Biodesulfurization of Petroleum and Petroleum Distillates

This research is being conducted under the direction of Dr. Charles Kulpa, Director, Center for Environmental Science & Technology and is funded by Energy Biosystems, Inc., The Woodlands, TX.

The use of bacteria to remove sulfur from crude oil or petroleum distillates
is a novel concept that presents an alternative biotechnology to the current technology of hydrodesulfurization (HDS). HDS employs high temperature catalysis and hydrogen to remove the organically bound sulfur and leave the carbon skeleton. Bacteria such as Rhodococcus have been found to carry out a similar reaction with dibenzothiophene (DBT) as a model compound. Dibenzothiophene is metabolized with the resultant release of sulfur as sulfate and the production of hydroxybiphenyl by Rhodococcus. Research at Notre Dame has focused on (1) isolating and identifying other bacteria that can catalyze similar reactions with benzothiophene and other organosulfur compounds. (2) Determining the ability of sulfate reducing bacteria to metabolize DBT and related compounds as sulfur sources. (3) Evaluate the immobilization of Rhodococcus as a mechanism for exposing biocatalyst to petroleum distillates instead of suspended biocatalyst. (4) Utilizing electron microscopy to determine the surface properties and ultrastructural features of Rhodococcus during biodesulfurization.