Neomycin removal using the white rot fungus<i>Trametes versicolor</i>

Abstract

The presence of antibiotic resistance genes in wastewater treatment plants (WWTPs), and in river and lake recipients show the need to develop new antibiotic removal strategies. The aminoglycoside antibiotic class is of special concern since the chemical structure of these compounds limits the choices of removal technologies. The experimental design included fungal mediated <i>in vivo</i> and <i>in vitro</i> experiments. The experiments were performed in Erlenmeyer flasks under non-sterile conditions. In the study, the role of the laccase redox mediator 4-hydroxy benzoic acid (HBA) in the removal of neomycin was investigated. The specific objective of the study was to conclude whether it is possible to use the white rot fungus (WRF) <i>Trametes versicolor</i> to biodegrade neomycin. It was shown that it is feasible to remove 34% neomycin <i>in vitro</i> (excluding living fungal cells) by laccase-HBA mediated extracellular biodegradation. In the <i>in vivo</i> experiments, polyurethane foam (PUF) was used as supporting material to immobilize fungal mycelia on. The presence of living fungal cells facilitated a removal of approximately 80% neomycin in the absence of HBA. Using liquid chromatography-high resolution-mass spectrometry, it was possible to tentatively identify oxidation products of neomycin hydrolysates. The results in this study open up the possibility to implement a pretreatment plant (PTP) aimed for neomycin removal.