title: Bioprospecting and evolving alternative xylose and arabinose pathway enzymes for use in Saccharomyces cerevisiae.
abstract: Bioprospecting is an effective way to find novel enzymes from strains with desirable phenotypes. Such bioprospecting has enabled organisms such as Saccharomyces cerevisiae to utilize nonnative pentose sugars. Yet, the efficiency of this pentose catabolism (especially for the case of arabinose) remains suboptimal. Thus, further pathway optimization or identification of novel, optimal pathways is needed. Previously, we identified a novel set of xylan catabolic pathway enzymes from a superior pentose-utilizing strain of Ustilago bevomyces. These enzymes were used to successfully engineer a xylan-utilizing S. cerevisiae through a blended approach of bioprospecting and evolutionary engineering. Here, we expanded this approach to xylose and arabinose catabolic pathway engineering and demonstrated that bioprospected xylose and arabinose catabolic pathways from U. bevomyces offer alternative choices for enabling efficient pentose catabolism in S. cerevisiae. By introducing a novel set of xylose catabolic genes from U. bevomyces, growth rates were improved up to 85 % over a set of traditional Scheffersomyces stipitis pathway genes. In addition, we suggested an alternative arabinose catabolic pathway which, after directed evolution and pathway engineering, enabled S. cerevisiae to grow on arabinose as a sole carbon source in minimal medium with growth rates upwards of 0.05 h(-1). This pathway represents the most efficient growth of yeast on pure arabinose minimal medium. These pathways provide great starting points for further strain development and demonstrate the utility of bioprospecting from U. bevomyces.
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul, 136-791, South Korea.
authors.forename: Sun-Mi
authors.initials: SM
authors.lastname: Lee
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St., C0400, Austin, TX, 78712, USA.|Polymers Technology, ExxonMobil Chemical Company, 5200 Bayway Drive, Baytown, TX, 77520, USA.
authors.forename: Taylor
authors.initials: T
authors.lastname: Jellison
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St., C0400, Austin, TX, 78712, USA. halper@che.utexas.edu.|Institute for Cellular and Molecular Biology, The University of Texas at Austin, 2500 Speedway Avenue, C0400, Austin, TX, 78712, USA. halper@che.utexas.edu.
authors.forename: Hal S
authors.initials: HS
authors.lastname: Alper
mesh_terms: D001089:Arabinose / Q000378:metabolism*; D065132:Bioprospecting; D002241:Carbohydrates / Q000032:analysis; D003470:Culture Media / Q000737:chemistry; D003600:Cytosol / Q000737:chemistry; D004798:Enzymes / Q000235:genetics / Q000378:metabolism; D060847:Metabolic Engineering; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D014588:Ustilago / Q000201:enzymology* / Q000235:genetics; D014990:Xylans / Q000378:metabolism; D014994:Xylose / Q000378:metabolism*
chemical_list: D002241:Carbohydrates; D003470:Culture Media; D004798:Enzymes; D011994:Recombinant Proteins; D014990:Xylans; D014994:Xylose; D001089:Arabinose
keywords: Arabinose; Bioprospecting; Saccharomyces cerevisiae; Ustilago bevomyces; Xylose