title: Codon-optimized glucoamylase sGAI of Aspergillus awamori improves starch utilization in an industrial yeast.
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.
authors.affiliation: Department of Agronomy Food Natural Resources Animals and Environment, University of Padova, Agripolis, Viale dell'Università 16, Legnaro, Padua, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Favaro
authors.forename: Tania
authors.initials: T
authors.lastname: Jooste
authors.forename: Marina
authors.initials: M
authors.lastname: Basaglia
authors.forename: Shaunita H
authors.initials: SH
authors.lastname: Rose
authors.forename: Maryna
authors.initials: M
authors.lastname: Saayman
authors.forename: Johann F
authors.initials: JF
authors.lastname: Görgens
authors.forename: Sergio
authors.initials: S
authors.lastname: Casella
authors.forename: Willem H
authors.initials: WH
authors.lastname: van Zyl
mesh_terms: D001230:Aspergillus / Q000201:enzymology* / Q000235:genetics; D001483:Base Sequence; D003062:Codon; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D005285:Fermentation; D005087:Glucan 1,4-alpha-Glucosidase / Q000378:metabolism*; D008938:Mitosis; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D013213:Starch / Q000378:metabolism*
chemical_list: D003062:Codon; D017931:DNA Primers; D013213:Starch; D005087:Glucan 1,4-alpha-Glucosidase