title: Enzymatic synthesis of L-lactic acid from carbon dioxide and ethanol with an inherent cofactor regeneration cycle.
abstract: Efficient conversion of carbon dioxide is of great interests to today's endeavors in controlling greenhouse gas emission. A multienzyme catalytic system that uses carbon dioxide and ethanol to produce L-lactate was demonstrated in this work, thereby providing a novel reaction route to convert bio-based ethanol to an important building block for synthesis biodegradable polymers. The synthetic route has a unique internal cofactor regeneration cycle, eliminating the need of additional chemical or energy for cofactor regeneration. Lactate was successfully synthesized with 41% of ethanol converted in a batch reaction, while a turnover number of 2.2 day⁻¹ was reached for cofactor regeneration in a reaction with continuous feeding of ethanol. A kinetic model developed based on reaction kinetic parameters determined separately for each reaction step predicted well the reaction rates and yields of the multienzyme reaction system.
authors.affiliation: Department of Bioproducts and Biosystems Engineering, Biotechnology Institute, University of Minnesota-Twin Cities, St Paul, 55108, USA.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Tong
authors.forename: Bilal
authors.initials: B
authors.lastname: El-Zahab
authors.forename: Xueyan
authors.initials: X
authors.lastname: Zhao
authors.forename: Youyan
authors.initials: Y
authors.lastname: Liu
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
mesh_terms: D019149:Bioreactors; D001709:Biotechnology / Q000379:methods; D002245:Carbon Dioxide / Q000378:metabolism*; D003067:Coenzymes / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D007700:Kinetics; D019344:Lactic Acid / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism*; D009243:NAD / Q000378:metabolism*
chemical_list: D003067:Coenzymes; D009097:Multienzyme Complexes; D009243:NAD; D002245:Carbon Dioxide; D019344:Lactic Acid; D000431:Ethanol