PHB accumulation of E. coli JM109 expressing different PhaC2
s using gluconate as carbon source. Data represent results for three independent experiments ± standard deviations. The cultivation was conducted in 500 ml shake flasks each having 50 ml MS medium containing 20 g/l gluconate and 100 mg/l thiamine. IPTG (0.1 mol/l) was used as an inducing agent for lac promoter and was added at 6 h after inoculation. After 48 h cultivation, strains harboring pYC2OH showed the highest CDW and PHB content (30 wt%, approximately 16-fold of the strains harboring pYC2), and the effect of codon optimization and hairpin stabilization was about 2.6-fold compared to the strain harboring pYC2QKST (p < 0.01).