Team:Hong Kong JSS

E. coli as the synthetic absorbent
of heavy metal in aquaponics systems

Our project is inspired by the household water pollution incident that occurred in Hong Kong in 2015. Aquaponics is a popular way of farming in Hong Kong due to the limit of space. However, the aquaponic system is highly vulnerable to heavy metal pollution due to the bioaccumulation effect. Therefore, this system was chosen as a model for investigation. We previously demonstrated that E. coli itself could remove about 30% of copper pollutants in water after 4 hours. In this project, we aimed to enhance E. coli copper adsorption ability by

1) Ectopically expressing CgMT, a Metallotionien from Corynebacterium glutamicum
2) Knocking out its endogenous copper exporter genes such as cusA, copA, cutA and cusF.

In addition, a filtering device (Bacterial Copper Absorption Device, B-CAD) was built to utilize the bacteria in the real-life aquaponic systems. Results indicated that the copper level can be reduced significantly (~40% in 2 days) by our “B-CAD”.