Poblaciones e interacciones microbianas en biorreactores de membranas (MBR)desarrollo de herramientas biológicas para el control del bioensuciamiento en sistemas de depuración de aguas residuales

Résumé

The operation of Wastewater Treatment Plants (WWTP) depends on the activity of the microbial community for the degradation of organic matter and nutrients present in the wastewater. In activated sludge processes, these microorganisms are grouped together with the suspended matter to form flocs, which will be separated from the liquid phase, to discharge the treated water safely into the environment. One of the most widely used systems for this separation is the use of membrane filtration in membrane bioreactors (MBR). In this Doctoral Thesis, the structure and dynamics of the microbial communities in a WWTP-MBR bioreactor were studied over a period of two years. This community presented a seasonal succession pattern, determined by temperature, with a certain drift that produced significant changes between both sampled years. A small fraction of the phylotypes detected formed a large part of the bacterial community, constituting a "core" microbiome, whose stability is also clearly determined by temperature. The stability patterns of this community can be inferred and monitored to determine whether the community is functioning properly. Using microbial network-based modeling and phylogenetic analysis, we observed that the succession of the bioreactor microbiota consisted of alternating two sub-communities with different environmental affinities, which alternately dominated in the warm and cold months. Furthermore, the selective pressure exerted by the bioreactor environment selects and maintains a highly functional and specialized community that responds to seasonal environmental changes. These results were contrasted with the analysis of a microbial community adapting to the new bioreactor where it had been inoculated, observing an assemblage pattern that reflects the tendency of the community to become increasingly modular and specialized...