title: Recalcitrant carbohydrates after enzymatic hydrolysis of pretreated lignocellulosic biomass.
abstract: BACKGROUND
  To reduce the cost of the enzymes for the hydrolysis of lignocellulosic biomass, two main strategies have been followed: one, the reduction of enzyme dosing by the use of more efficient and stable enzymatic cocktails; another, to include accessory enzymes in the cocktails to increase yields by reducing the recalcitrant carbohydrate fraction remaining at the end of the process. To guide this second strategy, we have explored the chemical bond composition of different fractions of recalcitrant carbohydrates after enzymatic hydrolysis.
  
  
  RESULTS
  Two lignocellulosic feedstocks of relevance for the biofuels industry have been analyzed, corn stover and sugarcane straw. On comparing the composition of chemical bonds of the starting pretreated material with samples after standard and forced hydrolysis (with enzyme overdosing), we obtained similar sugar and chemical bond composition.
  
  
  CONCLUSIONS
  This suggests that the current enzymatic cocktails bear the set of enzymes needed to hydrolyze these feedstocks. From our point of view, the results show the need for a parallel fine-tuning of the enzymatic cocktails with the pretreatment process to maximize sugar release yield.
authors.affiliation: Department of Biotechnology, Abengoa Research, Campus Palmas Altas, C/Energía Solar no 1, 41014 Seville, Spain.
authors.forename: María Ángeles Bermúdez
authors.initials: MÁ
authors.lastname: Alcántara
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, 30602 Georgia.
authors.forename: Justyna
authors.initials: J
authors.lastname: Dobruchowska
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, 30602 Georgia.
authors.forename: Parastoo
authors.initials: P
authors.lastname: Azadi
authors.affiliation: Department of Biotechnology, Abengoa Research, Campus Palmas Altas, C/Energía Solar no 1, 41014 Seville, Spain.
authors.forename: Bruno Díez
authors.initials: BD
authors.lastname: García
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla y CSIC, Américo Vespucio 49, 41092 Seville, Spain.
authors.forename: Fernando P
authors.initials: FP
authors.lastname: Molina-Heredia
authors.affiliation: Department of Biotechnology, Abengoa Research, Campus Palmas Altas, C/Energía Solar no 1, 41014 Seville, Spain.
authors.forename: Francisco Manuel
authors.initials: FM
authors.lastname: Reyes-Sosa
keywords: Bioethanol; Enzymatic hydrolysis; Lignocellulosic biomass; Recalcitrant carbohydrates