In the present study, a disposable biofilm modified amperometric microbial sensor was developed and employed as an analytical tool for evaluating biotoxicity of pesticides and the real wastewater. The proposal biotoxicity biosensor is fabricated by using a polymeric disposable biofilm, which was prepared by immobilizing the pretreated S. cerevisiae cells (as a highly active biocatalyst), a combination of polyvinyl alcohol (PVA) hydrogel and sodium alginate crosslinked by CaCl2 as a matrix at the electrode surface. It was found that the S. cerevisiae pretreated with alcohols is needed for increasing response sensitivity of the microbial sensor, therefore, the effects of treated reagents, concentration and treating time, etc., on the performance of biosensor were optimized. Atomic force microscopy (AFM), flow cytometry (FCM), as well as the electrochemical response was employed to investigate the morphology characteristics, cells viability and electrochemical characteristics respectively. 3, 5-Dichlorophenol (DCP) was taken as the reference toxicant. The pesticides solutions, including Acephate, Ametryn and Thiram were taken as the model toxicants. The biotoxicity of three kinds of real wastewater was also determined by this amperometric microbial sensor. The traditional parameter of 50% concentration (IC50) was measured within 30 min and results obtained were better than those of other toxicity bioassays reported. The microbial biosensor prepared is a sensitive, rapid, convenient and cheap alternative to toxicity screening of chemicals and real wastewater.investigate the morphology characteristics, cells viability and electrochemical characteristics respectively. 3, 5-Dichlorophenol (DCP) was taken as the reference toxicant. The pesticides solutions, including Acephate, Ametryn and Thiram were taken as the model toxicants. The biotoxicity of three kinds of real wastewater was also determined by this amperometric microbial sensor. The traditional parameter of 50% concentration (IC50) was measured within 30 min and results obtained were better than those of other toxicity bioassays reported. The microbial biosensor prepared is a sensitive, rapid, convenient and cheap alternative to toxicity screening of chemicals and real wastewater.

RSC Advances, 2014