AN EFFORT TO DISCOVER NOVEL BACTERIAL DSZ GENES TO HELP IMPROVE THE BIODESULFURIZATION OF CRUDE OIL Salazar, Joelle Krieger In this thesis study, soil samples were procured from various locations thought to contain high petroleum content, such as gas stations. Those samples were enriched for those that contained bacteria that were able to metabolize sulfur-containing compounds, such as DBT. The bacteria were then subjected to various experiments to determine if they possess any or all of the genes (dsz) encoding the three enzymes of the dibenzothiophene desulfurization pathway, as compared with R. erythropolis IGTS8. This feat was accomplished by using both growth experiments on medium containing dibenzothiophene as the sole sulfur source and genomic DNA extraction followed by PCR with dszABC universal primers. The resultant amplified DNA was then ligated to pGEM®-T Easy vector and transformed into electrocompetent E. coli cells. The transformants were subsequently screened and sent for sequencing. Using Blast, the sequences were analyzed. No obvious dsz homologies were identified although homologues in some cases to enzymes involved in sulfur metabolism were found. Several isolates were found to have dsz-like activity via the growth experiments as well as the Gibbs assay, which measures accumulation of the end product of the dsz-encoded pathway, 2-HBP Soil sample #32 showed promise in growth experiments in that the culture grew well in M9 with DBT as the sole sulfur source at temperatures of 30 °C, 37 °C, 45 °C, and 55 °C. Streaking the culture discovered two colonies with distinct morphology that were designated 32-W and 32-Y, for white and yellow colonies. 32-W and 32-Y also grew independently in M9 with DBT. Positive Gibbs Assays were obtained from the cultures 32-mixed, 32-W, and 32-Y. M.S. in Biology, May 2011 Stark, Benjamin C. 2011-04-25 2011-05 Thesis application/pdf islandora:6676 http://hdl.handle.net/10560/2525 BIOL / Biology Illinois Institute of Technology en In Copyright http://rightsstatements.org/page/InC/1.0/ Restricted Access