bound FHL complex.

  • DOI:10.1128/aem.01472-24 Formate induces the synthesis of the membrane-bound FHL complex that catalyzes formate disproportionation into CO2 and H2.
• formate hydrogenlyase complex (FHL) produces molecular hydrogen METPO:2000202

  FHL disproportionates formate into CO2 and H2.

  • DOI:10.1128/aem.01472-24 Formate is disproportionated into CO2 and H2 by the formate hydrogenlyase complex via FdhF and hydrogenase 3 (HycE).
• formate hydrogenlyase complex (FHL) produces carbon dioxide METPO:2000202

  FHL disproportionates formate into CO2 and H2.

  • DOI:10.1128/aem.01472-24 Formate is disproportionated into CO2 and H2 by the formate hydrogenlyase complex.
• acidic conditions positively regulates formate hydrogenlyase complex (FHL)

  Acidic conditions favor FHL-mediated formate cleavage.

  • DOI:10.35812/cellulosechemtechnol.2024.58.90 The enzyme complex formate:hydrogen lyase (FHL) cleaves formate under acidic conditions into H2 and CO2.
• molecular oxygen inhibits molecular hydrogen RO:0002212

  Oxygen prevents fermentative hydrogen generation.

  • DOI:10.35812/cellulosechemtechnol.2024.58.90 The presence of oxygen prevents the generation of hydrogen.
• mixed-acid fermentation lowers cytoplasmic pH

  Acid generation by MAF lowers cytoplasmic pH.

  • DOI:10.1128/iai.00176-23 MAF results in the generation of acid, which subsequently lowers the pH of the cytoplasm.
• pyruvate formate lyase (PflB) produces acetyl-CoA METPO:2000202

  Pyruvate formate-lyase cleaves pyruvate into acetyl-CoA and formate.

  • DOI:10.3389/fmicb.2021.703525 Connecting edge wiring the enrichment node into the graph.