title: Cre-lox66/lox71-based elimination of phosphotransacetylase or acetaldehyde dehydrogenase shifted carbon flux in acetogen rendering selective overproduction of ethanol or acetate.
abstract: Acetogen strain Clostridium sp. MT1121 produced 300 mM acetate (p<0.005) and 321 mM ethanol (p<0.005) from synthesis gas (syngas) blend 60 % CO and 40 % H(2). Clostridium sp. MT1121 was metabolically engineered to eliminate production of either acetate or acetaldehyde during syngas fermentation. We used Cre-lox66/lox71-based gene removal system to eliminate either phosphotransacetylase (pta), or acetaldehyde dehydrogenase (aldh). The resulted biocatalyst with eliminated pta increased ethanol yield to 610 mM (p<0.005). Inactivation of pta rendered only 502 mM of ethanol (p<0.005). The acetogen biocatalyst with eliminated aldh produced 450 mM acetate (p<0.005). The role of cell energy pool preservation for re-directed carbon flux is discussed. This is the first report on time- and cost-efficient gene elimination in acetogens using lox66/lox71 gene elimination system.
authors.affiliation: Syngas Biofuels Energy, Inc., 2441 Del Monte, Houston, TX 77019, USA.
authors.forename: Vel
authors.initials: V
authors.lastname: Berzin
authors.forename: Michael
authors.initials: M
authors.lastname: Kiriukhin
authors.forename: Michael
authors.initials: M
authors.lastname: Tyurin
mesh_terms: D000085:Acetates / Q000378:metabolism*; D000096:Acetone / Q000378:metabolism*; D000445:Aldehyde Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D003013:Clostridium / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D055786:Gene Knockout Techniques / Q000379:methods*; D060847:Metabolic Engineering; D010709:Phosphate Acetyltransferase / Q000235:genetics* / Q000378:metabolism
chemical_list: D000085:Acetates; D001426:Bacterial Proteins; D000096:Acetone; D000431:Ethanol; D000445:Aldehyde Oxidoreductases; C018699:aldehyde dehydrogenase (NAD(P)+); D010709:Phosphate Acetyltransferase