Upgrading agrifood co-products via solid fermentation yields environmental benefits under specific conditions only

Abstract

Solutions towards decoupling food production from arable land are increasingly promoted to alleviate food system's environmental impacts. It includes solid substrate fermentation (SSF), allowing to nutritionally enhance brous co-products. Yet, it remains unclear whether and to which extent SSF valorization pathways really improve environmental performances of agrifood co-products in comparison to current practices. Using a framework which combines process-based consequential life cycle analysis, uncertainty assessment and biomass resource potential estimation, we quantify and qualify implications of SSF nutritional enhancement through six selected case studies. When used to unlock food markets, SSF yields environmental bene ts for all impact categories. When used to unlock feed markets (low-value streams), SSF pathways are preferable options compared to energy valorization for most impacts except climate change. We show that the environmental impacts of novel food and feed are principally dependent on avoided crops and land use change accounting methods, these requiring further and systematic harmonization. Full TextAchieving generalized and signi cant changes of current food system is essential, not only to meet environmental targets, but also to comply with future food demand 1,2 . Therefore, reducing the dependence on crop importations by developing locally sourced commodities and enhancing the decoupling of food production from land are levers to mitigate food system's environmental impacts 3,4 . Among these solutions, "waste-to-nutrition" pathways, transforming organic wastes, residues and coproducts into edible ingredients, are increasingly promoted 5 . In this study, we assess the conditions under which fungal solid substrate fermentation (SSF) can sustainably be used as an alternative valorization option for agrifood co-products.SSF is based on the colonization of a solid substrate by a biological agent which, in the case of feed applications, allows to enhance or even unlock the nutritional value of brous feedstocks, mainly through lignocellulose degradation, proteins concentration and digestibility enhancement [6][7][8][9] . Applied to

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

“…Fungal SSF is mostly applicable to the large set of lignocellulosic agrifood co-products and primary crop residues, while the rest of the waste-to-nutrition options of this group are stream-speci c (depending on input's composition-structure; Javourez et al, 2021). Yet, the nal service supplied by SSF also depends on input's characteristics and range from our-equivalent services to roughage services (Javourez et al, 2022). The direct reintroduction of C3 by-products as food ingredients (offal, etc.)…”

“…First, the pathways should align with the waste management hierarchy pyramid. This implies that the pathways should (i) be based on unavoidable residual streams (under current production pattern), (ii) upgrade current use of the target streams regarding its contribution to food system (Javourez et al, 2022) and (iii) offer substitution of commodities/services associated with relatively important environmental impacts (e.g. proteins).…”

“…Second, when relevant, set-ups variants were de ned. This is because a (co)-product stemming from a speci c technological set-up might provide different services depending on its valorization strategy, hence in uencing the global performances (environmental, economic) of the studied pathway (Javourez et al, 2022). In this work, this essentially applies to human food versus animal feed services (e.g.…”

“…Fertilizing services were focused on N, P and K. These were de ned and modeled in Javourez et al, (2023), with additional information in the SI. Feed services were separated into protein, lipids and carbohydrates services as in Javourez et al, (2022), amended by an additional "roughage" service. The Scandinavian Feed Unit (SFU) was used to quantify the amount of each feed service provided by the novel ingredients formulated through the waste-tonutrition pathways.…”

“…The nutritional enhancement of agrifood co-products through solid fermentation (SSF) was already detailed and corresponding parametric LCI model designed in (Javourez et al, 2022), along with the CF pathways (that is, the direct reuse of feed-grade residual streams in animal diets). The same set-ups for both CF and (fungal-based) SSF were kept for this study, and expanded to integrate the wide set of suitable residual streams.…”