From fruit and vegetable waste to degradable bioplastic films and advanced materials: A review

Productions of plastic products are reaching new heights every year, which brings serious environmental pollution, as non-degradable plastics threaten animals, plants even humans. The expansion of bioplastics has benefited from emerging biotechnologies, but high costs and poor performance still limit their application. Meanwhile, global food production is gradually increasing, causing concerns about the disposal of food waste, the best example being fruit and vegetable wastes (FVW). A feasible option is to establish an FVW refining platform to introduce the waste stream into the production of biodegradable bio-based plastics. In this manuscript, recent strategies for recycling and processing FVW to precursors for bioplastics were reviewed. Providing microbial fermentation with FVW as nutritional supplements instead of overpriced pure substrates (e.g. glucose) is an ideal option, before fermentation, FVW needs to be pretreated to release microbially available monomers or polymers. Bioblocks with high compressive strength are produced by co-extruded mycelium and substrate. Valuable components contained in FVW (lignocellulose, starch, protein, pectin, lipids and polyphenols) are incorporated into new eco-friendly materials for bioplastic production. The retention of bioactive substances in FVW during processing is beneficial to expand the functionalities of bioplastics such as antimicrobial, antioxidant and visualized pH response. At the end of the life cycle, degradable bioplastics degrade aerobically or anaerobically digested to produce methane. Novel bioplastics from FVW show great potential, such as plant fertilizers, smart packaging, biomedical devices, sensors, supercapacitors, electronic devices, sustaining environmental stress reduction, and promoting bioeconomic cycles.