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Climate change affects cell wall structure and hydrolytic performance of a tropical forage grass as an energy crop
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  • Emanuelle Freitas,
  • Vinay Khatri,
  • Daniele Contin,
  • Tassio Oliveira,
  • Alex Contato,
  • Rosane Peralta,
  • Wanderley dos Santos,
  • Carlos Martínez,
  • Jack Saddler,
  • Maria de Lourdes Teixeira de Polizeli
Emanuelle Freitas
Universidade de São Paulo
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Vinay Khatri
The University of British Columbia Faculty of Forestry
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Daniele Contin
Universidade de São Paulo
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Tassio Oliveira
Universidade de São Paulo
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Alex Contato
Universidade de São Paulo
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Rosane Peralta
Universidade Estadual de Maringá
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Wanderley dos Santos
State University of Maringá
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Carlos Martínez
Universidade de São Paulo
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Jack Saddler
The University of British Columbia
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Maria de Lourdes Teixeira de Polizeli
Universidade de São Paulo
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Abstract

Forage grasses, such as Panicum maximum, are important alternatives of lignocellulosic biomass for bioethanol production. Thus, this study investigates whether future climate conditions could influence P. maximum cell wall structure and hydrolytic performance. A combined temperature-free air controlled and a free-air carbon dioxide enrichment (Trop-T-FACE) facility was used to investigated the isolated and combined effect of elevated atmospheric CO2 concentration (eC) (600 μmol.mol-1) and elevated temperature (eT) by 2˚C more than the ambient temperature, on cell wall composition, cellulose crystallinity, accessibility, and hydrolysis yields. The elevated temperature treatments (eT and eT+eC) exhibited the most pronounced effects. Warming reduced starch content and crystallinity index (CI) of cellulose while increased cellulose content. The fluorescent protein-tagged carbohydrate-binding modules analysis demonstrated that warming led to improvement in the total cellulose surface exposure/accessibility in eT and eT+eC by 181% and 132%, respectively. Consequently, glucan conversion yields were improved by 7.07 and 5.37%, showing that warming led to lower recalcitrance in P. maximum biomass, which positively affect its use in biorefineries. Therefore, this work provides important information from an ecological and economic point of view, and might assist in the selection of tropical forage grasses efficiently adapted to climate changes with positive effect on bioenergy production.