A key strategy for bioremediation ex situ of electronic waste in aquatic media by a Penicillium citrinum P-3b strain

This study investigates the potential of the Penicillium citrinum P-3b strain for the bioremediation of printed circuit board (PCB) waste. Biodegradation was conducted ex situ in 200 mL of seawater and tap water under same conditions, with PCB weight loss monitored over a 90-day period. Surface alterations were examined using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM), while Fourier-transform infrared spectroscopy (FTIR) was employed to characterize structural modifications. The results showed substantial PCB weight reductions in both media, 96.000% in tap water and 96.377% in seawater. SEM analysis revealed fissures and cracks in both environments, with more pronounced damage in seawater. Energy-dispersive X-ray spectroscopy (EDX) identified calcium, magnesium, and silicon in both media, whereas aluminum, copper, and sulfur were detected exclusively in tap water. AFM confirmed corrosion in both aquatic systems relative to the control, again more severe in seawater. FTIR spectra indicated the emergence of new functional groups, including O–H or N–H stretching vibrations, alongside the formation of aliphatic chains and organic fragments enriched in CH2/CH3 groups, particularly in samples immersed in seawater. Collectively, these findings demonstrate the strong potential of P. citrinum P-3b as an efficient bioremediation agent for PCB contamination in aquatic ecosystems.