Zinc and copper supplements enhance trichloroethylene removal by Pseudomonas plecoglossicida in water

ABSTRACT

The effects of two microelements, zinc and copper, on the aerobic co-metabolic removal of trichloroethylene (10 mg/L) by the isolate Pseudomonas plecoglossicida were investigated. The strain was previously isolated from a petroleum-contaminated site using toluene (150 mg/L) as substrate. Different concentrations (1, 10 and 100 mg/L) of microelements provided with SO₄²⁻ and Cl⁻ were tested. The results showed the supplement of Zn²⁺ and Cu²⁺ at the low concentration (1 mg/L) significantly enhanced cell growth. The removal efficiencies for toluene and trichloroethylene were also enhanced at the low concentration (1 mg/L) of Zn²⁺ and Cu²⁺. Compared to the control without zinc supplement, higher concentrations of zinc (10 and 100 mg/L) enhanced the removal efficiencies for both toluene and trichloroethylene in the first three days but showed some inhibitory effect afterward. However, the higher concentrations of Cu²⁺ (10 and 100 mg/L) always showed inhibitory to the toluene removal while showing inhibitory to the TCE removal after three days. For both Zn²⁺ and Cu²⁺, the anions SO₄²⁻ and Cl⁻ did not show significant difference in their effects on the toluene removal. A possible mechanism for Zn²⁺ and Cu²⁺ to enhance the removal of toluene and trichloroethylene would be their involvement in toluene oxygenase-based transformation processes. In addition, high concentrations of Zn²⁺ and Cu²⁺ ions could be removed from the liquid by the cells accordingly. The results imply a potential of supplementing low concentrations of zinc and copper to enhance bioremediation of the sites co-contaminated with toluene and trichloroethylene.

GRAPHICAL ABSTRACT

KEYWORDS:

• Zinc
• copper
• toluene
• trichloroethylene
• Pseudomonas plecoglossicida

Acknowledgements

This study was supported by the University of Macau Multi-Year Research Grant (MYRG2018-00108-FST) and grant from the Science and Technology Development Fund of Macao (FDCT0034/2021/AFJ).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All the data generated or analysed during this study are included in this published article.

Additional information

Funding

This study was supported by the Universidade de Macau (MYRG2018-00108-FST) and Fundo para o Desenvolvimento das Ciências e da Tecnologia (FDCT0034/2021/AFJ).