Enhanced laccase-mediated transformation of diclofenac and flufenamic acid in the presence of bisphenol A and testing of an enzymatic membrane reactor

Abstract

The inadequate removal of pharmaceuticals and other micropollutants in municipal wastewater treatment plants, as evidenced by their detection of these substances in the aquatic environment has led to the need for sustainable remediation strategies. Laccases possess a number of advantages including a broad substrate spectrum. To identify promoting or inhibitory effects of reaction partners in the remediation processes we tested not only single compounds-as has been described in most studies-but also mixtures of pollutants. The reaction of diclofenac (DCF) and flufenamic acid (FA), mediated by Trametes versicolor laccase resulted in the formation of products, which were more hydrophilic than the respective reactant (reactant concentration of 0.1 mM; laccase activity 0.5 U/ml). Analyses (HPLC, LC/MS) showed that the product 1a and 1b for DCF and FA, respectively, to be a para-benzoquinone imine derivative. The formation of 1a was enhanced by the addition of bisphenol A (BPA). After 6 days 97% more product was formed in the mixture of DCF and BPA compared with DCF tested alone. Product 1a was also detected in experiments with micropollutant-supplemented secondary effluent. Within 24 h 67% and 100% of DCF and BPA were transformed, respectively (25 U/ml). Experiments with a membrane reactor (volume 10 l; phosphate buffer, pH 7) were in good agreement with the results of the laboratory scale experiments (50 ml). EC-values were also determined. The data support the use of laccases for the removal or detoxification of recalcitrant pollutants. Thus, the enzyme laccase may be a component of an additional environmentally friendly process for the treatment stage of wastewater remediation.

Immobilization of Enzymes in/on Membranes and their Applications

“…established a free‐enzyme membrane reactor system to produce N ‐acetylneuraminic acid . Up to the early 21 st century, EMRs had been successfully used in the food, pharmaceutical and sewage treatment industries.…”

Impact on Wastewater Quality of Biopellets Composed of <i>Chlorella vulgaris</i> and <i>Aspergillus niger</i> and Lipid Content in the Harvested Biomass

“…Certain fungal species are also of high interest for bioremediation due to their production of extracellular enzymes, such as laccases, capable of degrading recalcitrant xenobiotics [27]. Laccase-mediated degradation of diclofenac, using laccase from the white-rot fungi Trametes versicolor, has been demonstrated [28]. Decreased toxicity was also observed after treatment in that study, which is important as biodegradation processes are required not only to remove the target compound, but also its potentially toxic metabolites.…”

Toward Characterizing the Genetic Basis of Trace Organic Contaminant Biotransformation in Activated Sludge: The Role of Multicopper Oxidases as a Case Study

“…A number of studies have investigated the activities of purified MCOs against TrOCs ,,, and proposed their application for post-treatment enzymatic removal of persistent contaminants. ,, However, their role during biological wastewater treatment remains unexplored. In this study, we therefore aimed to obtain a more comprehensive understanding of their potential contribution to TrOCs elimination during activated sludge treatment, which could also point toward opportunities to devise novel biocatalysts and guide the design of treatment systems that induce their expression (e.g., physico-chemical conditions, presence of appropriate mediator compounds, etc.…”