Fig. 4

Fine tuning of pykF expression strength to improve succinate production and attenuate accumulation of lactate and acetate. a Two anti-pykF sRNA plasmids were designed and constructed at different expression levels by combinations of promoters and plasmid copy number. (H) and (L) represented high-copy-number plasmid (pRSF) and low-copy-number plasmid (pBldgbrick2), respectively. b Relative yields of succinate, lactate and acetate. BKS12 was compared to BKS8 and BKS13 and BKS14 were compared to BKS12. c Yields of succinate, lactate and acetate. The significance was compared to BKS11. d Titers of succinate, lactate and acetate. The significance was compared to BKS11. Error bars represent SD for three replicates. Asterisks indicate p-values (**p < 0.01, *p < 0.05)