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Chemical pretreatment of Arundo donax L. for second-generation ethanol production
Lemões, Juliana Silva; Silva, Claudia Fernanda Lemons e; Avila, Sabrina Peres Farias; Montero, Cândida Raquel Scherrer; Silva, Sérgio Delmar dos Anjos e; Samios, Dimitrios & Peralba, Maria do Carmo Ruaro
Abstract
Background: Pretreatment of lignocellulosic biomass is essential for using it as a raw material for chemical and
biofuel production. This study evaluates the effects of variables in the chemical pretreatment of the Arundo
biomass on the glucose and xylose concentrations in the final enzymatic hydrolysate. Three pretreatments
were tested: acid pretreatment, acid pretreatment followed by alkaline pretreatment, and alkaline pretreatment.
Results: The amounts of glucose and xylose released by the enzymatic hydrolysis of the Arundo biomass obtained
from acid pretreatment ranged from 6.2 to 19.1 g/L and 1.8 to 3.1 g/L, respectively. The addition of alkaline
pretreatment led to a higher yield from the enzymatic hydrolysis, with the average glucose concentration 3.5
times that obtained after biomass hydrolysis with an acid pretreatment exclusively. The use of an alkaline
pretreatment alone resulted in glucose and xylose concentrations similar to those obtained in the two-step
pretreatment: acid pretreatment followed by alkaline pretreatment. There was no significant difference in
5-hydroxymethylfurfural, furfural, or acetic acid concentrations among the pretreatments.
Conclusion: Alkaline pretreatment was essential for obtaining high concentrations of glucose and xylose. The
application of an alkaline pretreatment alone resulted in high glucose and xylose concentrations. This result is
very significant as it allows a cost reduction by eliminating one step.
Keywords
Acid pretreatment; Alkaline pretreatment; Arundo biomass; Biofuel; Enzymatic hydrolysis; Giant reed; Glucose; Lignocellulose; Response surface methodology; Xylose; Raw material
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