Engineering of Saccharomyces cerevisiae for the production of poly-3-d-hydroxybutyrate from xylose.

Poly-3-d-hydroxybutyrate (PHB) is a promising biopolymer naturally produced by several bacterial species. In the present study, the robust baker's yeast Saccharomyces cerevisiae was engineered to produce PHB from xylose, the main pentose found in lignocellulosic biomass. The PHB pathway genes from the well-characterized PHB producer Cupriavidus necator were introduced in recombinant S. cerevisiae strains already capable of pentose utilization by introduction of the fungal genes for xylose utilization from the yeast Scheffersomyces stipitis. PHB production from xylose was successfully demonstrated in shake-flasks experiments, with PHB yield of 1.17 ± 0.18 mg PHB g(-1) xylose. Under well-controlled fully aerobic conditions, a titer of 101.7 mg PHB L(-1) was reached within 48 hours, with a PHB yield of 1.99 ± 0.15 mg PHB g(-1) xylose, thereby demonstrating the potential of this host for PHB production from lignocellulose.