盐度冲击下MBR污泥SMP和EPS的三维荧光光谱解析

利用三维荧光(EEM)技术研究了不同盐度冲击下膜-生物反应器(MBR)污泥微生物溶解性产物(SMP)和胞外聚合物(EPS)的变化规律,分析不同盐度冲击下MBR污泥SMP和EPS的EEM图谱.结果表明,当冲击盐度大于2.5g/L时,SMP的EEM图谱中色氨酸荧光峰B(270nm,350nm)、类胡敏酸荧光峰C(375,475nm)、类富里酸荧光峰D(260,460nm)以及EPS的EEM图谱中色氨酸荧光峰B的荧光强度随冲击盐度的提升而增加,EPS的EEM图谱中类胡敏酸C峰的荧光强度则随冲击盐度的提升而下降.用平行因子分析(PARAFAC)方法确定EEM图谱中存在的4个组分,分别为类蛋白质组分C1(230/280,350nm),类胡敏酸组分C2(290/310,380nm)、C3(290/360,460nm)和C4(270/340,440nm);当冲击盐度大于2.5g/L时,SMP中C1、C3和C4组分的荧光强度与冲击盐度呈正相关,而EPS中C3和C4组分的荧光强度分别与冲击盐度呈正相关和负相关,其相关系数均≥0.90;SMP中类蛋白质荧光组分和类胡敏酸组分的荧光强度之和分别与测定的蛋白质含量和胡敏酸含量呈明显的正相关性,相关系数均＞0.93,可作为荧光组分强度定量计算的依据,而EPS中此相关性并不明显.

Analysis of the EEM Fluorescence Spectra of the SMP and EPS in MBR sludge under salinity shock

Variations of soluble microbial products (SMP) and extracellular polymeric substances (EPS) extracted from MBR sludge under different salinity shock were studied using excitation-emission matrix fluorescence spectroscopy. Analysis of the EEM spectra showed that the fluorescence intensity of tryptophan protein-like peak B (270nm, 350nm), humic-acid-like Peak C (375, 475nm), fulvic-acid-like Peak D (260, 460nm) in the EEM spectra of SMP and Peak B in the EEM spectra of EPS increased as salinity shock increased. Peak C in the EEM spectra of EPS decreased as salinity shock increased when salinity shock was over 2.5g/L. Four components were identified from the EEMs by PARAFAC, which were protein-like C1 (230/280, 350nm), humic-acid-like C2 (290/310, 380nm), C3 (290/360, 460nm) and C4 (270/340, 440nm), respectively. When the salinity shock was over 2.5g/L, the fluorescence intensity of C1, C2 and C3 in SMP were positively correlated with the salinity shock. The fluorescence intensity of C3 and C4 in EPS were positively and negatively correlated (with correlation coefficients30.90) with the salinity shock, respectively. The total fluorescence intensity of the protein-like component and humic acid-like component had positive correlations with humic acid and protein content determined by chemical methods (with correlation coefficients＞0.93) which can be used for the quantitative calculation. However, there were no obvious correlations in EPS.