Schmid Markus, Thill Antoine, Purkhold Ulrike, Walcher Marion, Bottero Jean Yves, Ginestet Philippe, Nielsen Per Halkjaer, Wuertz Stefan, Wagner Michael
Lehrstuhl für Mikrobiologie, Technische Universität München, Am Hochanger 4, D-85350 Freising, Germany.
Water Res. 2003 May;37(9):2043-52. doi: 10.1016/S0043-1354(02)00616-4.
In this study we present a new approach to determine volumes, heterogeneity factors, and compositions of the bacterial population of activated sludge flocs by 3D confocal imaging. After staining the fresh flocs with fluorescein-isothiocyanate, 75 stacks of images (containing approx. 3000 flocs) were acquired with a confocal laser scanning microscope. The self-developed macro 3D volume and surface determination for the KS 400 software package combined the images of one stack to a 3D image and calculated the real floc volume and surface. We determined heterogeneity factors like the ratio of real floc surface to the surface of a sphere with the respective volume and the fractal dimension (D(f)). According to their significant influence on floc integrity and quality, we also investigated the chemical composition of flocs and quantified their bacterial population structure by using group-specific rRNA-targeted probes for fluorescence in situ hybridization. By a settling experiment we enriched flocs with poor settling properties and determined the above-mentioned parameters. This approach revealed shifts in floc volume, heterogeneity, and bacterial and chemical composition according to the settling quality of the flocs.
在本研究中，我们提出了一种通过三维共聚焦成像来确定活性污泥絮体细菌群体的体积、异质性因子和组成的新方法。在用异硫氰酸荧光素对新鲜絮体进行染色后，使用共聚焦激光扫描显微镜采集了75组图像（包含约3000个絮体）。针对KS 400软件包自行开发的宏三维体积和表面测定方法，将一组图像组合成一幅三维图像，并计算出真实絮体的体积和表面积。我们确定了异质性因子，如真实絮体表面与具有相应体积的球体表面的比率以及分形维数（D(f)）。根据它们对絮体完整性和质量的显著影响，我们还研究了絮体的化学成分，并通过使用针对荧光原位杂交的组特异性rRNA靶向探针来量化其细菌群体结构。通过沉降实验，我们富集了沉降性能较差的絮体，并确定了上述参数。该方法揭示了絮体的体积、异质性以及细菌和化学成分随絮体沉降质量的变化。
