Re-Waste: promoting agriculture sustainability by recycling wet-organic waste

In the EU, an estimated 20% of the total food produced is lost or wasted. Food waste is a rich in highly valuable biomolecules: phytochemicals such as pigments, phenolic bioactive compounds, oligosaccharins and minerals able to cause changes in crop important physiological processes. The purpose of the current study is to exploit waste by-product to develop a sustainable strategy for crop plant growth, development and resilience to (a)biotic stresses. We, thus, conducted agronomic trials on two model species for agriculture (wheat and tomato) by using agro-food waste, i.e. orange peel and crustacean shells, that was compacted and dehydrated, and the solid residue (SR) obtained at the end of the compaction cycle was directly added to growth substrate. Different morphophysiological parameters (e.g. SPAD Index, chlorophyll fluorescence, stomatal conductance and plants biomass) were positively influenced by the addition of low doses of both SRs hinting that they may be effective in regulating plant physiology. These SRs represent a potential reservoir of bioactive products, including oligosaccharins, such as chitooligosaccharides - derived from partial degradation of chitin/chitosan - and oligogalacturonides - derived from partial degradation of homogalacturonan, a major pectin component of the plant cell wall - both potential alternative to traditional agrochemicals. Moreover, SRs could correct the hydrogeological and breathable characteristics of soils as well as determine soil remediation effects by positively affecting plant-microbiome relationships, optimizing interactions with beneficial microorganisms. We propose here a novel, safe and sustainable strategy based on a model that promotes circular economy by recycling wet-organic waste, replacing chemical fertilizers, reducing pollution and high management costs by cutting off waste collection, transport, and delivery.