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DESULFURIZATION OF OXIDIZED BITUMEN USING MICROORGANISMS THROUGH PROCESS-BASED DIRECTED EVOLUTION

  • Author / Creator
    De Man, Allison B
  • Many Rhodococcus species are capable of utilizing the 4S biodesulfurization pathway to convert dibenzothiophene (DBT) to 2-hydroxybiphenyl (2-HBP) and sulfite, the latter of which is partially incorporated into cell biomass. The first steps of the 4S pathway involve the oxidation of DBT into DBTO2 for further conversion. It is hypothesized that using DBTO2 as the direct substrate for desulfurization would result in faster growth rates and increased desulfurization activity. Process-based directed evolution strategies were performed, using DBTO2 as a selective pressure, with three Rhodococcus species to adapt the cultures and select for mutants with increased desulfurization activity. Process-based directed evolution was performed through two strategies: (i) sequential transfers and (ii) self-cycling fermentation (SCF). A change in desulfurization activity for Rhodococcus rhodochrous IGTS8 was observed and indicated a change in sulfur management in the cell. Rhodococcus erythropolis EPWF developed a gain-of-function mutation that enabled it to desulfurize DBTO2.

  • Subjects / Keywords
  • Graduation date
    2014-06
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/R3WH2DP37
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
    English
  • Institution
    University of Alberta
  • Degree level
    Master's
  • Department
    • Department of Chemical and Materials Engineering
  • Specialization
    • Chemical Engineering
  • Supervisor / co-supervisor and their department(s)
    • Sauvageau, Dominic (Chemical and Materials Engineering)
    • de Klerk, Arno (Chemical and Materials Engineering)
  • Examining committee members and their departments
    • Sauvageau, Dominic (Chemical and Materials Engineering)
    • Ulrich, Ania (Civil and Environmental Engineering)
    • de Klerk, Arno (Chemical and Materials Engineering)