Biorefining of kitchen waste for the targeted production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) through open...

The production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) via the open mixed microbial consortium (MMC) with kitchen waste hydrolysate as feeds offers considerable conveniences; nevertheless, the optimal parameters and the green benefit potentials remain unclear. The domestication process of MMC established that butyrate-type mixed flora exhibited the highest PHBV fermentation efficiency (472 mg·g^-1 TSS). The single-factor optimization of fermentation conditions identified the optimal PHBV concentration (1876.2 mg·L^-1) was achieved in a system utilizing 8.8 g·L^-1 butyric acid as the carbon substrate, with a C/N ratio set at 80, a pH of 7, and 30 °C. Co-substrate culture investigations demonstrated that the butyric-valeric acids combination recorded the highest PHBV accumulation of 2055.1 mg·L^-1, corresponding to a 40.2% proportion of 3-hydroxyvalerate (3 HV). The synthesis of targeted PHBV (3-80% 3 HV) was accomplished through regulating the fractions of butyric and valeric acids. Foremost, the accumulation of 1340.9 mg·L^-1 and 1604.4 mg·L^-1 of PHBV was achieved utilizing stimulated anaerobic fermentation broth and kitchen waste hydrolysate as nutrients, respectively. Carbon footprint analysis revealed a substantial reduction in overall process consumption (34.33 kg CO₂-eq·t^-1). This study presents comprehensive technical parameters for the biomanufacturing of bioproducts derived from organic waste, offering an alternative green waste‑carbon recovery technology.