• Login
    View Item 
    •   Home
    • Graduate Theses, Dissertations and Projects
    • Queen's Graduate Theses and Dissertations
    • View Item
    •   Home
    • Graduate Theses, Dissertations and Projects
    • Queen's Graduate Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Enhancement of the microbial biotransformation of (-)-trans-carveol to (R)-(-)-carvone by Rhodococcus erythropolis DCL14 in various two phase partitioning bioreactor configurations

    Thumbnail
    View/Open
    Morrish_Jenna_LE_200801_MSc.pdf (1.667Mb)
    Date
    2008-02-06
    Author
    Morrish, Jenna Lee Ellen
    Metadata
    Show full item record
    Abstract
    Carvone is a flavor and fragrance compound that is prominent in nature and is found in the essential oils of many plants. Carvone exists as two enantiomers, (R)-(-)-carvone which has a spearmint aroma and (S)-(+)-carvone which has a caraway aroma and can be used in a variety of applications: as a common food additive, as an antimicrobial/antifungal agent and as a potato sprout inhibitor. Carvone is currently produced by the extraction of essential oils from plants where the yield and quality of the extracted oil depends largely on successful agricultural production of dill, spearmint and caraway plants. Biotechnological production can offer a constant supply of carvone that is independent of several agricultural limitations.

    In this study, it was confirmed that the substrate and product of the microbial biotransformation of trans-carveol to (R)-(-)-carvone by Rhodococcus erythropolis DCL14 can be inhibitory to the cells at high concentrations. As such, a two phase partitioning bioreactor was employed where the function of the second phase (immiscible organic solvent or solid polymer beads) was to partition the inhibitory substrate into the aqueous phase at a rate governed by the metabolic demand of the cells and uptake the inhibitory product as it accumulated in the aqueous phase. Rational selection strategies were employed when determining the appropriate organic solvent and solid polymer to be used as the second phase. The performance of the reactor was evaluated based on volumetric productivity, length of biotransformation and total volume of substrate added to the reactor. The most successful reactor configuration was one in which styrene/butadiene copolymer beads were used as a second phase in the reactor and the fermentation medium was continuously circulated through an external extraction column packed with Hytrel® 8206 polymer beads. The volumetric productivity, length of biotransformation and total volume of substrate added to this reactor were 99 mg/L.h, 48.75 h and 35 mL, respectively whereas in the single phase benchmark reactor the performance indicators were only 31 mg/L.h, 15.25 h and 5 mL, respectively. These results clearly show the advantage of employing a partitioning bioreactor configuration for the biotechnological production of high value chemical species that exhibit cytotoxicity.
    URI for this record
    http://hdl.handle.net/1974/1025
    Collections
    • Queen's Graduate Theses and Dissertations
    • Department of Chemical Engineering Graduate Theses
    Request an alternative format
    If you require this document in an alternate, accessible format, please contact the Queen's Adaptive Technology Centre

    DSpace software copyright © 2002-2015  DuraSpace
    Contact Us
    Theme by 
    Atmire NV
     

     

    Browse

    All of QSpaceCommunities & CollectionsPublished DatesAuthorsTitlesSubjectsTypesThis CollectionPublished DatesAuthorsTitlesSubjectsTypes

    My Account

    LoginRegister

    Statistics

    View Usage StatisticsView Google Analytics Statistics

    DSpace software copyright © 2002-2015  DuraSpace
    Contact Us
    Theme by 
    Atmire NV