Biodegradation process of a blend of thermoplastic unripe banana flour - Polyethylene under composting: Identification of the biodegrading agent

Starch-based biodegradable polymers are obtained by incorporating plant-derived polymers into plastics. This blending allows for a reduction in the polymer's resistance to microbial degradation. Assessing biodegradability is a key step in the characterization of newly designed polymers. Composting has been taken into consideration in waste management strategies as an alternative technology for plastic disposal. This study analyzed the biodegradability of an injection-molded plastic material in which thermoplastic unripe banana flour (TPF) acts as a matrix (70%) and metallocene catalyzed polyethylene acts as a reinforcing filler (30%). This plastic was termed 70 TPF, and the structural, physical, and mechanical changes associated with its degradation were analyzed. The characterization of the microorganism that contributes to 70 TPF biodegradation was also performed. After composting, 70 TPF decreased in tensile strength and the TPF moiety in the blend was lost, greatly affecting the microstructure of the sample. Based on these indicators of degradation, this study identified the fungus Mortierella elongata as the microorganism responsible for the degradation of the plastic, a finding that supports the role of fungal communities in the biodegradation of designed materials.