Fig. 1

Metabolic map representing the main mechanisms that connect the xylose consumption pathway with the PHB producing pathway. Two alternative xylose reductases (XR) are represented: wild-type XR from S. stipitis present in TMB4443 and a mutated version of it that has different cofactor affinity present in TMB4425. The size of the size of the letters in the XR alternatives represent the preference for NADPH or NADH (bigger size → higher affinity). Two alternative acetoacetyl-CoA reductases that are part of the PHB producing pathway from acetyl-CoA are also shown: the first from Cupriviadus necator (present in TMB4443) and the second from Allochromatium vinosum (present in TMB4425). The dashed arrows represent more than one metabolic reaction in order to simplify the scheme