Team:Hong Kong CUHK/overview

The goal of our project is to develop a method using E.coli to degrade polycyclic aromatic hydrocarbons (PAHs) into other less toxic chemicals. PAHs are notorious for their damage on the environment and human health. These compounds can be found anywhere, from second-hand smoke to cooking fume. The wide spread and toxicity of PAHs indeed arouse our concern and interest to tackle the issue.

We proposed the PAHs degradation system, which contains codon-optimized laccase from Bacillus sp. HR03 and catechol 1,2-dioxygenase from Pseudomonas putida KT2440 for Escherichia coli. Laccase can first degrade PAHs into quinones, and followed by catechol 1,2-dioxygenase, quinones would further be degraded into some simple carboxylic acid. The final product is a much less harmful compound to the human body. For the regulation of this PAHs degradation system, we added quinone sensing and response repressor (QsrR) from Staphylococcus aureus, as quinones are generated at the beginning of the metabolism.

Another great highlight of our project is the Voltage Switch (VS), which can help to accelerate the PAHs degradation. We designed a novel transmembrane protein called Voltage Switch (VS), which is a fusion protein utilizing the voltage sensing domain from potassium ion channels. Triggered by change in potential across the cell membrane, VS can separate or bring targeting enzymes into proximity; thus allowing an instant control of the enzymatic reaction.