title: Metabolic pathways of clostridia for producing butanol.
abstract: Worldwide demand for energy has been the impetus for research to produce alcohol biofuels from renewable resources. This review focuses on the biosynthesis of butanol, which is regarded to be superior to ethanol as a fuel. Although acetone/butanol fermentation is one of the oldest large-scale fermentation processes, butanol yield by anaerobic fermentation remains sub-optimal. Metabolic engineering provides a means for fermentation improvements. Consequently, a comprehensive assessment of the intermediary enzymes involved in butanol formation from carbohydrates by the saccharolytic bacterium, Clostridium acetobutylicum and other closely allied clostridia was performed to provide guidelines for potentially enhancing butanol productivity. The activity of the enzymes, their regulation and contribution to the metabolic pathways was reviewed. Published kinetic data for each important enzymatic reaction were assessed. For most enzymatic reactions, the systematic investigation of the kinetic data and the properties of the enzymes led to the development of rate equations that were able to describe activity as the function of the substrates, products, and allosteric effectors.
authors.affiliation: Department of Chemical Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1; Department of Chemical Engineering, Ferdowsi University of Mashhad, Azadi Square, Pardis Campus, Mashhad, Postal Code 9177948944, Khorasan, Iran. Electronic address: rgheshla@engmail.uwaterloo.ca.
authors.forename: R
authors.initials: R
authors.lastname: Gheshlaghi
authors.affiliation: Department of Chemical Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1. Electronic address: jscharer@uwaterloo.ca.
authors.forename: J M
authors.initials: JM
authors.lastname: Scharer
authors.affiliation: Department of Chemical Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1. Electronic address: mooyoung@uwaterloo.ca.
authors.forename: M
authors.initials: M
authors.lastname: Moo-Young
authors.affiliation: Department of Chemical Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1. Electronic address: cpchou@uwaterloo.ca.
authors.forename: C P
authors.initials: CP
authors.lastname: Chou
mesh_terms: D000440:Butanols / Q000378:metabolism*; D003013:Clostridium / Q000201:enzymology / Q000378:metabolism*; D005285:Fermentation; D007700:Kinetics
chemical_list: D000440:Butanols