Acetate formation during recombinant protein production in K-12 with an elevated NAD(H) pool.

Acetate formation is a disadvantage in the use of for recombinant protein production, and many studies have focused on optimizing fermentation processes or altering metabolism to eliminate acetate accumulation. In this study, MEC697 (MG1655 ) maintained a larger pool of NAD(H) compared to the wild-type control, and also accumulated lower concentrations of acetate when grown in batch culture on glucose. In steady-state cultures, the elevated total NAD(H) found in MEC697 delayed the threshold dilution rate for acetate formation to a growth rate of 0.

Conversion of glucose-xylose mixtures to pyruvate using a consortium of metabolically engineered .

Two strains of were engineered to accumulate pyruvic acid from two sugars found in lignocellulosic hydrolysates by knockouts in the , , , and genes. Additionally, since glucose and xylose are typically consumed sequentially due to carbon catabolite repression in , one strain (MEC590) was engineered to grow only on glucose while a second strain (MEC589) grew only on xylose. On a single substrate, each strain generated pyruvate at a yield of about 0.