Cottrell College Science Awards - 2014
Enabling rational design of biodesulfurization: biochemical and structural characterization of dibenzothiophene monooxygenase
Sulfur dioxide is an atmospheric pollutant generated by burning coal and petroleum products. These sulfur compounds are currently removed from crude oil by hydrodesulfurization, a complicated and costly technique that requires 300-400º C temperatures, high pressures and a metallic catalyst.
Jessica L. Vey, assistant professor of chemistry and biochemistry, California State University, Northridge, is investigating a potentially cheaper and more environmentally friendly way to remove the sulfur from carbon-based fuels.
She and her students are attempting to improve the ability of an enzyme – a biological catalyst – found in the bacterium Rhodococcus erythropolis, to promote the digestion of some naturally occurring carbon-and-sulfur compounds, rendering them harmless while retaining their value as fuel. While Vey noted carbon-based fuel industries are intrigued by the idea of using bacteria to reduce sulfur compounds, the organisms are not yet efficient enough to work commercially.
Vey is working with the first enzyme in R. erythropolis’ process of sulfur removal, a protein called dibenzothiophene monooxygenase (DszC). It is known to enhance the ability of an organic compound called “flavin” to add oxygen atoms to the sulfur compound dibenzothiophene (DBT). In this more “oxidized” state, the sulfur can be removed by other enzymes in the bacterial sulfur removal pathway.
Potentially, such a process may one day help to greatly reduce the sulfur content of fossil fuels.