Application of fungal-based microbial fuel cells for biodegradation of pharmaceuticals: Comparative study of individual vs. mixed contaminant solutions.

Abstract

The present study focuses on the application of fungal-based microbial fuel cells (FMFC) for the degradation of organic pollutants including Acetaminophen (APAP), Para-aminophenol (PAP), Sulfanilamide (SFA), and finally Methylene Blue (MB). The objective is to investigate the patterns of degradation (both individually and as a mixture solution) of the four compounds in response to fungal metabolic processes, with an emphasis on evaluating the possibility of generating energy. Linear Sweep Voltammetry (LSV) has been used for electrochemical analysis of the targeted compounds on a Glassy Carbon Electrode (GCE). A dual chamber MFC has been applied wherein the cathodic compartment, the reduction reaction of oxygen was catalyzed by an elaborated biofilm of Trametes trogii, and the anodic chamber consists of a mixed solution of 200 mg L^-1 APAP, PAP, MB, and SFA in 0.1 M PBS and an elaborated biofilm of Trichoderma harzianum. The obtained results showed that all the tested molecules were degraded over time by the Trichoderma harzianum. The biodegradation kinetics of all the tested molecules were found to be in the pseudo-first-order. The results of half-lives and the degradation rate reveal that APAP in its individual form degrades relatively slower (0.0213 h^-1) and has a half-life of 33 h compared to its degradation in a mixed solution with a half-life of 20 h. SFA showed the longest half-life in the mixed condition (98 h) which is the opposite of its degradation as individual molecules (20 h) as the fastest molecule compared to other pollutants. The maximum power density of the developed MFC dropped from 0.65 mW m^-2 to 0.32 mW m^-2 after 45.5 h, showing that the decrease of the residual concentration of molecules in the anodic compartment leads to the decrease of the MFC performance.