Biodegradation of polyethylene terephthalate (PET) plastics using a combination of Aspergillus niger and Trichoderma harzianum

Abstract

Plastic is a synthetic organic polymer widely used across various industries, yet its waste contributes significantly to environmental pollution. Polyethylene terephthalate (PET) is one of the most common types of plastic, known for its resistance to degradation, which poses significant environmental risks. This study aimed to evaluate the biodegradation potential of a combination of Aspergillus niger and Trichoderma harzianum fungi on PET. The fungi were isolated using potato dextrose agar (PDA) and incubated in potato dextrose broth (PDB) to establish growth curves and prepare inocula. PET samples were sterilized and subjected to biodegradation tests in minimal salt medium (MSM) with 10% and 15% fungal inoculations over 30 days. The results revealed significant physical alterations in PET, including color changes, surface curvature, and scratches. Weight loss measurements indicated that the combination of A. niger and T. harzianum achieved 1.80% degradation with 10% inoculation and 1.13% with 15% inoculation. Furthermore, Fourier-transform infrared spectroscopy (FTIR) analysis demonstrated significant changes in functional groups, including the formation of new hydroxyl, carboxylic acid, and alkene groups, indicating polymer chain breakdown. This study highlights the novel application of fungal consortia in PET biodegradation and underscores its potential as a sustainable approach for managing PET plastic waste.