Growth curves and isobutanol production by E. coli W (ATCC 9637) (pIZIbPSO) and S. blattae (p424IbPSO). a Growth curves in different carbon sources. Glucose (20 g l−1) (red), xylose (20 g l−1) (purple), 20% lignocellulosic hydrolysate (20 ml liquid hydrolysate/100 ml medium) (blue) and sucrose (20 g l−1) (green). b Isobutanol production of the recombinant strains at 48 h in the presence of different carbon sources. S. blattae does not use sucrose as carbon source and the isobutanol production was not determined in this medium (nd).