Optimization of polyhydroxyalkanoate biopolymer production from lignocellulosic wood waste using statistical experimental designs

), incubated at 120 °C for 1 h, and filtered to yield a hydrolysate containing approximately ~ 36 mg/mL total reducing sugars (DNS assay). The hydrolysate served as the carbon source in bioprocess optimization (optimal carbon concentration: 2.50%, equivalent to 25 g/L). Potential PHA-producing isolates were screened using Nile Blue and Sudan Black staining. The most efficient producer, Klebsiella pneumoniae strain DSM 30,104 (MK2023), confirmed through 16 S rRNA sequencing, demonstrated notable PHA accumulation. Process parameters-including carbon and nitrogen concentrations and Temperature-were optimized through Plackett-Burman Design (PBD) followed by Response Surface Methodology (RSM) using a face-centered central composite design. Optimal production was achieved at 2.50% carbon, 0.105% nitrogen, and 34 °C, yielding 5.7 mg/mL PHA after 72 h with 10% (v/v) inoculum. UV-Vis and FTIR analyses confirmed the polymer's identity as polyhydroxybutyrate (PHB). The study highlights wood waste as a viable, low-cost substrate for PHA synthesis, promoting sustainable biopolymer production while advancing circular bioeconomy practices.