Development of a mediated whole cell-based electrochemical biosensor for joint toxicity assessment of multi-pollutants using a mixed microbial consortium

• Published in: Analytica chimica acta 2016-06, Vol.924, p.21-28
• Main Authors: Gao, Guanyue, Qian, Jun, Fang, Deyu, Yu, Yuan, Zhi, Jinfang
• Format: Article
• Language: English
• Subjects: Additives; Bacillus subtilis; Bacteria; Biosensing Techniques; Biosensors; Consortia; Copper; Electrochemical Techniques - instrumentation; Escherichia coli; Feasibility Studies; Joint toxicity; Limit of Detection; Mediated cell-based electrochemical biosensor; Microbial Consortia - drug effects; Microorganisms; Mixed microbial consortium; Saccharomyces cerevisiae; Toxic unit; Toxicity; Waste water; Waste Water - chemistry; Water Pollutants, Chemical - toxicity
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2016.04.011

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 (Cu2+, Cd2+), 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 Cu2+ > 3,5-dichlorophenol (DCP) > Ametryn > Cd2+ > 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) responses. The binary combination of Cu2+ + Cd2+, Cu2+ + DCP, Cu2+ + 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. [Display omitted] •In present work, a multi-species microbial biosensor with improved sensitivity and broadened detection range was developed.•The joint toxicity effect of binary toxicants was analyzed to provide a reference for biotoxicity assessment of wastewater.•A simple and low cost biosensor was fabricated, providing a reliable way for early risk warning of acute toxicity.