Before purification,

small and large particles covered with cells as well as cell aggregates were observed in the UASS samples (Figure 2A, D). After application of purification procedure 1-C2-S2-H1-F2, these large particles were no longer present in the samples (Figure 2B, E). The microscopic analysis of residues on the filter (Figure 2C, F) resulted in only few single cells and cell free particles. This confirmed the results of purification treatment shown in Figure 2 (B, C). Figure 2 Microscopic verification of purification procedure 1-C2-S2-H1-F2 at 400× magnification. A-C) Microscopic image of UASS-1 Copanlisib reactor. D-F) Microscopic image of UASS-2 reactor at different times of sampling. Images A and D represents samples before purification procedure, images B and E represent samples after purification procedure whereas images C and F show residues on the filter. All samples were diluted 500-fold. Cells were stained with DAPI. Microscopic buy INCB024360 images were generated using a Nikon Optiphot-2 microscope (Nikon, Duesseldorf, Germany) and a DAPI AMCA filter tube. Scale bar equals 50 μm. In conclusion,

the procedure 1-C2-S2-H1-F2 using 0.5% sodium hexametaphosphate as detergent in combination of 60 W ultrasound treatment for 60 sec and a final filtration showed the best results and was subsequently used for the pretreatment of UASS biogas reactor samples for microbial analysis by Flow-FISH. However, it must be noted that, depending on the actual grade of heterogeneity of the biogas reactor sample, the optimized purification procedure will require some time. Figure 3 illustrates the different steps of the optimized purification procedure established in this study and the principle of the Flow-FISH technique. Figure 3 Schematic figure illustrating the design clonidine and the principles of Flow-FISH protocol established in this study. (A) Single steps

of optimized purification procedure 1-C2-S2-H1-F2. (B) The purified sample is used for Flow-FISH, a combination of fluorescence in situ hybridization (FISH) and a subsequent analysis by flow cytometry. During FISH the 16S rRNA molecules of target microorganisms are hybridized with fluorescence labeled oligonucleotides (FISH probes). Samples with fluorescence labeled microorganisms are analyzed by flow cytometer. In the flow cell fluorescently labeled particles are delivered in single file to pass a focused light beam. The fluorescence emission of labeled cells is detected simultaneously with the detection of the scattered light of particles in two directions representing the cell size and granularity. *SHMP = sodium hexametaphosphate. Establishment of a Flow-FISH protocol Flow cytometry is a rapid high-throughput technique for the examination of microbial cells and a process in which characteristics of single cells are measured in a fluid stream [32].