Evaluating the simulated toxicities of metal mixtures and hydrocarbons using the alkane degrading bioreporter Acinetobacter baylyi ADPWH_recA

Li, H. and Yang, Y. and Zhang, D. and Li, Y. and Zhang, H. and Luo, J. and Jones, K.C. (2021) Evaluating the simulated toxicities of metal mixtures and hydrocarbons using the alkane degrading bioreporter Acinetobacter baylyi ADPWH_recA. Journal of Hazardous Materials, 419: 126471. ISSN 0304-3894

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Abstract

Oil spillages lead to the formation of hydrocarbon and metal mixtures possessing effects on alkane-degrading bacteria that are responsible for the bioremediation of oil-contaminated soils and waters. Studies of bacterial responses to the mixture of petroleum and metal can inform appropriate strategies for bioremediation. We employed a luminescent bioreporter Acinetobacter baylyi ADPWH_recA with alkane degradation capability to evaluate the combined effects from heavy metals (Cd, Pb and Cu) and alkanes (dodecane, tetradecane, hexadecane and octadecane). Bioluminescent ratios of ADPWH_recA in single Cd or Pb treatments ranged from 0.25 to 1.98, indicating both genotoxicity and cytotoxicity of these two metals, while ratios <1.0 postexposure to Cu showed its cytotoxic impacts on ADPWH_recA bioreporter. Metal mixtures exhibited enhanced antagonistic effects (Ti > 4.0) determined by the Toxic Unit model. With 100 mg/L alkane, the morbidity of ADPWH-recA reduced to <20%, showing the inhibition of alkanes on Cd toxicity. Exposed to the metal mixture containing 10 mg/L Cu, the weak binding affinity of Cu with alkanes contributed to a high morbidity of > 85% in ADPWH_recA cells. This study provides a new way to understand the toxicity of mixture contaminants, which can help to optimize treatment efficiencies of bacterial remediation for oil contamination.