Biotransformation of starch-based wastewater into bioplastics: Optimization of poly(3-hydroxybutyrate) production by Cupriavidus necator DSM 545 using potato wastewater hydrolysate

Biodegradable biopolymers, such as polyhydroxyalkanoates (PHAs), have emerged as an alternative to petrochemical-based plastics. The present work explores the production of PHAs based on the biotransformation of potato processing wastewater and addresses two different strategies for PHA recovery. To this end, culture conditions for PHA synthesis by Cupriavidus necator DSM 545 were optimized on a laboratory scale using a response surface methodology-based experimental design. Optimal conditions rendered a PHB, poly(3hydroxybutyrate), accumulation of 83.74 +/- 2.37 % (5.1 +/- 0.2 gL-1), a 1.4-fold increase compared to the initial conditions. Moreover, polymer extraction with non-halogenated agent improved PHB recovery compared to chloroform method (PHB yield up to 78.78 +/- 0.57 %), while maintaining PHB purity. (99.83 +/- 4.95 %). Overall, the present work demonstrated the potential valorization of starch-based wastewater by biotransformation into PHBs, a high value-added product, and showed that recovery approaches more eco-friendly than the traditional treatments could be applied to PHB recovery to some extent.

Automated summary

This study explores the production and recovery of PHAs from potato processing wastewater. The optimal culture conditions for PHA synthesis by Cupriavidus necator DSM 545 were determined, resulting in a significant increase in PHB accumulation. In addition, a non-halogenated agent was found to be more effective in PHB recovery compared to the traditional chloroform method.