Thesis defence R. Mans: yeast

16 October 2017 15:00 - Location: Aula, TU Delft - By: Webredactie

Strategies and genetic tools for engineering free-energy conservation in yeast. Promotor: Prof.dr. J.T. Pronk (TNW).

Microorganisms can be used as ‘cell factories’ to convert sugars into valuable products, in some cases providing a more sustainable alternative to petrochemical productions. These microbial fermentations preferably occur in the absence of oxygen, as aeration of large-scale bioreactors is expensive and part of the sugars is respired to CO2, thereby lowering the product yield. To enable anaerobic product formation, the metabolic pathway from sugar to product has to provide some energy (usually in the form of ATP) which the microorganisms use to grow and maintain themselves. To enable the anaerobic production of a wider range of valuable chemicals with microorganisms, the conservation of free-energy (ATP) in the metabolic reactions can be optimized. In the PhD thesis of Robert Mans, he investigates the metabolic reactions in baker’s yeast (Saccharomyces cerevisiae) for the conversion of sucrose, an important industrial sugar substrate, into lactic acid, a building block for the production of biodegradable plastics.  To this end, Mans first developed a very efficient genetic modification method, based on the recently discovered CRISPR/Cas9 system. He then used this method to genetically engineer S. cerevisiae, removing all native genes involved in transport and cleavage of sucrose. Mans then introduced a gene for sucrose transport from a plant and a gene for sucrose cleavage from a bacterium and demonstrated an increased energetic efficiency for sucrose consumption in the genetically modified S. cerevisiae strain. Additionally, Mans applied his CRISPR/Cas9 method to investigate the role of genes in the transport of the product lactic acid. This research resulted in the development of a platform strain, carrying 25 gene deletions, which can be used for further research on metabolite transport.

More information?
For access to theses by the PhD students you can have a look in TU Delft Repository, the digital storage of publications of TU Delft. Theses will be available within a few weeks after the actual thesis defence.