Monday, May 5, 2008
7-34

Improvement of yield and productivity of ethanol production in yeast through artificial transcriptional factors

Yong-Su Jin1, Ki-Sung Lee1, Min-Eui Hong1, and Jin-Soo Kim2. (1) School of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon, South Korea, (2) Department of Chemistry, Seoul National University, ToolGen, Inc., Seoul, South Korea

Ethanol production not from sugar or starch-based substrates but from the hydrolyzate of lignocellulosic biomass faces outstanding problems for commercialization. Among these problems, the capability of fermenting pentose and resistance to various inhibitors from pretreatment processes of recalcitrant lignocelluose are critically required traits for optimal strains. Previous studies suggested that simultaneous perturbation of multiple genes might be needed to implement such traits. Moreover, a set of gene targets responsible for the traits is not determined yet. As such, we employed a combinatorial approach based on artificial transcriptional factor (ATF) libraries which were previously developed for genome-wide perturbation of multiple genes (1, 2). Specifically, ATF libraries consisting of DNA binding domains and an activating domain were introduced into the engineered Saccharomyces cerevisiae and improved strains were isolated under various selection conditions. As a result, recombinant yeast strains exhibiting desired phenotypes, such as high ethanol yield/productivity, and resistance to various inhibitors, were isolated. These results suggest that global perturbation of multiple genes in a simultaneous manner is needed along with a traditional pathway-based metabolic engineering approach to develop optimal strains for ethanol production from lignocellulosic biomass.

References:

  1. Park et al., Phenotypic alteration of eukaryotic cells using randomized libraries of artificial transcription factors. Nat Biotechnol. 21:1208-1214.
  2. Bae et al., Human zinc fingers as building blocks in the construction of artificial transcription factors. Nat Biotechnol. 21:275-280

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