The role of Penicillium brevicompactum in bioprocessing plastic and metals from printed circuit boards

Printed circuit boards (PCB) present a complex recycling challenge due to their miniaturisation and different constituents (e.g., metals, plastics), highlighting the need for integrated bioprocessing approaches. Fungi have demonstrated the capacity to degrade plastics and leach metals from various sources, although their ability to process both fractions simultaneously remains largely unexplored. This study assessed the potential of the fungus Penicillium brevicompactum in bioprocessing PCB particles (1-2 mm, containing microplastics and a metal particle) for 7 and 28 days, in an aqueous culture medium. After 28 days of incubation with P. brevicompactum, the PCB particles showed a decrease in both weight (58 % loss) and number (up to 48 % fewer detected particles). In the presence of the fungus the copper concentration in the medium increased by up to 1.5-fold (17 ± 2 to 26 ± 3 mg/L). Fourier Transform Infrared (FTIR) spectroscopy revealed potential chemical alterations in PCB microplastics fraction, particularly a decrease in the 871-873 cm peak intensity (C-H bending in aliphatic hydrocarbons) from day 7-28, potentially indicative of changes in the epoxy-based polymer. These findings highlight the promising role of P. brevicompactum in the degradation of the polymeric constituents and solubilisation of the metal fraction, a step towards a sustainable bioprocessing of PCB waste for resource recovery and pollution mitigation.