Biodegradation of acetaminophen and its main by-product 4-aminophenol by Trichoderma harzianum versus mixed biofilm of Trichoderma harzianum / Pseudomonas fluorescens in a fungal microbial fuel cell

Our research aimed to explore the bioremediation of acetaminophen (APAP) and 4-aminophenol (PAP), as well as energy production in a dual-chamber fungal microbial fuel cell (FMFC) device. The pure culture of fungus Trichoderma harzianum and mixed culture of bacteria and fungi (Trichoderma harzianum and Pseudomonas fluorescens) were used as bioanodes. The microorganisms were compared for the first time to examine the removal efficiency of the APAP and its main by-product (PAP). The authors have applied an electrochemical approach to follow the APAP and PAP behavior in the systems. It is interesting to mention that the mixed biofilm culture was able to completely remove the APAP and PAP at around 7 h. These experiments revealed that the biodegradation rate was enhanced in bacterial-fungal biofilms about 5 times higher than in the pure culture of fungus Trichoderma harzianum. The formation of PAP was also observed during the mixed biofilm biodegradation of APAP, which was the result of bacterial degradation. The half-life of APAP biodegradation was 7 h and 1.3 h for pure and mixed biofilm cultures, respectively. Similarly, the higher removal efficiency of PAP was also obtained for the mixed culture biofilms. The PAP biodegradation kinetic constants of 0.116 h−1 and 0.066 h−1 were observed for mixed culture and fungal biofilms, respectively. In terms of MFC performance, a power density of 1.7 mW m−2 was obtained for the FMFC system working with mixed biofilm which is at least 10 times higher than that of pure fungal biofilm (0.13 mW m−2). This work led to the conclusion that a combination of bacterial-fungal biofilm Trichoderma harzianum and Pseudomonas fluorescens could be made use of to remove APAP and PAP with simultaneous electricity production.