A virtuous multi-step biorefinery platform to convert urban biowaste into valuable molecules, not disregarding renewable energy and digestate production. The strategy is based on the integration of a thermal pretreatment capable of significantly increasing the fraction of fermentable organic carbon, in order to furthermore change the status of the feedstock to become more suitable for production of a) high-value bio-based molecules, b) biomethane and c) hygienized digestate to be recycled as biofertilizer. The liquid fraction, rich of extracted sugars, will be fermented into marketable fatty acids as short-chain-carboxylates having high potential to be biologically upgraded (to caproic acid). The separated solid fraction is transferred to anaerobic digestion. The potential economic value that could be derived is to mitigate the problem of steeply rising landfill costs; to receive revenues from sales of the products, and subsidies for renewable energy. Caproic acid, with a market value of 2000 USD/tonn is an important industrial chemical for several industrial applications including antimicrobial agent.
Sustainable waste management is the main area where further improvements are needed to unlock new economic opportunities, improve biomaterials supply to industries, create jobs and consolidate the EU leadership in the green technologies sector. The innovative Platform is designed to be integrated into existing production systems, acting as a biorefinery where organic waste are biologically converted into bio-based chemicals, currently derived from petroleum, producing in parallel biogas and high quality compost. The economic advantages of these biotechnological processes with respect to the conventional ones are: 1) organic waste is used as feedstock (very little or even negative cost); 2) do not need catalysts as heavy metals; 3) do not need sterilization costs because of the thermal pretreatment; 4) do not use any genetically modified organisms, since work with only naturally occurring organisms. The challenge is to reduce costs and improve sustainability while making it possible to achieve of sufficiently high yields in the targeted product. Compost, black gold for farmers, will restore soil fertility, prevent plant disease and desertification.