Conventional catalytic hydrodesulfurization involves high costs largely because of heavy metal deactivation of the catalysts. A potential lower-cost treatment is microbiological or enzymatic desulfurization. Recent advances at the Energy & Environmental Research Center (EERC) at the University of North Dakota have improved our understanding of sulfur-specific microbial desulfurization pathways in Rhodococcus bacteria, but further work is needed to develop a technology based on biodesulfurization.