Plastics composed of polyethylene are non-biodegradable and are mostly harmful to the environment. Literature studies documented that the extent of microbial degradation of low-density polyethylene (LDPE) seems to be insufficient and the underlying mechanisms of such degradation remain unexplored. In the present study, efforts were given to degrade LDPE by a recently isolated bacteria Enterobacter cloacae AKS7. Scanning electron microscopic (SEM) image, tensile strength, and weight loss analysis confirmed the efficient degradation of LDPE by AKS7. To investigate the mechanism, it was observed that with the progression of time, the extent of microbial colonization got increased considerably over the LDPE surface. It was also observed that the organism (AKS7) gradually increased the secretion of extracellular polymeric substances (EPS) suggesting the formation of efficient biofilm over the LDPE surface. Furthermore, to comprehend the role of cell-surface hydrophobicity towards biofilm formation, two mutants of AKS7 were screened that showed a considerable reduction in cell-surface hydrophobicity in contrast to its wild type. The result showed that the mutants revealed compromised LDPE degradation than wild-type cells of AKS7. Further investigation revealed that the mutant cells of AKS7 were incapable of adhering to LDPE in contrast to wild-type cells. Thus, the results demonstrated that the cell-surface hydrophobicity of AKS7 favors the development of microbial biofilm over LDPE that leads to the enhanced degradation of LDPE by AKS7. Therefore, the organism holds the assurance to be considered as a promising bio-remediating agent for the sustainable degradation of polythene-based hazardous waste.

中文翻译：

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阴沟肠杆菌AKS7降解低密度聚乙烯（LDPE）：迈向可持续环境修复的潜在一步

由聚乙烯组成的塑料是不可生物降解的，并且大多对环境有害。文献研究表明，低密度聚乙烯 (LDPE) 的微生物降解程度似乎不够，这种降解的潜在机制仍未探索。在本研究中，最近分离的细菌阴沟肠杆菌 AKS7 致力于降解 LDPE。扫描电子显微镜 (SEM) 图像、拉伸强度和重量损失分析证实了 AKS7 对 LDPE 的有效降解。为了研究该机制，观察到随着时间的推移，微生物定植的程度在 LDPE 表面上显着增加。还观察到生物体 (AKS7) 逐渐增加细胞外聚合物 (EPS) 的分泌，表明在 LDPE 表面形成了有效的生物膜。此外，为了理解细胞表面疏水性对生物膜形成的作用，筛选了两种 AKS7 突变体，与野生型相比，它们显示细胞表面疏水性显着降低。结果表明，与AKS7的野生型细胞相比，突变体显示出受损的LDPE降解。进一步的研究表明，与野生型细胞相比，AKS7 的突变细胞无法粘附在 LDPE 上。因此，结果表明，AKS7 的细胞表面疏水性有利于微生物生物膜的发展，而不是 LDPE，从而导致 AKS7 对 LDPE 的降解增强。所以，