Ultrasound-treatment as a promising strategy to develop biodegradable films obtained from mushroom waste biomass

This work reports on the valorisation of discarded mushroom biomass generated in the industry and the waste produced after a 8-glucan extraction process from three different species (Grifola frondosa, Lentinula edodes, and Pleurotus ostreatus) for the production of biobased and biodegradable films. Initially, the composition of the starting material was characterized before film production. The results evidenced no significant compositional differences between the discarded mushrooms, proteins, and 8-glucans being the main components in all vari-eties. In contrast, the residues were mainly composed of carbohydrates (glucans and chitin). The films obtained from the residues presented a very rigid behaviour, with higher elastic modulus (ca. 2-4.5 GPa) and lower elongation values (ca. 1%) compared to their counterparts prepared with the mushroom's dis-cards. The developed films outperformed benchmark biopolymers in terms of barrier properties with the addi-tional advantages that they can be directly produced from fungal biomass (without plasticizers or any other additives) and they proved to be easily disintegrated according to the standard ISO 20200.