“VALORIZING LIGNOCELLULOSIC BIOMASS FOR SUSTAINABLE PHA PRODUCTION: A PROCESS OPTIMIZATION STUDY WITH PRIESTIA MEGATERIUM”

Abstract

The accumulation of synthetic plastic waste has accelerated the demand for eco-friendly alternatives like Polyhydroxyalkanoates (PHAs). However, the high production cost of PHAs remains a major bottleneck for commercialization. This study investigates the bioconversion of affordable and abundant lignocellulosic waste into high-value PHAs using the bacterial strain Priestia megaterium. To maximize biopolymer yield, a systematic process optimization was conducted during controlled batch fermentation. Various lignocellulosic materials were screened as primary carbon sources, alongside the optimization of critical process parameters, including carbon source concentration, nitrogen sources, pH, and culture temperature. Following optimization, the accumulated PHA was harvested from the final batch culture and subjected to detailed molecular-level characterization. The chemical structure, functional groups, and thermal stability of the extracted biopolymer were comprehensively verified using Fourier Transform Infrared (FTIR) Spectroscopy and Nuclear Magnetic Resonance (NMR) analysis. The results demonstrate that Priestia megaterium effectively metabolizes optimized lignocellulosic residues, yielding high-quality PHAs with favorable physicochemical and thermal properties. This research highlights a sustainable, green biorefinery approach to valorizing agro-industrial residues, offering a viable pathway for the cost-effective production of biodegradable biopolymers.