Biodegradation of Low Density Polyethylene by the Fungus Cladosporium sp. Recovered from a Landfill Site

Abstract

Low density polyethylene (LDPE) has been widely used commercially for decades; however, as a non-degradable material, its continuous accumulation has contributed to serious environmental issues. A fungal strain, Cladosporium sp. CPEF-6 exhibiting a significant growth advantage on MSM-LDPE (minimal salt medium), was isolated and selected for biodegradation analysis. LDPE biodegradation was analyzed by weight loss percent, change in pH during fungal growth, environmental scanning electron microscopy (ESEM), and Fourier transformed infrared spectroscopy (FTIR). Inoculation with the strain Cladosporium sp. CPEF-6 resulted in a 0.30 ± 0.06% decrease in the weight of untreated LDPE (U-LDPE). After heat treatment (T-LDPE), the weight loss of LDPE increased significantly and reached 0.43 ± 0.01% after 30 days of culture. The pH of the medium was measured during LDPE degradation to assess the environmental changes caused by enzymes and organic acids secreted by the fungus. The fungal degradation of LDPE sheets was characterized by ESEM analysis of topographical alterations, such as cracks, pits, voids, and roughness. FTIR analysis of U-LDPE and T-LDPE revealed the appearance of novel functional groups associated with hydrocarbon biodegradation as well as changes in the polymer carbon chain, confirming the depolymerization of LDPE. This is the first report demonstrating the capacity of Cladosporium sp. to degrade LDPE, with the expectation that this finding can be used to ameliorate the negative impact of plastics on the environment.

Optimizing Eco-Friendly Degradation of Polyvinyl Chloride (PVC) Plastic Using Environmental Strains of Malassezia Species and Aspergillus fumigatus

“…SEM micrographs revealed the presence of erosions and cracks in PVC films treated with fungi, in contrast to control untreated PVC strips. These observations are consistent with the results from several previous studies, as they can be attributed to the colonization of fungal strips with fungal strains and the formation of biofilms [43][44][45][46][47].…”

“…The higher reduction in Dsouza's study may be due to the use of a mixture of three fungal strains, an extended incubation period and the use of enriched growth media (PDA). In contrast, a lower weight reduction (0.3% ± 0.06%) was observed for LDPE treated with fungi recovered from landfill sites [47].…”

Mycodegradation of low-density polyethylene by Cladosporium sphaerospermum, isolated from platisphere

“…LDPE degradation by Trichoderma viride , Paecilomyces varioti , Aureobasidium pullulans were also reported 3 , 4 . Gong et al 39 reported that heat treatment followed by Cephalosporium sp. treatment result in weight loss of LDPE in 30 days.…”