Development of an Electrochemical Bioassay Based on the Alkaline Phosphatase Activity of Chlamydomonas reinhardtii to Assess the Toxicity of Heavy Metals

摘要

A novel electrochemical bioassay for the rapid and sensitive evaluation of heavy metals toxicity wasdeveloped using the alkaline phosphatase activity of Chlamydomonas reinhardtii (C. reinhardtii). Theinhibition of alkaline phosphatase activity caused by heavy metals was measured by quantifying theoxidation of p-aminophenol (PAP), which was produced from the enzymatic reaction of a p- aminophenyl phosphate (PAPP) substrate. The quantification of PAP oxidation was performed viacyclic voltammetry in a micro-droplet on a screen-printed carbon electrode (SPCE). The heavy metalsconcentrations that produced a 50% inhibition of enzymatic activity (EC50) for Cu, Pb, Cd, Zn, and Hg-1were 8.18, 0.10, 0.27, 1.99, and 0.07 mol L , respectively. The present method was compared with amicro-scaled algal growth inhibition test (-AGI) whereby the obtained values of EC50 were 36.2, 7.7,-18.5, 29.1, and 2.6 mol L for Cu, Pb, Cd, Zn, and Hg, respectively. By comparison with aconventional AGI test, the proposed method was much more sensitive and faster.