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Surface water can contain a complex mixture of organic micropollutants (i.e. residues of pharmaceuticals or biocides). Conventional wastewater treatment plants (WWTPs) do not completely remove a broad range of anthropogenic chemicals and therefore represent a leading point source. To upgrade WWTPs, technical solutions based on oxidative and sorptive processes have been developed and successfully implemented. Acknowledging these substantial advances, this thesis focuses on another key topic and aims to investigate whether improved biological treatment processes likewise effectively remove anthropogenic micropollutants from wastewater. The work conducted on this topic was part of two European research projects (ATHENE, ENDETECH). The ATHENE project aimed to go beyond the state-of-the-art by developing biological wastewater treatment processes that exploit the full potential of biodegradation. With the objective to explore the potential of complementary strictly anaerobic conditions within the biological wastewater treatment, combinations of aerobic and anaerobic treatments on site of a WWTP were implemented. Based on pre-experiments, two promising treatment combinations were selected for a more comprehensive evaluation. An aerobic treatment was paired with an anaerobic pre-treatment under iron-reducing conditions, and an activated sludge treatment was combined with an anaerobic post-treatment under substrate-limiting conditions. For the evaluation of these processes, an effect-based assessment was applied and combined with chemical data of 31 selected target organic micropollutants as well as ten metabolites. To assess the removal of endocrine disrupting chemicals (EDCs), yeast based reporter gene assays covering seven receptor-mediated mechanisms of action including (anti-)estrogenicity, (anti-) androgenicity, retinoid-like, and dioxin-like activity were conducted. Furthermore, the removal of unspecific toxicity (Microtox assay) and oxidative stress response as a marker for reactive toxicity (AREc32 assay) were analyzed to cover micropollutants acting via a non-specific mechanism of action. Moreover, to assess toxicity of the whole effluent in vivo, standardized in vivo bioassays with four aquatic model species (Desmodesmus subspicatus, Daphnia magna, Lumbriculus variegatus, Potamopyrgus antipodarum) were performed. The combination of aerobic and anaerobic treatments resulted in a low additional removal of the selected target organic micropollutants (by 14-17%). In contrast, the removal of endocrine and dioxin-like activities (by 17-75%) and non-specific in vitro toxicities (by 27-60%) was significantly enhanced. Compared to technical solutions (i.e. ozonation), the combination with an anaerobic pre-treatment under iron-reducing conditions was likewise effective in removing the estrogenic activity as well as the unspecific toxicity, whereas anti-androgenic activity and dioxin-like activity were less effectively removed. Exposure to effluents of the conventional activated sludge treatment did not induce adverse in vivo effects in the investigated aquatic model species. Accordingly, no further improvement in water quality could be observed. In conclusion, the combination of aerobic and anaerobic treatment processes significantly enhanced the removal of specific and non-specific in vitro toxicities. Thus, an optimization of the biological wastewater treatment can lead to a substantially improved detoxification. These capacities of a treatment technology can only be uncovered by complementary effect-based measurements. The global objective of the ENDETECH project was to develop a biotechnological solution to eliminate recalcitrant pharmaceuticals in wastewater direct from sites, where high loads are expected (i.e. hospitals). For this purpose, laccase, an enzyme mainly found in wood decaying fungi, was immobilized on ceramic membranes for application in bioreactors. In a proof of principle experiment, the performance of immobilized laccase in removing a mixture of 38 antibiotics without and in combination with a natural mediator (syringaldehyde; SYR) was investigated. For the evaluation of the enzymatic membrane bioreactors, chemical data on the elimination of the selected target antibiotics was combined with the outcomes of two in vitro bioassays. Growth inhibition tests with an antibiotic sensitive Bacillus subtilis strain were conducted to assess the residual antibiotic activity of the effluents, and Microtox assays were performed to detect a potential formation of toxic by-products. The treatment by laccase without SYR did not reduce the load of antibiotics significantly. In contrast, in combination with a SYR concentration of 10 µmol L-1, 26 out of 38 antibiotics were removed by >50% after 24 h treatment. Moreover, increasing the SYR concentration to 1000 µmol L-1 resulted in a further improvement of the antibiotic removal. 32 out of 38 antibiotics were removed by over 50%, whereby 17 were almost completely eliminated (>90%). However, the treatment with laccase in combination with SYR resulted in a time-dependent increase of unspecific toxicity. While SYR alone did not affect B. subtilis, the combination of laccase with SYR led to a strong time-dependent growth inhibition up to 100%. Similar to that, a time-dependent increase of unspecific toxicity in the Microtox assay was observed. In conclusion, the laccase-mediator process successfully degrades a broad spectrum of antibiotics and thus represents a promising technology to treat wastewater from sites, where high loads are expected. However, further research is required to reduce the formation of unspecific toxicity before an implementation of this technology can be considered.

Im Rahmen einer Schwerhörigkeit kommt es nicht nur zu Umbauvorgängen in der Cochlea, sondern auch die neuronalen Strukturen der Hörbahn sind betroffen. Dabei finden sich ein Verlust von Neuronen und eine Degeneration der auditorischen Kerngebiete. In den vergangen Jahren sind neuronale Stammzellen im Ganglion spirale, im Nucleus Cochlearis und im Colliculus inferior beschrieben worden. Diese Zellen könnten genützt werden, um der Degeneration der Hörbahn entgegenzuwirken. Es sind aber noch grundlegende Fragen offen, insbesondere nach einer möglichen Interaktion dieser Zellen, welche eine Voraussetzung für einen therapeutischen Einsatz wäre. Um dieses zu untersuchen wurde ein Zellkultursetup entwickelt, welches es ermöglichte, die Zellen als Stammzellen getrennt zu propagieren und dann als differenzierte Einzelzellen gemeinsam zu kultivieren. Nach definierter Zeit in Kultur wurden die Zellen fixiert und mit spezifischen Antikörpern gegen neuronale, nicht neuronale und synaptische Proteine gefärbt. Es fand sich in Kultur eine Interaktion aller drei neuronalen Stammzelltypen mit einem zeitlich abhängigen Aspekt. Die Zellen differenzierten in dem sich gebildeten Netzwerk in alle drei Zellarten der neuronalen Zelllinie aus. Zwischen neuronal differenzierten Zellen konnte eine Synapsenbildung beobachtet werden. Erste funktionelle Untersuchungen ergaben eine neuronale Aktivität. Zusammenfassend konnten mit dem neuen Setup neuronale Stammzellen unterschiedlicher Kerngebiete der Hörbahn gemeinsam kultiviert werden. In zukünftigen Projekten sollen diese Zellen auch auf molekularbiologischer und funktioneller Ebene im Sinne eines in-vitro Modelles der Hörbahn untersucht werden. Der Erstautor gibt keinen Interessenkonflikt an., GMS Current Posters in Otorhinolaryngology - Head and Neck Surgery; 13:Doc004