Effects of plasma-activated water on copper, chromium, and nickel bioremediation by Alborzia kermanshahica

<h2>Abstract</h2> Cyanoremediation represents an effective method for removing heavy metals from the environment. In this study, we investigated the potential of plasma-activated water (PAW) treatment to enhance the removal of Cu²⁺, Cr³⁺, and Ni²⁺ by <i>Alborzia kermanshahica</i>. PAW was generated using an atmospheric plasma jet device (ACPJ-17A) and applied to the culture medium of the bacterium for 0, 5, 10, 15, and 20 min to identify the optimal exposure time. The efficiency of Cu²⁺, Cr³⁺, and Ni²⁺ removal was assessed after 48 h of cultivation, with measurements taken at 0, 10, 30, 60, and 90 min under controlled conditions. Results showed that longer PAW exposure improved metal removal, with the highest rates observed after 90 min of exposure to 20-min-treated PAW. <i>Alborzia kermanshahica</i> showed the highest affinity for Cu²⁺ (Cu²⁺ > Cr³⁺ > Ni²⁺). FTIR analysis indicated that 10 min of PAW treatment was optimal for metal binding via functional groups. Longer treatments (15–20 min) reduced functional groups but still improved metal removal. GC-MS analysis showed increased levels of 3-methyl butyl ester acid in all metal treatments under 15- and 20-min exposures. Methylbenzene compounds also increased in Cu²⁺ and Cr³⁺ treatments compared to the controls. These findings illustrate that <i>Alborzia kermanshahica</i>, in combination with optimized PAW treatment, holds strong potential as a sustainable tool for heavy metal bioremediation.