Heterotrophic enzymatic biotransformations of organic micropollutants in activated sludge

While heterotrophic microorganisms constitute the major fraction of activated sludge biomass, role heterotrophs in biotransformation organic micropollutants (OMPs) has not been fully elucidated. Yet, such knowledge is essential, particularly when conceiving novel wastewater treatment plants based on a two-stage process including an A-stage under conditions and B-stage anammox activity. Biotransformation OMPs thought to mostly occur cometabolically thanks action low specificity enzymes involved metabolism primary substrates. For better understanding process, it important determine enzymatic activities underlying mechanisms biotransformation. This task proven be difficult due lack information about processes complexity biological systems present sludge. In this paper, continuous aerobic reactor following 20 at environmental concentrations was operated (i) assess potential during cometabolic OMPs, (ii) identify reactions catalyzed by (iii) predict possible responsible for biotransformations. Contradicting previous reports dominant nitrifiers removal treatment, population proved its capacity biotransform extents equivalent reported values nitrifying plants. Besides, 12 transformation products potentially formed through activity several heterotrophs, monooxygenases, dioxygenases, hydrolases transferases, were identified.