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 application of novel insect proteins as future food resources in the food field has attracted more and more attention. In this study, a biodegradable antibacterial food packaging material with beneficial mechanical properties was developed using Tenebrio molitor larvae protein (TMP), chitosan (CS) and propolis ethanol extract (PEE) as raw materials. PEE was uniformly dispersed in the film matrix and the composite films showed excellent homogeneity and compatibility. There are strong intermolecular hydrogen bond interactions between CS, TMP, and PEE in the films, which exhibit the structure characteristics of amorphous materials. Compared with CS/TMP film, the addition of 3 % PEE significantly enhanced the elongation at break (34.23 %), water vapor barrier property (22.94 %), thermal stability (45.84 %), surface hydrophobicity (20.25 %), and biodegradability of the composite film. The composite film has strong antioxidant and antimicrobial properties, which were enhanced with the increase of PEE content. These biodegradable films offer an eco-friendly end-of-life option when buried in soil. Composite films can effectively delay the spoilage of strawberries and extend the shelf life of strawberries. Biodegradable active packaging film developed with insect protein and chitosan can be used as a substitute for petroleum-based packaging materials, and has broad application prospects in the field of fruits preservation.

Tenebrio molitor L., also known as the mealworm, is a polyphagous insect pest that infests various stored grains worldwide. Both the adult and larval stages can cause significant damage to stored grains. The present study focused on isolating entomopathogenic fungi from an infected larval cadaver under environmental conditions. Fungal pathogenicity was tested on T. molitor larvae and pupae for 12 days. Entomopathogenic fungi were identified using biotechnological methods based on their morphology and the sequence of their nuclear ribosomal internal transcribed spacer (ITS). The results of the insecticidal activity indicate that the virulence of fungi varies between the larval and pupal stages. In comparison to the larval stage, the pupal stage is highly susceptible to Metarhizium rileyi, exhibiting 100% mortality rates after 12 days (lethal concentration 50 [LC50] = 7.8 x 10(6) and lethal concentration 90 (LC90) = 2.1 x 10(13) conidia/mL), whereas larvae showed 92% mortality rates at 12 days posttreatment (LC50 = 1.0 x 10(6) and LC90 = 3.0 x 10(9) conidia/mL). The enzymatic analyses revealed a significant increase in the levels of the insect enzymes superoxide dismutase (4.76-10.5 mg(-1)) and glutathione S-transferase (0.46-6.53 mg(-1)) 3 days after exposure to M. rileyi conidia (1.5 x 10(5) conidia/mL) compared to the control group. The findings clearly show that M. rileyi is an environmentally friendly and effective microbial agent for controlling the larvae and pupae of T. molitor.