Metabolic Engineering of Escherichia coli for Poly(3-hydroxybutyrate)‎ Production under Microaerobic Condition

Abstract EN

The alcohol dehydrogenase promoter P adhE and mixed acid fermentation pathway deficient mutants of Escherichia coli were employed to produce poly(3-hydroxybutyrate) (P3HB) under microaerobic condition.

The E.

coli mutant with ackA-pta, poxB, ldhA, and adhE deletions accumulated 0.67 g/L P3HB, up to 78.84% of cell dry weight in tube cultivation.

The deletion of pyruvate formate-lyase gene pflB drastically decreased P3HB production and P3HB content to 0.09 g/L and 24.44%, respectively.

Overexpressing pflB via the plasmid in its knocked out mutant restored cell growth and P3HB accumulation, indicating the importance of the pyruvate formate-lyase in microaerobic carbon metabolism.

The engineered E.

coli BWapld (pWYC09) produced 5.00 g/L P3HB from 16.50 g/L glucose in 24 h batch fermentation, and P3HB production yield from glucose was 0.30 g/g, which reached up to 63% of maximal theoretical yield.