title: Engineering Propionibacterium freudenreichii subsp. shermanii for enhanced propionic acid fermentation: effects of overexpressing propionyl-CoA:Succinate CoA transferase.
abstract: Propionibacterium freudenreichii subsp. shermanii naturally forms propionic acid as the main fermentation product with acetate and succinate as two major by-products. In this study, overexpressing the native propionyl-CoA:succinate CoA transferase (CoAT) in P. shermanii was investigated to evaluate its effects on propionic acid fermentation with glucose, glycerol, and their mixtures as carbon source. In general, the mutant produced more propionic acid, with up to 10% increase in yield (0.62 vs. 0.56g/g) and 46% increase in productivity (0.41 vs. 0.28g/Lh), depending on the fermentation conditions. The mutant also produced less acetate and succinate, with the ratios of propionate to acetate (P/A) and succinate (P/S) in the final product increased 50% and 23%, respectively, in the co-fermentation of glucose/glycerol. Metabolic flux analysis elucidated that CoAT overexpression diverted more carbon fluxes toward propionic acid, resulting in higher propionic acid purity and a preference for glycerol over glucose as carbon source.
authors.affiliation: William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 140 W 19th Avenue, Columbus, OH 43210, USA.
authors.forename: Zhongqiang
authors.initials: Z
authors.lastname: Wang
authors.affiliation: William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 140 W 19th Avenue, Columbus, OH 43210, USA.
authors.forename: Ehab M
authors.initials: EM
authors.lastname: Ammar
authors.affiliation: William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 140 W 19th Avenue, Columbus, OH 43210, USA.
authors.forename: An
authors.initials: A
authors.lastname: Zhang
authors.affiliation: William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 140 W 19th Avenue, Columbus, OH 43210, USA; School of Pharmaceutical Engineering and Life Sciences, Changzhou University, 1 Ge Hu Road, Jiangsu 213164, China.
authors.forename: Liqun
authors.initials: L
authors.lastname: Wang
authors.affiliation: William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 140 W 19th Avenue, Columbus, OH 43210, USA.
authors.forename: Meng
authors.initials: M
authors.lastname: Lin
authors.affiliation: William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 140 W 19th Avenue, Columbus, OH 43210, USA. Electronic address: yang.15@osu.edu.
authors.forename: Shang-Tian
authors.initials: ST
authors.lastname: Yang
mesh_terms: D015256:Coenzyme A-Transferases / Q000235:genetics / Q000378:metabolism*; D005285:Fermentation / Q000502:physiology; D005947:Glucose / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D060847:Metabolic Engineering; D011422:Propionates / Q000378:metabolism*; D011424:Propionibacterium / Q000201:enzymology* / Q000235:genetics
chemical_list: D011422:Propionates; D015256:Coenzyme A-Transferases; D005947:Glucose; C029658:propionic acid; D005990:Glycerol
keywords: Metabolic engineering; Metabolic flux analysis; Propionibacterium shermanii; Propionic acid fermentation; Propionyl-CoA:succinate CoA transferase