Synergistic effect of UV, thermal, and chemical treatment on biological degradation of low-density polyethylene (LDPE) by Thermomyces lanuginosus

The present analysis deals with the ability of Thermomyces lanuginosus to degrade pre-treated low-density polyethylene (LDPE). The synergistic effect of UV irradiation, heat, and acid pre-treatments on the biodegradability of the polymer was thoroughly assessed. Oxidative structural modifications such as the appearance of carboxylate and carbonyl groups in LDPE chains were recorded post the UV and heat treatments. Furthermore, the nitric acid treatment incorporated NO2 groups into the polymer matrix. Alterations in the polymer thermal stabilities and surface morphologies after each pre-treatment were analyzed using thermogravimetric analysis and scanning electron microscopy (SEM), respectively. The gravimetric analysis revealed a reduction in the weight of the pre-treated LDPE films by 9.21 ± 0.84% after 1 month of the incubation period with Thermomyces lanuginosus. An increase in the thermal stability, disappearance of the incorporated hydrophilic functional groups, and reduction in the carbon content of the polymer samples post the incubation period further justified the biodegradation process. SEM analysis showed modifications in the morphology and texture patterns in pre-treated LDPE after inoculation with Thermomyces lanuginosus. The findings suggest that Thermomyces lanuginosus could be efficient for the decomposition of pre-treated LDPE under laboratory conditions.