Akash Krishnamoorthi, Parthasarathi Rengasamy, Elango Rajavel, Bragadeeswaran Subramanian
Department of Microbiology, Faculty of Agriculture, Annamalai University, Annamalai Nagar, Chidambaram, Tamilnadu, 608002, India.
Department of Soil Science and Agricultural Chemistry, Anbil Dharmalingam Agricultural College and Research Institute, Trichy, Tamilnadu, 620027, India.
Biodegradation. 2025 Jan 7;36(1):12. doi: 10.1007/s10532-024-10107-z.
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.
本研究旨在调查从取食聚苯乙烯泡沫塑料的黄粉虫幼虫中分离出的肠道细菌菌株蜡样芽孢杆菌AP-01的生物降解潜力，重点关注其对低密度聚乙烯（LDPE）的降解效果。通过一系列试验对生物降解过程进行评估，包括透明圈试验、生物降解试验以及在矿物盐培养基（MSM）中为期28天的培养期内对浮游细胞生长的评估。采用傅里叶变换红外光谱（FTIR）和扫描电子显微镜（SEM）对LDPE颗粒的变化进行表征，随后进行分子表征。在三个月的时间里，用不同浓度的肠道细菌菌株处理无菌土壤+LDPE颗粒。通过测量pH值、总微生物数量、二氧化碳释放量、重量损失，并进行相差显微镜观察和机械强度测试来评估降解能力。结果表明，含有LDPE作为碳源并添加肠道细菌菌株的MSM产生了透明圈并促进了浮游细胞生长。FTIR分析揭示了LDPE中新官能团的形成，而SEM图像显示表面侵蚀和开裂，为生物降解提供了直观证据。分子表征证实该菌株为蜡样芽孢杆菌AP-01（NCBI登录号：OR288218.1）。蜡样芽孢杆菌AP-01的10%接种浓度使土壤细菌数量、二氧化碳释放量和pH值增加，同时LDPE颗粒的重量显著损失30.3%。机械强度评估表明，拉伸强度（7.81±0.84MPa）、压缩强度（4.92±0.53MPa）、硬度（51.96±5.62邵氏D）、柔韧性（10.62±1.15MPa）和抗冲击性（14.79±0.94J）大幅降低。这些发现强调了蜡样芽孢杆菌AP-01的生物降解潜力，为解决全球LDPE污染危机提供了一种有前景的策略。
