2011, EN, Thesis edition: Genetic characterization and manipulation of strains of Zymomonas mobilis for ethanol and higher value products Zhao, Xun, Biotechnology & Biomolecular Sciences, Faculty of Science, UNSW

User activity

Send to:
 
Bookmark: http://trove.nla.gov.au/version/168152607
Physical Description
  • Masters Thesis
Published
  • Awarded By:University of New South Wales. Biotechnology &​ Biomolecular Sciences, 2011
Language
  • EN

Edition details

Title
  • Genetic characterization and manipulation of strains of Zymomonas mobilis for ethanol and higher value products
Author
  • Zhao, Xun, Biotechnology &​ Biomolecular Sciences, Faculty of Science, UNSW
Published
  • Awarded By:University of New South Wales. Biotechnology &​ Biomolecular Sciences, 2011
Physical Description
  • Masters Thesis
Summary
  • Zymomonas mobilis has attracted considerable interest over the past decades as a result of its unique metabolism and ability to rapidly and efficiently produce ethanol. Flocculation in Z. mobilis is important commercially as a cost effective means of microbial biomass recycling to facilitate ethanol recovery and increase volumetric productivity. In this study, a flocculant mutant Z. mobilis strain ZM401 (derived from wild type strain ZM4) was used to elucidate the molecular basis of flocculation in Z. mobilis. The results of microarray analysis revealed that approximately 30 genes were significantly differentially expressed. Functional annotation indicated that the major group of genes up-regulated belonged to a cellulose synthase group (BcsA, BcsB, BcsC), while the major genes down-regulated were a group of flagella synthesis proteins (FlgBCDEF, FlgH, FliG). A further experiment established that the enzyme cellulase could efficiently deflocculate cell aggregates of ZM401, which indicated that cellulose biosynthesis was a major mechanism of cell flocculation in Z. mobilis. Studies on the inactivation of pyruvate decarboxylase (pdc) in Z. mobilis were carried out and to evaluate the possibility of a carbon-flux shift from the Entner-Doudoroff pathway towards higher value fermentation products such as (succinate, lactate). The enzymatic assay for PDC activity from the pdc inactivated strain ZM4812 confirmed that a 50% reduction in enzyme activity had occured. Fermentation experiments confirmed the reduced expression level of PDC activity resulted in reduced rates of substrate uptake and ethanol production, together with increased pyruvate accumulation and trace amounts of lactate and succinate. The increased pyruvate and trace amounts of lactate and succinate suggested that other enzymes such as pyruvate dehydrogenase (PDH) and lactate dehydrogenase and possibly other enzymes involved in production of succinic acid could serve as metabolic bottlenecks for their end-product production. Preliminary experiments were also carried out for increased PDH activity in Z. mobilis.
Terms of Use
Language
  • EN
Related Resource
  • SHELF:T/​2011/​197 (Ask at Level 2 Information Desk, UNSW Library)
Identifier
  • oai:unsworks.unsw.edu.au:unsworks:9837

Get this edition

  • Set up My libraries

    How do I set up "My libraries"?

    In order to set up a list of libraries that you have access to, you must first login or sign up. Then set up a personal list of libraries from your profile page by clicking on your user name at the top right of any screen.

  • All (1)
  • NSW (1)
None of your libraries hold this item.
None of your libraries hold this item.

This single location in New South Wales:

Library Access Call number(s) Formats held Language
University of New South Wales. UNSW Library. Open to the public Thesis EN
Show 0 more libraries...
None of your libraries hold this item.
None of your libraries hold this item.
None of your libraries hold this item.
None of your libraries hold this item.
None of your libraries hold this item.
None of your libraries hold this item.

User activity


e.g. test cricket, Perth (WA), "Parkes, Henry"

Separate different tags with a comma. To include a comma in your tag, surround the tag with double quotes.

Be the first to add a tag for this edition

Be the first to add this to a list

Comments and reviews

What are comments? Add a comment

No user comments or reviews for this version

Add a comment