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 (h. HO-1) to specifically bind and catalytically degrade petroporphyrins to facilitate their removal from crude oil. To that end, we have successfully displayed h. HO-1 on the surface of yeast, confirmed these results using Fluorescence Activated Cell Sorting (FACS), and employed error prone PCR to evolve h. HO-1. Our approach now enables rapid library screening of h. HO-1 variants that will be evolved to bind, or catalytically degrade, a variety of petroporphyrins. Evolved h. HO-1 YSD of h. HO-1 FACS