The circularity of potential bio-textile production routes: Comparing life cycle impacts of bio-based materials used within the manufacturing of selected leather substitutes

Nowadays the fashion industry faces increasing pressures to reduce the environmental impacts associated to the production of leather-based fashion products, particularly considering issues regarding public acceptance due to animal welfare standards and due to the toxicity of tanning chemicals. An alternative solution facilitated by the bio-textiles industry is the introduction of vegan and bio-based leather substitutes for the production of shoes, handbags, clothing’s and upholstery i.e. on the basis of natural fibres, bio-based polymers, microbial cellulose and fungal mycelium composite products. Nonetheless, also these bio-based leather products cause negative environmental impacts i.e. related to land-use change and intensification, to water use and to energy use in polymer manufacturing. For further impact reduction and designing environmentally most sound solutions, design of leather substitute products should integrate best-practice interventions for increased circularity along the full product life cycles from fibre feedstock provisioning to polymer production and end-of-life recyclability and degradability. This study evaluated the current best practice scenarios for impact reduction when implementing circular design strategies in the production of bio-based fashion materials. Three case studies of alternative leather substitutes were considered, including respectively two sub-scenarios in a comparative Life Cycle Impact Assessment. Results for the aggregated single score using the Environmental footprint approach showed that principles of circularity (e.g. the feedstock type and by-product recovery for fiber and sugar feedstocks) have an influence of 65% between the best and worst performer in mitigating environmental impacts. Furthermore, enhancing the product durability of the leather substitutes against the temporal product replacement benchmark of animal leather would have an influence of 25–70% in mitigating impacts concerning water scarcity and climate change. The most important conclusion of this work is that alternative leather substitutes can contribute to relative environmental advantages in impact reduction in 8–14 impact categories, but only as long as the material substitution is coupled with less frequent product replacement and preferably also low impact coating systems and impregnation agents.