Enhanced Production of Antimicrobial Pyocyanin Using Electromagnetic Fields and Carbon Nanotubes

Joanna Honselmann genannt Humme,1 Kamila Dubrowska,1 Dawid Sołoducha,1 Tomasz Borowski,1 Adrian Augustyniak,1,2 Rafał Rakoczy1,2 1Department of Chemical and Process Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Szczecin, Poland; 2Center for Advanced Materials and Manufacturing Process Engineering (MATPRO), Szczecin, PolandCorrespondence: Adrian Augustyniak, Department of Chemical and Process Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Szczecin, Poland, Email [email protected]: Pseudomonas aeruginosa produces pyocyanin, a phenazine antimicrobial agent against drug-resistant microorganisms. Multi-walled carbon nanotubes (MWCNTs) were shown to stimulate pyocyanin production. Since they are known for their conductivity, their stimulatory properties could be affected by electromagnetic fields (EMFs). Therefore, this study aimed to verify whether EMFs, alone or in combination with MWCNT, could serve as a process simulator for pyocyanin production, and whether the production process is optimizable.Materials and Methods: The Design of Experiment method was employed to optimize pyocyanin production by the cultures exposed to different types of EMFs alone or in combination with MWCNTs. This allowed for identifying the setup with the highest improvement in pyocyanin production. In this setup, additional assays, including conductivity, magnetic induction, ROS level, and membrane potential measurements, were performed. The antibacterial properties of the purified pigment were also assessed.Results and Discussion: The rotating magnetic field (RMF) combined with MWCNT was identified as the most effective setup for pyocyanin production (production improved by 143% compared to the control), which can be further enhanced by aeration. Significant changes in conductivity, magnetic induction, membrane potential, and ROS levels were observed. The purified pigment exhibited strong antibacterial properties, particularly against Staphylococcus aureus and Acinetobacter baumannii, which are often recognized as drug-resistant microorganisms.Conclusion: This research proposes a novel approach to bioprocessing, where the production of the desired metabolite can be stimulated through a combination of stressors.Plain Language Summary: Bacteria can produce many useful substances that are used in technology and medicine. One example is pyocyanin, a blue pigment that can kill bacteria. This study looked at whether different types of electromagnetic fields (EMF), alone or combined with tiny tubes called multi-walled carbon nanotubes (MWCNT), could help produce more pyocyanin.The researchers found that using a rotating magnetic field (RMF) with MWCNT was the best way to produce pyocyanin. Adding air made it even better. They noticed changes in the bacteria’s environment, like conductivity, intensity of the magnetic field, and levels of reactive oxygen species (ROS). The bacteria’s cell membranes also reacted differently to the RMF and MWCNT.The purified pyocyanin was highly effective at killing or inhibiting the growth of bacteria, especially Staphylococcus aureus and Acinetobacter baumannii, which are often drug-resistant. This research suggests a new way to produce useful substances by combining different stress factors. Keywords: antibacterial activity, nanomaterials, phenazines, Pseudomonas aeruginosa, stimulation