Exploiting sugar-rich feedstocks for sustainable polyhydroxyalkanoate production

Plastic pollution is an international issue, with petrochemical plastics promoting waste build-up, aquatic ecosystem impairment, and microplastic pollution. Polyhydroxyalkanoates (PHAs) have gained a lot of attention as an alternative material owing to their similar mechanical characteristics to traditional plastics, together with biodegradability and ecological inertness. These bacterial biopolymers, which are polymerized by bacteria like Cupriavidus necator and Bacillus megaterium as intracellular carbon and energy stores, can be made from biotic feedstocks, aligning with circular economy and sustainability objectives. The main limitation to mass adoption is high production price, which is generally determined by substrate cost. Sugar-rich feedstocks such as sugarcane molasses, beet molasses, and corn syrup have the potential to cut costs by 30%–40% relative to glucose-based fermentation. The use of agro-industrial by-products not only reduces raw material expenses but also favours waste valorization as well as local economic advantages. The efficiency of production is greatly influenced by process parameters and feedstock properties, wherein optimization of pH, dissolved oxygen, and carbon-to-nitrogen ratios greatly improves yield and polymer quality. Additionally, PHAs blends and composites with enhanced thermal, mechanical, and barrier properties present suitable solutions for packaging and allied applications. With growing consumer consciousness and regulatory demands, PHAs from sugar feedstocks offer both economic and ecological benefits. Engineered microbial strains and inexpensive downstream processing are future work priorities for scalable and sustainable production. The present review examines the viability of using sugar-rich substrates as economically viable feedstocks to produce PHAs and their role in the development of sustainable bioplastics.