Application of thermo-separating aqueous two-phase system in extractive bioconversion of polyhydroxyalkanoates by Cupriavidus necator H16

•Extractive bioconversion of PHAs using thermoseparating ATPS proved feasible.•High yield of PHB is achieved through culture optimization.•Achieved PHB yield and purification factor was 97.6% and 1.36 fold, respectively.•Scale-up can be reliably predicted from the experimental data. Polyhydroxyalkanoates (PHAs), a family of biodegradable and renewable biopolymers show a huge potential as an alternative to conventional plastics. Extractive bioconversion (in situ product recovery) is a technique that integrates upstream fermentation and downstream purification. In this study, extractive bioconversion of PHAs from Cupriavidus necator H16 was performed via a thermo-separating aqueous two-phase system to reduce the cost and environmental impacts of PHAs production. Key operating parameters, such as polymer concentration, temperature, and pH, were optimized. The strategy achieved a yield and PF of 97.6% and 1.36-fold, respectively at 5% EOPO 3900 concentration, 30 °C fermentation temperature and pH 6. The PHAs production process was also successfully scaled up in a 2 L bioreactor. To the best of our knowledge, this is the first report on extractive fermentation of PHAs from Cupriavidus necator utilizing a thermo-separation system to achieve a better productivity and purity of the target product.