First characterization of activated sludge bacterial bioma by biomolecular (PCR) method

The water treatment carried out with biological processes artificially reproduces the natural process of the biogeochemical cycle of the detritus present in aquatic environments and partly in the soil. The growing biomass in the plant is called "activated sludge"; usually it is mainly composed by bacteria (95%) and by Protozoa and Metazoans (5%). Microorganisms composing activated sludge have always been of great interest to microbiologists. The sludge biological composition is e a good indicator of its state of health, and can show the need for process or management changes, the treatment potential, the possible presence in the sewage of substances harmful to the process, the sludge pathologies and the best approach to further treatment of the mud. This work is part of a full-scale experimentation project of the AS Diffusion system for the abatement of osmogenic compounds emitted by biological treatment processes (TOASD project). The task of the project concerns the verification of any effects of selective pressure on the composition of the biological sludge induced by the AS diffusion system, applied to a biological line, in comparison with a parallel line on which the system is not applied. An initial characterization of the microorganisms present in the activated sludge of the plant chosen for the project is carried out before starting the project. The characterization is carried out through the extraction of DNA, with its quantification and determination of quality. A PCR analysis follows with the identification of the main Kingdoms and phylum of bacteria, for a first screening in order to continue the investigations to identify the species present. A performance check was carried out on the preparatory and DNA extraction procedures from the biological sludge matrix and an initial characterization of the microorganisms present before the project was started, with the quantification and determination of the quality of the extracted DNA. The NucleoSpin® Soil kit from MACHEREY-NAGEL demonstrated improved qualitative and quantitative efficacy. A DNA extraction procedure from samples stored by freezing in 150 ml aliquots and gradually thawed was found to be qualitatively and quantitatively better. All sequencing confirmed the amplification of the sequence sought and produced by the PCR. DNA of generic bacteria and archaea are always present in the 16S region. The Phylum Bacteroidetes, Termotogae (Fervidobacteria sp), Chlorobi, Spirochetes are absent in the present case. Furthermore, the Deltaprotebacteria class is absent. On the confirmation of bacterial presence, the subsequent research work by species and subsequently quantification with realtime PCR will be developed.