title: Tetanus toxin production is triggered by the transition from amino acid consumption to peptides.
abstract: Bacteria produce some of the most potent biomolecules known, of which many cause serious diseases such as tetanus. For prevention, billions of people and countless animals are immunised with the highly effective vaccine, industrially produced by large-scale fermentation. However, toxin production is often hampered by low yields and batch-to-batch variability. Improved productivity has been constrained by a lack of understanding of the molecular mechanisms controlling toxin production. Here we have developed a reproducible experimental framework for screening phenotypic determinants in Clostridium tetani under a process that mimics an industrial setting. We show that amino acid depletion induces production of the tetanus toxin. Using time-course transcriptomics and extracellular metabolomics to generate a 'fermentation atlas' that ascribe growth behaviour, nutrient consumption and gene expression to the fermentation phases, we found a subset of preferred amino acids. Exponential growth is characterised by the consumption of those amino acids followed by a slower exponential growth phase where peptides are consumed, and toxin is produced. The results aim at assisting in fermentation medium design towards the improvement of vaccine production yields and reproducibility. In conclusion, our work not only provides deep fermentation dynamics but represents the foundation for bioprocess design based on C. tetani physiological behaviour under industrial settings.
authors: Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia; National Laboratory of Genomics for Biodiversity (LANGEBIO), Cinvestav-IPN, Irapuato, Mexico.
authors: Cuauhtemoc
authors: C
authors: Licona-Cassani
authors: Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia.
authors: Jennifer A
authors: JA
authors: Steen
authors: Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia.
authors: Nicolas E
authors: NE
authors: Zaragoza
authors: Zoetis, 45 Poplar Road, Parkville, VIC 3052, Australia.
authors: Glenn
authors: G
authors: Moonen
authors: Zoetis, 45 Poplar Road, Parkville, VIC 3052, Australia.
authors: George
authors: G
authors: Moutafis
authors: Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia; Metabolomics Australia Queensland Node, AIBN, The University of Queensland, Brisbane, QLD 4072, Australia.
authors: Mark P
authors: MP
authors: Hodson
authors: Zoetis, 45 Poplar Road, Parkville, VIC 3052, Australia.
authors: John
authors: J
authors: Power
authors: Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia.
authors: Lars K
authors: LK
authors: Nielsen
authors: Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia. Electronic address: e.marcellin@uq.edu.au.
authors: Esteban
authors: E
authors: Marcellin
mesh_terms: D000222:Adaptation, Physiological; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry / Q000502:physiology; D003017:Clostridium tetani / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D004734:Energy Metabolism; D005285:Fermentation; D007501:Iron / Q000378:metabolism; D009842:Oligopeptides / Q000737:chemistry / Q000502:physiology; D010957:Plasmids / Q000235:genetics; D013744:Tetanus Toxin / Q000096:biosynthesis* / Q000235:genetics; D059467:Transcriptome; D037521:Virulence Factors / Q000235:genetics
chemical_list: D000596:Amino Acids; D003470:Culture Media; D009842:Oligopeptides; D013744:Tetanus Toxin; D037521:Virulence Factors; D000255:Adenosine Triphosphate; D007501:Iron
keywords: Clostridium tetani; Fermentation maps; Systems biology; TeTN production