Environmental attributes of fungal-like adhesive materials and future directions for bioinspired manufacturing

Abstract

This study evaluates the environmental impact of fungal-like adhesive materials (FLAMs), which are at the forefront of bioinspired manufacturing for sustainability and are thus well-poised to enable a circular economy because they can be sourced, manufactured, and degraded in almost any ecosystem, including urban environments. The main constituents of FLAMs (i.e., cellulose and chitin) are ubiquitous and available from diverse material sources, and the environmental impact of current production practices would vary depending on material sourcing. Here, cradle-to-gate life-cycle assessments were performed on four scenarios with different material sources to. provide insights into the environmental impact of the technology in its current state and identify critical areas to prioritize in future developments. Key contributors were material transportation and chemical use (i.e., sodium hydroxide), which significantly improved when FLAM production was based on regional suppliers and reduced the import distances of raw materials. Next, it was determined that cellulose selection must be based on regionally available pulping technology because using virgin or recycled cellulose fibers has a negligible impact on FLAM production. Finally, it was found that the use of locally produced chitosan from black soldier flies is a positive step toward regionalization and shorter distances. However, as a process performed at a lab scale, it requires the adoption of novel and more efficient biomass fractionation, such as those being implemented for other farmed arthropods (e.g., shrimp). Relative to similar materials, such as rigid polyurethane foam, lower impacts were observed in more than half the environmental indicators, positioning FLAMs in their current state as a more sustainable alternative, even without considering their unassisted compostability. The direction of future developments recommended here resonates with the research efforts on bioinspired manufacturing based on the convergence of ubiquitous resources, regional production, and optimized methods of extraction and fractionation of biomass resources, which we believe should be prioritized. The potential impact of the ongoing and proposed research efforts highlights the unique opportunity enabled by FLAMs and bioinspired manufacturing to minimize transportation and maximize the ecological integration of materials, which in turn present a unique prospect for the development of sustainable manufacturing.