Effect of nitrogen availability on the poly-3-D-hydroxybutyrate accumulation by engineered Saccharomyces cerevisiae.

Poly-3-D-hydroxybutyrate (or PHB) is a polyester which can be used in the production of biodegradable plastics from renewable resources. It is naturally produced by several bacteria as a response to nutrient starvation in the excess of a carbon source. The yeast Saccharomyces cerevisiae could be an alternative production host as it offers good inhibitor tolerance towards weak acids and phenolic compounds and does not depolymerize the produced PHB.

Anaerobic poly-3-D-hydroxybutyrate production from xylose in recombinant Saccharomyces cerevisiae using a NADH-dependent acetoacetyl-CoA reductase.

Background: Poly-3-D-hydroxybutyrate (PHB) that is a promising precursor for bioplastic with similar physical properties as polypropylene, is naturally produced by several bacterial species. The bacterial pathway is comprised of the three enzymes β-ketothiolase, acetoacetyl-CoA reductase (AAR) and PHB synthase, which all together convert acetyl-CoA into PHB. Heterologous expression of the pathway genes from Cupriavidus necator has enabled PHB production in the yeast Saccharomyces cerevisiae from glucose as well as from xylose, after introduction of the fungal xylose utilization pathway from Scheffersomyces stipitis including xylose reductase (XR) and xylitol dehydrogenase (XDH).