Production of a biopolymer for leather. A life cycle assessment perspective

Abstract The aim of this paper was to develop a biopolymer based on raw materials not originating from petroleum chemistry to reduce the environmental impact. To this end, an acrylic-based retanning product was designed where part of the fossil-based raw materials was replaced with biomass-derived polysaccharides. Life cycle assessment (LCA) of both the new biopolymer and a standard product was conducted to determine the environmental impact caused by each product. The biodegradability of both products was determined by BOD5/COD ratio measurement. Both products were characterized by IR, gel permeation chromatography (GPC), and Carbon-14 content. The new product was experimented as compared to standard fossil-based product, and the main properties of leathers and effluents were assessed. The results showed that fossil-based raw materials can be partially replaced with biomass derivatives while providing the leather with similar organoleptic characteristics. The new biopolymer showed higher biodegradability and better exhaustion (lower COD). LCA allowed concluding that the new biopolymer reduces the environmental impact of 4 of the 19 impact categories analyzed; in particular, the carbon footprint was reduced by 9% vs. the standard acrylic resin. Finally, a sensitivity analysis was performed where the polysaccharide derivative was replaced with a protein derivative. The analysis concluded that the protein-based biopolymer clearly reduced the environmental impact in 16 of the 19 categories studied. In this case, the carbon footprint was reduced by 47%. Therefore, the choice of the biopolymer is critical in this type of products, which may or may not reduce the environmental impact.