Optimization of PHBV Synthesis Using Acetate as a Carbon Source by Paracoccus shandongensis wg2 via Response Surface Methodology.

This study investigated the potential of Paracoccus shandongensis wg2, a strain isolated from propylene oxide (PO) saponification wastewater-activated sludge, for synthesizing polyhydroxybutyrate-co-hydroxyvalerate (PHBV) using sodium acetate as the sole carbon source. The synthesis of PHBV was confirmed by nuclear magnetic resonance (NMR) analysis, eliminating the need for 3-hydroxyvalerate (3-HV) precursors and highlighting the strain's potential for significantly reducing production costs. Initial optimization using a single-factor approach was followed by a response surface methodology employing Plackett-Burman and Box-Behnken experimental designs. The optimal conditions were determined as follows: sodium acetate concentration of 7.5 g/L, fermentation temperature of 29 °C, and loading volume of 120 mL, demonstrating the higher PHBV yield of strain wg2 (41.19%), representing an 11.87% enhancement compared to the unoptimized conditions. The wg2 based synthesized PHBV demonstrated high thermal stability and remarkable physical and mechanical properties, indicating significant potential in thermoplastic applications.