Life Cycle Assessment (LCA) of Bioplastics Production from Lignocellulosic Waste (Study Case: PLA and PHB)

Life cycle assessment of a technology is the key to technological development in the context of sustainable development. Orchard waste has been identified as a potential source of bioplastics. The objective of this study was to conduct a life cycle assessment of two specific bioplastic materials, namely, L-polylactic acid (PLA) and poly(3-hydroxybutyrate) (PHB). Bioplastics, such as PLA acid and PHB, can be used as alternatives to conventional plastics due to their biodegradability and non-toxicity, both of which have the potential to replace conventional petroleum-based plastics. Polylactic acid was synthesized from orchard waste in a series of stages, including biomass processing, pretreatment for carbohydrate extraction, simultaneous saccharification and fermentation (SSF), and microwave polymerization. PHB, another biodegradable polymer, is produced by microorganisms through the fermentation of sugars obtained from the same biomass. Applied LCAs show that for PLA production, the stages having the greatest environmental impact are biomass processing, pretreatment, and the SSF process, and for PHB production, very energy-intensive stages significantly contributing to the environmental impacts are biomass processing and pretreatment stages. For both PLA and PHB, the initial stages of biomass processing and pretreatment are the most energy-intensive and significant contributors to CO₂ emissions.