Nanochemistry and biotechnology

The influence of nanomaterials on pyocyanin production by Pseudomonas aeruginosa
Jabłońska J.1, Dubrowska K.1, Augustyniak A. 1,2, Rakoczy R.1
1 Department of Chemical and Process Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology, Szczecin, al. Piastów 42, 71-065 Szczecin, Poland. 
E-mail: joanna_jablonska@zut.edu.pl
2 Chair of Building Materials and Construction Chemistry, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355 Berlin, Germany.

Pseudomonas aeruginosa is a Gram-negative bacterium producing various metabolites such as rhamnolipids, biopolymers, and pigments. The latter includes a group of phenazines, with pyocyanin as the most studied example. Pyocyanin is a well-known virulence factor that is strongly associated with the biofilm formation process. However, it also shows the potential for application in agriculture, anticancer therapy, fabrication of colorimetric redox indices and OLED screens, and energy production in microbial fuel cells. Therefore, the potential of application of pyocyanin is widely studied, concerning both potential inhibitors and stimulants of production of pyocyanin by P. aeruginosa. In the area of interest are various chemical substances, including nanomaterials.
The study aimed to examine the influence of nanomaterials such as zinc oxide (ZnO) and multiwalled carbon nanotubes (MWCNT) on the pyocyanin yield of P. aeruginosa ATCC®27853™. The research included examining the influence of different concentrations of nanomaterials (1000.00-0.06 µg/mL) on selected bacteria's growth rate and fluorescence values. Next, the pyocyanin yield was assessed after incubation with the chosen concentrations of ZnO and MWCNT using chloroform-hydrochloric acid extraction. The statistical analysis was based on ANOVA (Tukey test) at p<0.05. 
The results show the diversified influence of the tested nanomaterials on pyocyanin yield. MWCNT exhibited a stimulative effect on pigment production when applied in high concentrations. On the other hand, higher concentrations of nanometric ZnO lowered pyocyanin production, while smaller dosages increased the concentration of the bioproduct. The research indicates the potential to use nanomaterials as the modulators of pyocyanin production.