title: Role of extracellular cues to trigger the metabolic phase shifting from acidogenesis to solventogenesis in Clostridium acetobutylicum.
abstract: Clostridium acetobutylicum exhibits a two-step metabolic pathway where substrates are first converted to organic acids accompanied by a decrease in pH. The acids are then assimilated to organic solvents. The transition from the acid-producing (acidogenesis) to the solvent-producing phase (solventogenesis) is controlled by integration of a number of cellular and environmental cues, whose precise mode of action are not well understood. In this study, a series of batch experiments were performed to understand the impact of extracellular cues in regulating the dynamics of acidogenesis and solventogenesis. It is demonstrated that the two phases operate independently of each other and the growth phase of the cell, i.e. the cues controlling a phase are not linked to the status of the other phase or the growth phase of the cell. Kinetic experiments demonstrated that there exist two previously uncharacterized negative feedback loops controlling the amounts of acids produced in the acidogenesis phase.
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology Gandhinagar, Ahmedabad 382424, India.
authors.forename: Manish
authors.initials: M
authors.lastname: Kumar
authors.forename: Kalyan
authors.initials: K
authors.lastname: Gayen
authors.forename: Supreet
authors.initials: S
authors.lastname: Saini
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D000143:Acids / Q000378:metabolism*; D020148:Butyric Acid / Q000378:metabolism; D050260:Carbohydrate Metabolism / Q000187:drug effects; D046969:Clostridium acetobutylicum / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism*; D025461:Feedback, Physiological / Q000187:drug effects; D005285:Fermentation / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D053858:Metabolic Networks and Pathways / Q000187:drug effects; D012997:Solvents / Q000378:metabolism*; D013312:Stress, Physiological / Q000187:drug effects
chemical_list: D000143:Acids; D012997:Solvents; D020148:Butyric Acid; D005947:Glucose; D019342:Acetic Acid