Abstract

Hometown Hangzhou is widely known by water- related UNESCO World Heritages – West Lake and Grand Canal, however, severe water pollution problem caused by many reasons also exist. Hence, we hope to provide an easy-operating and low-cost tool for public to monitor water quality around.

We designed a portable water quality bio-detector prototype based on E.coli strains which were constructed to detect dissolved oxygen, phosphorus or nitrogen in water respectively. The oxygen sensitive vgb promoter and a GFP reporter constitute Oxygen detector 1.0. To enhance the expression of GFP, version 2.0 contains a vgb promoter, a T7 RNA polymerase gene, a T7 promoter and a GFP gene. For nitrogen, the PyeaR promoter was used to response to different concentrations of nitrate, nitrite and nitric, with a BFP reporter gene. For phosphate, a plasmid consisting of an ‘external phosphate sensing promoter’ to sense the phosphate concentration and a RFP gene to report.