Poly(3-hydroxybutyrate) biosynthesis by Cupriavidus necator: A review on waste substrates utilization for a circular economy approach

Cupriavidus necator owes its popularity to the ability to produce large amounts of the polyester poly (3-hydroxybutyric acid), or PHB. During the last decades, C. necator has earnt an increasing interest in the field of biopolymers and bioplastic production. This versatile bacterium can grow both autotrophically on a mixture of gases (e.g. hydrogen, oxygen, and carbon dioxide) and heterotrophically, on a wide range of organic substrates, including waste feedstocks. In anoxic conditions, it can also denitrification by using nitrate as the electron acceptor. The goal of this review is to underline the versatility of C. necator and its ability to produce biopolymers on a wide variety of carbon sources, comparing pure and waste substrates, used in circular economy biobased PHA production. This study analysis highlight the most suitable feeding strategies to reach the highest PHB accumulation, underlying the important role that C. necator could play for next generation biopolymers.