Cho Jinwoo, Hermanowicz Slawomir W, Hur Jin
Department of Environment & Energy, Sejong University, Seoul 143-747, Republic of Korea.
ScientificWorldJournal. 2012;2012:751965. doi: 10.1100/2012/751965. Epub 2012 Aug 1.
Effects of experimental conditions on the yield of extracellular polymeric substances (EPSs) extraction by cation exchange resin (CER) were investigated using activated sludge flocs. The experimental variables included resin dose, extraction time, sample dilution, and storage time. An empirical model was proposed to describe the kinetics of extraction process. The extraction yield increases with the extraction time and CER dose until it reached the maximum amount of EPS extraction. The maximum yield of EPS was affected as well by the sample dilution, exhibiting a decreasing trend with increasing dilution factor. It was also found that the amount of EPS extracted from a raw sample depends on the storage time. Once EPS was extracted from the sample, however, the EPS keeps its original quantity under storage at 4°C. Based on the model, the maximum amount of EPS extraction and yield rate could be estimated for different conditions. Comparing the model parameters allows one to quantitatively compare the extraction efficiencies under various extracting conditions. Based on the results, we recommend the original sample should be diluted with the volume ratio of above 1:2 and a raw sample should be treated quickly to prevent the reduction of sample homogeneity and original integrity.
利用活性污泥絮体研究了实验条件对阳离子交换树脂（CER）提取细胞外聚合物（EPS）产率的影响。实验变量包括树脂用量、提取时间、样品稀释度和储存时间。提出了一个经验模型来描述提取过程的动力学。提取产率随提取时间和CER用量的增加而增加，直至达到EPS提取的最大量。EPS的最大产率也受样品稀释度的影响，随着稀释倍数的增加呈下降趋势。还发现从原始样品中提取的EPS量取决于储存时间。然而，一旦从样品中提取出EPS，在4℃储存时EPS的量保持不变。基于该模型，可以估计不同条件下EPS的最大提取量和产率。比较模型参数可以定量比较各种提取条件下的提取效率。根据结果，我们建议原始样品应以高于1:2的体积比进行稀释，并且应快速处理原始样品以防止样品均匀性和原始完整性降低。
