采用高速离心法、EDTA法、阳离子交换树脂法(CER)、甲醛法和甲醛+NaOH法提取普通活性污泥和好氧颗粒污泥的胞外多聚物(EPS),结合三维荧光光谱对五种方法进行评价,并对EPS中的成分进行分析.结果表明,5个EPS的三维荧光光谱峰值中,2个是类蛋白峰,2个是类富里酸峰,1个是类腐殖酸峰.匀浆对好氧颗粒污泥EPS的提取必不可少.甲醛严重干扰核酸的化学测定.透析前后的EPS提取液均应作为分析对象.单纯高速离心法无法有效提取EPS.CER法不容易造成细胞破壁,是一种比较有效的方法.虽然甲醛+NaOH法对EPS的提取量最大,但对细胞的破壁程度也最大.EDTA会导致溶胞,并严重污染EPS.甲醛+NaOH法和EDTA法都会严重干扰胞外蛋白的三维荧光光谱分析.
The efficiency of five extracellular polymeric substances (EPS) extraction methods was compared on normal activated sludge and aerobic granular sludge using three-dimensional excitation and emission matrix (EEM) fluorescence spectroscopy. Three chemical methods (EDTA, formaldehyde, formaldehyde plus NaOH) , one physical method (cation exchange resin) and a control method (high speed centrifugation) were tested. Five fluorescence peaks were identified in EEM fluorescence spectra of the EPS samples. Two peaks were attributed to the protein-like fluorophores, two peaks were attributed to the fulvic-like fluorophores and one peak to the humic-like substance. Homogenization is absolutely necessary for the extraction of EPS from aerobic granular sludge. Formaldehyde interfered with DNA content determination. Extract residues should be removed from EPS by dialysis membrane filtration to avoid EPS contamination. Compared with the other four methods, the extraction ability of high speed centrifugation was relatively ineffective; the CER method was a correspondingly effective method which was gentler and did not cause cell lysis; although the formaldehyde plus NaOH method was most effective in extracting EPS, the quantity of DNA was the highest. EPS contamination due to NaOH and EDTA was pointed out by EEM fluorescence spectroscopy analysis.