This study aims to investigate the biodegradation potential of a gut bacterial strain, Bacillus cereus AP-01, isolated from Tenebrio molitor larvae fed Styrofoam, focusing on its efficacy in degrading low-density polyethylene (LDPE). The biodegradation process was evaluated through a series of assays, including clear zone assays, biodegradation assays, and planktonic cell growth assessments in mineral salt medium (MSM) over a 28-day incubation period. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were employed to characterize the alterations in LDPE pellets, followed by molecular characterization. Over three months, sterile soil + LDPE pellets were treated with different concentrations of gut bacterial strain. The degradation capabilities were assessed by measuring pH, total microbial counts, carbon dioxide evolution, weight loss, and conducting phase contrast microscopy and mechanical strength tests. Results demonstrated that MSM containing LDPE as a carbon source with gut bacterial strain produced a clear zone and enhanced planktonic cell growth. FTIR analysis revealed the formation of new functional groups in the LDPE, while SEM images displayed surface erosion and cracking, providing visual evidence of biodegradation. Molecular characterization confirmed the strain as Bacillus cereus AP-01 (NCBI Accession Number: OR288218.1). A 10% inoculum concentration of Bacillus cereus AP-01 exhibited increased soil bacterial counts, carbon dioxide evolution, and pH levels, alongside a notable weight loss of 30.3% in LDPE pellets. Mechanical strength assessments indicated substantial reductions in tensile strength (7.81 +/- 0.84 MPa), compression (4.92 +/- 0.53 MPa), hardness (51.96 +/- 5.62 shore D), flexibility (10.62 +/- 1.15 MPa), and impact resistance (14.79 +/- 0.94 J). These findings underscore the biodegradation potential of Bacillus cereus AP-01, presenting a promising strategy for addressing the global LDPE pollution crisis.

The high global production combined with low recycling rates of polystyrene (PS) and low-density polyethylene (LDPE) contributes to the abundance of these commonly used plastics in soil, including as microplastics (MPs). However, the combined effects of MPs and heavy metals, such as arsenic (As) on earthworms are poorly understood. Here, we show that neither PS nor LDPE altered the effects of As on the survival, growth, and reproduction of the earthworm Eisenia fetida. As stress, both alone and in combination with the MPs, induced DNA damage in coelomocytes. In As-exposed earthworms, PS and LDPE increased the accumulation of reactive oxygen species while the activities of the antioxidant enzymes peroxidase, superoxide dismutase, and catalase were significantly lower under combined PS/LDPE + As exposure than under As exposure alone. As stress alone reduced cocoon production and the mRNA level of the reproduction-related gene ANN whereas As combined with PS/LDPE reduced the mRNA levels of CYP450, an enzyme involved in detoxification. Integrated biomarker response analysis revealed that PS/LDPE did not significantly impact the overall ecotoxicological effects of As exposure on earthworms. This study provides important insights into the potential ecological risks of MPs in heavy-metal-contaminated soil.

This work studied biocomposites based on a blend of low-density polyethylene (LDPE) and the ethylene-vinyl acetate copolymer (EVA), filled with 30 wt.% of cellulosic components (microcrystalline cellulose or wood flour). The LDPE/EVA ratio varied from 0 to 100%. It was shown that the addition of EVA to LDPE increased the elasticity of biocomposites. The elongation at break for filled biocomposites increased from 9% to 317% for microcrystalline cellulose and from 9% to 120% for wood flour (with an increase in the EVA content in the matrix from 0 to 50%). The biodegradability of biocomposites was assessed both in laboratory conditions and in open landfill conditions. The EVA content in the matrix also affects the rate of the biodegradation of biocomposites, with an increase in the proportion of the copolymer in the polymer matrix corresponding to increased rates of biodegradation. Biodegradation was confirmed gravimetrically by weight loss, an X-ray diffraction analysis, and the change in color of the samples after exposition in soil media. The prepared biocomposites have a high potential for implementation due to the optimal combination of consumer properties.

Global plastic pollution is one of the serious issues which create a severe environmental damage. Microbial biodegradation is an eco-friendly method to overcome the plastic pollution issue. The aim of this study is to explore microbes from garbage soil to manage the Low-density Polyethylene (LDPE). Active biodegrading microbes were identified by clear zone method using mineral salt medium with LDPE. Genome sequencing has been performed for LDPE-degrading strains and identified as Bacillus subtilis and Streptomyces labedae. The biodegradation of LDPE was carried out by using selected active strains. The analysis of biodegradation process was carried out by extracellular enzyme assay, cell hydrophobicity and viability of cells with elevated pH produced by B.subtilis and S.labedae. The weight loss percentage of polymer sheets by B.subtilis and S.labedae were 80% and 85% respectively. Major deformities and surface modification on the LDPE sheet were evaluated by the formation of cracks and pits on the surface. The functional groups in the treated sheets were observed by using FTIR analysis. The highest reduction in tensile strength was observed. The GC-MS analysis revealed the presence of 30 new compounds during the biodegradation. It evolved CO2 of 5.32 g/l with S. labedae and 4.55 g/l with B.subtilis. Phytotoxicity of LDPE degraded byproduct showed a positive growth rate of 97.8 +/- 0.836% in Trigonella foenum seed. Then the cytotoxicity study revealed that it was non-toxic to L292 cell lines. Both strains have the ability to consume and reduce the LDPE film. These organisms are the promising resources to manage the LDPE and offers an ecofriendly solution to solve global plastic pollution. Hence the achieved research information could be applied at a large scale for degrading various plastic materials.