Diclofenac Biodegradation by Microorganisms and with Immobilised Systems—A Review

Abstract

Diclofenac is one of the most popular non-steroidal anti-inflammatory drugs. Due to its over-the-counter availability and high consumption along with municipal and hospital wastewater, it enters the sewage treatment plant, where it is not completely degraded. This results in the appearance of diclofenac in the effluents from the treatment plant, and with them, it enters the surface waters. Due to its structure, it is characterised by its high resistance to degradation in the environment. At the same time, it shows documented acute and chronic toxicity to non-target organisms. For this reason, it is necessary to look for cheap solutions that enhance the degradation of diclofenac. The paper discusses both the pathways of microbiological degradation of this drug described so far, as well as modern systems of biocatalyst immobilisation, with a particular emphasis on laccases involved in the biotransformation of diclofenac.

Application of Immobilized Biocatalysts in the Biotransformation of Non-Steroidal Anti-Inflammatory Drugs

“…On the other hand, diclofenac has two aromatic rings linked together by an amine bridge. Although the literature indicates a relatively easy cleavage of this compound into two rings, the deactivating effect of chlorine substituents in diclofenac significantly slows down the degradation process [1,2,4].…”

“…Phenol is a good carbon source for the B1 strain [17]. However, immobilization significantly affects the growth kinetics of the strains due to the limited availability of the substrate for cells [4,15]. The lack of changes in the rate of ibuprofen degradation in systems with different phenol concentrations may be related to the fact that its degradation proceeds through hydroxylation with the participation of aliphatic monooxygenase and transformation to 1,4-hydroquinone, for which acyl-CoA synthase is responsible, the enzymes of which are not induced by phenol [34,38].…”

“…This contributes to their high consumption and, consequently, their presence in sewage and the environment. Among others, naproxen and diclofenac have been found in European waters at concentration ranges of 3-753 ng/L and 1-429 ng/L, respectively [1][2][3][4]. Concentrations observed in the environment are not the root of acute toxicity.…”

“…Sci. 2023, 13 the mating behavior of fish, damage to the gills and liver, cardiac arrhythmias, teratogenic changes, and infertility [3][4][5][6]. The drug's degradation efficiency in biological wastewater treatment plants ranges from 40 to almost 100%, depending on the type of contamination, its concentration, and activated sludge properties [7,8].…”

Microalgae-based technology for wastewater treatment: exploring organic micropollutants removal

“…By biodegradation, parent OMPs that are susceptible to biomineralization can be converted into CO2 and water; thus improving the chemical and ecological quality of treated water (Nguyen et al, 2020;Usmani et al, 2020). However, biodegradation can also be incomplete, and can result in the formation of toxic transformation products (Kosjek et al, 2009;Wojcieszyńska et al, 2023). Hence, it is important to understand the mechanisms and control the extent of biodegradation of OMPs, for designing microalgae-based OMPs removal processes.…”