Removal of Endocrine Disrupting Chemicals in Wastewater by Enzymatic Treatment with Fungal Laccases

Abstract

In this study the enzymatic degradation of hormones and endocrine disrupting compounds (EDCs) was investigated in artificial mixtures and in real wastewater by fungal laccases (Trametes versicolor, Myceliophthora thermophila). Several studies have already reported the successful enzymatic degradation of EDCs. However, with regards to a large-scale application, the influence of some factors such as enzyme immobilization and costs are often lacking. Furthermore, the majority of studies investigated the removal of EDCs by chemical analysis only, while our main interest was to use bioassays to study the decrease in the endocrine activity. The removal of estrogenic, androgenic, and antiandrogenic activity was assessed by yeast-based reporter gene assays and the degradation of industrial chemicals by an additional chemical analysis. It was demonstrated that the degradation of hormones and EDCs by laccases is feasible even at very low enzyme concentrations (2.8 ABTS U/L). In the artificial mixtures the main removal mechanism was adsorption onto immobilization supports. In binary mixtures, immobilized laccase was best in removing EDCs within the first 6 h of exposure (83% for T. versicolor and 87% for M. thermophila), but in the course of the experiment adsorption superimposed this removal after 24 h (99% after 24 h). A similar pattern was seen in wastewater, but with less carrier material (lower adsorption) and a constant enzyme activity, immobilized laccase showed the best removal rates of estrogenic (82% removal after 24 h) and androgenic activity (99% removal after 6 h). With this in mind, this enzymatic technology can be a valuable addition to other treatment technologies.

Laccase removal of 2‐chlorophenol and sulfamethoxazole in municipal wastewater

“…An alternative approach is to mitigate the amount of laccase required by immobilizing it on a carrier or by recovering it and recycling it within the treatment system. Immobilizing laccase onto a carrier can yield high removals (Chen, Stemple, Kumar, & Wei, ; Le et al., ) although immobilization can sometimes lower activity relative to free laccase (Becker et al., ). Recently, several systems are under development to recycle laccase within wastewater treatment systems (Arca‐Ramos, Eibes, Feijoo, Lema, & Moreira, ; Lloret et al., ).…”

“…No additional mediators were added to the reaction mix although, since a whole fungal culture was used, many natural mediators were likely present. Finally, Becker et al (2017) examined the removal of endocrine disrupting compounds from municipal wastewater using laccases immobilized on carriers. Removal of EDCs was efficient even at low enzyme concentrations although adsorption onto the immobilized carrier system was a significant removal mechanism; in contrast, direct addition of free laccase into batch reactors did not yield significant EDC removal.…”

The Use of Algae and Fungi for Removal of Pharmaceuticals by Bioremediation and Biosorption Processes: A Review

“…It was found that Phanerochaete chrysosporium, a major WRF, does not have laccase genes [104]. Trametes versicolor is a WRF frequently cited in the literature that was shown to be effective in the removal of different pharmaceuticals (Table 1) [46,47,[50][51][52][53][54][55][57][58][59][60][61][62]72].…”

“…Becker et al [57] showed that the degradation of hormones by laccases is feasible even at very low enzyme concentrations, and that immobilized enzymes displayed better removal performance compared to the free enzyme. Indeed, enzyme immobilization provides a more suitable environment for enzymes and may result in an increasing enzyme stability concerning pH, temperature, and storage time.…”

Approaching Immobilization of Enzymes onto Open Porous Basotect®

“…A possible application for immobilized enzymes is the elimination of hazardous trace substances from wastewater or drinking water [46,47]. The oxidoreductase laccase was immobilized on PEMA-functionalized BT and tested in an application in order to demonstrate an alternative possibility to reduce water pollution of anthropogenic contaminants.…”