Carol D, Karpagam S, Kingsley S J, Vincent S
Department of Plant Biology and Biotechnology, Loyola College Chennai 600 034, India.
Indian J Exp Biol. 2012 Jul;50(7):497-501.
The biodegradation of spent saline bottles, a low density polyethylene product (LDPE) by two selected Arthrobacter sp. under in vitro conditions is reported. Chemical and UV pretreatment play a vital role in enhancing the rate of biodegradation. Treated LDPE film exhibits a higher weight loss and density when compared to untreated films. Arthrobacter oxydans and Arthrobacter globiformis grew better in medium containing pretreated film than in medium containing untreated film. The decrease in density and weight loss of LDPE was also more for pretreated film when compared to untreated film indicating the affect of abiotic treatment on mechanical properties of LDPE. The decrease in the absorbance corresponding to carbonyl groups and double bonds that were generated during pretreatment suggest that some of the double bonds were cut by Arthrobacter species. Since Arthrobacter sp. are capable of degrading urea, splitting of urea group were also seen in FTIR spectrum indicating the evidence of biodegradation after microbial incubation. The results indicated that biodegradation rate could be enhanced by exposing LDPE to calcium stearate (a pro-oxidant) which acts as an initiator for the oxidation of the polymers leading to a decrease of molecular weight and formation of hydrophilic group. Therefore, the initial step for biodegradation of many inert polymers depends on a photo-oxidation of those polymers. The application in sufficient details with improved procedures utilizing recombinant microorganism with polymer degradation capacity can lead to a better plastic waste management in biomedical field. The present plastic disposal trend of waste accumulation can be minimized with this promising eco-friendly technique.
报道了两种选定的节杆菌属细菌在体外条件下对废弃盐瓶(一种低密度聚乙烯产品,LDPE)的生物降解情况。化学和紫外线预处理在提高生物降解速率方面起着至关重要的作用。与未处理的薄膜相比,经处理的LDPE薄膜表现出更高的重量损失和密度降低。氧化节杆菌和球形节杆菌在含有预处理薄膜的培养基中比在含有未处理薄膜的培养基中生长得更好。与未处理薄膜相比,预处理薄膜的LDPE密度降低和重量损失也更多,这表明非生物处理对LDPE机械性能的影响。预处理过程中产生的羰基和双键对应的吸光度降低表明,一些双键被节杆菌属细菌切断。由于节杆菌属细菌能够降解尿素,傅里叶变换红外光谱中也出现了尿素基团的分裂,这表明微生物培养后有生物降解的迹象。结果表明,将LDPE暴露于硬脂酸钙(一种促氧化剂)可以提高生物降解速率,硬脂酸钙作为聚合物氧化的引发剂,导致分子量降低和亲水基团的形成。因此,许多惰性聚合物生物降解的初始步骤取决于这些聚合物的光氧化。利用具有聚合物降解能力的重组微生物,以足够详细的改进程序进行应用,可以在生物医学领域实现更好的塑料废物管理。这种有前景的环保技术可以最大限度地减少目前塑料废物堆积的处理趋势。