Optimized biochemical depolymerization of plastics from surgical face masks

The plastic component of surgical masks containing polypropylene is posing an environmental threat owing to the overuse of masks with non-biodegradable layers all over the world. The non-biodegradable layer of masks can pose serious environmental problems. There are a few reported chemical, enzymatic, and microbial-based methods known to depolymerize plastics; however, these individual processes may be slow. There is a possibility that chemicals may work together with enzymes and microbes and act as catalysts for depolymerization. Hence, we hypothesized that chemicals, enzymes, and microbes may act synergistically to degrade plastic at a higher speed. To evaluate the main and interactive effects of processes meant for the degradation of plastics, we tested the effects of enzymes, microbes, and zinc oxide on the degradation of plastics in a 1.5 L bioreactor and studied the synergy between these three processes using a two-level, three-variable factorial design. The results indicated a significant interactive and synergistic effect between ZnO and the microbial mix, which could accelerate the depolymerization reaction. These experiments helped us to conclude that depolymerization of polypropylene can be done prior to its disposal to the environment using a combination of chemical and microbial mix.