title: Laccase detoxification of steam-exploded wheat straw for second generation bioethanol.
abstract: In this work we compared the efficiency of a laccase treatment performed on steam-exploded wheat straw pretreated under soft conditions (water impregnation) or harsh conditions (impregnation with diluted acid). The effect of several enzymatic treatment parameters (pH, time of incubation, laccase origin and loading) was analysed. The results obtained indicated that severity conditions applied during steam explosion have an influence on the efficiency of detoxification. A reduction of the toxic effect of phenolic compounds by laccase polymerization of free phenols was demonstrated. Laccase treatment of steam-exploded wheat straw reduced sugar recovery after enzymatic hydrolysis, and it should be better performed after hydrolysis with cellulases. The fermentability of hydrolysates was greatly improved by the laccase treatment in all the samples. Our results demonstrate the action of phenolic compounds as fermentation inhibitors, and the advantages of a laccase treatment to increase the ethanol production from steam-exploded wheat straw.
authors.affiliation: Centro de Investigaciones Biológicas, Line of Environmental Biology, CSIC, Ramiro de Maeztu 9, E-28040 Madrid, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Jurado
authors.forename: Alicia
authors.initials: A
authors.lastname: Prieto
authors.forename: Angeles
authors.initials: A
authors.lastname: Martínez-Alcalá
authors.forename: Angel T
authors.initials: AT
authors.lastname: Martínez
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Martínez
mesh_terms: D001674:Bioelectric Energy Sources; D002850:Chromatography, Gel; D003247:Conservation of Natural Resources; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D006868:Hydrolysis; D042845:Laccase / Q000378:metabolism*; D009005:Monosaccharides / Q000378:metabolism; D010636:Phenols / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000254:growth & development; D013227:Steam; D013997:Time Factors; D014908:Triticum / Q000378:metabolism*
chemical_list: D009005:Monosaccharides; D010636:Phenols; D013227:Steam; D000431:Ethanol; D042845:Laccase