title: Stress-related challenges in pentose fermentation to ethanol by the yeast Saccharomyces cerevisiae.
abstract: Conversion of agricultural residues, energy crops and forest residues into bioethanol requires hydrolysis of the biomass and fermentation of the released sugars. During the hydrolysis of the hemicellulose fraction, substantial amounts of pentose sugars, in particular xylose, are released. Fermentation of these pentose sugars to ethanol by engineered Saccharomyces cerevisiae under industrial process conditions is the subject of this review. First, fermentation challenges originating from the main steps of ethanol production from lignocellulosic feedstocks are discussed, followed by genetic modifications that have been implemented in S. cerevisiae to obtain xylose and arabinose fermenting capacity per se. Finally, the fermentation of a real lignocellulosic medium is discussed in terms of inhibitory effects of furaldehydes, phenolics and weak acids and the presence of contaminating microbiota.
authors.affiliation: Applied Microbiology, Lund University, Lund, Sweden; EMBRAPA Agroenergy, PqEB, Brasilia, 70770-901 DF, Brazil.
authors.forename: João R M
authors.initials: JR
authors.lastname: Almeida
authors.forename: David
authors.initials: D
authors.lastname: Runquist
authors.forename: Violeta
authors.initials: V
authors.lastname: Sànchez i Nogué
authors.forename: Gunnar
authors.initials: G
authors.lastname: Lidén
authors.forename: Marie F
authors.initials: MF
authors.lastname: Gorwa-Grauslund
mesh_terms: D001089:Arabinose / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005818:Genetic Engineering; D006868:Hydrolysis; D007218:Industrial Microbiology; D010429:Pentoses / Q000378:metabolism*; D011134:Polysaccharides / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D013312:Stress, Physiological; D014994:Xylose / Q000378:metabolism
chemical_list: D010429:Pentoses; D011134:Polysaccharides; D000431:Ethanol; C007916:hemicellulose; D014994:Xylose; D001089:Arabinose