Applied Microbiology and Biotechnology

, Volume 95, Issue 4, pp 957–968

Codon-optimized glucoamylase sGAI of Aspergillus awamori improves starch utilization in an industrial yeast

Authors

  • Lorenzo Favaro
    • Department of Agronomy Food Natural Resources Animals and Environment (DAFNAE)University of Padova, Agripolis
  • Tania Jooste
    • Department of MicrobiologyStellenbosch University
    • Department of Agronomy Food Natural Resources Animals and Environment (DAFNAE)University of Padova, Agripolis
  • Shaunita H. Rose
    • Department of MicrobiologyStellenbosch University
  • Maryna Saayman
    • Department of MicrobiologyStellenbosch University
  • Johann F. Görgens
    • Department of Process EngineeringUniversity of Stellenbosch
  • Sergio Casella
    • Department of Agronomy Food Natural Resources Animals and Environment (DAFNAE)University of Padova, Agripolis
  • Willem H. van Zyl
    • Department of MicrobiologyStellenbosch University
Applied genetics and molecular biotechnology

DOI: 10.1007/s00253-012-4001-8

Cite this article as:
Favaro, L., Jooste, T., Basaglia, M. et al. Appl Microbiol Biotechnol (2012) 95: 957. doi:10.1007/s00253-012-4001-8

Abstract

The development of a yeast that converts raw starch to ethanol in one step (called consolidated bioprocessing) could yield large cost reductions in the bioethanol industry. The aim of this study was to develop an efficient amylolytic Saccharomyces cerevisiae strain suitable for industrial bioethanol production. A native and codon-optimized variant of the Aspergillus awamori glucoamylase gene were expressed in the S. cerevisiae Y294 laboratory strain. Codon optimization resulted to be effective and the synthetic sequence sGAI was then δ-integrated into a S. cerevisiae strain with promising industrial fermentative traits. The mitotically stable recombinant strains showed high enzymatic capabilities both on soluble and raw starch (2425 and 1140 nkat/g dry cell weight, respectively). On raw corn starch, the engineered yeasts exhibited improved fermentative performance with an ethanol yield of 0.42 (g/g), corresponding to 75 % of the theoretical maximum yield.

Keywords

Industrial yeastCodon optimizationδ-integrationRaw starchEthanol production

Copyright information

© Springer-Verlag 2012