Frølund B, Griebe T, Nielsen P H
Environmental Engineering Laboratory, Aalborg University, Denmark.
Appl Microbiol Biotechnol. 1995 Aug-Sep;43(4):755-61. doi: 10.1007/BF00164784.
The enzymatic activity of activated sludge was investigated with special emphasis on the localization of the enzymes in the sludge floc matrix. Activated sludge from an advanced activated-sludge treatment plant, performing biological N and P removal, was used. An enzymatic fingerprint was established using a panel of six different enzymes. The fingerprint revealed peptidase as the most dominating specific enzyme tested. By monitoring sludge bulk enzymatic activity over a 3-month period using fluorescein diacetate as an enzyme substrate, considerable variations in activity were observed even over short periods (a few days). The variation in esterase activity was to some extent correlated to the presence of humic compounds in the sludge, but not to the sludge protein content. Comparison of full sludge enzyme activity to the activity of a batch-grown sludge culture indicated that enzymes accumulated in sludge flocs. A large proportion of the exoenzymes were immobilized in the sludge by adsorption in the extracellular polymeric substances (EPS) matrix. This was demonstrated by extraction of EPS from the activated sludge using cation exchange. Contemporary to the release of EPS a very large fraction of the exoenzymes was released into the water. This showed that the exoenzymes should be considered to be an integrated part of the EPS matrix rather than as direct indicators of the microbial activity or biomass.
对活性污泥的酶活性进行了研究，特别强调了酶在污泥絮体基质中的定位。使用了来自一个进行生物脱氮除磷的先进活性污泥处理厂的活性污泥。利用一组六种不同的酶建立了酶指纹图谱。该指纹图谱显示肽酶是所测试的最主要的特定酶。通过使用荧光素二乙酸作为酶底物，在三个月的时间内监测污泥的整体酶活性，即使在短时间内（几天）也观察到了活性的显著变化。酯酶活性的变化在一定程度上与污泥中腐殖化合物的存在相关，但与污泥蛋白质含量无关。将完整污泥的酶活性与分批培养的污泥培养物的活性进行比较表明，酶在污泥絮体中积累。大部分胞外酶通过吸附在细胞外聚合物（EPS）基质中而固定在污泥中。这通过使用阳离子交换从活性污泥中提取EPS得到了证明。与EPS的释放同时，很大一部分胞外酶释放到了水中。这表明胞外酶应被视为EPS基质的一个组成部分，而不是微生物活性或生物量的直接指标。
