Assessment of Fungal Decomposition Strategies as a Step Towards the Development of Sustainable Pressure Sensitive Adhesives

Water-based pressure-sensitive adhesives (PSAs) are widely used for different applications due to their cost and convenience. However, their synthesis relies on petroleum-based acrylic monomers, which negatively affects their biodegradability and recyclability. Hybrid acrylic polymers combining acrylic monomers and acrylate-functionalized lactide-based macromonomers could help solve this issue. Recently, we reported on the remarkable biodegradability of these hybrid PSAs in their latex format when using fungal treatments. In this study, we focused on the degradation of dried PSA films, a prevalent application format in commercial settings, by utilizing fungal consortia and solid-state fermentation. Our findings indicated that the type of fungal treatment, carbon source provided, and substrate thickness significantly affected biodegradation rates. The co-culture of Pestalotiopsis microspora and Trametes versicolor demonstrated particularly promising results, achieving degradation rates exceeding 50%, notably, when utilizing wheat bran as a carbon source. Moreover, the renewal of culture media and inoculum further amplified PSA biodegradation. These results underscore the potential of fungal consortia in solid-state cultures to substantially enhance the biodegradation of hybrid acrylic PSA films, offering insights for the design of more sustainable adhesive bio-based products and finally leading to an environmentally responsible end of the PSAs lifecycle.