Innovations in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and nanocomposites for sustainable food packaging via biochemical biorefinery platforms: A comprehensive review

The substantial build-up of non-biodegradable plastic waste from packaging sector not only poses severe environmental threats but also hastens the depletion of natural petroleum-based resources. Presently, poly (3-hydroxybutyrate-co-3-hydroxy valerate) (PHBV), received enormous attention as ideal alternatives for such traditional petroleum-derived plastics based on their biocompatibility and superior mechanical properties. However, high cost of such copolymer, due to expensive nature of feedstock, inefficient microbial processes and unfavorable downstream processing strategies restricts its large-scale commercial feasibility in the packaging sector. This review explores merits and challenges associated with using potent agricultural and industrial waste biomasses as sustainable feedstocks alongside improved fermentation and downstream processing strategies for the biopolymer in terms of biorefinery concept. Despite PHBV's attractive properties, its inherent shortcomings like weak thermal stability, poor mechanical properties, processability difficulty, substantial hydrophobicity and comparatively higher water vapor permeability (WVP) demand the development of its composites based on the application. Based on this fact, the review assessed properties and potential applications of PHBV-based composite materials having natural raw materials, nanomaterials and synthetic biodegradable polymers. Besides, the review also enlightens sustainability, future prospects, and challenges associated with PHBV-based composites in the field of food packaging while considering insights about economic evaluation and life cycle assessment.