Investigation of degradation of toxic substances in fungal cultures by mass spectrometric techniques

Abstract: Micropollutants in water are biological or chemical contaminants that are present in ground and surface waters in trace quantities. They are a result of human activity and include pharmaceutically active compounds (PhACs) and endocrine disrupting compounds (EDCs). They are eluted to urban wastewater treatment plants (UWWTPs) from households, industries and hospitals. Some of the compounds are recalcitrant (persistent) which means that they enter the aquatic environments in intact forms. In this thesis, some selected micropollutants in water of environmental concern have been chosen to be investigated whether they are suited for biodegradation using filamentous fungi in non-sterile environments. The compounds of key interest were the non-steroidal anti-inflammatory drug (NSAID) diclofenac, nonylphenol polyethoxylates (NPEOs) and finally the aminoglycoside antibiotic neomycin.The white rot fungus (WRF) Trametes versicolor was chosen as the main fungal species candidate in the project. It was used in batchwise and in small scale bioreactor experiments. Mycelia of the species were immobilized on polyurethane foam (PUF) and it was shown that PUF could be used as adsorbent for diclofenac and NPEOs. Furthermore, the species could biodegrade both compounds under co-metabolic conditions (presence of external nutrients). Using UHPLC-Q-TOF MS, with reversed phase chromatography, it was possible to measure the concentration levels of these two target compounds and to tentatively identify previously known and unknown biodegradation products.A screening of 42 fungal species was performed to investigate their ability to survive and grow in a matrix containing toxic nitrogen containing industrial chemicals. Based on this investigation, it was concluded that there are species that are compatible with these harsh conditions which also contained high salt levels. From this study, the mycorrhizal fungal species Rhizoscyphus ericae was selected to be further investigated whether it can biodegrade neomycin.It was concluded that PUF immobilized Trametes versicolor is able to remove a majority of neomycin in co-metabolically performed experiments. In vitro experiments (excluding mycelia), were also performed including a laccase redox mediator system. It was feasible to tentatively determine biodegradation mechanisms that was plausible for both these experimental designs. By varying the levels of nutrients and neomycin and introducing Rhizoscyphus ericae, it was shown that this fungal species is able to use neomycin as nutrient in contrary to Trametes versicolor which only biodegrades neomycin under co-metabolic conditions.