Abstract template

Instructions

  1. Complete and upload as a Word document.
  2. Only students registered for, or having recently completed, a MSc or PhD degree at UWC will be considered.
  3. Choice of oral or poster presentations serves only as a guide for the organisers.
  4. Selections for oral presentations will be made by the relevant Department, in consultation with the organisers.

Details of presenter

Name:

Student number:Email address:

UWC Department or Unit:

Degree (MSc/PhD):Year of 1st registration:

Supervisor of degree:Email address of supervisor:

Oral/Poster presentation:

Abstract template: (Please use Times New Roman, font 12, at single spacing).

Title: In bold type and uppercase (capitals)

Authors: Surname followed by initials; do not include titles.

(Bold and Underline the presenter’s name).

Affiliation: Department, Centre or Unit. Use superscript numbers to match affiliation with author.

Abstract: Approx. 250 words max.

(See example below).

Overexpression of native Saccharomyces cerevisiae SNARE genes increased heterologous cellulase secretion.

Den Haan, R.1, Van Zyl, J.H.2, Vogel, D. 1, and Van Zyl,W.H.2

1Department of Biotechnology, University of the Western Cape, Bellville 7530, South Africa. 2Department of Microbiology, Stellenbosch University, Stellenbosch 7602, South Africa

A major obstacle to using the yeast Saccharomyces cerevisiae in single-step hydrolysis and fermentation of cellulosic material for second generation bio-ethanol production is its inferior yields of secreted heterologous cellulases. In this study we have attempted to enhance heterologous protein secretion through a rational design strategy involving proteins integral to the secretion pathway. SNAREs (soluble N-ethylmaleimide-sensitive factor attachment receptor proteins) are essential components of the yeast protein trafficking machinery and are required at the majority of membrane and vesicle fusion events in the cell. We have demonstrated an increase in secretory titers for the Talaromyces emersonii Cel7A (a cellobiohydrolase) and the Saccharomycopsis fibuligera Cel3A (a β-glucosidase) expressed in Saccharomyces cerevisiae through single and co-overexpression of some of the ER-to-Golgi SNAREs (BOS1, BET1, SEC22 and SED5). Overexpression of SED5 yielded the biggest improvements for both of the cellulolytic reporter proteins tested, with maximum increases of 22% for the Sf-Cel3A and 68% for the Te-Cel7A. Co-overexpression of the ER-to-Golgi SNAREs yielded proportionately smaller increases for the Te-Cel7A (46%), with the Sf-Cel3A yielding no improvement. Co-overexpression of the most promising exocytic SNARE components previously identified (SSO1 for Sf-Cel3A and SNC1 for Te-Cel7A) with the most effective ER-to-Golgi SNAREs (SED5 for both Sf-Cel3A and Te-Cel7A) yielded variable results, with Sf-Cel3A improved by 130% and Te-Cel7A yielding no improvement. This study has shown that SNARE proteins fulfil an essential role within a larger cascade of secretory machinery components that could contribute significantly to future improvements to S. cerevisiae as protein production host.