High oxygen barrier packaging materials from protein-rich single-celled organisms.

Fossil-based packaging materials pose significant environmental challenges due to their persistence and carbon footprint, resulting in pollution and long-term climate change. Here we develop bioplastic packaging alternatives (films and trays) from protein-rich microbial biomass with glycerol as the plasticizer. The microbial biomass demonstrated excellent film-forming properties through compression molding, and the final materials exhibited good mechanical properties and excellent gas barrier properties - an average oxygen permeability coefficient of 0.33 cm³mm m^-2 day^-1 atm^-1 at 50% relative humidity and 23 °C. The oxygen barrier properties highlight these microbial biomass materials as a promising, sustainable alternative to fossil-based synthetic films like EVOH, which are widely used in multilayer food packaging. Beyond offering a microplastic-free solution, the protein-rich materials present an opportunity to mitigate microplastic pollution at the end of their lifecycle. The current results position bioplastics based on microbial biomass as a critical step forward in addressing environmental sustainability challenges with current commercial packaging materials.