• Energy Research

With the aim to fully exploit the by-products obtained after the industrial extraction of starch from sweet potatoes, a cascading approach was developed to extract high-value molecules, such as proteins and pectins, and to valorize the solid fraction, rich in starch and fibrous components. This fraction was used to prepare new biocomposites designed for food packaging applications. The sweet potato residue was added to poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in various amounts up to 40 wt % by melt mixing, without any previous treatment. The composites are semicrystalline materials, characterized by thermal stability up to 260 °C. For the composites containing up to 10 wt % of residue, the tensile strength remains over 30 MPa and the strain stays over 3.2%. A homogeneous dispersion of the sweet potato waste into the bio-polymeric matrix was achieved but, despite the presence of hydrogen bond interactions between the components, a poor interfacial adhesion was detected. Considering the significant percentage of sweet potato waste used, the biocomposites obtained show a low economic and environmental impact, resulting in an interesting bio-alternative to the materials commonly used in the packaging industry. Thus, according to the principles of a circular economy, the preparation of the biocomposites closes the loop of the complete valorization of sweet potato products and by-products.

Currently, multilayer packaging is widely used for the preservation and distribution of food, beverages, pharmaceuticals and other consumable products. However, if packaging materials are excellent in preserving, protecting and extending the useful life of the packaged goods, on the other hand their recycling is very demanding because of multimaterial layers, which cannot be simply separated and reused. Actually the majority of such packaging is either incinerated or bound for landfills. The European project H2020 TERMINUS [1] aims at designing a smart multilayer packaging able to self-delaminate at the end of its life, thus enabling the recycling of the different layers. The delamination strategy involves the use of protected enzymes within the multilayer formulation. After a specific trigger, the enzyme is released and degrades the adhesive anchoring the layers, causing debonding, thus layers can be separated and recycled. In detail, in the present study some enzymes with high degrading activity against some polymeric adhesives were protected, in order to increase their thermal stability and allow their use during the processing of the multilayer. With the successful implementation of TERMINUS project, the expected results will lead to a 15% of improved economy efficiency, 80% reduction of the landfilling rates for multilayer packaging as well as 50% decrease of overall landfilling rates of plastic, along with a 65% decrease in carbon dioxide emissions. [1] TERMINUS has received funding from the European Union’s Horizon 2020 research and innovation programme, under grant agreement number 814400. poster for Ecomondo The Green Technology Expo

AbstractThis study presents a multidisciplinary approach for dealing with the environmental problems related to agro‐industrial coffee residues. The exploitation of these residues allows biomolecules to be obtained from renewable sources and enables the preparation of CO2‐neutral biocomposites, with the advantages of reducing fossil depletion, avoiding climate‐altering emissions, and limiting plastic pollution. Coffee silverskin (CSS), a by‐product deriving from coffee bean roasting, was subjected to different eco‐friendly extraction processes, such as ultrasound‐assisted, CO2‐supercritical, and water‐subcritical extractions to recover caffeine, phytosterols, and polyphenols. The residues remaining after the extractions were further valorized as fillers into biocomposites based on poly(1,4‐butylene succinate) (PBS). Biocomposites (filler content up to 30 wt%) were prepared by melt mixing, and they were characterized in terms of their thermal, mechanical, and morphological performance. The effect of the presence of residues derived from different extraction procedures on the resulting properties of biocomposites was assessed and discussed, and the ultrasound‐assisted treatment was found to leave the CSS residue as the most compatible with the PBS matrix. The results of this study indicate that the proposed bio‐refinery could successfully and fully valorize the CSS agro‐industrial residues, even in its ultimate step, producing biocomposites characterized by low economic and environmental impact; these new materials will be a possible bio‐alternative to the traditional polymers commonly used by the packaging industry.

In recent years, the circular economy and sustainability have gained attention in the food industry aimed at recycling food industrial waste and residues. For example, several plant-based materials are nowadays used in packaging and biofuel production. Among them, by-products and waste from coffee processing constitute a largely available, low cost, good quality resource. Coffee production includes many steps, in which by-products are generated including coffee pulp, coffee husks, silver skin and spent coffee. This review aims to analyze the reasons why coffee waste can be considered as a valuable source in recycling strategies for the sustainable production of bio-based chemicals, materials and fuels. It addresses the most recent advances in monomer, polymer and plastic filler productions and applications based on the development of viable biorefinery technologies. The exploration of strategies to unlock the potential of this biomass for fuel productions is also revised. Coffee by-products valorization is a clear example of waste biorefinery. Future applications in areas such as biomedicine, food packaging and material technology should be taken into consideration. However, further efforts in techno-economic analysis and the assessment of the feasibility of valorization processes on an industrial scale are needed.

Agricultural waste is a huge pool of untapped biomass resources that may even represent economic and environmental burdens. They can be converted into bioenergy and bio-based products by cascading conversion processes, within circular economy, and should be considered residual resources. Major challenges are discussed from a transdisciplinary perspective, focused on Europe situation. Environmental and economic consequences of agricultural residue management chains are difficult to assess due to their complexity, seasonality and regionality. Designing multi-criteria decision support tools, applicable at an early-stage of research, is discussed. Improvement of Anaerobic Digestion (AD), one of the most mature conversion technologies, is discussed from a technological point of view and waste feedstock geographical and seasonal variations. Using agricultural residual resources for producing high-value chemicals is a considerable challenge analysed here, taking into account innovative eco-efficient and cost-effective cascading conversion processes (bio-refinery concept). Moreover, the promotion of agricultural residues-based business is discussed through industrial ecology, to promote synergy, on a local basis, between different agricultural and industrial value chains. Finally, to facilitate a holistic approach and optimise materials and knowledge flows management, the connection of stakeholders is discussed to promote cross-sectorial collaboration and resource exchange at appropriate geographic scales.