Waste reintroduced in the kitchen: life cycles inventories of representative waste-to-nutrition pathways

Abstract

Waste recovery technologies targeting the formulation of edible ingredients such as insects, microorganisms, or proteins extracts, are increasingly promoted to mitigate global environmental impacts. Yet, many conversion pathways exist, and little is known about the plausibility, the implications, and the environmental relevance of deploying them: a comparative framework is missing. To this end, we reviewed the available data and literature documenting these emerging biorefineries and compiled it into six harmonized life cycle inventory (LCI) models estimating the forecasted performances of 16 representative “waste-to-nutrition” pathways in function of 18 input stream characteristics and 293 process parameters. Illustrated on eleven case studies, the results quantify the untapped potential of transforming waste into novel food and feed, but also precisely document why these are no free lunches by unravelling the intrinsic trade-offs between their energy intensity, their yield and the initial composition-structure of input streams. We show that several scenarios are possible to achieve France’s protein feed autonomy by scaling and combining different waste-to-nutrition pathways, but that each scenario would lead to different implications for the energy system and in terms of biomass mobilization. As provided, the LCI models capture the implications associated with these waste recovery technologies and are ready to support their prospective life cycle assessment.