Poly(3-hydroxybutyrate-3-hydroxyvalerate) production from pretreated waste lignocellulosic hydrolysates and acetate co-substrate

The purpose of this study was to explore the potential of producing Poly(3-hydroxybutyrate-3-hydroxyvalerate) (PHBV) by mixed microbial culture (MMC) with lignocellulosic hydrolysates and acetate co-substrate as feedstock. The addition of co-substrate acetate led to the introduction of HV monomer into the polyhydroxyalkanoate (PHA), and the initial mixed sludge suspension (MLSS) increased with the increase of acetate. Almost 1.91-fold increase in the yield of PHA was achieved with limited nitrogen medium (the carbon to nitrogen ratio (C/N) was 33) compared to the normal nitrogen medium (C/N = 20). Limiting nitrogen source and micro alkaline culture environment was more conducive to the accumulation of PHBV. PHA production achieved to the highest value of about 2308.45 mg/L under the condition of optimized technology. Acidovorax was the dominant genus of all bioreactors using co-substrate. Further, utilizing lignocellulosic hydrolysate and acetate co-substrate as feedstock in mixed microbial culture was a promising approach in a low-cost large-scale PHA production.