Best Composite Part
The composite part contains copA promoter, RiboJ , a gene cluster mhbDHIM, and a terminator. The promoter is induced by copper ion and transcribe downstream genes. The RiboJ between copA and the gene cluster can decrease interference of one part type (promoter) on another(protein coding sequence). The gene cluster mhbDHIM contains four connected genes which can degrade 3-hydroxybenzoate to the Fumarate and Pyruvate step by step.
After having an experiment, we found that the device can degrade the 3-hydroxybenzoate(3-HBA) completely in short time. Also, engineered bacteria with the device grows better in the medium with 3-hydroxybenzoate than Klebsiella pneumoniae M5a1 which is capable of utilizing 3-hydroxybenzoate via gentisate, and can tolerate higher concentration of 3- hydroxybenzoate. In conclusion, this part can help the E.coli degrade the 3- hydroxybenzoate effectively.
Figure1. 3-HBA was degraded thoroughly by our engineered E.coli transformed with this composite part.
Figure2. The ordinate is the concentration of 3-HBA. The left column shows the figure of Klebsiella pneumoniae M5a1, while the right one shows the figure of our engineered bacteria. From this figure we can find that our engineered bacteria can degrade 3-HBA much faster than M5a1 in 24h.