Sustainable bio-compounds for a circular economy: insights from the Life Restart project

The close-to-market Life Restart project, co-financed by the European Union (LIFE Program for the Environment and Climate Action), focuses on recycling agri-food waste to produce biodegradable bio composites within a “green” and circular economy framework ^[1].

The project aims to recover and reuse 75% of a major beer production by-product (brewer's spent grains—BSG), while reducing the consumption of fossil-based polymers by 15% and virgin biopolymers by 35%. This approach promotes the use of bioplastics (bio-derived/bio-degradable) instead of fossil-based alternatives, as well as the re-use of waste products from the agri-food chain, to contribute to the achievement of carbon neutrality and “net zero emissions” by 2050 ^[2].

In this study, bioplastics are mixed with agri-food waste (brewer spent grain, BSG), to create bio-compounds. We evaluated the mechanical performance of various bioplastics (bio-derived and/or biodegradable) to produce bioplastic–waste mixtures ^[3]. This approach transforms waste into a valuable resource within the framework of a circular economy. By incorporating BSG, the process reduces the amount of bioplastic required, lowering production costs, as bioplastics are significantly more expensive than fossil-based plastics.

As part of the project, partners and stakeholders have developed the first prototypes of different objects, with different processing technologies (such as injection molding, extrusion, melt-mixing, 3D printing) by using these bio-compound mixtures. The mechanical tensile performance of some objects made from bioplastic–waste mixtures was analyzed and compared to that of objects formed from pure bioplastic and to that of fossil-based plastics. We focused on plant pots, in particular, as an example object. The results showed that the bio-compounds made from thebioplastic–waste mixtures exhibit good mechanical tensile strength compared to commercial pots, with the additional advantage of their biodegradability ensuring a fully sustainable product life cycle.

Several other physical, mechanical, rheological, and morphological characterizations of the bioplastic–waste mixtures, before and after degradation (photo-degradation and thermo-mechanical degradation), have been studied.