S S

S S

Aga1p

Aga2p

HA

C-mycfluorophore

Yeast cell wall

d)

a)

c)

b)

Engineering Proteins for Facile Removal of Petroporphyrins from Crude Oil

Reza A. Ghiladi, Department of Chemistry, North Carolina State University, Raleigh NC 27695-8204

Petroporphyrins are found in all fossil fuels and pose a significant challenge to the petroleum industry as their degradation results in the fouling of the precious-metal catalyst beds utilized in oil refining, thus increasing the cost of petroleum products and/or making certain sources of oil unusable. While removal of petroporphyrins is a conceptually easy solution to this problem, the challenge is that there are no known petroporphyrin-specific binding materials or degradation catalysts to accomplish this. Our primary focus has been the development of a functional Yeast Surface Display (YSD) directed evolution system to evolve heme oxygenase (hHO-1) to specifically bind and catalytically degrade petroporphyrins to facilitate their removal from crude oil. To that end, we have successfully displayed hHO-1 on the surface of yeast, and confirmed these results using Fluorescence Activated Cell Sorting (FACS). Our approach now enables rapid library screening of hHO-1 variants that will be evolved to bind, or catalytically degrade, a variety of petroporphyrins.

YSD of hHO-1

Evolved hHO-1hHO-1 FACS