In this study, environmental samples were collected from different places to obtain various desulfurization competent cultures with increased... Show moreIn this study, environmental samples were collected from different places to obtain various desulfurization competent cultures with increased desulfurization activity. In order to obtain the cultures the soil samples were inoculated in enriched medium and minimal medium containing DBT as the sole source of sulfur. The cultures grown in minimal medium with DBT were transferred multiple times with increasing temperatures, where as the cultures grown in enriched media were grown only one cycle at 37 degrees. After a certain growth period the cells were isolated and DNA was extracted. Efforts to amplify dsz genes from the obtained cultures with universal dszABC primers were mostly unsuccessful. DNA from bacterial strains isolated from the environmental samples were amplified with universal primers and amplicons were cloned. Samples #2, #6, #17, #21, #32 were amplified successfully but sequencing analyses showed little homology with dszABC genes. DNA from samples #32*, 32*Y and 32*W was isolated with Power Soil kit and PCR analysis showed a 3 kb amplicon. Sequencing analyses, however, showed less homology with dszABC and revealed homology instead with proteins such as those involved in Fe/S biogenesis and thiol:disulphide interchange. In addition, alternate universal primers were designed and PCR analyses were made with R .erythropolis IGTS8 and sample #32*. Alternate primer combination #3 (A1 and C1) and combination #8 (B1 and C2) amplified expected bands with IGTS8 DNA. Combination #8 amplified a 1 kb band from sample #32* DNA. Cultures #32*, #32*Y and #32*W were selected due to their ability to grow in minimal medium with DBT as high as 55 ˚C for multiple transfers. These isolated cultures from a soil sample from the Chicago area are able to catabolize dibenzothiophene (DBT) to 2-hydroxybiphenyl (2-HBP), which was detected by the Gibbs assay. M.S. in Biology, May 2011 Show less
