Team:UMaryland/Improve
Improve
Increasing the Efficacy of PETase
One of the factors that affects the efficiency of plastic biodegradation is the concentration of degrading enzyme near the surface of plastic. If the enzyme is allowed to diffuse in solution freely, it is less likely to interact with plastic. Degradation may accelerate if the enzyme is highly concentrated around the surface of plastic with some method. The bacterium Ideonella sakaiensis was reported to have grown in a biofilm which enveloped plastic pieces. As such, we first considered maximizing production of biofilm on plastic. While researching this possibility we found that the ITB Indonesia 2017 had attempted a similar project. They developed a system that facilitated biofilm production and expressed PETase simultaneously. Their results indicated that biofilm formation actually inhibited degradation, possibly due to its matrix physically blocking the transfer of enzymes to plastic.
We therefore decided to investigate an alternative method for localizing concentration while simultaneously allowing for greater interaction of substrate with enzyme. Imperial College of London in 2014 developed parts for a cellulose binding domain (CBD). This domain was capable of being incorporated with other subunits such as GFP. They were able to demonstrate that a GFP + CBD fusion protein was capable of binding to bacterial cellulose. Equipped with this information, we decided to develop a fusion protein which incorporated PETase and CBD. We assembled this part, and its characterization is available on the registry. We have tested the functionality of both its PETase component and its cellulose binding component. The part also includes an HlyA secretion sytem, but we were unable to confirm secretion.
Our hypothesis is that we can wrap bacterial cellulose around plastic to act as a scaffold on which the PETase can easily work in close proximity to the substrate. This should, in turn, increase the degradation rate. A model of our predictions can be found on the modeling page.
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umarylandigem@gmail.com
Biology - Psychology Building
4094 Campus Dr, College Park, MD 20742
umarylandigem@gmail.com
Biology - Psychology Building
4094 Campus Dr, College Park, MD 20742
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