title: Development of a mediated whole cell-based electrochemical biosensor for joint toxicity assessment of multi-pollutants using a mixed microbial consortium.
abstract: Since most risk assessment for toxicants is based on individual single-species test, the deduction of such results to ecosystem evaluation is afflicted with uncertainties. Herein, we successfully developed a p-benzoquinone mediated whole-cell electrochemical biosensor for multi-pollutants toxicological analysis by co-immobilizing mixed strains of microorganism, including Escherichia coli (gram-negative bacteria), Bacillus subtilis (gram-positive bacteria) and Saccharomyces cerevisiae (fungus). The individual and combined toxicities of heavy metal ions (Cu(2+), Cd(2+)), phenol (3,5-dichlorophenol) and pesticides (Ametryn, Acephate) were examined. The experimental results showed that the order of toxicity for individual toxicant was ranked as Cu(2+) > 3,5-dichlorophenol (DCP) > Ametryn > Cd(2+) > Acephate. Then the toxic unit (TU) model was applied to determine the nature of toxicological interaction of the toxicants which can be classified as concentration additive (IC50mix = 1TU), synergistic (IC50mix < 1TU) and antagonistic (IC50mix > 1TU) responses. The binary combination of Cu(2+) + Cd(2+), Cu(2+) + DCP, Cu(2+) + Acephate, DCP + Acephate, Acephate + Ametryn were analyzed and the three kind of joint toxicity effects (i.e. additive, synergistic and antagonistic) mentioned above were observed according to the dose-response relationship. The results indicate that the whole-cell electrochemical biosensor based on mixed microbial consortium is more reasonable to reflect the joint biotoxicity of multi-pollutants existing in real wastewater, and combined effects of toxicants is extremely necessary to be taken into account in ecological risk assessment. Thus, present study has provided a promising approach to the quality assessment of wastewater and a reliable way for early risk warning of acute biotoxicity.
authors.affiliation: Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Guanyue
authors.initials: G
authors.lastname: Gao
authors.affiliation: Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China.
authors.forename: Jun
authors.initials: J
authors.lastname: Qian
authors.affiliation: Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Deyu
authors.initials: D
authors.lastname: Fang
authors.affiliation: Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China. Electronic address: zhi-mail@mail.ipc.ac.cn.
authors.forename: Jinfang
authors.initials: J
authors.lastname: Zhi
mesh_terms: D015374:Biosensing Techniques; D055664:Electrochemical Techniques / Q000295:instrumentation*; D005240:Feasibility Studies; D057230:Limit of Detection; D059013:Microbial Consortia / Q000187:drug effects*; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Joint toxicity; Mediated cell-based electrochemical biosensor; Mixed microbial consortium; Toxic unit