What type of study is this?

This is a Animal Study study (also classified as: In Vitro Study).

August 18, 2025Open Access

Harnessing and Degradation Mechanism of Persistent Polyethylene Waste by Newly Isolated Bacteria from Waxworm and Termite Gut Symbionts

Key Points

LDPE degradation efficiency reached 19.8% after 45 days with Bacillus cereus LDPE-DB2, outperforming Pseudomonas aeruginosa LDPE-DB26 by 8.2%.
Bacillus cereus produced stronger biofilms with 68.3 µg/cm2 protein content, indicating enhanced surface adhesion compared to Pseudomonas aeruginosa's 55.2 µg/cm2.
Molecular weight analysis showed Bacillus cereus caused a 14.8% decrease in weight-averaged molecular weight, leading to effective polymer chain scission.
Analysis identified degradation products like alkanes and alcohols, suggesting the potential for environmentally-friendly waste management practices.

Abstract

Pollution from synthetic polymers, particularly low-density polyethylene (LDPE), poses a significant environmental challenge due to its chemical stability and resistance to degradation. This study investigates an eco-biotechnological approach involving bacterial strains isolated from insect guts—Bacillus cereus LDPE-DB2 (from Achroia grisella) and Pseudomonas aeruginosa LDPE-DB26 (from Coptotermes formosanus)—which demonstrate the ability to degrade LDPE, potentially through the action of lignin-modifying enzymes. These strains exhibited notable biofilm formation, enzymatic activity, and mechanical destabilization of LDPE. LDPE-DB2 exhibited higher LDPE degradation efficiency than LDPE-DB26, achieving a greater weight loss of 19.8% compared with 11.6% after 45 days. LDPE-DB2 also formed denser biofilms (maximum protein content: 68.3 ± 2.3 µg/cm2) compared with LDPE-DB26 (55.2 ± 3.1 µg/cm2), indicating stronger surface adhesion. Additionally, LDPE-DB2 reduced LDPE tensile strength (TS) by 58.3% (from 15.3 MPa to 6.4 ± 0.4 MPa), whereas LDPE-DB26 induced a 43.1% reduction (to 8.7 ± 0.23 MPa). Molecular weight analysis revealed that LDPE-DB2 caused a 14.8% decrease in weight-averaged molecular weight (Mw) and a 59.1% reduction in number-averaged molecular weight (Mn), compared with 5.8% and 32.7%, respectively, for LDPE-DB26. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and gel permeation chromatography (GPC) analyses revealed substantial polymer chain scission and crystallinity disruption. Gas chromatography–mass spectrometry (GC-MS) identified environmentally benign degradation products, including alkanes, alcohols, and carboxylic acids. This study demonstrates a sustainable route to polyethylene biotransformation using insect symbionts and provides insights for scalable, green plastic waste management strategies in line with circular economy goals.

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