title: Maize feedstocks with improved digestibility reduce the costs and environmental impacts of biomass pretreatment and saccharification.
abstract: BACKGROUND
  Despite the recognition that feedstock composition influences biomass conversion efficiency, limited information exists as to how bioenergy crops with reduced recalcitrance can improve the economics and sustainability of cellulosic fuel conversion platforms. We have compared the bioenergy potential-estimated as total glucose productivity per hectare (TGP)-of maize cultivars contrasting for cell wall digestibility across processing conditions of increasing thermochemical severity. In addition, exploratory environmental impact and economic modeling were used to assess whether the development of bioenergy feedstocks with improved cell wall digestibility can enhance the environmental performance and reduce the costs of biomass pretreatment and enzymatic conversion.
  
  
  RESULTS
  Systematic genetic gains in cell wall degradability can lead to significant advances in the productivity (TGP) of cellulosic fuel biorefineries under low severity processing; only if gains in digestibility are not accompanied by substantial yield penalties. For a hypothetical maize genotype combining the best characteristics available in the evaluated cultivar panel, TGP under mild processing conditions (~3.7 t ha(-1)) matched the highest realizable yields possible at the highest processing severity. Under this scenario, both, the environmental impacts and processing costs for the pretreatment and enzymatic saccharification of maize stover were reduced by 15 %, given lower chemical and heat consumption.
  
  
  CONCLUSIONS
  Genetic improvements in cell wall composition leading to superior cell wall digestibility can be advantageous for cellulosic fuel production, especially if "less severe" processing regimes are favored for further development. Exploratory results indicate potential cost and environmental impact reductions for the pretreatment and enzymatic saccharification of maize feedstocks exhibiting higher cell wall degradability. Conceptually, these results demonstrate that the advance of bioenergy cultivars with improved biomass degradability can enhance the performance of currently available biomass-to-ethanol conversion systems.
authors.affiliation: Wageningen UR Plant Breeding, Wageningen University and Research Centre, P.O. Box 386, 6700 AJ Wageningen, The Netherlands ; Plant Biotechnology Laboratory (COCIBA), Universidad San Francisco de Quito USFQ, Diego de Robles y Vía Interoceánica, Cumbayá, Ecuador.
authors.forename: Andres F
authors.initials: AF
authors.lastname: Torres
authors.affiliation: Biobased Chemistry and Technology, Wageningen University and Research Centre, P.O. Box 17, 6700 AA Wageningen, The Netherlands.
authors.forename: Petronella M
authors.initials: PM
authors.lastname: Slegers
authors.affiliation: Limagrain Nederland B.V., Rilland, The Netherlands.
authors.forename: Cornelie M M
authors.initials: CM
authors.lastname: Noordam-Boot
authors.affiliation: Wageningen UR Plant Breeding, Wageningen University and Research Centre, P.O. Box 386, 6700 AJ Wageningen, The Netherlands.
authors.forename: Oene
authors.initials: O
authors.lastname: Dolstra
authors.affiliation: Limagrain Nederland B.V., Rilland, The Netherlands.
authors.forename: Louis
authors.initials: L
authors.lastname: Vlaswinkel
authors.affiliation: Biobased Chemistry and Technology, Wageningen University and Research Centre, P.O. Box 17, 6700 AA Wageningen, The Netherlands.
authors.forename: Anton J B
authors.initials: AJ
authors.lastname: van Boxtel
authors.affiliation: Wageningen UR Plant Breeding, Wageningen University and Research Centre, P.O. Box 386, 6700 AJ Wageningen, The Netherlands.
authors.forename: Richard G F
authors.initials: RG
authors.lastname: Visser
authors.affiliation: Wageningen UR Plant Breeding, Wageningen University and Research Centre, P.O. Box 386, 6700 AJ Wageningen, The Netherlands.
authors.forename: Luisa M
authors.initials: LM
authors.lastname: Trindade
keywords: Biomass yield; Cell wall digestibility; Maize; Pretreatment; Refinery; Technoeconomic