Our project aims to degrade 3-PBA thoroughly which is a metabolite of pyrethroid, because it does harm to ecology.For it does harm to ecology.
We formed two kinds of engineering bacterias to degrade 3-HBA and 3-PBA. Each engineering bacteria has the whole system to degrade respective target material.
Engineering bacteria to degrade 3-PBA
We added our engineering bacteria into liquid medium with different concentration of 3-PBA to test bacteria`s ability of degradation. After testing we found that 20-60% of 3-PBA in medium was degraded within 60 hours.(Fig.1A) We can obviously find the decrease of 3-PBA in medium whose original concentration is 200μmol/L.(Fig.1B) Also, after testing the absorbance of the bacterial fluid, we found that our engineering bacteria growed faster than CK which does not contain the gene of degradation.(Fig.1C)
Fig.1 A Concentration of 3-PBA in liquid medium kept decreasing when added our engineering bacteria.
B The concentration of the medium decreases obviously when the concentration of the medium is 200μmol/L
C Engineering bacteria growed better than common E.coli which has no gene of degrading 3-PBA.
Engineering bacteria to degrade 3-HBA
To test the ability of degrading 3-HBA of the engineering bacteria, we added the bacteria into the liquid which contains different concentration of 3-HBA. We found that our engineering bacteria can degrade 3-HBA fast. 3-HBA will be degraded thoroughly within 12 hours when its concentration is below 5000μmol/L.(Fig.2)
Fig.2 3-HBA can be degraded thoroughly within 24 hours even its concentration has reached up to 7500μmol/L.
To make our engineering bacteria work under real-world conditions, we designed a physical unit(Fig.3) to help bacteria settle down. Also ,we can use the unit to test our engineering bacteria`s ability of degrading in laboratory.
Fig.3 The three-dimensional graph of our unit.
The water which needs to be treated enters the unit from the right tube of the unit, and leaves the unit from the left tube of the unit. Our engineering bacteria is designed to be placed in room 4 to degrade 3-PBA(Fig.4), so that 3-PBA in water can be degraded to make water become environmentally friendly.
Fig.4 The side elevation of our unit.