Tribedi Prosun, Dey Samrat
Department of Microbiology, Assam Don Bosco University, Tapesia, Sonapur, Assam, 782402, India.
Department of Biotechnology, The Neotia University, Sarisha, West Bengal, 743363, India.
Environ Monit Assess. 2017 Nov 9;189(12):624. doi: 10.1007/s10661-017-6351-2.
Polyethylene represents nearly 64% of all the synthetic plastics produced and are mainly used for domestic and industrial applications. Their extensive use poses a serious environmental threat because of their non-biodegradable nature. Among all the polyethylene remediation strategies, in situ bioremediation happens to be the safest and efficient one. In the current study, efforts had been given to compare the extent of LDPE degradation under UV-treated and UV-untreated conditions by soil microcosm. Landfill soil was collected and UV-treated and UV-untreated LDPE were added separately to the soil following incubation under similar conditions. Electron microscopic images as well as the weight loss and the tensile strength results clearly revealed that UV-treated LDPE showed better degradation than the non-treated ones in soil. To elucidate the mechanism of this enhanced biodegradation, the bond spectra of differentially treated LDPE were analyzed by FTIR. The results obtained from bond spectra studies revealed that UV treatment increases both carbonyl and terminal double-bond index of the LDPE, thereby making it highly susceptible for microbial degradation. Moreover, incubation of UV-treated LDPE with soil favors better adherence of metabolically active and significantly higher number of microorganisms on it. Taken together, all these results demonstrate the higher microbial association and their better metabolic potential to the UV-treated LDPE that lead to enhanced degradation of the LDPE by the soil microorganisms.
聚乙烯占所有合成塑料产量的近64%，主要用于家庭和工业应用。由于其不可生物降解的特性，它们的广泛使用对环境构成了严重威胁。在所有聚乙烯修复策略中，原位生物修复恰好是最安全、最有效的方法。在当前的研究中，通过土壤微观模型比较了紫外线处理和未处理条件下低密度聚乙烯（LDPE）的降解程度。收集了填埋场土壤，并在相似条件下孵育后，分别向土壤中添加了紫外线处理和未处理的LDPE。电子显微镜图像以及重量损失和拉伸强度结果清楚地表明，紫外线处理的LDPE在土壤中的降解效果优于未处理的LDPE。为了阐明这种增强的生物降解机制，通过傅里叶变换红外光谱（FTIR）分析了不同处理的LDPE的键光谱。键光谱研究获得的结果表明，紫外线处理增加了LDPE的羰基和末端双键指数，从而使其极易受到微生物降解。此外，紫外线处理的LDPE与土壤一起孵育有利于代谢活跃且数量明显更多的微生物更好地附着在其上。综上所述，所有这些结果表明，紫外线处理的LDPE与微生物的关联更高，且其具有更好的代谢潜力，这导致土壤微生物对LDPE的降解增强。
