Cre-lox66/lox71-based elimination of phosphotransacetylase or acetaldehyde dehydrogenase shifted carbon flux in acetogen rendering selective overproduction of ethanol or acetate.

Vel Berzin, Michael Kiriukhin, Michael Tyurin

Syngas Biofuels Energy, Inc., 2441 Del Monte, Houston, TX 77019, USA.

Applied biochemistry and biotechnology 2012 Nov

filter terms:

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.

Citation

Vel Berzin, Michael Kiriukhin, Michael Tyurin. Cre-lox66/lox71-based elimination of phosphotransacetylase or acetaldehyde dehydrogenase shifted carbon flux in acetogen rendering selective overproduction of ethanol or acetate. Applied biochemistry and biotechnology. 2012 Nov;168(6):1384-93