Biopolymers and cell. 2007; 23 (6): 511 - 518

Conductometric biosensor based on whole-cell microalgae for assessment of heavy metals in wastewater

A. L. Berezhetskyy, C. Durrieu, H. Nguyen-Ngoc, J.-M. Chovelon, S. V. Dzyadevych, C. Tran-Minh

Whole-cell Chlorella vulgaris conductometric biosensors consisting of gold planar interdigitated electrodes and sol-gel algal membranes have been used for assessment of heavy-metal ions in waste water. These ions act as algal alkaline phosphatase (AP) inhibitors. The enzyme residual activity has been measured in Tris-nitrate buffer in the presence of Mg²⁺ ions as activator. The operating conditions for this biosensor have been optimized and its characteristics are discussed. The detection limits are about 1 ppb for Cd²⁺, Co²⁺, Ni²⁺, Pb²⁺ and 10 ppb for Zn²⁺. The storage stability of the biosensor in buffer solution at 4°C is more than 40 days. The biosensor has been used to assess waste water pollution.

Keywords: Chlorella vulgaris, thin-film planar interdigitated electrodes, sol-gel immobilization, inhibitor analysis